March 26, 2004 EAS 4/8803 1

EAS 4/8803: Experimental Methods in AQWeek 11:

Air Quality Management (AQM)Clean Air Act (History, Objectives, NAAQS)Emissions and Atmospheric Trends (Links)Principal Measurement Techniques (NOx, CO, SO2)

Measurement of CO (Exp 5)NDIR Method (Interferences, Stability, DL, Precision, Accuracy)

Controlling O3 and PM2.5

Principal Measurement Techniques (O3, PM2.5)Atmospheric Transport & Photochemistry (NOx vs VOC, SOA)Controlling O3, Emissions and Trends (GA)

Measurement of O3 (Exp 6)UV Absorption (Interferences, Stability, DL, Precision, Accuracy)

March 26, 2004 EAS 4/8803 2

GEORGIA: PM 2.5 Arithmetic Mean

10.0

15.0

20.0

25.0M

acon

Alli

ed C

hem

.

Mac

on F

ores

try

Sav

. Mar

ket S

t.

Sav

. Mer

cer

Ath

ens

Fore

st P

ark

Ken

nesa

w

Sou

th D

eKal

b

Dor

avill

e

Alb

any

Rom

e

Atl.

E. R

iver

s S

ch.

Atl.

F.S

. # 8

Bru

nsw

ick

Gw

inne

tt

Gai

nesv

ille

War

ner R

obin

s

Val

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a

Col

umbu

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.D.

Col

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s C

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d.

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Aug

usta

Med

. Col

.

Aug

usta

Bun

galo

w R

d.

Ros

svill

e

San

ders

ville

Gor

don

Site

mg/

m3

1999 2000 2001 2002

March 26, 2004 EAS 4/8803 3

GEORGIA: 3 year average of PM 2.5 Annual Arithmetic Mean

0.0

5.0

10.0

15.0

20.0

25.0

Mac

on A

llied

Che

m.

Mac

on F

ores

try

Sav

. Mar

ket S

t.

Sav

. Mer

cer

Ath

ens

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st P

ark

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nesa

w

Sou

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eKal

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avill

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any

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Atl.

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iver

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ch.

Atl.

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Site

mg/

m3

99-01 00-02

March 26, 2004 EAS 4/8803 4

Average total precipitation in Atlanta during ozone season (May - Sep)

17.220.3 20.1

28.5

0.0

5.0

10.0

15.0

20.0

25.0

30.0

1998-2000 Normal 2001-2003 2003

Ave

rage

Pre

cipi

tatio

n (in

)

March 26, 2004 EAS 4/8803 5

Average # of days per ozone season (May-Sep) with maximum temperature ≥ 90F in Atlanta

48.7

32.8

23.0

7.0

0.0

10.0

20.0

30.0

40.0

50.0

60.0

1998-2000 Normal 2001-2003 2003

# of

day

s pe

r yea

r with

Tm

ax ≥

90F

March 26, 2004 EAS 4/8803 6

0.060

0.080

0.100

0.120

0.140

1981 1984 1987 1990 1993 1996 1999 2002Year

Thre

e Ye

ar A

vera

ge o

f 4th

Max

for O

zone

(ppm

v)

Atlanta Augusta Columbus Macon

The State of the Air in Georgia (ozone)

Attain“Good”

NAAQS

Nonattain“Bad”

Can we expect recent cool & wet summers to continue?

March 26, 2004 EAS 4/8803 7

If we can’t depend on theweather, then what canwe control?

Volatile Organic Compounds (VOCs)

Nitrogen Oxides (NOx)

Fuels, Paints, Solvents, &

Vegetation

Combustion Processes

Ozone (O3)Smog+

March 26, 2004 EAS 4/8803 8

Photochemical Processes Leading to O3 and PM

SOA

NOz

An Assessment of Tropospheric Ozone Pollution, A North American Perspective, NARSTO, National Acad. Press, 2000.

March 26, 2004 EAS 4/8803 9

VOC Sources in Columbus MSA (2000)

Anthropogenic Sources:• Gasoline Vehicles• Solvents (Paints,

Automotive Products, Adhesives, etc.)

• Carbon Black• Lawn & Garden• Bakeries

Total: 385 tons per day

March 26, 2004 EAS 4/8803 10

Ozone IsoplethsArea of effective VOC control (most often highly populated areas)

Volatile Organic Compounds (VOC)

Nitr

ogen

Oxi

des

(NO

x) Constant [O3]

Low [O3]

High [O3]

NOx control effective(areas with high biogenics)

March 26, 2004 EAS 4/8803 11

NOx Sources in Columbus MSA (2000)Total: 42 tons per day

March 26, 2004 EAS 4/8803 12

Implementation of NOx Controls Since 2000,Full Implementation Expected by 2007

• Annual, stricter vehicle emissions inspections• Open burning ban in 45 counties• Georgia Power phasing in NOx controls• 30 ppm sulfur gasoline in 45 counties • GA Power plants achieve NOx reduction in 45 counties• Stricter peaking generator rule• Large industrial source NOx reductions

March 26, 2004 EAS 4/8803 13

2007 NOx Emissions in Georgia by Region

0

50

100

150

200

250

300

NO

x em

issi

ons

(tons

/day

) MOBILEPOINT

AREANONROAD

MOBILE 277.4 36.7 22.5 14.9 90.1 135.0 57.6

POINT 126.6 16.8 15.8 0.6 34.0 96.5 23.7 142.2

AREA 61.5 3.0 2.7 2.5 11.6 19.8 7.9

NONROAD 134.2 11.9 8.2 5.2 29.6 70.1 21.3

Atlanta Macon Augusta Columbus N. Georgia S. Georgia C. Georgia Scherer (92) + Branch (50)

2007 NOx Emissions in GA by Region and SourceIf Fully Implemented

Georgia Total: 1480 tons/day

Alabama Total (not shown): 998 tons/day

March 26, 2004 EAS 4/8803 14

Significant improvements in regional air quality by 2007with no additional controls (current SIP fully implemented)

March 26, 2004 EAS 4/8803 15

Estimated Change in Regional Peak 8-hour Surface Ozone from August 17th, 2000 to 2007 under the Existing Federal Control Strategies (ppbv)

Region Atlanta Augusta Columbus Macon

Observed 139 111 114 134

4-km grid 132 118 100 89 108 96 143 128

% reduction 11% 11% 11% 10%

Region Maximum Daily Peak 8-hour OzoneObserved / Simulated 2000 2007

But will these existing controls be enough?

March 26, 2004 EAS 4/8803 16

0.0880.086 0.087

0.085

0.089

0.094

0.090

0.060

0.070

0.080

0.090

0.100

1981 1984 1987 1990 1993 1996 1999 2002Year

Thre

e Ye

ar A

vera

ge o

f 4th

Max

for O

zone

(ppm

v)The State of the Air in Columbus, Georgia

8-hour Average Ozone Design Values

Attain“Good”

NAAQS

Nonattain“Bad”

March 26, 2004 EAS 4/8803 17

0.0880.086 0.087

0.085

0.089

0.094

0.090

0.060

0.070

0.080

0.090

0.100

1981 1984 1987 1990 1993 1996 1999 2002Year

Thre

e Ye

ar A

vera

ge o

f 4th

Max

for O

zone

(ppm

v)The State of the Air in Columbus, Georgia

8-hour Average Ozone Design Values and Theoretical 10% Improvement

Attain“Good”

NAAQS

Nonattain“Bad”

Reality

Theory

Goal

March 26, 2004 EAS 4/8803 18

Clarification CO Accuracy Assessment

Time (minutes)

COspan4,0COspan1,0

COspan1

COZA COZA

COspan2

COspan3

COspan4

CO

Ana

lyze

r Sig

nal

(V)

Zero-air/Zero-mode = baseline

Zero-air

CO0

CO0

COnom]1

5 V

COnom]2

COnom]3

COnom]4

zero-mode zero-mode

COsensi (ppb/V) = [COnomi] / COspani

ZTeffi = (COspani – COspani,0) / (COspani – CO0) > 0.9!!

COnet (V) = COraw – CO0ipol CO (ppb) = COnet * COsens

DL (ppb) = t * STD(CO0*) * COsens

P (%) = t * STD(COsens) / AVG(COsens) *100

A1 (%) = (slope{[COnomi] / COspani} -1000)/1000 *100Rel. diff. of slope to nom. detector sens = 1000 ppb/VA2 (%) = {[((Xj))2 (COsens/Xj)2]}1/2

…from error propagation analysis.

March 26, 2004 EAS 4/8803 19

O3 Method: UV Absorption

I = I0 e- c l

= 308 cm-1 (@STP: 0oC, 760Torr)

l = 38 cm

254 nm

March 26, 2004 EAS 4/8803 20

O3 Primary Standard Calibrator

I = I0 e- c l

= 308 cm-1 (@STP: 0oC, 760Torr)

l = 38 cmTo

analyzer under cal

capped

Zero Air 254 nm

internal vent

[O3]nomC

March 26, 2004 EAS 4/8803 21

Goals

1. Basic Functionality Test2. Determine Analyzer Performance

(DL, sensitivity, precision and accuracy) 3. Determine the NO2 Photolysis Rate from PSS

assumptions and discuss 4. Discuss differences in O3 measured between

outdoor and indoor air

March 26, 2004 EAS 4/8803 22

1. Functionality Tests

• Detectors Performance check• System Leaks and Pump check• Ozone scrubber efficiency check

March 26, 2004 EAS 4/8803 23

2. Analyzer Performance

Time (minutes)

O3span1

O30 O30

O3span2

O3span3

O3span4

O3 A

naly

zer S

igna

l (V

)

Zero-air

O3nom]1

10 V

O3nom]2

O3nom]3

O3nom]4

O3sensi (ppb/V) = [O3nomi] / O3spani

O3 (ppb) = O3raw * O3sens

DL1 (ppb) = t * STD(O30) * O3sens

DL2 (ppb) = i-cept{[O3nomi] / O3spani}

P (%) = t * STD(O3sensi) / AVG(O3sensi) *100

A1 (%) = (slope{[O3nomi] / O3spani} -20)/20 *100Rel. diff. of slope to nom. detector sens = 20 ppb/VA2 (%) = {[((Xj))2 (O3sens/Xj)2]}1/2

…from error propagation analysis.Groups look for their individual

“O3raw__.xls” data file on http://arec.gatech.edu/teaching

March 26, 2004 EAS 4/8803 24

3.1 Determine jNO2 from PSS

Assuming ambient O3 in photochemical steady-state (PSS) with NO and NO2, calculate jNO2 and discuss by comparing with literature values.

NO2 + hv (jNO2) NO + O (R1) O + O2 + M O3 + M (fast, not rate-limiting) (R2) O3 + NO (k3) NO2 + O2 (R3)

1110)/1400(

12

3 10687.215.27325.1013

102

sppbvx

TK

mbarP

exk T

Assuming first-order homogeneous reaction (R3),andd[NO2]/dt = k3 [O3][NO] - jNO2 [NO2] = 0

yieldingjNO2 = k3 [NO] [O3] / [NO2] in s-1

March 26, 2004 EAS 4/8803 25

3.2 Discuss jNO2 Diurnal ProfileThe photolysis rate coefficients (jNO2) provided here exemplarily, were calculated using a radiative transfer model (Zeng et al., 1996), which is based upon the Stamnes discrete ordinates model modified to solve the radiative transfer equation in pseudo-spherical coordinates. The discrete ordinates code was run with eight streams. The surface albedo was assumed to be 5%, and the total aerosol optical depth was parameterized in terms of visual range. The model assumes a constant visual range of 25 km for the lowest 2 km, a logarithmically decreasing aerosol optical depth above this, as well as a single scattering albedo of 0.99 and an asymmetry parameter of 0.61, which are both wavelength-independent. The jNO2 values were then scaled linearly by the flat-plate Eppley-UV (290-385 nm) measurements and by their ratio to the radiative transfer model clear-sky irradiance to account for the actual cloud and aerosol effects on jNO2. This scaling helps to correct for any errors made by the visual range assumptions.

8x10-3

6

4

2

0

j NO

2 (s

-1)

00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00

Time of Day 6/29/94 (CST)

Consult references Volz et al., 1996, and Zeng et al., 1996.

Retrieve above sample data as “jNO2sampleday.xls” from

http://arec.gatech.edu/teaching

March 26, 2004 EAS 4/8803 26

4. Discuss O3 indoor vs outdoor differences

• Determine indoor and outdoor O3 mixing ratios for a sample data set.

• Evaluate diurnal profiles of both individually and as difference.

• Discuss observed differences.

50

40

30

20

10

0

O3

Indo

or (p

pbv)

50403020100O3 Outdoor (ppbv)

O3slope= 0.96 +-0.01icept= -0.1 +- 0.2r^2= 0.932

Look for “O3inoutday.xls”

At http://arec.gatech.edu/teaching