Stephen O. Andersen policy success story , Marcel L ...whan/ATOC4800_5000/Spring_2017/Mat… ·...

This article was downloaded by: [University of Colorado at Boulder Libraries]On: 17 April 2014, At: 07:36Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House,37-41 Mortimer Street, London W1T 3JH, UK

Journal of the Air & Waste Management AssociationPublication details, including instructions for authors and subscription information:http://www.tandfonline.com/loi/uawm20

Stratospheric ozone, global warming, and the principleof unintended consequences—An ongoing science andpolicy success storyStephen O. Andersen a , Marcel L. Halberstadt b & Nathan Borgford-Parnell aa Institute for Governance and Sustainable Development , Washington , DC , USAb Michigan Retired Engineer Technical Assistance Foundation , Livonia , Michigan , USAAccepted author version posted online: 09 Apr 2013.Published online: 22 May 2013.

To cite this article: Stephen O. Andersen , Marcel L. Halberstadt & Nathan Borgford-Parnell (2013) Stratospheric ozone,global warming, and the principle of unintended consequences—An ongoing science and policy success story, Journal of the Air& Waste Management Association, 63:6, 607-647, DOI: 10.1080/10962247.2013.791349

To link to this article: http://dx.doi.org/10.1080/10962247.2013.791349

PLEASE SCROLL DOWN FOR ARTICLE

Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) containedin the publications on our platform. However, Taylor & Francis, our agents, and our licensors make norepresentations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of theContent. Any opinions and views expressed in this publication are the opinions and views of the authors, andare not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon andshould be independently verified with primary sources of information. Taylor and Francis shall not be liable forany losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoeveror howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use ofthe Content.

This article may be used for research, teaching, and private study purposes. Any substantial or systematicreproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in anyform to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/terms-and-conditions

http://www.tandfonline.com/loi/uawm20

http://www.tandfonline.com/action/showCitFormats?doi=10.1080/10962247.2013.791349

http://dx.doi.org/10.1080/10962247.2013.791349

http://www.tandfonline.com/page/terms-and-conditions

http://www.tandfonline.com/page/terms-and-conditions

2013 CRITICAL REVIEW

Stratospheric ozone, global warming, and the principle of unintendedconsequences—An ongoing science and policy success storyStephen O. Andersen,1,⁄ Marcel L. Halberstadt,2 and Nathan Borgford-Parnell11Institute for Governance and Sustainable Development, Washington, DC, USA2Michigan Retired Engineer Technical Assistance Foundation, Livonia, Michigan, USA⁄Please address correspondence to: Stephen O. Andersen, Institute for Governance and Sustainable Development, 2300 Wisconsin Ave NW,Washington, DC 20007, USA; e-mail: [email protected]

In1974,MarioMolinaandF. SherwoodRowlandwarned that chlorofluorocarbons (CFCs) could destroy the stratospheric ozone layerthat protects Earth from harmful ultraviolet radiation. In the decade after, scientists documented the buildup and long lifetime of CFCs inthe atmosphere; found theproof thatCFCs chemically decomposed in the stratosphere and catalyzed the depletionof ozone; quantified theadverse effects; and motivated the public and policymakers to take action. In 1987, 24 nations plus the European Community signed theMontreal Protocol. Today, 25 years after theMontreal Protocol was agreed, everyUnitedNations state is a party (universal ratification of196 governments); all parties are in compliance with the stringent controls; 98% of almost 100 ozone-depleting chemicals have beenphased out worldwide; and the stratospheric ozone layer is on its way to recovery by 2065. A growing coalition of nations supports usingthe Montreal Protocol to phase down hydrofluorocarbons, which are ozone safe but potent greenhouse gases. Without rigorous scienceand international consensus, emissions of CFCs and related ozone-depleting substances (ODSs) could have destroyed up to two-thirds ofthe ozone layer by 2065, increasing the risk of causing millions of cancer cases and the potential loss of half of global agriculturalproduction. Furthermore, because most ODSs are also greenhouse gases, CFCs and related ODSs could have had the effect of theequivalent of 24–76 gigatons per year of carbon dioxide. This critical review describes the history of the science of stratospheric ozonedepletion, summarizes the evolution of controlmeasures and compliance under theMontreal Protocol and national legislation, presents areview of six separate transformations over the last 100 years in refrigeration and air conditioning (A/C) technology, and illustratesgovernment–industry cooperation in continually improving the environmental performance of motor vehicle A/C.

Implications: The comforts and conveniences ofmodern life are largely taken for granted.When purchasing a product, consumersare usually not concerned with howor why it works, often assuming the product is safe to use and safe for the environment. This criticalreview addresses why such general public acceptance and complacency is not always the best policy. The paper explains how earlywarnings given by vigilant scientists highlighted the dangers of ODS and calls for action and boycotts by concerned citizens 35 yearsago and regulatory actions taken by governments worldwide 25 years ago successfully phased out ODSs and avoided globalcatastrophe. It also highlights new opportunities for the Montreal Protocol to further protect against climate change. The implicationis that scientific vigilance, public policy, and citizen action have protected and can protect Earth for future generations.

Supplemental Materials: Supplemental materials are available for this paper. Go to the publisher’s online edition of the Journal ofthe Air & Waste Management Association.

Introduction

Without a protective ozone layer in the atmosphere, animalsand plants could not exist, at least upon land. It is therefore of thegreatest importance to understand the processes that regulate theatmosphere’s ozone content. (Royal Academy of Sciences,announcing the 1995 Nobel Prize for Chemistry for PaulCrutzen, Mario Molina, and F. Sherwood Rowland)

Ozone is naturally present in the atmosphere and has thechemical formula O3. About 10% of ozone is in the troposphereand the remaining ozone (90%) resides in the stratosphere,primarily between the top of the troposphere and about 50 km(31miles) altitude. The large amount of ozone in the stratosphere

is often referred to as the “ozone layer.” In the stratosphere,approximately 16–50 km (10–31 miles) above Earth’s surface,ozone forms a thin invisible shield protecting life below from thesun’s ultraviolet (UV) radiation. In the troposphere, near Earth’ssurface, ozone is produced by chemical reactions of naturallyoccurring gases and gases from fossil fuel combustion and otherpollution sources. Tropospheric ozone is a human health concernand also damages animals and plants. Stratospheric ozoneabsorbs the shorter wavelengths (UV-C: 100–280 nm) comple-tely and transmits only a small fraction of the middle wave-lengths (UV-B: 280–315 nm). Nearly all of the longerwavelengths (UV-A: 315–400 nm) are transmitted to Earthwhere they cause skin aging and degrading of outdoor plastics

607

Journal of the Air & Waste Management Association, 63(6):607–647, 2013. Copyright © 2013 A&WMA. ISSN: 1096-2247 printDOI: 10.1080/10962247.2013.791349

Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

and paint. Of the two types of UV radia-tion reaching ground level, UV-B is themost harmful to humans and other lifeforms.

Manufactured ozone-depleting sub-stances (ODSs) now controlled by theMontreal Protocol include approxi-mately 100 chemicals containing chlor-ine and bromine once used in about 240different applications, but are nowphased out in 98% of uses, with theexception of feedstock and processagent use, which are exempt from con-trols as long as emissions are de minimis.Table 1 lists a number of halogen sourcegases and some of their properties rele-vant to this discussion. Nitrous oxide(N2O) is the largest remaining anthropo-genic threat to the stratospheric ozonelayer not yet controlled by the MontrealProtocol, but it is controlled under the1997 Kyoto Protocol as a potent green-house gas (GHG) (Kanter et al. 2013).ODSs controlled under the MontrealProtocol include chlorofluorocarbons(CFCs) and hydrochlorofluorocarbons(HCFCs) used widely as aerosol productpropellants, refrigerants, foam blowingagents, and solvents; halons used for fireprotection; carbon tetrachloride used asa solvent and fire extinguishing agent;methyl chloroform used as a solvent;

and methyl bromide used as a pesticide and fire extinguishingagent. Once emitted, ODSs accumulate in the atmosphere and aretransported by wind and convection to the stratosphere, wherethey are chemically decomposed by UV-B, releasing chlorineand bromine atoms that destroy ozone. As ozone is depleted,increased transmission of UV-B radiation endangers humanhealth and the environment by increasing skin cancer andcataracts, weakening human immune systems, and damagingcrops and natural ecosystems (Fahey and Hegglin, 2011; Slaperet al., 1998; UNEP, 2010a). The most conspicuous healtheffects are melanoma, basal-cell carcinoma and squamous-cell carcinoma (Chang et al., 2009; de Gruiji et al., 2003;Kripke, 1974; Norval et al., 2007; Swaminathan and Lucas,2012; van Hattem et al., 2009; van der Leun and de Gruijl,2002; van der Leun et al., 2008), and cataracts (Ayala et al.,2007; Meyer et al. 2008; Oriowo et al., 2001; Norval et al.,2007; Vojnikovic et al. 2007; Rivas et al., 2009). The mostuncertain health effects are the suppression of the humanimmune system (Damian et al., 1998; Narbutt et al., 2005;Norval et al., 2007; Wang et al., 2008). The most economicallydamaging impact might have been to agricultural and naturalecosystems (Caldwell, 1971; Caldwell et al., 1986; Caldwellet al., 2007). Approximately two out of three commercial plantspecies appear sensitive to UV-B, and sensitivity also differsamong cultivars of the same species. For example, the Essex

cultivar of soybean exhibited 19 to 25% yield reduction whilethe Williams cultivar was unaffected by increased radiation(Teramura and Sullivan, 1991; Tevini, 1998). Most ODSs arealso “greenhouse gases” that contribute to global warmingleading to effects of climate change, including sea-level rise,intensification of storms, and changes in precipitation andtemperature distributions (Ramanathan, 1975; Ramanathanet al., 1985; Velders et al., 2007; Schneider et al., 2007; IPCC2012).

The narrative that follows describes the 225-year history ofstratospheric ozone science and policy response, followed by acritical review of six separate transformations over the last 100years in refrigeration and air conditioning (A/C) technology; itillustrates government–industry cooperation in continuallyimproving the environmental performance of motor vehicleA/C. Figure 1 is a 1960 to 2010 timeline of milestones inozone science, assessment, Montreal Protocol controls, and thedramatic reduction in integrated ODS emissions projected to2020 (Fahey and Hegglin, 2011).

ODSs are often powerful GHGs, but they are not within thegroup of six gases controlled by the Kyoto Protocol: carbondioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluor-ocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluor-ide (SF6). ODSs were already scheduled for phase-out under theMontreal Protocol, and their inclusion in the Kyoto agreementwould have provided an advantage to countries with large, easy-to-halt ODS emissions in uses such as CFC aerosol products thathad already been banned in many other countries (Benedick,1998; Andersen and Sarma, 2002). However, the Kyoto Protocoldoes include HFCs, which are ozone-safe substitutes for ODSs inrefrigeration, air conditioning (A/C), and thermal insulating foamand for SF6 and PFCs, which are minor substitutes for ODSs inmedical, fire protection, and some other applications. The KyotoProtocol group also includes N2O, which is an ozone-depletingGHG not yet controlled by the Montreal Protocol (Ravishankara2012 and Kanter et al., 2013).

Looking back, it is fortunate that (1) basic science was inplace as the foundation of stratospheric ozone depletion theory,(2) enough ecological deterioration and disasters had occurred tomake global environmental effects credible public concerns, (3)at least some scientists were confident and concerned enough toconfront corporate stakeholders who denied the science and usedsometimes ruthless tactics to discredit the scientists, (4) strato-spheric ozone monitoring networks had been collecting datalong enough to be credible, and (5) a sufficient number ofcountries were ready and willing to work with the UnitedNations Environment Program (UNEP) on a treaty based onthe precautionary principle to avoid irreversible effects fromozone depletion predicted by a theory, but not yet proven to thesatisfaction of the political and corporate interests who wouldaccomplish an ODS phase out (Benedick, 1998; Andersen andSarma, 2002).

It was also important that business and military organizationsheeded an environmental warning based on complex atmo-spheric science and that the phase-out of chemicals suspectedto deplete the stratospheric ozone layer began with public boy-cotts, corporate pledges, and action in a few countries long

Nathan Borgford-Parnell

Marcel L. Halberstadt

Stephen O. Andersen

Andersen et al. / Journal of the Air & Waste Management Association 63 (2013) 607–647608

Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

before the Montreal Protocol controls restricted ODS productionand consumption (U.S. EPA and Department of Defense [DoD],2008; Singh et al., 2009).

Early Science Links Ozone to UltravioletExposure

The smell of ozone was mentioned in the Iliad and theOdyssey in 850 BC (Homer, 850 BC), but the science of theozone aloft began not much more than two centuries ago, atmo-spheric ozone monitoring began just 90 years ago, stratosphericozone depletion theories were published just 40 years ago, thefirst national regulations of ODSs were instituted just 30 yearsago, and the first international ozone treaty was 25 years ago(United Nations Environment Programme [UNEP] 2012a;Andersen and Sarma, 2002). CFCs were invented 85 years agoand were phased out globally in 2010, with most other ODSs

already phased out or scheduled for phase-out in developedcountries by 2030 and by 2040 in developing countries.

In 1785 when Martinus van Marum replicated the ozonesmell by passing electric sparks through oxygen (O2), he termedit the “electrical odour” (Stolarski, 1999). In 1840, Swiss che-mist Christian Schönbein associated this odor with a chemicalcomponent of the lower atmosphere, not electricity, and named it“ozone,” from the Greek word ozein, “to smell” (Leeds, 1879). Afew years later, J. L. Soret of Switzerland identified ozone as anunstable form of O2 composed of three atoms of oxygen.

In 1879, the Parisian Marie-Alfred Cornú measured the sun’sspectrum with newly developed techniques for UV spectroscopyand found that the intensity of the sun’s UV radiation decreasedrapidly at wavelengths below about 300 nm (Cornú, 1879). Hedemonstrated that the wavelength of the “cutoff ” increased asthe sun set and the light passed through more atmosphere on itspath to Earth and surmised that the cutoff was the result of anatmospheric substance absorbing light at UV wavelengths.W. N. Hartley (1880) concluded that this substance filtering

Table 1. Atmospheric lifetimes, global emissions, ozone depletion potentials, and global warming potentials of some halogen source gases and HFC substitute gases

Halogen source gasAtmosphericlifetime (years)

Global emissions in2008 (kt/yr) a

Ozone depletionpotential (ODP) c

Global warming potential(GWP100 yr)

c

ChlorineCFC-11 45 52–91 1 4750CFC-12 100 41–99 0.82 10,900CFC-113 85 3–8 0.85 6130Carbon tetrachloride

(CCl4)26 40–80 0.82 1400

HCFCs 1–17 385–481 0.01–0.12 77–2220Methyl chloroform

(CH3CCl3)5 Less than 10 0.16 146

Methyl chloride 1 3600-4600 0.02 13Bromine

Halon-1301 65 1–3 15.9 7140Halon-1211 16 4–7 7.9 1890Methyl bromide

(CH3Br)0.8 110–150 0.66 5

Very short-lived gases(e.g., CHBr3)

Less than 0.5 b b Very low b Very low

Hydrofluorocarbons (HFCs)HFC-134a 13.4 149�27 0 1430HFC-23 222 12 0 14800HFC-143a 47.1 17 0 4470HFC-125 28.2 22 0 3500HFC-152a 1.5 50 0 124HFC-32 5.2 8.9 0 675HFO-1234yf 11 days n.a. 0 4

Notes: aIncludes both human activities (production and banks) and natural sources. Emissions are in units of kilotonnes per year (1 kilotonne¼ 1000 metric tons¼ 1gigagram¼ 109 grams). bEstimates are very uncertain for most species. c100-yr GWPs updated from IPCC AR4; data on HFO-1234yf from Nielsen et al. (2007).Values are calculated for emissions of an equal mass of each gas. Source: Updated by the authors from Fahey and Hegglin (2011).

Andersen et al. / Journal of the Air & Waste Management Association 63 (2013) 607–647 609

Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

UV radiation was ozone (Hartley, 1880). Hartley and Cornúsoon attributed the absorption of solar radiation between wave-lengths of 200 and 320 nm to ozone, and concluded that most ofthe ozone must be in the upper atmosphere. The firstInternational Polar Years (IPYs), from 1881 to 1884, involveda dozen nations (Luedecke, 2004).

Robert John Strutt (fourth Baron of Rayleigh) (1918) wasunable to measure the absorption by ozone from a light source

located ~6.4 km across a valley and concluded that “there mustbe much more ozone in the upper air than in the lower.”

In 1924, Dobson and Harrison (1926) invented a spectrophot-ometer, the first instrument for routinely monitoring total ozone,called a Féry spectrometer, which made its measurements byexamining the spectra of solar ultraviolet radiation using photo-graphic plates. Dobson, Harrison, and colleagues discovered day-to-day and seasonal variations in the ozone amount over Oxford,

Figure 1. Major milestones in the history of stratospheric ozone depletion (Fahey and Hegglin, 2011).


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

England. Dobson hypothesized that these variations in ozonemight be related to atmospheric pressure. To test this idea, heconstructed more spectrophotometers and distributed themthroughout Europe. These measurements demonstrated ozonevariations with the passage of weather systems (Dobson, 1968).

F. W. P. Götz (1931) worked with Dobson’s Féry spectrometerat Arosa, Switzerland, measuring the intensity ratio of two wave-lengths at the zenith sky throughout the day. He found that theseratios decreased as the sun set but increased just as the sun wasnear the horizon. He named this the Umkehr (turnaround) effectand devised the Umkehr method for measuring the vertical dis-tribution of ozone, thereby showing that the ozone concentrationreaches a maximum below an altitude of 25 km (NASA, 2000).

Sydney Chapman (1931) was first to identify the (strato-spheric) ozone “layer” and to develop a photochemical theoryof stratospheric ozone formation and destruction, based on thechemistry of pure O2 with sunlight generating O3 when absorbedby molecular oxygen (O) in the atmosphere. In the 1930s,scientist Dorothy Fisk (1934) described the critical role theozone layer plays as a global sunscreen that allows enough UV-B for beneficial exposure. The combined work of Chapman,Fisk, and Charles Abbott from the Smithsonian Institutioninspired the scientific appreciation that the ozone layer protectsliving organisms from shortwave UV light (Cagin and Dray,1993) The second IPY, 1932 and 1933, involved 44 nations.

The Chapman mechanism is shown as follows:O3 is produced by the photodissociation of O2 by solar UV

radiation:

O2 þ hnðl < 242 nmÞ ! Oþ O (1)

2½Oþ O2 þM ! O3 þM� (2)

Net : 3O2 þ hn ! 2O3 (3)

The following reaction sequence then recycles O3 back into O2:

O3 þ hnðl < 242 nmÞ ! Oþ O2 (4)

Oþ O3 ! 2O (5)

Net : 2O3 þ hn ! 3O2 (6)

F. Götz et al. (1934) experimentally confirmed the Chapmantheory of ozone formation and loss by determining that theshape of the turnaround was dependent on the shape of thealtitude profile of the ozone concentration.

In preparation for the International Geophysical Year (July1957 to December 1958), aworldwide network was developed tomeasure ozone profiles and the total column abundance of ozoneusing the equipment and standard quantitative procedure pio-neered by Dobson. The World Meteorological Organization(WMO) established the framework for ozone-observing projectsand related research and publications; this network eventuallybecame the Global Ozone Observing System (GOOS), with 140stations. In 1957 the British Antarctic Survey and Japanese

Scientific Stations in Antarctica installed Dobson ozone moni-tors, which eventually recorded the depletion of the ozone thatwas later called the Antarctic Ozone Hole.

Scientists Identify Threats to the OzoneLayer

In 1970 Paul Crutzen called attention to the fact that nitricoxide (NO) and nitrogen dioxide (NO2) react in a catalytic cyclethat destroys ozone, without being consumed themselves, thuslowering the steady-state amount of ozone. “Natural” nitrogenoxides are formed in the lower atmosphere through chemicalreactions involving N2O that originates from microbiologicaltransformations at the ground as a result of both natural andhuman activities (Kanter et al., 2013). Therefore, Crutzenwarned, increasing atmospheric concentration of nitrous oxidethat can occur through the use of agricultural fertilizers mightlead to reduced ozone levels (Crutzen, 1970). His hypothesis wasthat “NO and NO2 concentrations have a direct controlling effecton the ozone distributions in a large part of the stratosphere, andconsequently on the atmospheric ozone production rates.”

N2O provides nitrogen oxides (NOx) for catalyzed O3

destruction in the stratosphere. A typical set of reactions is:

N2Oþ hn ! N2 þ O ð1DÞ (7)

Oð1DÞ þ N2O ! 2NO ! N2 þ O2 (8)

NOþ O3 ! NO2þO2 (9)

Oþ NO2 ! NO þ O2 (10)

Net : Oþ O3 ! 2O2 (11)

Harrison (1970) hypothesized that the projected fleets of 850 super-sonic transport (SST) aircraft could diminish the ozone column andincrease surface temperatures in the Northern Hemisphere.

Johnson (1971) showed that NO andNO2 produced in the high-temperature SSTexhaust could contribute to ozone loss by releas-ing NOx directly into the stratospheric ozone layer. McDonald(1971) theorized that even a small change in the abundance ofstratospheric ozone could increase UV radiation at the surface ofthe Earth. Johnson estimated that “the operation of SSTs at thenow-estimated fleet levels predicted for 1980–1985 could soincrease transmission of solar UV radiation as to cause somethingon the order of 5–10,000 additional skin cancer cases per year injust the U.S. alone” (McDonald, 1971; Johnston, 1971).

Crutzen (1972) presented estimates of the ozone reduction thatcould result from the operation of SSTs. Wofsy and McElroy(1974) estimated that “nitric oxide emitted by SSTs would leadto a significant reduction in the concentration of atmosphericozone.” Concern over stratospheric ozone was a contributing fac-tor when the U.S. House of Representatives voted not to continuefunding development of the Boeing SST, and JapanAir Lines, PanAm, Qantas, and TWA canceled their orders for Concorde SSTs.


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

The Union of Soviet Socialist Republics (USSR) abandoned com-mercial flights of the Tupolev Tu-144d SST after a crash insideRussia in 1978 (an earlier model Tu-144 had crashed at the 1973ParisAir Show).OnlyBritishAirways andAir France operated theConcorde SST (Andersen and Sarma, 2002). Abandonment oflarge fleets of SSTs perhaps avoided a major ozone depletiondisaster as occurred from emissions of ODSs (Dubey, 1997).

Chlorine threats to the ozone layer and climate

Lovelock (1971) measured CFCs in air samples collectedaboard a research vessel in the North and South Atlantic andwarned that there may be consequences of these long-lived man-ufactured gases. CFCs were detected in every sample, “whereverand whenever they were sought” (Lovelock et al., 1973). Heconcluded that CFC gases had already spread globally.

Responding to Lovelock’s findings, the DuPont Companyformed a panel on the ecology of fluorocarbons for the world’sCFC producers in 1972 (Glas, 1989). The invitation letter stated:

Fluorocarbons are intentionally or accidentally ventedto the atmosphere worldwide at a rate approachingone billion pounds per year. These compounds maybe either accumulating in the atmosphere or returningto the surface, land or sea, in the pure form or asdecomposition products. Under any of these alterna-tives, it is prudent that we investigate any effectswhich the compounds may produce on plants oranimals now or in the future. (McCarthy, 1972)

Nineteen companies formed the Chemical ManufacturersAssociation Fluorocarbon Program Panel, a research group thateventually funded at least US$20 million in research at academicand government facilities worldwide.

In 1972, Stolarski and Cicerone concluded that hydrogenchloride spread as exhaust along the Space Shuttle’s launch tra-jectory would deplete ozone, but that the global impact would benegligible given the low frequency of planned launches.

Molina and Rowland (1974), in the first to study the atmo-spheric fate CFCs (then referred to as chlorofluoromethanes,CFMs), were first to warn that CFCs could deplete stratosphericozone. Molina and Rowland hypothesized that CFCs that arehighly unreactive would accumulate in the troposphere andwould migrate to the stratosphere where UV radiation wouldcause them to decompose and release chlorine atoms, which inturn become part of a chain reaction where a single chlorine atomcould destroy as many as 100,000 molecules of O3, therebydepleting stratospheric ozone. They warned that stratosphericozone depletion would increase the intensity of UV radiation atthe earth’s surface, increasing skin cancer and other health andenvironmental effects (Molina and Rowland, 1974).

A typical mechanism for ozone depletion by CFCs is:

CFCl3 þ hn ! CFCl2 þ Cl (12)

Clþ O3 ! ClOþ O2 (13)

ClOþ O ! Clþ O2 (14)

The free chlorine atom can then react with another O3 molecule:

Clþ O3 ! ClOþ O2 (15)


and again:Clþ O3 ! ClOþ O2 (17)


and again potentially for thousands of times until air containingreactive halogen gases returns to the troposphere where they areremoved by moisture in clouds and rain.

Molina and Rowland (1974) concluded:

Chlorofluoromethanes are being added to the envir-onment in steadily increasing amounts. These com-pounds are chemically inert and may remain in theatmosphere for 40–150 years, and concentrationscan be expected to reach 10 to 30 times presentlevels. Photo-dissociation of the chlorofluoro-methanes in the stratosphere produces significantamounts of chlorine atoms, and leads to the destruc-tion of atmospheric ozone. . . . It seems quite clearthat the atmosphere has only a finite capacity forabsorbing Cl atoms produced in the stratosphere,and that important consequences may result. Thiscapacity is probably not sufficient in steady stateeven for the present rate of introduction of chloro-fluoromethanes. (pp. 810, 812)

Molina and Rowland (1974) estimated that “if industry contin-ued to release a million tons of CFCs into the atmosphere eachyear, atmospheric ozone would eventually drop by 7 to 13percent.” At that time, global production of CFCs was approxi-mately 500,000 metric tonnes per year, with about 70% beingused as aerosol propellants. Molina and Rowland did not antici-pate that ozone depletion would occur first in the Antarctic dueto annual polar stratospheric ice clouds and in the Arctic duringunusual winters. A simple schematic representation of the prin-cipal steps in stratospheric ozone depletion by halogen sourcegases is depicted in Figure 2.

Later in 1974, Molina and Rowland presented their findingsat a meeting of the American Chemical Society and held a pressconference warning that:

If CFC production rose at the then-current rate of 10percent a year until 1990, and then leveled off, up to50 percent of the ozone layer would be destroyed bythe year 2050. Even a 10 percent depletion, he said,could cause as many as 80,000 additional cases ofskin cancer each year in the United States alone,


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

along with genetic mutations, crop damage, andpossibly even drastic changes in the world’s climate.

If nothing was done in the next decade to preventfurther release of chlorofluorocarbons, the vastreservoir of the gases that would have built up inthe meantime would provide enough chlorine atomsto insure continuing destruction of the ozone layerfor much of the twenty-first century. They urged that

the use of the compounds as aerosol propellants bebanned. (Brodeur, 1986)

Ramanathan (1975) confirmed that CFCs are also powerful green-house gases, adding significantly to the scientific justification tocontrol CFCs (Ramanathan, 1975; Ramanathan et al., 1985).

1975 to 1985: Validating the Molina–Rowland ozonedepletion theory

Between 1975 and 1985, scientists debated but strongly sup-ported theMolina–Rowland theory of stratospheric ozone deple-tion, although estimates of likely ozone depletion from CFCsand other ODSs were far from certain. Molina and Rowlandpersisted in both their advocacy of ozone layer protection andin bolstering the scientific foundation and validating the hypoth-esis. For example, in 10 years between their original paper in1974 and the signing of the Vienna convention in 1985, Molinaand Rowland were co-authors on a dozen ozone science journalarticles and Mario Molina was co-author of 17 more. A smallnumber of professional science skeptics challenged the Molina–Rowland theory with both plausible and fanciful explanationsthat were eventually disproven (Oreskes and Conway, 2010).Before 1987, the aerosol products, refrigeration, and A/C indus-try questioned the science of stratospheric ozone depletion aslacking evidence to support the theory, and argued that CFCalternativeswould be flammable, toxic, and expensive. However,after the Montreal Protocol was signed in 1987, most industriesaccepted the theory and turned their attention to phase-out. Onemeasure of the strength of the stratospheric ozone science is thatafter the Montreal Protocol was signed in 1987, there was vir-tually no complaints or challenges to the science by industryassociations and business worldwide. The mid-1990s challengeby the U.S. pesticide industry questioning the ozone-depletionpotential (ODP) of methyl bromide was unsuccessful, as thescience was confirmed and the industry accepted the consensus(Parson, 2003).

In 1975, the National Academy of Sciences (NAS) andU.S. Department of Transportation concluded that nitrogen oxidesfrom SSTs were a threat but that atmospheric levels of chlorinefrom CFCs would deplete the ozone layer six times more effi-ciently than oxides of nitrogen from SSTs, and that ozone deple-tion would consequently increase the intensity of UV light atground level. The portion of the report covering environmentaleffects concluded that increases in ground-level UV light wouldadversely impact plant growth and animal health.

This report was the first integrated assessment of any envir-onmental risk and included the mandate to consider both climatechange and stratospheric ozone depletion. Six teams studied thecausal relationships from jet engine emissions to atmosphericimpacts, to environmental effects, and to social and economicconsequences. Agricultural economists predicted that shorten-ing of the frost-free growing season and increases in UV lightwould reduce agricultural yields (NRC, 1975).

Wofsy et al. (1975) confirmed Rowland and Molina’s scien-tific calculations:

Figure 2. The principal steps in the depletion of stratospheric ozone (Fahey andHegglin, 2011).


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

“Freons� [CFCs] are a potential source of strato-spheric chlorine and may indirectly cause seriousreductions in the concentration of ozone. . . .Allowing for reasonable growth in the Freon indus-try, ~10 percent per year, the reduction in ozonecould be 2 percent by 1980 and, if left unchecked,could grow to the disastrous level of 20 percent bythe year 2000.” Even if Freon� use were terminatedas early as 1990, “it could leave a significant effectwhich might endure for several hundred years.”(Wofsy et al., 1975)

The newly created U.S. Federal Interagency Task Force onInadvertent Modification of the Stratosphere heard testimonyfrom McElroy, who said that bromine and bromine com-pounds—including halons used in fire protection and methylbromide used in pest control and chlorobromomethane andn-propyl bromide uses as solvents and to manufacture plas-tics—appear “to be so effective at ozone depletion that [they]could be used as a weapon” (Sullivan, 1975).

The National Research Council of the National Academy ofSciences (NRC, 1976) summarized results of an expert panelthat examined existing atmospheric and laboratory measure-ments, as well as the mathematical models used to assess theimpact of such pollutants on stratospheric ozone and to makerecommendations on studies needed to improve understandingof the processes involved, concluding that “All the evidence thatwe examined indicates that the long-term release of CFC-11 andCFC-12 at present rates will cause an appreciable reduction inthe amount of stratospheric ozone.” Noting that CFCs wereproduced and used around the world, the NRC advised:

Clearly, although any action taken by the USA toregulate the production and use of CFMs (CFCs)would have a proportionate effect on the reductionin stratospheric ozone, such action must becomeworldwide to be effective in the long run. (Andersenand Sarma, 2002, p. 10)

In 1977 the United Nations Environment Programme (UNEP)established a Coordinating Committee on the Ozone Layer(CCOL) that included 13 industrialized countries, 3 developingcountries, 5 United Nations and international organizations, theEuropean Economic Community, the Organization forEconomic Cooperation and Development (OECD), theChemical Manufacturers Association, and the InternationalCouncil of Scientific Unions. Later, any interested country wasallowed to participate (Andersen and Sarma, 2002).

The CCOL met first in 1977 and yearly thereafter until 1986.The UNEP Ozone Layer Bulletins (1978 to 1985) recorded theconclusions of the world community on the science and environ-mental impacts of ozone depletion as they evolved, and providedthe basic input to the diplomatic negotiations that were initiatedin 1982. At each of its sessions, the committee examinedresearch results on stratospheric ozone depletion, and the healthand environmental impacts of depletion and the socioeconomicconsequences, and presented its reports to the GoverningCouncil meetings of UNEP and the negotiating groups.

The National Aeronautics and Space Administration (NASA)in October 1978 launched the Nimbus 7 satellite, and with it, twoinstruments that started to record ozone levels: the Total OzoneMapping Spectrometer (TOMS) and the Solar BackscatterUltraviolet (SBUV). The first TOMS provided data from 1978 to1993; the second, launched on a USSR Meteor 3 spacecraft,provided data from 1991 to 1994; the third, launched on theJapanese Advanced Earth Observing Satellite (ADEOS), provideddata from 1996 to 1997; and the fourth (Earth Probe TOMS)provided data from 1996 until 2006. The first SBUV operateduntil 1990; similar instruments have flown on several NationalOceanic and Atmospheric Administration (NOAA) satellites sincethen (Hoff and Christopher, 2009; Hidy et al., 2009).

In 1979, the NRC followed up its earlier findings with a reportby the Committee on Impacts of Stratospheric Change, and theCommittee on Alternatives for the Reduction of Chlorofluoro-carbon Emissions, which concluded that eventual ozone depletionwould be significant despite a temporary leveling off of global CFCemissions due to the U.S. ban on nonessential aerosol propellantuse (NRC, 1979).

Discovering and Measuring the AntarcticOzone “Hole”

In 1981, total ozone measurements from Japanese, British,and other Antarctic research stations using Dobson spectrophot-ometers recorded a 20% reduction in stratospheric ozone levelsin October above Antarctica. None of the Antarctic scientistspublished their 1981 results or consulted other stations to con-firm their observations. Joseph Farman, head of the GeophysicalUnit of the British Antarctic Survey, “could only assume thatsomething had gone wrong with his Halley Bay apparatus. Heknew, of course, about the Molina–Rowland theory and thescientific debate over the relationship between man-made che-micals and ozone depletion, but the Dobson reading was simplytoo low to suggest anything but an instrument malfunction”(Cagin and Dray, 1993). Furthermore, none of the scientistsconcerned about stratospheric ozone depletion had suspectedthat it would be evident first in the Antarctic, so they werelooking elsewhere for the first observational evidence.

In the Antarctic spring of 1982, low ozone levels were foundat the British Antarctic Survey and other stations. At the sametime, the ozone-measuring devices aboard the Nimbus 7 satellitehad also registered low ozone levels. Again, none of theAntarctic ground stations or satellite scientists published theobservations of ozone depletion and none raised alarm amongcolleagues, perhaps because the low values had not yet beenlinked to CFCs in the atmosphere.

In 1982, the NRC (1983) concluded that squamous-cell skincancer could be doubled if CFC production were increased atprevailing growth rates (NRC, 1982) and in 1983 it concludedthat “most plants, including crop plants, are adversely affectedby UV-B radiation. Such irradiance stunts growth, cuts downtotal leaf area, reduces production of dry matter, and inhibitsphotosynthesis in several ways.”

Chubachi (1984) of the Japanese Meteorological ResearchInstitute in Ibaraki was first to report seasonal ozone depletion


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

over Antarctica, but Chubachi and his colleagues failed toappreciate the significance of their findings and took no actionsto bring them to the attention of policymakers. Because activistscientists more directly involved in policy on stratospheric ozonehad not anticipated the Antarctic ozone hole, they were notcarefully monitoring the Antarctic reports.

Estimates of future worldwide ozone depletion continued tovary. Prather et al. (1984) concluded that an increase in theconcentration of inorganic chlorine in the stratosphere could“cause a significant change in the chemistry of the lower strato-sphere leading to a reduction potentially larger than 15 percent inthe column density of ozone. This could occur, for example, bythe middle of the next century, if emissions of man-made chlor-ocarbons were to grow at a rate of 3 percent per year.”

In May 1985, scientists from the British Antarctic Survey(Farman et al., 1985) sounded the alarm that ozone levelsabove Antarctica had been significantly depleted everyAntarctic spring since at least 1981. Although their own researchand the research of other scientists had no proof of causation,their warning went beyond the evidence and attributed theAntarctic ozone depletion to CFCs. Joseph C. Farman wasquick to organize news conferences and interviews, explainingthe significance of ozone depletion and confidently putting theblame on CFCs (Pearce, 2008; Brysse, 2009).

The phenomenon of ozone depletion over Antarctica quicklybecame known as the “ozone hole,” a phrase first used in pub-lished media accounts by Rowland, and was frequently illu-strated with images created by NASA that depicted levels ofreduced column ozone amounts that appeared as circular regionscentered near and around the South Pole.

Seven international agencies teamed up in 1985 to write anassessment of the “state of the ozone layer” (NASA et al., 1985).The chemicals of interest to the agencies were NOx from sub-sonic and supersonic aircraft; nitrous oxide from agriculturalpractices and energy production; chlorofluorocarbons used asaerosol propellants, foam-blowing agents, solvents, and refrig-erants; brominated compounds, including halons used to extin-guish fires and suppress explosions; carbon monoxide andcarbon dioxide from combustion processes; and CH4 from avariety of sources, including natural and agricultural wetlands,tundra, biomass burning, and enteric fermentation in ruminants.“It is now clear that these same gases are also important in theclimate issue,” the report concluded.

The report warned that if there were a doubling of the 1985CFC release rate, “the one-dimensional models predict that therewill be 3 percent to 12 percent reduction of the ozone column,regardless of realistically expected increases in carbon dioxide,nitrous oxide, and methane.”

Solomon et al. (1986) concluded that the “remarkable deple-tions in the total atmospheric ozone content in Antarctica . . . arelargely confined to the region from about 10 to 20 km, during theperiod August to October.” They suggested that chlorine com-pounds might react on the surfaces of polar stratospheric clouds,providing a reaction site for heterogeneous reactions that couldgreatly accelerate ozone loss in the Antarctic lower stratosphere:

A unique feature of the Antarctic lower stratosphereis its high frequency of polar stratospheric clouds,

providing a reaction site for heterogeneous reac-tions. A heterogeneous reaction between HCl andClONO2 is explored as a possible mechanism toexplain the ozone observations. This process pro-duces changes in ozone that are consistent with theobservations, and its implications for the behaviourof HNO3 and NO2 in the Antarctic stratosphere areconsistent with observations of those species there,providing an important check on the proposedmechanism. (Solomon et al., 1986, p. 755)

In August 1986, four teams of U.S. researchers arrived inAntarctica as part of the first National Ozone Expedition to studythe ozone hole over Antarctica. The NOAA AeronomyLaboratory team, led by Solomon, made ground-based visibleabsorption measurements; the University of Wyoming team, ledby David Hofmann, carried out balloon-based ozone and aerosolparticle measurements; the State University of New York atStony Brook team, led by Robert de Zafra, made ground-basedmicrowave emission measurements; and the Jet PropulsionLaboratory team, led by Crofton Farmer, made ground-basedsolar infrared absorption measurements. All four of the teamssuccessfully measured the formation and strengthening of theozone hole, confirming the phenomenon. Their measurementsand findings, according to NASA, strongly suggested that “per-turbed chlorine chemistry was involved.” But there was still noconclusive proof that chlorine was to blame for the ozone hole,whether the hole was a natural phenomenon having to do withchanges in temperature and air circulation, or whether it wascaused by chlorine compounds contributed by man-made che-micals. (NASA, 1996).

Two months later, in October 1986, NASA formed anInternational Ozone Trends Panel in collaboration with UNEP,the U.S. Federal Aviation Administration (FAA), NOAA, andWMO. The panel was a response to “two important reports ofchanges in the atmospheric ozone” that occurred in 1985. “Thefirst report was of a large, sudden, and unanticipated decrease inthe abundance of springtime Antarctic ozone over the last dec-ade. The second report, based on satellite data, was of largeglobal-scale decreases since 1979 in both the total column con-tent of ozone and in its concentration near 50 km altitude”(NASA et al., 1988, p. 3).

The NASA (1996) Airborne Antarctic Ozone Experiment“determined that the cause of the Antarctic ozone hole waschlorine chemistry. Large quantities of chlorine monoxide werefound which were co-located with areas of ozone depletion. Theaerosol data gathered was consistent with processing on polarstratospheric clouds. But the theories which said that it was anatural phenomenon due to atmospheric dynamics were found tobe inconsistent with the new data.” The experiment’s datashowed an inverse correlation between ozone and chlorine mon-oxide, according to NASA:

Because chlorine monoxide is produced by the pro-cess in which man-made chlorine destroys ozone,the large quantities observed provide strong evi-dence that man-made chemicals are involved in theAntarctic ozone loss process. . . . The data obtained


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

during the Antarctic mission show[ed] the lowestozone levels ever recorded and directly implicate[d]man-made chemical compounds, chlorofluorocar-bons, in the enormous ozone loss over this remoteregion in the Southern Hemisphere. (NASA et al.,1996)

Health and agricultural scientists strengthen findings

In April 1987, Margaret Kripke, a skin cancer expert at theUniversity of Texas, told the U.S. White House Domestic PolicyCouncil that although ozone depletion was expected to increasethe number of skin cancers, there were other impacts with fargreater global consequences, particularly the potential impact onthe global food supply and the human diseases due to the effectsof UV radiation on the human immune systems (Cagin and Dray,1993).

At a U.S. Senate hearing in May 1987, Alan Teramura of theUniversity of Maryland testified that the potential of UV radia-tion to damage crops and plants was indisputable (Cagin andDray, 1993).

Signing and strengthening the Montreal Protocol andits Vienna Convention

In March 1985, 34 countries agreed on the ViennaConvention for the Protection of the Ozone Layer, which estab-lished the framework for a protocol. The obligations of theparties to the convention were to cooperate in research, observa-tions, and information exchange, and to adopt policies to controlhuman activities that might modify the ozone layer. The onlymention of CFCs came in Annex 1 as one of the many substances“thought to have the potential to modify the chemical and phy-sical properties of the ozone layer” (Benedick, 1998; Andersenand Sarma, 2002; Parson and Greene, 1995; Young, 1999;Parson, 2003).

During 14–16 September 1987, a conference of the UnitedNations Environment Programme Plenipotentiaries created theMontreal Protocol on Substances that Deplete the Ozone Layer,which was signed at that meeting by 24 countries and theEuropean Economic Community (Weisskopf, 1987).

Subsequently, the Montreal Protocol’s internal assessmentpanels provided the scientific basis for the necessity of strength-ening of the Montreal Protocol and the technical and economicbasis for scheduling the phase-out for each group of ODSs. It issignificant that the Montreal Protocol assessments were first tobring to the attention of the parties many of the opportunities tostrengthen ozone layer protection and to avoid regulatory trainwrecks. For example, it was the Scientific Assessment Panel(SAP) that highlighted the importance of controlling methylbromide, bromochloromethane, n-propyl bromide, and nitrousoxide (only n-propyl bromide and nitrous oxide are still uncon-trolled), and it was the Montreal Protocal Technology andEconomic Assessment Panel (TEAP) that recommended earlyhalon phase-out to avoid overproduction, recommended collec-tion and destruction of ODS contained in products, and crafted

and advised on Essential Use Exemptions and Critical UseExemptions that allow continued use after phase-out for applica-tions considered important to parties (Andersen and Sarma,2002; Andersen et al. 2007). Summaries of annual assessmentsand associated Amendments and Adjustments, showing steadyprogress in the evolution of the protocol, the science and under-standing of ODSs, and the positive results of their control can befound in the supplementary materials online.

1998–1999: The Intergovernmental Panel on Climate Change(IPCC) and TEAP first cooperation. “Because changes in ozoneaffect the Earth’s climate and changes in temperature, green-house gases and climate affect the ozone layer” and “becauseHFCs included in the basket of gases of the Kyoto Protocol(CO2, CH4, N2O, PFCs, and SF6) are significant substitutes forsome ODSs controlled under the Montreal Protocol” andbecause the choice of alternatives and substitutes for ODSs“may significantly influence energy usage” (UNEP, 1999),IPCC/TEAP concluded that Life Cycle Climate Performance(LCCP) is the comprehensive metric for judging the impacts ofODS substitution, that the Kyoto Protocol need not interfere withthe Montreal Protocol provided that HFC were available toreplace ODSs where other options are not viable, and that theMontreal Protocol need not interfere with the Kyoto Protocolprovided that implementation of the Montreal Protocol avoidedHFCs where other viable alternatives to ODSs are available(UNEP, 1999).

2005: IPCC/TEAP Safeguarding the ozone layer and the globalclimate system. “Safeguarding the Ozone Layer and the GlobalClimate System” (IPCC, 2005) was far more comprehensive anddetailed than the 1999 IPCC/TEAP and TEAP task force reports.It made significant progress in:(1) Providing the atmospheric scientific framework for choos-

ing alternatives and substitutes to ODSs, including the stra-tospheric chemistry and dynamics and their coupling toclimate change, the radiative forcing of the relevant ODS,HFC, and other gases, and their roles in tropospheric chem-istry and air quality.

(2) Collecting available data on historic and ongoing specificODS and HFC production; estimating the annual use andemissions by sector and application, and the inventory ofODS and HFCs carried forward in chemical inventory andcontained in refrigeration, air conditioning, and fire protec-tion products; and reconciling top-down observations ofODS and HFC concentrations in the atmosphere andbottom-up estimates of annual ODS and HFC emissions.

(3) Summarizing available methodologies to characterize orcompare the environmental performance of alternativesand substitutes for refrigeration, air conditioning, and ther-mal insulating foam, including total equivalent warmingimpact (TEWI) and life-cycle climate performance (LCCP).

(4) Describing technical options to ODSs HFCs, and PFCs,including consideration of process improvements in applica-tions, improved containment, recovery and recycling duringoperation, servicing, and end-of-life, and including detailed


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

consideration of technical performance, environmentalhealth and safety, cost and availability, and total energyand resource efficiency.

2007: Estimates of the importance of the Montreal Protocol forclimate protection. Velders et al. (2007) quantified the carbon-equivalent climate forcing that was avoided by the phase-out ofozone-depleting greenhouse gases, considering (1) time-dependent scenarios of annual ODS production, emissions, con-centrations, and associated radiative forcing; (2) the time depen-dence of CO2 emissions and associated radiative forcing; and (3)the offsets of climate protection by ODSs caused by stratosphericozone depletion and the use of ODS substitute gases.

Radiative forcing is the difference between the incoming solarradiation energy reaching the earth and the outgoing thermalradiation energy in a given climate system. The impact of GHGemissions in the atmosphere is to “trap” outgoing thermal radia-tion and therefore increase the earth’s temperature. The increasein atmospheric GHG concentrations since the industrial revolu-tion has resulted in an unbalanced climatic system with constantincreases in radiative forcing due to such emissions.

The Velders study estimated that the climate benefits ofactions under the Montreal Protocol in 2010 is about 11 giga-tonnes CO2-equivalent per year, which is 5–6 times the reductiontarget of the first commitment period (2008–2012) of the KyotoProtocol, as illustrated in Figure 3. The Montreal Protocol netreduction in ODS radiative forcing in 2010 is equivalent to about7–12 years of growth in radiative forcing of CO2 from humanactivities. In addition, the study estimated that it is technicallyfeasible to further protect the ozone layer while reducing globalGHG emissions by up to 5% for 10 years or more throughcollection and destruction of surplus or contaminated ODS, byan acceleration of the HCFC phase-out in developed countries,by adoption of technologies that are both ozone and climate safewherever feasible, and by accelerated ODS phase-out in devel-oping countries.

The findings of the Velders science team energized diplomatsto use the Montreal Protocol to protect the climate by accelerat-ing the phase-out of HCFCs, mindful that an earlier phase-outwould also further protect the climate (Andersen et al., 2007). Asa consequence, in 2007 the parties amended the MontrealProtocol to accelerate the HCFC phase-out in both developedand developing countries. The dramatic effect of the MontrealProtocol and its subsequent amendments is shown in Figure 4.

Protecting the stratospheric ozone layer also benefitsglobal climate

Periodically, teams of scientists make updated estimates of thepossible consequences if ODS production and consumption hadincreased at annual rates of 3–5%, rather than being phased out(Morgenstern et al., 2008):

Nearly two-thirds of Earth’s [stratospheric] ozone isgone—not just over the poles, but everywhere. Theinfamous ozone hole over Antarctica, first discoveredin the 1980s, is a year-round fixture, with a twin overthe North Pole. The ultraviolet (UV) radiation falling

onmid-latitude cities likeWashington, D.C., is strongenough to cause sunburn in just five minutes. DNA-mutating UV radiation is up more than 500 percent,with likely harmful effects on plants, animals, andhuman skin cancer rates. (NASA, 2009, p. 1)

Radiative forcing from the combined effects of carbon dioxide,ODSs, other non-CO2 greenhouse gases and black carbon wouldhave already pushed the climate past the temperatures that wouldmelt glaciers and sea ice causing drastic sea level rise, increasethe incidence of violent storms, release methane greenhousegases from previously frozen soils, and further warming theEarth by solar absorption on land and water surfaces that aredarker than when covered with snow and ice. (UNEP andWMO,2011)

The benefits of ozone layer protection far exceeded the globalcosts (Doniger, 1988; Dudek et al., 1990; DeCanio and Lee,1991), and many companies phased out far more rapidly thanrequired by the Montreal Protocol and often at a lower cost thanoriginally projected by industry and government alike (Millerand Mintzer, 1986; Cook, 1996; Le Prestre et al., 1998;Andersen and Sarma, 2002; Andersen et al., 2007):

By the year 2165, actions to protect and restore theozone layer will save an estimated 6.3 million

Figure 3. CO2-equivalent emissions under various scenarios. The red linerepresents historic and predicted future global CO2 emissions. The green arearepresents the CO2-eq of ODS emissions that would have occurred if Molina andRowland had not warned the world about CFCs (could have been greater thanCO2!). The blue area represents the CO2-eq of ODS emissions without theMontreal Protocol. The area below the blue line represents the total climateprotection provided by the Montreal Protocol, estimated at ~11 Gt CO2-eq(Velders et al., 2007). The black line is the actual CO2-eq ODS emissions asreduced by the Montreal Protocol.


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

U.S. lives that would have otherwise been lost to skincancer ... [and] will produce an estimated $4.2 trillionin societal health benefits in the United States overthe period 1990 to 2165. (U.S. EPA, 2007, p. 2)

The stratosphere and climate have been protected from ODSemissions but global temperature increase from greenhouse gasemissions continues, with inclusion of growing contributionfrom HFCs, which are being used to replace the ozone-depletingrefrigerants and foam-blowing agents being phased out by theMontreal Protocol. Emissions of HFCs are now the fastest grow-ing of all greenhouse pollutants in the United States and in manyother countries (NOAA et al., 2011). Scientists have calculatedthat even under the most conservative assumptions of the growthin population and income, climate forcing from projected HFCemissions is likely to exceed the climate-protecting benefits ofthe ODS phase-out by mid-century (Velders et al., 2012). Theradiative forcing of HFC emissions could contribute as much as20% of that from CO2 by 2050 if CO2 emissions continue alongbusiness-as-usual projections, and equal up to 40% if CO2 isconstrained to a 450 ppm scenario (UNEP, 2011a). Furthermore,scientists are unsure of the combined impacts of atmosphericfeedback from projected changes in the atmosphere composi-tion, such as colder stratospheric and warmer tropospheric tem-peratures; accelerated atmospheric circulation; warming andshifting surface wind, water, and storm tracks on the AntarcticPeninsula and Southern Ocean; and global ozone above its“natural state” as a consequence of increasing greenhousegases (Forster et al., 2007).

Governments have proposed to take action both to preservethe climate benefits achieved by the Montreal Protocol and toleverage those benefits by phasing down the HFCs that replacedODSs and replacing them with chemicals that have low globalwarming potentials (GWP) and are energy efficient. Every yearsince 2009, the Federated States of Micronesia have proposed anAmendment to the Montreal Protocol to phase down high-GWPHFCs, with the United States, Canada, and Mexico offeringsimilar amendments since 2010 (UNEP, 2012b, 2012c, 2013,2013a). As shown in Figure 5, both the Micronesian and NorthAmerican proposals would reduce HFC production and con-sumption 85–90%, providing climate mitigation of 87–146 GtCO2-eq. by 2050 (Figure 5) (Velders et al., 2009; Molina et al.,2009; Velders et al., 2012; Zaelke et al., 2012).

Support for a phase-down of HFCs under the MontrealProtocol is steadily growing. In the Rio þ 20 declaration, TheFuture We Want, more than 100 heads of state recognized theclimate damage from HFCs and called for the gradual phase-down of their production and consumption (UN, 2012). In addi-tion, by the time of its closing in 2012, 108 countries had joinedthe Bangkok Declaration calling for the use of low-GWP alter-natives to CFCs and HCFCs (UNEP, 2011). Through November2012, 105 parties had provided written support to the BaliDeclaration on Transitioning to Low Global Warming PotentialAlternatives to Ozone Depleting Substances (UNEP, 2012d).

Many national governments are already taking action onHFCs outside of the Montreal Protocol, including developingnational inventories of new and old equipment utilizing HFCs,

Figure 4. Effect of the Montreal Protocol and subsequent amendments onstratospheric chlorine levels (Fahey and Hegglin, 2011).

Figure 5. Cumulative decrease of direct GWP-weighted emissions of HFCsunder the proposed Micronesian and North American Amendments to theMontreal Protocol.


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

implementing mandatory refrigerant leakage checks for refrig-eration and air conditioning equipment, and establishing produ-cer responsibility schemes requiring producers and suppliers ofHFCs to take back recovered bulk HFCs for further recycling,reclamation, and destruction (Schwarz et al., 2011). Privatecompanies are also taking voluntary action to limit their use ofHFCs. The Consumer Goods Forum, a global network of morethan 650 retailers, manufacturers, service providers, and otherstakeholders from more than 70 countries, has pledged to beginphasing out HFCs in new equipment beginning in 2015 (CGF,2012). A global partnership of companies made up of Coca-Cola, McDonalds, Pepsico, Red Bull, and Unilever, and sup-ported by Greenpeace and UNEP, has pledged to phase out thepurchase of new HFC equipment on accelerated schedules asnew technology is commercialized (Refrigerants, Naturally!,2012).

Attenuating the growth in HFCs is a component of anycomprehensive climate change mitigation strategy to limit tem-perature projected rise to below 2�C over preindustrial tempera-tures, the goal of international climate negotiations. Rapidreductions in a group of short-lived climate pollutants (SLCP)including black carbon soot (BC), CH4, tropospheric ozone, andHFCs can help limit global peak temperature when combinedwith necessary reductions to CO2 (Ramanathan and Xu, 2010;UNEP and WMO, 2011; Shindell et al., 2012; IGSD, 2013).These four climate pollutants are known as SLCPs because oftheir relatively shorter atmospheric lifetimes compared to CO2,approximately 25% of which remains in the atmosphere formillennia (Solomon et al., 2007). BC remains in the atmospherefor weeks, CH4 for approximately 12 years, tropospheric ozonefor hours to days, and the average atmospheric lifetime of thecurrent mix of HFCs by weight is 15 years (Zaelke et al., 2012;Velders et al., 2012).

The rapid combined mitigation of all four SLCPs can avoid asmuch as 0.6�C of additional warming by midcentury, with themitigation of HFCs contributing an estimated 17% of theavoided warming by 2050 (Ramanathan and Xu, 2010). Thiswould cut the estimated current rate of global warming by half,and the rate of warming in the Arctic, which has warmed at twicethe global average since 1980, by two-thirds (UNEP and WMO,2011; AMAP, 2011; Hu et al., 2013). These studies show thatfast action to reduce these major climate forcers can potentiallyforestall some of the worst predicted impacts of climate change.

Unfortunately, human emissions of greenhouse gases, aero-sols, and BC are moving in thewrong direction. According to theWMO, the atmospheric concentration of CO2, the most impor-tant greenhouse gas, reached 390.9 ppm in 2011, or 140% of thepreindustrial level of 280 ppm (WMO, 2012). Climate modelsindicate that limiting global temperatures below 2�C will requirelimiting the atmospheric concentration of CO2 to 450 ppm orless by 2100 (Meinshausen et al., 2009; Luderer, 2012).Emissions of CH4 from human activities increased atmosphericconcentrations to a new high of about 1813 parts per billion(ppb) in 2011, or 259% of the preindustrial levels (WMO, 2012).If left unchecked, emissions of CH4 may increase by as much as40% by 2030 (Ramanathan and Xu, 2010). Emissions of BC, thesecond most powerful anthropogenic climate forcer behind CO2,are also rising (Bond et al., 2013; U.S. EPA, 2012). In 1996,

global emissions of BC were estimated at 8.0 million tonnes, androse to 8.4Mt by 2000. BC emissions are expected to increase by15% by 2015 (WMO, 2012). N2O, which is long-lived in theatmosphere and not included in the preceding analysis, is apowerful greenhouse gas whose atmospheric concentrationsreached approximately 324 ppb in 2011, 1 ppb above the pre-vious year and 120% of the preindustrial level. N2O also depletesstratospheric ozone (WMO, 2012).

Technical, Health, and EnvironmentalHistory of Refrigeration and AirConditioning

After a brief summary to put this section into perspective andshow its relationship to theMontreal Protocol, a historical reviewof refrigeration and air conditioning throughout the ages isprovided. This is followed by the case history of one specificapplication, the development and barriers encountered in mobileair conditioning.

This section presents an abbreviated history of six distinctmarket transformations in refrigeration and A/C that were dri-ven by scientific concern for health and environment and, in thecase of ODSs, by the Montreal Protocol and national imple-mentation in all countries. It includes a discussion of the latestmarket transformation to protect climate, which is just gettingunderway.

The six market transformations are: (1) from primitive refrig-eration to global markets for harvested ice; (2) from harvested iceto manufactured ice using toxic and flammable refrigerants; (3)from point-of-use ice to distributed mechanical refrigeration,still using toxic and flammable refrigerants; (4) from toxic andflammable refrigerants to CFCs that are ozone-depleting green-house gases; (5) from ozone-depleting greenhouse gas refriger-ants to ozone-safe greenhouse gases; and (6) from greenhousegas refrigerants to climate-safe refrigerants with near-zero emis-sions and high energy efficiency (Nagengast, 1988; Donaldsonand Nagengast, 1994; Harry, 1999; Calm 2012). The six transi-tions overlap to different degrees within and between countriesdue to differences in regulatory mandates, wealth, cost of andaccess to new technology, and other factors.

The first three transitions were driven by an improved under-standing of the health and economic benefits of cold storage forfood. Safety concerns, such as flammability and toxicity, weregenerally viewed as an acceptable trade-off for improvements infood safety and security. Details are found in the next section.

The fourth refrigerant transition, after 1930 to CFCs, wasdriven by the apparent safety and health advantages of CFCs, alack of understanding of the ozone depletion and climate changerisks, and the competitive cost of the refrigerant. However,history has shown that the transition to CFCs would havedestroyed the stratospheric ozone layer and altered the climateif scientific warnings had been as little as 25 years later or if thepublic and policymakers had acted less quickly to initiate whatbecame the fifth transition. This might be considered the firstmajor unintended consequence of what “seemed a good idea atthe time,” which it truly was.


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

The fifth refrigerant transition, away from ozone-depletinggreenhouse gas refrigerants (such as CFCs) to ozone-safe green-house gases (primarily HFCs, with temporary use of HCFCswhere other options were not available), was undertaken despiteuncertainty in both the atmospheric science and the availabilityof new technology. Heeding the early scientific warnings aboutthe effect of CFCs on the stratospheric ozone layer, policymakersacted quickly to implement domestic control measures and beginglobal treaty negotiations. This is noteworthy because a delay ofas little as 25 years theoretically would have destroyed the strato-spheric ozone layer and altered climate, as discussed in detailearlier in this review.

The science would have been delayed by at least 25 years (1)if ozone monitoring stations had not been part of the 1957Geophysical Year initiatives; (2) if the U.S. NASA and otherspace agencies had not placed earth monitoring satellites in orbit;and (3) if Mario Molina and Sherwood Rowland had been lessconfident in their science or less persistent in their politicalactivism. The U.S. ozone monitoring satellite that was criticalto proving ozone depletion was placed in orbit by a Soviet rocketafter U.S. scientists lost access to space as a consequence of the2½-year grounding of the Space Shuttle fleet after theChallenger exploded during launch in January 1986. The offerby the USSR to transport the U.S. satellite to orbit was promptedby a sense of urgency during the diplomatic negotiations leadingup to the Montreal Protocol agreement (Khattatov, 2002).

In order to provide guidance to the reader, Table 2 lists themajor chemicals used as automotive refrigerants in the currentmarket and some relevant properties.

While the aforementioned transitions, away from CFCs,averted the high risk of destruction of stratospheric ozone andcontributed to climate protection with lower GWP refrigerantsand higher energy efficiency, the climate forcing of the substi-tutes proved too large, particularly because emissions of CO2

and other major climate forcers have not been reduced. Thegreatest emphasis was on immediate phase-out of CFCs, andtheir quick replacement with substitutes that were cost-competitive, easy to manufacture, and that could be substitutedwith minimal technical changes to existing equipment.

The sixth refrigerant transition, which is just getting under-way, seeks to phase down the production and consumption ofHFCs and replace them with climate- and ozone-safe energyefficient alternatives. HFCs are the greenhouse refrigerantsmost commonly used as ozone-friendly replacements for CFCsand HCFCs. A phase-down in HFCs would provide climatemitigation—up to 146 billion tonnes of CO2-eq reductions by2050 (Velders et al., 2009; Velders et al., 2007). Additionalclimate mitigation would also be realized through avoidedgrowth in electricity use because refrigeration and A/C systemsusing low-GWP alternatives to HFCs are able to achieve equal orsuperior energy efficiency (up to 30% improvements) over thosecurrently employing HFCs (Schwarz et al., 2011).

Fast action on the prevention of increasing use and emissionsof HFCs and reduction of other SLCPs, such as BC, CH4, andtropospheric ozone, can cut the rate of global warming in half forthe next several decades. Action to address SLCPs can also cutthe rate of warming over the elevated regions of the Himalayan–Tibetan Plateau by at least half and reduce the rate of warming in

the Arctic by two-thirds over the next 30 years, while reducinghealth and ecological risks (UNEP and WMO, 2011). Despitethe projected benefits of an HFC phase-down, success withreducing CO2 emissions is also necessary to have a reasonableprobability of limiting global temperate rise to 2�C comparedwith preindustrial levels through 2100 (Ramanathan and Xu,2010).

Brief history of air conditioning and refrigeration,prehistoric to 1800s

Simple air conditioning was achieved in ancient cultures witha variety of innovative techniques:. Egyptians cooled roomsusing flowing cold water or evaporating water on porous sur-faces. Romans circulated cold water from aqueducts throughwalls. Persiana and Indiana used cisterns and passive windtowers, and Chinese used manual- and water-powered rotaryfans with evaporative fountains to cool indoor spaces(Needham, 1991). In the 17th century, Cornelis Drebbel “turnedSummer intoWinter” for King James I of England by adding saltto water and ice (Laszlo, 2001). In the summer of 1881, a fan andice system (200 kg ice per hour) cooled U.S. President JamesA. Garfield (Billings, 1893; Nagengast, 1999). Air conditioning,even as simple as cold towels and ice packs, was recognized forthe health and medical benefits in treating heat exhaustion andreducing core body temperature from fevers.

From prehistoric times, refrigeration of perishable foods hasbeen accomplished in caves, cellars, wells, and artesian “spring-houses.” As indicated in Table 3, natural ice and snow werecollected locally or brought down from nearby mountains andstored in pits or insulated chambers for warm-weather use. In themid-1500s, food and wine were refrigerated in containers placedin water baths cooled by adding chemicals such as sodium nitrateand potassium nitrate. In the 1600s, wine was cooled usingrotating bottles in water with dissolved saltpeter.

1800 to 1900: Harvested ice replaced withmanufactured ice and mechanical on-site refrigerationfor breweries and meat packing plants

In the first half of the 1800s, American Frederick Tudorinvented insulated ice storage and American Nathaniel Wyethinvented tools and methods for efficiently cutting uniformblocks of ice from frozen ponds. These inventions facilitatedthe large-scale shipment of ice globally on sailing ships. In the1840s rail cars refrigerated with ice were used to transport milkand butter and seafood by 1860. In 1867, AmericanJ. B. Sutherland patented the first railroad car refrigerated byice that controlled temperature by adjusting the amount of airpassing over ice and placing products requiring the coldesttemperatures nearest the ice. During this time period, ice marketsheld their own while engineers struggled to make mechanicalrefrigeration reliable and safe.

In 1748, William Cullen of Scotland first demonstrated thebasic method of mechanical refrigeration by boiling diethyl etherin a partial vacuum, which absorbed heat from the surroundingair. In 1758, American Benjamin Franklin and Britain John


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

Hadley produced freezing temperatures by evaporating highlyvolatile liquids such as alcohol and ether (Franklin, 1758). In1805, American Oliver Evans described, but did not build, thefirst mechanical refrigeration equipment designed to compress arefrigerant, expanding it in an “evaporator coil” and then dischar-ging the heat in a second heat exchanger before the refrigerant wasrecompressed and recirculated. In 1820, the British scientistMichael Faraday invented a machine based on the Evans designthat achieved cooling by evaporating ammonia and other gasesthat had been compressed and liquefied. In 1834, Jacob Perkinsbuilt a working refrigeration system and obtained the first vapor-compression refrigeration patent. In 1842, American physicianJohn Gorrie demonstrated a closed-cycle compressor technologysimilar to the machine invented by Oliver Evans to create ice thathe used to cool yellow fever patients being treated in a Floridahospital. Gorrie was granted a patent in 1851 (Gladstone, 1998).

American Alexander C. Twinning obtained patents in 1850and 1853 and was the first to profitably commercialize refriger-ant equipment for the brewing and meatpacking industriesbeginning in 1856. In 1854, Australian James Harrison con-structed a large-scale vapor-compressor ice-making machine

using ether, which was granted a patent in 1855. He built numer-ous commercial systems in the 1860s and beyond. In 1859,Ferdinand Carré of France commercialized a more complexsystem for brewing and meatpacking applications using ammo-nia, which has the advantage of higher cooling capacity as aresult of its low boiling temperature. In 1866, T. C. Lone madethe first recorded use of CO2 as a refrigerant, and in the 1870sS. Liebmann’s Sons Brewing Company in Brooklyn, New York,first used absorption refrigeration. In 1876, German engineerCarl P. G. Linde patented the process of liquefying gas that is partof basic vapor-compression refrigeration technology.

In 1882, William Soltau Davidson fitted a compressionrefrigeration unit to the New Zealand vessel Dunedin, whichshipped meat and dairy products from Australasia and SouthAmerica. In 1886 John Hall of Dartford, England, outfitted theSS Selembria with a vapor compression system to bring muttonto market from the Falkland Islands (Palmer, 1973; J & E HallInternational, 2012). Refrigerated rail and ocean shipping facili-tated the globalization of meat and dairy markets, bringing highprofits to producers in remote locations with low productioncosts but insufficient wealthy local customers.

Table 2. Mobile air conditioning refrigerants discussed in this review

Chemical Name Type Status ODP*

GWP**(100years) Comments

CFC-12 Dichlorodifluoromethane CFC ProductionhaltedJanuary 1,1996

1 10,900 Original CFC; Manufactureprohibited underMontreal Protocol

HFC-134a 1,1,1,2-Tetrafluoroethane HCFC Current MACrefrigerant

0 1430 Adopted worldwide as CFC-12 substitute

HFC-152a 1,1-Difluoroethane HCFC Use as MACrefrigerantpermitted

0 124 Flammable refrigerant butcan be used in secondaryloop system

CO2 Carbon Dioxide CO2 Use as MACrefrigerantpermittedby USEPA

NA 1 Supported by somemanufacturers as MACrefrigerant; high pressureand toxicity problems

HFO-1234yf 2,3,3,3-Tetrafluoropropene

HFO Industrychoice toreplaceHFC-134a

0 4 Recently adopted by mostmanufacturers worldwideto replace HFC-134aRefrigerant

HCC-40 Chloromethane(Methyl chloride)

Chlorinatedhydrocarbon

Illegallyused withHFC-134a

0.02 16 Poisonous and dangerous;corrupting worldwidesupply of refrigerant

HCO-290 Propane Hydrocarbon Illegal to useas MACrefrigerant

0 <5 Flammable; used byunscrupulous shops whenservicing HFC-134asystems

Notes: *The ODP is the ratio of the impact on ozone of a chemical compared to the impact of a similar mass of CFC-11 (trichlorofluoromethane). Thus, the ODP ofCFC-11 is defined to be 1.0. Other CFCs and HCFCs have ODPs that range from 0.01 to 1.0. **The definition of a GWP for a particular greenhouse gas is the ratioof heat trapped by one unit mass of the greenhouse gas to that of one unit mass of CO2 over a specified time period.


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

Tab

le3.

History

ofrefrigerationandairconditioning

Refrigeratio

nUntil1850

1850–19

3019

30–19

90s

1990–20

10s

Beyon

d20

10s

Industrial

Harvested

iceandsnow

SO2,ethers,NH3,C

O2,hyd

rocarbon

s,

methylchloride

SO2,N

H3,hyd

rocarbon

s,CFCs,

HCFCs

SO2,N

H3,hyd

rocarbons,

HFCs

SO2,N

H3,hyd

rocarbon

s,

low-G

WPHFCs

Com

mercial

Harvested

iceandsnow

SO2,ethers,NH3,m

ethylchloride,

andinfrequently

Methylb

romide,

carbon

tetrachloride

CFCs,HCFCs

HFCs,NH3,C

O2,

hydrocarbo

ns,

NH3,C

O2,hyd

rocarbon

s,

low-G

WPHFCs

Residential

SO2,ethers,NH3,

CFCs,HCFCs

HFCs,hydrocarbo

nsHyd

rocarbon

s

Aircond

itioning

Until19

1019

10–19

3019

30–19

90s

1990–20

10s

Beyon

d20

10s

Industrial

Shading,n

aturalventilatio

n,fans,

evaporation

SO2,ethers,NH3

CFCs,HCFCs

NH3,hyd

rocarbon

s,HFCs

NH3,hyd

rocarbons,

HFCs

Com

mercial

SO2,ethers,NH3,

CFCs,HCFCs

HFCs,NH3,C

O2,

hydrocarbo

ns,

NH3,C

O2,low

-GWP

HFCs

Residential

None

CFCs,HCFCs

HFCs

Low

GWPHFCs,

hydrocarbo

ns

Mob

ileAC

Non

eNon

eHCFCs,CFCs

HFCs

Low

-GWPHFCs,CO2


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

By the 1890s, nearly every large brewery and meat packingplant was equipped with refrigeration machines, typically usingtoxic and flammable refrigerants. Air conditioning found earlyapplications in hospitals, dining rooms, theatres, print shops,office buildings, retail stores, and schools.

In addition, harvested ice became a health problem becausemost rivers and lakes were increasingly contaminated withhuman sewage, agricultural waste, and chemical pollution. Thesolution to contaminated harvested ice was to manufacture iceusing mechanical refrigeration from pure water sources, whichalso had the advantage of “just-in-time” production and no riskof a warm winter or a hot summer unbalancing the supply anddemand for ice. However, there were substantial worker safetyrisks associated with mechanical refrigeration, including acci-dents caused by flammable and toxic refrigerants, resulting ininjury and sometimes death. Toxic, nonflammable methyl bro-mide and carbon tetrachloride, although infrequently used asrefrigerants, were eventually discovered to be potent ozone-depleting substances (ODSs) and were later controlled by theMontreal Protocol.

1900 to 1930: Ice competes with mechanicalrefrigeration using toxic and flammable refrigerants

From about 1900 until the 1930s, the use of toxic and flam-mable refrigerants, primarily sulfur dioxide, ethers, ammonia,and hydrocarbons (isobutane and propane), was widespread.Butane, carbon disulfide, carbon dioxide, carbon tetrachloride,dichlorethylene, ethane, ethylamine, ethyl bromide, gasoline,methyl bromide, methyl formate, methylene chloride, methyla-mine, methyl chloride, naphtha, nitrous oxide, trichloroethylene,and trimethylamine were also used during this time period(Nagengast, 1988; Bodinus, 1999; Calm, 2012). Carbon dioxidesaw widespread application for cargo refrigeration on ships from1890 until about 1930, with continued use on British ships until1940 (Bodinus, 1999). Carbon dioxide was also used in brew-eries, packing plants, and other large cold storage applications aswell as smaller cold storage and display counters in public spacessuch as food markets, hotels, and hospitals, where it was pro-moted as a safer alternative to sulfur dioxide and ammonia(Bodinus, 1999). At the 1904 St. Louis World’s Fair,Brunswick Refrigeration company introduced the first self-contained mechanical refrigerator using ammonia and cooledwith water; in 1914 Fred Wolf Company marketed the first air-cooled, electric, self-contained refrigerator; and in 1916 AlfredMellowes introduced an improved refrigerator design thatGeneral Motors bought in 1918 and produced under itsFrigidaire brand. By 1923, Kelvinator, first with automatic tem-perature control, had 80% of the market. In 1927 GeneralElectric introduced the first mass-produced completely sealedsystem with separate temperature control for frozen and refri-gerated food and quickly dominated the market, while Electroluxmarketed the gas-fired absorption refrigerator (using ammonia)for homes not yet electrified (Nagengast, 1988, 1997; NAE,2013). Refrigerators in the 1920s and early 1930s used a varietyof refrigerants, including ethyl chloride (Allison, Holmes),

sulfur dioxide (General Electric, Westinghouse), and methylchloride (Williams) (Nagengast 1997).

Air conditioning was introduced in the first hospital in 1906(Boston Floating Hospital), in the first hotel (Congress HotelChicago), and in numerous other public and private buildings. In1928 Carrier introduced the “Weathermaker” home air condi-tioner, and in 1929, Frigidaire marketed the first room A/C usingsulfur dioxide as the refrigerant (NAE, 2013).

This transition to mechanical ice making was driven by acombination of convenience, concern about the health risks ofice made from polluted water, and the unreliability of ice due tohot weather events and delivery interruptions. Harvested andmanufactured ice successfully competed with mechanical refrig-eration in commercial and residential applications until the1930s and 1940s, when CFCs made the operation of smallmechanical refrigerators safe. The remaining uses of ice forrefrigeration are in remote locations lacking electrification andin specialized applications where ice has a technical advantage,such as in keeping fish both refrigerated and humid.

Mechanical refrigeration was considered more convenientthan ice, which could not consistently provide safe temperaturesfor food refrigeration, and required more frequent delivery in hotweather. However, mechanical refrigeration had serious safetydrawbacks. In many locations the electric power supply wasunreliable and leaks of the most common refrigerants—sulfurdioxide and ammonia—typically required rapid evacuation ofhomes and buildings. People who came into contact with toxicrefrigerants suffered from vomiting, burning eyes, and painfulbreathing. Accidents with sulfur dioxide and ammonia rarelyresulted in death, but accidents with methyl chloride refrigerantwere frequently fatal.

Commercial and residential customers were well informed ofthe known trade-offs of ice versus mechanical refrigeration. Icerefrigeration suppliers promoted the simplicity and reliability ofice and warned against the hazards of poisonous and flammablerefrigerants. Mechanical refrigeration suppliers, on the otherhand, cautioned customers about the possibility of contaminatedice and pointed to the inconvenience and lack of reliabilityassociated with ice refrigeration.

Although this flammability versus toxicity risk trade-off dis-cussion was highly informed, not enough was known at that timeabout the chronic toxicity effect of repeated exposures to toxicrefrigerant leaks over a long period of time. Minor use of methylbromide and carbon tetrachloride, highly toxic ozone-depletingsubstances, continued in the first half of the 20th century.However, the portion of carbon tetrachloride used as a refrigerantwas minor in comparison to that used as a solvent, fire extin-guishing agent, and chemical feedstock. The quantity of methylbromide used as a refrigerant was also minor compared with thequantities used as pesticides, fire extinguishing agents, andanesthetics. All together, the release of all ODSs used before1930 posed little to no risk to the ozone layer at that time.Similarly, because these substances have a relatively short atmo-spheric lifetime, their pre-1930 use did not contribute in a mean-ingful way to the serious ozone depletion experienced in the1970s and later. Table 4 summarizes flammable and toxic refrig-erants in use before CFCs were introduced.


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

1930 to 1990: CFCs and HCFCs replace most toxicand flammable refrigerants

In late 1928, executives from General Motors (GM) and itsrefrigerator manufacturing division, Frigidaire, assignedThomas Midgley and a small team of engineers at the GMResearch Laboratory the task of inventing a nontoxic, nonflam-mable, and noncorrosive refrigerant. Midgley determined thatelements with boiling points appropriate for refrigeration wereclustered on the Langmuir periodic table, which is arrangedaccording to the number of vacancies in the outer shell ofelectrons. Working with Albert Henne and Robert McNary,Midgley ruled out unstable and inert elements. This left forconsideration carbon, nitrogen, oxygen, sulfur, hydrogen, andthe halogens fluorine, chlorine, and bromine. Others had dis-missed fluorine because chemical substances containing fluorineare often toxic and/or corrosive (Kauffman, 1989).

Midgley and Henne, however, were familiar with Belgianchemist Frédéric Swarts’s theory that the toxicity of fluorinecould be negated if it were strongly bonded with chemicals thathad complementary valences (Andersen and Sarma, 2002).Within two or three days of receiving their research assignment,they had identified chlorofluorocarbons (CFCs) as prime can-didates and synthesized dichloromonofluoromethane (CFC 21)from carbon tetrafluoride. Within months, Midgley and histeam satisfied the existing criteria for confirmed that CFCswere nonflammable, nonexplosive, noncorrosive, very low intoxicity, and odorless, and that their vapor pressures and heatsof vaporization made them suitable for refrigerationapplications.

Within a year, GM patented the family of CFCs and perfectedthe manufacturing process for the first commercial substances

trichlorofluoromethane (CFC-11) and dichlorodifluoromethane(CFC-12). The Midgley research notes also identified otherrefrigerants, such as HFC-134a (1,1,1,2-tetrafluoroethane), thatwere unappreciated at the time because the stratospheric ozonedepletion and climate forcing were not yet identified (Andersenand Sarma, 2002). On 27 August 1930, GM and DuPont formeda joint stock company, the Kinetic Chemical Company, to man-ufacture and market CFCs (Andersen and Sarma, 2002).

In the 1930s air conditioning gradually became more com-mon as companies produced systems large enough to cool occu-pied spaces using large CFC refrigerant charges that would beprohibitively dangerous if toxic and flammable. In 1947 engi-neer Henry Galson perfected a low-cost residential air condi-tioner design that was manufactured under license by a numberof manufacturers (National Academy of Engineering, 2013). By1970, more than half of U.S. cars and most new homes hadcentral air conditioning, with window A/C affordable forhomes without ductwork.

CFCs andHCFCs rapidly replaced other refrigerants in all butapplications where companies accepted the increased risk offlammable and toxic refrigerant releases or in applicationswhere the existing technologies were more energy efficient.For example, ammonia continued to be used in cold storage,ice making, ice rinks, and absorption refrigerators using gasflame as an energy source. Hydrocarbons continued to be usedin industrial refrigeration, particularly at oil and chemical facil-ities (Andersen and Sarma, 2002).

CFC-12 soon became the dominant refrigerant in most smallappliances, refrigerated storage applications, and many othernew applications. CFC-11 became dominant in A/C applicationsuntil the 1950s, when HCFC-22 was applied in commercialrefrigeration, room A/C, and building A/C. From the 1940s

Table 4. Flammable and toxic refrigerants in use before CFCs (Andersen and Sarma, 2002)

Refrigerant Flammability Toxicity Comment

Ammonia Mildly High but noxiousproperties promotesafety

Predominant in industrial and heavy commercial refrigeration;strong odor warns of leaks but even small leaks cause an odor;competitive in A/C; some light commercial and householdrefrigerators (particularly models using the absorption cycle)

Carbon dioxide Extinguishesfire

Low Competitive in early A/C; high pressure requires sturdyconstruction

Dimethyl ether High Moderate One of the first widely used refrigerantsEthyl chloride None High Some light commercial and household refrigeratorsMethyl chloride None High Distant second preference for light commercial and household;

competitive in A/C; competitive in industrial and commercialrefrigeration

Isobutane High Low Some light commercial and household refrigeratorsSulfur dioxide None High, but noxious

properties promotesafety

Preferred for household refrigerators; strong odor warns of leaksbut even small leaks spoil food; competitive in industrial andcommercial refrigeration and A/C

Methyl bromide Extinguishesfire

High Infrequent use as refrigerant

Carbon tetrachloride Extinguishesfire

High Infrequent use as refrigerant


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

onward to the 1990s, CFCs and HCFCs were also marketed asaerosol propellants, solvents, foam blowing agents, and more.

1975 to 1980: CFC aerosol propellant boycotts, bans,and voluntary agreements

Until early 1974, CFCs and HCFCs were considered perfectin every known way because neither stratospheric ozone deple-tion nor climate alteration was well understood or anticipated.Refrigeration and air-conditioning equipment manufacturers andtheir customers came to think of CFCs and HCFCs as “wondergases.” Because these were relatively inexpensive, near-absolutecontainment was not a design priority for equipment manufac-turers or users. Refrigerants were typically vented at service toavoid any risk of damage to equipment from refrigerants thatmight be contaminated with air, acids, water, or metal filings.Energy efficiency of refrigerators and air conditioning wasmostly unmeasured and unregulated and considered by manu-facturers to be unimportant to sales, and therefore not worth theextra engineering and manufacturing costs to achieve.

Following the call to action resulting from the findings ofMolina, Rowland, Crutzen, and others in the early 1970s, hydro-carbons became substitute propellants for cosmetic and conve-nience aerosol products. Not-in-kind alternatives for aerosolhairspray include pumps, sprays, and creams; deodorant alter-natives include pumps, sprays, sticks, and roll-ons. Once indus-try made the transition to hydrocarbon aerosol products,the consumer cost was far less than when CFCs were used, andthe lower cost of hydrocarbon aerosol propellants increased theprofits to cosmetic product manufacturers.

By 1975, consumer boycotts of CFC hairspray and deodorantwere penetrating the American market and influencing sales inCanada, Europe, and Japan. In June 1975, S.C. JohnsonCompany announced that it would phase out CFCs as aerosolproduct propellants. One month later the Sherwin-WilliamsCompany, Bristol Meyers, and Mennen joined S.C. Johnson inaggressively advertising alternatives, including pumps, sprays,creams, and sticks. In 1978, the United States banned the use ofCFC propellants in products considered nonessential, whichaccounted for more than 80% of all U.S. CFC aerosol products.

[By 1978] Canada had achieved a 50 per centdecrease in aerosol production by voluntary agree-ment with industry, and had announced its intentionto issue regulations in 1979. Sweden banned themanufacture and import of aerosol products contain-ing CFC aerosol propellants, effective 1 July 1979.The Netherlands issued regulations that required awarning label on all aerosol products containingfluorocarbons sold after 1 April 1979 and furtherprovided that a ban would be imposed on non-essential aerosol use if similar action were taken bythe main producing nations. Germany was pursuinga cooperative approach with industry directed atreducing use of fluorocarbons in aerosols by 30 percent by 1979. Norway recognized the gravity of therisks despite uncertainties, and called for interna-tional action. In March 1980, the Council of the

European Economic Community legislated a 30per cent cutback in CFC aerosol use from 1976levels. (Andersen and Sarma, 2002, p. 51)

The European Commission (EC) reduction was enacted underDecision 80/372/EEC, in March 1980.

Hydrocarbon aerosol products have flammability risks notexperienced with CFC aerosol products, and there was at leastone costly commercial fire before warehouse and transportationfire codes were modified to account for the additional flammableingredients in hydrocarbon aerosol products (IndustrialHydrocarbons, Inc. [IH], 2012). In the first 10 years after theCFC aerosol product ban (1978–1987) there was an average of3,922 accidents per year reported to the Consumer ProductSafety Commission (CPSC), which amounted to one incidentper 606,000 cans sold. In the last 10 years (2001–2010), theaverage has been 4,388 per year, which amounted to an averageof one incident per 832,000 cans sold (IH, 2012).

1990 to 2015: HFCs replace most CFC and HCFCrefrigerants, with flammable and toxic “naturalrefrigerants” making a slow comeback

When the Montreal Protocol was instituted in 1987, there wasno time to wait for new technology, despite the success of thehead start on phase-out of aerosol products by some countries.Sales of ODSs were increasing rapidly and stratospheric ozonedepletion was recognized. ODS replacements had to be foundimmediately. Hydrocarbon refrigerants were quickly proposed toreplace CFCs, but the typical leak rates and service ventingpractices would have been unsafe in many applications, particu-larly in equipment with large refrigerant charges. Additionally,no one was confident of how quickly containment, detection,and isolation technology could be implemented to mitigateflammability.

As soon as the Montreal Protocol was signed, in 1987, thefluorocarbon chemical industry and its refrigerant customersmoved rapidly to market existing HCFC-22 and HCFC-142b toreplace CFCs, to commercialize HFC-134a to replace CFC-12,and to commercialize HCFC-123 to replace CFC-11. HFC-134aand HCFC-123 had been identified decades earlier and patentedin the 1970s (Andersen and Sarma 2002). New chemicals—including HCFC-225, HFC-143a, and HFC-124—were inventedto replace ODSs in applications other than refrigeration. By thetime Gustav Lorentzen and colleagues filed for their first mod-ern patent for carbon dioxide refrigeration systems in 1989(granted in 1993), this technology was too late to capture anyof the market for the CFC phase-out, although it is currentlyreplacing HFCs in many stationary applications (Lorentzen andPettersen, 1993).

To speed commercialization of new fluorocarbon refriger-ants, industry formed the Programme for AlternativeFluorocarbon Toxicity Testing (PAFT) in 1988 and theAlternative Fluorocarbon Environmental Acceptability Study(AFEAS) in 1989 with the strategy of robust cooperative finan-cing of research into toxicity and environment impacts by themost respected laboratories and other research institutes.


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

Advocates of nonfluorocarbon refrigerants organized aroundthe concept of “natural refrigerants,” defined as naturally occur-ring and existing in nature, but modified their list of candidatesto rule out many of the naturally occurring toxic and flammablerefrigerants used before the invention of CFCs. Now naturalrefrigerants usually include only ammonia (R-717), hydrocar-bons (isobutane [R-600a] and pentane [R-290]), carbon dioxide(R-744), and sometimes water (R-718) and air (R-729).

Natural refrigerants staged a comeback in the 1990s thatcontinues to gain market share. In 1992, Greenpeace inspiredEuropean government, industry, and consumer support for theuse of hydrocarbons in domestic refrigerators. Within one year, ahydrocarbon-based domestic refrigerator was introduced inGermany, and soon hydrocarbon refrigerators gained marketdominance in Europe and penetrated markets in Asia, includingJapan, but, so far, not the United States. Meanwhile, suppliers ofequipment using ammonia as a natural refrigerant recapturedmarket share in HCFC cold storage and food freezing subsectors.They also made limited progress in applying ammonia to com-mercial refrigeration and A/C using secondary loops for safety.At the same time, European researchers with the support ofEuropean vehicle manufacturers, particularly the German auto-mobile manufacturers, pursued carbon dioxide for use in mobileair conditioners (Andersen and Zaelke, 2003). Later in thispaper, the transitions in mobile air conditioners are introduced.

In the majority of cases, the replacement of ODSs was accom-plished with no compromise in any measure of environmentalrisk, and manufacture of equipment and safety performance aremaintained or improved. Not-in-kind alternatives replacingabout 85% of ODS use and emissions were benign, such as theelimination of testing, training, and accidental discharge of halonfire extinguishing agents or the elimination of CFCs solventswith no-clean soldering and metal forming. HFC metered-doseinhalers (MDIs) used in treatment of asthma and chronicobstructive pulmonary disease (COPD) more accurately dis-pense the medicine than the CFC products they replace, andsterilization without CFCs is superior in every way (Andersenand Sarma, 2002).

The HFCs that replaced CFCs had generally lower GWP andequal or higher energy efficiency. For example, HFC-134a (1430times as potent as CO2) has replaced CFC-12 (GWP ¼ 10,900)in many refrigeration and A/C applications while achieving up to30% improvement in energy efficiency and 30% reduction inrefrigerant leak rates. But the introduction of new technology isnot without its challenges. In some cases the new technology hashigher or new risk, primarily in manufacturing and servicing,such as the higher risk of worker exposure to ammonia refriger-ant or the fire risk in servicing equipment charged with butaneand pentane hydrocarbon refrigerants. In still other cases, thenew technology may be environmentally superior to the one itreplaced, yet arguably still not acceptable under increasinglystringent environmental standards. Thus, high-GWP HFCs arenow proposed for phase-down under the Montreal Protocolbecause of unanticipated emissions in developing countries andbecause environmentally superior low-GWP alternatives arenow available. As a further example, some low-GWP HFCrefrigerants whose atmospheric degradation by-products maybe unsustainable over the long run may need further review

(McCulloch, 1999; Luecken et al., 2010; Henne et al., 2012).Atmospheric degradation of some HFCs produces trifluoroace-tic acid (TFA; CF3COOH) via hydrolysis of trifluoroacetyl fluor-ide (CF3COF). TFA is a mildly phytotoxic (Boutonnet et al.,1999) strong organic acid (Henne and Fox, 1951) with no knowndegradation mechanism in water. However, risk assessmentsindicate that deposition of TFA from current emissions ofHFCs does not pose a risk to aquatic ecosystems, and technologyis available to reduce emissions to near-zero levels (Lueckenet al., 2010; Metz et al., 2005).

Support by industry leaders hastened the transition from CFCto HFC refrigerants. The mobile air conditioning (mobile A/C)sector was first, in 1988, to agree to recover and recycle refrig-erant and was the first in 1990 to announce plans to replace CFC-12 with HFC-134a. At that time, mobile A/C accounted for up tohalf of all nonaerosol CFC sales and emissions. The early mobileA/C commitment to HFC-134a gave chemical manufacturers theconfidence to invest in full-scale production, even before toxi-city testing and government approval was completed (Andersenand Morehouse, 1997). HFC-134a was quickly embraced byother refrigeration and A/C applications because it was similarto CFC-12, nonflammable, nontoxic, proven compatible withspecific lubricants, competitively priced, and widely available.Coca-Cola, the world’s largest customer for refrigerator casesand vending machines, also made an early worldwide commit-ment to HFC-134a, which encouraged its suppliers in bothdeveloped and developing countries to take ozone layer protec-tion seriously and to move quickly with the CFC-12 phase-out(Andersen and Sarma, 2002). NowCoca-Cola is fully committedto CO2 for vending machines, refrigerated display cases, anddrink dispensers and will phase out HFC-134a in new equipmentpurchases.

As of the end of 2009, the parties to the Montreal Protocolhad phased out the consumption of 98% of all of the chemicalscontrolled by the Protocol. In addition to providing criticalozone layer protection, the agreement also produced substan-tial climate protection benefits. Because ozone depleting sub-stances are also global warming gases, the reduction in ozonedepleting substances between 1990, when they reached peaklevels, and the year 2000 has yielded a net integrated reductionof approximately 25 billion tonnes of CO2-equivalent globalwarming gases. This figure does not include the additional CO2

emissions that were avoided due to improvements in the energyefficiency of refrigeration and A/C systems when the globalCFC phaseout ushered in a new generation of equipment. Asrefrigeration and A/C manufacturers retooled their products toaccommodate new ozone safe refrigerants, many also took theopportunity to make improvements in overall operating effi-ciency. At this time, many national governments were begin-ning to adopt efficiency standards and incentive programs andcustomers were becoming increasingly concerned about appli-ance electricity cost.

The U.S. Environmental Protection Agency (EPA) estimatedthe gains to customers and society of the replacement of old air-conditioning equipment when 44% of existing chillers were con-verted or displaced by non-CFC chillers. (Chillers in large build-ings exhibited energy efficiency improvements of up 40% overolder models.) Thus, U.S. EPA estimated that building owners


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

who install new chillers saved almost $500 million and 7 billionkilowatt hours of electricity in 1999, representing the annualelectrical needs of 740,000 U.S. households. These savingsavoid emissions of more than 4 million tons of carbon dioxideand 34,000 tons of sulfur dioxide (SO2). The reduction in SO2

represents the annual emissions of one and one-half large coal-fired power plants. Similarly, projects involving CFC chillerreplacement in India resulted in 30% improvement in energyefficiency with average savings for each chiller replaced of214,000 kWh/yr or ~$12,000/yr (also CO2 equivalent bene-fits—0.82 kg CO2 equivalent /kWh) and a reduction of loadcapacity of ~130 kW/chiller.

2010 and continuing: Natural refrigerants andlow-GWP HFCs compete on the basis of life-cycleclimate performance (LCCP)

Policymakers, public interest organizations, and companiesworked hard to select alternatives and substitutes to CFCs withthe lowest possible environmental impact. It was widely recog-nized that the climate impact of any refrigeration or A/C tech-nology should be comprehensively accounted over the lifetimeof the product, taking into account the direct emissions of green-house gas refrigerants, the indirect emissions of energy used topower the technology, and the embodied emissions from themanufacture, distribution, and disposal of the technology atend of product life.

The concept of TEWI is used to calculate carbon equivalentlife-cycle greenhouse gas emissions (U.S. Department of Energy[DOE], 1991): TEWI ¼ life-cycle direct chemical greenhousegas emissions þ lifecycle indirect CO2 energy emissions(Fischer et al., 1991). Because TEWI neglects emissions asso-ciated with product manufacturing, including HFC-23 bypro-duct greenhouse gas emissions during HCFC-22 refrigerantmanufacturing, it was extended in 1997 as life cycle warmingimpact (LCWI): LCWI¼ TEWI (direct and indirect)þ chemicalproduction þ atmospheric breakdown products þ transport(Papasavva and Moomaw, 1998).

In 1999 LCWI was expanded into “life-cycle climate perfor-mance” (LCCP): LCCP ¼ LCWI (direct þ indirect þ chemicalproduction þ atmospheric breakdown products þ transport) þcomponent manufacturing (Andersen, 1999).

Finally, in 2003–2006, scientists who developed LCWI andLCCP, through global consensus, developed an LCCP model formotor vehicle A/C called “GREEN-MAC-LCCP,” which is anSAE International (previously called the Society of AutomotiveEngineers, SAE) standard and hosted on the U.S. EPA website(Hill and Papasavva, 2005; Papasavva et al., 2008; Papasavvaet al., 2010; Papasavva and Andersen, 2011).

Today, natural refrigerants compete favorably with fluorocar-bon refrigerants in an increasing variety of applications andsystems. Hydrocarbon natural refrigerants are competitive insystems with relatively small charges, but only in a very smallnumber of systems with large charges. Ammonia is increasinglycompetitive in industrial and commercial refrigeration, but hasnot penetrated A/C applications. In Japan, there is considerablesuccess with carbon dioxide heat-pump water heaters in markets

where the only water heating competition is electric resistanceheating (Metz et al., 2005).

The carbon footprint for refrigerant emissions depends on theGWP of the refrigerant and the emissions during manufacture,use, service, and at the end of product lifetime. The carbonfootprint for electric refrigeration and A/C equipment dependson electric generation fuel source, efficiency in power generation,distribution processes, and electricity transmission losses.

Refrigerant GHG emissions for electrically powered refrig-eration and A/C can be up to about 95% of the carbon footprintfor equipment powered entirely by sources like hydroelectric, butare more commonly 10 to 30% for equipment powered by atypical mix of coal, oil, or biomass. The portion of refrigerantcarbon footprint is lower in climates with long hot and humidcooling seasons.

The carbon footprint for motor vehicle A/C using fossil fuelsdepends on the fuel efficiency of the engine, the emission rate ofthe refrigerant, and the total hours of A/C operation. In climateswith little cooling or dehumidifying, the refrigeration emissionsdominate the carbon footprint, while in climates with long cool-ing and dehumidifying seasons the energy consumption dom-inates. In the United States, mobile A/C refrigerant emissions areabout one-third of A/C fuel emissions, while in climates likeEurope with less air conditioner use the refrigerants are abouthalf of the A/C carbon footprint.

Each refrigerant has a potential energy efficiency thatdepends on its chemical and physical properties and a realizedenergy efficiency that depends on factors including design,component efficiency, and system controls. Design featuressuch as a secondary cooling loop requiring an additional heatexchanger and long cooling lines, necessary for safe use of toxicand flammable refrigerants, have an energy penalty.

The Montreal Protocol TEAP reports that systems using low-GWP alternatives achieve equal or superior energy efficiency ina number of sectors, including domestic refrigeration, commer-cial refrigeration, and some types of air-conditioning systems.For example, hydrocarbon and ammonia systems are typically10–30% more energy-efficient than conventional high-GWPHFC systems. Sectors achieving superior energy efficiencywith low-GWP refrigerants include mobile A/C, small roomair-conditioning, and small and large reciprocating, scroll, andscrew chillers (UNEP, 2009).

Schwarz et al. (2011) identified technically feasible and cost-effective low-GWP alternative technologies capable of achievingequal or better energy efficiency in 26 refrigeration and A/Csubsectors. About half of the technology identified as superiorwas capable of achieving 30% higher energy efficiency than thehigh-GWP equipment it replaced.

Additional improvements in overall system energy efficiencyare likely to occur as HFCs are gradually replaced or contained.As A/C and refrigeration manufacturers retool their products toaccommodate a new refrigerant, they will redesign them toimprove efficiency, as witnessed during the CFC phase out.The extent to which additional improvements are made willdepend on consumer demand, cost, safety, policy incentives ordisincentives, and other drivers.

McNeil et al. (2008) identified a cost-effective opportunity toavoid 304 Mt CO2 by 2030 in residential refrigeration and 214


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

Mt CO2 in commercial space cooling. IEA (2012) suggests thatimproving energy efficiency could give theworld another 5 yearsto change course and begin the transition to renewables and otherlow-carbon energies.

Unresolved are questions of regarding adverse health effectsof air conditioning. At issue is whether air conditioning itself ishealthy, how to avoid “sick building” symptoms (headache,fatigue, and sensory irritation) most often attributed to indoorair quality, and how to avoid more serious illness, such asLegionnaire’s disease, caused by bacterial contamination propa-gated and dispersed by air conditioning (Wheeler, 1999).

Case Study of the Transition from CFC-12to HFC-134a with Lessons for the ongoingTransition to HFO-1234yf

This portion of the critical review examines in depth 25 years ofextraordinary cooperation exhibited between automobilemanufac-turers, automobile air conditioner service organizations, govern-mental environmental authorities, and environmental nongovern-mental organizations (NGOs) to reduce refrigerant emissions

throughmanufacturing practices, containment, recovery, recycling,and destruction at the end of vehicle life and the complementarycooperative efforts to continuously improve the environmentalperformance of vehicle A/C in both direct refrigerant emissionsand energy efficiency (Atkinson, 2008). A timeline for the use ofrefrigerants in mobile air conditioning is given in Table 6.

The first mechanical motor vehicle air conditioners

For a long time, opening windows, including “wind wing”side windows and hinged or roll-up windshields, provided theonly automobile ventilation. Some automobiles were vented bypicking up air from the base of the windshield or on the side ofthe car, and in locations with low humidity, evaporative coolershung from a side window offered some relief. However, it wasnot until the 1960s that rear vents were added to create “flow-through” ventilation with the windows closed (Hoffpauir, 2012).Fresh air heaters were introduced in the 1940s that also used theblower to increase ventilator airflow.

In 1930 the Kelvinator Company customized a Cadillac withan air conditioner hung like a trunk above the rear bumper andpowered by a separate gas engine, in 1933 Popular Sciencefeatured floor-mounted AC from an unspecified manufacturer,

Table 5. Mobile A/C timeline

1883 Karl Benz founds Benz and Cie and builds the first automobile1884 W. Whiteley demonstrates the first vehicle A/C for horse-drawn carriages using a wheel-driven fan to

blow air across ice1928 CFCs invented at General Motors Research Laboratory by Thomas Midgley, Albert Henne, and Robert McNary1939 Packard produces the first vehicle with CFC A/C in the 1940 model1974 Molina and Rowland publish hypothesis that CFCs are destroying the ozone layer that protects life on earth from

harmful ultraviolet radiation1977 Harrison Radiator and Allied Chemicals conducted a joint evaluation of HFC-134a for automotive air conditioning.

In 1978 Harrison Radiator conducted wind tunnel tests on a Chevrolet.1985 Vienna Convention for the Protection of the Ozone Layer1987 Montreal Protocol on Substances that Deplete the Ozone Layer1988 TheMobile Air Conditioning SocietyWorldwide (MACS) and theMotor VehicleManufacturers Association (MVMA)

form an ad hoc committee to pursueCFC-12 recycling chaired by SimonOulouhojian (MACS, U.S. E.P.A.,) and BobBishop (soon replaced by James Baker) (General Motors) and coordinated by Stephen O. Andersen (U.S. EPA)

1989 CFC recycling commercialized with SAE standard, UL performance testing, automobile manufacturers agreement toallow under warranty repair and with endorsement of NGO and government authorities; Friends of the Earth callsfor a national ban on the sale of small cans of CFC-12 refrigerant that can be used by do-it-yourself (DIY) carowners to recharge leaking systems on a continuous basis; and Nissan pledges to be CFC-free by 1993, includingrefrigerants, solvents, and foam blowing agents used in seats, steering wheels and bumpers;

Gustaf Lorentzen files for a patent on an improved carbon dioxide refrigerant system1990 Mercedes, Chevrolet, and Volvo are first to introduce vehicles with CFC-free A/C; U.S. Internal Revenue Service

confirms that recycled refrigerants are not subject to CFC floor tax; the U.S. Clean Air Act of 1990 requires thattechnicians be trained and certified to standards as least as stringent as specified in SAE J-1989 under certificationprograms of the National Institute for Automotive Service Excellence (ASE) or the Mobile Air ConditioningSociety (MACS) and that recycling equipment satisfying SAE and UL standards be used on any repair of vehicleA/C

1991 Recycling mandatory in Connecticut, Hawaii, Oregon, and Vermont; recycling equipment mandatory in Ford, GM,and Volvo dealerships

1992 United Nations Framework Convention on Climate Change (UNFCCC) signed by countries at the Rio Earth Summit1993 Gustav Lorentzen granted patent for improved carbon dioxide refrigerant system1994 Global production of vehicles almost CFC-free (with exceptions of some developing countries)

(Continued )


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

Table 5. (Cont.)

1994–1997 European Union sponsors RACE (Refrigeration and Automotive Climate under Environmental Aspects) industryconsortium to develop and demonstrate CO2 vehicle A/C

1996 Shared Mercedes/BMW patent for CO2 heat pump1997 Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC) signed in Japan1998 First “Phoenix Forum” on alternatives to HFC A/C with discussion of CO2, and HFC-152a1999 Second “Phoenix Forum” on alternatives to HFC-134a A/C

Phoenix Forum decides by consensus to create the “Mobile Air Conditioning Climate Protection Partnership” andappoints Stephen O. Andersen (U.S. EPA), Ward Atkinson (SAE),) and Simon Oulouhojian (Mobile AirConditioning Society Worldwide) as Co-Chairs

2000 Third “Phoenix Forum” on alternatives to HFC-134a A/C2001 SAE creates new project on benchmarking HFC-134a vehicle A/C for energy efficiency and emissions and testing of

alternatives under its Cooperative Research Program (CRP)U.S. EPA and Environment Canada become first financial contributors to SAE CRP for vehicle A/C

2002 Fourth “Phoenix Forum” on energy efficient alternatives to HFC-134a A/CChina stops production of vehicles with CFC A/C (31 December 2002)First VDA Alternative Refrigerant Winter Meeting, Saalfelden, AustriaToyota’s fuel cell hybrid vehicle (FCHV) includes the world’s first commercially produced vehicle with CO2 air

conditioner—a Denso electrically driven, hermetically sealed, air conditioner/heat pump using natural CO2

refrigerant2003 India stops production of vehicles with CFC A/C (December 31, 2003)

Fifth “Phoenix Forum” on energy efficient alternatives to HFC-134a A/C Second VDA Alternative RefrigerantWinter Meeting, Saalfelden, Austria

2004 Sixth “Phoenix Forum” on energy efficient alternatives to HFC-134a A/C Third VDAAlternative Refrigerant WinterMeeting, Saalfelden, Austria; SAE International launched the Improved Mobile Air Conditioner CooperativeResearch Program I-MACCRP, with a three-year budget of over $5million dollars to reduce refrigerant leakage byat least 50% and to increase A/C system energy efficiency by at least 30%.

2005 Fourth VDA Alternative Refrigerant Winter Meeting, Saalfelden, Austria2006 Seventh “Phoenix Forum” on energy efficient alternatives to HFC-134a A/C

EC, United States and Japan environmental authorities agree to work cooperatively and swiftly to remove globalbarriers to the adoption of refrigerants to replace HFC-134a; U.S. EPA’s Kristen N. Taddonio is appointed to leadthe U.S. effort

Fifth VDA Alternative Refrigerant Winter Meeting, Saalfelden, AustriaOnMay 17, the EC passed the mobile A/C F-gas directive (Directive 2006/40/EC of the European Parliament and the

Council) requiring that air conditioners sold on new “type” vehicles in the EU after 2010 and all vehicles sold inthe EU after 2017 use refrigerants with GWP<150. At the time of the announcement, the only publically disclosedrefrigerants satisfying this criterion were hydrocarbons (GWP ~5), CO2 (GWP¼ 1), and HFC-152a (GWP ~124).

Within weeks of the EC F-Gas Directive more than five international chemical manufacturers, including Asahi,Arkema, DuPont, Honeywell, Ineos, and Sinochem, announced refrigerants suitable for motor vehicle A/C withGWP < 150).

2007 Eighth “Phoenix Forum” on energy-efficient alternatives to HFC A/CSixth VDA Alternative Refrigerant Winter Meeting, Saalfelden, Austria

2008 Ninth “Phoenix Forum” on energy efficient alternatives to HFC-134a A/C Seventh VDA Alternative RefrigerantWinter Meeting, Saalfelden, Austria

At a December 9, 2008, meeting of automobile manufactures, mobile A/C system and component suppliers, mobileA/C service associations, environmental authorities, and public interest organizations, all but four of more than 70participants agreed that HFO-1234yf is the refrigerant-of-choice to replace HFC-134a in motor vehicle A/C.

MACCPP chairs put forward an elaborate plan for commercialization of HFO-1234yf at the February 4meeting of theMobile Air Conditioning Society Worldwide, including standards development by SAE, agreement on safetystandards to replace outright U.S. state and other barriers to flammable refrigerants, and cooperation to speedU.S. EPA SNAP and EC REACH approval (Registration, Evaluation, Authorisation and Restriction of Chemicalsubstances).

Eighth VDA Alternative Refrigerant Winter Meeting, 11–12 February, Saalfelden, Austria.Japan SAE Meeting 4–5 March, Tokyo Japan, confirms the choice of HFO-1234yf and organizes working groups to

rapidly implement necessary technical standards.SAE Meeting 14–16 July, Scottsdale, AZVehicle Thermal Management Systems Conference & Exhibition, Phoenix, AZ

(Continued )


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

in 1934 Houde Engineering and Carrier demonstrated the firstself-contained automobile conditioner, and 1935 A/C systemsdesigned by McCord Radiator & Manufacturing were tested onbuses (Bhatti, 1999; Anonymous, 1933). In 1937 the KelvinatorCompany installed air conditioning on a White Research Coach.GM engineers developed a prototype trunk-mounted car A/C

1939 (Bhatti, 1999). The first factory-installed mechanicalmotor vehicle A/C was offered on the 1940 model yearPackard and the second system was on a 1941 Cadillac (TheOnline Imperial Club, 2001). Chrysler DeSoto offered factory-installed A/C in 1942 (Hoffpauir, 2012). Air conditioning wassuspended during World War II and was not revived in volume

Table 5. (Cont.)

2010 Ninth “Phoenix Forum” on energy-efficient alternatives to HFC-134a A/C Ninth VDA Alternative RefrigerantWinter Meeting, Saalfelden, Austria. In July, General Motors announced that it would adopt HFO-1234yf on itsU.S. models from 2013

2011 Tenth “Phoenix Forum” on energy efficient alternatives to HFC-134a A/C2012 Informally in February and officially inMay, the EC suspended enforcement of the mobile A/C F-gas Directive due to

shortages in supply of HFO-1234yf as a consequence of the earthquake and tsunami in Japan that destroyed theAsahi chemical manufacturing plant that was supplying refrigerant to DuPont and Honeywell under contract. InSeptember, Daimler issued a press release saying that HFO-1234yf is unsafe and that it intended to revert to HFC-134a in violation of the F-gas Directive. In December, the EC rejects Daimlers claim and warns that the F-GasDirective will be strictly enforced. In December 2012, SAE reaffirmed that HFO-1234yf “is a safe and acceptablealternative refrigerant for mobile air conditioning systems that can be used to meet new environmental andconsumer needs” and reported that “the majority of the OEMs involved in the new CRP do not believe that any ofthe new information reviewed will lead to a change in the overall risk assessment.”

2013 Only Daimler still claiming that their engineers are unable to safely use HFO-1234yf in automobile A/C; Audi, BMW,Daimler, and Volkswagen announce plans to form a consortium to re-start development of a CO2 automotive airconditioning system and request a delay in enforcement of the EC F-gas Directive.

Table 6. U.S. market penetration of factory-installed vehicle A/C (Bhatti, 1999)

Year(s) Companies Notes

1930s Kelvinator, Houde, Carrier, McCord Prototypes Only1940–1942 Packard, Cadillac <3000 at �$3001942–1945 Few during WWII Unavailable1946–1952 Luxury cars and aftermarket1953–1954 Factory-installed on Buick, Cadillac, Chrysler,

Oldsmobile, Packard and Nash; Nash is first front-end,integrated heating, ventilating, and air-conditioningsystem

�29,000 at $600 in 1953; 36,000 at �$400 to $600;<0.5% of sales

1955 Factory-installed on Buick, Cadillac, Chevrolet, Chrysler,DeSoto, Dodge, Ford, Hudson, Lincoln, Mercury,Nash, Oldsmobile, Packard, Plymouth, and Rambler

118,000 �1.5% of sales

1956 Every American Auto Company offers factory-installedAC

228,000 �3% of sales

1957–1959 1957 Cadillac Eldorado Brougham is first car with ACStandard; 1958 Nash Rambler cost $2000 includingA/C

�4% of sales in 1957; �5% of sales in 1958;Cars sold with factory A/C exceeds 1 million

1960s Factory-installed AC on 50–90% of luxury cars; A/Coffered for as little as $250 on economy cars and up to$650 on luxury cars; after-market A/C for as little as$200.

�8% of sales in 1961;�11% of sales in 1962;�14%of sales in 1963;�40% of sales in 1967;�55% ofsales in 1969

1970s Added resale w/AC greater than the added AC cost fornew cars

1980s Montreal Protocol Signed 1987 �70% of sales in 19801990s Standard equipment on about half the cars sold �94% of sales in 19902013 >99% of car sales


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

until 1953, when Chrysler, GM, and Packard offered systems onluxury models with components under the hood and in the trunk;Chrysler used HCFC-22 and GM and Packard used CFC-12. In1954, GM developed the A/C self-contained system still usedtoday with evaporators in the passenger compartment and allother components under the hood.

Through the 1950s and 1960s, motor vehicle A/C was offeredeither as a factory-installed or as a dealer-installed accessory onselected motor vehicles and as a “hang-on” accessory installedby enterprising automobile service companies. The hang-on A/Csystem was sold as a kit with standardized parts including aninterior console (with evaporator, expansion valve, fan, andcontrols), compressor, condenser, and the custom parts neces-sary to fit the system to a particular vehicle. The model-specificparts include a drive pulley, a compressor drive belt, hose assem-blies, and an assortment of brackets to align the pulleys andattach the various components. The console hung under thedash, the compressor was bolted to the engine, the compressordrive pulley bolted to the crankshaft damper, and the condenserwas mounted below or in front of the radiator. Most kit airconditioners also include the necessary lubricant, CFC-12 refrig-erant, and charging hoses. In hot climates, the engine coolingsystem was often up-sized or fitted with larger cooling fans.

In the 1970s, A/C was increasingly offered as standard equip-ment on motor vehicles or as an option. By 1987, when theMontreal Protocol was signed, A/C was installed on more than90% of vehicles sold in North America and on about 50% ofvehicles sold in Europe and Japan. By 2000, A/C was standardon nearly all vehicles sold in Europe, Japan, and North America,partly because new European and other safety standards fordemisting and defrosting could only be achieved by coolingcabin intake air to dehumidify and then heating the air to providecomfort and defrosting. By 2010, vehicle A/C was standardworldwide on almost all four-wheel vehicles and available asan option on the few vehicles where it was not standard. Today,vehicle A/C consumes 3 to 20% of motor fuel, depending onclimate conditions. Market penetration of mobile air condition-ing in the United States is shown in Table 7.

This A/C fuel use contributes to low fuel economy, localpollution, and global GHG emissions with an estimated 5.5%,3.5%, and 3.2% of total motor fuel consumed in the UnitedStates, European Union (EU), and Japan, respectively. TheUnited States annually consumes about 26 billion liters of fuelfor vehicle A/C, emitting 62 billion kg of CO2 annually (Rugh

et al., 2004). In India, A/C consumes about 20% of automobilefuel as a consequence of heavy traffic congestion throughoutlong, hot, and often humid cooling seasons and where driversprefer windows up to block sound, dust, and pollution (Chaneyet al., 2007). Worldwide, refrigerant emissions accounted forabout half of the air-conditioned motor vehicle life-cycle carbon-equivalent emissions in the 1980s as a consequence of the highGWP of CFO-12 (10,700), leaky design, and service withoutrecovery and recycle (Bhatti, 1998, 1999). The redesign forlower leaks, the new HFC-134a (GWP ¼ 1430) refrigerant,and service using precision leak detection and refrigerant recov-ery and recycle equipment reduced the A/C carbon footprint toless than 8%. As discussed in the following, the transition toHFO-1234yf alone will reduce that to about 5.5% and a pledged30% improvement in A/C energy efficiency will reduce it toabout 3.5% (Rugh et al., 2004).

Andersen et al. (2007) describe the sense of community and themany reasons for cooperation in forming the Montreal protocol:� The theoretical and observational clarity of the science, parti-

cularly the Antarctic Ozone Hole.� The ambition and urgency to protect Earth for future generations

as a precaution against the risk of irreversible consequences.� The Clean Air Act requirement and the U.S. EPA unequivocal

regulatory authority.� The financial reality that phase-out regulations would be

enforced against government operations and infrastructures,including critical uses in military weapon systems and scien-tific research laboratories.

� The recognition that government manufacturing standardsprescribed ODSs use for military, aerospace, telecommunica-tion, and environmental compliance.

� The importance of protecting markets, jobs, and prosperityduring extraordinary market transitions.

1974 to 1978 Mobile A/C community leadership:Reducing A/C system leakage

After Molina and Rowland (1974), U.S. motor vehicle man-ufacturers quietly responded by reducing the refrigerant charge,improving the leak-tightness of A/C systems with better hosesand seals, and reducing CFC emissions from leak testing andrefrigerant charging during vehicle manufacture.

At the same time, CFC manufacturers confidentially investi-gated chemical alternatives to CFCs. Half a dozen companiespatented chemical processes to produce refrigerant HFC-134a,and Allied Signal and Delphi built and road-tested HFC-134asystems, but companies put the technology on the shelf whenregulations only targeted aerosol products (Bhatti, 1999).

1987 to 1988 Mobile A/C community leadership:Commercializing refrigerant recycling under warranty

Automakers argued that the recycled refrigerant should be asclean as newly manufactured CFC. This could require serviceequipment to recover the refrigerant, shipment to an off-sitepurification facility for column distillation, and shipment back

Table 7. ASHRAE refrigerant safety groups

ASHRAE safety group

Lower toxicity Higher toxicity

Higher flammability A3 B3Lower flammability A2 B2

A2L* B2L*No flame propagation A1 B1

Notes: *A2L and B2L are lower flammability refrigerants with a maximumburning velocity of � 10 cm/s.


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

to service facilities. Because CFC-12 was inexpensive (~$2/kg)this scenario presented a difficult or impossible business case.

Service equipment companies with a head start on recyclingequipment design wanted federal regulations to compel its use.But without industry support, it was difficult to reach agreementon federal regulations, and a limited number of recycling equip-ment suppliers provided inadequate competition to serve thepublic interest.

The Mobile Air Conditioning Society and its memberswanted equipment certified to satisfy warranty repair as a signalthat recycling was not a compromise in system durability andreliability, and they wanted environmental organizations toendorse recycling to help technicians sell the now more expen-sive A/C service to their customers.

The U.S. EPA wanted recycling to be simple enough to beimplemented in both large and small service facilities. Theagency shared the concern of automakers and service organiza-tions on system durability and reliability because it would beshort-sighted to implement recycling if contaminated refrigerantcaused components to leak and fail.

An important early technical breakthrough occurred whenParker Hannifin Corporation (a high respected supplier of A/Cfilter dryers) scientifically proved to the satisfaction of automo-bile makers that a new filter would remove any damaging resi-dues. The implication to recycling was that simple filtration andmoisture removal would be adequate and that more elaborateprocessing, such as redistillation, would be unnecessary. Theresearch team discovered that refrigerant was mildly contami-nated in relatively new vehicles, possibly because of manufac-turing quality control or because of the metal residues when newparts are broken in by operation.

The strategy was to agree first on criteria that would satisfy allstakeholders, and later on the technical performance satisfyingthese criteria and the specific test method validating thatperformance:

� Vehicle manufactures would agree to accept under new carwarranty refrigerant with contamination no greater than thatexisting in normally operating A/C systems in automobilesonly a few months old.

� Recycling equipment manufacturers would agree to test theability of their machines against a highly contaminated testsample typical of the worst contamination found in vehicleswith failed air conditioners.

� Underwriters Laboratory (UL) would agree to certify recyclingequipment that could clean the contaminated test sample to theagreed standard of purity when operated in shop-likecircumstances.

� NGOs would agree to promote the new technology to thepublic. Once these agreements were in place, the plan was tohave U.S. EPA propose regulations compelling use of recy-cling equipment and the certification of technicians using theequipment.

This agreement was revolutionary because at the time vehiclemanufacturers had never before accepted used parts or fluids inwarranty repair, UL had never certified the performance of anyproduct (only its safety), and the U.S. EPA had never made

informal agreements with industry that a regulation would beagreed by consensus.

The strategy had the advantage of a global team of experts allworking with a common purpose and each contributing to pro-duct development. For example, the original agreement on thetesting of the contaminated sample had not anticipated that therecycling equipment would need a system to purge nonconden-sable gases (air) from the refrigerant. In service, without recy-cling, the A/C system is merely subjected to a strong vacuum thatremoves all the air from the system and then it is recharged withnew refrigerant with no air contamination.

Recycling equipment draws both refrigerant and air that hasleaked into the A/C system through the filters and dryers to purifythe refrigerant/air mix. To accomplish this, an air-purge system isneeded to discharge the air in its vapor stage while containing therefrigerant in its liquid stage. Because even a small amount of airleft in the system will diminish cooling capacity and increaseenergy use, it was important to err on the side of purity. But erringon the side of refrigerant puritymeant that U.S. EPA and the publicwould have to accept that some CFCwould be discharged into theenvironment. Fortunately, everyone saw the advantage of fastaction and agreed to abide by the agreement to not compromisethe integrity of the system but to continue cooperative work tofurther improve the equipment after first commercialization.

Over a period of one year, the team:

� Conducted statistically significant sampling of refrigerant innormally operating new vehicles (which was validated byconfidential sampling by several of the vehicle manufacturersand service equipment companies).

� Built and tested a wide variety of recycling equipment designswith different sized filters, dryers, vacuumpumps, and controls.

� Authored an SAE J-Standard specifying the performance andsafety of recycling equipment used on vehicles.

At the same time, UL wrote the test procedure to certifyequipment to the SAE J-Standards and the U.S. EPA, industry,and NGOs worked with Congress to specify that the SAE stan-dard and UL certification would be the basis of legislation andregulation compelling recycling. All in all, millions of dollarswere spent perfecting the recovery and recycling equipment.

Environmental organizations fully supported recycling, stateand federal agencies announced proposed regulations makingrecovery/recycling mandatory, and many automobile manufac-turers required their dealers to purchase at least one recyclingmachine. The service equipment companies that had participatedin the cooperative effort sold more than US$2 billion worth ofrecycling equipment within the first two years ($1.5 billionU.S. sales and $0.5 Canadian and global sales), UL more thanrecovered the cost of developing the test procedures, the MobileAir Conditioning Society made substantial progress with its goalof professionalizing A/C service, and consumers became willingto do their part to protect the ozone layer. Friends of the Earthwas the driving force behind environmental NGO support forboth recovery and recycling and for the rapid transition fromCFC-12 to HFC-134a.

Refrigerant recycling, restricting the sale of small cans ofCFCs to certified technicians, and retrofit of some older vehiclesto HFC-134a allowed a faster phase-out of CFCs with a


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

continuous supply available to those buyers willing to pay theprice. CFC-12 prices increased from $2.00/kg in 1987 to $70/kgat the price peak around 2000 and then declined to about $35/kgafter 2005, when few vehicles manufactured with CFC-12 werestill on the road. HFC-134a cost about $13/kg during the 1990 to1994 transition and then declined to about $3.50 to $6/kgbetween 1995 through 2005 (Atkinson, 1989). Higher refriger-ant prices discouraged recharge without repair and encouragedreduced refrigerant charge in new vehicles, which was achievedusing heat exchangers with smaller internal volume and shorterand smaller diameter refrigerant hoses.

The intense engineering efforts to commercialize recyclinghad associated benefits in improvements in both A/C design andservice procedures. Prior to the cooperative effort, vehicles wereoften charged using a sight glass in the tube from the compressorto the evaporator that allowed the technician to see bubbles in therefrigerant flow. The belief was that presence of bubbles indi-cated an undercharged system, or conversely that a bubble-freefluid would show that the system was properly charged. Theresearch team determined that sight glasses were unreliableindicators of proper charge and that the recycling equipmentcould automatically recover whatever charge was in the vehicleand then recharge the amount specified for that vehicle. Theproper charge increases equipment life, reduces energy use, andavoids unnecessary emissions caused when overcharged systemsare vented through pressure relief valves. For manufacturers,removing the sight glass eliminated one system component andtwo connections that could leak.

1987 to 1990 Mobile A/C community leadership:Testing and selecting HFC-134a

Simultaneously with the work on the mobile A/C recyclingagreement, the chemical industry and its refrigerant customersmoved rapidly to commercialize HFC-134a, which had beenidentified and patented more than a decade earlier. It may benoted that the potentially environmentally preferable options ofHFC-152a, CO2, and HFO-1234yf (2,3,3,3-tetrafluoropropene)are only now becoming technically feasible. At that time, CO2

was not considered suitable for use as a refrigerant in vehicle A/Csystems, partly because Gustav Lorentzen kept his technologyconfidential from 1989 when he filed for a patent until 1993when the patent was granted. Flammable refrigerants, includinghydrocarbons and HFC-152a, were not considered because leakrates were too high and discharge of a flammable refrigerantduring service was far too dangerous without fully implementedrefrigerant recovery and recycling. At that time HFO-1234yfwould have been considered far too costly, particularly becausethere was little political appreciation of climate change and littleprospect of near-term restriction on the GWP of refrigerants.

HFC-134a was considered to be the most technically feasiblechoice to replace CFC-12 refrigerant in most A/C and refrigera-tion applications because it was not flammable and had toxicity,pressure, and temperature properties very similar to the CFC-12it replaced. Additionally, its price was only 3–5 times higher thanCFC-12, which was a refrigerant cost increase of as little as $2/vehicle. HFC-134a is ozone safe and has the environmental

advantage of a 100-yr GWP of 1430—eight times lower thanthe 100-yr 10,900 GWP of the CFC-12 it replaced.

The 1987 Montreal Protocol required only a 50% reduction inCFC use, which could have been accomplished in countries withunregulated CFC aerosol products with little technical innovation.The first technical assessment for the Montreal Protocol listedHFC-134a as a potent greenhouse gas likely to be less energyefficient and thus contribute indirectly to greenhouse gas emis-sions from fuel burned to power refrigeration and A/C equipment(UNEP, 1989). In addition, workshops held by UNEP in prepara-tion for the negotiations of the 1985 Vienna Convention and the1987 Montreal Protocol also emphasized climate change topics.The 1991 TEAP report presented recently published estimates ofTEWI, which combine the direct impacts of refrigerant green-house gases and the indirect impacts of the fuel emissions neces-sary to power the equipment (UNEP Ozone Secretariat, 2012).

The American Refrigeration Institute (ARI), the AmericanSociety of Heating, Refrigerating, and Air Conditioning Engineers(ASHRAE), the International Institute of Refrigeration (IIR), andthe Oak Ridge National Laboratory agreed on a full spectrum ofrefrigerant properties and performance testing and made the infor-mation publicly available.

However, a more daunting technical challenge was the neces-sity to test the materials and lubricant compatibility of HFC-134a. Lubricant compatibility with CFC-12 had been throughtrial and error decades earlier, there was no accepted scientificmethod for testing compatibility, and the few existing compat-ibility testing experts were spread among competing organiza-tions that had no history of cooperation.

Corporate members of the U.S. Motor Vehicle ManufacturersAssociation (MVMA) appreciated the value of cooperation inavoiding duplication of effort and in achieving a critical mass offocused engineering talent, but corporate attorneys warnedagainst any collaboration that might raise antitrust concerns.The MVMA solution was to use the National CooperativeResearch Act (NCRA) of 1984 (NCRA, P.L 98–462) to reducepotential antitrust liabilities of research joint ventures. The ideaof the NCRAwas to guarantee that the “rule of reason” standardwould be a mitigating factor in any antitrust investigation if thepurpose and conduct of the research were clearly in the broadpublic interest (Link and Scott, 2001; Scott, 2008).

On 30 July 1987, the MVMA and the U.S. EPA were regis-tered as a technology cooperation consortium under the NCRAfor “Fluorocarbon-134a lubricants for mobile A/C systems” andsubsequently the consortium was able to conduct successfullyguided and coordinated testing (Gibson and Smilor, 1992).

The MVMA strategy was so legally impressive that the aero-space and electronics industries created the Industry Cooperativefor Ozone Layer Protection (ICOLP) and the fire protectionindustries created the Halon Alternatives Research Consortium(HARC) under the NCRA. Noteworthy is that MVMA, ICOLP,and HARC included foreign companies that were able to coop-erate in ways that may not have been allowed in their homecountries.

In 1990, vehicle manufacturers in Europe, Japan, and NorthAmerica made coordinated announcements that HFC-134awould be the refrigerant of choice for mobile A/C. One measureof the urgency of ozone layer protection and the confidence of


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

industry and environmental authorities in HFC-134a is that, atthat time, toxicity studies were not yet complete, HFC-134a wasnot approved under the U.S. EPA Significant New AlternativePolicy (SNAP) program, and there were no HFC-134a manufac-turing plants under construction (Atkinson, 1989). Within amonth of the global mobile A/C choice of HFC-134a, five globalchemical manufacturers announced commercialization andbegan HFC-134a manufacturing plant construction. Theseannouncements encouraged manufacturers of stationary refrig-eration and A/C equipment to accept HFC-134a, partly becausethe mobile A/C market was large enough to assure economies ofscale and competitive prices.

By 1995, the mobile A/C sector accomplished the first globalsector phase-out of the use of CFC-12 in refrigeration and A/Cequipment, with conversion completed for the vast majority ofnew car manufacture in almost most countries. The last compa-nies in China and India halted the use of CFCs in new vehicle A/C in 2002 and 2003, respectively.

Rapid commercialization and market domination of HFC-134a not only eliminated a large portion of ODS emissions, butalso built contagious confidence in the ability for new technol-ogy to be invented, demonstrated, approved by regulatory autho-rities, and welcomed into markets. Entrepreneurs within thefluorocarbon industry faced such stiff competition from non-fluorocarbon solutions that, in the end, only 15% of processesand products sold today that once depended on ODSs nowdepend on fluorocarbon solutions.

The 1993 disclosure of the Lorentzen CO2 system capturedthe imagination of engineers at Daimler and a few other vehiclecompanies who wanted to eliminate HFC refrigerants withoutadversely affecting cooling performance or fuel efficiency. In1994, CO2 advocates found strong support from the EuropeanCommunity Industrial and Materials Technology Program,which funded the “Refrigeration and Automotive Climateunder Environmental Aspects” (RACE) program.

The consortium adopted CO2 as the most technically andeconomically feasible option, and in just three years, RACEadvanced the technology and built two working prototypes fora BMW 520i and a VW Polo (ECCRDIS, 1997). One out-come of the cooperation was a joint patent by BMW andDaimler for a CO2 vehicle A/C system that was designed tocool and also to heat vehicles lacking waste heat from internalcombustion engines, such as plug-in hybrid, electric, or fuelcell vehicles. The heat pump technology would also heatconventionally powered vehicles faster than waiting for theengine to warm up.

In 1997, RACE presented its results at the Earth TechnologyForum in Washington, DC, and, in 1998 brought the prototypesto Phoenix, AZ, for an informal meeting with global industryleaders. The Phoenix “ride and drive” testing confirmed coolingperformance. In Phoenix, the RACE member companies trans-formed the European consortium into the “Phoenix Forum”withSAE sponsorship, global participation, and a wider agenda thatcreated healthy competition among several options:

� Enhancing the existing HFC-134a systems.� Choosing the low-GWP HFC-152a refrigerant as a near drop-

in replacement.

� Taking the revolutionary leap to the entirely new CO2

technology.

At the 1999 meeting of the Phoenix Forum, participants organizedthe Mobile Air Conditioning Climate Protection Partnership(MACCPP) (U.S. EPA, 1999b) with a mission statement to reducerefrigerant greenhouse gas emissions by at least 50% (achievingless than 20 g per year emissions) and A/C fuel consumption by atleast 30%. The partnership teamed up with the SAE’s AlternativeRefrigerants Cooperative Research Program (CRP), and withU.S. EPA and the U.S. Department of Energy’s NationalRenewable Energy Laboratory (NREL) on cooperative projects toenhance the environmental performance HFC-134a mobile A/C.

In 2000, European national and EC environmental authoritiesbegan serious consideration of controls on HFCs and five otherGHGs (CO2, CH4, N2O, PFCs, and SF6). The EC saw the advantageof harmonized global regulation and invited participation of environ-mental and industry associations, notably theU.S.EPA,SAE, and theMobile Air Conditioning Society. This collaboration led to severalimprovements in the proposal including allowing HFC-152a (GWP124), shifting thephase-out date to 2017, and considerationof energyefficiency in addition to a refrigerant GWP limit.

Meanwhile, by 2001, Daimler engineers were confidentenough in CO2 technology to recommend it to management forthe redesigned S-Class Mercedes Benz, which already had manyof the sophisticated monitors and controls necessary to operatethe more complicated CO2 system. However, in late 2002,Daimler chose to delay introduction because the system suppli-ers bid higher than the company reservation price and because,despite lobbying for HFC regulation by Daimler, the EuropeanCommission (EC) was unable to confirm its intentions either tocontrol HFC-134a or to reward HFC-free systems (Andersen andZaelke, 2003). However, in December 2002, Toyota’s fuel-cellhybrid vehicle was launched for street testing with a Densoelectrically driven, hermetically sealed air conditioner and heatpump using CO2 refrigerant.

In February 2003, executives of the EC concluded after twodays of technical presentations that “HFC-134a is an unsustain-able option for mobile A/C that could be phased out within thedecade.” The final EC “F-gas Directive” proposed in August2003, and agreed in May 2006 (Directive 2006/40/EC of theEuropean Parliament and the Council), that air conditionerssold on new “type” vehicles in the E.U. after 2010 and all vehiclessold in the E.U. after 2017 use refrigerants with 100-yr GWP< 150.

The original EC proposal included additional incentives andflexibility that were removed at the request of European vehiclemanufacturers. These incentives included an elegant combina-tion of transferable quotas and credits and a “safety valve” thatwould have allowed vehicle manufacturers to pay 100 euros foreach vehicle sold if they were unable to meet the deadline forparticular models. One HFC-134a credit was to have beenearned for every two “Enhanced 134a Systems” sold prior to2014, with enhanced systems defined as having less than 20 gemissions for single evaporator systems and less than 25 gemissions for systems with a double-evaporator; one credit isearned for each “alternative system” (CO2, 152a, or HC) soldprior to the start of phase-out.


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

At the time of the 2006 EC announcement, the only publiclydisclosed refrigerants satisfying the criteria of GWP < 150 werehydrocarbons (GWP ~5), CO2 (GWP¼ 1), and HFC-152a (GWP~124). However, within weeks of the EC F-gas Directive, morethan five international chemical manufacturers—including Asahi,Arkema, DuPont, Honeywell, Ineos, and Sinochem—announcednew fluorocarbon refrigerants with GWP below 150. Soon itbecame clear that the most suitable of the candidate fluorocarbonswas hydrofluoroolefin (HFO)-1234yf, which has aGWP~4 and iscomparable in toxicity to CFC-12 and HFC-134a, but is mildlyflammable. Refrigerants are classified by American NationalStandards Institute/American Heating, Refrigerating, and Air-Conditioning Engineers (ANSI/ASHRAE, 2007; ANSI/ASHRAE, 2010) into a matrix diagram of safety groups, consid-ering flammability and toxicity. Table 8 shows the definition ofASHRAE toxicity and flammability groups. HFC-32 and HFO-1234yf are group A2L (lower flammability and toxicity), whileHC-290 and HC-600 are group A3 (higher flammability andlower toxicity).

For the next five years, CO2 and HFC-152a competed withHFO-1234yf. Despite their low GWP and very low cost, hydro-carbons were never seriously considered by any major auto-maker, and advocates of hydrocarbons never organized thetechnical teams necessary to achieve U.S. EPA SNAP approval.HFC-152a was first to be SNAP listed for mobile A/C in June2008 (U.S. Federal Register, 2008), HFO-1234yf was SNAPlisted for mobile A/C in March 2011 (U.S. Federal Register,2011), and CO2 was SNAP listed for mobile A/C in June 2012(U.S. Federal Register, 2012).

Because HFC-152a is mildly flammable and HFO-1234yf ismildly flammable, SNAP requires that safety hazards be miti-gated in accordance with SAE design standards, which limitrefrigerant charge and isolate potential leaks from sources ofignition. Because CO2 can asphyxiate or diminish driver capa-city, SNAP requires that system designs ensure that a short-termconcentration of 15 minutes or more is <3000 ppm CO2 and that4000 ppm CO2 is never reached, and that risk be mitigated inaccordance with SAE design standards, which limit refrigerantcharge and keep refrigerant from occupied spaces.

HFC-152a has the advantages of a low GWP (124), energyefficiency significantly higher than HFC-134a, low price fromexisting chemical manufacturing facilities, and its patents haveexpired so it can be competitively produced by a wide range ofsuppliers. The challenge was to quantify the risk of the refriger-ant reaching flammable concentrations in the passenger

compartment. U.S. Army experts on the team had faced similaranalytical challenges in designing armored vehicles to reduce therisk of fuel and other flammable fluids during normal operationsand combat. They adapted computational fluid dynamics (CFD)models to calculate the characteristics of the worst-caserefrigerant-air mixture for a plume from an A/C evaporatorunder the vehicle dashboard. This work confirmed that a con-ventional A/C system would be unsafe with HFC-152a refriger-ant but that a redesigned system would be safe if the refrigerantwere kept out of the passenger compartment or if the quantityand rate of discharge into the passenger compartment were keptwithin safe limits.

The HFC-152a design team identified several mitigationstrategies for the safe use of HFC-152a. The safety mitigationstrategy—called a “secondary loop”—uses an under-hood heatexchanger where the flammable refrigerant cools a nonflam-mable fluid that is then circulated in the second loop to anunder-dash heat exchanger. In this design the refrigerant canleak only into the engine compartment, which is heavily ventedby the cooling fan and vehicle movement. The second safetymitigation strategy places a reliable electronic sensor in thechamber around the evaporator to detect refrigerant leakageand trigger a valve that discharges the refrigerant charge harm-lessly away from the vehicle occupants. Both strategies requirethat A/C components in the engine compartment be isolatedfrom ignition sources.

The secondary loop safety strategy has the advantage of beinga fail-safe design that requires no action by the driver or passen-ger. The leak detector safety system has the disadvantage ofrequiring a reliable leak detector that accurately identifies aserious release, but avoids false positives. The secondary loopsystem has the advantage of using the thermal ballast of thesecondary loop fluid to continue cooling the vehicle when theengine is stopped to save fuel at intersections or in congestedtraffic. The “idle stop” feature on hybrid and conventional vehi-cles is usually active when temporary loss of cooling is accep-table to passengers.

HFO-1234yf has the advantage of very low GWP, energyefficiency comparable to HFC-134a, and low toxicity. It hasthe disadvantages of high price, slight flammability, limitedproduction facilities, and patents by Honeywell claiming exclu-sive right to manufacture or license the manufacture despite atleast five chemical companies having patented chemical path-ways in manufacture.

HFO-1234yf is so difficult to ignite that it need not be keptfrom occupied spaces where there are no high-energy sourcesof ignition, but A/C components, including hoses, in the enginecompartment must be physically separated from sources ofignition. Refrigerant from a leak must not contact hot exhaustparts or electrical sparks from the ignition system or relays.HFO-1234yf is similar in toxicity to CFC-12, HFC-134a, andHFC-152a. HFC-1234yf also has the undesirable atmosphericfate of producing trifluoroacetic acid (TFA), a naturally occur-ring substance, which will be increased in concentration unlessHFO-1234yf refrigerants are contained without leakage. Thescientific assessment panels of the Kyoto and MontrealProtocols have judged that future concentrations of TFA willnot pose a significant environmental risk, even if HFO-1234yf

Table 8. Best-in-class and worst-in-class mobile A/C refrigerant leakage (g/yr)by vehicle type

Vehicle typeBest-in-

class 2009Best-in-

class 2012Worst-in-class 2012

Minivan 12.8 8.7 23.7Passenger cars 7.0 5.9 21.9Pickup trucks 9.4 9.6 17.4SUVs 8.5 8.2 28.2Full-sized vans 10.1 10.1 25.7


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

replaces all current applications of HFC-134a (Metz et al.,2005; SAP, 2010).

CO2 has the advantages of low GWP, nonflammability (infact, a fire-extinguishing agent), and wide availability at lowcost. It has the disadvantage of low cooling capacity and highenergy consumption when operating at high ambient tempera-tures whenA/C is most needed. There are few specific patents onoverall design and on specific components. CO2 at low concen-trations may cause neurotoxin effects such as drowsiness, dis-traction, and increased reaction time that diminish drivercapacity in ways similar to alcohol or drug use. In the UnitedStates and many other countries health and environmental autho-rities consider both asphyxiation and neurological effects, butthe EC only officially considers asphyxiation risk.

The CO2 cooperative design team identified several safetymitigation strategies, including detection and discharge and theuse of a stenching gas. As in the case of HFC-152a, the leakdetection must sense release without false positives. This iscomplicated in the case of CO2 because normal air contains350 ppm CO2 with substantial variability from nearby emitters,including other engines and human exhalation.

The stenching gas strategy (based on distinctive unpleasantodor) faced uncertain regulatory hurdles in proving it was safe,proving that it was compatible with lubricants and materials, andproving that people would respond appropriately to the smell(roll the windows down and stop and exit the vehicle). Thestenching proposal failed because all the stenching agents testedwere absorbed in the A/C lubricating oil and lost the telltalearoma within weeks.

U.S. barriers to the adoption of low-GWP energy efficientrefrigerants proved indicative of the situation in most developedcountries:

� Department of Transportation accumulator pressurerequirements.

� State bans on toxic and flammable auto A/C refrigerants.� Occupational Safety and Health Administration (OSHA)

requirements for training, personal protective equipment,safe handling, pressure relief devices, equipment inspection,worker exposure, ventilation, and refrigerant storage.

� U.S. EPA Significant New Alternative Program (SNAP) andToxicity Program review.

� National Highway Traffic and Safety Administration(NHTSA) requirements.

In some cases barriers were removed by administrative decisionbased on technical information provided by the MACCPP teamand reviewed by government authorities. The U.S. Departmentof Transportation waived the accumulator pressure requirementwith an interpretation: “[Air conditioning systems] are an inte-gral component of a motor vehicle and necessary for the opera-tion of the vehicle” and “Based on the information you provided,the air conditioning system . . . is not subject to the HazardousMaterials Regulation” (Gale, 2006).

In another application of administrative decision, OSHAdeclared that SAE J-Standards for servicing CO2, HFC-152a,and HFO-1234yf mobile A/C systems would satisfy require-ments for training, personal protective equipment, safe handling,pressure relief devices, equipment inspection, worker exposure,

ventilation, and refrigerant storage. One advantage of OSHAciting the SAE standard is that SAE updates in response toaccident experience or revised engineering calculations imme-diately have the full effect of law.

In 2006, 18 U.S. States and the District of Columbia had lawsthat banned flammable refrigerants, often without defining orspecifying what was toxic or flammable, and 12 states bannedtoxic refrigerants. It was important to remove state bans on toxicand flammable refrigerants because HFC-152a and HFO-1234yfare flammable and CO2 is toxic. These state bans were mostlyenacted in the early 1990s when unethical and unscrupulousentrepreneurs were trying to take advantage of the public desireto protect the stratospheric ozone by marketing highly flam-mable and sometimes toxic refrigerants for recharge of vehicleair conditioners designed for CFC-12.

The strategy in removing these state barriers was to assemblea government–industry team of respected authorities to createsafety standards that would allow the safe use of refrigerantslisted under the U.S. EPA SNAP regulation. The Alliance ofAutomobile Manufacturers and the Association ofInternational Automobile Manufacturers (now renamed as theAssociation of Global Automakers) were particularly influential.The team developed a comprehensive list of states with specificbarriers, determined which could be removed by administrativeruling and which would require new legislation, identified one ormore key points of contact, and assembled the technical andenvironmental justification for the proposed changes.

One by one, over a period of about three years, these outrightbans were either removed or replaced. The typical regulation repla-cing the outright prohibition used a combination of U.S. EPA andSNAPapproval adherence to SAE J-Standards for health and safety,specific exemption from the ban on flammability forHFC-152a andHFO-1234yf, or clarification that the ban on flammable refrigerantsapplied only to hydrocarbons.

The mobile A/C LCCP system model (Hill and Papasavva,2005) became the starting basis for the SAE Interior ClimateControl Committee working group that developed and dissemi-nated a global template for corporate, government, and publicuse. The LCCP harmonization activity was opened to the entireautomotive industry in 2006 with strong participation of SAE,Verband der Automobilindustrie (VDA, the German Associationof the Automotive Industry), and Japan AutomobileManufacturers Association (Papasavva et al., 2008). Papasavvaand Hill—with a global team of 50 world experts from 32industries representing governmental and nongovernmental orga-nizations, national laboratories, and academia—perfected andcontinuously improved their LCCP model, with input and datafrom automobile manufacturers and suppliers and by includingstate-of-the-art cabin comfort conditions using modeling resultsprovided by participants from the NREL (Johnson, 2002).

The public domain model—named GREEN-MAC-LCCP—uses globally harmonized data and assumptions, and provides amore realistic application of the engineering data obtained frombench tests because it applies them to various driving cycleengine conditions. Most of the input data are fixed and basedon the harmonization process (U.S. EPA, 2009). This preventsmanipulation of the modeling process to influence results tobenefit a particular technology and makes sure that comparisons


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

are fair. Only a small amount of input data is required to run themodel, which is unique to each refrigerant such as its GWPvalue, its system efficiency, and so on. The model allows theuser to enter coefficient of performance (COP) and evaporatorcooling capacity data obtained by laboratory bench-test experi-ments that were confirmed by consensus of the SAE StrategicAlliance, and the SAE Interior Climate Control Committee(SAE, 2004).

GREEN-MAC-LCCP analyzes up to six alternative refriger-ants and compares them with a fixed HFC-134a baseline. Modeloutput results provide annual and lifetime LCCP CO2-equivalentper vehicle for 67 world cities and lifetime LCCP CO2-equiva-lent for global fleets in various world regions. For each city, theuser can select among three different vehicles (small, midsize,sport-utility), and four alternative fuels (gasoline, diesel, ethanol,and methanol). The model is also flexible to analyze LCCPGHGemissions from global fleets running with A/C on, for any givenyear during 2008–2017.

GREEN-MAC-LCCP has become the global standard metho-dology for assessing the climate impact of mobile A/C systemsand has been approved as an SAE technical standard (SAE J-2766).

To reduce refrigerant emissions it was necessary to first esti-mate those emissions—what gets measured is what gets managed.Previous analysis by the IPCC/TEAP had estimated the portion ofglobal HFC emissions from vehicle A/C, and previous analysis bythe EC had estimated vehicle refrigerant leak rates.

The IPCC/TEAP had used a “top-down” approach that recon-ciled atmospheric concentrations of HFC-134a against thereported annual global manufacture of HFC-134a and allocatedemissions by sector using best available judgment (Metz et al.,2005). Analysis commissioned by the German Ministry ofEnvironment (MoE) and the EC had used a “bottom-up”approach that subtracted the amount of refrigerant recoveredfrom an A/C system from the charge amount at the time ofmanufacture, and divided by the age of the vehicle to yieldannual leak rate (Schwartz, 2001; Siegl and Wallington, 2002;Schwartz and Harnisch, 2003). The German MoE and the ECstudy used unrepresentative samples, questionable assumptionsabout vehicle repair history, and uncalibrated recovery equip-ment and scales, all of which likely biased the results.

The partnership undertook a more scientific “bottom-up”approach by analyzing confidential records of warranty repairfor new vehicles and service records for large vehicle fleets, andby surveying Mobile Air Conditioning Society members, toreport the refrigerant use in service for vehicles no longer receiv-ing warranty repair from manufacturers. In addition, an engineerfrom GM designed an experiment to precisely charge usedvehicle A/C systems to the amount recommended by the manu-facturer and later subtract the amount of refrigerant recoveredfrom the system to quantify the amount that had leaked out.

As part of the test protocol, it was discovered that recoverymachines did not recover the full amount of refrigerant justcharged into a completely empty A/C system. These resultswere confirmed on variety of vehicles using different recoverymachines, including brand new equipment. The explanation wasthat a portion of the refrigerant charge remains in the system—

absorbed in the oil and trapped in system components even after

being subject to the strong vacuum of a recovery machine. Theimplication was that the EC analysis overestimated the emissionrates by the amount not recovered and that the recovery equip-ment standard needed to be revised to provide a stronger vacuumfor a longer period of time.

The new HFC-134a recovery/recycling/recharging (RRR)equipment standard SAE J-2788 requires 95% refrigerant recov-ery, compared to 50–75% recovery from the older equipmentdesigned to SAE J-2210 (SAE, 2013). The new SAE standardfor electronic leak detectors increases their leak detection sensi-tivity from 14 g per year to 4 g per year, which allows techniciansto confirm that repairs are as leak-tight as possible.

The SAE J-2834 standard for HFO-1234yf RRR equipmentrequires not only high efficiency of refrigerant recovery but also anew two-step process to avoid rechargewithout repair. In the questfor improved HFC-134a systems, SAE also developed the J-2727standard for estimating new vehicle refrigerant leak rates based onthe quality of components, permeability and length of refrigeranthoses, the number of connections and ports, and seal design.Manufacturers publish the estimated leak rate for all vehiclessold in Minnesota (Minnesota, 2008; MPCA, 2011). Later,California required J2727 as the basis for achieving a fleet averagerefrigerant leak rate of less than 9 g per year in compliance with“LEV III A/C Requirement 2: Fleet Average Leak Rate� 9 g/yr”(CARB, 2012). MPCA (2011) data indicate dramatic improve-ments between 2009 and 2012 best-in-class leak rates for mini-vans and passenger automobiles but little progress in pickuptrucks, sport-utility vehicles (SUVs), and full-sized vans. This isshown in Table 8. The MPCA data indicate that if all manufac-turers achieved the leak rates of the best-in-class, total fleet emis-sions could be reduced by about half.

Until recently, energy use for A/C, power steering, and alter-nators, as well as rolling resistance and aerodynamics, has notbeen part of automobile fuel efficiency tests and has not beenfactored into fleet mileage standards or fuel mileage labels. Withno specific testing of A/C refrigerant use, manufacturers hadlittle incentive to spend more on improved A/C systems.Outsourcing contracts for A/C systems specified cooling capa-city, reliability, noise, and vibration, but not energy efficiency.Many A/C systems were designed to operate at full coolingcapacity and to control comfort by reheating the air, as needed,rather than controlling the system to provide the desired coolingcomfort with the least amount of energy.

Increasing mobile A/C fuel efficiency can make a consider-able contribution to reducing CO2 emissions because 3 to 20% ofvehicle fuel use is for A/C, demisting, and defrosting. If auto-makers achieved the MACCPP goal of a 30% increase in fuelefficiency worldwide, the annual savings would be 26 billionliters (7 billion gallons) of fuel in the United States, 6.9 billionliters (1.8 billion gallons) in Japan, and 20 billion liters or morein the rest of the world.

When increased fuel efficiency became a priority, engineersidentified new technologies including microchannel heat exchan-gers, computer-controlled electronic expansion valves, better air-flow, and component optimization.

Toyota engineers determined that a variable displacementcompressor controlled by the engine control module couldsave energy with “regenerative cooling,” which increases


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

compressor displacement during deceleration to cool theevaporator and controls interior comfort by adjusting thevent fan speed. When the vehicle is not decelerating, thecompressor only provides cooling if the evaporator is toowarm to maintain comfort levels with the engine controlmodule programmed to increase compressor displacementwhen the engine can provide the power with the leastamount of fuel (for example at constant vehicle speed ratherthan during acceleration). Toyota has achieved up to 50%reduction in A/C fuel use with this strategy alone.

GM engineers determined that window defogging could beachieved with less fuel use by controlling the evaporator tem-perature to more efficiently dehumidify the air being directed tothe windows.

NREL applied integrated modeling, assessments of opti-mized techniques to deliver conditioned air to vehicle occupants,thermophysiological modeling, and studies of waste-heat cool-ing and heating opportunities (Rugh and Farrington, 2008), andthe following approaches emerged:

� Reduce the thermal load by using solar-reflective glass orshades and parked-car ventilation.

� Incorporate low mass, naturally ventilated seating (or activeclimate-control seating).

� Consider advanced cabin insulation and solar reflective paintto minimize solar heat gain.

� Incorporate the most efficient refrigerant and A/C compo-nents available.

� Maximize the use of recirculated air, considering air quality,dehumidification, and safety issues, while avoiding windowcondensation.

� Eliminate the overcooling and subsequent reheating of airwith automatic control systems.

Delphi engineers determined that the improved energy effi-ciency of the refrigerant-to-fluid heat exchanger located in theengine compartment in a secondary-loop A/C system could off-set the energy required for the additional liquid-to-air heatexchanger in the passenger compartment. They also figuredout that the thermal mass of the secondary loop fluid can beused to extend the interval of cooling during idle stop, thusavoiding restarting the engine only to provide A/C.

GREEN-MAC-LCCP determined that HFO-1234yf andHFC-152a systems would provide lower life-cycle carbon foot-prints for vehicles operating in all but the mildest climates, whereCO2 systems had a slight carbon footprint advantage.

The MACCPP (Weisler 2009) concluded in 2008 that HFO-1234yf is the refrigerant of choice to replace HFO-134a in motorvehicle A/C and in 2009 announced “cooperation aimed ataccelerating the commercial introduction of improved A/C sys-tems in U.S. and global markets using refrigerant HFO-1234yfwhich can significantly reduce the carbon-equivalent emissionsof greenhouse gases while increasing vehicle fuel efficiency”(VASA, 2009). The decision came just two years before the first“new type” vehicles would require a refrigerant with GWPbelow 150 in order to be sold in the EU.

In spite of some potential advantages, the motor vehicleindustry did not select CO2 as the new refrigerant of choicebecause of higher energy requirements, difficult leak testing in

air with 350þ ppm CO2, poor reliability, and high cost. CO2 hasmuch higher operating pressures and that would require a com-plete reengineering of mobile A/C systems to deal with the highpressures—at great cost to the industry both for initial introduc-tion and as a continuing manufacturing requirement.

In the United States, the U.S. EPA now offers a credit for alow-GWP refrigerant like HFO-1234yf toward CorporateAverage Fuel Economy (CAFE). In Japan, the quantities ofHFC-134a available to vehicle manufacturers are restricted,which creates incentives to minimize system mobile A/C systemcharge, and recovery at vehicle disposal is paid from a depositpaid on new car sales (like recycling deposits on the sale of newtires and batteries).

In Australia, there is a new tax on the imports of greenhousegas refrigerants in bulk or contained in products that acts as anincentive to minimal use and emissions and as a source offunding for recovery, reuse, and destruction.

Progress and setbacks

Unlike the four-year global transition from CFC-12 to HFC-134a, the transition from HFC-134a to HFO-1234yf has beenfraught with complications, even as public and policy supportgrows for a global transition to HFO-1234yf.

Honeywell legal claims of patent monopoly slow HFO-1234yfuptake, but its monopoly is gradually weakened by litigation.A legal complication, which slowed technical progress, wasinitiated in 2009 by Honeywell claiming “application patents” inEurope (EP 2 163 592 A2) and the United States (U.S. Patent,2004) for the use of HFO-1234yf as a refrigerant. If granted, suchclaims could result in monopoly profits and inadequate supply thatcould slow the adoption and useworldwidewhile increasing costs.

U.S. environmental NGOs petition U.S. EPA to remove HFC-134a from the list of acceptable refrigerants for mobile A/Cs. InMay 2010, the Natural Resources Defense Council (NRDC), theInstitute for Governance & Sustainable Development (IGSD),and the Environmental Investigation Agency (EIA) petitionedU.S. EPA under the SNAP program to remove HFC-134a fromthe list of acceptable substitutes for CFC-12 for use in motorvehicle air conditioners. On February 14, 2011, U.S. EPAannounced that the petition was complete for new passengercars and light duty vehicles and that U.S. EPA has the authorityto revise this list on its own, or in response to a petition, toremove a substitute previously listed as acceptable. A likelyoutcome would to be a U.S. phase-down no faster than pre-scribed by the EC F-gas Directive.

The Japanese earthquake and tsunami destroy the Asahi HFO-1234yf production facility supplying HFO-1234yf to Honeywell/DuPont customers and a cumbersome regulatory process slowsthe construction of the Chinese DuPont/Honeywell HFO-1234yffacility. In late 2011, DuPont and Honeywell—the only chemicalsuppliers legally allowed to supply HFO-1234yf under theHoneywell monopoly application patents—notified the EC thatthey were unable to supply the quantities of HFO-1234yf


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

necessary for companies to comply with mobile A/C F-gasDirective because the refrigerant production facility in Japan hadbeen disrupted by the earthquake and tsunami, and the facility formass production in China had been delayed by an unexpectedlycumbersome regulatory approval process. In March 2012, the ECdecided to allow vehicles to use HFC-134a until adequate quan-tities of HFO-1234yf became available, and with a definitivelimitation on 31 December 2012, if refrigerant HFO-1234yf isnot available, provided that vehicles are fitted with mobile A/Csystems that are compatible with Directive 2006/40/EC (ECEID-G, 2012).

The high prices and unreliable supply of HFO-1234yf hadconsequences to the automobile manufacturers that were forcedto slow product introduction; to the suppliers of mobile A/Csystems and components; to the suppliers of custom recyclingequipment, leak detectors, and other tools only useful in servi-cing HFO-1234yf systems; and, of course, to the protection of theclimate. The suspension of enforcement of the EC mobile A/CDirective as a consequence of refrigerant shortage weakened theconfidence of companies depending on clarity and reliability ofregulation and reliable chemical supply.

Daimler Announces Mercedes-Benz automobiles unsafe withHFO-1234yf. On September 25 Daimler (2012) reported that anew vehicle crash study demonstrated that HFO-1234yf ignitedwhen discharged onto hot exhaust pipes. Daimler went on toannounce that HFO-1234yf will not be used in its automobilesand that it intended to revert to HFC-134a for the immediatefuture, which after 1 January 2013 will be a violation of the F-gasDirective. On September 28, 2012, Mercedes-Benz announced avoluntary safety-related recall of U.S. vehicles equipped withHFO-1234yf systems (MACS, 2012).

As part of its normal ongoing product testing, DAG(Daimler AG) subjected a vehicle not sold in theU.S. to a test program designed to replicate worst-case conditions which exceed normal industry andgovernmental test standards. During this testing,DAG became aware that in the event of a severefrontal impact that would also cause a rupture ofthe refrigerant line, there is a possibility that therefrigerant may ignite in the engine compartmentunder these worst-case conditions. Under normaltemperature and operation conditions the refrigerantdoes not ignite. (Mercedes-Benz, 2012)

The Daimler announcement is inconsistent with the unequivocalsafety endorsement presented twoweeks earlier “on behalf of theGerman manufacturers and VDA” that endorsed HFO-1234yf as“a new, safe and environmentally friendly refrigerant” for mobileA/Cs and went on to elaborate:

“Ignition of R1234yf is nearly impossible in the enginecompartment considering operating conditions of thevehicle.”“Ignition of R1234yf is impossible inside the vehicle cabin inreality.”“Ignites only at presence of an open flame or high energyspark.”

“Inflammability observed only when sprayed on hot surfacesabove 900�C (pure R1234yf) (or) 700�C (with 3 percent PAGlubricant)” (Hammer et al., 2012).

At the time of the Daimler announcement, five automakers werereported to each have at least one model with HFO-1234yfsystems and two other companies nearing production. DuPont,Honeywell, and GM publically defended the safety of HFO-1234yf, but other automakers have been mostly silent (Gaved,2010; GM 2010). In October, SAE launched a new CooperativeResearch Program (CRP) to further analyze the safety of HFO-1234yf. CRP participants include Audi, BMW, Chrysler,Daimler, Ford, GM, Honda, Hyundai, Jaguar Land Rover,Mazda, PSA, Renault, and Toyota.

In early December 2012, SAE reaffirmed that its 2009 reviewhad concluded that HFC1234yf “is a safe and acceptable alter-native refrigerant for mobile air conditioning systems that can beused to meet new environmental and consumer needs” andreported that “the majority of the OEMs involved in the newCRP do not believe that any of the new information reviewedwill lead to a change in the overall risk assessment” (SAE, 2012).

Later in December, the EC reaffirmed its conclusion thatHFO-1234yf is safe to use and rejected Daimler’s request for adelay in the transition to refrigerants with GWP less than 150:

Detailed risk assessments and standardisation pro-cesses were conducted with this objective, involvingall manufacturers, which concluded that the risk ofthe use of this gas was equivalent or inferior of otherflammable fluids used in vehicles, including gaso-line. (EC, 2012)

In March, the EC reiterated its intention to strictly enforce theMACDirective and strengthened its resolve to enforce law, stating,“According to Framework Directive 2007/46/EC, it is not possiblefor motor vehicles to be registered and marketed in the EU if theyare not in conformity with the relevant legislation” (EC, 2013b).

On April 23, 2013 the SAE concluded that: “…the refrigerantrelease testing conducted by Daimler is unrealistic…TheDaimler testing did not include any actual vehicle collisions orthe mitigating factors that occur in an actual collision. Thesefactors include the quenching effect of front end compartmentdeformation, the extinguishing effect of steam released due toradiator breakage, and dispersion of the refrigerant from thecondenser outside the engine compartment. Daimler’s refrigerantrelease apparatus and nozzle does not represent actual crash-damaged refrigerant lines, and was found to be artificial.” (SAE,2013a).

Currently, most motor vehicle manufacturers, the U.S. EPA,SAE International, and a number of environmental NGOs allagree that HFO-1234yf is safe. Manufacture is under way, andplans to use it as the “new MAC refrigerant” are moving ahead.

Lessons and Conclusions from RefrigerantTransitions in Motor Vehicle A/C

Without the Montreal Protocol and the national actions thatpreceded it, an estimated two-thirds of the ozone layer would be


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

depleted by 2065 and climate change would have been acceler-ated. The Montreal Protocol is succeeding at protecting thestratospheric ozone layer and in helping protect the climatebecause of global public and political support, stringent treatycontrols and national legislation, financing of the incrementalcosts of phase-out in developing countries, and extraordinarytechnical progress fostered by strong industry–governmentcooperation.

Environmentally acceptable alternatives and substituteshave been globally commercialized and used for each ofapproximately 240 industry and military sectors that wereonce dependent on ODSs. Every United Nations state is amember of the Montreal Protocol and every country is in fullcompliance. Ninety-eight percent of ODS production and con-sumption of nearly 100 industrial chemicals has been phasedout to the satisfaction of public, corporate, and governmentstakeholders. The transition has been so smooth that scienceskeptics are silent, few scholars find fault with the treaty or itsimplementation, companies and military organizations areproud of what has been accomplished, and consumers havehardly noticed.

These stratospheric ozone protection and reduction of climateforcing gas emissions successes were accomplished in manysectors of industry. Automobile manufacturers and service asso-ciations worldwide have been strong supporters of stratosphericozone protection for more than 25 years of both breakthrough andcontinuous improvement in leak-tightness, refrigerant transition,and best service practices. United States-based organizations—particularly SAE, the Mobile Air Conditioning Society, and theautomobile manufacturers associations—have been technologypathfinders to the world. Industry–government cooperation wascritical in recovery and recycling equipment development,approval, and commercialization; fast introduction of HFC-134a; and redesign of A/C systems for lower total charge, andlower annual and life-cycle leakage. Restricting the sales of CFC-12 to certified technicians reduced emissions by at least 50% andincreased the reliability and operating energy efficiency of thenew systems.

Unanticipated consequences of theMontreal Protocol includethe current recognition of the need to phase out HFC-134a only20 years after its introduction and acceptance as the “ultimate”A/C refrigerant gives cause for concern. There were also con-spicuous failures to minimize HFC-134a emissions and to pre-vent refrigerant contamination during recycling. Worldwide,emissions of HFC-134a would be far less if environmentalauthorities required and enforced the use of best available controltechnology (BACT) for refrigerant components and seals,required and enforced frequent upgrades to the most efficientrecovery equipment and most sensitive leak detection, and if theprice of HFC-134a were high enough to be an effective incentivein repairing leaky systems prior to recharge and high enough toreward auto disassembly enterprises for recovery and recycle. Inthe United States and other countries with untrained and do-it-yourself (DIY) repair of vehicle air conditioners, HFC-134aemissions could be much reduced if refrigerants were sold onlyto certified technicians.

Furthermore, the carbon footprint of mobile A/Cs can befurther reduced by the rapid transition to low-GWP refrigerants

and high energy efficiency using the technology already identi-fied and demonstrated by the mobile A/C industry–governmentpartnerships and by incentivizing further innovation.

In the United States, certified technicians using leakdetectors and recycle/recovery equipment service 90% ofthe fleet of vehicles with the same amount of refrigerantused by DIY car owners to service 10% of the vehicle fleet.Lack of technician training is also a contributing factor forhigher emissions, especially in cases of contamination ofvehicle A/C systems with the wrong refrigerant, failure toidentify and repair leaks, and overcharging of systems. In theEC, HFC-134a emissions could be significantly reduced iftechnicians were required to use the latest recovery/recycle/recharge equipment. In all countries, ozone-depleting andgreenhouse gas refrigerants could be collected and destroyedand the transition to refrigerants with low GWP and highenergy efficiency could be accelerated.

The success of the Montreal Protocol proves that globalcooperation can work, that there is synergy in jointly protectingthe ozone layer and climate, that government–industry coopera-tion can complement conventional regulations, and that globaleconomies of scale in new technology can make environmentalprotection more affordable than ever (Kauffman, 1997; Norman,et al., 2008). The challenge is to continue using the best availablescience, to involve the wider environmental community in pur-suing energy efficiency and health co-benefits, and to becomingmore agile in taking fast action.

Looking to the Future: The Next 25 years ofthe Montreal Protocol

HFC phase-down: Will the Montreal Protocolcomplement the Kyoto Protocol?

HFCs are almost exclusively used as alternatives to ODS, butare no longer needed in many applications. A phase-down ofHFCs would produce an immediate benefit for climate protec-tion due to their high GWPs and short atmospheric lifetimes. TheKyoto Protocol controls the emissions of HFCs, but theMontrealProtocol would control the production and consumption.

N2O, n-propyl bromide and beyond: Will theMontreal Protocol control neglected ODSs?

N2O is the largest identified anthropogenic threat to thestratospheric ozone layer and it is also a climate greenhousegas. n-Propyl bromide (nPb) and RC-316c (1,2-dichloro-1,2,3,3,4,4-hexafluorocyclobutane, CAS 356-18-3) are ODSsolvents with unknown market potential not controlled by theMontreal Protocol. The Montreal Protocol could be amended tocontrol known ODSs listed by name with appropriate phase-down schedules, and to control unknown ODSs listed by chemi-cal description and a preemptive control schedule (say, cappingproduction and consumption at 100 kg). This would allowresearch quantities but require an adjustment to the protocolwhen commercialization was contemplated.


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

HCFC phase-out: Faster and with exemption ofHCFC-123 for building chillers?

The phase-out of HCFC is currently scheduled to reduceHCFCs by 99.5% in developed countries by 2020 and by97.5% by 2030 in developing countries, with 10 more yearseach before 100% phase-out to allow for servicing of existingequipment. Because most HCFCs have high GWPs, it is likelythat 2020 and 2030 dates will be moved forward.

The intriguing exception to an HCFC phase-out is that there islittle, if any, environmental merit in phase-out of HCFC-123 foruse in building air conditioner chillers. HCFC-123 has a lowGWP100yr of 77 and a low ODP of 0.02. HCFC-123 is a liquid atatmospheric temperature and pressure, which allows near-zeroemissions, and it achieves higher energy efficiency than anyother currently available refrigerant. Of course, the GWP andODP are environmentally irrelevant if there are no emissions. Sothe question is whether the Montreal Protocol by Adjustment orglobal Essential Use Exemption will allow for its continued useif no superior technology is commercialized.

New emphasis on treaty synergy and environmentalco-benefits?

The Montreal Protocol incidentally improved the environ-mental performance of products once dependent on ODSs.This occurred through the influence of environment agencieslike U.S. EPA that had authority to approve or disapprove alter-natives and substitutes and through the global network of ozoneoffices and financing organizations that collaborated on technol-ogy choice. A more deliberate and synergistic approach couldcapture co-benefits of energy efficiency, clean air, local sour-cing, and sustainability.

Continued exemption for feedstock and processagents?

Because Feedstock and Process Agent uses are exempt fromMontreal Protocol controls, there has been little incentive tocommercialize chemical pathways to produce the same finalgoods and services avoiding ODSs or to commercialize alter-natives and substitutes for the products made with ODS. Forexample, there is an aqueous alternative to the manufacture ofballistic armor currently manufactured using CFC-113 as aprocess agent and there are many alternatives to products madewith polytetrafluoroethylene (PTFE, commonly known asTeflon). HCFC-22 feedstocks are not significantly emitted inthe manufacture of PTFE, but HFC-23 (GWP100yr ¼14,800) isemitted as an unwanted by-product of HCFC-22 production if itis not captured and destroyed.

What does the future hold for mobile airconditioning?

With the exception of German companies, HFO-1234yf is theglobal industry choice as a replacement for HFC-134a and willbe the choice for German vehicles for the immediate future if theEC enforces its regulation. The questions are: (1) Will HFO-

1234yf be implemented on the same schedule in developing anddeveloped countries? (2) Will CO2 vehicle A/C be offered intemperate climates where energy efficiency and fuel costs arelow priority? (3) Will fundamental changes in vehicle design(electric, fuel cell, and hybrid) allow more toxic, flammable, orhigh-pressure refrigerants to be safely contained in hermiticsystems?

Will environmental, health, and safety authorities stoptrade in counterfeit and controlled refrigerants andDIY service?

The life-cycle benefits of environmentally superior refriger-ants are diminished in systems that are recharged with obsoletelow-cost refrigerants. The illegal trade in ODS refrigerants jeo-pardizes the success of stratospheric ozone protection. The useof counterfeit refrigerants, often containing toxic and explosiveingredients, jeopardizes health and safety and the profitability ofrecycling when contamination prevents reuse. The solutionrequires coordinated actions of customs and environmentalauthorities, chemical suppliers and distributors, waste recovery,recycle and destruction enterprises, and others.

Will chemists and engineers continue the pace oftechnical progress?

If the past is prelude to the future, technical progress willcontinue on refrigeration and air conditioning. The near futureincludes new refrigerants and refrigerant blends, as well as moreefficient heat exchangers and system controls. The more distantfuture includes new compressor configurations, better seals, oil-free designs, magnetic bearings, and high-pressure containment.The far future is anyone’s guess.

Acknowledgment

The authors acknowledge significant contributions from theircolleagues at the Institute for Governance and SustainableDevelopment: Durwood Zaelke, Dennis Clare, DanielleGrabiel, and Xiaopu Sun; from scientist David Fahey andscience writer Lani Sinclair; from automotive experts JohnCabaniss, Paul DeGuiseppi, Elvis Hoffpauir, John Rugh, andJim Taylor; and Montreal Protocol authorities GilbertBankobeza and Megumi Seki.

ReferencesHarvard University Environmental Science and Public Policy Archives (ESPPA)

has large collections of photographs, personal notes, and previously confi-dential information such as records of government negotiating positions andcorporate strategy donated by Stephen O. Andersen, K. Madhava Sarma, andEdward A. Parson. Additional donations are welcome. http://hcl.harvard.edu/libraries/lamont/collections/environment.

American National Standards Institute (ANSI) and American Society of Heating,Refrigerating, and Air-Conditioning Engineers (ASHRAE). 2007. ASHRAEStandard: Designation and Safety Classification of Refrigerants. ANSI/ASHRAE Addendum ak to ANSI/ASHRAE Standard 34-2007. https://www.ashrae.org/File%20Library/docLib/Public/20090224_ad342007x_y_aa_ab_ac_ad_ae.pdf (accessed May 1, 2013).


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

American National Standards Institute/American Society of Heating, Refrigerating,and Air-Conditioning Engineers (ANSI/ASHRAE). 2010. ASHRAE Standard:Designation and Safety Classification of Refrigerants. ANSI/ASHRAEAddendum ak to ANSI/ASHRAE Standard 34-2007. https://www.ashrae.org/.../docLib/.../20100309_34_2007_ak_final.pdf (accessed May 1, 2013).

Andersen, S.O. 1999.HFC and PFC Task Force of the Technology and EconomicAssessment Panel, Montreal Protocol Ozone Secretariat, Nairobi Kenya:UNEP.

Andersen, S.O., and E.T. Morehouse. 1997. The ozone challenge: Industry andgovernment learned to work together to protect the environment. ASHRAE J.39(9): 29–31. bookstore.ashrae.biz/journal/download.php?file=OzoneChallenge.pdf (accessed December 31, 2012).

Andersen, S.O., and K.M. Sarma. 2002. Protecting the Ozone Layer: The UnitedNations History. London, UK: Earthscan Press (official publication of theUnited Nations Environment Programme).

Andersen, S.O., K.M. Sarma, and K.N. Taddonio. 2007. Technology Transfer forthe Ozone Layer: Lessons for Climate Change. London, UK: Earthscan Press(official publication of the Global Environment Facility and the UnitedNations Environment Programme).

Andersen, S.O., and D. Zaelke. 2003. Daimler-Chrysler: CO2, the champagne ofnatural refrigerants. In Industry Genius: Inventions and People Protecting theClimate and Fragile Ozone Layer, 53–69. Sheffield, UK: Greenleaf.

Andersen, S.O., G.J.M. Velders and P. Canan. 2007. How Science GuidesIndustry Choice of Alternatives to Ozone-Depleting Substances,” TwentyYears of Ozone Decline: Proceedings of the Symposium for the 20thAnniversary of the Montreal Protocol. New York, NY: Springer Science.

Anonymous. 1933. First air-conditioned auto. Popular Science Monthly. http://books.google.com/books?id=7CcDAAAAMBAJ&pg=PA30&dq=Popular+Science+1933+plane+%22Popular+Science%22&hl=en&ei=QeBUTc_hNsH-8AaqrZyPBw&sa=X&oi=book_result&ct=result&resnum=2&ved=0CDQQ6AEwAQ#v= onepage&q=Popular%20Science%201933%20plane%20%22Popular%20Science%22&f=true

Arctic Monitoring and Assessment Programme (AMAP). 2011. Snow, Water, Iceand Permafrost in the Arctic. Oslo, Norway: AMAP Secretariat.

Atkinson, W. 1989. A look at the future with HFC-134a. ACtion Magazine.December: 3.

Atkinson, W. 2008. From Montreal to Kyoto: Two Decades of Change in theMobile A/C Industry. Lansdale, PA: Mobile Air Conditioning Society.

Ayala, M., H. Strid, U. Jacobsson, and P.G. Soderberg. 2007. Expression andapoptosis in the lens after ultraviolet radiation exposure. Invest. Ophthalmol.Vis. Sci. 48:4187–91. doi:10.1167/iovs.06-0660

Benedick, R. 1998. Ozone Diplomacy: New Directions in Safeguarding thePlanet, enlarged edition. Cambridge, MA: Harvard University Press.

Bhatti, M.S. 1998. Global Warming Impact of Automotive Air ConditioningSystems. Paper no. 982929. Society of Automotive Engineers, VIIInternational Mobility Technology Conference and Exhibition, November 9–11.

Bhatti, M.S. 1999. Evolution of automotive air conditioning: Riding in comfort.ASHRAE Journal September:44–50. doi:10.4271/1999-01-0870

Billings, J.S. 1893. Ventilating and heating. In Engineering Record (Report ofOfficers of the Navy on Ventilating and Cooling Executive Mansion), Vol. 8.Washington, DC: U.S. Government Printing Office. http://archive.org/stream/ventilationheati00billuoft/ventilationheati00billuoft_djvu.txt

Bodinus, W.S. 1999. The rise and fall of carbon dioxide systems. ASHRAE J.:37–42.

Bond T.C., S.J. Doherty, D.W. Fahey, P.M. Forster, T. Berntsen, B.J. DeAngelo,M.G. Flanner, S. Ghan, B. Karcher, D. Koch, S. Kinne, Y. Kondo, P.K. Huinn,M.C. Sarofim, M. G. Schultz, M. Sculz, C. Venkataraman, H. Zhang, S.Zhang, N. Belouin, S.K. Guttikunda, P.K. Hopke, M.Z. Jacobson, J.W.Kaiser, Z. Klimont, U. Lohmann, J.P. Schwarz, D. Shindell, T. Storelvmo,S.G. Waren, and C.S. Zender. 2013. Bounding the role of black carbon in theclimate system: A scientific assessment, J. Geophys. Res. Atmospheres.doi:10.1002/jgrd.50171

Boutonnet, J.C., P. Bingham, D. Calamari, C. deRooij, J. Franklin, T. Kawano,J.M. Libre, A. McCulloch, G. Malinverno, and J.M. Odom. 1999.Environmental risk assessment of trifluoroacetic acid. Hum. Ecol. RiskAssess. Int. J. 5(1): 59–124. doi:10.1080/10807039991289644

Brodeur, P. 1986. Annals of chemistry. The New Yorker. http://www.newyorker.com/archive/1975/04/07/1975_04_07_047_TNY_CARDS_000311657(accessed December 31, 2012).

Brysse, K. 2009. Oral History Transcript—Dr. Joseph Farman. Niels Bohr Library& Archives, American Institute of Physics, College Park, MD. http://www.aip.org/history/ohilist/33642.html (accessed December 31, 2013).

Cagin, S., and P. Dray. 1993. Between Earth and Sky: How CFCs Changed ourWorld and Endangered the Ozone Layer. New York, NY: Pantheon Books.

Caldwell, M.M. 1971. Solar UV irradiation and the growth and development ofhigher plants. In Photophysiology, Current Topics in Photobiology andPhotochemistr, Vol. VI. ed. A.C. Giese. New York, NY: Academic Press.

Caldwell, M.M., J.F. Bornman, C.L. Ballaré, S.D. Flint, and G. Kulandaivelu.2007. Terrestrial ecosystems, increased solar ultraviolet radiation, and inter-actions with other climate change factors. Photochem. Photobiol. Sci., 6:131–77. doi:10.1039/b700019g

Caldwell, M.M., L.B. Camp, C.W. Warner, and S.D. Flint. 1986. Action spectraand their key role in assessing biological consequences of solar UV-B radia-tion change. In Stratospheric Ozone Reduction Solar Ultraviolet Radiationand Plant Life, ed. R.C. Worrest and M.M. Caldwell, 87–111. Berlin,Germany: Springer.

California Air Resources Board (CARB). 2012. LEV III GreenhouseGasNon-TestCycle Provisions Technical Support Document. Sacramento, CA. http://www.arb.ca.gov/regact/2012/leviiighg2012/levappr.pdf (accessed March 12, 2013).

Calm, J. M. 2012. Refrigerant Transitions. . .Again, Moving TowardsSustainability. Proceedings of the ASHRAE-NIST RefrigerantsConference, Gaithersburg, MD, October 29–30.

Chaney, L., K. Thundiyil, S. O. Andersen, S. Chidambaram, and Y.P. Abbi. 2007.India Fuel Savings and Emission Reductions from Next-Generation MobileAir Conditioning Technology in India. Golden, CO: U.S. Department ofEnergy National Renewable Energy Laboratory.

Chang Y.M., J.H. Barrett, D.T. Bishop, B.K. Armstrong, V. Bataille, W. Bergman,M. Berwick, P.M. Bracci, J.M. Elwood, M.S. Ernstoff, R.P. Gallagher, A.C.Green, N.A. Gruis, E.A. Holly, C. Ingvar, P.A. Kanetsky, M.R. Karagas, T.K.Lee, L. LeMarchand, R.M.Mackie, H. Olsson, A. Osterlind, T.R. Rebbeck, P.Sasieni, V. Siskind, A.J. Swerdlow, L. Titus- Ernstoff, M.S. Zens, and J.A.Newton-Bishop. 2009. Sun exposure and melanoma risk at different lati-tudes: a pooled analysis of 5700 cases and 7216 controls. Int. J. Epidemiol.38:814–30. doi:10.1093/ije/dyp166

Chapman, S. 1931. Some phenomena of the upper atmosphere. Proc. R. Soc.London Ser. A 132(820): 353–374. doi:10.1098/rspa.1931.0105. http://www.jstor.org/stable/95664 (accessed December 31, 2012).

Chubachi, S. 1984. Preliminary Result of Ozone Observations at Syoma Stationfrom February 1982 to January 1983.Memoirs of National Institute of PolarResearch Special Issue No. 34, Proceedings of the Sixth Symposium on PolarMeteorology and Glaciology. http://ci.nii.ac.jp/vol_issue/nels/AA00733561/ISS0000026297_ja.html (accessed December 31, 2012).

Consumer Goods Forum. 2012. Better Lives Through Better Business. http://www.theconsumergoodsforum.com/PDF/CGF_Corporate_Brochure.pdf(accessed May 1, 2013).

Cook, E. 1996. Ozone Protection in the United States: Elements of Success.Washington, DC: World Resources Institute.

Cornú, M. A. 1879. Sur la Limite Ultra-Violette du Spectre Solaire. Proc.R. Society London 29:47–55. doi:10.1098/rspl.1879.0011

Crutzen, P. J. 1970. The influence of nitrogen oxides on the atmospheric ozonecontent. Q. J. R. Meteorol. Society 96(408): 320–325. doi:10.1002/qj.49709640815

Crutzen, P. J. 1972. SST’s: A threat to the earth’s ozone shield.Ambio 1(2): 41–51.Daimler. 2012. New findings concerning the risks of the new R1234yf refriger-

ant: Mercedes-Benz wishes to continue using the tried-and-tested R134arefrigerant in passenger cars. Press release. September 25, 2012. http://media.daimler.com/deeplink?cci=2232953 (accessed December 31, 2012).

DeCanio, S.J., and K.N. Lee. 1991. Doingwell by doing good: Technology transferto protect the ozone. Policy Stud. J. 19:137–148. doi:10.1111/j.1541-0072

Damian D.L., G.M. Halliday, C.A. Taylor, and R.S. Barnetson. 1998. Ultravioletradiation induced suppression of Mantoux reactions in humans. J. Invest.Dermatol. 110:824–27. doi:10.1046/j.1523-1747.1998.00176.x


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

de Gruijl, F.R., J. Longstreth, M. Norval, A.P. Cullen, H. Slaper, M.L. Kripke, Y.Takizawa, and J.C. van der Leun. 2003. Health effects from stratosphericozone depletion and interactions with climate change. Photochem. Photobiol.Sci. 2:16–28. doi:10.1039/b211156j

Dobson, G.M.B. 1968. Forty years’ research on atmospheric ozone at Oxford: Ahistory. Appl. Optics 7(3):387–405. doi:10.1364/AO.7.000387

Dobson, G.M.B., and D.N. Harrison. 1926. Measurements of the amount of ozonein the earth’s atmosphere and its relation to other geophysical conditions. Proc.R. Society London Ser. A 110(756): 660–93. doi:10.1098/rspa.1926.0040

Donaldson, B., and B. Nagengast. 1994. Heat and Cold: Mastering the GreatIndoors: A Selective History ASHRAE Code 40303. Atlanta, GA: AmericanSociety of Heating, Refrigerating and Air-Conditioning Engineers, Inc.

Doniger, D. 1988. Politics of the ozone layer. Issues Sci. Technol. 4(3): 86–92.Dubey, M.K., G.P. Smith, W.S. Hartley, D.E. Kinnison, and P.S. Connell. 1997.

Rate parameter uncertainty effects in assessing stratospheric ozone depletionby supersonic aviation. Geophys. Res. Lett. 24(22): 2737–40. doi:10.1029/97GL02859

Dudek, D.J., A.M. Leblanc, and K. Sewall. 1990. Cutting the cost of environ-mental policy: Lessons from business response to CFC regulation. Ambio 19(6/7): 324–28.

European Commission. 2012. Declaration by the European Commission regardingPoint 9 of the agenda of the 31st meeting of the ‘Technical Committee—Motorvehicles’ (TCMV): State of Play of the EU Mobile Air-Conditioning directive(2006/40/EC). http://ec.europa.eu/enterprise/sectors/automotive/files/environment/mac/note-macs-december-2012_en.pdf (accessed May 1, 2013).

European Commission. 2013a. Automotive Mobile Air-Conditioning Systems(MACs): The European Directive on Mobile Air-Conditioning Systems(MACs) Aims at Reducing Emissions of Specific Fluorinated GreenhouseGases in the Air-Conditioning Systems Fitted to Passenger Cars (Vehicles ofCategory M1) and Light Commercial Vehicles (Category N1, Class 1). http://ec.europa.eu/enterprise/sectors/automotive/environment/macs/index_en.htm. (accessed March 4, 2013).

European Commission. 2013b. Implementation of Directive 2006/40/EC—Questions and Answers. Brussels. http://ec.europa.eu/enterprise/sectors/automotive/files/environment/mac/q-and-a_en.pdf (accessed March 4, 2013).

European Commission Community Research and Development InformationService. 1997. Refrigeration and Automotive Climate Systems UnderEnvironmental Aspects. http://cordis.europa.eu/search/index.cfm?fuseaction=proj.document&PJ_LANG=EN&PJ_RCN=710487 (accessedDecember 31, 2012).

European Community Enterprise and Industry Directorate-General (ECEID-G).2012. Note to the Attention of the Members of the Technical Committee onMotor Vehicle. http://ec.europa.eu/enterprise/sectors/automotive/files/environment/mac/note-macs-april-2012_en.pdf (accessed December 31, 2012).

Fahey,W.D., andM.I. Hegglin (coordinating lead authors). 2011. Twenty Questionsand Answers About the Ozone Layer: 2010. Scientific Assessment of OzoneDepletion. Reprinted from World Meteorological Organization. 2011.Scientific Assessment of Ozone Depletion: 2010. Global Ozone Research andMonitoring Project Report No. 52. Geneva, Switzerland: WorldMeteorological Organization.

Farman, J.S., B.G. Gardiner, and J.D. Shanklin. 1985. Large losses of total ozonein antarctic reveal seasonal ClOx/NOx interaction. Nature 315:207–10.doi:10.1038/315207a0

Fischer, S.K., P.J. Hughes, P.D. Fairchild, C.L. Kusik, J.T. Dieckmann, E.M.McMahon, and N. Hobday. 1991. Energy and Global Warming Impacts ofCFC Alternative Technologies. Washington, DC: U.S. EPA.

Fisk D. 1934. Exploring the Upper Atmosphere. Oxford, UK: Oxford UniversityPress.

Forster P., V. Ramaswamy, P. Artaxo, T. Berntsen, R. Betts, D. W. Fahey, J.Haywood, J. Lean, D. C. Lowe, G. Myhre, J. Nganga, R. Prinn, G. Raga,M. Schulz, and R. Van Dorland. 2007. Changes in atmospheric constituentsand in radiative forcing. In Climate Change: The Physical Science Basis.Contribution of Working Group I to the Fourth Assessment Report of theIntergovernmental Panel on Climate Change. Cambridge, UK CambridgeUniversity Press.

Franklin, B. 1758. Cooling by Evaporation. Letter to John Lining. London, June17, 1758. http://www.waughfamily.ca/Montgomery/benfranklin1758.htm

Gaved, A. 2010. General Motors to Use New Car Refrigerant from 2013. http://www.racplus.com/news/refrigeration/general-motors-to-use-new-car-refrigerant-from-2013/8603813.article (accessed December 31, 2012).

Gibson, G.V., and R.W. Smilor. 1992. Technology Transfer in Consortia andStrategic Alliances. Lanham, MD: Rowman & Littlefield.

Gladstone, J. 1998. John Gorrie, The visionary. ASHRAE J. December: 29–35.Glas, J. P. 1989. Protecting the ozone layer: A perspective from industry. In

Technology and Environment, 137–155. Washington, DC: NationalAcademy Press http://www.nap.edu/openbook.php?record_id=1407&page=137 (accessed December 31, 2012).

Gale A. J. 2006. PHMSA Interpretation #06-0097, PHMSA Response Letter 11July, 2006. http://www.phmsa.dot.gov/portal/site/PHMSA/menuitem.ebd-c7a8a7e39f2e55cf2031050248a0c/?vgnextoid=381ac0515d544110VgnVCM1000009ed07898RCRD&vgnextchannel=aa8cd3c1af814110VgnVCM1000009ed07898RCRD&vgnextfmt=print.

GM. 2010. GM First to Market Greenhouse Gas-Friendly Air ConditioningRefrigerant in U.S. Inside News Forum. http://www.gminsidenews.com/forums/f12/gm-first-market-greenhouse-gas-friendly-air-conditioning-refrigerant-u-s-93968/ (accessed December 31, 2012).

Götz, F.W.P. 1931. Das Atmospharische Ozon. Ergebnisse der KomschenPhysik1:180–235.

Götz, F.W.P., A.R. Meetham, and G.M.B. Dobson. 1934. The vertical distributionof ozone in the atmosphere. Proc. R. Society London Ser. A 145(855):416–46. doi:10.1098/rspa.1934.0109. http://www.jstor.org/stable/2935512(accessed December 31, 2012).

Hammer, H., I. Lazaridis, S. Morgenstern, J. Wertenbach, and S. Wöhrl. 2012.R1234yf—A new, safe and environmentally friendly refrigerant for mobile airconditioning.www.rivoiragas.it/wp-content/uploads/pdf/Presentazione%20European%20Automotive%20AC%20Convention.pdf (accessed December 31,2012).

Harrison, H. 1970. Stratospheric ozone with added water vapour: Influence ofhigh-altitude aircraft. Science 170(3959): 734–36. doi:10.1126/science.170.3959.734

Harry H.W. 1999. The First Century of Air Conditioning. ASHRAECode 90415.Atlanta, GA: American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.

Hartley, W.N. 1880. On the probable absorption of the solar ray by atmosphericozone. Chemical News 268 (November 26).

Henne, A.L., and C.J. Fox. 1951. Ionization constants of fluorinated acids. J. Am.Chem. Soc. 73(5): 2323–25. doi:10.1021/ja01149a122

Henne, S., D.E. Shallcross, S. Reimann, P. Xiao, D. Brunner, S. O’Doherty, andB. Buchmann. 2012. Future emissions and atmospheric fate of HFO-1234yffrom mobile air conditioners in Europe. Environ. Sci. Technol. 46(3): 1650–58. doi:10.1021/es2034608

Hidy, G.M., J.R. Brook, J.C. Chow, M.C. Green, R.B. Husar, C. Lee, R.D.Scheffe, A. Swanson, and J.G. Watson. 2009. Remote sensing of particulatepollution from space: Have we reached the promised land?: A critical review.J. Air Waste Manage. Assoc. 59 (10), 1130–39. doi:10.3155/1047-3289.59.10.1130

Hill, R.W., and S. Papasavva. 2005. Life Cycle Analysis Framework; AComparison of HFC-134a, HFC-134a Enhanced, HFC-152a, R744, R744Enhanced, and R290. SAE Technical Paper 2005-01-1511. doi:10.4271/2005-01-1511

Hoff, R.M., and S.A. Christopher. 2009. Remote sensing of particulate pollutionfrom space: Have we reached the promised land? A critical review. J. AirWaste Manage. Assoc. 59(6): 645–75. doi:10.3155/1047-3289.59.6.645

Hoffpauir, E. 2012. Personal communication with author. Mobile AirConditioning Society Worldwide (MACS), Lansdale PA.

Homer. 850 BC. The Iliad and The Odyssey. Reprinted 2007. Blacksburg, VA:Wilder Publications. ISBN-10:1934451460.

Hu, A., Y. Xu, C. Tebaldi, W. M. Washington, and V. Ramanathan 2013.Mitigation of short-lived climate pollutants slows sea-level rise, NatureClimate Change. doi:10.1038/NCLIMATE1869.


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

Institute for Governance & Sustainability. 2013. Primer on Short-Lived ClimatePollutants. Washington, DC: IGSD.

Industrial Hydrocarbons, Inc. 2012. Aerosol Product Storage and Warehousing.www.industrialhydrocarbons.com/storage.htm (accessed December 31, 2012).

Intergovernmental Panel on Climate Change. 2005. Safeguarding the OzoneLayer and the Global Climate System. Cambridge, UK: CambridgeUniversity Press.

Intergovernmental Panel on Climate Change. 2012. Managing the Risks ofExtreme Events and Disasters to Advance Climate Change Adaptation. ASpecial Report of Working Groups I and II of the Intergovernmental Panel onClimate Change. http://www.ipcc-wg2.gov/SREX/images/uploads/SREX-All_FINAL.pdf (accessed December 31, 2012).

International Energy Agency. 2012. World Energy Outlook 2012. Paris, France:International Energy Agency.

J & E Hall International. 2012. History: More Than 200 Years of Progress andAchievement. http://www.jehall.co.uk/about/history.jsp (accessed December31, 2012).

Johnson, V.H. 2002. Fuel Used for Vehicle Air Conditioning: A State-by-StateThermal Comfort-Based Approach. SAE Technical Series Paper 2002-01-1957. doi:10.4271/2002-01-1957

Johnston, H.S. 1971. Reduction of stratospheric ozone by nitrogen oxide cata-lysts from supersonic transport exhaust. Science 173(3996): 517–22.doi:10.1126/science.173.3996.517

Kanter, D., D.L. Mauzerall, A.R. Ravishankara, J.S. Daniel, R.W. Portmann, P.M.Grabiel, W.R. Moomaw, and J.N. Galloway. 2013. A post-Kyoto partner:Considering the stratospheric ozone regime as a tool to manage nitrousoxide. Proc. Natl. Acad. Sci. USA. doi:10.1073/pnas.12222231110

Kauffman, G.B. 1989. Midgley: Saint or serpent? Chemtech Magazine 19(12):717–25.

Kauffman, J.M. 1997. Domestic and international linkages in global environ-mental politics: A case-study of the Montreal Protocol. InInternationalization of Environmental Protection, ed. M.A. Schreurs and E.Economy. Cambridge, UK: Cambridge University Press.

Khattatov, V. 2002. How common concern for the environment led to cooperationin space. In Protecting the Ozone Layer: The United Nations History, ed. S.O.Andersen and K.M. Sarma. London, UK: Earthscan Press (official publica-tion of the United Nations Environment Programme).

Kripke, M.L. 1974. Antigenicity of murine skin tumors induced by ultravioletlight. J. Natl. Cancer Inst. 53:1333–36.

Laszlo, P. 2001. Salt: Grain of Life. Translated from the 1998 original by MaryBeth Mader. New York, NY: Columbia University Press.

Le Prestre, P.G., J.D. Reid, and E.T.Morehouse, Jr., eds. 1998.Protecting the OzoneLayer: Lessons, Models and Prospects. Boston, MA: Kluwer Academic.

Leeds, A.R. 1879. Lines of discovery in the history of ozone, with an index of itsliterature, and an appendix upon the literature of peroxide of hydrogen. Ann.NY Acad. Sci. 1(1): 363–91. doi:10.1111/j.1749-6632.1879.tb55134.x

Link, A.N., and J.T. Scott. 2001. Public/private partnerships: Stimulating com-petition in a dynamic market. Int. J. Ind. Organization 19(5): 763–94.doi:10.1016/S0167-7187

Lorentzen, G., and J. Pettersen. 1993. A new, efficient and environmentallybenign system for car air-conditioning. Int. J. Refrigeration 16(1): 4–12.doi:10.1016/0140-7007(93)90014-Y

Lovelock, J.E. 1971. Atmospheric fluorine compounds as indication of air move-ments. Nature 230(5293): 379. doi:10.1038/230379a0

Lovelock, J.E., R.J. Maggs, and R.J. Wade. 1973. Halogenated hydrocarbons inand over the Atlantic.Nature 241:194–96. doi:10.1038/241194a0 (as cited inKowalok, M.E. 1993. Common threads: Research lessons from acid rain,ozone depletion, and global warming. Environment 35(6):12–38.doi:10.1080/00139157.1993.9929107

Luderer G., V. Bosetti, M. Jakob,M. Leimbach, J. C. Steckel, H.Waisman, and O.Edenhofer. 2012. The economics of decarbonizing the energy system:Results and insights from the RECIPE model intercomparison. ClimaticChange 114(1): 9–37. doi:10.1007/s10584-011-0105-x

Luecken, D.J., R.L. Waterland, S. Papasavva, K.N. Taddonio, W.T. Hutzell, J.P.Rugh, and S.O. Andersen. 2010. Ozone and TFA impacts in north americafrom degradation of 2,3,3,3-tetrafluoropropene (HFO-1234yf), a potential

greenhouse gas replacement. Environ. Sci. Technol. 44(1): 343–48.doi:10.1021/es902481f

Luedecke, C. 2004. The First International Polar Year (1882–83): A big scienceexperiment with small science equipment. Proc. Int Commission on Historyof Meteorology. http://www.meteohistory.org/2004proceedings1.1/pdfs/06luedecke.pdf (accessed May 1, 2013).

McCarthy, R. 1972. DuPont business correspondence.McCulloch, A. 1999. CFC and halon replacements in the environment.

J. Fluorine Chem. 100(1–2): 163–73. doi:10.1016/S0022-1139(99)00198-0McDonald, J.E. 1971. Relationship of skin cancer incidence to thickness of ozone

layer. Statement submitted to hearings before the House Subcommittee onTransportation Appropriations (Mar 2, 1971). Cong. Rec. 117:7252.

McNeil, M.A., V.E. Letschert, and S. de la Rue du Can. 2008.Global Potential ofEnergy Efficiency Standards and Labeling Programs. Berkeley, CA:Lawrence Berkeley National Laboratory Environmental EnergyTechnologies Division.

Meinshausen, M., N. Meinshausen, W. Hare, S.C.B. Raper, K. Frieler, R. Knutti,D.J. Frame, andM.R. Allen 2009. Greenhouse-gas emission targets for limitingglobal warming to 2�C. Nature 458:1158–62. doi:10.1038/nature08017

Mercedes-Benz. 2012. Re: Part 573 Defect Information Report. Letter fromMercedes-Benz to the U.S. National Highway Traffic Safety AdministrationDivision, Washington, DC, dated 28 September 2012. http://www-odi.nhtsa.dot.gov/acms/cs/jaxrs/download/doc/UCM427727/RCDNN-12V478-4113.pdf (accessed December 31, 2012).

Metz, B., L. Kuijpers, S. Solomon, S.O. Andersen, O. Davidson, J. Pons, D. deJager, T. Kestin, M. Manning, and L. Meyer. 2005. Safeguarding theStratospheric Ozone Layer and the Global Climate: Issues Relating toHydrofluorocarbons and Perfluorocarbons. Cambridge, UK: CambridgeUniversity Press.

Meyer L.M., X. Dong, A. Wegener, and P. Soderberg. 2008. Dose dependentcataractogenesis and maximum tolerable dose (MTD. (2.3:16)) for UVR 300nm- induced cataract in C57BL/6J mice. Exp. Eye Res. 86:282–89.doi:10.1016/j.exer.2007.10.019

Miller, A., and I. Mintzer 1986. The Sky Is the Limit: Strategies for Protecting theOzone Layer. Washington, DC: World Resources Institute.

Minnesota Pollution Control Agency. 2011. Climate Change: Mobile AirConditioners. http://www.pca.state.mn.us/index.php/topics/climate-change/regulatory-initiatives-programs-and-policies/climate-change-mobile-air-conditioners.html?menuid=&redirect=1 (accessed December 31, 2012).

Minnesota Session Laws. 2008. Mobile Air Conditioner Leakage Rates;Disclosure. 2008 c 296 art 1 s 23. https://www.revisor.leg.state.mn.us/statutes/?id=216H&view=chapter#stat.216H.12.

Mobile Air Conditioning Society 2012. The Bumpy Road to R-1234yf. ACtionNovember/December. http://www.nxtbook.com/nxtbooks/macs/action_20121112/#/0.

Molina, M., and F.S. Rowland 1974. Stratospheric sink for chlorofluoro-methanes: chlorine atom-catalyzed destruction of ozone. Nature 249(5460):810–12. doi:10.1038/249810a0

Molina, M., D. Zaelke, K.M. Sarma, S.O. Andersen, V. Ramanathan, and D.Kaniaru 2009. Reducing abrupt climate change risk using the MontrealProtocol and other regulatory actions to complement cuts in CO2 emissions,Proc. Natl. Acad. Sci. USA 106(49): 20616–21. doi:10.1073/pnas.0902568106

Montreal Protocol Technology and Economic Assessment Panel. 2009. TaskForce Decision XX/8 Report: Assessment of Alternatives to HCFCs andHFCs and Update of the TEAP 2005 Supplement Report Data. http://ozone.unep.org/teap/Reports/TEAP_Reports/teap-may-2009-decisionXX-8-task-force-report.pdf (accessed December 31, 2012).

Montreal Protocol on Substances that Deplete the Ozone Layer. 2002. DecisionXIV/10 UNEP/Ozl.Pro.14/9, Fourteenth MOP to the Montreal Protocol,Rome, Italy, 25–29 November.

Morgenstern, O., P. Braesicke, M.M. Hurwitz, F.M. O’Connor, A.C. Bushell,C.E. Johnson, and J.A. Pyle. 2008. The world avoided by the MontrealProtocol. Geophys. Res. Lett. 35(L16811): 5. doi:10.1029/2008GL034590

Nagengast, B. 1997. History of sealed refrigeration systems, ASHRAE J. January:S44–52.

Nagengast, B. 1988. A historical look at CFC refrigerants, ASHRAE J. XX:37–39.


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

Nagengast, B. 1999. Comfort from a block of ice: A history of comfort coolingusing ice. ASHRAE J. 41(2).

Narbutt, J., A. Lesiak, M. Skibinska, A. Wozniacka, H. van Loveren, A. Sysa-Jedrzejowska, I. Lewy-Trenda, A. Omulecka, and M. Norval. 2005.Suppression of contact hypersensitivity after repeated exposures of humansto low doses of solar simulated radiation. Photochem. Photobiol. Sci. 4:517–22. doi:10.1039/b503166d

National Aeronautics and Space Administration. 2009. New Simulation ShowsConsequences of a World Without Earth’s Natural Sunscreen.” http://www.nasa.gov/topics/earth/features/world_avoided.html (accessed May 1, 2013).

National Academy of Engineers. 2013. Greatest Engineering Achievements ofthe 20th Century: Air Conditioning and Refrigeration History. http://www.greatachievements.org/?id=2958 (accessed February 23, 2013).

National Aeronautics and Space Administration, Federal AviationAdministration, U.S. National Oceanic and Atmospheric Administration,United Nations Environment Programme, World MeteorologicalOrganization, Commission of the European Communities, andBundesministerium für Forschung und Technologie. 1985. AtmosphericOzone 1985: Assessment of our Understanding of the ProcessesControlling Its Present Distribution and Change. Washington, DC:National Aeronautics and Space Administration.

National Aeronautics and Space Administration, Goddard Space Flight Center.1996. The Airborne Antarctic Ozone Experiment. http://hyperion.gsfc.nasa.gov/Analysis/aircraft/aaoe.html (accessed December 31, 2012).

National Aeronautics and Space Administration, Jet Propulsion Laboratory,USA. 2000. Ozone Milestones. http://atmos.jpl.nasa.gov/milestones.htm(accessed December 31, 2012).

National Oceanic and Atmospheric Administration (NASA), Federal AviationAdministration (FAA), World Meteorological Organization (WMO), andUnited Nations Environment Programme (UNEP) 1988. Report of theInternational Ozone Trends Panel 1988 Washington DC: NationalAeronautics and Space Administration.

National Oceanic and Atmospheric Administration, National Aeronautics andSpace Administration, United Nations Environment Programme, WorldMeteorological Organization, and European Commission. 2011. ScientificAssessment of Ozone Depletion: 2010. http://ozone.unep.org/Assessment_Panels/SAP/Scientific_Assessment_2010/01-Contents_Preface.pdf(accessed December 31, 2012).

National Research Council. 1975. Environmental Impact of Stratospheric Flight.Washington, DC: National Academy of Sciences.

National Research Council. 1976.Halocarbons: Effects on Stratospheric Ozone.Washington, DC: National Academy of Sciences.

National Research Council. 1979. Protection against Depletion of StratosphericOzone by Chlorofluorocarbons. Washington, DC: National Academy ofSciences.

National Research Council. 1982. Causes and Effects of Stratospheric OzoneReduction: An Update. Washington, DC: National Academy of Sciences.

National Research Council. 1983. Causes and Effects of Changes inStratospheric Ozone: Update 1983. Washington, DC: National Academy ofSciences.

Needham, J. 1991. Science and Civilization in China, Volume 4: Physics andPhysical Technology, Part 2, Mechanical Engineering. Cambridge, UK:Cambridge University Press.

Nielsen, O.J., M.S. Javadi, M.P. Sulbaek-Andersen,M.D. Hurley, T.J. Wallington,and R. Singh. 2007. Atmospheric chemistry of CF3CFCH2: Kinetics andmechanisms of gas-phase reactions with Cl atoms, OH radicals, and O3.Chem. Phys. Lett. 439(1–3): 18–22. doi:10.1016/j.cplett.2007.03.053

Newman, P.A., L.D. Oman, A.R. Douglass, E.L. Fleming, S.M. Frith, M.M.Hurwitz, S.R. Kawa, C.H. Jackman, N.A. Krotkov, E.R. Nash, J.E. Nielsen,S. Pawson, R.S. Stolarski, and G.J.M. Velders. 2009. What would have hap-pened to the ozone layer if chlorofluorocarbons (CFCs) had not been regulated?Atmos. Chem. Phys. 9(6): 2113–28. doi:10.5194/acp-9-2113-2009

Norman, C.S., S.J. DeCanio, and L. Fan. 2008. The Montreal Protocol at 20:Ongoing opportunities for integration with climate protection. GlobalEnviron. Change Hum. Policy Dimens. 18(2): 330–40. doi:10.1016/j.gloenvcha.2008.03.003

Norval, M., A.P. Cullen, F.R. de Gruijl, J. Longstreth, Y. Takizawa, R.M. Lucas,F.P. Noonan, and J.C. van der Leun. 2007. The effects on human health fromstratospheric ozone depletion and its interactions with climate change.Photochem. Photobiol. Sci. 6:232–51. doi:10.1039/b700018a

Oreskes, N., and E.M. Conway. 2010. Merchants of Doubt: How a Handful ofScientists Obscured the Truth on Issues from Tobacco Smoke to GlobalWarming. New York, NY: Bloomsbury Press.

Oriowo, O.M., A.P. Cullen, B.R. Chou, and J.G. Sivak. 2001. Action spectrumand recovery for in vitro UV-induced cataract using whole lenses. Invest.Ophthalmol. Vis. Sci. 42:2596–602.

Palmer, M. 1973. William Soltau Davidson: A pioneer of New Zealand estatemanagement. N. Z. J. History 7(2): 148–164.

Papasavva, S., W.R. Hill, and R.O. Brown. 2008. GREEN-MAC-LCCP©: AToolfor Assessing Life Cycle Greenhouse Emissions of Alternative Refrigerants.SAE Technical Series Paper 2008-01-0829. doi:10.4271/2008-01-0828

Papasavva, S., W.R. Hill, and S.O. Andersen. 2010. GREEN-MAC-LCCP©: Atool for assessing the life cycle climate performance of MAC systems.Environ. Sci. Technol. 44(19): 7666–72. doi:10.1021/es100849g

Papasavva1, S., and S.O. Andersen. 2011. GREEN-MAC-LCCP©: Life-CycleClimate Performance Metric for Mobile Air Conditioning TechnologyChoice. Environ. Prog. Sustain. Energy 30(2): 234–47. doi:10.1002/ep.10465

Papasavva, S., and W.R. Moomaw. 1998. Life-cycle global warming impact ofCFCs and CFC-substitutes for refrigeration. J. Ind. Ecol. 1(4): 71–91.doi:10.1162/jiec.1997.1.4.71

Parson, E.A. 2003. Protecting the Ozone Layer: Science and Strategy. New York,NY: Oxford University Press.

Parson, E.A., and O. Greene. 1995. The complex chemistry of the internationalozone agreements. Environment 37(2): 16–20, 35–43. doi:10.1080/00139157.1995.9929219

Pearce, F. 2008.Who really discovered the ozone hole?New Scientist 2674: 46–47.Prather, M.J., M.B. McElroy, and S.C. Wofsy. 1984. Reductions in ozone at high

concentrations of stratospheric halogens. Nature 312:227–31. doi:10.1038/312227a0

Ramanathan, V. 1975. Greenhouse effect due to chlorofluorocarbons: Climaticimplications. Science 190:50–52. doi:10.1126/science.190.4209.50

Ramanathan, V., et al. 1985. Trace gas trends and their potential role in climatechange. J. Geophys. Res. 90(D3): 5547–66. doi:10.1029/JD090iD03p05547

Ramanathan, V., and Y. Xu. 2010. The Copenhagen Accord for Limiting GlobalWarming: Criteria, constraints, and available avenues. Proc. Natl. Acad. Sci.USA 107(18): 8055–62. doi:10.1073/pnas.1002293107

Ravishankara, A.R. 2012. Emerging issues: HFCs and Nitrous Oxide, MontrealProtocol Seminar: Protecting Our Atmosphere, Meeting of the Parties to theMontreal Protocol. Geneva Switzerland, 11 November.

Refrigerants, Naturally! 2012. What We Do. http://www.refrigerantsnaturally.com/about-us/what-we-do.htm (accessed January 3, 2013).

Rivas, M., M.C. Araya, V. Duran, E. Rojas, J. Cortes, and G.M. Calaf. 2009.Ultraviolet light exposure and skin cancer in the city of Arica, Chile. Mol.Med. Rep. 2(4): 567–72. doi:10.3892/mmr_00000138

Rugh, J., V. Hovland, and S.O. Andersen. 2004. Significant Fuel Savings andEmission Reductions by Improving Vehicle Air Conditioning. Presentation atthe 15th Annual Earth Technologies Forum and Mobile Air ConditioningSummit, Washington, DC, April 15.

Rugh, J.P., and R. Farrington. 2008. Vehicle Ancillary Load Reduction ProjectClose-Out Report: An Overview of the Task and a Compilation of theResearch Results, NREL Technical Report. Golden, CO: U.S. Departmentof Energy National Renewable Energy Laboratory.

International. 2004. Cooperative Research Program. SAE Alternate RefrigerantCooperative Research Project Phase I. http://www.sae.org/standardsdev/tsb/cooperative/altsummary-ph1.pdf (accessed December 31, 2012).

SAE International. 2012. SAE International Cooperative Research Project OffersUpdate on R1234yf Refrigerant. Press release, December 14. http://www.sae.org/servlets/pressRoom?OBJECT_TYPE=PressReleases&PAGE=showRelease&RELEASE _ID=1941.

SAE International. 2013. HFC-134a (R-134a) Recovery/Recycle/RechargingEquipment for Mobile Air-Conditioning Systems. http://standards.sae.org/j2788_201301.


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

SAE. 2013a. SAE International CRP1234-4 Analysis of R-1234yf NearsCompletion. http://www.sae.org/servlets/pressRoom?OBJECT_TYPE=PressReleases&PAGE=showRelease&RELEASE_ID=2063 (accessed May2, 2013).

Schneider, S.H., S. Semenov, A. Patwardhan, I. Burton, C.H.D. Magadza, M.Oppenheimer, A.B. Pittock, A. Rahman, J.B. Smith, A. Suarez, and F. Yamin2007. Assessing key vulnerabilities and the risk from climate change. In:Climate Change 2007: Impacts, Adaptation and Vulnerability. Contributionof Working Group II to the Fourth Assessment Report of theIntergovernmental Panel on Climate Change, 779–810. Cambridge, UK:Cambridge University Press.

Schwartz, W. 2001. Emissions of Refrigerant R-134a from Mobile AirConditioning Systems, prepared for the German Federal EnvironmentOffice. http://www.umweltdaten.de/publikationen/fpdf-l/3110.pdf (accessedDecember 31, 2012).

Schwartz, W., and J. Harnisch. 2003. Final Report on Establishing Leakage Ratesof Mobile Air Conditioners, prepared for the European Commission (DGEnvironment). http://ec.europa.eu/clima/policies/eccp/docs/leakage_rates_final_report_en.pdf (accessed December 31, 2012).

Schwarz, W., B. Gschrey, A. Leisewitz, A. Herold, S. Gores, I. Papst, J. Usinger,D. Oppelt, I. Croiset, P.H. Pedersen, D. Colbourne, M. Kauffeld, K. Kaar, andA. Lindborg. 2011. Preparatory Study for a Review of Regulation (EC) No842/2006 on Certain Fluorinated Greenhouse Gases: Final Report. EuropeanCommission. http://ec.europa.eu/clima/policies/f-gas/docs/2011_study_en.pdf (accessed December 31, 2012).

Scientific Assessment Panel. 2010. The 2010 Assessment of the ScientificAssessment Panel. Nairobi, Kenya: Montreal Protocol Ozone Secretariat.

Scott, J.T. 2008. The National Cooperative Research and Production Act. IssuesCompetition Law Policy 2:1297–317 (ABA section of Antitrust Law).

Seidel, S.R. 1996. Keeping cars cool. In Ozone Protection in the United States:Elements of Success, ed. E. Cook. Washington DC: World Resources Institute.

Shindell, D., J.C.I. Kuylenstierna, E. Vignati, R. van Dingenen, M. Amann, Z.Klimont, S.C. Anenberg, et al. 2012. Simultaneously mitigating near-termclimate change and improving human health and food security. Science335:183. doi:10.1126/science.1210026

Singh, A.K., M. Kumar, and Atul Bagai. 2009. Ozone Protection and NationalSecurity—A Military Perspective Toolkit for Defence Forces. Nairobi,Kenya: UNEP.

Siegl, W.O., and T.J. Wallington. 2002. R134a emissions from vehicles. Environ.Sci. Technol. 36(4): 561–66. doi:10.1021/es011108x

Slapper, H., G.J.M. Velders, and J. Matthijsen. 1998. Ozone depletion and skincancer incidence: A source risk approach. J. Hazard. Mater. 61(1–3): 77–84.doi:10.1016/S0304-3894(98)00110-1

Solomon, S., R.R. Garcia, F.S. Rowland, and D.J. Wuebbles. 1986. On thedepletion of Antarctic ozone. Nature 321:755–58. doi:10.1038/321755a0

Solomon, S., D. Qin, M.Manning, Z. Chen,M.Marquis, K.B. Averyt, M. Tignor,and H.L. Miller, 2007. Contribution of Working Group I to the FourthAssessment Report of the Intergovernmental Panel on Climate Change.Cambridge, UK: Cambridge University Press.

Stolarski, R.S. 1999. History of the Study of Atmospheric Ozone. http://hyperion.gsfc.nasa.gov/Personnel/people/Stolarski_Richard_S./history.html.

Strutt, R.J. 1918. Ultra-violet transparency of the lower atmosphere, and itsrelative poverty in ozone. Proc. R. Society London Ser. A 94(660): 260–68.doi:10.1098/rspa.1918.0012

Sullivan, W. 1975. Ozone depletion seen as a war tool. New York Times February28: 20.

Swaminathan T. P. A., and R. M. Lucas 2012. Climate change and health with anemphasis on interactions with ultraviolet radiation: a review. Global ChangeBiology, 18(8):2392–2405. doi:10.1111/j.1365-2486.2012.02706.x

Teramura, A.H., and J.H. Sullivan. 1991. Potential impacts of increased solar UV-B on global plant productivity. In Photobiology, ed. E. Riklis. New York, NY:Plenum Press.

Tevini, M. 1998. Effects of UV-B on plants and terrestrial ecosystems. InProtecting the Ozone Layer: Lessons, Models, and Prospects, ed. P.G. LePrestre, J.D. Reid. and E.T. Morehouse. New York, NY: Springer.

The Online Imperial Club, 2001. Airtemp: Chrysler’s Airy Solution to the Long,Hot Summer. http://www.imperialclub.com/Repair/Air/airtemp.htm (accessedDecember 31, 2012).

U.S. Federal Register. 2008. Protection of the Stratospheric Ozone: Alternativesfor the Motor Vehicle Air Conditioning Sector Under the Significant NewAlternatives Policy (SNAP) Program; Final Rule. 40 CFR Part 82.

U.S. Federal Register. 2011. Protection of Stratospheric Ozone: New Substitutein the Motor Vehicle Air Conditioning Sector Under the Significant NewAlternatives Policy (SNAP) Program; Final Rule. 40 CFR Part 82.

U.S. Federal Register. 2012. Protection of Stratospheric Ozone: Alternative forthe Motor Vehicle Air Conditioning Sector Under the Significant NewAlternatives Policy (SNAP) Program; Final Rule. 40 CFR Part 82.

United Nations. 2012. Resolution adopted by the General Assembly: The FutureWe Want, A/res/66/288. http://www.uncsd2012.org/thefuturewewant.html(accessed May 1, 2013).

United Nations Environment Programme. 1978. Ozone Layer Bulletin. Nairobi,Kenya: UNEP (UN Document number Na 77-5494, January).

United Nations Environment Programme. 1978. UNEP Ozone Layer Bulletin 2.Nairobi, Kenya: UNEP (July).

United Nations Environment Programme. 1979. UNEP Ozone Layer Bulletin 3(Volume II, no. 1). Nairobi, Kenya: UNEP (UN Document number Na 78-4873, January).

United Nations Environment Programme. 1979. UNEP Ozone Layer Bulletin 4(Volume II, no. 2). Nairobi, Kenya: UNEP (July).

United Nations Environment Programme. 1980. UNEP Ozone Layer Bulletin 5.Nairobi, Kenya: UNEP.





United Nations Environment Programme. 1989. Technical Progress onProtecting the Ozone Layer; Report of the Technology Review PanelPursuant to Article (6) of the Montreal Protocol on Substances ThatDeplete the Ozone Layer Under the Auspices of the United NationsEnvironment Program. Nairobi, Kenya: UNEP. ISBN: 9280712470.

United Nations Environment Programme. 1999. The Implications to theMontreal Protocol of the Inclusion of HFCs and PFCs in the KyotoProtocol. Nairobi, Kenya: UNEP.

United Nations Environment Programme. Decision XXII/Anx III: Annex III -2010. Declaration on The Global Transition Away FromHydrochlorofluorocarbons (HCFCs) and Chlorofluorocarbons (CFCs).Nairobi, Kenya: UNEP (UN Document number UNEP/Ozl.Pro.22/9).

United Nations Environment Programme. 2010a.Environmental Effects of OzoneDepletion And Its Interactions With Climate Change: 2010 Assessment.Nairobi, Kenya: UNEP.

United Nations Environment Programme. 2011. Report of the Combined NinthMeeting of the Conference of the Parties to the Vienna Convention on theProtection of the Ozone Layer and the Twenty-Third Meeting of the Parties tothe Montreal Protocol on Substances that Deplete the Ozone Layer. Nairobi,Kenya: UNEP (UN Doc UNEP/Ozl.Pro.23/11, 8 December 2011).

United Nations Environment Programme. 2011a. HFCs: A Critical Link inProtecting Climate and the Ozone Layer. Nairobi, Kenya: UNEP.

United Nations Environment Programme (UNEP) 2012a. Handbook for theMontreal Protocol on Substances that Deplete the Ozone Layer. Nairobi,Kenya: Montreal Protocol Ozone Secretariat.

United Nations Environment Programme. 2012b. Proposed Amendment to theMontreal Protocol, Submitted by the United States, Canada and Mexico (UNDoc. UNEP/OzL.Pro.WG.1/32/6, 11 May) (‘Proposed Amendment by theU.S., Canada and Mexico’).

United Nations Environment Programme. 2012c. Proposed Amendment to theMontreal Protocol, Submitted by the Federated States of Micronesia (UN


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

Doc. UNEP/OzL.Pro.WG.1/32/5, 11 May) (‘Proposed Amendment byMicronesia’).

United Nations Environment Programme. 2012d. Report of the Twenty-FourthMeeting of the Parties to the Montreal Protocol on Substances that Depletethe Ozone Layer. (UN Doc. UNEP/Ozl.Pro.24/10, 16 November 2012).

United Nations Environment Programme and World MeteorologicalOrganization. 2011. Integrated Assessment of Black Carbon andTropospheric Ozone: Summary for Decision Makers. Nairobi, Kenya: UNEP.

United Nations Environment Programme. 2013. Proposed Amendment to theMontreal Protocol, Submitted by the Federated States of Micronesia (UNDoc. UNEP/OzL.Pro.WG.1/33/4) 16 April (‘Proposed Amendment byMicronesia’).

United Nations Environment Programme. 2013a. Proposed Amendment to theMontreal Protocol, Submitted by Canada, Mexico and the United States ofAmerica (UN Doc. UNEP/OzL.Pro.WG.1/33/3) 16 April (‘ProposedAmendment by Canada, Mexico and the USA’).

U.S. Environmental Protection Agency. 1999a. The Benefits and Costs of theClean Air Act, 1990–2010. Office of Air and Radiation. EPA 4W-R-99-001.http://www.epa.gov/air/sect812/1990-2010/fullrept.pdf

U.S. Environmental Protection Agency. 1999b. The Importance of Motor VehicleAir Conditioning in Climate Protection. Washington, DC: U.S. EPA.

U.S. Environmental Protection Agency. 2007. Achievements in StratosphericOzone Protection: Progress Report. Office of Air and Radiation. EPA 430-R-07-001. http://www.epa.gov/ozone/downloads/spd-annual-report_final.pdf

U.S. Environmental Protection Agency. 2009. Comparing the Climate Impacts ofMobile Air Conditioners. http://www.epa.gov/cpd/mac/compare.htm.(accessed December 31, 2012).

U.S. Environmental Protection Agency. 2012. Report to Congress on BlackCarbon. Washington, DC: U.S. EPA.

U.S. Environmental Protection Agency and Department of Defense. 2008. TheImportance of Military Organizations in Protecting the Climate. Washington,DC: IGSD.

U.S. Patent 7,534,366. 2003. Filed 27 October.U.S. Patent 7,279,451. 2004. Filed 29 April.van der Leun, J.C., and F.R. de Gruijl. 2002. Climate change and skin cancer.

Photochem. Photobiol. Sci. 1:324–26. doi:10.1039/b201025avan der Leun, J.C., R.D. Piacentini, and F.R. de Gruijl. 2008. Climate change and

human skin cancer. Photochem. Photobiol. Sci. 7:730–33. doi:10.1039/b719302e

van Hattem, S., M.J. Aarts, W.J. Louwman, H.A. Neumann, J.W. Coebergh, C.W.Looman, T. Nijsten, and E. de Vries. 2009. Increase in basal cell carcinomaincidence steepest in individuals with high socioeconomic status: results of acancer registry study in The Netherlands. Br. J. Dermatol. 161:840–45.doi:10.1111/j.1365-2133.2009.09222.x

VASA. 2009. Hot Air Newsletter. The Mobile AC, Electrical and CoolingTechnicians of Australia. http://www.vasa.org.au/wp-content/hotair/hot_air_feb09.pdf (accessed December 28, 2012).

Velders, G. J. M., S. O. Andersen, J. S. Daniel, D. W. Fahey, and M. McFarland.2007. The importance of the Montreal Protocol in protecting climate. Proc.Natl. Acad. Sci. USA 104(12): 4814–19. doi:10.1073/pnas.0610328104

Velders, G.J.M., D.W. Fahey, J.S. Daniel, M. McFarland, and S.O. Andersen.2009. The large contribution of projected HFC emissions to future climateforcing. Proc. Natl. Acad. Sci. USA 106:10949–54. doi:10.1073/pnas.0902817106

Velders, G.J.M., A.R. Ravishankara, M.K. Miller, M.J. Molina, J. Alcamo, J.S.Daniel, D.W. Fahey, S.A. Montzka, and S. Reimann 2012. PreservingMontreal Protocol climate benefits by limiting HFCs. Science 335(6071):922–23. doi:10.1126/science.1216414

Vojnikovic B., S. Njiri, M. Coklo, I. Toth, J. Spanjol, and M. Marinovic. 2007.Sunlight andincidence of pterygium on Croatian Island Rab-epidemiologicalstudy. Coll. Anthropol. 31(suppl. 1): 61–62.

Wang L., M. Toda, K. Saito, T. Hori, T. Horii, H. Shiku, K. Kuribayashi, and T.Kato. 2008. Post-immune UV irradiation induces Tr1-like regulatory T cellsthat suppress humoral immune responses. Int. Immunol. 20:57–70.doi:10.1093/intimm/dxm124

Weisler, P. 2008. EPA Presses for Faster Switch to A/C Refrigerant R-1234yf.SAE Automotive Engineering International, News Online, 7 April. http://www.sae.org/mags/aei/6137 (accessed March 20, 2013).

Weisskopf, M. 1987. Ozone depletion worsens, is linked to man-made gas.Washington Post October 1: a. 23.

Wheeler, A.E. 1999. A view of IAQ (indoor air quality) as the century closes.ASHRAE J. November: 35–38.

Wofsy, S.C., and M.B. McElroy. 1974. HOx, NOx, and ClOx: Their role inatmospheric photochemistry.Can. J. Chem. 52:1582–91. doi:10.1139/v74-230

Wofsy, S.C., M.B. McElroy, and N.D. Sze. 1975. Freon consumption:Implications for atmospheric ozone. Science 187(4176): 535–36.doi:10.1126/science.187.4176.535

World Meteorological Organization. 2012. WMO Greenhouse Gas Bulletin: TheState of Greenhouse Gases in the Atmosphere Based on Global Observationsthrough 2011. www.wmo.int/pages/mediacentre/press_releases/pr_965_en.html (accessed December 31, 2012).

Young, O.R. 1999. The Effectiveness of International Environmental Regimes:Causal Connections and Behavioral Mechanisms. Cambridge, MA: MIT Press.

Zaelke, D., S.O. Andersen, and N. Borgford-Parnell. 2012. Strengthening ambi-tion for climate mitigation: The role of the Montreal Protocol in reducingshort-lived climate pollutants. Rev. Eur. Commun. Int. Environ. Law 21(3):231–42. doi:10.1111/reel.12010

Zerefos, C., G. Contopoulos, and G. Skalkeas. 2009. Twenty Years of OzoneDecline: Proceedings of the Symposium for the 20th Anniversary of theMontreal Protocol. Dordrecht, The Netherlands: Springer.

About the AuthorsStephen O. Andersen, PhD, worked for 23 years for the U.S. EnvironmentalProtection Agency in a variety of positions including Deputy Director of theStratospheric Ozone Protection Division and Director of Strategic ClimateProjects in the Climate Protection Partnerships Division. At U.S. EPA he helpednegotiate the Montreal Protocol; created the U.S. EPA Stratospheric Ozone andClimate Protection Awards; started the first U.S. EPA industry–-government part-nerships, including cooperative research projects with the Motor VehicleManufacturers Association (MVMA), the Society of Automotive Engineers(SAE), and the Mobile Air Conditioning Society (MACS); managed the transitionfrom CFC-12 or HFC-134a refrigerants; and co-chaired the Mobile AirConditioning Climate Protection Partnership (MACCPP). He is the author ofbooks and publications about atmospheric protection and has won numerousnational and international awards. He is currently director of research at theInstitute for Governance & Sustainable Development (IGSD) and a Senior ExpertMember of the Montreal Protocol Technology and Economic Assessment Panel.

Marcel L. Halberstadt, PhD, retired in 1998 from the American AutomobileManufacturers Association (AAMA), where he supported industry committeesdealing with regulatory issues addressing automotive emissions and fuel econ-omy, ozone depletion and greenhouse gases and their effect on air quality and theenvironment. He was involved in the development of environmental policy at thelocal, state, national and international level. With Stephen O. Andersen andStephen Seidel at U.S. EPA, he participated in the first project authorized underthe Cooperative Research Act of 1984, which encouraged government–industryresearch in the public interest by reducing potential antitrust liabilities of researchjoint ventures when the work is undertaken in the public interest. Dr. Halberstadtalso helped craft voluntary agreements that accelerated the introduction of ozone-safe refrigerants for motor vehicle air conditioning. He is currently a consultantand the Associate Director of the Michigan Retired Engineer TechnicalAssistance Foundation (RETAF), a not-for-profit group that assists small busi-nesses in improving their pollution prevention and energy conservation efforts.

NathanBorgford-Parnell, JD,MIA, is a law fellow at IGSD, founder of ValkyrieEnergy—a renewable energy consulting firm—and former Peace Corps volun-teer in Albania (2003–2005).


Dow

nloa

ded

by [

Uni

vers

ity o

f C

olor

ado

at B

ould

er L

ibra

ries

] at

07:

36 1

7 A

pril

2014

Stephen O. Andersen policy success story , Marcel L ...whan/ATOC4800_5000/Spring_2017/Mat… ·...

Documents

Transcript of Stephen O. Andersen policy success story , Marcel L ...whan/ATOC4800_5000/Spring_2017/Mat… ·...