# 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 NO

x 

## 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 (NO

x 

### ) and volatile organic compounds

(VOCs). The analysis was based on the Vi sibility 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 repr esentative of longer te rm 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 outsi de 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 NO

x 

### controlled), SCRs on units 1&2 at Plant Wansley Heard County (51.7 TPD

NO

x 

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

Monroe County (24.2 TPD reduction in NO

x 

### 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 ar e the expected reductions in ozone

concentrations from potential ground-level NO

x 

### controls in the Atlanta 20-county NAA.

The purpose of this comparison is to evaluate the efficiency of NO

x 

### controls from outside

the Atlanta NAA and of VOC controls within the Atlanta NAA in te rms of reductions in

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

A-1

### ozone season) NO

x 

### controls outside of the Atla nta NAA overweigh any potential VOC

controls within the NAA.

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

Case 1: NO

x 

### reductions from SCRs installed and operated at GA-Power Plant Bowen

starting from the 2003 ozone season (units 3&4; 61.1 TPD NO

x 

### controlled

compared to the pre-installation/operation conditions).

Case 2: NO

x 

### reductions from SCRs installed a nd operated at GA-Power Plant Wansley

starting from the 2003 ozone season (units 1&2; 51.7 TPD NO

x 

### controlled

compared to the pre-installation/operation conditions).

Case 3: NO

x 

### reductions from the switch to PRB co al at GA-Power Plant Scherer; 24.2

TPD reduction in NO

x 

### 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 an thropogenic, 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 NO

x



### 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 (NO

x 

### )

2 Wansley units 1&2 (benefits of existing SCRs) 51.7 (NO

x 

### )

3 Scherer (use of PRB coal) 24.2 (NO

x 

### )

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

5 10% anthropogenic NO

x 

### controls in the Atlanta NAA 38.0 (NO

x 

### )

Results

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

along with the modeled base-case concentr ations (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 /2

5 5/27

5 /2

9 5/31 6 / 2 6/4 6 /6 6/8

6 /1

0

6 / 12

6 /1

4

6 / 16

6 /1

8

6 / 20

6 /2

2

6 / 24

DateReduction in max 8-hr O3(ppb)

20 30 40 50 60 70 80 90 100 110 120Max 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 A tlanta Confederate Avenue site. Green rectangles indicate

days in which the 2002 base case daily 8hr maximum ozone concentr ation 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 co ncentrations at the Atlanta Confederate

Avenue site, with reductions of up to 2.9 ppb. Also evident are the impacts of NO

x



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

controlling ground level NO

x 

### 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 scenar ios modeled here differ in

magnitude (TPD controlled), we also normaliz ed the reductions in oz one to the tons of

NO

x 

### or VOC controlled. The average and norma lized 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 whic h 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 NO

x



### 2 0.39 7.6 ppt O3 / TPD NO

x



### 3 0.21 8.6 ppt O3 / TPD NO

x



### 1+2+3 1.4 10.0 ppt O3 / TPD NO

x



### 4 0.30 6.0 ppt O3 / TPD VOC

5 1.2 31.4 ppt O3 / TPD NO

x



### 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 (1 2.8, 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 NO

x



### emissions in the Atlanta NAA (Cas e 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 NO

x 

### emissions reductions expected by 2009,

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

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

ongoing reductions in NO

x 

### 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 PM 2.5



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

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

included as Appendix A Exhibit 1, below.

A-5

### Appendix A Exhibit 1

8-Hour Ozone and PM2.5 Modeli ng to Support the Georgia SIP1



### 8

- H O U R O Z O N E A N D P M 2

. 5 

### M O D E L I N G T O S U P P O R T T H E G E O R G I A S I P

A m i t M a r m u r *

, J a m e s B o y l a n

, M a u d o o d K h a n

, a n d D a n i e l C o h a n

E n v i r o n m e n t a l P r o t e c t i o n D i v i s i o n

, G e o r g i a D e p a r t m e n t o f N a t u r a l R e s o u r c e s

, A t l a n t a

, G A

, U S A



### 1

. I N T R O D U C T I O N

W i t h t h e o n s e t o f t h e n e w N a t i o n a l A m b i e n t A i r

Q u a l i t y S t a n d a r d s ( N A A Q S ) f o r o z o n e a n d f i n e

p a r t i c u l a t e m a t t e r ( P M 2

. 5 )

, G e o r g i a n o w c o n f r o n t s

n o n a t t a i n m e n t f o r m u l t i p l e p o l l u t a n t s a n d r e g i o n s

. W h i l e 1 3 A t l a n t a c o u n t i e s h a d h i s t o r i c a l l y v i o l a t e d

t h e n o w

- r e v o k e d 1

- h o u r s t a n d a r d f o r o z o n e o f

0

. 1 2 p p m ( b e l o w 1 2 5 p p b )

, a l a r g e r A t l a n t a r e g i o n

( F i g u r e 1 )

, a l o n g w i t h M a c o n

, v i o l a t e t h e n e w 8

-

h o u r s t a n d a r d o f 0

. 0 8 p p m ( b e l o w 8 5 p p b )

. A l s o

,

a n e a r l y a c t i o n c o m p a c t ( E A C ) h a s b e e n

d e v e l o p e d t o r e d u c e o z o n e i n C h a t t a n o o g a a n d

A u g u s t a

. A t l a n t a

, M a c o n

, F l o y d C o u n t y

, a n d

C h a t t a n o o g a ( F i g u r e 2 ) v i o l a t e t h e a n n u a l P M 2

. 5

s t a n d a r d ( 1 5 μ g / m 3 )

, m a r k i n g t h e f i r s t t i m e t h a t

G e o r g i a m u s t d e v e l o p s t a t e i m p l e m e n t a t i o n p l a n s

( S I P s ) t o c o n t r o l p a r t i c u l a t e m a t t e r

. S I P s

d e m o n s t r a t i n g p l a n s o f a c t i o n f o r f u t u r e a t t a i n m e n t

a r e d u e i n 2 0 0 7 f o r o z o n e a n d i n 2 0 0 8 f o r P M 2

. 5

. T h e s e p l a n s w i l l d e t a i l l o c a l c o n t r o l m e a s u r e s t o

c o m p l e m e n t e x p e c t e d e m i s s i o n s r e d u c t i o n s f r o m

f e d e r a l a c t i o n s

, i n c l u d i n g t h e C l e a n A i r I n t e r s t a t e

R u l e f o r p o w e r p l a n t s a n d m o r e s t r i n g e n t f e d e r a l

s t a n d a r d s f o r v e h i c l e s

, f u e l s

, a n d n o n

- r o a d

e q u i p m e n t

.

F i g

. 1

. G e o r g i a 8

- h o u r o z o n e n o n

- a t t a i n m e n t a r e a s

( C h a t t a n o o g a i s a n E A C a r e a )

.

* C o r r e s p o n d i n g a u t h o r : A m i t M a r m u r

, E n v i r o n m e n t a l

P r o t e c t i o n D i v i s i o n

, G e o r g i a D e p a r t m e n t o f N a t u r a l

R e s o u r c e s

, 4 2 4 4 I n t e r n a t i o n a l P a r k w a y

, S u i t e 1 2 0

, A t l a n t a

, G A 3 0 3 5 4 ; e

- m a i l :

a m i t

_ m a r m u r @ d n r

. s t a t e

. g a

. u s F i g

. 2

. G e o r g i a a n n u a l P M 2

. 5 n o n

- a t t a i n m e n t a r e a s

.



### 2

. M O D E L I N G S Y S T E M A N D G R I D

C O N F I G U R A T I O N

I n o r d e r t o e v a l u a t e a n d d e v e l o p e f f i c i e n t

e m i s s i o n c o n t r o l s t r a t e g i e s a n d d e m o n s t r a t e f u t u r e

a t t a i n m e n t w i t h t h e N A A Q S

, t h e G e o r g i a

E n v i r o n m e n t a l P r o t e c t i o n D i v i s i o n ( G A E P D ) i s

u s i n g t h e M M 5 / S M O K E / C M A Q m o d e l i n g s y s t e m

. T h e m o d e l i n g u s e d i n t h e s e S I P a t t a i n m e n t

d e m o n s t r a t i o n s i s b a s e d o n t h e V I S T A S r e g i o n a l

h a z e m o d e l i n g w h i c h i n c l u d e s a n n u a l s i m u l a t i o n s

o f 2 0 0 2

, 2 0 0 9

, a n d 2 0 1 8 a t 3 6 k m ( c o n t i n e n t a l

U

. S

. ) a n d 1 2 k m ( E a s t e r n U

. S

. ) g r i d r e s o l u t i o n s

. I n a d d i t i o n

, G A E P D h a s d e v e l o p e d a s m a l l e r 1 2

k m g r i d ( r e f e r r e d t o a s A L G A 1 2 ) t h a t c o v e r s

G e o r g i a a n d A l a b a m a ( a n d t h e i r a d j a c e n t s t a t e s )

a n d a 4

- k m g r i d o v e r G e o r g i a ( r e f e r r e d t o a s G A 4 )

. W h i l e a n n u a l P M 2

. 5 m o d e l i n g s i m u l a t i o n s w i l l b e

c o n d u c t e d o n t h e A L G A 1 2 g r i d

, o n l y 4 m o n t h s o f

t h e 2 0 0 2 o z o n e s e a s o n ( 0 5 / 2 0 / 0 2

- 0 9 / 2 0 / 0 2 ) w i l l

b e s i m u l a t e d o n t h e m o r e r e f i n e d G A 4 g r i d



### 3

. E P I S O D E S E L E C T I O N

I n o r d e r t o m o s t e f f i c i e n t l y d e s i g n e m i s s i o n

c o n t r o l s t r a t e g i e s t o r e d u c e P M 2

. 5 a n d o z o n e

, G A

E P D i s p e r f o r m i n g e p i s o d i c e m i s s i o n s e n s i t i v i t i e s

o n a w i n t e r ( 1 1 / 1 9 / 0 2

- 1 2 / 1 9 / 0 2 ) a n d a s u m m e r

e p i s o d e ( 0 5 / 2 5 / 0 2

- 0 6 / 2 5 / 0 2 )

. T o o b j e c t i v e l y s e l e c t

r e p r e s e n t a t i v e t i m e p e r i o d s f o r s e n s i t i v i t y

s i m u l a t i o n s

, G A E P D s e l e c t e d t h e a b o v e e p i s o d e s

b a s e d o n a c l a s s i f i c a t i o n a n d r e g r e s s i o n t r e e

( C A R T ) a n a l y s i s

. C A R T a n a l y s i s e x a m i n e s2

h i s t o r i c a l r e c o r d s o f m e t e o r o l o g y a n d p o l l u t a n t

c o n c e n t r a t i o n s t o i d e n t i f y “ b i n s ” o f d a y s w i t h

s i m i l a r c o n d i t i o n s

. E p i s o d e s a r e t h e n s e l e c t e d t o

c a p t u r e a s p e c t r u m o f r e p r e s e n t a t i v e c o n d i t i o n s

. F o r o z o n e

, w h i c h i s s u b j e c t t o a s t a n d a r d b a s e d

o n p e a k d a y s

, a o n e

- m o n t h s u m m e r t i m e e p i s o d e

w a s s e l e c t e d t h a t i n c l u d e d a l l “ k e y b i n s ” o f m o s t

t y p i c a l p o l l u t e d c o n d i t i o n s

. F o r P M 2

. 5 , w h i c h i s

s u b j e c t t o a n a n n u a l a v e r a g e s t a n d a r d

, t h e

s u m m e r e p i s o d e w a s p a i r e d w i t h a o n e

- m o n t h

w i n t e r e p i s o d e t o c a p t u r e a b r o a d r a n g e o f b o t h

p o l l u t e d a n d r e l a t i v e l y c l e a n c o n d i t i o n s

. T h e s e

e p i s o d e s w e r e s e l e c t e d b a s e d o n a C A R T

a n a l y s i s t o e n s u r e t h a t a v a r i e t y o f m e t e o r o l o g i c a l

c o n d i t i o n s i m p o r t a n t t o P M 2

. 5 a n d o z o n e f o r m a t i o n

w e r e s i m u l a t e d

. A h i s t o g r a m c o m p a r i n g f r e q u e n c y

o f o c c u r r e n c e o f k e y h i g h o z o n e b i n s d u r i n g t h e

e n t i r e e i g h t

- y e a r p e r i o d ( 1 9 9 6

- 2 0 0 3 )

, t h e y e a r

2 0 0 2

, a n d t h e c h o s e n s u m m e r e p i s o d e ( 0 5 / 2 5 / 0 2

-

0 6 / 2 5 / 0 2 ) ( F i g u r e 3 ) s h o w s t h a t t h i s e p i s o d e

r e p r e s e n t s a l l k e y o z o n e c o n d u c i v e m e t e o r o l o g i c a l

c o n d i t i o n s i n A t l a n t a

. U n d e r / o v e r r e p r e s e n t a t i o n o f

s p e c i f i c b i n s ( e

. g

. , b i n 2 1 ) c a n b e c o r r e c t e d b y

a s s i g n i n g w e i g h t s t o t h e d i f f e r e n t b i n s

. A s i m i l a r

h i s t o g r a m f o r P M 2

. 5 ( F i g u r e 4 )

, c o v e r i n g b o t h

s u m m e r a n d w i n t e r e p i s o d e s

, s h o w s t h a t m o s t k e y

P M 2

. 5 b i n s a r e c a p t u r e d a s w e l l

.

O z o n e K e y B i n F r e q u e n c y f o r A t l a n t a

0 1 2 3 4 5 6 7 8

2 6 1 4 9 1 6 2 1PercentContribution

A l l Y e a r s 2 0 0 2 G A E p i s o d e

F i g

. 3

. F r e q u e n c y o f C A R T b i n s f o r o z o n e f o r t h e p e r i o d

1 9 9 6

- 2 0 0 3

, t h e y e a r 2 0 0 2

, a n d t h e s e l e c t e d e p i s o d e

.

P M 2

. 5 B i n F r e q u e n c y f o r A t l a n t a

0 1 0 2 0 3 0 4 0 5 0

1 4 3 1 6 1 0 2 8 5 2 0 7 3 5 3 1 3 6 2 6 1 9 1 1 1 5 1 8 2 2 2 3 2 4PercentContribution

A l l Y e a r s 2 0 0 2 G A E p i s o d e s

F i g

. 4

. F r e q u e n c y o f C A R T b i n s f o r P M 2

. 5 f o r t h e p e r i o d

2 0 0 0

- 2 0 0 3

, t h e y e a r 2 0 0 2

, a n d t h e s e l e c t e d

e p i s o d e s

. 

### 4

. P R O J E C T E D E M I S S I O N S R E D U C T I O N S

B Y 2 0 0 9 A N D T H E I R E F F E C T O N O Z O N E

A N D P M 2

. 5 

### L E V E L S

S i n c e G e o r g i a ’ s a t t a i n m e n t s t a t u s w i l l b e

e v a l u a t e d i n 2 0 1 0

, s e n s i t i v i t y r u n s a r e c o n d u c t e d

u s i n g t h e V I S T A S 2 0 0 9 e m i s s i o n s i n v e n t o r y

. T h e

f o l l o w i n g i s a p r e l i m i n a r y a n a l y s i s o f t h e i m p a c t o f

p r o j e c t e d r e g i o n a l r e d u c t i o n s i n e m i s s i o n s ( 2 0 0 9

i n v e n t o r y c o m p a r e d t o 2 0 0 2 ) o n o z o n e a n d P M 2

. 5

c o n c e n t r a t i o n s

.



### 4

. 1 P r o j e c t e d E m i s s i o n s R

e d u c t i o n s b y

2 0 0 9 c o m

p a r e d t o 2 0 0

2

C o m p a r i n g t h e G e o r g i a 2 0 0 2 a n d 2 0 0 9

i n v e n t o r i e s ( F i g u r e 5 )

, r e d u c t i o n s o f 2 4 %

, 3 4 %

a n d 1 4 % a r e o b s e r v e d f o r N O

x , S O 2 a n d V O C s

,

r e s p e c t i v e l y

.

0 1 0 0 2 0 0 3 0 0 4 0 0 5 0 0 6 0 0 7 0 0 8 0 0

N O x

2 0 0 2 N O x

2 0 0 9 S O 2

2 0 0 2 S O 2

2 0 0 9 V O C

2 0 0 2 V O C

2 0 0 9ThousandTons A r e a

( V O C o n l y )

P o i n t

( V O C o n l y )

M i s c

.

I n d u s t r i a l

O t h e r F u e l

C o m b u s t

.

E G U

N o n R o a d

O n R o a d

F i g

. 5

. C o m p a r i s o n b e t w e e n t h e 2 0 0 2 a n d 2 0 0 9 G e o r g i a

E m i s s i o n s I n v e n t o r y



### 4

. 2 R e d u c t i o n s i n o z o n e a n d P

M 2

. 5 

### b a s e d o n t

h e 2 0 0 9 i

n v e n t o r y

T h e f o l l o w i n g i s a p r e l i m i n a r y a n a l y s i s o f

r e d u c t i o n s i n o z o n e a n d P M 2

. 5 f r o m c o n t r o l s

a l r e a d y i n t h e p r o c e s s o f b e i n g i m p l e m e n t e d ( a s

s h o w n i n F i g u r e 5 )

. T i m e

- s e r i e s p l o t s f o r o z o n e u s i n g t h e 2 0 0 2

a n d 2 0 0 9 i n v e n t o r i e s f o r a c e n t r a l A t l a n t a s i t e

( C o n f e d e r a t e A v e n u e

, F i g u r e 6 ) a n d a s u b u r b a n

d o w n w i n d s i t e ( C o n y e r s

, F i g u r e 7 ) s h o w

r e d u c t i o n s o f u p t o 1 2 p p b i n t h e d a i l y m a x i m u m 8

-

h o u r o z o n e c o n c e n t r a t i o n

. U s i n g t h e s e s i m u l a t e d

v a l u e s f o r t h e s e n s i t i v i t y e p i s o d e o f 5 / 2 5 / 0 2

-

6 / 2 5 / 0 2 a n d a c u t o f f v a l u e o f 7 5 p p b

, R e l a t i v e

R e d u c t i o n F a c t o r s ( R R F

, t h e r a t i o b e t w e e n3

c o n t r o l l e d a n d u n c o n t r o l l e d c a s e c o n c e n t r a t i o n s )

w e r e c a l c u l a t e d f o r t h e s e s i t e s

, a n d r e s u l t e d i n a

R R F o f 0

. 9

. W h e n t h e s e r a t i o s a r e a p p l i e d t o t h e

D e s i g n V a l u e s ( D V

, w e i g h t e d a v e r a g e o f t h e f o r t h

h i g h e s t 8

- h o u r o z o n e c o n c e n t r a t i o n o v e r a f i v e

y e a r p e r i o d c e n t e r e d a r o u n d t h e m o d e l i n g y e a r ) a t

e a c h s i t e

, a f u t u r e ( 2 0 0 9 ) D V i s o b t a i n e d

. I n t h e

p r e l i m i n a r y a n a l y s i s c o n d u c t e d h e r e ( a c c o u n t i n g

f o r o n l y o n e m o n t h o f m o d e l i n g a n d o n l y t w o

s p e c i f i c s i t e s / g i r d

- c e l l s )

, t h e f u t u r e D V s o b t a i n e d

a r e 8 6 p p b ( 0

. 9 x 9 5 p p b

, t h e D V f o r 2 0 0 2 ) f o r t h e

C o n f e d e r a t e A v e n u e s i t e a n d 8 2 ( 0

. 9 x 9 1 p p b

, t h e

D V f o r 2 0 0 2 ) f o r t h e C o n y e r s s i t e

. B a s e d o n t h i s

p r e l i m i n a r y a n d “ i n f o r m a l ” a n a l y s i s

, i t w o u l d s e e m

t h a t t h e C o n f e d e r a t e A v e n u e s i t e w o u l d n o t a t t a i n

t h e s t a n d a r d ( > 8 5 p p b )

, w h i l e t h e C o n y e r s s i t e

w o u l d a t t a i n ( < 8 5 p p b )

.

0 2 0 4 0 6 0 8 0 1 0 0 1 2 0 1 4 05/25/025/27/025/29/025/31/026/2/026/4/026/6/026/8/026/10/026/12/026/14/026/16/026/18/026/20/026/22/026/24/02ppb

- 2

. 0 0

. 0 2

. 0 4

. 0 6

. 0 8

. 0 1 0

. 0 1 2

. 0Difference,ppb

M a x 8 h r O 3 2 0 0 2 M a x 8 h r O 3 2 0 0 9 M a x 8 h r O 3 d i f f

.

F i g

. 6

. T i m e

- s e r i e s o f m o d e l e d d a i l y m a x i m u m 8

- h o u r

o z o n e c o n c e n t r a t i o n s a t t h e C o n f e d e r a t e A v e n u e

( A t l a n t a ) s i t e b a s e d o n 2 0 0 2 a n d 2 0 0 9 e m i s s i o n s

.

0 2 0 4 0 6 0 8 0 1 0 0 1 2 05/25/025/27/025/29/025/31/026/2/026/4/026/6/026/8/026/10/026/12/026/14/026/16/026/18/026/20/026/22/026/24/02ppb

0

. 0 2

. 0 4

. 0 6

. 0 8

. 0 1 0

. 0 1 2

. 0Difference,ppb

M a x 8 h r O 3 2 0 0 2 M a x 8 h r O 3 2 0 0 9 M a x 8 h r O 3 d i f f

.

F i g

. 7

. T i m e

- s e r i e s o f d a i l y m a x i m u m 8

- h o u r o z o n e

c o n c e n t r a t i o n s a t t h e C o n y e r s s i t e b a s e d o n 2 0 0 2 a n d

2 0 0 9 e m i s s i o n s

.

T h e s e n s i t i v i t y a n a l y s i s p r o c e s s w a s i n i t i a t e d

b a s e d o n t w o a s s u m p t i o n s : 1 ) p r o j e c t e d 2 0 0 9

c o n t r o l s a l o n e w o u l d n o t b e s u f f i c i e n t f o r

d e m o n s t r a t i n g a t t a i n m e n t

, a s i n f o r m a l l y

d e m o n s t r a t e d h e r e ; 2 ) b a r e l y a t t a i n i n g t h e

s t a n d a r d ( i

. e

. , a f u t u r e D V o f 8 4 p p b ) m i g h t n o t e n s u r e l o n g

- t e r m a t t a i n m e n t ( u n d e r m o r e e x t r e m e

m e t e o r o l o g i c a l c o n d i t i o n s )

, h e n c e a “ s a f e t y b u f f e r ”

s h o u l d b e c o n s i d e r e d

, i

. e

. a f u t u r e D V l o w e r t h a n

8 4 p p b w o u l d b e p r e f e r a b l e

. A p r e l i m i n a r y a n a l y s i s

o f t h e “ s a f e t y b u f f e r ” f o r e n s u r i n g l o n g

- t e r m

a t t a i n m e n t s u g g e s t s a b u f f e r o f 3

- 4 p p b a t m o s t

s i t e s

. T e s t i n g a t t a i n m e n t f o r P M 2

. 5 , e v e n “ i n f o r m a l l y ”

, i s n o t p o s s i b l e a t p r e s e n t

, a s r e s u l t s f o r t h e w i n t e r

e p i s o d e a r e n o t y e t a v a i l a b l e ( t h e P M 2

. 5 s t a n d a r d

i n a n a n n u a l o n e

, a n d a l l s e a s o n s n e e d t o b e

r e p r e s e n t e d )

. H o w e v e r

, b a s e d o n t h e r e s u l t s f o r

t h e s u m m e r e p i s o d e

, s i g n i f i c a n t r e d u c t i o n s i n

s u l f a t e l e v e l s ( F i g u r e 8

, t h e a v e r a g e R R F f o r t h i s

p e r i o d i s 0

. 7 )

, a n d s m a l l e r r e d u c t i o n s i n e l e m e n t a l

c a r b o n l e v e l s ( F i g u r e 9

, t h e a v e r a g e R R F f o r t h i s

p e r i o d i s 0

. 8 5 ) a r e o b s e r v e d

.

0

. 0 2

. 0 4

. 0 6

. 0 8

. 0 1 0

. 0 1 2

. 0 1 4

. 0 1 6

. 05/25/025/27/025/29/025/31/026/2/026/4/026/6/026/8/026/10/026/12/026/14/026/16/026/18/026/20/026/22/026/24/02ug/m3

0

. 0 1

. 0 2

. 0 3

. 0 4

. 0 5

. 0 6

. 0 7

. 0 8

. 0Difference,ug/m3

S O 4 2 0 0 2 S O 4 2 0 0 9 S O 4 d i f f

.

F i g

. 8

. T i m e

- s e r i e s o f d a i l y

- m o d e l e d s u l f a t e

c o n c e n t r a t i o n s a t t h e S o u t h

- D e k a l b s i t e i n A t l a n t a

.

0

. 0 0

. 5 1

. 0 1

. 5 2

. 0 2

. 5 3

. 05/25/025/27/025/29/025/31/026/2/026/4/026/6/026/8/026/10/026/12/026/14/026/16/026/18/026/20/026/22/026/24/02ug/m3

- 0

. 0 5 0

. 0 0 0

. 0 5 0

. 1 0 0

. 1 5 0

. 2 0 0

. 2 5Difference,ug/m3

E C 2 0 0 2 E C 2 0 0 9 E C d i f f

.

F i g

. 9

. T i m e

- s e r i e s o f d a i l y

- m o d e l e d e l e m e n t a l

- c a r b o n

c o n c e n t r a t i o n s a t t h e S o u t h

- D e k a l b s i t e i n A t l a n t a

.



### 5

. S E N S I T I V I T Y A N A L Y S I S

R e g i o n a l s e n s i t i v i t i e s o f o z o n e ( p p b / t o n p e r

d a y

, T P D ) a n d P M 2

. 5 ( μ g / m 3 / T P D ) i n c l u d e

r e s p o n s i v e n e s s t o 1 0 % e m i s s i o n r e d u c t i o n s i n

a n t h r o p o g e n i c

, n o n

- p o w e r p l a n t N O

x , V O C s

, S O 2 ,4

N H 3 , a n d p r i m a r y c a r b o n P M 2

. 5 i n A t l a n t a

, M a c o n

, C h a t t a n o o g a

, a n d F l o y d C o u n t y

. P o i n t s o u r c e

s e n s i t i v i t i e s s i m u l a t e t h e i n s t a l l a t i o n o f S C R s

( N O

x ) a n d s c r u b b e r s ( S O 2 ) a t t h e s e v e n l a r g e s t

c o a l

- f i r e d p o w e r p l a n t s i n t h e s t a t e ( B o w e n

, B r a n c h

, H a m m o n d

, M c D o n o u g h

, S c h e r e r

, W a n s l e y

, Y a t e s )

.



### 5

. 1 R e g i o n a l s e n s i t

i v i t i e s

H e r e w e p r e s e n t r e s u l t s f o r t h e s e n s i t i v i t i e s o f

o z o n e a n d P M 2

. 5 t o r e g i o n a l r e d u c t i o n s o f

p r e c u r s o r s ( N O

x , V O C s

, S O 2 , p r i m a r y c a r b o n ) i n

b o t h A t l a n t a ( d e f i n e d a s t h e 2 0 n o n

- a t t a i n m e n t

c o u n t i e s ) a n d M a c o n ( B i b b

, C r a w f o r d

, H o u s t o n

, J o n e s

, M o n r o e

, P e a c h

, a n d T w i g g s c o u n t i e s )

. R e s u l t s f r o m t h e s e s e n s i t i v i t i e s d e m o n s t r a t e t h a t

t h e o z o n e c h e m i s t r y i n A t l a n t a i s m a i n l y N O

x l i m i t e d ( F i g u r e s 1 0

- 1 1 )

. V e r y l i m i t e d l o c a l

s e n s i t i v i t y t o a n t h r o p o g e n i c V O C e m i s s i o n s i s

o b s e r v e d i n t h e A t l a n t a u r b a n c o r e

. T h i s s e n s i t i v i t y

i s h i g h e r o n r e l a t i v e l y l o w o z o n e d a y s ( s u c h a s

5 / 2 5 / 0 2

, s e n s i t i v i t y o f u p t o 0

. 8 p p b )

, l i k e l y d u e t o

t h e l o w e r b i o g e n i c V O C e m i s s i o n s o n r e l a t i v e l y

c o o l e r d a y s

. H o w e v e r

, s u c h d a y s a r e o f l o w

i m p o r t a n c e i n R R F c a l c u l a t i o n s

, a s t h e o z o n e l e v e l

i s b e l o w t h e t h r e s h o l d u s e d f o r R R F c a l c u l a t i o n s

. S e n s i t i v i t i e s f o r e m i s s i o n s r e d u c t i o n s i n M a c o n

s h o w s i m i l a r p a t t e r n s

, w i t h o z o n e b e i n g

c o m p l e t e l y N O

x l i m i t e d

.

F i g

. 1 0

. S e n s i t i v i t y o f o z o n e ( m a x i m u m 8

- h o u r o z o n e

c o n c e n t r a t i o n

, p p m ) o n 6 / 1 2 / 0 2 t o a 1 0 % r e d u c t i o n i n

n o n

- p o w e r p l a n t N O

x i n t h e A t l a n t a a r e a

. F i g

. 1 1

. S e n s i t i v i t y o f o z o n e ( m a x i m u m 8

- h o u r o z o n e

c o n c e n t r a t i o n

, p p m ) o n 6 / 1 2 / 0 2 t o a 1 0 % r e d u c t i o n i n

a n t h r o p o g e n i c V O C s i n t h e A t l a n t a a r e a

.

S e n s i t i v i t y o f P M 2

. 5 t o r e g i o n a l e m i s s i o n s

r e d u c t i o n s i s d e s c r i b e d h e r e i n t e r m s o f t h e

e p i s o d e a v e r a g e c h a n g e ( f u t u r e w o r k w i l l i n c l u d e

a s s i g n i n g s p e c i f i c w e i g h t s t o v a r i o u s m o d e l e d

d a y s b a s e d o n t h e C A R T a n a l y s i s )

. C o n s i d e r i n g a

1 0 % r e d u c t i o n i n n o n

- p o w e r p l a n t e m i s s i o n s o f

N O

x , S O 2 , V O C s

, N H 3 , a n d p r i m a r y c a r b o n ( P C )

, t h e r e d u c t i o n i n P C h a d t h e g r e a t e s t i m p a c t

( F i g u r e 1 2 )

. T h e i m p a c t d u e t o P C e m i s s i o n

r e d u c t i o n s i s v e r y l o c a l a n d c o r r e s p o n d s t o h i g h

e m i s s i o n s i n t h e c o r e u r b a n a r e a ( a s o p p o s e d t o

t h e m o r e “ r e g i o n a l ” e f f e c t o f S O 2 r e d u c t i o n s

,

s h o w n i n F i g u r e 1 3 )

.

F i g

. 1 2

. S e n s i t i v i t y o f P M 2

. 5 ( a v e r a g e o v e r e n t i r e

s e n s i t i v i t y e p i s o d e ) t o a 1 0 % r e d u c t i o n i n n o n

- p o w e r

p l a n t p r i m a r y c a r b o n e m i s s i o n s i n t h e A t l a n t a a r e a

.5

F i g

. 1 3

. S e n s i t i v i t y o f P M 2

. 5 ( a v e r a g e o v e r e n t i r e

s e n s i t i v i t y e p i s o d e ) t o a 1 0 % r e d u c t i o n i n n o n

- p o w e r

p l a n t S O 2 e m i s s i o n s i n t h e A t l a n t a a r e a

.

T o b e s t s u m m a r i z e t h e i m p a c t o f v a r i o u s

e m i s s i o n s r e d u c t i o n s o n o z o n e a n d P M 2

. 5 l e v e l s

w e s c a l e d t h e m a x i m u m o z o n e r e d u c t i o n s a n d

e p i s o d e

- a v e r a g e P M 2

. 5 r e d u c t i o n s b a s e d o n t h e

a c t u a l t o n n a g e r e d u c t i o n i n e m i s s i o n s ( T a b l e 1 )

. T h e s e r e s u l t s f u r t h e r d e m o n s t r a t e t h e h i g h e r

e f f i c i e n c y o f N O

x c o n t r o l s c o m p a r e d t o V O C f o r

o z o n e a b a t e m e n t i n A t l a n t a a n d e m p h a s i z e t h e

c o n c e p t u a l d i f f e r e n c e b e t w e e n c o n t r o l l i n g p r i m a r y

a n d s e c o n d a r y P M 2

. 5 c o m p o n e n t s

.

O z o n e P M 2

. 5

1 0 %

c h a n g e

i n m a x i m u m

r e d u c t i o n

( p p b ) r e d u c t i o n

p e r t o n

( p p b / T P D ) e p i s o d e

a v e r a g e

r e d u c t i o n

( μ g / m 3 ) r e d u c t i o n

p e r t o n

( μ g / m 3 / T P D )

N O

x 3

. 5 0

. 0 9 2 0

. 0 9 0

. 0 0 2

V O C 0

. 8 0

. 0 1 6 0

. 0 0 4 8 E

- 0 5

S O 2 - - 0

. 0 3 0

. 0 0 4

N H 3 - - 0

. 0 8 0

. 0 1

c a r b o n

- - 0

. 4 5 0

. 2 2

T a b l e 1

. P e r t o n s e n s i t i v i t y ( c o n c e n t r a t i o n / T P D ) o f

o z o n e a n d P M 2

. 5 f r o m a 1 0 % r e d u c t i o n o f n o n

- p o w e r

p l a n t e m i s s i o n s i n t h e A t l a n t a a r e a

.



### 5

. 2 P o i n t

- s o u r c e s e n s i t

i v i t i e s

P o i n t

- s o u r c e s e n s i t i v i t i e s s i m u l a t e d t h e

i n s t a l l a t i o n o f s c r u b b e r s ( f o r S O 2 r e d u c t i o n s ) a n d

S C R s ( f o r N O

x r e d u c t i o n s ) i n s e v e n m a j o r p o w e r

p l a n t s i n G e o r g i a

. R e s u l t s w e r e a n a l y z e d i n t e r m s

o f r e d u c t i o n s i n b o t h o z o n e a n d P M 2

. 5

. S i m u l a t i n g

t h e i n s t a l l a t i o n o f a S C R t o r e d u c e N O

x e m i s s i o n s

f r o m p l a n t M c D o n o u g h

, l o c a t e d i n a n A t l a n t a

s u b u r b

, s h o w s r e d u c t i o n s o f u p t o 2 p p b i n t h e

m a x i m u m 8

- h o u r o z o n e c o n c e n t r a t i o n i n A t l a n t a

,

o n a h i g h o z o n e d a y ( 6 / 1 2 / 0 2

, F i g u r e 1 4 )

. A s i m i l a r

s i m u l a t i o n f o r f r o m p l a n t S c h e r e r

, l o c a t e d

a p p r o x i m a t e l y 4 0 m i l e s n o r t h w e s t o f M a c o n

, r e s u l t e d i n r e d u c t i o n o f a p p r o x i m a t e l y 4 p p b i n t h e

m a x i m u m 8

- h o u r o z o n e c o n c e n t r a t i o n i n M a c o n

,

o n a h i g h o z o n e d a y ( 6 / 3 / 0 2

, F i g u r e 1 5 )

.

F i g

. 1 4

. S e n s i t i v i t y o f m a x i m u m 8

- h o u r o z o n e

c o n c e n t r a t i o n o n 6 / 1 2 / 0 2 t o t h e i n s t a l l a t i o n o f a S C R a t

P l a n t M c D o n o u g h

.

F i g

. 1 5

. S e n s i t i v i t y o f m a x i m u m 8

- h o u r o z o n e

c o n c e n t r a t i o n o n 6 / 3 / 0 2 t o t h e i n s t a l l a t i o n o f a S C R a t

P l a n t S c h e r e r

.

S e n s i t i v i t i e s o f P M 2

. 5 c o n c e n t r a t i o n s t o

i n s t a l l a t i o n o f s c r u b b e r s a n d S C R s a r e p r e s e n t e d

h e r e i n t h e f o r m o f t h e c h a n g e i n e p i s o d e

- a v e r a g e

c o n c e n t r a t i o n s

. T h e i m p a c t s o f a n i n s t a l l a t i o n o f a

s c r u b b e r a n d S C R i n p l a n t S c h e r e r a n d a

s c r u b b e r i n P l a n t B o w e n ( S C R s a l r e a d y i n s t a l l e d )

( F i g u r e s 1 6

, 1 7 ) a r e r e l a t i v e l y l a r g e o n a n a v e r a g e

b a s i s

, c o n s i d e r i n g t h a t o n m a n y o f t h e s i m u l a t e d

d a y s a s i n g l e m o n i t o r / c e l l m a y n o t b e a f f e c t e d a t

a l l b y r e d u c t i o n s i n a s p e c i f i c p l a n t ( r e f l e c t i n g

d i f f e r e n t p l u m e t r a j e c t o r i e s )

.6

F i g

. 1 6

. S e n s i t i v i t y o f e p i s o d e

- a v e r a g e P M 2

. 5

c o n c e n t r a t i o n s t o t h e i n s t a l l a t i o n o f a s c r u b b e r a n d S C R

a t P l a n t S c h e r e r

.

F i g

. 1 7

. S e n s i t i v i t y o f e p i s o d e

- a v e r a g e P M 2

. 5

c o n c e n t r a t i o n s t o t h e i n s t a l l a t i o n o f a s c r u b b e r a t P l a n t

B o w e n

.

S c a l i n g t h e s e m o d e l e d r e d u c t i o n s i n b o t h

o z o n e a n d P M 2

. 5 b a s e d o n a c t u a l t o n n a g e

r e d u c t i o n i n p r e c u r s o r e m i s s i o n s ( T a b l e 2 ) c a n

s e r v e t o e v a l u a t e t h e e f f e c t i v e n e s s o f s u c h

r e d u c t i o n s ( e s p e c i a l l y w h e n a l s o c o m b i n e d w i t h

p o p u l a t i o n e x p o s u r e )

.



### 6

. D I S C U S S I O N

R e s u l t s p r e s e n t e d h e r e

, a l o n g w i t h a w i n t e r

e p i s o d e s e n s i t i v i t y a n a l y s i s w h i c h i s i n p r o c e s s

,

a n d a f t e r f u r t h e r a n a l y s i s t o a c c o u n t f o r

m e t e o r o l o g i c a l b i n f r e q u e n c i e s a n d s p a t i a l

v a r i a b i l i t y

, w i l l s e r v e a s t h e b a s i s f o r e v a l u a t i n g

v a r i o u s c o n t r o l s t r a t e g i e s f o r S I P d e v e l o p m e n t

. R e s u l t s f r o m t h i s s e n s i t i v i t y a n a l y s i s

, i n t h e f o r m o f

p p b / T P D o r μ g / m 3 / T P D w i l l b e l i n k e d w i t h

e c o n o m i c a l c o n s i d e r a t i o n s ( $ / t o n ) a n d w i t h a

h e a l t h / e x p o s u r e a n a l y s i s t o d e v e l o p t h e m o s t c o s t

e f f e c t i v e a n d h e a l t h

- b e n e f i c i a l s t r a t e g y f o r

a t t a i n i n g b o t h t h e 8

- h o u r o z o n e a n d a n n u a l P M 2

. 5

s t a n d a r d s

.

O z o n e P M 2

. 5

S c r u b b e r

a n d / o r

S C R a t m a x i m u m

r e d u c t i o n

( p p b ) r e d u c t i o n

p e r t o n

( p p b / T P D ) e p i s o d e

a v e r a g e

r e d u c t i o n

( μ g / m 3 ) r e d u c t i o n

p e r t o n

( μ g / m 3 / T P D )

B r a n c h 5 0

. 3 3 0

. 3 6 0

. 0 0 2 3

B o w e n

- - 0

. 4 2 0

. 0 0 2 4

H a m m o n d 5 0

. 4 5 0

. 3 0 0

. 0 0 3 4

M c D o n o u g h 1

. 5 0

. 2 1 0

. 1 8 0

. 0 0 3 3

S c h e r e r 6 0

. 2 0 0

. 6 6 0

. 0 0 2 0

W a n s l e y

- - 0

. 3 1 0

. 0 0 3 4

Y a t e s 5 0

. 4 5 0

. 2 6 0

. 0 0 2 8

T a b l e 2

. P e r t o n s e n s i t i v i t y ( c o n c e n t r a t i o n / T P D ) o f

o z o n e a n d P M 2

. 5 t o r e d u c t i o n s o f S O 2 a n d N O

x f r o m

m a j o r p o w e r p l a n t s i n G e o r g i a

.