# Analysis of 1

- Hour SO 2 

# NAAQS
Exceedances in Savannah and Rome

Submitted to: Jimmy Johnston Program Manager 2 Planning & Support Program

Submitted by: Data & Modeling Unit Planning & Support Program

Date Submitted:
December 23 , 2013Page 2 of 32



### EXECUTIVE SUMMARY On June 2, 2010, U.S. EPA strengthened that National Ambient Air Quality Standard (NAAQS) for sulfur dioxide (SO 2 ) by adopting a new 1

- hour standard of 75 parts per billion (ppb) 1

, effective August 23, 2010 . EPD has identified three ambient monitors that were recording 1

- hour values in excess of the standard. These monitors are: Savannah

– Lathrop & Augusta,
Savannah

– East President Street, and Rome

– Coosa Eleme ntary. In order to identify the probable cause of these high readings, EPD conducted a set of analyses. These analyses
included the following steps:

1) identification of nearby SO2 sources and Q/d (emissions/distance) analysis; 2) back trajectory analysis on SO2 exceedance days, and 3) AERMOD modeling to quantify source contributions to SO2 exceedances.

The AERMOD modeling was conducted using emissions and stack data requested by EPD and
received from the SO 2 sources in March and May , 2013, respectively

. Following this request,
additional exceed a nces were measured by the Savannah

- Lathrop & Augusta monitor and by the Rome monitor. Additional back trajectory analyses were conducted on the exceedances that were measured prior to November, 2013.

Based on these analyses , it appears that SO2 emissions from Southern States Phosphate &
Fertilizer caused or contributed to the SO2 NAAQS exceedances at the Savannah

- E. President monitor; SO2 emissions from International Paper

– Savannah Mill caused or contribut ed to the SO2 NAAQS exceedances at the Savannah

- Lathrop & Augusta monitor; and SO2 emissions from International Paper

– Rome Linerboard (formerly Temple Inland

– Rome ) and to a lesser degree Plant Hammond caused or contributed to the SO2 NAAQS exceedences at the Rome

- Coosa Elementary School monitor.

Unofficial data indicates that the 3

- year design value for Savannah

– Lathrop & Augusta has violated the NAAQS.



### INTRODUCTION

Two SO 2 monitors in Savannah ( E. President and Lathrop & Augusta ) and one SO 2 monitor in

Rome (Coosa Elementary School ) measured multiple exceedances of the 1

- hour SO 2 NAAQS ( 75 ppb ) from 2011 to 2013. Based on unofficial data through November, 2013, the 3

- year design value for the Savannah Lathrop & Augusta monitor is now 80 ppb, which is a violation of the NAAQS. Although there were multiple exceedances of the 1

- hour SO 2 NAAQS at the
Savannah

- E. President and Rome

– Coosa Elementary monitors , the three year design value
remained below the NAAQS at these two sites

. The purpose of this analysis is to help identify

1 99th percentile of 1

- hour daily maximum concentrations, averaged over 3 yearsPage 3 of 32

which sources contributed to the 1

- hour SO 2 exceedances. This document will focus primarily
on SO 2 exceedances in 2011, 2012, and early 2013 , but also includes some data for exceed a nces in later 2013

. A meteorology analysis of the September e xceedances at Lathrop & Augusta is included in Appendix A. Appendix B discusses three days in Savannah w h ere the winds were
north

- northeast (NNE), but SO 2 remained low.

Table 1 identifies the 1

- hour SO 2 exceedances that were included as part of these analys e s. The technical analysis includes :

1) i dentification of nearby SO 2 sources and Q/d (emissions/distance) analysis ; 2) b ack trajectory analysis on SO 2 exceedance days ; and 3) AERMOD modeling to quantify source contributions to SO 2 exceedances

.

Table 1. Exceedances of the 1

- hour SO2 NAAQS included in analys e s

.

Site Date T ime of Peak SO2 SO2 Peak ( ppb )

E. President ( 13

- 051

- 0021 ) 2/13/2011 9:00 93.0

10/20/2012 9:00 87.3
11/23/2012 9:00 96.6
11/24/2012 2:00 77.9
12/19/2012 10:00 79.3
1/21/2013 10:00 96.0

Lathrop & Augusta ( 13

- 051

- 1002 ) 5/5/2011 6:00 75.8

11/24/2011 8:00 94.8
12/2/2011 10:00 94.2
10/26/2012 8:00 111.7
11/17/2012 9:00 127.6
12/14/2012 7:00 87.1
9/27/13 8:00 117.5
9/28/13 8:00 92.7
9/29/13 8:00 142.1
10/8/13 9:00 101.1
11/5/13 10:00 76.3
11/13/13 7:00 79.9
11/24/13 7:00 76.6
11/30/13 12:00 77.3

Coosa Elementary School ( 13

- 115

- 0003 ) 2/25/2011 0:00 96.0

4/3/2011 18:00 153.1
4/4/2011 15:00 115.6
4/25/2011 16:00 76.3
11/13/2011 13:00 161.8Page 4 of 32 Site Date T ime of Peak SO2 SO2 Peak ( ppb )

Coosa Elementary School ( 13

- 115

- 0003 ) 11/14/2011 12:00 81.4

2/13/2012 12:00 75.9
2/23/2012 14:00 133.5
2/29/2012 21:00 160.6
3/2/2012 11:00 95.6

12/6/2013 11:00 88.0

IDENTIFICATION OF NE ARBY 

### SO 2 SOURCES The 2011 NEI was used to identify all point sources within 50 kilometer ( km ) of each monitor (Table 2, Table 3 and Table 4)

. The SO 2 emissions were identified in tons per year (Q) and the distance from each point source to the associated SO 2 mon itor was calculated in km (d). Next, Q/d, cumulative Q/d, and percent of the cumulative Q/ d were calculated for each source. Sources that had a Q/d > 20 were identified for further analysis (identified with bold) . Sources that had a Q/d < 20 were no longer included in the analysis. The sources that were identified for further analysis accounted for more than 99% of the cumulative Q/d.

Table 2

. Point sources within 50 km of Savannah

- E. President SO 2 monitor.

AIRS NO. Facility Name SO2 ( TPY) Distance

[km] Q/d Cumulative Q/d Percent

Cum Q/d

05100077 Southern States Phosphate &

Fertilizer 1211.44 1.48 819.27 819.27 43.9%
05100007 International Paper

- Savannah 4232.78 7.83 540.52 1359.79 72.9%

05100006 Ga Power Company

- Plant

Kraft 2806.00 12.70 221.01 1580.80 84.8%

10300007 Georgia

- Pacific Consumer

Products LP (Savannah River Mill) 3724.79 32.41 114.92 1695.72 91.0%
05100008 Savannah Acid Plant LLC 120.00 2.49 48.17 1743.89 93.5%
05100010 Weyerhaeuser Company 605.44 14.53 41.67 1785.57 95.8%
05100110 Imperial

- Savannah, L.P. 502.26 12.40 40.51 1826.08 98.0%
10300003 Ga Power Co Plt McIntosh 691.81 33.70 20.53 1846.60 99.1%
05100076 Colonial Terminals, Inc. 82.15 6.58 12.48 1859.09 99.7%
05100148 Arizona Chemical Corporation 31.32 7.66 4.09 1863.17 99.9%

10300014 Ga Power Company

- McIntosh

Combined Cycle Facility 18.07 33.69 0.54 1863.71 100.0%
17900001 Interstate Paper LLC 11.52 49.74 0.23 1863.94 100.0%
10300012 Effingham County Power, LLC 4.70 33.20 0.14 1864.08 100.0%

05100003 Southern LNG Company, L.L.C.

-

Elba Island LNG Terminal

- (Kinder Morgan , Inc.) 0.45 4.36 0.10 1864.19 100.0%
10300004 Simpson Lumber Company, LLC 1.65 33.28 0.05 1864.24 100.0%
05100012 NuStar Asphalt Refining, LLC 0.16 8.71 0.02 1864.25 100.0%
05100046 Gulfstream Aerospace Corp 0.08 15.74 0.00 1864.26 100.0%

05100017 Ga Power Company

- Plant

Boulevard 0.02 7.76 0.00 1864.26 100.0%Page 5 of 32

Table 3

. Point sources within 50 km of Savannah

- Lathrop & Augusta SO 2 monitor.

AIRS NO. Facility Name SO2 (TPY) Distance

[km] Q/d Cumulative Q/d Percent

Cum Q/d
05100007 International Paper

- Savannah 4232.78 1.83 2312.05 2312.05 69.5%

05100006 Ga Power Company

- Plant

Kraft 2806.00 6.61 424.80 2736.85 82.3%

05100077 Southern States Phosphate &

Fertilizer 1211.44 6.59 183.91 2920.76 87.8%

10300007 Georgia

- Pacific Consumer

Products LP (Savannah River Mill) 3724.79 27.51 135.40 3056.16 91.9%
05100110 Imperial

- Savannah, L.P. 502.26 6.12 82.13 3138.29 94.4%
05100010 Weyerhaeuser Company 605.44 8.02 75.46 3213.74 96.6%
05100076 Colonial Terminals, Inc. 82.15 1.77 46.38 3260.12 98.0%
05100148 Arizona Chemical Corporation 31.32 1.11 28.16 3288.27 98.9%
10300003 Ga Power Co Plt McIntosh 691.81 29.63 23.35 3311.62 99.6%
05100008 Savannah Acid Plant LLC 120.00 9.78 12.27 3323.89 100.0%

10300014 Ga Power Company

- McIntosh

Combined Cycle Facility 18.07 29.62 0.61 3324.50 100.0%
17900001 Interstate Paper LLC 11.52 46.78 0.25 3324.75 100.0%
10300012 Effingham County Power, LLC 4.70 26.70 0.18 3324.93 100.0%
05100012 NuStar Asphalt Refining, LLC 0.16 2.14 0.07 3325.00 100.0%
10300004 Simpson Lumber Company, LLC 1.65 25.24 0.07 3325.06 100.0%
17900011 SNF

- Riceboro 3.12 47.96 0.07 3325.13 100.0%

05100003 Southern LNG Company, L.L.C.

-

Elba Island LNG Terminal

- (Kinder Morgan , Inc.) 0.45 11.90 0.04 3325.17 100.0%
05100046 Gulfstream Aerospace Corp 0.08 8.15 0.01 3325.18 100.0%

05100017 Ga Power Company

- Plant

Boulevard 0.02 6.16 0.00 3325.18 100.0%

Table 4

. Point sources within 50 km of Rome

- Coosa Elementary School SO 2 monitor.

AIRS NO. Facility Name SO2 (TPY) Distance

[km] Q/d Cumulative Q/d Percent

Cum Q/d

11500021 International Paper

– Rome

Linerboard (was Temple Inland

– Rome ) 2,202.81 0.77 2,854.92 2,854.92 70.5%

11500003 Ga Power Company

- Plant

Hammond 2,174.44 2.20 988.38 3,843.29 94.9%

01500011 Ga Power Company

- Plant

Bowen 5,888.85 40.15 146.69 3,989.98 98.5%

11500105 General Shale Brick, Inc.

- Plant

40 102.78 1.80 57.04 4,047.02 99.9%
01500032 Gerdau Ameristeel US Inc. 92.12 48.74 1.89 4,048.91 100.0%
05500001 Mount Vernon Mills 32.90 31.66 1.04 4,049.95 100.0%
01500061 Anheuser

- Busch Inc 5.72 49.86 0.11 4,050.07 100.0%

11500077 Ball Container LLC Rome Can

Plant 0.08 21.81 0.00 4,050.07 100.0%

11500095 Packaging Products Corporation,

LLC 0.02 14.96 0.00 4,050.07 100.0%Page 6 of 32

The 2008 SO 2 emissions at the Port of Savannah were obtained from the environmental impact statement report for the Savannah Harbor Expansion Project ( U

. S . Army Corps of Engineers, Environmental Impact Statement Appendix K: Air Emission Inventory and Assessment Savannah Harbor Expansion Project , 2012 ) and are shown in Table 5

. These emissions were estimated by evaluating the air emissions from all cargo

- ca rrying vessels and landside cargo handling equipment at both the G eorgia P ort A uthority (GPA) and privately

- operated terminals at the port. In total , 1,177.5 tons of SO 2 were emitted at the Port of Savannah, with 557.6 tons
from the Garden C ity T erminal, 300.7 tons from the Elba Island LNG Terminal, and 278.7 tons
from the Ocean Terminal and non

- GPA Terminals. Since the SO 2 emissions from these sources were smaller than the SO2 emissions from point sources that were closer to the monitors, no
additional a nalysis was performed for these sources.

Table 5. SO2 emissions in the Port of Savannah by sources (tons/year)

Source SO2 Emissions (TPY)
Garden C ity T erminal 557.6 Ocean Terminal and non

- GPA Terminals 278.7 Elba Island LNG Terminal 300.7 Shifts 27.3 Maintenance D redging 12.4 Tourist B oats 0.9
Total 1,177.5

Due to the close proximity of the SO 2 monitors in Savannah, multiple sources are included in both Table 3 ( E. President ) and Table 4 ( Lathrop & Augusta ). The Q/d analysis for Savannah
indicates that Souther n States Phosphate & Fertilizer (43.9%) and International Paper (29.0%) have the largest contribution to the E. President SO 2 monitor (72.9% of the cumulative Q/d) and International Paper has the largest contribution to the Lathrop & Augusta SO 2 monitor (69.5% of the cumulative Q/d). The Q/d analysis for Rome indicates that International Paper

– Rome
Linerboard has the largest contribution to the Coosa Elementary School SO 2 monitor (70.5% of the cumulative Q/d).



### B ACK TRAJECTORY ANALY SIS Table 6 shows the dat e and time for each 1

- hour SO 2 exceedance prior to mid

- December , 2013, along with the relevant meteorological information. To aid in identifying sources contributing to
each exceedance, 1

- hour average wind analysis and 1

- minute high resolution back trajectory analysis were conducted.Page 7 of 32 Table 6

. Days that exceeded the 1

- hour SO 2 NAAQS and relevant meteorological data

.

Site Date Time of SO2 P eak W ind Speed

(m/s) W ind D irection

(Deg)

Savannah

- E. President ( 13

- 051

- 0021 ) 2/13/2011 9 :00 0.5 253

10/20/2012 9 :00 2.7 271
11/23/2012 9:00 2.7 258
11/24/2012 2:00 2.7 268
12/19/2012 10:00 2.6 21
1/21/2013 10:00 2.7 354

Savannah

- Lathrop & Augusta ( 13

- 051

- 1002 ) 5/5/2011 6:00 1.9 11

11/24/2011 8:00 2.9 27
12/2/2011 10:00 1.8 33
10/26/2012 8:00 2.5 30
11/17/2012 9:00 3.6 40
12/14/2012 7:00 2.5 23
9/27/13 8:00 3.0 35
9/28/13 8:00 2.9 36
9/29/13 8:00 2.1 31
10/8/13 9:00 3.5 35
11/5/13 10:00 2.2 26
11/13/13 7:00 3.1 36
11/24/13 7:00 3.2 35
11/30/13 12:00 1.9 28

Rome

- Coosa Elementary School * ( 13

- 115

- 0003 ) 2/25/2011 0:00 5.1 210

4/3/2011 18:00 5.7 180
4/4/2011 15:00 8.0 190
4/25/2011 16:00 no data no data
11/13/2011 13:00 no data no data
11/14/2011 12:00 no data no data
2/13/2012 12:00 Calm Calm
2/23/2012 14:00 5.1 200
2/29/2012 21:00 2.1 200
3/2/2012 11:00 3.6 230

12/6/2013 11:00 no data no data
* Wind data from R.B. Russell Airp ort Automated Surface Observing Station

For the 1

- hour wind analysis, the average wind speed and wind direction data in Table 6 was used to determine the origin of the air mass leading to the exceedance . Figure 1 shows the

1

- hour wind analysis plot for the Savannah

- E. President monitor. Then , the plot was imported to ArcGIS to overlay the 1

- hour wind analysis plot on a map (see Figure 2 ) to help examine the relationship between major SO 2 sources and each SO 2 exceedance

.Page 8 of 32

Figure 1 . 1

- h ou r wind analysis plot for Savannah

- E. President monitor. The unit s of the x

- axis and y

- axis are kilometers ( km )

.

Figure 2. Example of 1

- hour wind analysis plot overlaid on GIS map. The radius of the circle in the figure is 10 km.

Figure 2 shows the result of 1

- h ou r wind analysis for Savannah

- E. President monitor. High

SO 2 incidences on 02/ 13 11

, 10/ 20 / 12, 11/ 23 / 12, and 11/24/ 12 and are associated with sources at
the west side of the monitor while other exceedances on 12/ 19 / 12 and 01/ 21 / 13 are associated
with sources at the north/northeast side of the monitor. Four possible major contributors were Southern States Phosphate & Fertilizer, BASF Corporation

– Savannah Operations, Georgia

-Page 9 of 32

Pacific Gypsum LCC

– Savannah Plant, and Savannah Acid Plant, LLC. Because SO 2 emissions from BASF Corporation

– S avannah Operations and Georgia

- Pacific Gypsum LCC

– Savannah Plant were zero on those days , these two sources were ruled out.

Next, 1

- minute high resolution back trajectory analyses were performed with 1

- min ute wind data (WS and WD) and 1

- minute SO 2 con centration data provided by the Ambient Monitoring Program staff. The back

- trajectory analysis begins when the first measured 1

- min ute SO 2 concentration exceeds 75 ppb at each monitor location. Then, 1

- minute wind speed and wind
direction measurements at the SO2 monitor site were used to calculate back trajectories. Back trajectories were developed for every minute the SO 2 monitor exceeded 75 ppb. The extent of
back

- trajectory calculation was set to a 3 km radius from the monitoring site. All of the ba ck trajectories were superimposed on a GIS map to help identify sources that may have been contributing to the exceedances

.

Figure 3 through Figure 8 show the results of 1

- minute high resolution back

- trajectory analyses
done for each SO 2 exceedance day

. In most cases, the trajectories show directional consistency.
Based on an analysis of the 1

- hour wind analysis plot and the 1

- minute high resolution back

trajectory plots

, it appears that SO2 emissions from Southern States Phosphate & Fertilizer
caused or contributed to many of the SO 2 NAAQS exceedances at the Savannah

- E. President
monitor

.

Figure 3. High resolution back trajectory for Savannah

- E. President monitor on 02/ 13 / 11

.Page 10 of 32

Figure 4. High resolution back trajectory for Savannah

- E. President monitor on 10/ 20 / 12

.

Figure 5. High resolution back trajectory for Savannah

- E. President monitor on 11/23/ 12

.Page 11 of 32

Figure 6. High resolution back trajectory for Savannah

- E. President monitor on 11/24/ 12

.

Figure 7. High resolution back trajectory for Savannah

- E. President monitor on 12/ 19 / 12

.Page 12 of 32

Figure 8. High resolution back trajectory for Savannah

- E. President monitor on 01/ 21 / 13

.

Figure 9 shows the result of 1

- h ou r wind analysis for Savannah

- Lathrop & Augusta monitor.
All of the SO2 exceedances were associated with sources on the northeast side of the monitor. Two possible contributors were Arizona Chemical Corporation and International Paper

- Savannah. Next

, 1

- minute high resolution back trajector y analyses were conducted for the days
with SO2 exceedances ( Figure 10 through Figure 15 ). According to the 2011 NEI

, annual SO2 emission from International Paper were 4232.78 TPY compared to 31.32 TPY from Arizona Chemical Corporation. Based on the wind trajectory analysis and NEI 2011 emissions

, it appears that the SO2 emissions from International Paper

– Savannah Mill may be responsible for many of the SO2 NAAQS exceedances at the Savannah

- Lathrop & Augusta monitor.Page 13 of 32

Figure 9. 1

- h ou r wind analysis for Savannah

- Lathrop & Augusta monitor. The radius of the circle in the figure is 15 km.

Figure 10. High resolution back trajectory for Savannah

- L athrop & Augusta monitor on
05/05/ 11

.Page 14 of 32

Figure 11. High resolution back trajectory for Savannah

- Lathrop & Augusta monitor on
11/ 24 / 11

.

Figure 12. High resolution back trajectory for Savannah

- Lathrop & Augusta monitor on
12/02/ 11

.Page 15 of 32

Figure 13. High resolution back trajectory for Savannah

- Lathrop & Augusta monitor on
10/ 26 / 12

.

Figur e 14. High resolution back trajectory for Savannah

- L athrop & Augusta monitor on
11/ 17 / 12

.Page 16 of 32

Figure 15. High resolution back trajectory for Savannah

- Lathrop & Augusta monitor on
12/ 14 / 12

.

Figure 16

. High resolution back trajectory for Lathrop & Augusta monitor on 09/27/13.Page 17 of 32

Figure 17. High resolution back trajectory for Savannah

- Lathrop & Augusta monitor on
09/28/13.

Figure 18. High resolution back trajectory for Savannah

- Lathrop & Augusta monitor on
09/29/13.Page 18 of 32

Figure 19. High resolution back trajectory for Savannah

- Lathrop & Augusta monitor on
10/08/13.

Figure 20 shows the result of 1

- h ou r wind analysis for the Rome

- Coosa Elementary School
monitor. All of the SO2 exceedances were associated with sources at the south/south we st side of
the monitor. T he t wo possible contributors were Plant Hammond and International Paper

– Rome Linerboard . Compared to the Savannah monitors, the wind speed is much faster resulting
in less horiz ontal dispersion. Based on the wind directions and the magnitude of wind speed, it appears that the SO2 emissions from International Paper

– Rome Linerboard caused or
contributed to many of the SO2 NAAQS exceedances at the Coosa Elementary School monitor. There is one day that the SO2 emissions from Plant Hammond may have caused or contributed

to a SO2 NAAQS exceedance

. 1

- minute high resolution back trajectory analyses cannot be conducted for the Coosa Elementary Monitor since EPD does not operate a meteorology station
at this site.Page 19 of 32

Figure 20

. 1

- h ou r wind analysis for Rome Coosa Elementary monitor. The radius of the circle in the figure is 30 km.

AERMOD MODELING ANALYSIS AERMOD runs were performed to help quantify the contributions from each source to the

1

- hour SO2 exceedances prior to September, 2013

. In order to use the most accurate SO2 emissions available, letters were sent to each facility included in the analysis requesting hourly emission data for specific exceedance days. The letters requested that :

 Southern States Phosphate & Fertilizer, International Paper

- Savannah Mill

, Georgia Power Compan y ( Plant Kraft ) , Georgia

- Pacific Consumer Products LP (Savannah River Mill), Weyerhaeuser Company, Imperial

- Savannah, L.P., and Georgia Power Co mpany (Plant McIntosh ) submit hourly SO2 emissions for 02/ 13/11, 05/05/11, 11 /24/11, 12/02/11, 10/20/12, 10/26/12, 11/17/ 12, 11/23/12, 11/24/12, 12/14/12, 12/19/12

, and
01/21/13 ;

 Savannah Acid Plant LLC submit hourly SO2 emissions for 02/13/11, 10/20/12, 11/23/12, 11/24/12, 12/19/12, and 01/21/13;

 Colonial Terminals, Inc. and Arizona Chemical Corporation submit hourly SO2

em issions for 05/05/11, 11 /24/11, 12/02/11, 10/26/12, 11/17/12, and 1 2/14/12 ; and



– International Paper

– Rome Linerboard , Georgia Power Company (Plant Hammond), Georgia Power Company (Plant Bowen), and General Shale Brick, Inc. (Plant 40) submit hourly SO2 e missions for 02/25/11, 02/03/11, 02/04/11, 04/25/11, 11/13/11, 11/14/11,

02 /13/12, 02/23/12, and 02/29/12.Page 20 of 32

In addition, the letter requested SO2 emissions for one day prior to the requested date. All facilities provided data (see Appendix C ) . However, some data were more detailed than others. While some facilities could provide hourly SO2 emissions, others could only provide a single SO2 emission rate for each day. The SO2 emission files, stack temperature, and stack velocity

were converte d into AERMOD format for each facility for the days that data was requested. The SO2 emissions on the other days were set equal to zero.

Meteorological data was created for each monitoring site using AERMETv12345 for the period
2011

- 2012. The Savannah

- E. President and Savannah

- Lathrop & Augusta monitoring
locations both contain on

- site meteorological measurements for wind speed and wind direction. The other required meteorological fields were extracted from the Savannah International Airport
ASOS si te (SAV) and the Charleston, SC station (CHS) for upper air measurements. The Rome

- Coosa Elementary School site used surface meteorological fields from the R.B. Russell Airport ASOS site (RMG) in Rome and upper air observations fro m Peachtree City station (FFC). The meteorological data were processed using t he latest version of AERSURFACE v13016 for both airport and site surface charac teristics and using AERMINUTEv 11325 for the 1

- minute ASOS
wind observations. Receptor elevations and hill heights r equired by AERMOD were determined using the AERM APv11103 terrain preprocessor. Terrain elevations from the USGS 30m DEM were used for AERMAP processing.

Each modeling domain contained a 1

- km by 1

- km array of receptors (1 1 x 1 1 ) with 100 meter spacing wit h the center receptor placed at the monitor location. AERMODv12345 was run for 2011 and 2012 for each modeling domain. Modeled SO2 concentrations at the receptor corresponding to the monitor location were compared against SO2 measurements on the days
tha t contained SO2 exceedances

. In addition, the maximum SO2 concentration from the 1

- km by 1

- km array of receptors surrounding the monitor location were compared against SO2 measurements on the days that contained SO2 exceedances. The maximum SO2 concentration was used to identify plumes that may have missed to receptor corresponding to the monitor location due to slight differences in the observed wind direction. Next , the contribution from
each source was evaluated to help identi fy which sources were contributing to the SO2

exceedances

. Since AERMOD outputs SO2 concentrations in  g/m 3 , the SO2 observations were converted from ppb to  g/m 3 by multiplying by 2.62 (e.g., 75 ppb = 196.5  g/m 3 ).

Generally, U.S. EPA requires 5 years o f meteorological data to be used and does not require SO2 observations and SO2 model results to be paired in time and space since AERMOD models a distribution of steady

- state concentrations. It should be noted that this AERMOD analysis generally pairs the SO2 observations and SO2 model results in time and space on exceedance days , an analysis for which AERMOD was not designed. T herefore

, matching of all measured and modeled concentrations should not be expected

.Page 21 of 32

Savannah

- E. President (13

- 051

- 0021)
Fi gure 21 contains the AERMOD receptor array used to model impacts at the Savannah

- E.
President (13

- 051

- 0021) monitor. Figure 22 contai ns a time series plot comparing AERMOD SO2 results at the monitoring site receptor, AERMOD SO2 results for the maximum receptor in the array, and the SO2 observations. Figure 23 contains a Q

- Q plot (unpaired in time) for the SO2 concentrations at the monitoring site receptor a nd the maximum receptor in the array. Figure 2 1 contains the hourly SO2 source contributions from each facility at the receptor corresponding to the monitor location. Figure 2 5 contains the maximum hourly SO2 source contributions from the array of recept ors for each facility. Figure 2 6 contains a summary of the daily maximum observation, daily maximum source contributions from each facility at the receptor corresponding to the monitor location

, and the daily maximum source contributions
from each facilit y from the array of receptor surrounding the monitor location

.

In general, AERMOD tends to under predict the SO2 peaks when using the monitoring site receptor. However, the model performance is improved for the higher SO2 values when using
the maximum re ceptor in the array surrounding the monitoring site. Based on the model results, it appears that the SO2 emissions from Southern States Phosphate & Fertilizer caused or
contributed to many of the SO2 NAAQS exceedances at the Savannah

- E. President monitor.

Figure 21

. AERMOD receptor array for Savannah

- E. President (13

- 051

- 0021) monitor

.Page 22 of 32

Figure 22

. AERMOD SO2 results at the Savannah

- E. President monitoring site receptor (green), AERMOD SO2 results for the maximum receptor in the array (red), and the SO2 observations (black).

Figure 23

. Q

- Q plot (unpaired in time) for the SO2 concentrations at the Savannah

- E. President monitoring site receptor and the maximum receptor in the array.Page 23 of 32

Figure 2 4

. Hourly SO2 source contributions from each facility at the receptor corresponding to
the Savannah

- E. President monitor location.

Figure 2 5

. Maximum hourly SO2 source contributions from each facility from the array of receptors surrounding the Savannah

- E. President monitor.Page 24 of 32

Figure 2 6

. Bar chart summary of the daily maximum observation, daily maximum source contributions from each facility at the receptor corresponding to the Savannah

- E. President monitor location, and the daily maximum source contributions from each facility from the array of receptor surrounding the Savannah

- E. President monitor location.

Savannah

- Lathrop & Augusta (13

- 051

- 1002) Figure 2 7 contain s the AERMOD receptor array us ed to model impacts at the Savannah

- Lathrop & Augusta (13

- 051

- 1002) monitor. Figure 2 8 contains a time series plot comparing
AERMOD SO2 results at the monitoring site receptor , AERMOD SO2 results for the max imum receptor in the array

, and the SO2 observations . Figu re 2 9 contains a Q

- Q plot (unpaired in time) for the SO2 concentrations at the monitoring site receptor and the maximum receptor in the

array . Figure 30 contains the hourly SO2 source contributions from each facility at the receptor

cor responding to the monitor location . Figure 31 contains the maximum hourly SO2 source contributions from the array of recepto rs for each facility. Figure 32 contains a summary of the daily maximum observation, daily maximum source contributions from each facility at the receptor corresponding to the monitor location, and the daily maximum source contributions from each facility from the array of receptor surrounding the monitor location.

In general, AERMOD tends to under predict the SO2 peaks when using t he monitoring site
receptor as well as when using the maximum receptor in the array surrounding the monitoring
site. Based on the model results, it appears that that the SO2 emissions from International Paper

– Savannah Mill caused or contributed to many of the SO2 NAAQS exceedances observed at the
Savannah

- Lathrop & Augusta monitor. Although Figure 32 indicates impacts from Plant KraftPage 25 of 32

on 12/02/11, it can be seen in Figure 30 and Figure 31 that the Plant Kraft impacts occur prior to
the observed SO2 exceedance on that day.

Figure 2 7

. AERMOD receptor array for Savannah

- Lathrop & Augusta (13

- 051

- 1002) monitor

.Page 26 of 32

Figure 2 8

. AERMOD SO2 results at the Savannah

- Lathrop & Augusta monitor site receptor (green), AERMOD SO2 results for the maximum receptor in the array (red), and the SO2 observations (black).

Figure 2 9

. Q

- Q plot (unpaired in time) for the SO2 concentrations at the Savannah

- Lathrop & Augusta monitoring site receptor and the maximum receptor in the array.Page 27 of 32

Figure 30

. Hourly SO2 source contributions from each facility at the receptor corresponding to
the Savannah

- Lathrop & Augusta monitor location.

Figure 31

. Maximum hourly SO2 source contributions from each facility from the array of receptors surrounding the Sava nnah

- Lathrop & Augusta monitor.Page 28 of 32

Figure 32

. Bar chart summary of the daily maximum observation, daily maximum source contributions from each facility at the receptor corresponding to the Savannah

- Lathrop & Augusta monitor location, and the daily maximum source contributions from each facility from the array of receptor surrounding Savannah

- Lathrop & Augusta monitor location.

Rome

- Coosa Elementary School (13

- 115

- 0003) Figure 33 contains the AERMOD receptor array used to model impacts at the Rome

- Coosa Elementary School (13

- 115

- 0003) monitor. Figure 3 4 contains a time series plot comparing
AERMOD SO2 results at the monitoring site receptor , AERMOD SO2 results for the max imum

r eceptor in the array

, and the SO2 observations . Figu re 5 1 contains a Q

- Q plot (unpaired in time) for the SO2 concentrations at the monitoring site receptor and the maximum receptor in the

array . Figure 3 6 contains the hourly SO2 source contributions from each facility at the receptor corresponding to the monitor location . Figure 3 7 contains the maximum hourly SO2 source contributions from the array of recepto rs for each facility. Figure 3 8 contains a summary of the daily maximum observation, daily maxim um source contributions from each facility at the receptor corresponding to the monitor location, and the daily maximum source contributions from each facility from the array of receptor surrounding the monitor location.

In general, AERMOD tends to slight ly under predict the SO2 peaks when using the monitoring site receptor. However, the model tends to over predict the SO2 peaks when using the maximum receptor in the array surrounding the monitoring site. Based on the model results, it appears that
the S O2 emissions from International Paper

– Rome Linerboard and to a lesser degree Plant
Hammond caused or contributed to many of the SO2 NAAQS exceedances at the Rome

- Coosa Elementary School monitor

.Page 29 of 32

Figure 33

. AERMOD receptor array for Rome

- Coosa Elementary School (13

- 115

- 0003)
monitor

.

Figure 3 4

. AERMOD SO2 results at the Rome

– Coosa Elementary monitoring site receptorPage 30 of 32

(green), AERMOD SO2 results for the maximum receptor in the array (red), and the SO2 observations (black).

Figure 3 5

. Q

- Q plot (unpaired in time) for the SO2 concentrations at the Rome

– Coosa Elementary monitoring site receptor and the maximum receptor in the array.Page 31 of 32

Figure 3 6

. Hourly SO2 source contributions from each facility at the receptor corresponding to
the Ro me

– Coosa Elementary monitor location.

Figure 3 7

. Maximum hourly SO2 source contributions from each facility from the array of receptors surrounding the Rome

– Coosa Elementary monitor.

Figure 3 8

. Bar chart summary of the daily maximum observation, daily maximum source contributions from each facility at the receptor corresponding to the Rome

– Coosa ElementaryPage 32 of 32

monitor location, and the daily maximum source contributions from each facility from the array of receptor surrounding the Rome

– Coosa Elementary monitor location.



### CONCLUSIONS

T echnical analyses were performed to help identify SO2 emission sources that contributed to
SO2 exceedances in Rome and Savannah. The se analyses included:

1) identification of nearby SO2 sources and Q/d (emissions/distance) analysis ; 2) back trajectory analysis on SO2 exceedance days, and 3) AERMOD modeling to quantify source contributions to SO2 exceedances.

Based on these analyses , it appears that the SO2 emissi ons from Southern States Phosphate &
Fertilizer caused or contributed to the SO2 NAAQS exceedances at the Savannah

- E. President monitor; the SO2 emissions from International Paper

– Savannah Mill caused or contributed to the SO2 NAAQS exceedances at the Savannah

- Lathrop & Augusta monitor; and the SO2 emissions from International Paper

– Rome Linerboard and to a lesser degree Plant Hammond
caused or contributed to the SO2 NAAQS exceedances at the Rome

- Coosa Elementary School
monitor.