Indoor Environmental Quality and Health

Michael ApteIndoor Environment Department

PhilipsVisitApril 2 2007

Indoor Environment Department Mission

• Excellent R&D leading to better understood and reduced pollutant exposures and associated health effects– While maintaining or reducing energy use– With emphasis on the Indoor Environment

Indoors86%

Vehicles6%

Outdoors8%

Why Indoor Environments Are Important

People indoors 90% of timePollutant exposures increase

1000 fold with indoor releaseFor many pollutants, indoor

concentration >> outdoor conc. Very large population affected

frequently by indoor exposuresLarge potential economic

benefits of improved Indoor Environmental Quality (IEQ)

IEQ control has implications for energy consumption

Indoor Environment DepartmentResearch Domain

Energy useEnergy use

ExposuresExposuresHealth effectsHealth effects

Building Design and Operation

Building Design and Operation

ProductivityProductivityOutdoor Air QualityOutdoor Air Quality

Effectiveness of

Control Measures

Effectiveness of

Control Measures

Building Science and Engineering

Physics and Chemistry

Fluid dynamics

Building Science and Engineering

Physics and Chemistry

Fluid dynamics

Pollutant Sources

Pollutant Sources

Research Products: Technologies, Models, Measurement methods, Guidelines, Standards, Information

Research Products: Technologies, Models, Measurement methods, Guidelines, Standards, Information

CostsCostsActivitiesActivities

ConcentrationsConcentrations

ClimateClimate

Statistics

Exposure and risk assessment

Epidemiology

Computing

Statistics

Exposure and risk assessment

Epidemiology

Computing

Research Methods• Laboratory experiments

• Field studies in real buildings– Pollutant source characterization

– Air and pollutant transport measurements

– Exposure characterization

– Evaluate IAQ control measures

– Health and productivity assessments

• Multivariate statistical analyses of data

• Air and pollutant transport modeling

• Modeling of exposures

• Critical reviews

• Input for standards

Recent Research Highlights

Air freshener

Product use in the presence of ozone

Pine oil -based cleaner

Orange oil -based cleaner

Indoor Air Chemistry: Cleaning Agents, Ozone and Toxic Air Contaminants

Motivation • Potential for substantial toxic emissions from cleaning products and

air fresheners, and for reactions of primary emissions with ozone• Poor understanding of primary emissions and reactionsApproach • Measurement of primary VOC emissions plus bench and room-scale

studies of ozone reactive chemistry

Key results • 2-butoxyethanol exposure

may approach or exceed California’s reference level

• Terpenes + ozone can yield high levels of formaldehyde and ultrafine aerosol particles

Significance• Implications for product

selection and formulation

Indoor Particle Tracking & Resuspension

MOTIVATION

• Tracking & resuspension affect exposures.

• Magnitudes not quantified and physical processes not understood.

TRACKING BY FOOT TRAFFIC

RECENT PROGRESS

• Measured size-resolved particle tracking by foot steps for several surfaces and stepping sequences.

• Measured, in real time, size-resolved particle resuspension from clothing for different clothing material and activities.

KEY FINDINGS

• Shoe-to-floor and floor-to-shoe mass transfer is 2-25% for a single step.

• Shoe-to-floor and floor-to-shoe mass transfer decreases with multiple steps.

• 4-11% of particle mass on clothing was resuspended during 30 minutes of walking in place.

Step number on clean floor

0 2 4 6 8 10 12

Fra

cti

on

tra

nsf

erre

d f

rom

sh

oe

To

cle

an f

loo

r in

a s

ing

le s

tep

0.00

0.05

0.10

0.15

0.20

Cu

mu

lative fraction

tran

sferred

0.00

0.15

0.30

0.45

0.60

Single-step fraction transferred

Cumulative fraction transferred

MOTIVATION

• What types of sensors should be used to detect and locate an unknown indoor release? Where should they be placed?

• Needed algorithm to “fuse” multiple streams of data from disparate sensors, in real time, for event reconstruction.

Optimal Sensor Networks for Rapid Response to Toxic Pollutant Releases in Buildings

RECENT PROGRESS

• Bayesian probabilistic algorithm that updates model predictions rapidly, using any type of sensor data.

• In FY06, (1) developed statistics to interpret data from threshold-type sensors; (2) tested algorithm against data from a real building; (3) evaluated performance of monitoring networks for a variety of sensor performance characteristics.

Three-Floor Building

0

2

4

6

20 60 120 180

Sensor Cycle Time (sec)T

ime

to

loca

te s

ou

rce

(m

in)

Sensor detection limit = 20 mg/m3

SIGNIFICANT RESULTS

• To locate source, sensor cycle (reset) time is often more critical than sensor detection limit.

• Slower but more accurate sensors are often better than faster but less accurate sensors.

Indoor Residential Chemical Emissions as Risk Factors for Children’s Respiratory Health

• Motivation– Unexplained increase in asthma/allergies worldwide in recent decades – Influence of indoor chemical emissions on allergies and asthma largely

unrecognized

• Approach – critical review of scientific literature

• Results – many common indoor chemicals or sources associated with large increase in respiratory or allergic effects in children, most consistently for formaldehyde, plastics

• Significance – findings provide justification for preventive actions for formaldehyde exposures, and document need to confirm the many other reported relationships with adverse health effects in children

Formaldehyde or particleboard

20– 700 % increase (12 findings)

20, 30, 30, 40, 40, 40, 40, 60, 70, 80, 100, 700 %

Plasticizers or plastics

0 – 1,170 % increase

(12 findings)0, 10, 40, 40, 50, 90, 90, 140, 190, 190, 240, 1169 %

Increased asthma-related effects in children

Impact of Temp. and Ventilation on Work Performance

Motivation• Economics drives decisions

about building design and operation

• IEQ-productivity research data not readily usable for cost-benefit assessments

Approach• Synthesize and statistically fit

research data relating objective measures of work performance with temperature and ventilation

Results• Best estimates of quantitative

relationships to aid decision making

-10

010

20

15 20 25 30 35

Temperature (oC)

reported in each study

composite weighted

90% CI of composite weighted

sample size weighted

unweighted

P p

er o C

.8.8

5.9

.95

1R

ela

tiv

e P

erfo

rman

ce

15 20 25 30 35Temperature (°C)

Measurement of Outdoor Air (OA) Flows into HVAC SystemsMotivation

• OA supply affects health & energy

• OA supply rarely measured and poorly controlled

• Measurement of OA intake rate is technically challenging

Approach• Lab & field testing of

emerging real-time OA measurement technologies

• Experiments identified causes of and cures for measurement errors

Return air damper

Return air damper

Intake louverIntake louver

Return AirReturn Air

OAOA

OA damperOA damper

Supply air

Supply air

OA Meas. System

Location

OA Meas. System

Location

Findings• 3 of 4 technologies tested can work well –

If used with proper system of louvers, dampers, P transducers

• Most accurate system measures velocities inside OA intake louver, not downstream

DeltaQ Method of Measuring Air Leakage in Residential Ducts

Motivation• 20-40% of HVAC energy is wasted through duct leaks• No practical and accurate leakage test methods existed

-1000

-500

0

500

1000

1500

-30 -20 -10 0 10 20 30

Pressure Difference, Pa

Air

Flo

w, c

fm

-80

-60

-40

-20

0

20

40

60

80

100

120

Del

taQ

Flo

w, c

fm

Air Handler OffAir Handler OnDeltaQ

Approach• Measure flow through

building envelope vs. P with and without air handler operation

• Data analyses gives leakage to outdoors

Results• New test method works.

Has been included in ASTM Test Method

Efficacy of Intermittent VentilationMotivation• Want to be able to ventilate buildings at time-varying rates for peak

power control, or to reduce exposures to outdoor pollutants

Efficacy Contours

0

1

2

3

4

5

0 0.2 0.4 0.6 0.8

Under-ventilation Fraction (-)

Nom

inal

Tur

n-ov

er, N

(air

chan

ges)

10% Efficacy

30% Efficacy

50% Efficacy

70% Efficacy

90% Efficacy

Approach• Use equivalent air pollutant

dose as metric

• simplified physical modeling

Results• Ventilation efficacy

determined as function of ventilation turn-over (N) & under-ventilation fraction

• Being incorporated into standards

))((5.0 ttACHACH lowhighloweqN

Miniature Particle Matter (PM) Monitor• Problem: PM monitors costly, bulky,

poor for population-based exposure assessment & epidemiology

• Collaboration: EETD, ED, UC BSAC• Approach: MEMs PM sensor array chip• PM collection: Thermophoresis• Mass Detection: Film Bulk Acoustic

Resonator (FBAR) array chip• Source Characterization: UV and NIR

Absorbance (not fully completed)• Status: Completed prototype,

Validated in lab and field, final report, Patented, LOD 18 g m-3

• Vision: PM sensors embedded in cell phone, GPS, high density data networksFunding: CARB

Staff:Apte, Gundel, Black

Improving Ventilation and Saving Energy In Relocatable Classrooms (RCs)

• Problem: About 600,000 RCs in U.S. -> 16M Students– HVAC noise, poor ventilation, inefficient heat pumps

– Cannot meet State and ASHRAE Standards (T24, 62.1)

• Collaboration: EETD, Bard Mfg., Geary Pacific Corp

• Approach: Specify, develop, lab & field validate, bring new HVAC product to market

– Noise: 55 dB(A) -> 35-45 dB(A)

– Efficiency improvement: Cooling +38% Heating +44%

– Ventilation: continuous @ 15 CFM/occupant (meets T24)

– Refrigerant: R410A (non CFC)

• Status: Validated in Lab and Field

Commercialized

• Specification: CHPS RC standard10

SE

ER

IHP

AC

Daily average CO2 (ppm)

North CA South CA

5000

3750

2500

1250

0

ASH

RA

E 62.1 >

Bard Quiet Climate II

Ambient Ozone and Building-Related Symptoms

• Problem: Identify cause of building related symptoms (BRS)

• Data: USEPA BASE Study from 100 Blds., ambient ozone

• Hypothesis: Ozone mediated indoor chemistry -> Toxic and irritating reaction products

• Multivariate* association (p<0.05) between ambient ozone and BRS

• Ozone mitigating HVAC strategies crucial

for remediation

0%5%

10%15%20%25%30%35%40%45%50%

Upper Respiratory Dry Eyes Neurological Headache

BRS Prevalence Reduction Potential

Max -> Median Max-> Min

Compound R C=O benzene -0.29* n ethylbenzene -0.19 n o-xylene -0.12 n d-limonene 0.11 n naphthalene 0.13 n phenol 0.26 n ethyl acetate 0.12 y formaldehyde 0.18+ y TXIB 0.19 y acetaldehyde 0.28* y texanol 1&3 0.32* y hexanal 0.38* y pentanal 0.40* y

Un

sa

tura

ted

nonanal 0.60** y n-undecane 0.11 n chloromethane 0.24* n 2-ethylhexanol 0.25 n 2-butoxyethanol 0.32* n 1-butanol 0.38* n S

atu

rate

d

ethanol 0.49+ n

*Adjusted for sex, environmental sensitivities, age,smoking status, thermal exposure, dCO2, RH, 1,2,4TMB, HDD and CDD, and season