Appendix A 

Sensitivity of Ozone Concentrations in 

Atlanta to NOx and VOC Controls Inside and 

Outside the Nonattainment Area 
Appendix A 

Sensitivity of ozone concentrations in Atlanta to NOx and VOC controls 

inside and outside the nonattainment area 

Introduction 

GA-EPD has performed an analysis of the sensitivity of ozone concentrations to 

reductions in emissions of both nitrogen oxides (NOx) and volatile organic compounds 

(VOCs). The analysis was based on the Visibility Improvement State and Tribal 

Association of the Southeast (VISTAS) modeling, using the “Base D” emissions 

inventory (for both 2002 and 2009), and CMAQ version 4.4 with the CB-IV chemical 

mechanism. A 12 km modeling grid was used, covering most of the southeastern USA. 

The episode modeled was May 25 – June 25, 2002, as it contained many days of elevated 

ozone concentrations and has been found representative of longer term trends in ozone 

concentrations. More details regarding the model setup and sensitivity analysis can be 

found in Marmur et al., 2005. 

Methodology 

CMAQ was utilized to model the reductions in ozone from the post 2002 operation of 

SCRs at major coal-fired power plants outside of the Atlanta non-attainment area (NAA). 

These included SCRs on units 3&4 at Plant Bowen located in Bartow County (61.1 tonper-day NOx controlled), SCRs on units 1&2 at Plant Wansley Heard County (51.7 TPD 

NOx controlled) and the switch to Powder River Basin (PRB) coal at Plant Scherer 

Monroe County (24.2 TPD reduction in NOx emissions compared bituminous coal 

combustion). These reductions were then compared with those from ground level VOC 

controls in the Atlanta 20-county NAA (10% reduction from anthropogenic ground-level 

VOC emissions; 49.3 TPD). Also reported are the expected reductions in ozone 

concentrations from potential ground-level NOx controls in the Atlanta 20-county NAA. 

The purpose of this comparison is to evaluate the efficiency of NOx controls from outside 

the Atlanta NAA and of VOC controls within the Atlanta NAA in terms of reductions in 

ozone concentrations. Such an evaluation can help determine whether existing (post 2002 

A-1 
ozone season) NOx controls outside of the Atlanta NAA overweigh any potential VOC 

controls within the NAA. 

Below is a summary of the cases modeled (also see Table 1): 

Case 1: NOx reductions from SCRs installed and operated at GA-Power Plant Bowen 

starting from the 2003 ozone season (units 3&4; 61.1 TPD NOx controlled 

compared to the pre-installation/operation conditions). 

Case 2: NOx reductions from SCRs installed and operated at GA-Power Plant Wansley 

starting from the 2003 ozone season (units 1&2; 51.7 TPD NOx controlled 

compared to the pre-installation/operation conditions). 

Case 3: NOx reductions from the switch to PRB coal at GA-Power Plant Scherer; 24.2 

TPD reduction in NOx emissions during the 2003 ozone season (55.7 TPD) 

compared to the 2002 ozone season (79.8 TPD). 

Case 4: A 10% reduction in emissions of anthropogenic, non-EGU, ground level VOC 

emissions in the Atlanta 20 counties NAA (a potential reduction of 49.3 TPD). 

Case 5: A 10% reduction in emissions of anthropogenic, non-EGU, ground level NOx

emissions in the Atlanta 20 counties NAA (a potential reduction of 38.0 TPD). 

Table 1: Summary of emissions reduction scenarios modeled 

Case # Plant/Region modeled TPD reduction 

1 Bowen units 3&4 (benefits of existing SCRs) 61.1 (NOx) 

2 Wansley units 1&2 (benefits of existing SCRs) 51.7 (NOx) 

3 Scherer (use of PRB coal) 24.2 (NOx) 

4 10% anthropogenic VOC controls in the Atlanta NAA 49.3 (VOC) 

5 10% anthropogenic NOx controls in the Atlanta NAA 38.0 (NOx) 

Results 

Reductions in daily maximum 8-hour ozone concentrations for each of the above cases, 

along with the modeled base-case concentrations (based on both 2002 and 2009 VISTAS 

Base D emissions), are shown in Figure 1. 

A-2 
-1.0

-0.6

-0.2

0.2

0.6

1.0

1.4

1.8

2.2

2.6

3.0

5/25

5/27

5/29

5/31

6/2

6/4

6/6

6/8

6/10

6/12

6/14

6/16

6/18

6/20

6/22

6/24

Date

Reduction in max 8-hr O3 

(ppb)

20

30

40

50

60

70

80

90

100

110

120

Max 8-hr O3 (ppb)

Case 1 Case 2 Case 3

Case 4 Case 5 max 8-hr O3 (2002 emissions)

max 8-hr O3 (2009 emissions)

Figure 1: Daily reductions in maximum 8-hour ozone concentrations, along with base 

case concentrations, at the Atlanta Confederate Avenue site. Green rectangles indicate 

days in which the 2002 base case daily 8hr maximum ozone concentration was above 85 

ppb (used for the calculations presented in Table 2) 

Case 1 (modeled benefits of existing SCRs at Plants Bowen) shows the highest benefits 

in terms of ppb reduction in 8-hour ozone concentrations at the Atlanta Confederate 

Avenue site, with reductions of up to 2.9 ppb. Also evident are the impacts of NOx

controls at Georgia-Power Plants Wansley and Scherer, and the potential benefits from 

controlling ground level NOx sources in the Atlanta metropolitan area (maximum 

reductions of 2.0, 1.8 and 1.9 ppb, respectively). VOC controls seem less effective for 

Atlanta, with a maximum reduction of 0.8 ppb in maximum daily 8-hr ozone 

concentrations. 

To account for the fact that the emissions reductions scenarios modeled here differ in 

magnitude (TPD controlled), we also normalized the reductions in ozone to the tons of 

NOx or VOC controlled. The average and normalized reductions in ozone, for days in 

A-3 
which the 2002 base case concentration was above 85 ppb (7 days total), are given in 

Table 2. 

Table 2: Average reductions in 8-hour ozone concentrations (ppb) and normalized 

reductions (ppt O3 / TPD) for days in which the 2002 base case concentration was above 

85 ppb (7 days total) 

Case # Average reduction (ppb) Normalized reduction 

1 0.78 12.8 ppt O3 / TPD NOx

2 0.39 7.6 ppt O3 / TPD NOx

3 0.21 8.6 ppt O3 / TPD NOx

1+2+3 1.4 10.0 ppt O3 / TPD NOx

4 0.30 6.0 ppt O3 / TPD VOC 

5 1.2 31.4 ppt O3 / TPD NOx

These data once again demonstrate the benefits of the existing SCRs at plants Bowen and 

Wansley and of the use of PRB coal at Plant Scherer (12.8, 7.6 and 8.6 ppt/TPD, 

respectively). The sensitivity of ozone to ground level VOC controls is lower (6.0 

ppt/TPD). The combined effect of controls at Bowen, Wansley and Scherer (approximate 

average reduction of 1.4 ppb) is substantially higher of that that could realistically be 

achieved by anthropogenic VOC controls (an approximate average reduction of 0.3 ppb 

per 10% reduction in VOC emissions). The sensitivity of ozone to ground level NOx

emissions in the Atlanta NAA (Case 5) is substantially higher than any of the other cases 

presented here (31.4 ppt/TPD compared to 6.0-12.8 ppt/TPD). 

Also evident in Figure 1 are the impacts of NOx emissions reductions expected by 2009, 

compared to the 2002 case (most of the reductions are from the mobile-source and EGU 

sectors; for more details see Marmur et al., 2005). This further demonstrates that 

ongoing reductions in NOx emissions (such as from fleet turnover) will continue to lower 

concentrations of ozone in the Atlanta NAA. 

A-4 
References 

Marmur, A., Boylan, J., Khan, M., and Cohan, D. (2005), 8-Hour Ozone and PM2.5

Modeling to Support the Georgia SIP, 4th Annual CMAS Models-3 Users' Conference, 

Chapel Hill, NC (http://www.cmascenter.org/conference/2005/abstracts/7_6.pdf), 

included as Appendix A Exhibit 1, below. 

A-5 
Appendix A Exhibit 1 

8-Hour Ozone and PM2.5 Modeling to Support the Georgia SIP 
1

8-HOUR OZONE AND PM2.5 MODELING TO SUPPORT THE GEORGIA SIP

Amit Marmur*, James Boylan, Maudood Khan, and Daniel Cohan

Environmental Protection Division, Georgia Department of Natural Resources, Atlanta, GA, USA

1. INTRODUCTION

With the onset of the new National Ambient Air

Quality Standards (NAAQS) for ozone and fine

particulate matter (PM2.5), Georgia now confronts

nonattainment for multiple pollutants and regions.

While 13 Atlanta counties had historically violated

the now-revoked 1-hour standard for ozone of

0.12 ppm (below 125 ppb), a larger Atlanta region

(Figure 1), along with Macon, violate the new 8-

hour standard of 0.08 ppm (below 85 ppb). Also,

an early action compact (EAC) has been

developed to reduce ozone in Chattanooga and

Augusta. Atlanta, Macon, Floyd County, and

Chattanooga (Figure 2) violate the annual PM2.5

standard (15 μg/m

3

), marking the first time that

Georgia must develop state implementation plans

(SIPs) to control particulate matter. SIPs

demonstrating plans of action for future attainment

are due in 2007 for ozone and in 2008 for PM2.5.

These plans will detail local control measures to

complement expected emissions reductions from

federal actions, including the Clean Air Interstate

Rule for power plants and more stringent federal

standards for vehicles, fuels, and non-road

equipment.

Fig. 1. Georgia 8-hour ozone non-attainment areas

(Chattanooga is an EAC area).

*Corresponding author: Amit Marmur, Environmental

Protection Division, Georgia Department of Natural

Resources, 4244 International Parkway, Suite 120,

Atlanta, GA 30354; e-mail:

amit_marmur@dnr.state.ga.us

Fig. 2. Georgia annual PM2.5 non-attainment areas.

2. MODELING SYSTEM AND GRID

CONFIGURATION

In order to evaluate and develop efficient

emission control strategies and demonstrate future

attainment with the NAAQS, the Georgia

Environmental Protection Division (GA EPD) is

using the MM5/SMOKE/CMAQ modeling system.

The modeling used in these SIP attainment

demonstrations is based on the VISTAS regional

haze modeling which includes annual simulations

of 2002, 2009, and 2018 at 36 km (continental

U.S.) and 12 km (Eastern U.S.) grid resolutions.

In addition, GA EPD has developed a smaller 12

km grid (referred to as ALGA12) that covers

Georgia and Alabama (and their adjacent states)

and a 4-km grid over Georgia (referred to as GA4).

While annual PM2.5 modeling simulations will be

conducted on the ALGA12 grid, only 4 months of

the 2002 ozone season (05/20/02-09/20/02) will

be simulated on the more refined GA4 grid

3. EPISODE SELECTION

In order to most efficiently design emission

control strategies to reduce PM2.5 and ozone, GA

EPD is performing episodic emission sensitivities

on a winter (11/19/02-12/19/02) and a summer

episode (05/25/02-06/25/02). To objectively select

representative time periods for sensitivity

simulations, GA EPD selected the above episodes

based on a classification and regression tree

(CART) analysis. CART analysis examines
2

historical records of meteorology and pollutant

concentrations to identify “bins” of days with

similar conditions. Episodes are then selected to

capture a spectrum of representative conditions.

For ozone, which is subject to a standard based

on peak days, a one-month summertime episode

was selected that included all “key bins” of most

typical polluted conditions. For PM2.5, which is

subject to an annual average standard, the

summer episode was paired with a one-month

winter episode to capture a broad range of both

polluted and relatively clean conditions. These

episodes were selected based on a CART

analysis to ensure that a variety of meteorological

conditions important to PM2.5 and ozone formation

were simulated. A histogram comparing frequency

of occurrence of key high ozone bins during the

entire eight-year period (1996-2003), the year

2002, and the chosen summer episode (05/25/02-

06/25/02) (Figure 3) shows that this episode

represents all key ozone conducive meteorological

conditions in Atlanta. Under/over representation of

specific bins (e.g., bin 21) can be corrected by

assigning weights to the different bins. A similar

histogram for PM2.5 (Figure 4), covering both

summer and winter episodes, shows that most key

PM2.5 bins are captured as well.

Ozone Key Bin Frequency for Atlanta

0

1

2

3

4

5

6

7

8

26 14 9 16 21

Percent Contribution

All Years 2002 GA Episode

Fig. 3. Frequency of CART bins for ozone for the period

1996-2003, the year 2002, and the selected episode.

PM2.5 Bin Frequency for Atlanta

0

10

20

30

40

50

1 4 3 16 10 28 5 20 7 35 31 36 26 19 11 15 18 22 23 24

Percent Contribution

All Years 2002 GA Episodes

Fig. 4. Frequency of CART bins for PM2.5 for the period

2000-2003, the year 2002, and the selected

episodes.

4. PROJECTED EMISSIONS REDUCTIONS

BY 2009 AND THEIR EFFECT ON OZONE

AND PM2.5 LEVELS

Since Georgia’s attainment status will be

evaluated in 2010, sensitivity runs are conducted

using the VISTAS 2009 emissions inventory. The

following is a preliminary analysis of the impact of

projected regional reductions in emissions (2009

inventory compared to 2002) on ozone and PM2.5

concentrations.

4.1 Projected Emissions Reductions by

2009 compared to 2002

Comparing the Georgia 2002 and 2009

inventories (Figure 5), reductions of 24%, 34%

and 14% are observed for NOx, SO2 and VOCs,

respectively.

0

100

200

300

400

500

600

700

800

NOx

2002

NOx

2009

SO2

2002

SO2

2009

VOC

2002

VOC

2009

Thousand Tons

Area

(VOC only)

Point

(VOC only)

Misc.

Industrial

Other Fuel

Combust.

EGU

NonRoad

OnRoad

Fig. 5. Comparison between the 2002 and 2009 Georgia

Emissions Inventory

4.2 Reductions in ozone and PM2.5

based on the 2009 inventory

The following is a preliminary analysis of

reductions in ozone and PM2.5 from controls

already in the process of being implemented (as

shown in Figure 5).

Time-series plots for ozone using the 2002

and 2009 inventories for a central Atlanta site

(Confederate Avenue, Figure 6) and a suburban

downwind site (Conyers, Figure 7) show

reductions of up to 12 ppb in the daily maximum 8-

hour ozone concentration. Using these simulated

values for the sensitivity episode of 5/25/02-

6/25/02 and a cutoff value of 75 ppb, Relative

Reduction Factors (RRF, the ratio between
3

controlled and uncontrolled case concentrations)

were calculated for these sites, and resulted in a

RRF of 0.9. When these ratios are applied to the

Design Values (DV, weighted average of the forthhighest 8-hour ozone concentration over a five

year period centered around the modeling year) at

each site, a future (2009) DV is obtained. In the

preliminary analysis conducted here (accounting

for only one month of modeling and only two

specific sites/gird-cells), the future DVs obtained

are 86 ppb (0.9 x 95 ppb, the DV for 2002) for the

Confederate Avenue site and 82 (0.9 x 91 ppb, the

DV for 2002) for the Conyers site. Based on this

preliminary and “informal” analysis, it would seem

that the Confederate Avenue site would not attain

the standard (>85 ppb), while the Conyers site

would attain (<85 ppb).

0

20

40

60

80

100

120

140

5/25/02

5/27/025/29/02

5/31/02

6/2/026/4/02

6/6/02

6/8/02

6/10/02

6/12/026/14/02

6/16/02

6/18/02

6/20/026/22/02

6/24/02

ppb

-2.0

0.0

2.0

4.0

6.0

8.0

10.0

12.0

Difference, ppb

Max8hrO3 2002 Max8hrO3 2009 Max8hrO3 diff.

Fig. 6. Time-series of modeled daily maximum 8-hour

ozone concentrations at the Confederate Avenue

(Atlanta) site based on 2002 and 2009 emissions.

0

20

40

60

80

100

120

5/25/02

5/27/02

5/29/02

5/31/02

6/2/02

6/4/02

6/6/02

6/8/02

6/10/02

6/12/02

6/14/02

6/16/02

6/18/02

6/20/02

6/22/02

6/24/02

ppb

0.0

2.0

4.0

6.0

8.0

10.0

12.0

Difference, ppb

Max8hrO3 2002 Max8hrO3 2009 Max8hrO3 diff.

Fig. 7. Time-series of daily maximum 8-hour ozone

concentrations at the Conyers site based on 2002 and

2009 emissions.

The sensitivity analysis process was initiated

based on two assumptions: 1) projected 2009

controls alone would not be sufficient for

demonstrating attainment, as informally

demonstrated here; 2) barely attaining the

standard (i.e., a future DV of 84 ppb) might not

ensure long-term attainment (under more extreme

meteorological conditions), hence a “safety buffer”

should be considered, i.e. a future DV lower than

84 ppb would be preferable. A preliminary analysis

of the “safety buffer” for ensuring long-term

attainment suggests a buffer of 3-4 ppb at most

sites.

Testing attainment for PM2.5, even “informally”,

is not possible at present, as results for the winter

episode are not yet available (the PM2.5 standard

in an annual one, and all seasons need to be

represented). However, based on the results for

the summer episode, significant reductions in

sulfate levels (Figure 8, the average RRF for this

period is 0.7), and smaller reductions in elemental

carbon levels (Figure 9, the average RRF for this

period is 0.85) are observed.

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

5/25/025/27/025/29/025/31/02

6/2/02

6/4/026/6/026/8/02

6/10/026/12/02

6/14/026/16/026/18/026/20/026/22/026/24/02

ug/m3

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

Difference, ug/m3

SO4 2002 SO4 2009 SO4 diff.

Fig. 8. Time-series of daily-modeled sulfate

concentrations at the South-Dekalb site in Atlanta.

0.0

0.5

1.0

1.5

2.0

2.5

3.0

5/25/025/27/02

5/29/025/31/02

6/2/026/4/026/6/026/8/02

6/10/026/12/026/14/026/16/02

6/18/026/20/026/22/026/24/02

ug/m3

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

Difference, ug/m3

EC 2002 EC 2009 EC diff.

Fig. 9. Time-series of daily-modeled elemental-carbon

concentrations at the South-Dekalb site in Atlanta.

5. SENSITIVITY ANALYSIS

Regional sensitivities of ozone (ppb/ton per

day, TPD) and PM2.5 (μg/m

3

/TPD) include

responsiveness to 10% emission reductions in

anthropogenic, non-power plant NOx, VOCs, SO2,
4

NH3, and primary carbon PM2.5 in Atlanta, Macon,

Chattanooga, and Floyd County. Point source

sensitivities simulate the installation of SCRs

(NOx) and scrubbers (SO2) at the seven largest

coal-fired power plants in the state (Bowen,

Branch, Hammond, McDonough, Scherer,

Wansley, Yates).

5.1 Regional sensitivities

Here we present results for the sensitivities of

ozone and PM2.5 to regional reductions of

precursors (NOx, VOCs, SO2, primary carbon) in

both Atlanta (defined as the 20 non-attainment

counties) and Macon (Bibb, Crawford, Houston,

Jones, Monroe, Peach, and Twiggs counties).

Results from these sensitivities demonstrate that

the ozone chemistry in Atlanta is mainly NOx

limited (Figures 10-11). Very limited local

sensitivity to anthropogenic VOC emissions is

observed in the Atlanta urban core. This sensitivity

is higher on relatively low ozone days (such as

5/25/02, sensitivity of up to 0.8 ppb), likely due to

the lower biogenic VOC emissions on relatively

cooler days. However, such days are of low

importance in RRF calculations, as the ozone level

is below the threshold used for RRF calculations.

Sensitivities for emissions reductions in Macon

show similar patterns, with ozone being

completely NOx limited.

Fig. 10. Sensitivity of ozone (maximum 8-hour ozone

concentration, ppm) on 6/12/02 to a 10% reduction in

non-power plant NOx in the Atlanta area.

Fig. 11. Sensitivity of ozone (maximum 8-hour ozone

concentration, ppm) on 6/12/02 to a 10% reduction in

anthropogenic VOCs in the Atlanta area.

Sensitivity of PM2.5 to regional emissions

reductions is described here in terms of the

episode average change (future work will include

assigning specific weights to various modeled

days based on the CART analysis). Considering a

10% reduction in non-power plant emissions of

NOx, SO2, VOCs, NH3, and primary carbon (PC),

the reduction in PC had the greatest impact

(Figure 12). The impact due to PC emission

reductions is very local and corresponds to high

emissions in the core urban area (as opposed to

the more “regional” effect of SO2 reductions,

shown in Figure 13).

Fig. 12. Sensitivity of PM2.5 (average over entire

sensitivity episode) to a 10% reduction in non-power

plant primary carbon emissions in the Atlanta area.
5

Fig. 13. Sensitivity of PM2.5 (average over entire

sensitivity episode) to a 10% reduction in non-power

plant SO2 emissions in the Atlanta area.

To best summarize the impact of various

emissions reductions on ozone and PM2.5 levels

we scaled the maximum ozone reductions and

episode-average PM2.5 reductions based on the

actual tonnage reduction in emissions (Table 1).

These results further demonstrate the higher

efficiency of NOx controls compared to VOC for

ozone abatement in Atlanta and emphasize the

conceptual difference between controlling primary

and secondary PM2.5 components.

Ozone PM2.5

10%

change

in

maximum

reduction

(ppb)

reduction

per ton

(ppb/TPD)

episode

average

reduction

(μg/m

3

)

reduction

per ton

(μg/m

3

/TPD)

NOx 3.5 0.092 0.09 0.002

VOC 0.8 0.016 0.004 8E-05

SO2 - - 0.03 0.004

NH3 - - 0.08 0.01

carbon - - 0.45 0.22

Table 1. Per ton sensitivity (concentration/TPD) of

ozone and PM2.5 from a 10% reduction of non-power

plant emissions in the Atlanta area.

5.2 Point-source sensitivities

Point-source sensitivities simulated the

installation of scrubbers (for SO2 reductions) and

SCRs (for NOx reductions) in seven major power

plants in Georgia. Results were analyzed in terms

of reductions in both ozone and PM2.5. Simulating

the installation of a SCR to reduce NOx emissions

from plant McDonough, located in an Atlanta

suburb, shows reductions of up to 2 ppb in the

maximum 8-hour ozone concentration in Atlanta,

on a high ozone day (6/12/02, Figure 14). A similar

simulation for from plant Scherer, located

approximately 40 miles northwest of Macon,

resulted in reduction of approximately 4 ppb in the

maximum 8-hour ozone concentration in Macon,

on a high ozone day (6/3/02, Figure 15).

Fig. 14. Sensitivity of maximum 8-hour ozone

concentration on 6/12/02 to the installation of a SCR at

Plant McDonough.

Fig. 15. Sensitivity of maximum 8-hour ozone

concentration on 6/3/02 to the installation of a SCR at

Plant Scherer.

Sensitivities of PM2.5 concentrations to

installation of scrubbers and SCRs are presented

here in the form of the change in episode-average

concentrations. The impacts of an installation of a

scrubber and SCR in plant Scherer and a

scrubber in Plant Bowen (SCRs already installed)

(Figures 16, 17) are relatively large on an average

basis, considering that on many of the simulated

days a single monitor/cell may not be affected at

all by reductions in a specific plant (reflecting

different plume trajectories).
6

Fig. 16. Sensitivity of episode-average PM2.5

concentrations to the installation of a scrubber and SCR

at Plant Scherer.

Fig. 17. Sensitivity of episode-average PM2.5

concentrations to the installation of a scrubber at Plant

Bowen.

Scaling these modeled reductions in both

ozone and PM2.5 based on actual tonnage

reduction in precursor emissions (Table 2) can

serve to evaluate the effectiveness of such

reductions (especially when also combined with

population exposure).

6. DISCUSSION

Results presented here, along with a winter

episode sensitivity analysis which is in process,

and after further analysis to account for

meteorological bin frequencies and spatial

variability, will serve as the basis for evaluating

various control strategies for SIP development.

Results from this sensitivity analysis, in the form of

ppb/TPD or μg/m

3

/TPD will be linked with

economical considerations ($/ton) and with a

health/exposure analysis to develop the most costeffective and health-beneficial strategy for

attaining both the 8-hour ozone and annual PM2.5

standards .

Ozone PM2.5

Scrubber

and/or

SCR at

maximum

reduction

(ppb)

reduction

per ton

(ppb/TPD)

episode

average

reduction

(μg/m

3

)

reduction

per ton

(μg/m

3

/TPD)

Branch 5 0.33 0.36 0.0023

Bowen - - 0.42 0.0024

Hammond 5 0.45 0.30 0.0034

McDonough 1.5 0.21 0.18 0.0033

Scherer 6 0.20 0.66 0.0020

Wansley - - 0.31 0.0034

Yates 5 0.45 0.26 0.0028

Table 2. Per ton sensitivity (concentration/TPD) of

ozone and PM2.5 to reductions of SO2 and NOx from

major power plants in Georgia.