## BART EXEMPTION MODELING SUMMARY REPORT FOR
PCS Nitrogen
AUGUSTA, GEORGIA

Submitted to: 

## GEORGIA ENVIRONMENTAL PROTECTION DIVISION

Prepared for:

Prepared by:
MACTEC Engineering and Consulting, Inc.

Kennesaw, Georgia
Project No. 6306-06-0034

October 2006BART Exemption Summary Report October, 2006

PCS Nitrogen. – Augusta, GA MACTEC Project No. 6306-06-0034

Source-Specific Modeling Protocol Summary Report ii 1. INTRODUCTION.......................................

................................................... .............................1-1 1.1 BACKGROUND .........................................

................................................... .................1-1 1.2 OBJECTIVES.........................................

................................................... ......................1-2 1.3 LOCATION OF SOURCE VS. RELEVANT CLASS I AREAS ...... .............................1-2 1.4 SOURCE IMPACT EVALUATION CRITERIA .................. .........................................1-3
2. SOURCE DESCRIPTION .................................

................................................... .....................2-1 2.1 UNIT SPECIFIC SOURCE DATA..........................

................................................... ....2-1 2.2 BOUNDARY CONDITIONS ................................

................................................... ......2-1
3. GEOGRAPHICAL AND METEOROLOGICAL DATA............... ........................................3-1 3.1 MODELING DOMAIN AND TERRAIN........................ ...............................................3-1 3.2 LAND USE...........................................

................................................... ........................3-1 3.3 METEOROLOGICAL DATA BASE ........................... ..................................................3 -1 3.3.1 MM5 Simulations ....................................

................................................... ........3-1 3.3.2 Measurements and Observations ...................... ..................................................3 -1 3.4 AIR QUALITY DATA BASE..............................

................................................... ........3-1 3.4.1 Ozone Concentrations – Measured or Modeled......... .........................................3-1 3.4.2 Ammonia Concentrations – Measured or Modeled ....... .....................................3-2 3.4.3 Concentrations of Other Pollutants – Measured or Mo deled..............................3-2 3.4.4 β -Extinction Coefficients for Particulates and Ammon ia...................................3-2 3.5 NATURAL CONDITIONS AT CLASS I AREAS................ .........................................3-3
4. AIR QUALITY MODELING METHODOLOGY................... ...............................................4-1 4.1 PLUME MODEL SELECTION..............................

................................................... .....4-1 4.1.1 Major Relevant Features of CALMET .................. .............................................4-1 4.1.2 Major Relevant Features of CALPUFF ................. .............................................4-1 4.2 MODELING DOMAIN CONFIGURATION FOR 12 KM............ ................................4-1 4.3 CLAMET METEOROLOGICAL MODELING..................... ........................................4-5 4.4 CALPUFF COMPUTATIONAL DOMAIN AND RECEPTORS......... .........................4-5 4.5 CALPUFF MODELING OPTIONS SELECTIONS................ .......................................4-5 4.6 LIGHT EXTINCTION AND HAZE IMPACT CALCULATIONS ...... .........................4-6 4.7 MODELING RESULTS...................................

................................................... ............4-7
5. SUMMARY ............................................

................................................... ..................................5-1
6. REFERENCES.........................................

................................................... ................................6-1BART Exemption Summary Report October, 2006

PCS Nitrogen. – Augusta, GA MACTEC Project No. 6306-06-0034

Source-Specific Modeling Protocol Summary Report ii i LIST OF TABLES

Table 1: PCS Location and Distance to Class I Area s.................................................. ............................1-3

Table 2: PCS Modeled Stack Parameters and emissions rates ............................................. .....................2-2

Table 3: Relative Humidity Factor Data............

................................................... ....................................4-1

Table 4: Modeling Domain Coordinates for 12 Km gri d.................................................. ........................4-1

Table 5: Modeling Domain Coordinates for 4 Km grid

................................................... .........................4-2

Table 6: Modeling Results for 12 Km grid........................... .......................................... 4-5

Table 7: Modeling Results for 4 Km grid.............................. ......................................... 4-6

LIST OF FIGURES

Figure 1 PCS Location and Corresponding Class I are as

Figures 2a & 2b: Modeling Domains

EXIBIT A

Exhibit A: CD diskette of model runsBART Exemption Summary Report October, 2006

PCS Nitrogen. – Augusta, GA MACTEC Project No. 6306-06-0034

Source-Specific Modeling Protocol Summary Report 1- 1 1. INTRODUCTION

MACTEC Engineering and Consulting, Inc. (MACTEC) is submitting the following Best Available Retrofit Technology (BART) Exemption Modeling summa ry report on behalf of the PCS Nitrogen Inc. (PCS) located in Augusta, Georgia. This summary re port demonstrates that the PCS facility can be excluded from any additional assessment under the B ART rule since modeling demonstrates that the facilities emissions have an insignificant impact o n all surrounding Class I areas.

1.1 BACKGROUND

BART represents EPA’s first regulatory step towards eliminating any visible impairments from industria l sources of pollutions by the year 2064. It is aime d at reducing emissions from old “grandfathered” sources of emissions of pollutants that impact visi bility. There are three criteria to determine if a source is part of the BART group of sources:

1. Is a source within the 26 listed industrial cate gories?

2. Was the source constructed within the time frame of August 1962 to August 1977?

3. Does the source emit more than 250 TPY of any vi sual impairment pollutant?

It is that select group that EPA has decided to foc us attention on. Of that select group if modeling shows that the facility does not have a significant impac t on a Class I area (meaning less than 0.5 deciview change in visibility on a Class I area receptor) th en the unit need not go through the BART process. Otherwise a BART assessment must be completed which must look at adding controls to reduce emissions and evaluate their overall impact on the Class I area(s). The conclusion of a BART analysis is an optimum solution of controls versus impact and t he implementation of this solution written into the state regulations by Dec 2007. In PCS’s case, for the most part the entire facility qualifies under a ll three criteria, and all emission sources must be evaluate d.BART Exemption Summary Report October, 2006

PCS Nitrogen. – Augusta, GA MACTEC Project No. 6306-06-0034

Source-Specific Modeling Protocol Summary Report 1- 2 1.2 OBJECTIVES

Once a particular source and emission unit is deter mined to be BART eligible the first step is to dete rmine whether a BART-eligible source can be excluded from BART controls by demonstrating that the source cannot be reasonably expected to cause or contribut e to visibility impairment in a Class I area. The preferred approach is an assessment with an air qua lity model such as CALPUFF or other appropriate model followed by comparison of the estimated 24-hr visibility impacts against a threshold above estimated natural conditions to be determined by th e States. The threshold to determine whether a sing le source “causes” visibility impairment is set at 1.0 deciview change from natural conditions over a 24- hour averaging period in the final BART rule (70 FR 3911 8). The guidance also states that the proposed threshold at which a source may “contribute” to vis ibility impairment should not be higher than 0.5 deciviews (perhaps lower for some particular Class I area). EPA recommends that the 98 th percentile value from the modeling be compared to the contribu tion threshold of 0.5 deciviews to determine if a source does not contribute to visibility impairment , and therefore is not subject to BART. Whether or not the 98 th percentile value exceeds the threshold must be de termined at each Class I area. Over an annual period, this implies the 8th highest 24-hr value at a particular Class I area is compared to the contr ibution threshold. Over a 3-year modeling period, the 98 th percentile value may be interpreted as the highes t of the three annual 98th percentile values at a partic ular Class I area or the 22nd highest value in the combined three year record, whichever is more conse rvative. The objective of this modeling summary report is to demonstrate that the PCS site located in August, Georgia does not contribute to visibilit y impairment in any Class I area and further assessme nt under BART is not required.

1.3 LOCATION OF SOURCE VS. RELEVANT CLASS I AREAS

Table 1 below provides the location of the PCS faci lity and the Class I areas near the site. The dist ance from PCS to the nearby class I areas was determined by calculating the distance from the modeled stack at the site to each of the receptor locations, whic h represent the Class I area boundary. These bound ary receptors (taken from the National Park Service web site) were used to determine the shortest distance between the PCS Nitrogen site to the nearby Class I areas. As shown in Table 1, and Figure 1, PCS sit e is within 300 km of eight Class I areas. All eight Cl ass I areas were evaluated as part of the exemption modeling.BART Exemption Summary Report October, 2006

PCS Nitrogen. – Augusta, GA MACTEC Project No. 6306-06-0034

Source-Specific Modeling Protocol Summary Report 1- 3

Table 1: PCS Location and Distance to Class I Area s

Site/ Class I Area LCC (Easting) – km LCC (Northing)

– km Shortest Distance to

Flomaton (km)
PCS 1390.6 -610.4 -- Cape Romain 1610.2 -627.0 220
Cohutta 1131.5 -484.1 288
Wolf Island 1485.8 -828.1 238 Great Smokey Mountains 1241.2 -400.0 258 Joyce Kilmer - Slickrock 1177.1 -429.2 280 Shining Rock Wilderness 1276.4 -416.0 225
Okeefenokee 1401.4 -877.3 267 Linville Gorge 1349.5 -350.9 263

1.4 SOURCE IMPACT EVALUATION CRITERIA

The maximum 24 hour results from the CALPOST model for each modeled year using a 12 km meteorological grid spacing were compared to the 0. 5 deciview (DV) significant impact level. If the results of this CALPOST analysis show that the impa ct is below this level, then the site qualifies as an exempted source and no additional evaluation is nee ded. If this criteria is not meet, then the model is rerun using a finer meteorological grid spacing (4 km) and the 98 th percentile result for each year is compared to the 0.5 dv value. For this assessment, the 98 th percentile level is the 8 th highest deciview value of all receptors. If this second criteria is meet, then the facility is determined to be an exe mpted source, otherwise a full BART analysis is required.BART Exemption Summary Report October, 2006

PCS Nitrogen. – Augusta, GA MACTEC Project No. 6306-06-0034

Source-Specific Modeling Protocol Summary Report 1- 4 Source: Google Earth

Figure 1 Location of PCS Nitrogen and respective Cl ass I areas PCS Nitrogen

Okefenokee Wolf Island Cape Romain Cohutta a Joycee Kilmer

Linville George

Shining Rock

Great Smoky MountainsBART Exemption Summary Report October, 2006

PCS Nitrogen. – Augusta, GA MACTEC Project No. 6306-06-0034

Source-Specific Modeling Protocol Summary Report 2- 1 2. SOURCE DESCRIPTION

PCS owns and operates a nitrogenous fertilizer manu facturing facility in Augusta, Georgia. The plant produces ammonia, nitric acid, urea, carbon dioxide , ammonium nitrate, and urea-ammonium nitrate solutions. In the ammonia plant, natural gas is re formed and mixed with atmospheric air to form ammonia in a series of reaction steps. The plant o perates two nitric acid plants, which combust the ammonia in the presence of air to form NOx, which i s routed through absorption columns to form nitric acid. Ammonium nitrate is formed at the plant by m ixing gaseous ammonia with nitric acid. The neutralized solution is then concentrated in prill towers to form a solid. The plant also operates a Urea production facility which combines carbon dioxide ( produced from the ammonia plant) with ammonia to
form urea. The urea is then concentrated in a Pril l Tower. The ammonia plant, nitric acid plants, ammonium nitrate operations, and urea plant were bu ilt between the eligibility dates of August 1962 to August 1977; the processes are on the list of 26 li sted processes (chemical plants); and the units hav e the potential NOx emissions greater than 250 tpy. All these units are therefore BART eligible. The boile rs on site were not built during the BART eligibility dates, however, they are in place to support the chemical plant operations (in terms of supplying st eam), therefore they are conservatively included as BART eligible sources to be modeled even though som e interpretations state that just supplying steam i s not considered supporting the operation.

2.1 UNIT SPECIFIC SOURCE DATA

The exemption modeling used the stacks parameters f or the PCS plant as summarized in Table 2. The stack exhaust gas velocities and exhaust temperatur es are based on results from recent stack tests
conducted on the individual stacks. The modeled em ission rates were based on emission factors that we re derived from either stack testing or preferably CEM data multiplied by the maximum production day that occurred for the particular process unit during the study period. Where neither stack data nor CEM da ta was available engineering judgment was used to gene rate an emission limit that corresponded to the expected maximum emission rate.BART Exemption Summary ReportOctober, 2006PCS Nitrogen. – Augusta, GAMACTEC Project No. 6306-06-0034Source-Specific Modeling Protocol Summary Report 2-1Table 2: Modeled Stack Parameters and modeled emissions ratesBaseElevationStackHeight Diameter VelocitySO2NOxPM10NH3No. Unit IDStackID Process Description(m) (m) (m) (m/s)ExhaustTemp.(K)g/sec g/sec g/sec g/sec1 A 103 ST03 C1 AN Dryer 0 31.1 0.98 16.15 302.6 00 0.87 0.762 A104 ST04 C1 AN Cooler 0 29.6 0.76 17.98 302 0 02.18 1.053 A105 ST05 C1 AN Prill Tower 0 36.3 1.9 0.001** 322 0 0 0.6 0.644 AN01 ST01 C1 AN Neutralizer 0 35.7 0.6 19.56 3720 0 1.03 6.825 A201 ST09 C2 AN Prill Tower 0 61 2.63 25.55 300.60 0 0.37 0.436 A201 ST06 C2 AN Prill Tower 0 65* 1.21 24.68 302.6 0 0 0.1 1.567 A202 ST07 C2 AN Cooler 0 29 1.82 15.24 305.6 0 00.49 3.158 A204 ST10 C2 AN LD Dryer 0 29 1.82 12.31 302.6 00 0.16 1.699 AN02 ST02 C2 AN Neutralizer 0 29 0.79 19.55 371.50 0 0.9 14.9310 U201 ST11 Urea Prill Tower-Inner 0 65* 1.4 15.05327.6 0 0 0.2 2.811 U201 ST33 Urea Prill Tower-Outer 0 65* 2.63 24.99 316.5 0 0 0.94 2.8612 N101 ST18 C1 Nitric Acid Plant 0 41.9 0.96 31.69309.1 0 56.86 0 013 N201 ST19 C2 Nitric Acid Plant 0 21 1.52 31.69 448.6 0 12.68 0 15.0314 NST1 ST20 Nitric Acid tanks 0 3.7 0.3 0.001** 294 0 0.02 0 015 AB01 ST21 H-6531 Oil 0 38.6 1.52 3.77 422 0.69 1.82 0.18 016 AB01 ST21 H-6531 NG 0 38.1 1.52 3.77 422 0 3.580.18 017 AB03 ST24 H-6532 0 31.7 1.52 1.28 438.7 0 1 0.18018 AM01 ST12 Primary Reformer NG 0 32.9 4.23 12.8 455.4 0 1.14 0.29 019 AM01 ST12 Primary Reformer PG 0 32.9 4.23 12.8 455.4 0 1.51 0.27 020 FL01 ST36 NH3 Storage Flare 0 30.5 0.07 5.36 4220 0.0037 0 021 AM04 ST15 Solution Regenerator 0 65* 0.46 30.48380.4 0 0 0 0.3822 U202 ST27 Urea Plant Low P Vent 0 65* 0.52 0.61313.7 0 0 0 0.02523 U203 ST28 Urea Plant High P Vent 0 65* 0.15 13.47 331.5 0 0 0 6.524 U204 ST29 Dust Washer 0 65* 3.5 1.43 380.9 0 0 0.14 0.59Note: LCC Easting 1390.554 Km (Assumed for all sources)LCC Northing -610.375 KM (Assumed for all sources)** Horizontal duct so modeled with a very low velocity* Actual stack height exceeds 65 metersBART Exemption Summary ReportOctober, 2006PCS Nitrogen. – Augusta, GAMACTEC Project No. 6306-06-0034Source-Specific Modeling Protocol Summary Report 2-2Table 2 (continued)BaseElevationStackHeight Diameter VelocitySO2NOxPM10NH3No. Unit IDStackID Process Description(m) (m) (m) (m/s)ExhaustTemp.(K)g/sec g/sec g/sec g/sec25 U205 ST30 Urea Process Tanks 0 65* 0.5 0.61 313.7 0 0 0 0.0826 U206 Urea Warehouse 0 0 2 4.8 273 0 0 0 0.2227 AM02 ST13Startup Vent for AmmoniaPlant 0 65* 1.06 61.26 338.7 0 0 0 0.7528 U207 ST31 Urea Compressor 0 27.4 0.3 55.3 314.70 0 0 0.0329 ACI2 ST17 ACI Skids 0 13.7 0.4 24.39 299.7 0 0 00.6130 CT1 6-Cell Cooling Tower 0 5 2 6.1 300 0 0 0.27 031 AM05 NH3 Plant Fugitives 0 9.14 2 0.001** 2730 0 0 2.2632 CT5 2-Cell Cooling Tower 0 5 2 6.1 300 0 0 0.01 033 A203 ST08 C2 AN Cooler By-pass 0 29 1.22 16.31 310.8 0 0 0.87 0.0734 A 205 ST35 AN Pond Evaporator 0 28.96 1.22 4.87300 0 0 0 0.6735 CT2 4-Cell Cooling Tower 0 5 2 6.1 300 0 0 0.05 036 CT3 2-Cell Cooling Tower 0 5 2 6.1 300 0 0 0.01 037 CT4 1-Cell Cooling Tower 0 5 2 6.1 300 0 0 0.04 038 GT01 ST12 Gas Turbine 0 32.92 4.237 12.8 455 0 10.15 0.25 0Note: LCC Easting 1390.554 Km (Assumed for all sources)LCC Northing -610.375 KM (Assumed for all sources)BART Exemption Summary Report October, 2006

PCS Nitrogen. – Augusta, GA MACTEC Project No. 6306-06-0034

Source-Specific Modeling Protocol Summary Report 2- 1 As per the common VISTAS modeling protocol (page 42 ), the modeling evaluation did not included building downwash, because all Class 1 areas being evaluated are greater than 50 km away from the site

.

The following stacks have actual stack heights that exceed 65 meters and were installed after 1970:

• ST09
• ST11
• ST33
• ST15
• ST27
• ST28
• ST29
• ST30
• ST13

Therefore in the modeling these stacks were given t he height 65 meters rather than the true height (as shown in the table) which exceeded the allowable GE P height according to 40 CFR 51.100.

2.2 BOUNDARY CONDITIONS

Model options and switches were used as set in the example models as provided on the Earth Tech website ( www.src.com ).BART Exemption Summary Report October, 2006

PCS Nitrogen. – Augusta, GA MACTEC Project No. 6306-06-0034

Source-Specific Modeling Protocol Summary Report 3- 1

3. GEOGRAPHICAL AND METEOROLOGICAL DATA

3.1 MODELING DOMAIN AND TERRAIN

The modeling data to be utilized for the modeling e valuation is the CALMET data provided by VISTAS via Georgia EPD. The modeling domain consists of t he area which includes the site, all eight class 1 areas being evaluated, with an additional 50 km buf fer around this area. The area around the site is primarily flat terrain.

3.2 LAND USE

The area around the site is rural and is primarily agricultural land use.

3.3 METEOROLOGICAL DATA BASE

All the met data used was provided by the VISTAS.

3.3.1 MM5 Simulations

As provided by VISTAS.

3.3.2 Measurements and Observations

None.

3.4 AIR QUALITY DATA BASE

3.4.1 Ozone Concentrations – Measured or Modeled

The ozone concentrations were modeled using the thr ee years of ozone data as provided by Earth Tech on their website ( http://www.src.com/verio/download/download.htm ). The OZONE.DAT file used in each year of the model runs was extracted from the corre sponding year data taken from the Earth Tech websit e. The CALPRO GUI was used to extract the data by prov iding the domain being used for the CALPUFF
model.BART Exemption Summary Report October, 2006

PCS Nitrogen. – Augusta, GA MACTEC Project No. 6306-06-0034

Source-Specific Modeling Protocol Summary Report 3- 2 3.4.2 Ammonia Concentrations – Measured or Modeled

As noted in the VISTAS common protocol (page 42) a constant ammonia background concentration of 0.5 ppb was used for the CALPUFF modeling. For mode ling ammonia emissions from the plant, physical properties of ammonia inserted in the model were ta ken from University of South Florida professor Dr. Noreen Poor, who provided the following data which we have confirmed as being representative:

Diffusivity - (cm^2/s) = 0.234, Alpha Star=176, Reactivity =30, Mesophyll Resistance. =0 s/cm, Henry’s Law =7.20 x 10-4, Wet (liquid) scavenging coefficient (1/s) = 7 x 10- 4
These are dry and wet deposition parameters of whic h only the wet deposition values were used.

3.4.3 Concentrations of Other Pollutants – Measured or Modeled

Per the “Federal Land Managers’ Air Quality Related Values Workgroup (FLAG) Phase I report (December 2000)” the background SO 4 concentration (BKSO4) was calculated based on the reported hygroscopic value for each of the Class I areas div ided by 3. The hygroscopic value for all of the Cl ass I areas being studied is 0.9 (taken from the FLAG doc ument), therefore a 0.3 value was used for the BKSO4 variable for all months. The soil background (BKSOIL) concentration was set to the non-hygroscopic value as set by the FLAG document. This value is 8.5 for all eight of the Class 1 are as.

3.4.4 β -Extinction Coefficients for Particulates and Ammon ia

The modeling was completed using two worst case ass umptions. First, it was assumed that all the particulate emitted from the facility is fine parti culate which has a β extinction coefficient of 1.0 (versus 0.6 for larger particulate). Second, it was assumed that all the ammonia emitted from the facility tha t is transported to the Class I area is converted into e ither ammonium sulfate or nitrate. To accomplish th is in the ammonia species was given in CALPOST run was gi ven a β extension coefficient equivalent to those compounds of 3.0 which is the second worst case ass umption.BART Exemption Summary Report October, 2006

PCS Nitrogen. – Augusta, GA MACTEC Project No. 6306-06-0034

Source-Specific Modeling Protocol Summary Report 3- 3 Month Cape Romain Cohutta Wolf Island Great Smokey Mountains Joyce Kilmer Shining Rock Wilderness Okefenokee Linville Gorge January 2.9 3 3.1 3 3 2.9 3.2 2.9 February 2.9 3 3.1 3 3 2.9 3.2 2.9

March 3.3 3.1 3.3 3.1 3.1 3.1 3.4 3.1 April 3.3 3.1 3.3 3.1 3.1 3.1 3.4 3.1 May 3.3 3.1 3.3 3.1 3.1 3.1 3.4 3.1

June 3.9 3.6 3.9 3.6 3.6 3.7 3.9 3.7 July 3.9 3.6 3.9 3.6 3.6 3.7 3.9 3.7 August 3.9 3.6 3.9 3.6 3.6 3.7 3.9 3.7 September 3.3 3.3 3.6 3.2 3.2 3.2 3.6 3.1

October 3.3 3.3 3.6 3.2 3.2 3.2 3.6 3.1

November 3.3 3.3 3.6 3.2 3.2 3.2 3.6 3.1

December 2.9 3 3.1 3 3 2.9 3.2 2.9 3.5 NATURAL CONDITIONS AT CLASS I AREAS

The relative humidity used for each Class I area be ing modeled was based on data taken from the FLAG document. Table 3 below provides the monthly re lative humidity that was used for each of the eight
Class I areas.

Table 3: Relative Humidity Factor DataBART Exemption Summary Report October, 2006

PCS Nitrogen. – Augusta, GA MACTEC Project No. 6306-06-0034

Source-Specific Modeling Protocol Summary Report 4- 1

4. AIR QUALITY MODELING METHODOLOGY

4.1 PLUME MODEL SELECTION

The modeling was completed using the VISTAS recomme nded CALPUFF version 5.754 for BART modeling as posted on the Earth Tech website. The modeling was completed using the 12-km and 4-Km meteorological data files provided by VISTAS (via G eorgia EPD). The sample CALPUFF model and CALPOSTL input files posted on the Earth Tech websi te was used for the modeling assessment.

4.1.1 Major Relevant Features of CALMET

CALMET was not run for this application as all met data has been provided by VISTAS. VISTAS supplied met data was generated using CALMET versio n 5.7.

4.1.2 Major Relevant Features of CALPUFF

The modeling utilized the MESOPUFF II module for ch emical mechanism portion of the model. The integrated puff sampling methodology options were c hosen. For running the CALPOST processor, the visibility Method 6 option was used using the month ly relative humidity values identified above. The species considered in the visibility analysis inclu ded SO4, NO3, EC, SOA, soil, and coarse PM.

4.2 MODELING DOMAIN CONFIGURATION FOR 12 KM

The domain consists of the area which included the site, all eight class 1 areas, with an additional 5 0 km buffer around this area. Table 5 provides the coor dinates of the area bounded by the modeling domain.

Table 4: Modeling Domain Coordinates for 12 Km gri d

Location LCC (Easting) – km LCC (Northing) – km
Southwest Corner 1037.973 -1001.974
Southeast Corner 1709.973 -1001.974
Northeast Corner 1709.973 -269.974
Northwest Corner 1037.973 -269.974BART Exemption Summary Report October, 2006

PCS Nitrogen. – Augusta, GA MACTEC Project No. 6306-06-0034

Source-Specific Modeling Protocol Summary Report 4- 2

Table 5 Modeling Domain Coordinates for 4 Km grid

Location LCC (Easting) – km LCC (Northing) – km
Southwest Corner 718.005 -1214.003
Southeast Corner 1706.005 -1214.003
Northeast Corner 1706.005 -562.003
Northwest Corner 718.005 -562.003

Figure 2a depicts the modeling domain on a map for the 12 km met grid spacing and Figure 2b depicts th e modeling domain on a map for the 4 km met grid spac ing.BART Exemption Summary Report October, 2006

PCS Nitrogen. – Augusta, GA MACTEC Project No. 6306-06-0034

Source-Specific Modeling Protocol Summary Report 4- 3 Figure 2a. Modeling Domain for 12 km Grid SpacingBART Exemption Summary Report October, 2006

PCS Nitrogen. – Augusta, GA MACTEC Project No. 6306-06-0034

Source-Specific Modeling Protocol Summary Report 4- 4 Figure 2b . Modeling Domain for 4 km Grid SpacingBART Exemption Summary Report October, 2006

PCS Nitrogen. – Augusta, GA MACTEC Project No. 6306-06-0034

Source-Specific Modeling Protocol Summary Report 4- 5 4.3 CLAMET METEOROLOGICAL MODELING

No CALMET modeling was completed since VISTAS has p rovided the meteorological data used in the CALPUFF modeling. The CALMET modeling has already b een completed by the Earth Tech.

4.4 CALPUFF COMPUTATIONAL DOMAIN AND RECEPTORS

The computational domain is the same as the modelin g domain as indicated above. The CALPUFF model included the Class I receptors for each site as taken from the National Park Service Website. T he website conversion program was used to convert the receptor set into Lambert Conformal Coordinates (LCC) for use in the CALPUFF model.

4.5 CALPUFF MODELING OPTIONS SELECTIONS

The CALPUFF model was run using model options liste d in Section 4.3.3 of the VISTA’s Final Protocol The following list discusses the primary option sel ections:

- The CALPUFF model configuration for the regional CALPUFF follow the recommended IWAQM guidance (EPA, 1998; Pages B-1 through B-8), except as noted below:
- CALPUFF domain configured to include the source a nd all Class I areas within 300km of the source plus 50km buffer zone in each direction. CALPUFF is recommended for all source-receptor distances to be considered in the B ART analyses.

- Chemical mechanism: MESOPUFF II module - Background ammonia concentration: In CALPUFF, use constant (0.5 ppb) value for ammonia.

- Puff representation: integrated puff sampling metho dology.
- Use IWAQM (EPA, 1998) default guidance, including Pasquill-Gifford dispersion coefficients.

- Ozone dataset – use observed ozone data for 2001- 2003 from CASTNet and AIRS stations. Only non-urban ozone stations should be used in the OZONE.DAT file. Monthly average ozone (backup) background values are to be computed based on daytime average ozone concentrations from the OZONE.DAT file (6am-6pm ave rage ozone concentrations computed by month).BART Exemption Summary Report October, 2006

PCS Nitrogen. – Augusta, GA MACTEC Project No. 6306-06-0034

Source-Specific Modeling Protocol Summary Report 4- 6 4.6 LIGHT EXTINCTION AND HAZE IMPACT CALCULATIONS

The light extinction and haze impact calculations w ere computed using the CALPUFF post processor CALPOST adhering to the model options listed in Sec tion 4.3.3 of the VISTAs Final Protocol. The major options listed as follows:.

- Species considered in visibility analysis: SO4, NO3, soil, fine PM, NH 3 (modeled as NO 3 )
- Natural background light extinction: calculated b y CALPOST under Method 6, based on annual average default natural conditions component concen trations and monthly average f(RH) values for the Class I area taken from the FLAG document. , from Table A-3 in the natural conditions guidance document, - Light extinction efficiencies: Use of EPA (2003a ) values.BART Exemption Summary Report October, 2006

PCS Nitrogen. – Augusta, GA MACTEC Project No. 6306-06-0034

Source-Specific Modeling Protocol Summary Report 4- 7 4.7 MODELING RESULTS

Table 6 summarizes the output of the CALPOSTL model ing results for 12 Km domain.

Table 6 Modeling Results for 12 Km grid

This table demonstrates that of the eight Class I a reas, seven are not have significantly impacted by PCS emissions. The remaining Class I area (Cape Romain) was further evaluated using a 4-Km Met Grid spacing for comparison of the 98 th percentile or 8 th

highest value to the 0.5 DV value. Table 7 provide s the 4-Km modeling results which demonstrate that al l 8 th highest values are well below 0.5 DV.

Modeling Results in Deciview

(DV)

Site/ Class I Area Shortest Distance to PCS (km) 20 01 2002 2003

PCS -- - - -

Cape Romaine 220 0.457 0.596 0.571

Cohutta 288 0.269 0.175 0.409

Wolf Island 238 0.236 0.283 0.294

Great Smokey Mountains 258 0.209 0.153 0.163

Joyce Kilmer 280 0.120 0.154 0.175

Shining Rock Wilderness 225 0.362 0.238 0.220

Okefenokee 267 0.269 0.366 0.393

Linville Gorge 263 0.490 0.248 0.393BART Exemption Summary Report October, 2006

PCS Nitrogen. – Augusta, GA MACTEC Project No. 6306-06-0034

Source-Specific Modeling Protocol Summary Report 4- 8 Table 7 Modeling results for 4-Km grid

Class I Area Model Year 1 st High (DV) 8 th High

(DV)

Cape Romaine 2001 0.492 0.196

Cape Romaine 2002 0.417 0.250

Cape Romaine 2003 0.571 0.359BART Exemption Summary Report October, 2006

PCS Nitrogen. – Augusta, GA MACTEC Project No. 6306-06-0034

Source-Specific Modeling Protocol Summary Report 5- 1 5. SUMMARY

Based on the modeling results provided in Tables 6 and 7, it can be concluded that PCS does not have a significant visibility impairment on any Class I ar ea and can be excluded from further BART analysis. This modeling was completed under very conservative assumptions:

1) All ammonia reacts to form ammonium sulfate or n itrate,

2) All particulate emitted from the site is fine pa rticulate with a β extinction value of 1.0 and

3) Includes emissions from the facilities boilers w hich just provide steam to the BART eligible units.

4) Includes highest emissions from different days f or each emission unit instead of the single highest emission day.

Even with these conservative assumptions the modeli ng clearly demonstrates that visibility impacts on all Class I areas are insignificant (<0.5 DV). PCS ther efore plans no further submittals regarding this BA RT
rule.BART Exemption Summary Report October, 2006

PCS Nitrogen. – Augusta, GA MACTEC Project No. 6306-06-0034

6. REFERENCES

Protocol for the Application of the CALPUFF Model f or Analyses of Best Available Retrofit Technology (BART)” December 22, 2005 revised March 9 th , 2006.

Federal Land Managers’ Air Quality Related Values W orkgroup (FLAG) Phase I report (December 2000).BART Exemption Summary Report October, 2006

PCS Nitrogen. – Augusta, GA MACTEC Project No. 6306-06-0034

EXHIBIT A