Georgia's State Implementation Plan 

For 

Regional Haze 

January 25, 2010 

Prepared by: 

Georgia Department of Natural Resources 

Environmental Protection Division 

Air Protection Branch
This page is left intentionally blank. 
Georgia Regional Haze State Implementation Plan 

Preface: This document contains summaries of the technical analyses that will be 

used by Georgia Environmental Protection Division (GA EPD) to support the Regional 

Haze State Implementation Plan pursuant to §§169(A) of the Clean Air Act, as 

amended. 
Georgia Regional Haze State Implementation Plan 

i 

EXECUTIVE SUMMARY 

INTRODUCTION 

Regional haze, pollution that impairs the visibility over a large region, can adversely 

impact human health, especially respiratory and cardiovascular systems. Regional 

haze is caused by sources and activities emitting primarily fine particles and those 

precursors to particle pollution - sulfur dioxides (SO2), nitrogen oxides (NOx), ammonia 

(NH3) and volatile organic compounds (VOC). These fine particles and precursors are 

often transported over large regions, impairing visibility in national parks, forests, and 

wilderness areas including those areas termed “Class I” areas. 

Fine particles, similar in size to the wavelength of light, affect visibility through the 

scattering and absorption of light. This is called light extinction, the result of which is a 

hazy condition. Light extinction is one method of measuring visibility. Another is visual 

range. Visual range is the greatest distance, in kilometers or miles, at which a dark 

object can be viewed against the sky. The measure of visibility used by the Regional 

Haze Rule (RHR) is the deciview (dv) which is calculated directly from light extinction 

using a logarithmic scale. The deciview can also be used to express linear changes in 

visibility impairment that correspond to visual range. Therefore, higher deciview levels 

are hazier, while lower deciview levels are cleaner. 

Reducing fine particles in the atmosphere is generally considered to be an effective 

method of reducing regional haze, and thus, improving visibility.

REGULATORY HISTORY AND REGIONAL HAZE IN GEORGIA 

Section 169A of the 1977 Amendments to the Clean Air Act (CAA) set forth a program 

for protecting visibility in Federal Class I areas. It called for the “prevention of any 

future, and the remedying of any existing, impairment of visibility in mandatory Class I 

Federal areas which impairment results from manmade air pollution.” On December 2, 

1980, the United States Environmental Protection Agency (US EPA) promulgated 

regulations to address visibility impairment (45 FR 80084) that is “reasonably 

attributable” to a single source or small group of sources. Then, in the 1990 

Amendments to the CAA, Congress added Section 169B and called on the US EPA to 

issue regional haze rules. The Regional Haze Rule that the US EPA promulgated on 

July 1, 1999 (64 FR 35713), revised the existing visibility regulations in order to 

integrate provisions addressing regional haze impairment and to establish a 

comprehensive visibility protection program for Class I Federal areas. On July 6, 2005, 

the US EPA published a revised final rule, including Appendix Y to 40 CFR Part 51, The 

Guidelines for BART Determinations Under the Regional Haze Rule. 

The regional haze rule requires states to demonstrate reasonable progress toward 

meeting the national goal of a return to natural visibility conditions by 2064. The rule 

directs states to graphically show what would be a “uniform rate of progress,” also 

known as the “glide path,” toward natural conditions for each Class I area within the 
Georgia Regional Haze State Implementation Plan 

ii 

states and certain ones outside the states. The table below displays the natural visibility 

conditions for the most impaired and least impaired days for Georgia’s Class I areas. 

Natural Visibility Conditions for Georgia Class I Areas 

Natural Background Visibility Conditions 

Class I Area Average for 20 percent 

Worst Days 

(deciviews) 

Average for 20 percent 

Best Days 

(deciviews)

Cohutta Wilderness Area 10.78 4.32 

Okefenokee Wilderness 11.21 5.31 

Wolf Island 11.21 5.31 

Georgia has three Class I areas within its borders: Cohutta Wilderness Area, 

Okefenokee Wilderness Area and Wolf Island Wilderness Area, as designated in 

40CFR Part 81 Subpart 408 where visibility has been determined to be an important 

value. The Georgia Environmental Protection Division (GA EPD) is responsible for 

establishing reasonable progress goals for visibility improvement at each of these Class 

I areas, and a long-term strategy that will achieve those reasonable progress goals 

within the first regional haze planning period ending in 2018. 

This SIP includes Georgia’s reasonable progress goals, expressed in deciviews, for 

visibility improvement at each affected Class I area for the first 10-year period until 

2064, and must include determinations of the baseline visibility conditions (expressed in 

deciviews) for the most impaired and least impaired days. The table below displays the 

baseline conditions for Georgia’s Class I areas. 

Baseline Conditions for Georgia Class I Areas 

Baseline Visibility Conditions 2000-2004 

Class I Area Average for 20 percent 

Worst Days 

(deciviews) 

Average for 20 percent 

Best Days 

(deciviews)

Cohutta Wilderness Area 30.25 13.77 

Okefenokee Wilderness 27.13 15.23 

Wolf Island1 27.13 15.23 

The 20 percent worst visibility days at the Cohutta Wilderness generally occur in the 

period between April and September. The peak hazy days occur in the summer under 

stagnant weather conditions with high relative humidity, high temperatures, and low 

wind speeds. The 20 percent best visibility days can occur at any time of year. At Wolf 

Island, Okefenokee Wilderness Area and other coastal sites, the 20 percent worst and 

best visibility days are distributed throughout the year. 

 

1 There is no visibility monitor located at Wolf Island. Visibility at Wolf Island is assumed to be the same 

as the nearest Class I area, Okefenokee Wilderness. 
Georgia Regional Haze State Implementation Plan 

iii 

States must include a monitoring strategy for measuring, characterizing, and reporting 

of regional haze visibility impairment in their SIP. The long-term strategy includes 

enforceable emissions limitations, compliance schedules, and other measures as 

necessary to achieve the reasonable progress goals. States must also consider 

ongoing control programs, measures to mitigate construction activities, source 

retirement and replacement schedules, smoke management techniques for agriculture 

and forestry, and enforceability of specific measures. In developing this SIP, we have 

also considered that emission sources outside of Georgia may affect visibility at these 

Georgia Class I areas, and emission sources within Georgia that may affect visibility at 

Class I areas in neighboring states. 

In addition, a specific component of each state’s first long-term strategy is dictated by 

the Best Available Retrofit Technology (BART) requirements in 40 CFR 51.308(e) of the 

RHR. The RHR at §51.308(e) requires states to include a determination of BART for 

each BART-eligible source in the State that emits any air pollutant which may 

reasonably be anticipated to cause or contribute to any impairment of visibility in any 

mandatory Class I Federal area. 

The SIPs for the first review period were due December 17, 2007. These plans cover 

long-term strategies for visibility improvement between baseline conditions in 2000-

2004 and 2018. States are required to evaluate progress toward reasonable progress 

goals every five years to assure that installed emission controls are on track with 

emission reduction forecasts in each state implementation plan. 

CONTROLS APPLIED 

There are significant control programs being implemented between the baseline period 

and 2018. These programs will all reduce the particulate precursor emissions that 

affect visibility in the Class I areas. 

Federal control measures include the Clean Air Interstate Rule, NOx reductions from 

Federal Ozone Measures (NOx SIP Call), motor vehicle emission and fuel standards 

(e.g., Tiers 0, 1, and 2 emission standards and fuel sulfur requirements), and non-road 

engines and vehicle emission standards.

State control measures include existing NOx RACT measures, the Atlanta 1-Hour 

Ozone SIP, and the new Georgia Rule 391-3-1-.02(2)(sss) Multi-Pollutant Control for 

Electric Utility Generating Units that establishes a schedule for the installation and 

operation of NOx and sulfur dioxide pollution control systems on many of the coal-fired 

power plants in Georgia. Since the metro Atlanta region is also designated nonattainment for the Federal PM2.5 standards and the 8-hour ozone standard, control 

strategies for PM2.5 and ozone will be integrated into modeling for this SIP to the extent 

possible. 
Georgia Regional Haze State Implementation Plan 

iv 

BART control measures required by the RHR include a BART determination for 

Interstate Paper in Riceboro, Georgia. This facility will be required to use only natural 

gas for the Power Boiler (F1) at the facility except during periods of natural gas 

curtailment. 

Reasonable progress goals prompted GA EPD to consider what additional control 

measures would be reasonable. It was determined that SO2 emission reductions from 

electric generating units (EGUs) and non-EGU point sources in the VISTAS states 

would be the most effective sources to control to improve visibility at the Georgia Class I 

areas and non-Georgia Class I areas impacted by Georgia sources. Our review was 

conducted in a “top down” fashion starting with an analysis of the major source 

categories in each SO2 Area of Influence to determine which major categories had the 

highest residual contribution to the area in 2018. The regional haze rule requires that 

states consider the following four factors and demonstrate how these factors were taken 

into consideration in selecting the reasonable progress goal: 

• Costs of compliance 

• Time necessary for compliance 

• Energy and non-air quality environmental impacts of compliance, and 

• Remaining useful life of any potentially affected sources.

Georgia EPD requested four-factor analyses from SO2 point sources for emissions 

units identified as likely to contribute 0.5% or more to the total visibility impairment 

caused by sulfate at any Class I area in 2018. Analyses were received for a total of 15 

emissions units. For some emissions units additional data was submitted at the request 

of EPD or at the initiative of the facility. The submittals have been retained with Georgia 

EPD’s Regional Haze files. They are available to the public for inspection during normal 

business hours of 8:00 a.m. to 4:30 p.m. at the Georgia EPD, Air Protection Branch, 

4244 International Parkway, Suite 120, Atlanta, Georgia 30354. 

Three facilities requested limits on their affected emissions units in lieu of performing 

four-factor analyses: Rayonier Performance Fibers, Packaging Corporation of America, 

and Southern States Phosphate and Fertilizer. The requested limits dropped the sulfate 

contributions of these units below 0.5 percent of the total sulfate impact on any affected 

Class I areas. Of those performing the four-factor analysis, GA EPD is requiring 

lower SO2 limits for three of the facilities: Georgia Pacific’s Brunswick Cellulose 

facility, Georgia Pacific’s Cedar Springs Operation, and International Paper’s 

Savannah Mill.
Georgia Regional Haze State Implementation Plan 

v 

Control measures implemented by other states include measures such as the North Carolina 

Clean Smokestacks Act, consent agreements with Tampa Electric, Virginia Electric and Power 

Company, Gulf Power and American Electric Power, one-hour ozone SIPs submitted by 

Birmingham and Northern Kentucky, and NOx RACT in 8-hour non-attainment area SIPs. 

CONCLUSION 

In accordance with the requirements of 40 CFR §51.308(d)(1), this Regional Haze 

Implementation Plan establishes reasonable progress goals for each Class I area in 

Georgia. To calculate the rate of progress represented by each reasonable progress 

goal, GA EPD compared baseline visibility conditions to natural visibility conditions in 

each Class I area and determined the uniform rate of visibility improvement (in 

deciviews) that would need to be maintained during each implementation period in order 

to attain natural visibility conditions by 2064. Georgia EPD summarized expected 

visibility improvements under existing Federal and State regulations, BART 

determinations in Georgia and neighboring states, and any additional control measures 

found to be reasonable to implement in this review period. These controls were 

modeled in CMAQ as part of the long-term strategy. The modeling results were used to 

set reasonable progress goals. The tables below display Georgia’s 2018 reasonable 

progress goals for the 20 percent worst days and the 20 percent best days. Since the 

Okefenokee Wilderness and Wolf Island reasonable progress goals show a slower rate 

of improvement in visibility than the rate that would be needed to attain natural 

conditions by 2064 (uniform rate of progress glide slope), it has been estimated that an 

additional 6-7 years are needed to attain natural conditions. 

Georgia Reasonable Progress Goals – 20 Percent Worst Days 

Class I 

Area 

2004 

Baseline 

Visibility (dv) 

2018 Reasonable 

Progress Goal 

(dv) 

[2004 – 2018 

decrease] 

2018 Uniform 

Rate of Progress 

Glide Slope (dv) 

[2004 – 2018 

decrease to meet 

uniform progress] 

Natural 

Visibility (dv) 

 

 [2018-2064 

decrease 

needed from 

2018 goal] 

Cohutta 

Wilderness 

30.25 22.78 

[7.47] 

25.71 

[4.54] 

10.78 

[12.00] 

Okefenokee 

Wilderness 

27.13 23.77 

[3.36] 

23.42 

[3.71] 

11.21 

[12.56] 

Wolf Island 27.13 23.77 

[3.36] 

23.42 

[3.71] 

11.21 

[12.56] 
Georgia Regional Haze State Implementation Plan 

vi 

Class I 

Area 

2004 

Baseline 

Visibility (dv) 

2018 Reasonable 

Progress Goal 

(dv) 

[2004 – 2018 

decrease] 

2018 Uniform 

Rate of Progress 

Glide Slope (dv) 

[2004 – 2018 

decrease to meet 

uniform progress] 

Natural 

Visibility (dv) 

 

 [2018-2064 

decrease 

needed from 

2018 goal] 

Georgia Reasonable Progress Goals – 20 Percent Best Days 

Class I 

Area 

2004 and 2018 

Baseline Visibility (dv) 

2018 Reasonable Progress 

Goal (dv) 

[2004 – 2018 improvement 

goal] 

Cohutta 

Wilderness 

13.77 11.75 

[2.02] 

Okefenokee 

Wilderness 

15.23 13.92 

[1.31] 

Wolf Island 15.23 13.92 

[1.31] 

 
Georgia Regional Haze State Implementation Plan 

vii 

TABLE OF CONTENTS 

EXECUTIVE SUMMARY ............................................................................................................. i 

INTRODUCTION........................................................................................................................... i 

REGULATORY HISTORY AND REGIONAL HAZE IN GEORGIA....................................... i 

CONTROLS APPLIED......................................................................................................iii 

LIST OF APPENDICES............................................................................................................... x 

LIST OF FIGURES....................................................................................................................xiii 

LIST OF TABLES...................................................................................................................... xvi 

1.0 INTRODUCTION ................................................................................................................... 1 

1.1 Description of Regional Haze.......................................................................................... 1 

1.2 Clean Air Act Requirements for Addressing Regional Haze ...................................... 1 

1.3 General Overview of Regional Haze SIP Requirements ............................................ 2 

1.4 Class I Areas in Georgia .................................................................................................. 4 

1.5 State and Federal Land Manager Coordination ........................................................... 6 

1.6 Supporting Documentation for the SIP ......................................................................... 9 

2.0 ASSESSMENT OF BASELINE AND CURRENT CONDITIONS AND ESTIMATE OF 

NATURAL BACKGROUND CONDITIONS IN CLASS I AREAS ............................... 10 

2.1 Estimating Natural Conditions for Georgia Class I Areas ......................................... 11 

2.2 Estimating Baseline Conditions for Georgia Class I Areas....................................... 12 

2.3 Summary of Natural Background and Baseline Conditions for Georgia Class I 

Areas................................................................................................................................ 12 

2.4 Pollutant Contributions to Visibility Impairment (2000-2004 Baseline Data) ......... 13 

3.0 GLIDEPATHS FOR CLASS I AREAS IN GEORGIA..................................................... 18 

4.0 NATURE OF THE PROBLEM: CHIEF CAUSES OF VISIBILITY IMPAIRMENT IN 

GEORGIA CLASS I AREAS ............................................................................................ 20 

4.1 Baseline Emissions Inventory........................................................................................ 20 

4.1.1 Stationary Point Sources....................................................................................... 21 

4.1.2 Stationary Area Sources........................................................................................ 22 

4.1.3 Off-Road Mobile Sources...................................................................................... 23 

4.1.4 Highway Mobile Sources....................................................................................... 23 

4.1.5 Biogenic Emission Sources .................................................................................. 23 

4.1.6 Model Performance Improvements through Emissions Inventory 

Improvements ................................................................................................................ 24 
Georgia Regional Haze State Implementation Plan 

viii 

4.1.7 Summary 2002 Base G2 Baseline Emissions Inventory for Georgia............. 24 

4.2 Assessment of Relative Contributions from Specific Pollutants and Sources 

Categories....................................................................................................................... 25 

5.0 REGIONAL HAZE MODELING METHODS AND INPUTS........................................... 26 

5.1 Analysis Method .............................................................................................................. 26 

5.2 Model Selection ............................................................................................................... 27 

5.2.1 Selection of Photochemical Grid Model.............................................................. 27 

5.2.2 Selection of Meteorological Model....................................................................... 28 

5.2.3 Selection of Emissions Processing System ....................................................... 29 

5.3 Selection of the Modeling Year ..................................................................................... 31 

5.4 Modeling Domains........................................................................................................... 32 

5.4.1 Horizontal Modeling Domain................................................................................. 32 

5.4.2 Vertical Modeling Domain ..................................................................................... 34 

6.0 MODEL PERFORMANCE EVALUATION....................................................................... 35 

6.1 Modeling Performance Goals, and Criteria ................................................................. 36 

6.2 VISTAS Domain - Wide Performance.......................................................................... 37 

6.3 Georgia Class I Areas Performance............................................................................. 41 

7.0 LONG-TERM STRATEGY FOR GEORGIA CLASS I AREAS..................................... 45 

7.1 Overview of the Long-Term Strategy Development Process ................................... 45 

7.2 Expected Visibility Results in 2018 for Georgia Class I Areas under existing and 

planned emissions controls (Base G4 Inventory)..................................................... 46 

7.2.1 Federal and State Control Requirements ........................................................... 46 

7.2.2 Additional State Programs to Reduce Emissions.............................................. 47 

7.2.3 Projected 2009 and 2018 Base G4 Emissions Inventories.............................. 47 

7.2.4 Model Results for the 2018 Base G4 Inventory Compared to the Uniform 

Rate of Progress Glidepaths for Georgia Class I Areas.......................................... 50 

7.3 Relative Contribution from International Emissions to Visibility Impairment in 2018 

at VISTAS Class I Areas .............................................................................................. 57 

7.4 Relative Contributions to Visibility Impairment: Pollutants, Source Categories, and 

Geographic Areas.......................................................................................................... 61 

7.5 Relative Contributions to Visibility Impairment: Geographic Areas of Influence for 

Georgia Class I Areas................................................................................................... 65 

7.5.1 Back Trajectory Analyses...................................................................................... 65 

7.5.2 Residence Time Plots ............................................................................................ 66 

7.5.3 SO2 Areas of Influence.......................................................................................... 67 

7.5.4 Emissions Sources within SO2 Areas of Influence ........................................... 68 

7.5.5 Specific Source Types in the Areas of Influence for Georgia Class I Areas. 72 

7.6 Reasonable Progress Determinations for Individual Sources.................................. 76 
Georgia Regional Haze State Implementation Plan 

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7.6.1 Process for Determining Reasonable Progress ................................................ 76 

7.6.2 Sources Eligible for Four Factor Analysis in Georgia....................................... 79 

7.6.3 Regional Haze Reasonable Progress Four-Factor Analysis ........................... 81 

7.6.4 Required Controls for Sources Subject to Four-Factor Analysis in Georgia ...... 91 

7.7 Control Determinations Representing Best Available Retrofit Technology (BART) 

for Individual Sources.................................................................................................. 100 

7.7.1 BART-Eligible Sources in Georgia..................................................................... 101 

7.7.2 Determination of Sources Subject to BART in Georgia.................................. 102 

7.7.3 BART Determination for Subject-to-BART Sources........................................ 107 

7.8 What Additional Emissions Controls Were Considered as Part of the Long-Term 

Strategy for Visibility Improvement by 2018?.......................................................... 110 

8.0 REASONABLE PROGRESS GOALS............................................................................ 111 

9.0 MONITORING STRATEGY............................................................................................. 114 

10.0 INTERSTATE CONSULTATION .................................................................................. 118 

11.0 COMPREHENSIVE PERIODIC IMPLEMENTATION PLAN REVISIONS............. 121 

12.0 DETERMINATION OF ADEQUACY OF THE EXISTING PLAN ............................. 123 

13.0 COORDINATION WITH FEDERAL LAND MANAGERS.......................................... 123 
Georgia Regional Haze State Implementation Plan 

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LIST OF APPENDICES 

Appendix A: VISTAS Bylaws and Memorandum of Understanding 

Appendix B: VISTAS Conceptual Description Support Document 

 Subappendices to Appendix B 

• A. Nephelometer Comparisons 

• B. Original and Revised Algorithm Comparisons by Site 

• C. File Key for Substituted Data 

• D. Data Substitution Results for Individual Sites 

• E. Extinction Trend Charts (Mm-1, DV and SVR) 

• F. WinHaze Images (Baseline, 2018 and Natural Conditions) 

• G. 2000-2004 Timelines 

• H. DV Glidepaths 

• I. Speciated Glidepaths 

• J. Back Trajectory Maps 

• K. Residence Time Maps 

• L. International Attribution Plots 

Appendix B.1:Twenty Percent Best and Worst Visibility Days, 2000 – 2004: Okefenokee 

and Cohutta 

Appendix C: Emissions Preparation and Results 

Appendix D: Modeling Analysis Protocol and Quality Assurance Project Plan 

Appendix E: VISTAS Technical Support Document (with Subappendices A – H) 

Appendix F: Model Performance Evaluation 

Appendix G: EPA Modeling Guidance 
Georgia Regional Haze State Implementation Plan 

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Appendix H: Reasonable Progress Evaluation/Long Term Strategy 

 Subappendices to Appendix H 

• H.1 - Industrial Boiler/Process Heater/RICE MACT 

• H.2 - VISTAS Class I Statistics 

• H.3 - VISTAS Control Options Spreadsheet 

• H.4 - Letters to Facilities 

• H.5 - Emissions and Q/d for Georgia's BART Eligible sources 

• H.6 - BART VOC, NH3, and Primary PM Sensitivity Modeling 

• H.7 - BART Modeling Protocols 

• H.8 - BART Determination Submittals 

• H.9 - Correspondence Regarding Use of New IMPROVE Equation 

• H.10 - Supporting Data for Four-factor Analyses 

• H.11 - Comparison between Original and Revised Improve Equation 

Appendix I: GEOS-CHEM Report 

Appendix J: Interstate Consultation Process 

Appendix K: Recommended Improvements 

Appendix L: Characterization of Meteorology in the VISTAS Region 

Appendix M: Permit Conditions for Sources Subject to Additional BART or 

Reasonable Progress Requirements 

Appendix N: CMAQ Modeling for Reasonable Progress and BART Controls 

Appendix O: Federal Land Manager Consultation 

• O.1 – FWS and NPS Comments on Draft Prehearing SIP 

• O.2 – USFS Comments on Draft Prehearing SIP 
Georgia Regional Haze State Implementation Plan 

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• O.3 - EPD Responses to FLM Comments on Draft Prehearing SIP 

Appendix P: BART Model Plant Criteria with PM
Georgia Regional Haze State Implementation Plan 

xiii 

LIST OF FIGURES 

Figure 1.2-1. Geographical Areas of Regional Planning Organizations .................................................. 2 

Figure 1.4-1. Georgia Class I areas .................................................................................................... 5 

Figure 1.5-1. Class I Areas in the VISTAS Region............................................................................... 7 

Figure 1.5-2. Mandatory Class I Federal Areas in the VISTAS Region Where Visibility is an Important 

Value ................................................................................................................................................ 8 

Figure 2.4-1. Average light extinction for the 20 percent Haziest Days in 2000-2004 at VISTAS and 

neighboring Class I areas using New IMPROVE equation .................................................................. 14 

Figure 2.4-2. Average light extinction for the 20 percent Clearest Days in 2000-2004 at VISTAS and 

neighboring Class I areas using New IMPROVE equation .................................................................. 14 

Figure 3.1-1. Uniform Rate of Progress Glidepath for 20 percent worst days at Cohutta Wilderness Area

....................................................................................................................................................... 18 

Figure 3.1-2. Uniform Rate of Progress Glidepath for 20 percent worst days at Okefenokee Wilderness 

Area ............................................................................................................................................... 19 

Figure 4.2-1. SO2 emissions in 2002 in the VISTAS States. ............................................................... 25 

Figure 5.4.1-1. The MM5 horizontal domain is the outer most, blue grid, with the CMAQ 36-km domain 

nested in the MM5 domain. .............................................................................................................. 33 

Figure 5.4.1-2. A more detailed view of the 12-km grid over the VISTAS region. .................................. 34 

Figure 6.0-1: Monitoring Networks used for VISTAS 2002 model performance evaluation, and their 

location within the VISTAS 12km domain. ......................................................................................... 35 

Figure 6.2-1.: Soccer plot depicting both the mean fractional error and fractional bias for component 

concentration for all VISTAS sites based on Base G2 results. Each point represents a monthly value as 

compared to the model performance criteria (red box) and modeling performance goals (green box). ... 38 

Figure 6.2-2.: A zoomed view of the soccer plot depicting both the mean fractional error and fractional 

bias for component concentration for all VISTAS sites based on Base G2 results. Each point represents 

a monthly value as compared to the model performance criteria (red box) and modeling performance 

goals (green box)............................................................................................................................. 38 

Figure 6.2-3.: Seasonal soccer plots based on Base G1 results for all VISTAS IMPROVE monitors. ..... 39 

Figure 6.2-4.: Bugle plot of the mean fraction error for particulate matter and its component 

concentrations for all VISTAS sites based on Base G2 results. Each point represents a monthly mean 

fraction error value as compared to the model performance criteria (red lines) and modeling performance 

goals (green lines). .......................................................................................................................... 40 

Figure 6.2-5.: Bugle plot of mean fraction bias for particulate matter and its component species for all 

VISTAS sites based on Base G2 results. Each point represents a monthly mean fraction bias value as 

compared to the model performance criteria (red lines) and modeling performance goals (green lines). 40 

Figure 6.3-1.: Stacked bar chart for COHU on the 20% best days (top) and 20% worst days (bottom). 

Observed composition is presented in the left hand bar, with modeled composition represented by the 

right hand bar. ................................................................................................................................. 43 
Georgia Regional Haze State Implementation Plan 

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Figure 6.3-2.: Stacked bar chart for OKEF on the 20% best days (top) and 20% worst days (bottom). 

Observed composition is presented in the left hand bar, with modeled composition represented by the 

right hand bar. ................................................................................................................................. 44 

Figure 7.2.3-1. Base G Annual SO2 emissions for 2002, 2009, and 2018 in the VISTAS states. ........... 49 

Figure 7.2.3-2. Base G Annual NOx emissions in 2002, 2009, and 2018 in the VISTAS States. ............ 49 

Figure 7.2.4-1. CMAQ 2018 Base G4 results compared to Uniform Rate of Progress at Cohutta 

Wilderness Area .............................................................................................................................. 51 

Figure 7.2.4-2. CMAQ 2018 Base G4 results compared to Uniform Rate of Progress at Okefenokee 

Wilderness Area .............................................................................................................................. 51 

Figure 7.2.4-3. CMAQ 2018 Base G4 results compared to Uniform Rate of Progress at wolf Island....... 52 

Figure 7.2.4-4. CMAQ 2018 Base G4 results at Cohutta Wilderness Area. .......................................... 52 

Figure 7.2.4-5. CMAQ 2018 Base G4 results at Okefenokee Wilderness Area. .................................... 53 

Figure 7.2.4-6. CMAQ 2018 Base G4 results at Wolf Island................................................................ 53 

Figure 7.2.4-7. Projected visibility improvement on 20 percent worst visibility days at VISTAS and 

neighboring Class I areas for the 2018 Base G4 CMAQ run ............................................................... 55 

Figure 7.2.4-8. Projected visibility improvement on 20 percent best visibility days at VISTAS and 

neighboring Class I areas for the 2018 Base G4 CMAQ run ............................................................... 55 

Figure 7.2.4-9. Visibility improvement on 20 percent haziest days at Cohutta Wilderness Area between 

2000-2004 baseline conditions (left) and 2018 Base G4 projected visibility (right). Image generated using 

WinHaze. ........................................................................................................................................ 56 

Figure 7.2.4-10. Projected visibility on 20 percent haziest days for natural background visibility conditions 

at Cohutta Wilderness Area. Image generated using WinHaze. ......................................................... 56 

Figure 7.3-1. Estimated international emissions contributions to sulfate at VISTAS and neighboring Class 

I areas. ........................................................................................................................................... 58 

Figure 7.3-2. PM component concentrations from US domestic sources on 20 percent worst visibility days 

in 2002 (left bars) and CMAQ-simulated international contributions (right bars) at Cohutta Wilderness 

Area, GA......................................................................................................................................... 59 

Figure 7.3-3. Accounting for international emissions contributions on modeled rate of progress by 2018 at 

Cohutta, GA. Open triangle = estimate with all emissions; Open diamond = estimate with international 

emissions removed.......................................................................................................................... 60 

Figure 7.3-4. PM component concentrations from US domestic sources on 20 percent worst visibility days 

in 2002 (left bars) and CMAQ-simulated international contributions (right bars) at Okefenokee Wilderness 

Area, GA......................................................................................................................................... 60 

Figure 7.3-5. Accounting for international emissions contributions on modeled rate of progress by 2018 at 

Okefenokee, GA. Open triangle = estimate with all emissions; Open diamond = estimate with 

international emissions removed....................................................................................................... 61 

Figure 7.4-1. CMAQ projections of visibility responses on 20 percent worst days at Cohutta Wilderness 

Area, GA to 30 percent reductions from the 2009 Base D inventory for visibility-reducing pollutants in 

different source categories and geographic areas. ............................................................................. 63 

Figure 7.4-2. CMAQ projections of visibility responses on 20 percent worst days at Okefenokee 

Wilderness Area, GA to 30 percent reductions from the 2009 Base D inventory for visibility-reducing 

pollutants in different source categories and geographic areas. .......................................................... 63 
Georgia Regional Haze State Implementation Plan 

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Figure 7.5.1-1. Example back trajectories for 20 percent worst visibility days in 2002 for Cohutta 

Wilderness Area. ............................................................................................................................. 66 

Figure 7.5.2-1. Example residence time plot for 20 percent worst visibility days in 2000-2004 for Cohutta 

Wilderness Area. Based on trajectories with 100m start height. .......................................................... 67 

Figure 7.5.3-1. Example SO2 Area of Influence plot for sulfate extinction weighted residence time for 20 

percent worst visibility days in 2000-2004 for Cohutta Wilderness Area, Georgia. Based on trajectories 

with 100m start height...................................................................................................................... 68 

Figure 7.5.4-1. Cohutta Wilderness Area 2002 and 2018 SO2 distance weighted emissions x SO4 

extinction-weighted residence time plots. .......................................................................................... 69 

Figure 7.5.4-2. 2018 SO2 distance weighted emissions x SO4 extinction-weighted residence time plot for 

Okefenokee, Georgia....................................................................................................................... 70 

Figure 7.6.4-1. Locations Of Facilities With Emission Units Eligible .................................................... 99 

Figure 7.7.3-1. Locations of facilities with BART-eligible emission units. ........................................... 109 

Figure 8.0-1. CMAQ 2018 Base G4 results compared to Uniform Rate of Progress at Cohutta Wilderness 

Area with GA Reasonable Progress Goals ...................................................................................... 113 

Figure 8.0-2. CMAQ 2018 Base G4 results compared to Uniform Rate of Progress at Okefenokee 

Wilderness Area with GA Reasonable Progress Goals..................................................................... 113 

Figure 9.0-1. PM2.5 Monitoring Network in Georgia ......................................................................... 116 
Georgia Regional Haze State Implementation Plan 

xvi 

LIST OF TABLES 

Natural Visibility Conditions for Georgia Class I Areas.......................................................... ii 

Baseline Conditions for Georgia Class I Areas ....................................................................... ii 

Georgia Reasonable Progress Goals – 20 Percent Worst Days.......................................... v 

Georgia Reasonable Progress Goals – 20 Percent Best Days ........................................... vi 

Table 2.3-1. Natural Background and Baseline Conditions for Georgia Class I Areas .. 13 

Table 4.1. 2002 Emissions Inventory Summary for GA in tons per year......................... 25 

Table 6.1-1.: Established model performance goals and criteria for the component 

species of fine particle mass. ................................................................................................... 36 

Table 7.2.3-1. 2009 Emissions Inventory Summary for Georgia. ...................................... 50 

Table 7.2.3-2. 2018 Emissions Inventory Summary for Georgia. ...................................... 50 

Table 7.5.4-1. 2018 SO2 Point Source Contribution (Using RTMax*Q/d) to Georgia 

Class I Areas by State............................................................................................................... 71 

Table 7.5.5-1. 2018 Emissions Contributions from Major Source Categories in the Area 

of Influence for Cohutta Wilderness Area. ............................................................................. 73 

Table 7.5.5-2. 2018 Emissions Contributions from Major Source Categories in the Area 

of Influence for Okefenokee Wilderness Area....................................................................... 73 

Table 7.5.5-3. 2018 Emissions Contributions from Major Source Categories in the Area 

of Influence for Wolf Island....................................................................................................... 74 

Table 7.5.5-4. 2018 SO2 Emissions Contributions from Major Source Categories in the 

Area of Influence for GA Class I areas................................................................................... 75 

Table 7.6.1-1. Projected 2018 SO2 emission reductions associated with planned 

reduction measures at Georgia Power EGUs. ...................................................................... 78 

Table 7.6.2-1. List of all facilities along with their units eligible for 4-factor analysis ...... 80 

Table 7.6.2-2. Units Removed from 4-Factor List Based on Facilities’ Updated 2018 

Emission Estimates.................................................................................................................... 81 

Table 7.6.2-3. Facilities That Requested Emission Limits................................................... 81 

Table 7.6.4-1. Summary of Required Emissions Limits for Sources Subject to FourFactor Analyses.......................................................................................................................... 93 

Table 7.6.4-2. Permit Limits for Implementation of Reasonable Progress Emissions 

Reductions .................................................................................................................................. 98 

Table 7.7.1-1. Facilities with BART-eligible sources in Georgia....................................... 101 

Table 7.7.2-1 Exemption modeling results for BART-eligible sources. ........................... 103 
Georgia Regional Haze State Implementation Plan 

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Table 7.7.2-2. Facilities exempted from BART via other methods................................... 106 

Table 7.7.3-1 BART determination results for subject-to BART sources........................ 108 

Table 8.0-1. Georgia Reasonable Progress Goals – 20 percent Worst Days................ 112 

Table 8.0-2. Georgia Reasonable Progress Goals – 20 percent Best Days.................. 112 

Table 9.0-1. Class I areas in Georgia and IMPROVE monitors that represent conditions 

at each of them......................................................................................................................... 115 

Table 10-1: Georgia point source contribution to Joyce Kilmer-Slickrock (NC)............. 119 

Table 10-2: Georgia point source contribution to Shining Rock (NC). ............................ 119 

Table 10-3: Georgia point source contribution to Great Smoky Mountains (NC/TN).... 119 

Table 10-4: Georgia point source contribution to Swanquarter (NC). ............................. 119 

Table 10-5: Georgia point source contribution to Sipsey Wildernesses (AL)................. 120 

Table 10-6: Georgia point source contribution to Cape Romain (SC)............................. 120 

Table 10-7: Georgia point source contribution to St. Marks (FL). .................................... 120 
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1.0 INTRODUCTION 

1.1 Description of Regional Haze 

Regional haze is pollution from disparate sources that impairs visibility over a large 

region, including national parks, forests, and wilderness areas [Federal “Class I” areas 

defined by 40CFR Part 51.301(o) and Part 81, Subpart D]. Regional haze is caused by 

sources and activities emitting fine particles and the precursors. Those emissions are 

often transported over large regions. 

Particles affect visibility through the scattering and absorption of light, and fine particles 

– particles similar in size to the wavelength of light – are most efficient, per unit of mass, 

at reducing visibility. Fine particles may either be emitted directly or formed from 

emissions of precursors, the most important of which are sulfur dioxides (SO2) and 

nitrogen oxides (NOx). Reducing fine particles in the atmosphere is generally 

considered to be an effective method of reducing regional haze, and thus improving 

visibility. Fine particles also adversely impact human health, especially respiratory and 

cardiovascular systems. The United States Environmental Protection Agency (USEPA) 

has set national ambient air quality standards for daily and annual levels of fine particles 

with diameter smaller than 2.5 μm (PM2.5). The most important sources of PM2.5 and 

its precursors are coal-fired power plants, industrial boilers and other combustion 

sources. Other significant contributors to PM2.5 and visibility impairment include mobile 

source emissions, area sources, fires, and wind blown dust. 

1.2 Clean Air Act Requirements for Addressing Regional Haze 

In Section 169A of the 1977 Amendments to the Clean Air Act (CAA), Congress set 

forth a program for protecting visibility in Federal Class I areas which calls for the 

“prevention of any future, and the remedying of any existing, impairment of visibility in 

mandatory Class I Federal areas which impairment results from manmade air pollution.” 

Congress adopted the visibility provisions to protect visibility in 156 national parks and 

wilderness areas. On December 2, 1980, US EPA promulgated regulations to address 

visibility impairment (45 FR 80084). The 1980 regulations were developed to address 

visibility impairment that is “reasonably attributable” to a single source or small group of 

sources. These regulations represented the first phase in addressing visibility 

impairment and deferred action on regional haze that emanates from a variety of 

sources until monitoring, modeling and scientific knowledge about the relationships 

between pollutants and visibility impairment improved. 

In the 1990 Amendments to the CAA, Congress added Section 169B and called on US 

EPA to issue regional haze rules. The Regional Haze Rule (RHR) that US EPA 

promulgated on July 1, 1999 (64 FR 35713), revised the existing visibility regulations in 

order to integrate provisions addressing regional haze impairment and establish a 

comprehensive visibility protection program for Class I Federal areas. States are 

required to submit state implementation plans (SIPs) to USEPA that set out each state’s 
Georgia Regional Haze State Implementation Plan 

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plan for complying with the regional haze rule, including consultation and coordination 

with other states and with Federal land managers. The timing of SIP submittal is tied to 

US EPA’s promulgation of designations for the National Ambient Air Quality Standard 

(NAAQS) for PM2.5. Regional Haze SIPs are due at the same time as PM2.5 SIPs are 

due under section 172 of Clean Air Act. Therefore, states must submit a regional haze 

implementation plan to USEPA within three years after the date of PM2.5 designations. 

Because USEPA promulgated designation dates on December 17, 2004, regional haze 

SIPs must be submitted by December 17, 2007. 

The regional haze rule addressed the combined visibility effects of various pollution 

sources over a wide geographic region. This wide-reaching pollution net meant that 

many states – even those without Class I Areas – would be required to participate in 

haze reduction efforts. US EPA designated five regional planning organizations (RPOs) 

to assist with the coordination and cooperation needed to address the visibility issue. 

Those states that make up the southeastern portion of the contiguous United States are 

known as VISTAS (Visibility Improvement – State and Tribal Association of the 

Southeast), and include the following states: Alabama, Florida, Georgia, Kentucky, 

Mississippi, North Carolina, South Carolina, Tennessee, Virginia, and West Virginia. 

Figure 1.2-1. Geographical Areas of Regional Planning Organizations 

1.3 General Overview of Regional Haze SIP Requirements 

The regional haze rule (RHR) at 51.308(d) requires states to demonstrate reasonable 

progress toward meeting the national goal of a return to natural visibility conditions by 

2064. As a guide for reasonable progress, the RHR directs states to graphically show 

what would be a “uniform rate of progress” toward natural conditions for each 

mandatory Class I Federal area within the State and/or for each mandatory Class I 

Federal area located outside the State, which may be affected by emissions from 

sources within the State. States are to establish baseline visibility conditions for 2000-
Georgia Regional Haze State Implementation Plan 

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2004, natural background visibility conditions in 2064, and the rate of uniform progress 

between baseline and background conditions. The uniform rate of progress is also 

known as the “glidepath.” 

The RHR then requires States to establish reasonable progress goals (RPGs), 

expressed in deciviews, for visibility improvement at each affected Class I area covering 

each (approximately) 10-year period until 2064. The goals must provide for reasonable 

progress towards achieving natural visibility conditions, provide for improvement in 

visibility for the most impaired days over the period of the implementation plan, and 

ensure no degradation in visibility for the least impaired days over the same period [see 

§51.308(d)(1)]. 

In order to ensure that visibility goals are properly met and set, state implementation 

plans must include determinations, for each Class I area, of the baseline visibility 

conditions for the most impaired and least impaired days. SIPs must also contain 

supporting documentation for all required analyses used to calculate the degree of 

visibility impairment under natural visibility conditions for the most impaired and least 

impaired days [see §51.308(d)(2)]. In addition, states must include a monitoring 

strategy for measuring, characterizing, and reporting of regional haze visibility 

impairment that is representative of all mandatory Class I Federal areas within the state 

[see §51.308(d)(4)].

This first set of reasonable progress goals must be met through measures contained in 

the state’s long-term strategy covering the period from the present until 2018. The longterm strategy includes enforceable emissions limitations, compliance schedules, and 

other measures as necessary to achieve the reasonable progress goals, including all 

controls required or expected under all Federal and State regulations by 2009 and by 

2018. During development of the long-term strategy, states are also required to 

consider specific factors such as the above-mentioned ongoing control programs, 

measures to mitigate construction activities, source retirement and replacement 

schedules, smoke management programs for agriculture and forestry, and enforceability 

of specific measures [see §51.308(d)(3)]. 

In addition, a specific component of each state’s first long-term strategy is dictated by 

the specific Best Available Retrofit Technology (BART) requirements in 40 CFR 

51.308(e) of the RHR. The RHR at §51.308(e) requires states to include a 

determination of BART for each BART-eligible source in the State that emits any air 

pollutant, which may reasonably be anticipated to cause or contribute to any impairment 

of visibility in any mandatory Class I Federal area. Clean Air Act Section 169A(b) 

defines BART-eligible sources as sources in 26 specific source categories in operation 

within a 15-year period prior to enactment of the 1977 Clean Air Act Amendments. 

States must determine BART according to five factors set out in Section 169A(g)(7) of 

the Clean Air Act. Emission limitations representing BART and schedules for 

compliance with BART for each source subject to BART must be included in the longterm strategy. 
Georgia Regional Haze State Implementation Plan 

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State Implementation Plans for the first review period are due December 17, 2007. 

These plans will cover long-term strategies for visibility improvement between baseline 

conditions in 2000-2004 and 2018. States are required to evaluate progress toward 

reasonable progress goals every five years to assure that installed emissions controls 

are on track with emissions reduction forecasts in each SIP. The first interim review 

would be due to US EPA in December of 2012. If emissions controls are not on track to 

meet SIP forecasts, then states would need to take action to assure emissions controls 

by 2018 will be consistent with the SIP or to revise the SIP to be consistent with the 

revised emissions forecast. 

1.4 Class I Areas in Georgia

Georgia has three Class I areas within its borders: Cohutta Wilderness Area, 

Okefenokee Wilderness Area and Wolf Island as designated in 40CFR Part 81 Subpart 

408 where visibility has been determined to be an important value. The Georgia 

Environmental Protection Division (GA EPD) in the Georgia Department of Natural 

Resources is responsible for developing the Regional Haze SIP. This SIP establishes 

reasonable progress goals for visibility improvement at each of these Class I areas, and 

a long-term strategy that will achieve those reasonable progress goals within the first 

regional haze planning period. 

In developing this SIP, we have also considered that emission sources outside of 

Georgia may affect visibility at these Georgia Class I areas, and emission sources 

within Georgia that may affect visibility at the following Class I areas in neighboring 

states. Through VISTAS, the southeastern states have worked together to assess 

state-by-state contributions to visibility impairment in specific class I areas, including 

those in GA and those affected by emissions from Georgia. This technical work is 

discussed further in chapters 5, 6, and 7 below. Consultations to date between Georgia 

and other states are summarized in Chapter 10. 

Visibility at the following class I areas in the neighboring states may be affected by 

emission sources with Georgia: 

• Cape Romain Wilderness Area, South Carolina 

• Linville Gorge Wilderness Area, North Carolina 

• Shining Rock Wilderness Area, North Carolina 

• Joyce Kilmer - Slick Rock Wilderness Area, North Carolina and Tennessee 

• Great Smoky Mountains, Tennessee, North Carolina 

• Sipsey Wilderness area, Alabama 

• St. Marks, Florida 

• Chassahowitzka, Florida 
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Figure 1.4-1. Georgia Class I areas 

Prior to VISTAS, the southern states cooperated in a voluntary regional partnership “to 

identify and recommend reasonable measures to remedy existing and prevent future 

adverse effects from human-induced air pollution on the air quality-related values of the 

Southern Appalachian Mountains.” States cooperated with Federal land managers, the 

Environmental Protection Agency, industry, environmental organizations and academia 

to complete a technical assessment of the impacts of acid deposition, ozone, and fine 

particles on sensitive resources in the Southern Appalachians. The Southern 

Appalachian Mountain Initiative (SAMI) Final Report was delivered in August of 2002. 

The SAMI Assessment concluded that ammonium sulfate is the major contributor to 

GEORGIA CLASS I AREAS
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visibility impairment in the Southern Appalachian Mountains and to improve visibility, it 

is most important to reduce sulfur dioxide emissions. SAMI also concluded that 

reducing ammonia emissions would be helpful to reduce ammonium nitrate 

contributions to visibility impairment. Emissions controls for organic carbon, elemental 

carbon, and soil were expected to be less important for improving visibility. SAMI 

modeling found that on the haziest days, much of the benefit of emissions reductions 

would occur in the state where emissions reductions were made. Emissions in 

surrounding SAMI states and states outside the SAMI region also contribute to air 

quality in the SAMI Class I areas. The SAMI states supported strong national multipollutant legislation to accomplish its mission. Emissions reductions to meet national 

health standards for ozone and fine particles were expected to also improve air quality 

in the Southern Appalachian Mountains. SAMI states committed to consider air quality 

benefits in the Southern Appalachians as they developed State Implementation Plans 

for the health standards. 

In 2004, US EPA promulgated the Clean Air Interstate Rule (CAIR) to require emissions 

reductions for sulfur dioxide and nitrogen dioxide from electric generating utilities in 26 

eastern states. The CAIR rule allows for interstate trading of emissions to find cost 

effective reductions. These reductions will improve visibility in Class I areas in Georgia. 

1.5 State and Federal Land Manager Coordination 

As required by 40 CFR §51.308(i), the regional haze SIP must include procedures for 

continuing consultation between the State of Georgia and Federal Land Managers 

(FLMs) on the implementation of the visibility protection program, including development 

and review of implementation plan revisions and 5-year progress reports, and on the 

implementation of other programs having the potential to contribute to impairment of 

visibility in any mandatory Class I Federal area within the State. Coordination with 

FLMs is described in more detail in Section 13. 

1.6 Interstate Consultation 

Successful implementation of a regional haze program will involve long-term regional 

coordination among states. VISTAS was formed in 2001 to address regional haze and 

visibility problems in the southeastern United States. Jurisdictions represented by 

VISTAS members include the Eastern Band of Cherokee Indians; the States of 

Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolina, South Carolina, 

Tennessee, Virginia, and West Virginia; and the local air pollution control programs 

located in these states. A copy of the VISTAS Bylaws and Memorandum of 

Understanding is enclosed as Appendix A. Interstate consultation is described in more 

detail in Section 10. 
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The objectives of the VISTAS project are to establish natural background visibility 

conditions across the mandatory Class I Federal areas, identify current visibility 

impairment levels, analyze emission control levels that will achieve interim visibility 

goals, and provide adequate documentation to member agencies so that they can 

develop their regional haze State/Tribal Implementation Plans (SIP/TIP). Figure 1.5-1 

shows the 18 mandatory Class I Federal areas in the VISTAS Region where visibility is 

an important value. Figure 1.5-2 lists these Class I areas.

Figure 1.5-1. Class I Areas in the VISTAS Region 
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Mandatory Class I Federal Areas in the VISTAS Region 

Where Visibility is an Important Value 

State Area Name Acreage Federal 

Land 

Manager 

40 CFR §81.401 Alabama Sipsey Wilderness 12,646 USDA-FS 

40 CFR §81.407 Florida Chassahowitzka Wilderness 23,360 USDI-FWS 

 Everglades National Park 1,397,429 USDI-NPS 

 St. Marks Wilderness 17,745 USDI-FWS 

40 CFR §81.408 Georgia Cohutta Wilderness 33,776 USDA-FS 

 Okefenokee Wilderness 343,850 USDI-FWS 

 Wolf Island Wilderness 5,126 USDI-FWS 

40 CFR §81.411 Kentucky Mammoth Cave National Park 51,303 USDI-NPS 

40 CFR §81.422 North 

Carolina 

Great Smoky Mountains National 

Park 

273,551 USDI-NPS 

 Joyce Kilmer-Slickrock Wilderness 10,201 USDA-FS 

 Linville Gorge Wilderness 7,575 USDA-FS 

 Shining Rock Wilderness 13,350 USDA-FS 

 Swanquarter Wilderness 9,000 USDI-FWS 

40 CFR §81.426 South 

Carolina 

Cape Romain Wilderness 28,000 USDI-FWS 

40 CFR §81.428 Tennessee Great Smoky Mountains National 

Park 

241,207 USDI-NPS 

 Joyce Kilmer-Slickrock Wilderness 3,832 USDA-FS 

40 CFR §81.433 Virginia James River Face Wilderness 8,703 USDA-FS 

 Shenandoah National Park 190,535 USDI-NPS 

40 CFR §81.435 West 

Virginia 

Dolly Sods Wilderness 10,215 USDA-FS 

 Otter Creek Wilderness 20,000 USDA-FS 

Figure 1.5-2. Mandatory Class I Federal Areas in the VISTAS Region Where Visibility is an 

Important Value 

A technical support document for the regional haze state implementation plans is 

contained in Appendix E. The report includes a review of the science and situation, 

calculation of initial baseline visibility, review of monitoring data/data gaps, and 

recommendations for additional monitoring, initial emission inventory characterization 

and projections, and compliance with existing control programs. Source contributions to 

VISTAS mandatory Class I Federal areas are also assessed. 
Georgia Regional Haze State Implementation Plan 

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1.6 Supporting Documentation for the SIP 

Supporting files and databases that would be impracticable to print are available 

electronically, both on the submitted CD-R and via permanent EPD web links. In 

addition, files are permanently archived on EPD computer networks. To request access 

to any of these files please contact the Georgia EPD Air Protection Branch at (404) 363-

7000.
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2.0 ASSESSMENT OF BASELINE AND CURRENT CONDITIONS AND 

ESTIMATE OF NATURAL BACKGROUND CONDITIONS IN CLASS I 

AREAS 

The goal of the Regional Haze Rule is to restore natural visibility conditions to the 156 

Class I areas identified in the 1977 Clean Air Act Amendments. Section 51.301(q) 

defines natural conditions: “Natural conditions include naturally occurring phenomena 

that reduce visibility as measured in terms of light extinction, visual range, contrast, or 

coloration.” The Regional Haze SIPs must contain measures that make “reasonable 

progress” toward this goal by reducing anthropogenic emissions that cause haze. 

An easily understood measure of visibility to most people is visual range. Visual range is 

the greatest distance, in kilometers or miles, at which a dark object can be viewed 

against the sky. For evaluating the relative contributions of pollutants to visibility 

impairment, however, the most useful measure of visibility impairment is light extinction, 

which is usually expressed in units of inverse megameters (Mm-1). Light extinction 

affects the clarity and color of objects being viewed. 

The measure used by the regional haze rule is the deciview (dv). Deciviews are 

calculated directly from light extinction using a logarithmic scale. The deciview is a 

useful measure for tracking progress in improving visibility because each deciview 

change is an equal incremental change in visibility perceived by the human eye. Most 

people can detect a change in visibility at one deciview. 

For each Class I area, there are three metrics of visibility that are part of the 

determination of reasonable progress: 

1) Natural conditions, 

2) Baseline conditions, and 

3) Current conditions. 

Each of the three metrics includes the concentration data of the visibility pollutants as 

different terms in the light extinction algorithm, with respective extinction coefficients 

and relative humidity factors. Total light extinction when converted to deciviews (dv) is 

calculated for the average of the 20 percent best and 20 percent worst visibility days. 

“Natural” visibility is determined by estimating the natural concentrations of visibility 

pollutants and then calculating total light extinction. “Baseline” visibility is the starting 

point for the improvement of visibility conditions. It is the average of the Interagency 

Monitoring of Protected Visual Environments (IMPROVE) monitoring data for 2000 

through 2004 and is equivalent to “current” visibility conditions for this initial review 

period. The comparison of initial baseline conditions to natural visibility conditions 

indicates the amount of improvement necessary to attain natural visibility by 2064. 

Each state must calculate baseline and natural visibility levels for Class I areas within its
Georgia Regional Haze State Implementation Plan 

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borders [51.308(d)(2)]. “Current conditions” are assessed every five years as part of the 

SIP review where actual progress in reducing visibility impairment is compared to the 

reductions committed to in the SIP. 

2.1 Estimating Natural Conditions for Georgia Class I Areas 

Natural background visibility, as defined in 2003 US EPA guidance, is based on annual 

average concentrations of fine particle components. The same annual average natural 

background visibility is assumed for all Class I areas in the eastern United States 

(separate values are estimated for the western United States). Natural background 

visibility for the 20 percent worst days is estimated by assuming that fine particle 

concentrations for natural background are normally distributed and the 90th percentile of 

the annual distribution represents natural background visibility on the 20 percent worst 

days. 

In the 2003 guidance, US EPA also provided that states may use a “refined approach” 

to estimate the values that characterize the natural visibility conditions of the Class I 

areas. The purpose of such a refinement would be to provide more accurate estimates 

with changes to the extinction algorithm that may include the concentration values, 

factors to calculate extinction from a measured particular species and particle size, the 

extinction coefficients for certain compounds, geographical variation (by altitude) of a 

fixed value, and the addition of visibility pollutants.

In 2005, the IMPROVE Steering Committee made recommendations for a refined 

equation that modifies the terms of the original equation to account for the most recent 

data. The choice between use of the old or the new equation for calculating the 

visibility metrics for each Class I area is made by the state in which the Class I area is 

located. 

 bext ≈ 2.2 x fS(RH) x [Small Sulfate] + 4.8 fL(RH) x [Large Sulfate] 

 + 2.4 x fS(RH) x [Small Nitrate] + 5.1 fL(RH) x [Large Nitrate] 

 + 2.8 x [Small Organic Mass] + 6.1 x [Large Organic Mass] 

 + 10 x [Elemental Carbon] 

 + 1 x [Fine Soil] 

 + 1.7 x fSS(RH) x [Sea Salt] 

 + 0.6 x [Course Mass] 

 + Rayleigh Scattering (Site Specific) 

 + 0.33 x [NO2(ppb)] 

The new IMPROVE equation accounts for the effect of particle size distribution on light 

extinction efficiency of sulfate, nitrate, and organic carbon hence the total sulfate, nitrate 

and organic carbon compound concentrations are each split into two fractions, 

representing small and large size distributions of those components. The mass 

multiplier for organic carbon (particulate organic matter) is increased from 1.4 to 1.8. 

New terms are added to the equation to account for light extinction by sea salt and light 

absorption by gaseous nitrogen dioxide. Site-specific values are used for Rayleigh 
Georgia Regional Haze State Implementation Plan 

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scattering to account for the site-specific effects of elevation and temperature. Separate 

relative humidity enhancement factors are used for small- and large-sized distributions 

of ammonium sulfate and ammonium nitrate and for sea salt. The elemental carbon 

(light-absorbing carbon), fine soil, and coarse mass terms do not change between the 

original and new IMPROVE equation. 

The VISTAS states chose to use the new IMPROVE equation as the basis for the 

conceptual description because it takes into account the most recent review of the 

science and because it is recommended by the IMPROVE Steering Committee. For 

more detailed discussion of the two IMPROVE equations, see Appendix B. 

Georgia EPD requested in writing (from Carol Couch to J.I. Palmer, dated August 19, 

2008) to use the new IMPROVE equation to calculate light extinction effects from two 

BART-eligible facilities: Georgia Pacific Cedar Springs and Georgia Power Plant 

Bowen. EPA Region IV approved this request in a letter dated September 11, 2008. 

2.2 Estimating Baseline Conditions for Georgia Class I Areas 

Baseline visibility conditions at each Georgia Class I area are estimated using sampling 

data collected at IMPROVE monitoring sites. A -5year average (2000 to 2004) was 

calculated for each of the 20 percent worst and 20 percent best visibility days in 

accordance with 40 CFR 51.308(d)(2) and the US EPA Guidance for Tracking Progress 

Under the Regional Haze Rule. IMPROVE data records for Okefenokee for the period 

2000 to 2004 meet US EPA requirements for data completeness (75 percent for the 

year and 50 percent for each quarter). Cohutta did not meet completeness criteria in 

2000, 2001, and 2003. Data records for 2001 and 2003 were filled using data 

substitution procedures outlined in Appendix B, but there was too little data in 2000 to 

perform data filling. IMPROVE does not operate a monitor at Wolf Island and considers 

the IMPROVE monitor at Okefenokee Wilderness Area to be representative of visibility 

at Wolf Island. The light extinction and deciview visibility values for the 20 percent 

worst and 20 percent best visibility days at the Class I areas are based on data and 

calculations included in Appendix B of this SIP. The 20 percent worst and 20 percent 

best visibility days with their respective extinction values are presented in Appendix B.1. 

2.3 Summary of Natural Background and Baseline Conditions for Georgia Class I 

Areas 

Table 2.3-1 presents estimated natural background and baseline visibility metrics for 

Georgia Class I areas. Note that Georgia is not considering international emissions to 

be a component of natural background. Baseline visibility on the 20 percent worst days 

at Cohutta Wilderness Area, Okefenokee Wilderness Area, and Wolf Island is generally 

between 27 and 30 dv. Natural background visibility at all three sites is predicted to be 

between 11 and 12 dv. The class I area with the worst visibility impairment is Cohutta 

Wilderness Area at greater than 30 dv on the 20 percent worst days. 
Georgia Regional Haze State Implementation Plan 

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Table 2.3-1. Natural Background and Baseline Conditions for Georgia Class I 

Areas 

Natural Background Conditions 

 Class 1 Area Average for 

20 percent 

Worst Days

(deciviews) 

Average for 

20 percent 

Best Days 

(deciviews) 

Average for 

20 percent 

Worst Days 

Bext (Mm-1) 

Average for 

20 percent 

Best Days 

Bext (Mm-1) 

Cohutta Wilderness Area 10.78 4.32 29.38 15.40 

Okefenokee Wilderness 11.21 5.31 30.67 16.99 

Wolf Island 11.21 5.31 30.67 16.99 

Baseline Visibility Conditions 2000-2004 

Class 1 Area Average for 

20 percent 

Worst Days

(deciviews) 

Average for 

20 percent 

Best Days 

(deciviews)

Bext (Mm-1) 

Average for 

20 percent 

Worst Days

Bext (Mm-1) 

Average for 

20 percent 

Best Days

Cohutta Wilderness Area 30.25 13.77 206.21 39.62 

Okefenokee Wilderness 27.13 15.23 151.50 45.85 

Wolf Island 27.13 15.23 151.40 45.85 

2.4 Pollutant Contributions to Visibility Impairment (2000-2004 Baseline Data) 

The 20 percent worst visibility days at the Southern Appalachian sites (in Georgia: only 

the Cohutta Wilderness Area is part of the Southern Appalachian sites) generally occur 

in the period April to September. The peak hazy days occur in the summer under 

stagnant weather conditions with high relative humidity, high temperatures, and low 

wind speeds. The 20 percent best visibility days at the Cohutta Wilderness Area can 

occur at any time of year. At Wolf Island, Okefenokee Wilderness Area and other 

coastal sites, the 20 percent worst and best visibility days are distributed throughout the 

year. 

Ammonium sulfate, (NH4)2SO4, is the most important contributor to visibility impairment 

and fine particle mass on the 20 percent worst and 20 percent best visibility days at all 

the Georgia Class I areas. Sulfate levels on the 20 percent worst days account for 60-

70 percent of the visibility impairment. Across the VISTAS region, sulfate levels are 

higher at the Southern Appalachian sites than at the coastal sites (Figure 2.4-1). On the 

20 percent clearest days, sulfate levels are more uniform across the region (Figure 2.4-

2). [Note that in these two figures, levels at Okefenokee Wilderness Area should be 

considered to be representative of levels at Wolf Island.] 
Georgia Regional Haze State Implementation Plan 

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Figure 2.4-1. Average light extinction for the 20 percent Haziest Days in 2000-2004 at VISTAS and 

neighboring Class I areas using New IMPROVE equation 

Figure 2.4-2. Average light extinction for the 20 percent Clearest Days in 2000-2004 at VISTAS and 

neighboring Class I areas using New IMPROVE equation 

VISTAS coastal VISTAS inland Neighboring non-VISTAS

0

50

100

150

200

250

300

Swanquarter, NC

Cae Romain, SC

Okefenokee, GA

Everglades, FL

Chassahowitzka, FL

St. Marks, FL

Dolly Sods, WV

Shenandoah, VA

James River Face, VA

Linville Gorge, NC

Shining Rock, NC

Great Smoky Mtns., TN

Cohutta, GA

Sipsey, AL

Mammoth Cave, KY

Brigantine, NJ

Breton, LAMingo, MO

Hercules Glade, MO

Upper Buffalo, AR

Caney Creek, AR

Extinction (Mm -1)

Sea Salt

Coarse

Soil

EC

POM

NH4NO3

(NH4)2SO4

Rayleigh

VISTAS coastal VISTAS inland Neighboring non-VISTAS

0

50

100

150

200

250

300

Swanquarter, NC

Cae Romain, SC

Okefenokee, GA

Everglades, FL

Chassahowitzka, FL

St. Marks, FL

Dolly Sods, WV

Shenandoah, VA

James River Face, VA

Linville Gorge, NC

Shining Rock, NC

Great Smoky Mtns., TN

Cohutta, GA

Sipsey, AL

Mammoth Cave, KY

Brigantine, NJ

Breton, LAMingo, MO

Hercules Glade, MO

Upper Buffalo, AR

Caney Creek, AR

Extinction (Mm -1)

Sea Salt

Coarse

Soil

EC

POM

NH4NO3

(NH4)2SO4

Rayleigh

0

10

20

30

40

50

60

Extinction (Mm-1)

Sea Salt

CM

Soil

EC

POM

NH4NO3

(NH4)2SO4

Rayleigh

VISTAS coastal VISTAS inland Neighboring non-VISTAS

Swanquarter, NC

Cae Romain, SC

Okefenokee, GA

Everglades, FL

Chassahowitzka, FL

St. Marks, FL

Dolly Sods, WV

Shenandoah, VA

James River Face, VA

Linville Gorge, NC

Shining Rock, NC

Great Smoky Mtns., TN

Cohutta, GA

Sipsey, AL

Mammoth Cave, KY

Brigantine, NJ

Breton, LAMingo, MO

Hercules Glade, MO

Upper Buffalo, AR

Caney Creek, AR

0

10

20

30

40

50

60

Extinction (Mm-1)

Sea Salt

CM

Soil

EC

POM

NH4NO3

(NH4)2SO4

Rayleigh

VISTAS coastal VISTAS inland Neighboring non-VISTAS

Swanquarter, NC

Cae Romain, SC

Okefenokee, GA

Everglades, FL

Chassahowitzka, FL

St. Marks, FL

Dolly Sods, WV

Shenandoah, VA

James River Face, VA

Linville Gorge, NC

Shining Rock, NC

Great Smoky Mtns., TN

Cohutta, GA

Sipsey, AL

Mammoth Cave, KY

Brigantine, NJ

Breton, LAMingo, MO

Hercules Glade, MO

Upper Buffalo, AR

Caney Creek, AR
Georgia Regional Haze State Implementation Plan 

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Particulate Organic Matter (POM) is the second most important contributor to fine 

particle mass and light extinction on the 20 percent haziest and the 20 percent clearest 

days at the Georgia Class I areas. Elevated levels of POM and elemental carbon (EC) 

indicate impact from wildfires or prescribed fires. Significant fire impacts are infrequent 

at Class I areas in Georgia. Wood burning is more important in the fall, winter, and 

early spring months. Biogenic emissions, chiefly emissions of volatile organics (VOC) 

from vegetation, peak in spring and summer. Biogenic carbon emissions at Cape 

Romain, South Carolina, a coastal site similar to Wolf Island, Georgia were lower than 

emissions at the forested mountain sites. Carbon from gasoline and diesel engines is a 

relatively small contribution at the rural sites. Modeling results suggest that controlling 

anthropogenic sources of carbon will have little benefit in improving visibility in Class I 

areas. Controlling anthropogenic sources of carbon will likely be more effective to 

reduce levels of PM2.5 in urban areas. 

Ammonium nitrate, NH4NO3, is formed in the atmosphere by reaction of ammonia and 

nitrogen oxides. In the VISTAS region, nitrate formation is limited by availability of 

ammonia and by temperature. Ammonia preferentially reacts with sulfur dioxide and 

sulfate before reacting with nitrogen oxides. Particle nitrate is formed at lower 

temperatures; at elevated temperatures nitric acid remains in gaseous form. For this 

reason, particle nitrate levels are very low in the summer and a minor contributor to 

visibility impairment. Particle nitrate concentrations are higher on winter days and are 

more important for the coastal sites where 20 percent worst days can occur on winter 

days. Nitrogen oxides are emitted by fossil fuel combustion by point, area, on-road, and 

non-road sources. Modeling data (see Section 7) indicate that in the VISTAS region 

ammonium nitrate formation is limited by ammonia concentrations and suggest that for 

winter days, controls of ammonia sources would be more effective in reducing 

ammonium nitrate levels than controls of nitrogen oxides. 

 

Elemental Carbon( EC) is a comparatively minor contributor to visibility impairment. 

Sources include agriculture, prescribed, wildland, and wild fires and incomplete 

combustion of fossil fuels. EC levels are higher at urban monitors than at the Class I 

areas and suggest controls of fossil fuel combustion sources would be more effective to 

reduce PM2.5 in urban areas than to improve visibility in Class I areas. 

Soil fine particles are minor contributors to visibility impairment at most sites on most 

days. Occasional episodes of elevated fine soil can be attributed to Saharan dust 

episodes, particularly at Everglades, Florida but rarely are seen at the Georgia Class I 

areas. No control strategies are indicated for fine soil. 

Sea salt (NaCl) is observed at the coastal sites. Sea salt contributes to visibility 

impairment are most important on the 20 percent clearest days when sulfate and POM 

levels are low. Sea salt levels do not contribute significantly to visibility on the 20 

percent worst visibility days. The new IMPROVE equation uses Chloride ion (Cl-

) from 

routine IMPROVE measurements to calculate sea salt levels. Cl- may react with nitrates 

and volatize off the filter, so that Cl-

 may underestimate sea salt levels. VISTAS funded 

sodium ion (Na+

) analyses of the IMPROVE filters from October 2003 to December 
Georgia Regional Haze State Implementation Plan 

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2004 for nine sites. Sodium ion measures may overestimate sea salt levels because 

sodium nitrate is an additional source of sodium ion that cannot be distinguished from 

sodium chloride. Our best understanding to date suggests that using Cl- may 

underestimate sea salt levels by as much as a factor of two. This uncertainty has 

greatest implications for calculating sea salt levels under natural visibility conditions. 

Coarse particle mass (particles with diameters between 2.5 and 10 microns) has a 

relatively small contribution to visibility impairment because the light extinction efficiency 

of coarse mass is very low compared to the extinction efficiency for sulfate, nitrate, and 

carbon. 

An unidentified component is reported by IMPROVE as the difference between the total 

PM2.5 mass measured on the filter and the sum of the measured components. This 

unidentified mass may be positive or negative and is attributable to water and/or the 

factors used to calculate molecular weights of the other components. 

 

The new IMPROVE equation, compared to the former version, generally results in 

higher calculated light extinction on days with higher mass and lower light extinction on 

days with lower mass. This tends to increase calculated light extinction for current 

conditions and to decrease calculated light extinction for natural visibility conditions. 

Adding sea salt to the new IMPROVE equation increases light extinction for both current 

and natural visibility conditions. Increasing the mass multiplier for particulate organic 

matter in the new IMPROVE equation increases light extinction for current conditions 

more than for natural conditions. The new algorithm does not change the conclusion 

that, in the VISTAS region and in Georgia, the most effective means to improve visibility 

is to reduce sulfate concentrations. 

PM2.5 trends in urban and Class I areas: IMPROVE data was compared to monitoring 

data from the Speciated Trends Network (STN) in nearby urban areas to understand the 

similarities and differences in composition of fine particle mass. Several PM2.5 nonattainment areas are in close proximity to the Class I areas in the southeastern United 

States, including Atlanta, Georgia; Birmingham, Alabama; Charleston, West Virginia; 

Chattanooga, Tennessee; Louisville, Kentucky; and Knoxville, Tennessee. Ammonium 

sulfate concentrations are comparable between urban and nearby Class I areas, while 

organic carbon, elemental carbon, and nitrate concentration are generally higher in 

urban areas than in the Class I areas. These results suggest that sulfate is widely 

distributed regionally while urban areas see additional incremental pollutant loadings 

from local emissions sources. 

Role of meteorology in determining visibility conditions: Classification and Regression 

Tree Analyses were used to characterize the relationship between meteorological 

conditions and visibility conditions at the Class I areas. Days were assigned to one of 

five visibility classes ranging from poor to good visibility. Days were then assigned to 

bins based on meteorological conditions. Weights were assigned to days based on 

frequency of occurrence of days with similar meteorological conditions. For the Georgia 

Class I areas, poor visibility days were most likely to occur on days with high 
Georgia Regional Haze State Implementation Plan 

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temperatures, high relative humidity, low wind speeds, and elevated PM2.5 mass at 

upwind urban areas. Precipitation was not a good predictor of visibility condition. 

The above analyses are further discussed in Appendix L. 
Georgia Regional Haze State Implementation Plan 

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3.0 GLIDEPATHS FOR CLASS I AREAS IN GEORGIA 

The following are glidepaths for the 20 percent most impaired days Cohutta Wilderness 

Area, assuming uniform rate of progress toward regional haze goals. Natural 

background visibility at all four sites is predicted to be between 11 and 12 dv. The 

Class I area with the steepest slope from baseline to natural background conditions is 

Cohutta Wilderness Area. Note that the rate of progress for Okefenokee is considered 

representative of Wolf Island. 

Figure 3.1-1. Uniform Rate of Progress Glidepath for 20 percent worst days at Cohutta Wilderness 

Area 

Uniform Rate of Progress Glide Path

Cohutta - Worst 20% Data Days

30.25

28.63

25.71

22.46

19.22

15.97

12.73

10.78

0

5

10

15

20

25

30

35

2000 2004 2008 2012 2016 2020 2024 2028 2032 2036 2040 2044 2048 2052 2056 2060 2064

Year

Haziness Index (Deciviews)

Glide Path Natural Condition (Worst Days) Observation

Uniform rate of progress = 4.5 dv by 2018
Georgia Regional Haze State Implementation Plan 

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Figure 3.1-2. Uniform Rate of Progress Glidepath for 20 percent worst days at Okefenokee 

Wilderness Area 

Uniform rate of progress = 3.7 dv by 2018 

Uniform Rate of Progress Glide Path

Okefenokee

27.13

25.81

23.42

20.76

18.11

15.45

12.80

11.21

0

5

10

15

20

25

30

35

2000 2004 2008 2012 2016 2020 2024 2028 2032 2036 2040 2044 2048 2052 2056 2060 2064

Year

Haziness Index (Deciviews)

Glide Path Natural Condition (Worst Days) Observation
Georgia Regional Haze State Implementation Plan 

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4.0 NATURE OF THE PROBLEM: CHIEF CAUSES OF VISIBILITY 

IMPAIRMENT IN GEORGIA CLASS I AREAS

4.1 Baseline Emissions Inventory

The Regional Haze Rule at 51.308(d)(4)(v) requires a statewide emissions inventory of 

pollutants that are reasonably anticipated to cause or contribute to visibility impairment 

in any mandatory Class I area. An inventory was developed for the baseline year 2002 

and projected to 2009 and 2018. The pollutants inventoried include volatile organic 

compounds (VOCs), nitrogen oxides (NOx), fine particulate (PM2.5), coarse particulate 

(PM10), ammonia (NH3) and sulfur dioxide (SO2). The baseline emissions inventory 

for 2002 was developed for Georgia following the methods described in Appendix C. 

There are five different emission inventory source classifications: stationary point and 

area sources, off-road and on-road mobile sources, and biogenic sources. Stationary 

point sources are those sources that emit greater than a specified tonnage per year, 

with data provided at the facility level. Electric generating utilities and industrial sources 

are the major categories for stationary point sources. Stationary area sources are those 

sources whose individual emissions are relatively small, but due to the large number of 

these sources, the collective emissions from the source category could be significant 

(i.e., dry cleaners, service stations, agricultural sources, fire emissions, etc.). These 

types of emissions are estimated on a countywide level. Non-road (or off-road) mobile 

sources are equipment that can move but do not use the roadways, i.e., lawn mowers, 

construction equipment, railroad locomotives, aircraft, etc. The emissions from these 

sources, like stationary area sources, are estimated on a countywide level. On-road 

mobile sources are automobiles, trucks, buses, and motorcycles that use the roadway 

system. The emissions from these sources are estimated by vehicle type and road type 

and are summed to the countywide level. Biogenic sources are the natural sources like 

trees, crops, grasses and natural decay of plants. The emissions from these sources 

are estimated on a countywide level. 

In addition to the various source classifications, there are also various types of emission 

inventories. The first is the actual base-year inventory. This inventory is the base-year 

emissions that correspond to the meteorological data used, which for this modeling 

effort is data from 2002. These emissions are used for evaluating the air quality model 

performance. 

The second type of inventory is the typical base year inventory. This inventory is similar 

to the actual base-year inventory, except that for sources whose emissions change 

significantly from year to year, a more typical emission value is used. In this modeling 

effort, typical emissions were developed for the electric generating units (EGUs) and the 

wildland fire emissions. The air quality modeling runs using the typical base-year 

inventory provide results, which are then used to calculate relative reduction factors for 

future years. These relative reduction factors for future years are then used to 

demonstrate reasonable progress toward visibility goals. 
Georgia Regional Haze State Implementation Plan 

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Below is an overview of the inventories used for each source classification. More 

detailed discussion of the emissions inventory development is contained in Appendix C.

4.1.1 Stationary Point Sources 

Point source emissions are emissions from individual sources having a fixed location. 

Generally, these sources must have permits to operate, and their emissions are 

inventoried on a regular schedule. Point sources emitting at least 100 tons per year 

(tpy) of VOC, PM10, PM2.5, NH3, SO2, or NOx are inventoried. The point source 

emissions data can be grouped as EGU sources and other industrial point sources, also 

called non-EGUs. 

Electric Generating Units

The actual base year inventory for the EGU sources used 2002 continuous emissions 

monitoring (CEM) data reported to the US EPA’s Acid Rain program or 2002 hourly 

emissions data provided by stakeholders. The data provides hourly emissions profiles 

for SO2 and NOx that can be used in air quality modeling. Emissions profiles are used 

to estimate emissions of other pollutants (volatile organic compounds, carbon 

monoxide, ammonia, fine particles, soil) based on measured emissions of SO2 and 

NOx. 

Emissions from EGUs vary daily and seasonally as a function of variability in energy 

demand and utilization and outage schedules. To avoid anomalies in future-year 

emissions created by relying on 2002 operations to represent future operations, a 

typical base-year emissions inventory was developed for EGUs. This approach is 

consistent with the US EPA’s modeling guidance (Appendix G). To develop a typical 

year 2002 emissions inventory for EGU sources, each unit’s average CEM heat input 

for 2000 through 2004 was divided by the 2002 actual heat input to generate a unit 

specific normalizing factor. This normalizing factor was then multiplied by the 2002 

actual emissions. The heat inputs for the period 2000 through 2004 were used because 

the modeling current design values use monitored data from this same 5-year period. If 

a unit was shut down for an entire year during the 2000 through 2004 period, the 

average of the years the unit was operational was used. If a unit was shut down in 

2002, but not permanently shutdown, the emissions and heat inputs from 2001 (or 

2000) were used in the normalizing calculations. 

As part of the VISTAS air quality modeling, VISTAS, in cooperation with the other 

eastern RPOs, contracted with ICF Resources, L.L.C., to generate future-year emission 

inventories for the electric generating sector of the contiguous United States using the 

Integrated Planning Model (IPM). IPM is a dynamic linear optimization model that can 

be used to examine air pollution control policies for various pollutants throughout the 

contiguous United States for the entire electric power system. The dynamic nature of 

IPM enables projection of the behavior of the power system over a specified future 

period. Optimization logic in IPM determines the least-cost means of meeting electric 

generation and capacity requirements while complying with specified constraints 

including air pollution regulations, transmission bottlenecks, and plant-specific 
Georgia Regional Haze State Implementation Plan 

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operational constraints. The versatility of IPM allows users to specify which constraints 

to exercise and to populate IPM with their own datasets. 

The IPM modeling runs took into consideration both CAIR implementation and 

Georgia’s Multipollutant rule requirements for Georgia Power. 

 

Other Industrial Point Sources

For the non-EGU sources, the same inventory is used for both the actual and typical 

base-year emissions inventories. The non-EGU category uses annual emissions as 

reported under the Consolidated Emissions Reporting Rule (CERR) for the year 2002. 

These emissions are temporally allocated to month, day, and hour using source 

category code (SCC)-based allocation factors. 

The general approach for assembling future-year data was to use recently updated 

growth and control data consistent with US EPA’s CAIR analyses. This data was 

supplemented with state-specific growth factors and stakeholder input on growth 

assumptions.

4.1.2 Stationary Area Sources 

Stationary area sources are sources whose individual emissions are relatively small, but 

due to the large number of these sources, the collective emissions could be significant 

(i.e., combustion of fuels for heating, structure fires, service stations, etc.). Emissions 

are estimated by multiplying an emission factor by some known indicator of collective 

activity, such as fuel usage, number of households, or population. Stationary area 

source emissions are estimated at the countywide level. 

The VISTAS contractor used data reported by Georgia under CERR for 2002 area 

source inventory. GA EPD only provided additional data from other years in order to 

generate typical fire emissions. 

The actual base-year inventory will serve as the typical base-year inventory for all area 

source categories except for wildland fires. For wildland fires, a typical year inventory 

was used to avoid anomalies in wildfire activity in 2002 compared to longer-term 

averages. Development of a typical year fire inventory provided the capability of using a 

comparable data set for both the base year and future years. Thus, fire emissions 

remain the same for air quality modeling in both the base and any future years. The 

VISTAS Fire Special Interest Work Group used State records to ratio the number of 

acres burned over a longer term period (three or more years, as available from state 

records) to 2002. Based on these ratios, the 2002 acreage was then scaled up or down 

to develop a typical year inventory. 

Future Year Emissions 

The VISTAS contractor generated future-year emissions inventories for 2009 and 2018 

for the regional haze modeling. Growth factors, supplied either by states or taken from 

the CAIR emission projections, were applied to project the controlled emissions to 2018. 

If no growth factor was available from either a state or the CAIR growth factor files, then 
Georgia Regional Haze State Implementation Plan 

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the US EPA’s Economic Growth and Analysis System Version 5 growth factors were 

used.

4.1.3 Off-Road Mobile Sources 

Off-road (or non-road) mobile sources are equipment that can move but do not use the 

roadways, such as construction equipment, aircraft, railroad locomotives, lawn and 

garden equipment, etc. For the majority of the non-road mobile sources, the emissions 

for 2002 were estimated using the US EPA’s NONROAD2005 model. For the three 

source categories not included in the NONROAD model, i.e., aircraft engines, railroad 

locomotives and commercial marine, more traditional methods of estimating the 

emissions were used. The same inventory is used for both the actual and typical baseyear emissions inventories. 

For the source categories estimated using the US EPA’s NONROAD model, the model 

growth assumptions were used to create the 2009 and 2018 future-year inventories. 

The NONROAD model takes into consideration regulations affecting emissions from 

these source categories. For the commercial marine, railroad locomotives and the 

airport emissions, the VISTAS contractor calculated the future growth in emissions 

using detailed inventory data (both before and after controls) for 1996 and 2010, 

obtained from the CAIR Technical Support Document. When available, state-specific 

growth factors were used.

4.1.4 Highway Mobile Sources 

For on-road vehicles, the newest version of the MOBILE model, MOBILE6.2, was used. 

Key inputs for MOBILE include information on the age of vehicles on the roads, the 

average speeds on the roads, the mix of vehicles on the roads, any programs in place 

in an area to reduce emissions for motor vehicles (e.g., emissions inspection programs), 

and temperature. 

The MOBILE model takes into consideration regulations that affect emissions from this 

source sector. The same MOBILE run is used to represent the actual and typical year 

emissions for on-road vehicles using input data reflective of 2002. The MOBILE model 

then is run for 2018 inventory using input data reflective of that year. Area-specific 

vehicle age distributions were modeled. Emissions were modeled using vehicle miles 

traveled estimates obtained from the Georgia Department of Transportation.

4.1.5 Biogenic Emission Sources 

Biogenic emissions were prepared with the SMOKE-BEIS3 (Biogenic Emission 

Inventory System 3 version 0.9) preprocessor. SMOKE-BEIS3 is a modified version of 

the Urban Airshed Model (UAM)-BEIS3 model. Modifications include use of MM5 data, 

gridded land use data, and improved emissions characterization. The emission factors 

that are used in SMOKE-BEIS3 are the same as the emission factors as in UAM-BEIS3. 

The basis for the gridded land use data used by BEIS3 is the county land use data in 

the Biogenic Emissions Landcover Database version 3 (BELD3) provided by the US 

EPA. A separate land classification scheme, based upon satellite (AVHRR, 1 km 
Georgia Regional Haze State Implementation Plan 

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spatial resolution) and census information, aided in defining the forest, agriculture and 

urban portions of each county. 

4.1.6 Model Performance Improvements through Emissions Inventory 

Improvements 

Since the initial model performance evaluation, VISTAS has made several 

improvements to the emissions inventory, which, in turn, improve model performance. 

These inventory improvements are detailed in the VISTAS emissions inventory report 

and Appendix C, and are summarized here: 

• For electric generating utilities, the Integrated Planning Model (IPM) was used to 

provide estimates of future-year utility production and emissions. Continuous 

Emissions Monitoring data was used to define seasonal variability in production 

and emissions. For Base G4 emissions, states updated IPM model projections 

from 2005 with control data provided by utility companies in 2006 through winter 

2007. 

• For on-road vehicle emissions, states and local agencies provided updated 

MOBILE model input and vehicle-miles-traveled data. 

• For ammonia emissions from agricultural sources, the Carnegie Mellon 

University ammonia model was used to improve annual and monthly estimates. 

• For fires, the VISTAS states provided fire activity data for 2002 for wildfires, 

prescribed fire, land clearing and agricultural burning and MACTEC developed a 

2002 fire inventory. Where data allowed, Alpine Geophysics modeled fire events 

as point sources. In 2006, the United States Forest Service and the Fish and 

Wildlife Service provided projections of increased prescribed burning in 2009 and 

2018. The data was incorporated in the Base G inventory for all states except 

Florida. 

• For non-road engines, the updated US EPA NONROAD2005 emissions model 

was used in Base G. 

For commercial marine emissions in shipping lanes in the Gulf of Mexico and Atlantic 

Oceans, ENVIRON created gridded emissions for the VISTAS modeling domain using 

inventory data newly developed for US EPA by Corbett at University of Delaware. 

These emissions were incorporated in the Base G modeling. 

Updated inventories from the neighboring RPOs, Mexico, and Canada were 

incorporated as available. 

4.1.7 Summary 2002 Base G2 Baseline Emissions Inventory for Georgia 

Table 4.1 is a summary of the 2002 baseline emission inventory for Georgia. The 

complete inventory and discussion of the methodology is contained in Appendix C. The 

emissions summaries for other VISTAS states can also be found in Appendix C. 
Georgia Regional Haze State Implementation Plan 

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Table 4.1. 2002 Emissions Inventory Summary for GA in tons per year. 

VOC NOx PM2.5 PM10 NH3 SO2 

Point 34,964.3 197,376.9 22,531.7 33,077.3 3,699.2 571,410.9

Area 333,044.8 49,987.4 159,437.8 757,656.1 83,066.0 60,370.2

On-Road 

Mobile 

283,420.6 307,731.7 5,167.8 7,245.9 10,546.2 12,183.5

NonRoad 

Mobile 

85,965.4 97,961.4 8,226.4 8,617.9 60.4 9,005.4

Biogenics 1,972,795.40 20,942.38 0 0 0 0 

TOTAL 2,710,190.50 673,999.78 195,363.50 806,597.20 97,371.80 652,970 

4.2 Assessment of Relative Contributions from Specific Pollutants and Sources 

Categories 

Ammonium sulfate is the largest contributor to visibility impairment at the Georgia Class 

I areas, and reduction of SO2 emissions would be the most effective means of reducing 

ammonium sulfate. As illustrated in Figure 4.2-1, 96 percent of SO2 emissions in the 

VISTAS states are attributable to electric generating facilities and industrial point 

sources. As shown in Table 4.1, approximately 90 percent of SO2 emissions in Georgia 

are attributable to electric generating facilities and industrial point sources. 

Figure 4.2-1. SO2 emissions in 2002 in the VISTAS States.

Vistas States SO2 Emissions (Tons) - 2002

EGU

Other Fuel Combustion

Industrial

Onroad

Nonroad

Miscellaneous

utilities: 75%

4.8 million Tons
Georgia Regional Haze State Implementation Plan 

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5.0 REGIONAL HAZE MODELING METHODS AND INPUTS 

Modeling for regional haze was performed by VISTAS for the ten southeastern states, 

including Georgia. The sections below outline the methods and inputs used by VISTAS 

for the regional modeling. Additional details are provided in Appendices C, D, and E. 

5.1 Analysis Method

The modeling analysis is a complex technical evaluation that begins by selection of the 

modeling system. VISTAS decided to use the following modeling system: 

• Meteorological Model: The Pennsylvania State University/National Center for 

Atmospheric Research (PSU/NCAR) Mesoscale Meteorological Model (MM5) is 

a nonhydrostatic, prognostic meteorological model routinely used for urban- and 

regional-scale photochemical, fine particulate matter, and regional haze 

regulatory modeling studies. 

• Emissions Model: The Sparse Matrix Operator Kernel Emissions (SMOKE) 

modeling system is an emissions modeling system that generates hourly, 

gridded, speciated emission inputs of mobile, non-road mobile, area, point, fire 

and biogenic emission sources for photochemical grid models. 

• Air Quality Model: US EPA’s Models-3/ Community Multiscale Air Quality 

(CMAQ) modeling system is a ‘One-Atmosphere’ photochemical grid model 

capable of addressing ozone, particulate matter (PM), visibility and acid 

deposition at regional scale for periods up to one year.

The US EPA Modeling Guidance (Appendix G) recommends modeling an entire year or 

at a minimum several days in each quarter of a year to adequately represent the range 

of meteorological conditions that contribute to elevated levels of fine particulate matter. 

The year 2002 was selected by VISTAS as the modeling year for this demonstration. 

Meteorological inputs were developed for 2002 using the meteorological model. 

Emission inventories were also developed for 2002 and processed through the 

emissions model. These inputs were used in the air quality model to predict fine particle 

mass and visibility. The model results for 2002 were compared with observed 

meteorological and air quality data to evaluate model performance. Several 

configurations of the meteorological and air quality model were evaluated to select a 

configuration that gave the best overall performance for the VISTAS region. 

Once model performance was deemed adequate, the current- and future-year 

emissions were processed through the emissions model. The air quality modeling 

results are used to determine a relative reduction in future visibility impairment, which is 

used to determine reasonable progress. 

The complete modeling protocol used for this analysis can be found in Appendix D.
Georgia Regional Haze State Implementation Plan 

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5.2 Model Selection 

To ensure that a modeling study is defensible, care must be taken in the selection of the 

models to be used. The models selected must be scientifically appropriate for the 

intended application and be freely accessible to all stakeholders. Scientifically 

appropriate means that the models address important physical and chemical 

phenomena in sufficient detail, using peer-reviewed methods. Freely accessible means 

that model formulations and coding are freely available for review and that the models 

are available to stakeholders, and their consultants, for execution and verification at no 

or low cost. 

The following sections outline the criteria for selecting a modeling system that is both 

defensible and capable of meeting the study's goals. These criteria were used in 

selecting the modeling system used for this modeling demonstration. 

5.2.1 Selection of Photochemical Grid Model 

Criteria

For a photochemical grid model to qualify as a candidate for use in a regional haze SIP, 

a state needs to show that it meets the same several general criteria as a model for an 

attainment demonstration for a national ambient air quality standard (NAAQS): 

• The model has received a scientific peer review. 

• The model can be demonstrated applicable to the problem on a theoretical basis. 

• Databases needed to perform the analysis are available and adequate. 

• Available past appropriate performance evaluations have shown the model is not 

biased toward underestimates or overestimates. 

• A protocol on methods and procedures to be followed has been established. 

• The developer of the model must be willing to make the source code available to 

users for free or for a reasonable cost, and the model cannot otherwise be 

proprietary. 

Overview of CMAQ

The photochemical model selected for this study was CMAQ Version 4.5. For more 

than a decade, the US EPA has been developing the Models-3 CMAQ modeling system 

with the overarching aim of producing a ”One-Atmosphere” air quality modeling system 

capable of addressing ozone, fine particulate matter, visibility and acid deposition within 

a common platform. The original justification for the Models-3 development emerged 

from the challenges posed by the 1990 Clean Air Act Amendments and the USEPA’s 

desire to develop an advanced modeling framework for “holistic” environmental 

modeling utilizing state-of-science representations of atmospheric processes in a high 

performance computing environment. The US EPA completed the initial stage of 

development with Models-3 and released the CMAQ model in mid-1999 as the initial 
Georgia Regional Haze State Implementation Plan 

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operating science model under the Models-3 framework. The most recent rendition is 

CMAQ Version 4.5, which was released in September of 2005. 

An advantage of choosing CMAQ as the atmospheric model is the ability to do oneatmospheric modeling. The same model configuration is being applied for the ozone 

and PM2.5 attainment demonstration SIPs, as well as the regional haze SIP. A number 

of features in CMAQ’s theoretical formulation and technical implementation make the 

model well-suited for annual PM modeling. 

The configuration used for this modeling demonstration, as well as a more detailed 

description of the CMAQ model, can be found in the Modeling Protocol (Appendix D).

5.2.2 Selection of Meteorological Model 

Criteria

Meteorological models, either through objective, diagnostic, or prognostic analysis, 

extend available information about the state of the atmosphere to the grid upon which 

photochemical grid modeling is to be carried out. The criteria for selecting a 

meteorological model are based on both the model’s ability to accurately replicate 

important meteorological phenomena in the region of study and the model's ability to 

interface with the rest of the modeling systems -- particularly the photochemical grid 

model. With these issues in mind, the following criteria were established for the 

meteorological model to be used in this study: 

• Non-Hydrostatic Formulation 

• Reasonably current, peer-reviewed formulation 

• Simulation of Cloud Physics 

• Public availability at no or low cost 

• Output available in I/O API format 

• Support of Four Dimensional Data Assimilation (FDDA)

• Enhanced treatment of Planetary Boundary Layer heights for AQ modeling

Overview of MM5

The non-hydrostatic MM5 model is a three-dimensional, limited-area, primitive equation, 

prognostic model that has been used widely in regional air quality model applications. 

The basic model has been under continuous development, improvement, testing and 

open peer-review for more than 20 years and has been used worldwide by hundreds of 

scientists for a variety of mesoscale studies. 

MM5 uses a terrain-following non-dimensionalized pressure, or "sigma," vertical 

coordinate similar to that used in many operational and research models. In the nonhydrostatic MM5, the sigma levels are defined according to the initial hydrostatically-
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balanced reference state so that the sigma levels are also time-invariant. The gridded 

meteorological fields produced by MM5 are directly compatible with the input 

requirements of ”one atmosphere” air-quality models using this coordinate. MM5 fields 

can be easily used in other regional air quality models with different coordinate systems 

by performing a vertical interpolation followed by a mass-conservation re-adjustment. 

Distinct planetary boundary layer (PBL) parameterizations are available for air-quality 

applications, both of which represent sub-grid-scale turbulent fluxes of heat, moisture 

and momentum. One scheme uses a first-order eddy diffusivity formulation for stable 

and neutral environments and a modified first-order scheme for unstable regimes. The 

other scheme uses a prognostic equation for the second-order turbulent kinetic energy, 

while diagnosing the other key boundary layer terms. 

Initial and lateral boundary conditions are specified for real-data cases from mesoscale 

3-dimensional analyses performed at 12-hour intervals on the outermost grid mesh 

selected by the user. Surface fields are analyzed at 3-hour intervals. A Cressmanbased technique is used to analyze standard surface and radiosonde observations, 

using the National Meteorological Center's spectral analysis, as a first guess. The lateral 

boundary data is introduced using a relaxation technique applied in the outermost five 

rows and columns of the coarsest grid domain. 

MM5 modeling systems, in regulatory air quality application studies, have been widely 

reported in the literature (e.g., Emery et al., 1999; Tesche et al., 2000, 2003) and many 

have involved comparisons with other prognostic models such as the Regional 

Atmospheric Modeling System (RAMS) and the Systems Application International 

Mesoscale Model. The MM5 enjoys a far richer application history in regulatory 

modeling studies compared with RAMS or other models. Furthermore, in evaluations of 

these models in over 60 recent, regional-scale air quality application studies since 1995, 

it has generally been found that the MM5 model tends to produce somewhat better 

photochemical model inputs than alternative models. 

The configuration used for this modeling demonstration, as well as a more detailed 

description of the MM5 model, can be found in Appendix F.

5.2.3 Selection of Emissions Processing System 

Criteria

The principal criterion for an emissions processing system is that it accurately prepares 

emissions files in a format suitable for the photochemical grid model being used. The 

following list includes clarification of this criterion and additional desirable criteria for 

effective use of the system. 

• File System Compatibility with the I/O API 

• File Portability 

• Ability to grid emissions on a Lambert Conformal projection 
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• Report Capability 

• Graphical Analysis Capability 

• MOBILE6 Mobile Source Emissions 

• Biogenic Emissions Inventory System Version 3 (BEIS-3) 

• Ability to process emissions for the proposed domain in a reasonable amount of 

time 

• Ability to process control strategies 

• No or low cost for acquisition and maintenance 

• Expandability to support other species and mechanisms 

Overview of SMOKE

The SMOKE Emissions Processing System Prototype was originally developed at the 

Micro-computing Center of North Carolina. As with most ”emissions models,” SMOKE 

is principally an emission processing system and not a true emissions modeling system

in which emission estimates are simulated from ”first principles.” This means that, with 

the exception of mobile and biogenic sources, its purpose is to provide an efficient, 

modern tool for converting emissions inventory data into the formatted emission files 

required by an air quality simulation model. For mobile sources, SMOKE actually 

simulates emissions rates based on input mobile-source activity data, emission factors 

and outputs from transportation travel-demand models. 

SMOKE was originally designed to allow emissions data processing methods to utilize 

emergent high-performance-computing as applied to sparse-matrix algorithms. Indeed, 

SMOKE is the fastest emissions processing tool currently available to the air quality 

modeling community. The sparse matrix approach utilized throughout SMOKE permits 

both rapid and flexible processing of emissions data. The processing is rapid because 

SMOKE utilizes a series of matrix calculations instead of less efficient algorithms used 

in previous systems. The processing is flexible because the processing steps of 

temporal projection, controls, chemical speciation, temporal allocation, and spatial 

allocation have been separated into independent operations wherever possible. The 

results from these steps are merged together at a final stage of processing. 

 

SMOKE contains a number of major features that make it an attractive component of 

the modeling system. The model supports a variety of input formats from other 

emissions processing systems and models. It supports both gridded and county total 

land use schemes for biogenic emissions modeling. SMOKE can accommodate 

emissions files from up to 10 countries and any pollutant can be processed by the 

system. For additional information about the SMOKE model, please refer to Modeling 

Protocol (Appendix D). 
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5.3 Selection of the Modeling Year 

A crucial step to SIP modeling is the selection of the period of time to model to 

represent current air quality conditions and to project changes in air quality in response 

to changes in emissions. The year 2002 was selected as the base year for several 

reasons. 

The US EPA’s April 2007 Guidance on the Use of Models and Other Analyses for 

Demonstrating Attainment of Air Quality Goals for Ozone, PM2.5, and Regional Haze

identifies specific goals to consider when selecting one or more episodes for use in 

demonstrating reasonable progress in attaining the regional haze air quality goals. The 

US EPA recommends that episode selection derive from three principal criteria: 

• Simulate a variety of meteorological conditions; 

• Model time periods in which observed concentrations are close to the appropriate 

baseline design value or visibility impairment; 

• Model periods for which extensive air quality/meteorological data bases exist; and 

• Model a sufficient number of days so that the modeled attainment test applied at 

each monitor violating the NAAQS is based on multiple days. 

For regional haze modeling, the guidance goes further by suggesting that the preferred 

approach is to model a full, representative year. Moreover, the required RRF values 

should be based on model results averaged over the 20% worst and 20% best visibility 

days determined for each Class I area based on monitoring data from the 2000 – 2004 

baseline period. 

The US EPA also lists several other considerations to bear in mind when choosing 

potential regional haze episodes including: (a) choosing periods which have already 

been modeled, (b) choosing periods which are drawn from the years upon which the 

current design values are based, (c) including weekend days among those chosen, and 

(d) choosing modeling periods that meet as many episode selection criteria as possible 

in the maximum number of non-attainment or Class I areas as possible. Finally, the US 

EPA explicitly recommended in its 2007 guidance to use 2002 as the baseline inventory 

year. 

VISTAS adopted a logical, stepwise approach in implementing the US EPA guidance in 

order to identify the most preferable, representative year for regional haze modeling. 

These steps include the following: 

• Representativeness of Meteorological Conditions: The VISTAS meteorological 

contractor (BAMS) identified important meteorological characteristics and data 

sets in the VISTAS region directly relevant to the evaluation of candidate annual 

modeling episodes. 
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• Initial Episode Typing: At the time of selection in 2003, meteorological and air 

quality data were available for 2002 for model inputs and model performance 

evaluation. VISTAS used Classification and Regression Tree Analyses to 

evaluate visibility conditions for 2000, 2001, and 2002, the candidate modeling 

years. The year 2002 was found to be representative of conditions in the other 

two years. Subsequently, these analyses were repeated with the meteorological 

and air quality monitoring data for 2000 to 2004 to evaluate how well the 2002-

modeling year represented the full 2000-2004 baseline period. This analysis 

confirmed that visibility and PM2.5 mass in 2002 were representative of the 5-

year baseline period for the VISTAS Class I areas. This analysis is discussed in 

more detail in the project report in Appendix L. 

• Data Availability: In parallel with the CART analysis, episode characterization 

analyses, collaborative investigations by VISTAS states (e.g., NCDAQ, GAEPD, 

FL DEP) intensively studied the availability of PM2.5, meteorological, and 

emissions data and representativeness of alternative baseline modeling periods 

from a regulatory standpoint. Additionally, 2002 was the year that US EPA was 

requiring states to provide emissions inventory data for the Comprehensive 

Emissions Reporting Rule; therefore, it made sense to use 2002 as the modeling 

year to take advantage of the 2002 inventory. 

• Years to be used by other RPOs: VISTAS also considered what years other 

RPO would be modeling, and several had already chosen calendar year 2002 as 

the modeling year. 

After a lengthy process of integrated studies, the episode selection process culminated 

in the selection of calendar year 2002 (1 January through 31 December) as the most 

current, representative, and pragmatic choice for VISTAS regional haze modeling. All 

of the US EPA criteria for regional haze episode selection were directly considered in 

this process together with many other considerations (e.g., timing of new emissions or 

aerometric data deliveries by the US EPA or the states to the modeling teams). 

5.4 Modeling Domains 

5.4.1 Horizontal Modeling Domain 

The US EPA’s modeling guidance (Appendix G) recommends a 12-km modeling grid 

resolution for PM2.5 modeling while a 36-km grid is considered acceptable for regional 

haze. For the VISTAS modeling, a coarse 36-km grid resolution was used for modeling 

the entire United States and a finer 12-km grid was used to model the eastern United 

States. 

The CMAQ model was run in one-way nested grid mode. This allowed the larger outer 

domains to feed concentration data to the inner nested domain. The horizontal coarse 

grid modeling domain boundaries were determined through a national effort to develop 

a common grid projection and boundary. A smaller 12-km grid, modeling domain was 

selected in an attempt to balance location of areas of interest, such as ozone and fine 
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particulate matter non-attainment areas, as well as Class 1 and wilderness areas for 

regional haze. Processing time was also a factor in choosing a smaller 12-km grid, 

modeling domain. 

The coarse 36-km horizontal grid domain covers the continental United States. This 

domain was used as the outer grid domain for MM5 modeling with the CMAQ domain 

nested within the MM5 domain. Figure 5.4.1-1 shows the MM5 horizontal domain as 

the outer most, blue grid with the CMAQ 36-km domain nested in the MM5 domain. 

Figure 5.4.1-1. The MM5 horizontal domain is the outer most, blue grid, with the CMAQ 36-km 

domain nested in the MM5 domain. 

To achieve finer spatial resolution in the VISTAS states, a 1-way nested high resolution 

(12-km grid resolution) was used. Figure 5.4.1-2 shows the 12-km grid, modeling 

domain for the VISTAS region. This is the modeling domain for which the reasonable 

progress goals will be assessed. 
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Figure 5.4.1-2. A more detailed view of the 12-km grid over the VISTAS region.

5.4.2 Vertical Modeling Domain 

The CMAQ vertical structure is primarily defined by the vertical grid used in the MM5 

modeling. The MM5 model employed a terrain-following coordinate system defined by 

pressure, using 34 layers that extend from the surface to the 100 mb. A layer-averaging 

scheme was used to generate 19 vertical layers for CMAQ to reduce the computational 

cost of the CMAQ simulations. The effects of layer averaging were evaluated in 

conjunction with the VISTAS modeling effort and was found to have a relatively minor 

effect on the model performance metrics when both the 34-layer and a 19-layer CMAQ 

models were compared to ambient monitoring data. 
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6.0 MODEL PERFORMANCE EVALUATION 

The initial modeling effort focused on evaluating previous regional air quality modeling 

applications and testing candidate model configurations for the SMOKE emissions and 

CMAQ model for the VISTAS 36-km and 12-km modeling domains. This effort resulted 

in a report recommending the model configuration for the annual emissions and air 

quality modeling, which is included as part of the VISTAS Emissions and Air Quality 

Modeling Protocol. The evaluation of the meteorological modeling configuration can be 

found in Appendix F, with a summary of the final meteorological and air quality modeling 

configuration in Appendix F and Appendix E, respectively. 

Air quality model performance for the 2002 modeling year was initially tested in 2004 

using an early version of the VISTAS emissions inventory. In keeping with the oneatmosphere objective of the CMAQ modeling platform, model performance was 

evaluated based on measured ozone, fine particles, and acid deposition in the Air 

Quality System (AQS), IMPROVE, Speciated Trends Network (STN), Southeastern 

Aerosol Research and Characterization (SEARCH), National Acid Deposition Program 

(NADP) and Clean Air Status and Trends Network (CASTNet) monitoring networks 

(Figure 6.0-1). 

Figure 6.0-1: Monitoring Networks used for VISTAS 2002 model performance evaluation, and their 

location within the VISTAS 12km domain. 
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6.1 Modeling Performance Goals, and Criteria 

In 2004, VISTAS established model performance goals and criteria for components of 

fine particle mass (Table 6.1-1) based on previous model performance for ozone and 

fine particles. The US EPA modeling guidance (Appendix G) for fine particulate matter 

at the time noted that PM models might not be able to achieve the same level of 

performance as ozone models. VISTAS’ evaluation considered several statistical 

performance measures and displays. Fractional bias and mean fractional error were 

selected as the most appropriate metrics to summarize model performance; other 

metrics were also calculated and are included for IMPROVE monitors in the full model 

performance evaluation (Appendix E). 

Table 6.1-1.: Established model performance goals and criteria for the component 

species of fine particle mass. 

Fractional 

Bias 

Mean 

Fractional 

Error 

Comment 

<15 percent <35 percent Goal for PM model performance based on ozone 

model performance, considered excellent 

performance 

<30 percent <50 percent Goal for PM model performance, considered 

good performance 

<60 percent <75 percent Criteria for PM model performance, considered 

average performance. Exceeding this level of 

performance indicates fundamental concerns 

with the modeling system and triggers diagnostic 

evaluation. 

Several graphic displays of model performance were prepared including: 

1. Scatter plots of predicted and observed concentrations and deposition by 

species, monitoring network, and month; 

2. Time series plots of predicted and observed concentrations and deposition by 

species, monitoring site, and month; 

3. Spatially average time series plots; 

4. Time series plots of monthly fractional bias and error for a species, region, and 

network; 

5. Performance goal plots (“soccer plots”) that summarize model performance by 

species, region, season; and 

6. Concentration performance plots (“bugle plots”) that display fractional bias or 

error as a function of concentration by species, region, monitoring network, and 

month.

The “soccer plots” and “bugle plots” are relatively new tools in model performance 

evaluations, and have recently been included as model performance evaluation displays 
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in US EPA’s modeling guidance for Ozone, PM2.5, and Regional Haze (Appendix G). 

Both “soccer plots” and “bugle plots” allow for convenient ways to examine model 

performance with respect to set goals and criteria. The bugle plots have the added 

benefit of adjusting the goals and criteria to consider the concentration of the species. 

Analysis of “bugle plots” generally suggests that greater emphasis should be placed on 

performance of those components with the greatest contribution to PM mass and 

visibility impairment (e.g. sulfate and organic carbon) and that greater bias and error 

could be accepted for components with smaller contributions to total PM mass (e.g. 

elemental carbon, nitrates, and soil). 

6.2 VISTAS Domain - Wide Performance 

Further discussion of model performance in this document will focus on the comparison 

of observational data from the IMPROVE monitors and model output data from the 2002 

VISTAS BaseG4-Actual annual air quality modeling. Focus is limited to the IMPROVE 

monitoring network as these sites are the locations used in projecting attainment 

visibility improvement goals in the Class I areas. 

The evaluation will primarily focus on the air quality model’s performance with respect to 

individual components of fine particulate matter (PM2.5), as good model performance of 

the component species will dictate good model performance of total or reconstituted fine 

particulate matter. Model performance of the total fine particulate matter and the 

resulting total light extinction will also be provided as a means to discuss the overall 

model performance for this Implementation Plan. 

In our analyses, mean fractional bias (error) is used in lieu of mean bias (error), to 

prevent low observations and model predictions from skewing the metrics. A full list of 

model performance statistics is found in Appendix E. The soccer and bugle plots for all 

of the VISTAS IMPROVE monitors are included here for summary purposes. Plots 

have been developed for the average monthly concentrations and the performance 

statistics for all of the most significant light-scattering component species (sulfate, 

nitrate, and organic carbon) for the 20% best days and 20% worst days. Plots for 

individual IMPROVE monitors associated with Georgia Class I areas are included in 

Appendix E. 

The soccer plots of monthly concentrations (Figures. 6.2-1 and 6.2-2) show that values 

for nitrate generally fall outside of criteria performance thresholds. Sulfates and organic 

carbon generally fall within goal thresholds with a couple of months falling just outside 

the goal thresholds but well within the criteria thresholds. Figure 6.2-3 contains 

separate soccer plots for each season. The seasonal plots emphasize poorer nitrate 

performance in the summer (does not even appear on the plots provided because 

performance is off scale with other constituents) when observed nitrate is quite low and 

predicted nitrate is even lower. When concentration is factored into performance 

criteria, nitrate performance improves with respect to MFB and MFE (Figures 6.2-4 and 

6.2-5). 
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Additionally, performance assessed at the “one atmosphere” level was also deemed 

acceptable for ozone and particulate matter at various monitoring sites (STN, FRM, 

CASTNet, etc.). Overall, VISTAS found the Base G2 modeling results to be 

representative and acceptable for use in modeling projection for ozone, particulate 

matter, and regional haze. 

Figure 6.2-1.: Soccer plot depicting both the mean fractional error and fractional bias for 

component concentration for all VISTAS sites based on Base G2 results. Each point represents a 

monthly value as compared to the model performance criteria (red box) and modeling 

performance goals (green box). 

Figure 6.2-2.: A zoomed view of the soccer plot depicting both the mean fractional error and 

fractional bias for component concentration for all VISTAS sites based on Base G2 results. Each 

point represents a monthly value as compared to the model performance criteria (red box) and 

modeling performance goals (green box). 

All Sites CMAQ 12km - 2002 Monthly

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

180.0

200.0

-180.0 -120.0 -60.0 0.0 60.0 120.0 180.0

Fractional Bias

Mean Fractional Error 

Sulfate

Nitrate

Organics

Criteria

Goal

All Sites CMAQ 12km - 2002 Monthly

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

-75.0 -25.0 25.0 75.0

Fractional Bias

Mean Fractional Error 

Sulfate

Nitrate

Organics

Criteria

Goal
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Figure 6.2-3.: Seasonal soccer plots based on Base G1 results for all VISTAS IMPROVE monitors. 
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Figure 6.2-4.: Bugle plot of the mean fraction error for particulate matter and its component 

concentrations for all VISTAS sites based on Base G2 results. Each point represents a monthly 

mean fraction error value as compared to the model performance criteria (red lines) and modeling 

performance goals (green lines). 

All Sites CMAQ 12km - 2002 Monthly

-200.0

-150.0

-100.0

-50.0

0.0

50.0

100.0

150.0

200.0

0.0 1.0 2.0 3.0 4.0 5.0 6.0

Average Concentration (μg/m3)

Mean Fractional Bias 

Sulfate

Nitrate

Organics

(+) Criteria

(+) Goal

(-) Goal

(-) Criteria

Figure 6.2-5.: Bugle plot of mean fraction bias for particulate matter and its component species for 

all VISTAS sites based on Base G2 results. Each point represents a monthly mean fraction bias 

value as compared to the model performance criteria (red lines) and modeling performance goals 

(green lines). 

All Sites CMAQ 12km - 2002 Monthly

0.0

50.0

100.0

150.0

200.0

0.0 1.0 2.0 3.0 4.0 5.0 6.0

Average Concentration (μg/m3)

Mean Fractional Error 

Sulfate

Nitrate

Organics

Criteria

Goal
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6.3 Georgia Class I Areas Performance 

The following section provides bar charts comparing observed fine particulate matter 

composition and modeled fine particulate matter composition. The charts have been 

split into two charts, with the first displaying the 20% best days followed by the chart for 

the 20% worst days. Stacked bar charts have been developed for each of the 

IMPROVE monitoring sites relevant to Georgia: Cohutta Wilderness Area and 

Okefenokee Wilderness Area (See Figure 1.4-1). The Okefenokee Wilderness Area’s 

IMPROVE monitor is used to represent Wolf Island. 

The stacked bar chart allows a side-by-side comparison of the each day observed and 

modeled compositional and total light extinction. Within each bar the color codes are: 

• Yellow = light extinction due to sulfates (bextSO4) 

• Red = light extinction due to nitrates (bextNO3) 

• Green = light extinction due to organic carbon (bextOC) 

• Black = light extinction due to elemental (bextEC) 

• Brown = light extinction due to soil (bextSoil) 

• Grey = light extinction due to coarse mass (bextCM)

The components are presented in the same order for both the observed (left hand bar) 

and modeled bar (right hand bar), so it is easy to identify days when the prediction light 

extinction for the component differs from the observed. The total height of the bar 

provides the total reconstructed particulate matter light extinction value. 

A cursory view of the stacked bar charts reiterates that sulfates are a large contributor 

to light extinction in the Georgia Class I areas on both 20% best days and 20% worst 

days. The bar charts also suggest that organic carbon and nitrates are important on the 

20% best days at the two IMPROVE sites of interest for Georgia. The bar charts for the 

20% best reiterate the general over prediction. The over prediction of sulfate on most of 

the 20% best days appears to be the crux of the over prediction, with the over prediction 

of nitrate factoring in heavily on some days. 

Comparing the 20% best day charts to the 20% worst days charts, the various 

components of particle pollution play a more prominent role in the 20% best days than 

with the 20% worst days. Also, the species makeup on the 20% best days varies more 

widely compared to the 20% worst days. This suggests accurately modeling each 

species is especially important on the 20% best days. 

With the bar chart for the 20% worst days, you can see the general under prediction. 

The under prediction of sulfate on some of the 20% worst days appears to be the cause 

of the overall under prediction with the under prediction of organic carbon factoring in 

heavily on few days. 
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Overall, the GA EPD found model performance to fall within acceptable limits for model 

performance. The GA EPD further asserts the “one atmosphere” modeling performed 

by the VISTAS contractors is representative of conditions in the southeastern states and 

is applicable for use in attainment demonstrations. 
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6.3.1 Cohutta Wilderness Area 

Best 20% Obs (left) vs 2002gt2a (right) at COHU1

0

10

20

30

40

50

60

70

80

23 26 32 38 44 62 77 89 113 116 119 173 194 257 269 308 320 341 347 356 _ _ _ _ _ Avg

Julian Day in Best 20% group

bEXT (1/Mm)

bCM

bSOIL

bEC

bOC

bNO3

bSO4

Worst 20% Obs (left) vs 2002gt2a (right) at COHU1

0

100

200

300

400

500

600

56 122 152 155 185 188 191 197 206 215 218 221 224 227 233 248 251 260 263 266 281 _ _ _ _ Avg

Julian Day in Worst 20% group

bEXT (1/Mm)

bCM

bSOIL

bEC

bOC

bNO3

bSO4

Figure 6.3-1.: Stacked bar chart for COHU on the 20% best days (top) and 20% worst days 

(bottom). Observed composition is presented in the left hand bar, with modeled composition 

represented by the right hand bar.
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6.3.2 Okefenokee Wilderness Area

Best 20% Obs (left) vs 2002gt2a (right) at OKEF1

0

10

20

30

40

50

60

11 20 38 59 62 104 170 173 176 179 191 239 242 257 266 275 284 335 344 347 356 359 _ _ _ Avg

Julian Day in Best 20% group

bEXT (1/Mm)

bCM

bSOIL

bEC

bOC

bNO3

bSO4

Worst 20% Obs (left) vs 2002gt2a (right) at OKEF1

0

50

100

150

200

250

300

350

17 23 44 56 89 95 122 128 155 188 197 200 218 236 254 260 263 281 296 308 338 341 350 _ _ Avg

Julian Day in Worst 20% group

bEXT (1/Mm)

bCM

bSOIL

bEC

bOC

bNO3

bSO4

Figure 6.3-2.: Stacked bar chart for OKEF on the 20% best days (top) and 20% worst days 

(bottom). Observed composition is presented in the left hand bar, with modeled composition 

represented by the right hand bar. 
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7.0 LONG-TERM STRATEGY FOR GEORGIA CLASS I AREAS 

As stated in Section 1.3 above, the regional haze rule requires States to establish 

reasonable progress goals, expressed in deciviews, for visibility improvement at each 

affected Class I area covering each (approximately) 10-year period until 2064. This first 

set of reasonable progress goals must be met through measures contained in the 

state’s long-term strategy covering the period from the baseline until 2018. This section 

discusses development of Georgia’s long-term strategy. 

7.1 Overview of the Long-Term Strategy Development Process 

The monitored data and modeling analyses cited in Sections 2 and 5 above establish 

that for the VISTAS region, the key contributors to regional haze in the 2000-2004 

baseline timeframe were large stationary sources of sulfur dioxide emissions. Keeping 

that key conclusion in mind, this section addresses the following questions: 

Assuming implementation of existing federal and state air regulatory 

requirements in Georgia and the VISTAS region, how much visibility 

improvement, compared to the glidepath, would we expect to see at Class I 

areas in Georgia between now and 2018? 

If additional emission reductions are to be considered, from what pollutants and 

source categories would the greatest visibility benefits be realized between the 

baseline and 2018? 

Narrowing down further, in what geographic locations do we find the emissions 

which have the greatest impact on visibility in specific Class I areas? 

What types of emissions sources do we find in those geographic locations? 

Which specific individual sources in those geographic locations have the greatest 

visibility impacts at a given Class I area? 

What additional emission controls represent reasonable progress for those 

specific sources? 

What additional emission controls represent BART in Georgia? 

Given the additional emission reductions expected from reasonable progress and 

BART, how much additional visibility improvement, compared to the glidepath, 

will we expect to see at Class I areas in Georgia between the baseline and 

2018?
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7.2 Expected Visibility Results in 2018 for Georgia Class I Areas under existing 

and planned emissions controls (Base G4 Inventory) 

There are significant control programs being implemented between the baseline period 

and 2018. These programs are described in more detail below. 

7.2.1 Federal and State Control Requirements 

• Clean Air Interstate Rule (CAIR). Utility projections are based on Integrated Planning Model. 

US EPA issued CAIR, which will permanently cap emissions of sulfur dioxide (SO2) and 

nitrogen oxides (NOx) in the eastern United States. CAIR achieves large reductions of SO2 

and/or NOx emissions across 28 eastern states and the District of Columbia. When fully 

implemented, CAIR will reduce SO2 emissions in these states by over 70 percent and NOx 

emissions by over 60 percent from 2003 levels. These reductions were taken into account 

in the 2018 base G4 inventory

• Heavy Duty Diesel (2007) Engine Standard. A PM emissions standard for new heavy-duty 

engines of 0.01 grams per brake-horsepower-hour (g/bhp-hr), to take full effect for diesels in 

the 2007 model year. Also includes standards for NOx and non-methane hydrocarbons 

(NMHC) of 0.20 g/bhp-hr and 0.14 g/ bhp-hr, respectively. These NOx and NMHC 

standards will be phased in together between 2007 and 2010 for diesel engines. Sulfur in 

diesel fuel must be lowered to enable modern pollution-control technology to be effective on 

these trucks and buses. EPA will require a 97 percent reduction in the sulfur content of 

highway diesel fuel from its current level of 500 parts per million (low sulfur diesel, or LSD) 

to 15 parts per million (ultra-low sulfur diesel, or ULSD). 

• Tier 2 Tailpipe. US EPA’s Tier 2 is a fleet averaging program, modeled after the California 

LEV II standards. Manufacturers can produce vehicles with emissions ranging from 

relatively dirty to zero, but the mix of vehicles a manufacturer sells each year must have 

average NOx emissions below a specified value. 

• Large Spark Ignition and Recreational Vehicle Rule. In this rule, US EPA sets emission 

standards for these categories of non-road engines and vehicles. 

• Non-Road Diesel Rule. In this rule, US EPA implements a low-sulfur fuel requirement that 

affects both future (Commercial Marine Vessels) CMV and locomotive emissions. 

• Combustion Turbine MACT. US EPA issued this rule; however, the projection inventories do 

not include the NOx co-benefit effects resulting from this rule. EPA estimates them to be 

small compared to the overall inventory. 

• Industrial Boiler/Process Heater/RICE MACT. The Environmental Protection Agency (EPA) 

issued final rules to substantially reduce emissions of toxic air pollutants from industrial, 

commercial and institutional boilers, process heaters and from stationary reciprocating 

internal combustion engines (RICE). These rules reduce emissions of a number of toxic air 

pollutants, including hydrogen chloride, manganese, lead, arsenic and mercury by 2009. 

This rule also reduces emissions of sulfur dioxide and particulate matter in conjunction with 

the toxic air pollutant reductions. The applied Maximum Achievable Control Technology 

(MACT) control efficiencies were 4 percent for SO2 and 40 percent for PM10 and PM2.5. 

However, EPA’s industrial boiler MACT rules were vacated on June 8, 2007. The emissions 
Georgia Regional Haze State Implementation Plan 

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reductions that were modeled to account for the industrial boiler MACT were 1,343.5 

tons/year of SO2, 879.4 tons/year of PM2.5, and 1,304.2 tons/year of PM10. These 

reductions are insignificantly small (0.69% for SO2, 0.39% for PM2.5, and 0.13% for PM10) 

compared to the statewide totals (193,665.5 tons/year SO2; 225,104.5 tons/year PM2.5; 

and 1,002,873.2 tons/year PM10) and should not impact the conclusions made in the SIP. If 

another VISTAS “best and final” modeling run is performed, it will remove control 

assumptions solely due to this MACT rule. 

• VOC 2-, 4-, 7-, and 10-year MACT Standards. The point source MACTs and associated 

emission reductions were designed from Federal Register (FR) notices and discussions with 

EPA’s Emission Standards Division (ESD) staff. We did not apply reductions for MACT 

standards with an initial compliance date of 2001 or earlier, assuming that the effects of 

these controls are already accounted for in the 2002 inventories supplied by the States. 

• Georgia Rule 391-3-1-.02(2)(yy), (i.e. Emissions of Nitrogen Oxides from Major sources 

based on Section 182 of the Federal CAA Amendments of 1990, requires that every major 

source (i.e. source with potential to emit > 50 tons/yr) of NOx located in 13 county Atlanta 

non-attainment area should apply reasonably available control technology (RACT) in 

controlling NOx emissions. Georgia EPD has required full compliance with NOx RACT limits 

since July 31, 1995; however, Georgia EPD has not taken these emission reductions into 

account in any inventory or modeling scenario. 

• 1-hr Ozone SIPs (Atlanta/Birmingham/Northern Kentucky). These SIPs have been 

implemented for attainment and maintenance of the 1-hour ozone National Ambient Air 

Quality Standard (NAAQS). Reductions from these SIPs have been taken into account in 

the 2018 modeling runs. 

• Georgia Rule 391-3-1-.02(2)(sss), Multipollutant Control for Electric Utility Steam Generating 

Units, was adopted in 2007. The effective date of the rule varies for various EGU units but 

will start being effective from December 31, 2008, and required controls for all affected units 

will be in place before June 1, 2015. When fully implemented, Rule (sss) will reduce SO2 

emissions by about 90 percent, NOx emissions by approximately 85 percent and mercury 

emissions by approximately 79 percent. 

7.2.2 Additional State Programs to Reduce Emissions 

In addition to accounting for specific emission reductions due to ongoing air pollution 

programs as required under the RHR Section 308 (d)(3)(v)(A), states are also required 

to consider the air quality benefits of measures to mitigate the impacts of construction 

activities [Section 308(d)(3)(v)(B)] and agricultural and forestry smoke management 

[Section 308(d)(3)(v) (E)]. 

7.2.3 Projected 2009 and 2018 Base G4 Emissions Inventories 

The Base G inventories for 2009 and 2018 account for post-2002 emission reductions 

from promulgated and proposed federal, state, local, and site-specific control programs 

as of July 1, 2004. In general, emissions inventories were developed for 2009 and 2018 

using current control information in Georgia and for growing the 2002 inventory using 

EGAS6, MOBILE6, and IPM for electric generating units (EGUs). 
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For EGUs, IPM results were adjusted based on State and local (S/L) agency knowledge 

of planned emission controls at specific EGUs, including controls required by Georgia’s 

Rule (sss). These updates for Base G4 are documented in the MACTEC emissions 

inventory report “Documentation of the 2002 Base Year and 2009 and 2018 Projection 

Year Emission Inventories for VISTAS” dated February 2007.

For non-EGUs, we used recently updated growth and control data consistent with the 

data used in US EPA’s CAIR analyses supplemented by State and local agency data 

and updated forecasts from the Department of Energy (DOE). 

Area source controls were estimated using known state-level, Stage I controls on 

gasoline dispensing facilities and open burning estimates, as well as controls used to 

project emissions for US EPA’s Heavy Duty Diesel rulemaking and for the CAIR 

rulemaking. 

Mobile source controls included local controls underlying the 2002 baseline inventory 

(vehicle emission inspection, Stage II vapor recovery, anti-tampering, etc.) with changes 

based on specific State input. Non-road control data and projections for 1996, 2010, 

2015, and 2020 were obtained from the US EPA's Clean Air Interstate Rule (CAIR) 

Technical Support Document, and straight line projections were used to estimate 2009 

and 2018 levels. 

The following bar charts show expected decreases in emissions of SO2 and NOx 

across the VISTAS states from 2002 through 2018. (Similar charts for other visibilityimpairing pollutants are contained in Appendix H). Note that for SO2 emissions in 

particular, which are the largest contributors to haze, emissions from electric generating 

facilities are expected to decrease dramatically (70 percent) between 2002 and 2018. 

However, even with this significant reduction in SO2 emissions, EGU emissions are 

projected to remain the largest contributor to haze, comprising more than half of 

remaining SO2 emissions in most of the VISTAS states. 
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Figure 7.2.3-1. Base G Annual SO2 emissions for 2002, 2009, and 2018 in the VISTAS states. 

Figure 7.2.3-2. Base G Annual NOx emissions in 2002, 2009, and 2018 in the VISTAS States. 

0

100

200

300

400

500

600

700

Alabama

Florida

Georgia

Kentucky

Mississippi

North Carolina

South Carolina

Tennessee

Virginia

West Virginia

Annual SO2 (Thousand Tons)

Miscellaneous

Nonroad

Onroad

Industrial

Other Fuel Combustion

EGU

2002 Typical

2009 OTW

2018 OTW

0

200

400

600

800

1,000

1,200

Alabama

Florida

Georgia

Kentucky

Mississippi

North Carolina

South Carolina

Tennessee

Virginia

West Virginia

Annual NOx (Thousand Tons)

Miscellaneous

Nonroad

Onroad

Industrial

Other Fuel Combustion

EGU

2002 Typical

2009 OTW

2018 OTW
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Summary of Final Base G4 Emissions Inventories for 2009 and 2018

Table 7.2.3-1 is a summary of the 2009 Base G4 emission inventory. The complete 

inventory and discussion of the methodology is contained in Appendix C. 

Table 7.2.3-1. 2009 Emissions Inventory Summary for Georgia. 

VOC NOx PM2.5 PM10 NH3 SO2 

Point 36,430.1 148,849.7 29,889.7 40,993.6 4648.8 462,666.4

Area 306,337.3 51,925.0 169,011.4 840,244.9 91,439.1 60,604.0

On-Road 

Mobile 

195,125.2 209,349.2 3,840.1 6,072.0 12,686.9 1,585.0 

Non-Road 

Mobile 

67,686 85,732.9 7,174.6 7,521.1 67.5 2,724.7 

Biogenics 1,972,795.4 20,942.38 0 0 0 0 

TOTAL 2,578,374 516,799.18 209,915.8 894,831.60 108,842.3 527,580.1

Table 7.2.3-2 is a summary of the 2018 Base G4 emission inventory. The complete 

inventory and discussion of the methodology is contained in Appendix C. 

Table 7.2.3-2. 2018 Emissions Inventory Summary for Georgia. 

VOC NOx PM2.5 PM10 NH3 SO2 

Point 43,097.8 125,680.0 36,297.4 48,005.1 6,474.4 127,863.6 

Area 353,224.5 55,518.5 180,697.2 944,009.4 102,112.4 62,636.2 

On-Road 

Mobile 

109,763.3 102,179.2 2,380.2 4,843.6 14,873.2 1,457.0 

Non-Road 

Mobile 

56,760.7 64,578.8 5,729.7 6,015.1 78.6 1,708.8 

Biogenics 1,972,795.4 20,942.38 0 0 0 0 

TOTAL 2,535,641.7 368,898.88 225,104.5 1,002,873.2 123,538.6 193,665.6 

7.2.4 Model Results for the 2018 Base G4 Inventory Compared to the Uniform 

Rate of Progress Glidepaths for Georgia Class I Areas 

Using 2000 - 2004 IMPROVE monitoring data, the deciview values for the 20 percent 

best days in each year are averaged together, producing a single average deciview 

value for the best days. Similarly, the deciview values for the 20 percent worst days in 

each year are averaged together, producing a single average deciview value for the 

worst days. 

Figures 7.2.4-1 through 7.2.4-6 illustrate the predicted visibility improvement by 2018 

resulting from the Base G4 inventory that represents implementation of existing Federal 

and State regulations, compared to the Uniform Rate of Progress glidepath for Cohutta 

Wilderness Area (COHU), Okefenokee Wilderness Area (OKEF), and Wolf Island 

Wilderness Area (WOLF). The pink lines show the target natural condition in 2064 for 

the 20 percent worst days or 20 percent best days, and the incremental deciview 

changes resulting from a uniform rate of progress between current and natural 

conditions in 2064 for average 20 percent worst visibility days or 20 percent best 
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visibility days in the 2000-2004 baseline period. The purple lines show the improvement 

expected from existing and planned emission controls during the period of the first longterm strategy. 

Figure 7.2.4-1. CMAQ 2018 Base G4 results compared to Uniform Rate of Progress at Cohutta 

Wilderness Area 

Figure 7.2.4-2. CMAQ 2018 Base G4 results compared to Uniform Rate of Progress at Okefenokee 

Wilderness Area 

Uniform Rate of Progress Glide Path

Cohutta - Worst 20% Data Days

New IMPROVE Equation

30.25

28.63

25.71

22.46

19.22

15.97

12.73

10.78

27.05

22.80

0

5

10

15

20

25

30

35

2000 2004 2008 2012 2016 2020 2024 2028 2032 2036 2040 2044 2048 2052 2056 2060 2064

Year

Haziness Index (Deciviews)

Glide Path Natural Condition (Worst Days) Observation Model Prediction

Uniform Rate of Progress Glide Path

Okefenokee - Worst 20% Data Days

New IMPROVE Equation

27.13 25.81

23.42

20.76

18.11

15.45

12.80

11.21

25.38

23.82

0

5

10

15

20

25

30

35

2000 2004 2008 2012 2016 2020 2024 2028 2032 2036 2040 2044 2048 2052 2056 2060 2064

Year

Haziness Index (Deciviews)

Glide Path Natural Condition (Worst Days) Observation Model Prediction
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Reasonable Progress Assessment Base G4 inventory, 

new IMPROVE Algorithm

Cohutta - Best 20% Days

13.77 13.77 13.77

13.01

11.75

4.32

0

5

10

15

20

25

30

35

2000 2004 2008 2012 2016 2020 2024 2028 2032 2036 2040 2044 2048 2052 2056 2060 2064

Year

Haziness Index (Deciviews)

Baseline Natural Condition (20% Best Days) Observation Method 1 Prediction

Figure 7.2.4-3. CMAQ 2018 Base G4 results compared to Uniform Rate of Progress at wolf Island 

Okefenokee Wilderness Area represents visibility improvement at Wolf Island

Figure 7.2.4-4. CMAQ 2018 Base G4 results at Cohutta Wilderness Area. 

Uniform Rate of Progress Glide Path

Wolf Island - Worst 20% Data Days

New IMPROVE Equation

27.13 25.81

23.42

20.76

18.11

15.45

12.80

11.21

25.38

23.82

0

5

10

15

20

25

30

35

2000 2004 2008 2012 2016 2020 2024 2028 2032 2036 2040 2044 2048 2052 2056 2060 2064

Year

Haziness Index (Deciviews)

Glide Path Natural Condition (Worst Days) Observation Model Prediction
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Figure 7.2.4-5. CMAQ 2018 Base G4 results at Okefenokee Wilderness Area. 

Figure 7.2.4-6. CMAQ 2018 Base G4 results at Wolf Island. 

Okefenokee Wilderness Area represents visibility Improvement at Wolf Island. 

Reasonable Progress Assessment Base G4 inventory, 

new IMPROVE Algorithm

Okefenokee - Best 20% Days

15.23 15.23 15.23

14.25 13.92

5.31

0

5

10

15

20

25

30

35

2000 2004 2008 2012 2016 2020 2024 2028 2032 2036 2040 2044 2048 2052 2056 2060 2064

Year

Haziness Index (Deciviews)

Baseline Natural Condition (20% Best Days) Observation Method 1 Prediction

Reasonable Progress Assessment Base G4 inventory, 

new IMPROVE Algorithm

Okefenokee - Best 20% Days

15.23 15.23 15.23

14.25 13.92

5.31

0

5

10

15

20

25

30

35

2000 2004 2008 2012 2016 2020 2024 2028 2032 2036 2040 2044 2048 2052 2056 2060 2064

Year

Haziness Index (Deciviews)

Baseline Natural Condition (20% Best Days) Observation Method 1 Prediction
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Note that at Cohutta wilderness area in Georgia, visibility improvement on the 20 

percent worst days is expected to be better than the uniform rate of progress glidepath 

by 2018 based solely on reductions from existing and planned emissions controls. A 4.4 

dv improvement in visibility would meet uniform rate of progress in 2018; expected 

emissions reductions by 2018 are projected to achieve a 7.41 dv improvement. 

Okefenokee Wilderness Area and Wolf Island expected emissions reductions by 2018 

are projected to achieve a 3.28 dv of improvement in visibility, while a 3.6 dv of 

improvement in visibility would meet uniform rate of progress in 2018. 

 

In Figure 7.2.4-7 the percentage of the target reduction achieved for the Georgia Class I 

areas using the new IMPROVE equation is 90-170 percent. This means that the rate of 

improvement is between –10 to +70 percent of the required uniform rate of progress by 

2018. 

In addition to improving visibility on the 20 percent worst visibility days, states are also 

required to protect visibility on the 20 percent best days at the Class I areas. As 

illustrated in Figure 7.2.4-8, visibility on the 20 percent best days is projected to improve 

in 2018 at all VISTAS Class I areas as a result of the 2018 Base G4 emissions 

reductions. In Figure 7.2.4-8 the percentage of the target achieved for the Georgia 

Class I areas is about -10 percent. Zero percent change would mean no change in 

visibility; -10 percent means that visibility is better than no change, or a 10 percent 

improvement (values lower than current conditions). 

 

The expected change in visibility at any VISTAS and neighboring class I areas between 

2000-2004 baseline conditions on the 20 percent worst days and 2018 projections for 

Base G4 is illustrated in Figure 7.2.4-7. In contrast, natural background visibility 

conditions for the 20 percent best days are illustrated in Figure 7.2.4-8. 
Georgia Regional Haze State Implementation Plan 

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CMAQ 2018g4a/2002gt2a Method 1 predictions for VISTAS+ sites

0%

20%

40%

60%

80%

100%

120%

140%

160%

180%

200%

220%

COHU1

DOSO1

GRSM1

JARI1

LIGO1

CADI1

MACA1

SHEN1

SHRO1

SIPS1

CHAS1

EVER1

OKEF1

ROMA1

SAMA1

SWAN1

BRET1

BRIG1

CACR1

HEGL1

MING1

UPBU1

Percent of target reduction achieved

CMAQ New IMPROVE Algorithm

CMAQ Old IMPROVE Algorithm

VISTAS non-VISTAS

CMAQ 2018g4a/2002gt2a Visibility Projection for VISTAS+ sites on Best 20% days -50%

-40%

-30%

-20%

-10%

0%

10%

20%

30%

40%

50%

COHU1

DOSO1

GRSM1

JARI1

LIGO1

CADI1

MACA1

SHEN1

SHRO1

SIPS1

CHAS1

EVER1

OKEF1

ROMA1

SAMA1

SWAN1

BRET1

BRIG1

CACR1

HEGL1

MING1

UPBU1

Percent of target reduction achieved

CMAQ New IMPROVE Algorithm

CMAQ Old IMPROVE Algorithm

VISTAS non-VISTAS

Figure 7.2.4-7. Projected visibility improvement on 20 percent worst visibility days at VISTAS and 

neighboring Class I areas for the 2018 Base G4 CMAQ run 

(12 km grid) 

Figure 7.2.4-8. Projected visibility improvement on 20 percent best visibility days at VISTAS and 

neighboring Class I areas for the 2018 Base G4 CMAQ run 
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Figure 7.2.4-9. Visibility improvement on 20 percent haziest days at Cohutta Wilderness Area 

between 2000-2004 baseline conditions (left) and 2018 Base G4 projected visibility (right). Image 

generated using WinHaze. 

Figure 7.2.4-10. Projected visibility on 20 percent haziest days for natural background visibility 

conditions at Cohutta Wilderness Area. Image generated using WinHaze. 
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Figure 7.2.4-9 and 7.2.4-10 show images that were generated using WINHAZE, a 

photographic imaging tool that accounts for the effect of concentrations of fine particle 

components and relative humidity on visibility. These images illustrate that notable 

improvements in visibility are expected by 2018 and that significantly greater 

improvements are needed to reach natural background conditions. 

7.3 Relative Contribution from International Emissions to Visibility Impairment in 

2018 at VISTAS Class I Areas 

Emissions from Mexico, Canada, Central America, Asia, and Africa contribute to PM2.5 

loadings and visibility impairment at Class I areas in the continental United States. To 

evaluate the relative contribution of international emissions to visibility at Class I areas 

in the southeastern United States, VISTAS used a combination of modeling results from 

the global three-dimensional chemical transport model (GEOS-Chem) and CMAQ. 

VISTAS used the GEOS-Chem global model to generate initial and boundary conditions 

for the CMAQ modeling domain. GEOS-Chem was run for the 2002 modeling year 

using a 4x5 degree horizontal grid resolution and a 3-hour temporal resolution. 

Because emissions were based on monthly averages, the model does not capture the 

episodic variability in emissions. The GEOS-Chem outputs were used to calculate 

initial and boundary conditions for the national CMAQ modeling domain. The national 

CMAQ domain included portions of Canada and Mexico, so emissions for these 

countries were included within the national CMAQ modeling domain or as part of the 

boundary conditions outside the national modeling domain, as appropriate. 

Two complementary methods were used to calculate the impact of international 

emissions at Class I areas. Because all international fires are treated as natural 

emissions in these runs, both cases underestimate the contributions from international 

fires that are due to anthropogenic burning. 

1) International emissions are represented by the differences between two GEOSChem runs. In the first run, United States anthropogenic emissions were 

removed, and in the second run both United States and international 

anthropogenic emissions were removed. The difference represents international 

anthropogenic emissions in the absence of United States anthropogenic 

emissions (e.g. compared to 2064 levels). Harvard University provided GEOSChem results to VISTAS for 2002 international contribution on 4x5 degree grid. 

Concurrently, Harvard modeling for the Electric Power Research Institute (EPRI) 

provided GEOS-Chem results for 2001 international contribution on a 1x1 degree 

grid scale. 

2) International emissions are represented by the difference between two CMAQ 

36-km simulations, both using 2018 Base F emissions and boundary conditions 

from GEOS-Chem. In the first CMAQ run, all global natural and anthropogenic 

emissions in 2018 are active. In the second CMAQ run, only global (United 

States and international) natural emissions are active. Here the impacts of 
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Transboundary Man-Made Impacts

0.0

0.2

0.4

0.6

0.8

1.0

1.2

BRIG

HEGL

CACR

MING

UPBU

BRETEVER

CHAS

SAMA

COHU

OKEF

ROMA

SIPS

SHRO

GRSM

LIGO

MACASWAN

JARI

DOSO

SHEN

(NH4)2SO4 Conc. (

μg/m3

)

GEOS_4x5 GEOS_1x1 PSAT CMAQ

international emissions are compared against 2018 conditions rather than natural 

background conditions. 

Separate from VISTAS, the CENRAP RPO used PM Source Apportionment 

Technology (PSAT) in the CAMx regional air quality model to calculate the impact of 

Canadian and Mexican emissions and boundary conditions on visibility at Class I 

areas in 2002. 

As illustrated in Figure 7.3-1 for annual average contributions to sulfate at VISTAS 

and neighboring Class I areas, the estimated international contributions are higher at 

Class I areas near the Canadian and Mexican borders and along the eastern coast. 

The estimated international contribution is higher using CMAQ and PSAT than in the 

GEOS-Chem runs because the grid scale is finer (more accurate dispersion of 

emissions) and because the background atmosphere includes loadings from current 

United States anthropogenic emissions (greater photochemical activity). Similar 

charts for nitrate and organic carbon mass, for impacts on 20 percent worst visibility 

days, and for impacts of international emissions on calculated light extinction are 

included in Appendix I. 

 

Figure 7.3-1. Estimated international emissions contributions to sulfate at VISTAS and 

neighboring Class I areas. 

In Figure 7.3-2 and 7.3-4 CMAQ projections of contributions from international 

emissions to PM mass on 20 percent worst visibility days in 2002 at Cohutta and 

Okefenokee are compared to United States domestic contributions to PM components 

at the site on those days. Figure 7.3-3 and 7.3-5 illustrates the effect of removing the 

incremental contribution due to international emissions when considering the visibility 

improvement in 2018 compared to the uniform rate of progress at Cohutta and 

Okefenokee wilderness area. Since there is not an IMPROVE monitor located at Wolf 
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Island, the Okefenokee uniform rate of progress glide slope and reasonable progress 

goals are being used as surrogates for Wolf Island. 

Figure 7.3-2. PM component concentrations from US domestic sources on 20 percent worst 

visibility days in 2002 (left bars) and CMAQ-simulated international contributions (right bars) at 

Cohutta Wilderness Area, GA. 

COHU1

Domestic and International Aerosol Mass by Species

20% Worst Days (2002)

0

10

20

30

40

50

60

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

2/25 5/2 6/1 6/4 7/4 7/7 7/10 7/16 7/25 8/3 8/6 8/9 8/12 8/15 8/21 9/5 9/8 9/17 9/20 9/23 10/8

Mass (μg/m3

)

Amm SO4 Amm NO3 POM LAC Soil CM Sea Salt
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Figure 7.3-3. Accounting for international emissions contributions on modeled rate of progress by 

2018 at Cohutta, GA. Open triangle = estimate with all emissions; Open diamond = estimate with 

international emissions removed. 

Figure 7.3-4. PM component concentrations from US domestic sources on 20 percent worst 

visibility days in 2002 (left bars) and CMAQ-simulated international contributions (right bars) at 

Okefenokee Wilderness Area, GA. 

OKEF1

Domestic and International Aerosol Mass by Species

20% Worst Days (2002)

0

5

10

15

20

25

30

35

40

45

50

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

Domestic

International

1/17 1/23 2/13 2/25 3/30 4/5 5/2 5/8 6/4 7/7 7/16 7/19 8/6 8/24 9/11 9/17 9/20 10/8 10/23 11/4 12/4 12/7 12/16

Mass (μg/m3

)

Amm SO4 Amm NO3 POM LAC Soil CM Sea Salt

Uniform Rate of Progress Glide Path

Cohutta - Worst 20% Data Days

New IMPROVE Equation

30.25 28.96

25.71

22.46

19.22

15.97

12.73

10.78

23.19

21.77

0

5

10

15

20

25

30

35

2000 2004 2008 2012 2016 2020 2024 2028 2032 2036 2040 2044 2048 2052 2056 2060 2064

Year

Haziness Index (Deciviews)

Glide Path Natural Condition (Worst Days) Observation Model Prediction Model Prediction w/o Intl. Trans.
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Figure 7.3-5. Accounting for international emissions contributions on modeled rate of progress by 

2018 at Okefenokee, GA. Open triangle = estimate with all emissions; Open diamond = estimate 

with international emissions removed. 

For the Okefenokee Class I areas, it can be seen that accounting for the international 

contribution along with reductions of United States anthropogenic emissions will result 

in visibility improvement greater than the uniform rate of progress by 2018. As the 

atmosphere becomes closer to natural background conditions in the future, the 

incremental contribution from international emissions will become more important. The 

information is included in this SIP documentation to provide reference for future 

assessments of reasonable progress. 

7.4 Relative Contributions to Visibility Impairment: Pollutants, Source Categories, 

and Geographic Areas 

An important step toward identifying further reasonable progress measures is to identify 

the key pollutants contributing to visibility impairment at each Class I area. To 

understand the relative benefit of further reducing emissions from different pollutants, 

source sectors, and geographic areas, VISTAS engaged the Georgia Institute of 

Technology to perform emission sensitivity model runs using CMAQ. Emissions 

sensitivities were initially performed for three episodes representing winter and summer 

conditions: January 2002, July 2001, and July 2002. These runs used the initial 2018 

projections inventory and considered 30 percent reductions from specific pollutants, 

source categories, and geographic areas. Emissions sensitivities were repeated using 

the 2009 Base D projection inventory and two-month-long episodes from 2002: June 1-

Uniform Rate of Progress Glide Path

Okefenokee - Worst 20% Data Days

New IMPROVE Equation

27.13 26.07

23.42

20.76

18.11

15.45

12.80

11.21

24.37

22.64

0

5

10

15

20

25

30

35

2000 2004 2008 2012 2016 2020 2024 2028 2032 2036 2040 2044 2048 2052 2056 2060 2064

Year

Haziness Index (Deciviews)

Glide Path Natural Condition (Worst Days) Observation Model Prediction Model Prediction w/o Intl. Trans.
Georgia Regional Haze State Implementation Plan 

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July 10 and November 19 through December 19. Emissions in 2009 were reduced by 

30 percent for each pollutant sensitivity run. The pollutant contributions that were 

evaluated were: 

• SO2 from EGU sources in each VISTAS state, other RPOs in the VISTAS 12 km 

grid, and Boundary Conditions from outside the 12 km domain; 

• SO2 from non-EGU point sources in each VISTAS state, other RPOs, and 

Boundary Conditions; 

• NOx from ground level (on-road plus non-road plus area) sources in each 

VISTAS state and other RPOs; 

• NOx from point (EGU plus non-EGU) sources in each VISTAS state and other 

RPOs; 

• NH3 from all sources in VISTAS and other RPOs; 

• Volatile Organic Compounds from anthropogenic and biogenic sources in the 12 

km modeling domain; 

• Primary Carbon from all ground level sources in each VISTAS state and other 

RPOs; 

• Primary Carbon from all point sources in each VISTAS state and other RPOs; 

and 

• Primary Carbon from all fires in each VISTAS state and other RPOs. 
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Results are shown in Figures 7.4-1 through 7.4-2 below for the average of the 20 

percent worst visibility days for the two Georgia Class I areas. 

Figure 7.4-1. CMAQ projections of visibility responses on 20 percent worst days at Cohutta 

Wilderness Area, GA to 30 percent reductions from the 2009 Base D inventory for visibilityreducing pollutants in different source categories and geographic areas. 

Figure 7.4-2. CMAQ projections of visibility responses on 20 percent worst days at Okefenokee 

Wilderness Area, GA to 30 percent reductions from the 2009 Base D inventory for visibilityreducing pollutants in different source categories and geographic areas. 
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Responses for 20 percent worst days were calculated by averaging the responses of 

the 20 percent worst days that were modeled in the two episodes. For the Georgia 

sites, responses on five-to-six of the 20 percent worst visibility days were included in 

these graphics. 

As Figures 7.4-1 through 7.4-2 illustrate, the greatest visibility benefits on the 20 percent 

worst days for the Georgia Class I areas are projected to result from further reducing 

SO2 from EGUs. At the mountain Class I areas, benefits are projected from SO2 

reductions from EGUs in several VISTAS states including Alabama, Georgia, Kentucky, 

North Carolina, South Carolina, Tennessee, Virginia, and West Virginia. Contributions 

from other RPOs and from the boundary conditions are comparatively small and the 

greatest benefits would likely be from further EGU reductions within the VISTAS states. 

MRPO states have some contribution, as do SO2 and SO4 coming into the modeling 

domain from outside the boundary. 

Additional, smaller benefits are projected from additional SO2 emission reductions from 

non-utility, industrial point sources. The pattern of relative SO2 contributions from nonEGUs among the various VISTAS states is similar to the pattern of relative SO2 

contributions from EGUs. 

Because ammonium nitrate is a small contributor to PM2.5 mass and visibility 

impairment on the 20 percent worst days at the mountain Class I areas, the benefits of 

reducing NOx and NH3 emissions at these sites are small. Some of the 20 percent 

worst days at coastal sites in the VISTAS states occur in the winter when ammonium 

nitrate has a somewhat larger contribution to visibility impairment. As shown in Figure 

7.4-2, reducing ammonia emissions would be more beneficial for reducing ammonium 

nitrate contributions to visibility impairment at Okefenokee Wilderness area than further 

reducing nitrogen oxide emissions from either ground or point sources. Ammonium 

emissions are the result of agricultural activity, specifically fertilizing operations and 

animal farming. Since there are no economically feasible options for controlling these 

types of area sources of ammonia emissions, and EPD lacks authority over agricultural 

activities, no further consideration was given. 

VOCs do contribute to visibility impairment, but as shown in the charts above, this 

contribution is from biogenic sources such as vegetative emissions. Controlling 

anthropogenic sources of VOC emissions has little, if any, visibility benefit at the Class I 

areas. Reducing primary carbon from point sources, ground level sources or fires are 

projected to have small to no visibility benefit. This is consistent with the monitoring 

data that shows that most of measured organic carbon is secondary in origin and 

primary carbon is only a small fraction of the total measured carbon (Appendix B). 

Reducing carbon from fires was not found to be effective because there was little fire 

activity at these sites on the days modeled in the sensitivity analyses. 

Note that these results from the emission sensitivity runs are consistent with the 

conclusions drawn from the 2000-2004 baseline monitoring data (see Section 2.4 

above). The results indicate that sulfate is the dominant contributor to visibility 
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impairment on the 20 percent worst days at all sites, and that ammonium nitrate may be 

important for sites where the 20 percent worst days occur in the winter. We conclude 

that reducing SO2 emissions from EGU and non-EGU point sources in the VISTAS 

states would have the greatest visibility benefits for the GA Class I areas. Contributions 

from the Midwest RPO and MANE-VU are greater at the Class I areas bordering these 

RPOs. Contributions from outside the VISTAS 12-km modeling domain are more

important for the coastal Class I areas. These results are consistent with the CMAQ 

model results indicating that contributions from international emissions to visibility 

impairment at VISTAS Class I areas are greater closer to the boundaries of the 

modeling domain (see summary in Section 7.3 and further discussion in Appendix I). 

7.5 Relative Contributions to Visibility Impairment: Geographic Areas of Influence 

for Georgia Class I Areas 

Once it was determined that SO2 emission reductions from EGU and non-EGU point 

sources in the VISTAS states would be the most effective sources to control to improve 

visibility at the Georgia Class I areas and non-Georgia Class I areas impacted by 

Georgia sources, the next step was to identify the specific geographic areas that most 

likely influence visibility in each Class I area, and then to identify the major SO2 point 

sources located in those geographic areas. An SO2 Area of Influence (AoI) was 

defined for each Class I area to represent the geographic area containing sources that 

would likely have the greatest impact on visibility at that Class I area. All SO2 point 

sources within these Areas of Influence were identified and ranked by their 2018 Base 

G4 emissions. The following sections contain a broad overview of the steps in the Area 

of Influence analyses. See Appendix H for a more detailed discussion of these 

analyses and plots for additional Class I areas. 

7.5.1 Back Trajectory Analyses 

The first step was to generate meteorological back trajectories for IMPROVE monitoring 

sites in Georgia and neighboring Class I areas for the 2000-2004 baseline period. Back 

trajectory analyses use interpolated measured or modeled meteorological fields to 

estimate the most likely central path of air masses that arrive at a receptor at a given 

time. The method essentially follows a parcel of air backward in hourly steps for a 

specified length of time. Figure 7.5.1-1 is an example of a back trajectory analysis for 

Cohutta Wilderness Area for the 20 percent worst days in 2002. 
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Figure 7.5.1-1. Example back trajectories for 20 percent worst visibility days in 2002 for Cohutta 

Wilderness Area. 

Trajectories were started at 100 meters and 500 meters above the surface and run 

backward from the site for 72-hours. These individual back trajectories for 20 percent 

worst days in 2002 were also useful in evaluating model performance for individual days 

at the Class I areas.

7.5.2 Residence Time Plots 

The next step was to plot residence time for each Class I area using five years of back 

trajectories for the 20 percent worst visibility days in 2000-2004. Residence time is the 

frequency that winds pass over a specific geographic area on the path to a Class I area. 

Separate residence time plots were generated using trajectories with 100m and 500m 

start heights. 
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As illustrated in Figure 7.5.2-1, winds influencing Cohutta Wilderness Area on the 20 

percent worst days come from all directions, and there is no single predominant wind 

direction influencing the 20 percent worst visibility days. 

Figure 7.5.2-1. Example residence time plot for 20 percent worst visibility days in 2000-2004 for 

Cohutta Wilderness Area. Based on trajectories with 100m start height. 

7.5.3 SO2 Areas of Influence 

The next step was to develop sulfate extinction weighted residence time plots to define 

the geographic area with highest probability of influencing the receptor on the 20 

percent worst days in 2000-2004 that were dominated by sulfate. Each back trajectory 

was weighted by sulfate extinction for that day. This allows us to focus on the 20 

percent worst days that are influenced by sulfate and place less importance on days 

influenced by organic carbon from fires. Sulfate-weighted back trajectories for the 20 

percent worst days were combined for five years of data. The resulting sulfate 

extinction-weighted residence time plots were used to define the geographic Area of 

Influence for sources of SO2 emissions. In Figure 7.5.3 the area representing 10 

percent or greater residence time is outlined in red and the area representing five 

percent or greater residence time is outlined in orange. The VISTAS states focused 

their analyses on the Area of Influence defined by five percent or greater sulfate 

extinction-weighted residence time. 
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Figure 7.5.3-1. Example SO2 Area of Influence plot for sulfate extinction weighted residence time 

for 20 percent worst visibility days in 2000-2004 for Cohutta Wilderness Area, Georgia. Based on 

trajectories with 100m start height.

7.5.4 Emissions Sources within SO2 Areas of Influence 

Residence time plots were then combined with geographically-gridded emission data 

based on the 2002 baseline and 2018 BaseG emissions inventories. Plots were 

generated for the Areas of Influence defined by trajectories with 100m and 500m start 

heights. As a way of incorporating the effects of transport, deposition, and chemical 

transformation of point source emissions along the path of the trajectories, these data 

were weighted by 1/d, where “d” was calculated as the distance, in kilometers, between 

the center of the grid cell in which a source is located and the center of the grid cell in 

which the IMPROVE monitor is located. The distance-weighted point source SO2 

emissions are then combined with the gridded extinction-weighted back-trajectory 

residence times at a spatial resolution of 36-km. 

The final step was to combine the residence times and gridded emissions data in plots 

and data sets. The distance weighted (1/d) gridded point source SO2 emissions were 

multiplied by the total extinction-weighted back-trajectory residence times on a grid cell 

by grid cell basis. These results were then normalized by the domain-wide total and 

displayed as a percentage. The analysis was done using both the 2002 and 2018 base 

year inventories. 
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Figures 7.5.4-1 illustrates 2002 and 2018 distance weighted gridded emissions “x” 

sulfate extinction weighted residence time plots for Cohutta Wilderness Area. These 

maps help visualize where the emissions reductions will be occurring between 2002 and 

2018. The change in SO2 emissions between 2002 and 2018 can be seen by 

comparing emissions source strengths in the two plots. Note the emissions from each 

source are normalized by the total emissions in the domain. Sources that reduce SO2 

emissions by 2018 will show a lower contribution to emissions in the domain. On the 

2018 map the grid cells with these sources will show a lighter color gradient than on the 

2002 map. For example: SO2 reductions from EGUs in north and central Georgia can 

be seen by comparing the 2002 and 2018 maps. Because the total emissions in the 

domain are smaller in 2018, a source that does not change emissions between 2002 

and 2018 may actually appear to increase in importance in 2018 compared to 2002. 

Figure 7.5.4-1. Cohutta Wilderness Area 2002 and 2018 SO2 distance weighted emissions x SO4 

extinction-weighted residence time plots. 

Figure 7.5.4-2 illustrates gridded SO2 distance weighted emission’s sulfate “x” 

extinction weighted residence time plots for 2018 emissions for Okefenokee Wilderness 

Area. The plot illustrates the relative importance of Georgia sources of SO2 compared 

to sources in neighboring states. Additional analyses, including 2002 and 2018 

distance weighted emissions “x” residence time plots for the Class I areas in Georgia 

are contained in Appendix H. 
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Figure 7.5.4-2. 2018 SO2 distance weighted emissions x SO4 extinction-weighted residence time 

plot for Okefenokee, Georgia. 
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Finally, Table 7.5.4-1 shows, the relative contributions of point source SO2 emissions 

from nearby states to Georgia Class I areas. 

Table 7.5.4-1. 2018 SO2 Point Source Contribution (Using RTMax*Q/d) to Georgia 

Class I Areas by State 

Georgia Class I Area 

State OKEF COHU WOLF 

Alabama 1.29% 19.04% 0.85% 

Delaware 0.29% 

Florida 74.99% 38.05% 

Georgia 16.95% 36.72% 41.88% 

Indiana 0.42 

Kentucky 1.75% 

Maryland 

New Jersey 

North Carolina 0.11% 5.16% 3.01% 

Ohio 

Pennsylvania 

South Carolina 6.66% 4.05% 15.81% 

Tennessee 31.88% 

Virginia 0.62% 0.12% 

West Virginia 0.36% 

Total 100.00% 100.00% 100.00% 
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7.5.5 Specific Source Types in the Areas of Influence for Georgia Class I Areas 

The next step in the analysis was to review the emissions inventories to determine the 

source categories, as well as specific sources, found to have the greatest impact on 

visibility in Georgia Class I areas. Lists of SO2 point sources within the Areas of 

Influence for each Class I area were developed using the Base G VISTAS 2002 base 

year and 2018 future year emissions. For this purpose the Area of Influence was 

defined as the counties with maximum sulfate extinction weighted residence time 

greater than five. For SO2 sources within each Area of Influence, the following 

attributes were defined for each individual unit: 

• State, county, and source (plant), and industry identification codes; 

• SO2 emissions for 2002 and 2018; 

• 2018 control efficiency; 

• Distance to Class I areas (defined by centroid of the Class I area); 

• Emissions divided by distance (Q/d), a metric that accounts for the dispersion of 

emissions over distance; and 

• Maximum sulfate extinction weighted residence time (RTmax).

Our review was conducted in a top-down fashion starting with an analysis of the major 

source categories in each SO2 Area of Influence to determine which major categories 

had the highest residual contribution to the area in 2018. It was also important to 

identify reductions that are projected to occur between 2002 and 2018 within each 

category or at specific units. This allowed VISTAS States to determine if certain source 

categories or units that had yet to be controlled under the future year base case had the 

potential for reduction. Once the highest source types were identified, subcategories 

within those source types were reviewed. The contributions from major source 

categories to the 2018 Base G4 inventory for the SO2 Areas of Influence for the 

Georgia Class I areas are listed in Tables 7.5.5-1 through 7.5.5-3. 
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Table 7.5.5-1. 2018 Emissions Contributions from Major Source Categories in the 

Area of Influence for Cohutta Wilderness Area. 

Table 7.5.5-2. 2018 Emissions Contributions from Major Source Categories in the 

Area of Influence for Okefenokee Wilderness Area. 

Tier VOC NOX CO SO2 PM-10 PM-2.5 NH3

Fuel Comb. Elec. Util. 0% 21% 1% 52% 9% 17% 1%

Fuel Comb. Industrial 1% 19% 2% 28% 3% 5% 0%

Fuel Comb. Other 5% 6% 3% 6% 5% 10% 1%

Chemical & Allied 

Product Mfg 2% 1% 0% 2% 1% 1% 1%

Metals Processing 1% 1% 1% 3% 2% 5% 0%

Petroleum & Related 

Industries 0% 0% 0% 1% 0% 0% 0%

Other Industrial 

Processes 7% 6% 1% 5% 9% 11% 1%

Solvent Utilization 42% 1% 0% 0% 0% 1% 0%

Storage & Transport 6% 0% 0% 0% 1% 1% 0%

Waste Disposal & 

Recycling 4% 2% 4% 0% 5% 12% 0%

Highway Vehicles 18% 25% 48% 0% 2% 2% 12%

Off-highway 11% 18% 34% 1% 2% 4% 0%

Miscellaneous 2% 1% 7% 0% 61% 30% 83%

VISTAS Total 100% 100% 100% 100% 100% 100% 100%

Tier VOC NOX CO SO2 PM-10 PM-2.5 NH3

Fuel Comb. Elec. Util. 0% 22% 1% 51% 7% 12% 1%

Fuel Comb. Industrial 1% 16% 2% 25% 3% 5% 0%

Fuel Comb. Other 3% 4% 1% 6% 2% 4% 0%

Chemical & Allied 

Product Mfg 1% 1% 0% 4% 0% 1% 0%

Metals Processing 0% 0% 0% 4% 0% 0% 0%

Petroleum & Related 

Industries 0% 0% 0% 0% 0% 0% 0%

Other Industrial 

Processes 7% 6% 1% 7% 8% 11% 2%

Solvent Utilization 39% 0% 0% 0% 0% 0% 0%

Storage & Transport 7% 0% 0% 0% 0% 0% 0%

Waste Disposal & 

Recycling 4% 3% 7% 0% 8% 16% 0%

Highway Vehicles 18% 25% 38% 1% 1% 1% 10%

Off-highway 14% 19% 29% 1% 2% 3% 0%

Miscellaneous 6% 4% 20% 1% 68% 46% 86%

VISTAS Total 100% 100% 100% 100% 100% 100% 100%
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Table 7.5.5-3. 2018 Emissions Contributions from Major Source Categories in the 

Area of Influence for Wolf Island. 

These tables indicate that for all Georgia Class I areas, EGUs and industrial boilers are 

the two major source categories contributing to 2018 SO2 emissions in the Areas of 

Influence, even after implementation of the CAMR and CAIR. Together these two 

source categories contribute 79-85 percent of the 2018 SO2 emissions for the Areas of 

Influence for the Georgia Class I areas. Other fuel combustion and other industrial 

processes comprise another 9-12 percent of the 2018 SO2 emissions. 

These tables can also be used to evaluate the major source categories contributing to 

emissions of NOx, NH3, and PM emissions in 2018. For instance, highway vehicles 

and off-road vehicles are major sources of NOx emissions, in addition to electric utilities 

and industrial boilers. The source category “miscellaneous” (which includes agricultural 

sources and fires) is the major contributor to NH3 and primary PM. The emissions 

sensitivities discussed in Section 7.4 indicated very small benefits of controlling NOx, 

NH3, and primary PM emissions at the Georgia Class I areas, but if these emissions 

were of concern, different source categories would need to be addressed. 

The contributions to SO2 emissions in 2018 from the three highest source categories, 

electric utilities, industrial boilers, and other fuel combustion have been further broken 

out into subcategories. Table 7.5.5-4 indicates subcategories for the Areas of Influence 

for the Georgia Class I areas. Within electric utilities, all the SO2 emissions are 

attributable to coal-fired power plants. Within industrial boilers, most emissions are 

attributable to coal-fired boilers with lesser contributions from oil and gas boilers. 

Commercial and institutional coal and oil boilers have smaller contributions. 

Tier VOC NOX CO SO2 PM-10 PM-2.5 NH3

Fuel Comb. Elec. Util. 0% 21% 1% 47% 7% 14% 1%

Fuel Comb. Industrial 1% 16% 2% 31% 3% 5% 0%

Fuel Comb. Other 3% 5% 2% 6% 3% 6% 1%

Chemical & Allied Product Mfg 1% 2% 0% 4% 0% 1% 1%

Metals Processing 0% 0% 0% 3% 0% 0% 0%

Petroleum & Related 

Industries 0% 0% 0% 0% 0% 0% 0%

Other Industrial Processes 6% 5% 1% 5% 7% 8% 2%

Solvent Utilization 39% 0% 0% 0% 0% 0% 0%

Storage & Transport 7% 0% 0% 0% 0% 1% 0%

Waste Disposal & Recycling 4% 3% 7% 1% 7% 16% 0%

Highway Vehicles 19% 25% 40% 1% 1% 1% 10%

Off-highway 15% 21% 32% 1% 2% 5% 0%

Miscellaneous 5% 3% 15% 1% 67% 43% 85%

VISTAS Total 100% 100% 100% 100% 100% 100% 100%
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Table 7.5.5-4. 2018 SO2 Emissions Contributions from Major Source Categories 

in the Area of Influence for GA Class I areas.

Tier W OLF OKEF COHU

Fuel Com b. Elec. Util.-Coal 45% 49% 52%

Fuel Com b. Elec. Util.-Oil 0% 0% 0%

Fuel Com b. Elec. Util.-Gas 0% 0% 0%

Fuel Com b. Elec. Util.-Other 2% 2% 0%

Fuel Com b. E lec . Util.-Internal 

Combustion 1% 0% 0%

Fuel Com b. Industrial-Coal 18% 14% 20%

Fuel Com b. Industrial-Oil 9% 8% 5%

Fuel Com b. Industrial-Gas 2% 1% 2%

Fuel Com b. Industrial-Other 2% 3% 1%

Fuel Com b. Industrial-Internal 

Combustion 0% 0% 0%

Fuel Com b. OtherCom m erc ial/Institutional Coal 2% 2% 2%

Fuel Com b. OtherCom m erc ial/Institutional Oil 3% 3% 4%

Fuel Com b. OtherCom m erc ial/Institutional Gas 0% 0% 0%

Fuel Com b. Other-Misc. Fuel 

Comb. (Except Residential) 0% 0% 0%

Fuel Com b. Other-Residential 

W ood 0% 0% 0%

Fuel Com b. Other-Residential 

Other 0% 0% 1%

These analyses indicate that GA EPD should consider what additional control measures 

for electric utilities and industrial boilers are reasonable. GA EPD also determined that 

it was appropriate to also consider additional control measures from industrial sources 

other than boilers that contributed to the same magnitude of visibility impairment as 

boilers. The lists of individual sources are also being used to determine if individual 

sources in other sources categories are major contributors. 

The next step was to identify emission reductions that have already occurred within 

each source category and at specific units. Unit level tables of emission comparisons 

from 2002 to 2018 were developed, allowing VISTAS States to review existing emission 

reductions. These tables assigned future-year control technology from IPM forecasting 

and State modification for EGUs and from control efficiency tables for Non-EGU point 

sources. 

Once emission control profiles for specific units were defined, the next step was to 

determine what, if any, additional control measures would feasibly be available and to 

evaluate these controls to determine which are reasonable. 
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For EGUs, the 2018 IPM file used by VISTAS for EGU sources was obtained and 

matched to the 2018 base-case inventory of EGU sources for most states. However, 

IPM assumptions for future controls were not consistent with the emission controls 

required for EGUS by Georgia’s Multipollutant Rule. The Georgia EGU emission 

controls are documented in the emission inventory documents found in Appendix C. 

7.6 Reasonable Progress Determinations for Individual Sources 

The following summarizes the process for determining reasonable progress for Georgia 

sources and the results of the determinations. This process was based on U.S. EPA’s 

“Guidance for Setting Reasonable Progress Goals Under the Regional Haze Program,” 

June of 2007 [Reasonable Progress guidance]. For a detailed discussion of the 

reasonable progress assessments for all emissions units contributing greater than half a 

percent of sulfate impact to any Class I area in Georgia or in neighboring states, see 

Appendix H. 

7.6.1 Process for Determining Reasonable Progress 

Step 1: Determine pollutants of concern.

VISTAS evaluated the species contribution on the 20 percent worst visibility days and 

concluded that sulfate accounted for greater than 70 percent of the visibility impairing 

pollution. The VISTAS States concluded that controlling SO2 emissions was the 

appropriate step in addressing the reasonable progress assessment for 2018. The 

VISTAS findings were consistent with the findings of SAMI. As stated previously, SAMI 

confirmed that sulfate particles account for the greatest portion of the haze affecting 

Class I areas in the Southern Appalachian region and that these sulfates were produced 

in large part from SO2 emissions from coal combustion. 

Step 2: Determine which source sectors should be evaluated for reasonable progress. 

Since SO2 point source emissions in 2018 are projected to represent greater than 95 

percent of the total SO2 emissions inventory, the VISTAS states concluded that the 

focus should be on electric generating unit (EGU) and non-EGU point sources of SO2 

emissions. 
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Step 3: Consideration of Emissions Reductions from State and Federal Control 

Measures.

64 FR 35733 states that “In determining the emissions and visibility improvement 

achieved during each implementation period, states should include all air quality 

improvements that will be achieved by other programs and activities under the CAA and 

any state air pollution control requirements.” In keeping with this recommendation, 

Georgia, as part of its long-term reasonable progress analysis to consider potential 

sources contributing to visibility impairment, examined other CAA requirements such as 

CAIR. Under Georgia’s CAIR rule for SO2 [391-3-1-.02(13)], SO2 emissions from 

Georgia EGUs will be capped at 149,140 tons in 2015, a 70 % reduction from 2002 

actual emissions. In addition, a 70 % reduction of SO2 emissions is expected during 

this time period across all CAIR-affected EGUs in 28 eastern states. Through these 

programs between the present and 2018, EPD concluded that additional EGU control 

during this time period is not reasonable for sources that significantly contribute to 

visibility impairment at Class I areas that clearly projected to meet the uniform rate of 

progress (URP) in 2018. However, for sources that significantly contribute to visibility 

impairment at Class I areas not clearly meeting the URP (such as Okefenokee and Wolf 

Island), EPD did consider additional controls at CAIR-affected units. 

For EGUs subject to CAIR, EPA evaluated a number of factors, including the cost of 

compliance and time necessary for compliance. In the CAIR rule, EPA determined “that 

the earliest reasonable deadline for compliance with the final highly cost effective 

control levels for reducing emissions was 2015...” (70 FR 25197 – 25198, May 12, 

2005). The State believes that the cost of compliance and time necessary for 

compliance are the dominant factors for determining if additional reductions would be 

reasonable from CAIR-subject EGUs. The detailed analyses in the preamble to the 

May 12, 2005, CAIR rule support a conclusion that CAIR controls satisfy reasonable 

progress for SO2 for the first regional haze planning period ending in 2018. 

The SO2 emission reductions that are predicted by the IPM to meet the CAIR 

requirements are not certain due to the current rule’s reliance on unchecked trading and 

the use of banked Title IV allowances. The GA EPD intends to re-evaluate the IPM 

predictions of SO2 reductions for CAIR for EGUs at the time of the first five-year 

periodic report [40 CFR 51.308(g)] to ensure that the reductions currently predicted by 

IPM for CAIR are in fact taking place where they are expected and needed .

The Cohutta Class I Area is expected, based on modeling, to clearly meet the glide 

slope in 2018. GA EPD has therefore concluded that CAIR constitutes reasonable 

measures for Georgia EGUs that significantly impact visibility in Cohutta during this first 

assessment period (between baseline and 2018). Because the Okefenokee, Wolf 

Island, and Saint Marks areas are not expected to clearly meet the glide slope, controls 

required under CAIR have not been deemed to constitute reasonable measures for 

Georgia EGUs that significantly impact visibility in these Class I areas. 

Georgia Power Company, in anticipation of CAIR requirements, has committed to 

implementing SO2 emission reduction measures on 22 of its EGUs. All of the 22 
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affected units are located in the northern half of the state and their predicted emissions 

reductions have been accounted for in the modeling used to predict 2018 visibility levels 

in this SIP. These reduction measures and the associated emissions reductions are 

summarized in Table 7.6.1-1. 

Table 7.6.1-1. Projected 2018 SO2 emission reductions associated with planned 

reduction measures at Georgia Power EGUs. 

Facility Unit Annual SO2 

Emissions, 

2002 (tons) 

Reduction Measure Annual SO2 

Emissions, 

2018 

(tons) * 

Annual SO2 

Reductions, 

2002 to 2018 

(tons) 

Hammond 1 3933 scrubber 269 3664 

 2 4092 scrubber 270 3822 

 3 4262 scrubber 267 3995 

 4 18088 scrubber 1728 16360 

Wansley 1 38741 scrubber 3018 35723 

 2 36421 scrubber 3022 33399 

Bowen 1 33050 scrubber 2415 30635 

 2 35266 scrubber 2432 32834 

 3 42900 scrubber 3056 39844 

 4 42634 scrubber 3147 39487 

McDonough 1 13802 convert to natural gas 578 13224 

 2 13631 convert to natural gas 596 13035 

Scherer 1 25286 scrubber 1313 23973 

 2 24966 scrubber 1304 23662 

 3 18149 scrubber 1387 16762 

 4 20771 scrubber 1331 19440 

Branch 1 10837 scrubber 618 10219 

 2 13941 scrubber 748 13193 

 3 21211 scrubber 1158 20053 

 4 22342 scrubber 1133 21209 

Yates 1 233 Existing scrubber (no 

additional reduction) 

332 -99 

 2 3991 none 3547 444 

 3 3237 none 3916 -679 

 4 4842 none 6500 -1658 

 5 5009 none 6643 -1634 

 6 15175 scrubber 818 14357 

 7 14024 scrubber 826 13198 

TOTAL 

(tons) 

 490385 52373 438012 

* Emissions reflect VISTAS plant utilization growth projections. 
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Step 4: Determine which emission units would be evaluated based on impact. 

The GA EPD calculated the projected 2018 fractional contribution from all emission 

units within the SO2 Area of Influence for a given Class I area, including contributions 

from EGUs after planned SO2 controls. EPD then identified those emission units with a 

contribution of half a percent or more to the sulfate visibility impairment at the specific 

Class I area. See section 5.0 of Appendix H for the rationale for the selection of the 

one-half percent threshold for this analysis. As noted in Step 3, SO2 controls on EGUs 

that impact visibility at Cohutta, as required by CAIR, are deemed to be reasonable 

measures. Therefore, these units were exempted from four-factor evaluation even if 

their sulfate visibility impairments were half a percent or more. 

Step 5: Evaluate the four factors. 

Each emission unit identified in Step 4 above was evaluated using the following four 

statutory and regulatory factors of 1) cost of compliance, 2) time necessary for 

compliance, 3) the energy and non-air quality environmental impacts of compliance, and 

4) the remaining useful life of the emissions unit. 

7.6.2 Sources Eligible for Four Factor Analysis in Georgia 

As part of the Regional Haze reasonable progress goal analysis, GA EPD initially 

identified 29 emission units for analysis of additional controls for meeting the reasonable 

progress requirements of the Regional Haze program in accordance with the above four 

statutory factors. The 29 units were selected based on analyses that indicated that 

each one’s contribution to total sulfate visibility impairment was at least 0.5% of the total 

sulfate visibility impairment at one or more Class I areas. The analysis for eligibility 

assumed that the units’ 2018 sulfate emissions were their VISTAS-projected emissions. 

The eligible units are listed below in Table 7.6.2-1. Details of the eligible unit selection 

process are presented in Section 5.0 of Appendix H. 
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Table 7.6.2-1. List of all facilities along with their units eligible for 4-factor 

analysis 

Four Factor Analysis – Eligible Sources Eligible Units 

Georgia Pacific Brunswick Cellulose Power Boiler No. 4 

Georgia Pacific Brunswick Cellulose Recovery Boiler (M24) 

Georgia Pacific Cedar Springs Power Boiler U500 

Georgia Pacific Cedar Springs Power Boiler U501 

Georgia Pacific Cedar Springs Recovery Boiler R402 

Georgia Pacific, Savannah River Mill Boiler B001 

Georgia Pacific, Savannah River Mill Boiler B002 

Georgia Pacific, Savannah River Mill Boiler B003 

Georgia Power Plant Kraft Steam Generator 1 

Georgia Power Plant Kraft Steam Generator 2 

Georgia Power Plant Kraft Steam Generator 3 

Georgia Power Plant Mitchell Steam Generator 3 

Georgia Power Plant McIntosh Steam Generator 1 

International Paper, Savannah Mill Power Boiler 13 

Interstate Paper Power Boiler F1 

Miller Brewing Boiler B001 

Miller Brewing Boiler B002 

Mount Vernon Mills Boiler E U 03 

Mount Vernon Mills Boiler E U 04 

Packaging Corporation of America C E Boiler 

Rayonier Performance Fibers, Jessup Mill Power Boiler 2 

Rayonier Performance Fibers, Jessup Mill Power Boiler 3 

Rayonier Performance Fibers, Jessup Mill Recovery Furnace 1 

Rayonier Performance Fibers, Jessup Mill Recovery Furnace 4 

Savannah Sugar Refinery Boiler U161 

Southern States Phosphate and Fertilizer Sulfuric Acid Plant 2 

Temple Inland Rome Linerboard Power Boiler No. 4 

Mohawk Industries Boiler BL06 

Mohawk Industries Boiler BL07 

GA EPD requested four-factor analyses from these facilities. In response to this 

request, additional information regarding projected 2018 actual emissions was received 

from a number of sources. As a result of this revised information, seven units were 

removed from consideration for additional controls based on an analysis that the 

emission units would not contribute half a percent or greater of the total sulfate visibility 

impairment at any Class I area in 2018. Those seven units are listed below in Table 

7.6.2-2. 
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Table 7.6.2-2. Units Removed from 4-Factor List Based on Facilities’ Updated 

2018 Emission Estimates 

Sources Units 

Miller Brewing Boiler B001 

Miller Brewing Boiler B002 

Mount Vernon Mills Boiler E U 03 

Mount Vernon Mills Boiler E U 04 

Savannah Sugar Refinery Boiler U161 

Mohawk Industries Boiler BL06 

Mohawk Industries Boiler BL07 

In addition, three facilities requested and have received emission limits to reduce the 

sulfate visibility impairment from each emissions unit to less than 0.5%. Those facilities 

and the affected emission units are listed below in Table 7.6.2-3. 

Table 7.6.2-3. Facilities That Requested Emission Limits 

Sources Units 

Rayonier Performance Fibers, Jessup Mill Power Boiler 2 

Rayonier Performance Fibers, Jessup Mill Power Boiler 3 

Rayonier Performance Fibers, Jessup Mill Recovery Furnace 1 

Rayonier Performance Fibers, Jessup Mill Recovery Furnace 4 

Southern States Phosphate and Fertilizer Sulfuric Acid Plant 2 

Packaging Corporation of America C E Boiler 

Furthermore, one of the emissions units is subject to Best Available Retrofit Technology 

(BART) Review under the Regional Haze Rule. In accordance with EPA’s June 1, 2007 

”Guidance For Setting Reasonable Progress Goals under the Regional Haze Program” 

(pages 4-2 and 4-3), for emissions units subject to BART, the State will already have 

completed a BART analysis. Since the BART analysis is based, in part, on an 

assessment of many of the same factors that must be addressed in establishing 

reasonable progress goals, it is reasonable to conclude that any control requirements 

imposed in the BART determination also satisfy the RPG-related requirements for 

source review in the first RPG planning period. (This exclusion does not include units at 

facilities that are exempt from BART review through screening modeling.) That 

emissions unit is Interstate Paper – Power Boiler F1. 

Therefore, 4-factor reviews were conducted on the remaining 15 emission units. 

7.6.3 Regional Haze Reasonable Progress Four-Factor Analysis 

The regional haze rule requires that states consider the following factors and 

demonstrate how these factors were taken into consideration in selecting the 

reasonable progress goal: 

• Costs of compliance; 

• Time necessary for compliance; 
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• Energy and non-air quality environmental impacts of compliance; and 

• Remaining useful life of any potentially-affected sources.

The general considerations taken into account in Georgia EPD’s 4-factor evaluations 

and the evaluations of the specific emissions units are presented below.

Costs of Compliance – General Considerations

GA EPD evaluated the cost of compliance using a variety of factors. Facilities provided 

data for various control options for each affected unit. The data typically included total 

capital costs and cost-per-ton of pollutant removed ($/ton). GA EPD compared this data 

with similarly controlled units as well as AirControlNET estimates. Costs were 

presented in 2007 dollars for consistency. In addition, GA EPD conducted CMAQ 

modeling to determine the amount of visibility improvement resulting from each ton of 

SO2 reduced from each unit subject to analysis. This cost-efficiency metric is 

expressed in dollar-per-inverse megameter ($/Mm-1) and was considered in addition to 

cost efficiency expressed in $/ton. This approach is similar to the approach used by 

Georgia EPD to evaluate cost efficiency for other SIPS (e.g., ozone, PM2.5). 

Time Necessary For Compliance – General Considerations

GA EPD based the time necessary for compliance on the installation and operation of 

controls by the beginning of the year 2012. Since the next Regional Haze SIP will be 

due December 17, 2017, a compliance date of 2012 will result in visibility improvement 

for all five years of monitoring data (2012, 2013, 2014, 2015, and 2016) that will be 

assessed to determine conformity with 2018 progress goals at the time the next 

Regional Haze SIP is due. Any control options that can be installed and operated prior 

to 2012 were determined to be timely. Control options that cannot be installed and 

operated prior to 2012, but can be prior to 2018, would not result in the optimal amount 

of visibility improvement by the 2018 reasonable progress goal, but were still 

considered. Control options that could not be installed and operated until 2018 or after, 

were not considered for this Regional Haze SIP. 

Energy And Non-Air Quality Environmental Impacts Of Compliance – General 

Considerations

Additional factors that were considered were the energy requirements of the control 

technology and the non-air impacts (that is, impacts on other environmental media). 

Energy impacts were generally included in the cost-efficiency estimates. Non-air 

impacts that were considered included solid waste disposal, water withdrawal, and 

wastewater discharge. The review of control strategies that were not eliminated 

because of excessive cost efficiencies and that involved water withdrawal and 

wastewater discharge were coordinated with GA EPD’s Watershed Protection Branch. 
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Remaining Useful Life – General Considerations

The remaining useful life of an affected emissions unit can potentially impact 

reasonableness of control strategies in two ways. If the remaining useful life of an 

affected emission unit did not extend past 2018, no controls would be considered for 

that unit. If the remaining useful life of a unit was less than the amortization period for a 

particular control option, the shorter period was used in annualizing the capital costs of 

the control option when determining the cost efficiency. It should be noted that 

remaining useful life was not an issue for any of the control options reviewed by GA 

EPD. 

Results of Unit-Specific Analyses

As stated previously, GA EPD performed 4-factor analyses for 15 emissions units. The 

results are summarized below. For more details refer to Appendix H. 

Georgia Pacific, Brunswick Cellulose - Power Boiler U700 (F1) – This unit 

significantly contributes to the sulfate visibility impairment at two Class I areas 

(approximately 12.6% at Wolf Island and 3.9% at Okefenokee). This is the highest level 

of visibility impairment contribution to any Class I Area caused by any single emissions 

unit of those analyzed. The baseline SO2 emissions were 1642 tons-per-year. 

However, the boiler had already reduced emissions to approximately 1099 tons-peryear due to a 2002 modification achieving higher efficiency. 

The 4-factor analysis reviewed wet FGD, in-duct sorbent injection, and a limitation on 

fuel oil usage coupled with lower fuel oil sulfur content (2.2% and 1.0%). It should be 

noted that the fuel oil usage limitation proposed by the company is representative of 

their current usage rate. Of these control measures, the fuel oil changes could take 

place prior to 2012 and the wet FGD and in-duct sorbent injection could be installed 

before 2013. The remaining useful life of the unit extended past 2018 and the control 

equipment amortization period. The wet FGD had an impact on water usage and 

wastewater discharge and in-duct sorbent injection resulted in additional solid waste. 

There were no significant energy impacts addressed by the company. 

Out of all of the control options considered, both in-duct sorbent injection and a switch 

to 1.0% fuel oil coupled with a five-million-gallon-per-year usage limit were considered 

reasonably cost effective ($3562/ton and $20.7MM/Mm-1 at Wolf Island for in-duct 

sorbent injection and $3228/ton and $18.8MM/Mm-1 at Wolf Island for 1.0% fuel oil). 

These were considered cost effective due to the relatively high visibility impact on two 

Class I areas and the fact that neither of these Class I areas were clearly meeting the 

uniform rate of progress. Both in-duct sorbent injection and 1.0% sulfur fuel oil achieve 

approximately the same amount of emissions reductions (769 tpy for sorbent injection 

and 731 tpy for 1.0% sulfur) from the current level of 1099 tons/year. Implementation of 

the less restrictive of these two options would reduce SO2 emissions to 368 tons/12-

consecutive months (1099 tpy – 731 tpy). 
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Supplemental information provided by the facility indicated that the two controls deemed 

to be reasonable would control emissions from oil combustion but would not affect SO2 

emissions from combustion of wood waste and tire-derived fuel (TDF). The facility 

requested an allowance for an additional 200 tons of emissions based on calculations of 

historical emissions from wood waste and TDF. This request was also supported by the 

facility’s assertion that the sulfur content of locally available TDF may be above what 

has been burned historically. EPD concurred with the facility’s request and established 

an SO2 emissions limit for the power boiler of 568 tons (368 plus 200) for Regional 

Haze reasonable progress with a compliance date of 2012. 

Georgia Pacific, Brunswick Cellulose - Recovery Boiler R407 (M24) - This unit 

contributes about 1.3 % to the sulfate visibility impairment at Wolf Island. The baseline 

SO2 emissions were 193 tons/year. Georgia Pacific’s four-factor submittal found 

combustion control and wet FGD (scrubber) to be the only technically feasible control 

options. The company stated that emissions of SO2 of 38 ppm, as measured in a 2006 

stack test, is too low of a load for effective operation of a wet scrubber. Therefore, the 

company ruled out wet FGD based on cost effectiveness. 

Combustion control, the other technically feasible control option, is already included in 

the boiler design. Due to the fact that this emission unit only contributes to visibility 

impairment at one Class I area and the relatively low baseline emissions level, no 

additional controls are required for Regional Haze reasonable progress. 

Georgia Pacific, Cedar Springs, Power Boiler U500 (Power Boiler 1) and Power 

Boiler U501 (Power Boiler 2) – These are two nearly identical power boilers. Each of 

these units contribute about 1.1% to the sulfate visibility impairment at Saint Marks 

Class I area. The baseline SO2 emissions were 1976 tons/year for each boiler. 

The 4-factor analyses reviewed wet FGD, addition of spray towers and caustic to the 

existing venturi scrubbers, adding caustic to the existing scrubbers (79% SO2 

reduction), in-duct sorbent injection, coal washing, and coal switching. In addition to 

these control measures, Georgia Pacific submitted two control scenarios as part of their 

BART exemption modeling request (see section 7.7) that included the addition of lower 

amounts of caustic to their existing scrubbers (approximately 68% and 37% SO2 

reduction). All of the control options could be installed prior to 2012 except the wet FGD 

which could be installed before 2013. All three of the scrubber options (wet FGD, 

adding spray towers to the existing scrubbers, and adding caustic to the existing 

venturis) result in 15,000 tons/year of solid waste. There were no significant energy 

impacts addressed by the company. The remaining useful life of the unit extended past 

2018 and the control equipment amortization period. 

Out of all the control options considered, adding caustic to the existing venturi scrubber 

and in-duct sorbent injection were considered reasonably cost effective ($1675/ton and 
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$849.2MM/Mm-1 at Saint Marks for adding caustic to the scrubber and $1663/ton and 

$843. 2MM/Mm-1 at Saint Marks for in-duct sorbent injection). These were considered 

cost effective due to the relatively low visibility impact on only one Class I area 

(although St. Marks is not clearly meeting the uniform rate of progress.) Since the 

company submitted control options for three different levels of caustic use (79%, 68%, 

and 37% SO2 reduction), GA EPD analyzed the information to determine which level of 

caustic use was considered reasonable (in-duct sorbent injection achieves 

approximately 70% reduction, which is within the range of control efficiencies for caustic 

scrubbing). As part of Georgia Pacific’s BART exemption modeling, the company has 

proposed SO2 emission limits of 135 pounds each per hour from Power Boilers 1 and 2, 

along with additional limits of Recovery Boiler 3 (see section 7.7.2 for further discussion 

on these BART exemption limits). A limit of 135 lb/hr would result in maximum annual 

emissions of 591 tons/yr of SO2. This results in a 70% reduction. The actual annual 

reduction should be even higher since the boiler would not be expected to emit SO2 at 

the maximum allowable level for an entire year. Therefore, the 70+% reduction required 

by the BART exemption limit satisfies the requirement for reasonable progress. No 

additional limitations will be required. 

Georgia Pacific, Cedar Springs, Recovery Boiler R402 (Recovery Boiler 3) - This 

unit contributes about 0.8 % to the sulfate visibility impairment at Saint Marks class I 

area. The baseline SO2 emissions were 1726 tons/year. (Although, Georgia-Pacific 

submitted 2006 and 2007 SO2 emissions significantly lower than this baseline at 462 

and 741 tons/year, respectively. 

The 4-factor analyses reviewed switching from No. 6 fuel oil to No. 2 fuel oil (0.5 % 

sulfur), switching to 1% sulfur No. 6 fuel oil, and the installation of a new concentrator 

and new multi-level air system. The company did not provide any indications that any of 

the control options could not be installed prior to 2012. No negative energy impacts or 

non-air quality environmental impacts were addressed by the company. Remaining 

useful life of the units extended past 2018 and the control equipment amortization 

periods. 

Of all of the control options considered, none were considered reasonable, given the 

relatively low visibility impact on a single Class I area. Therefore no additional controls 

will be required for Regional Haze Reasonable Progress. 

Georgia Pacific, Savannah River, Mill Boilers B001, B002, and B003 (Nos. 3, 4, and 

5 Boilers) – These are three relatively similar boilers, with B002 and B003 being almost 

identical. The units significantly impact one class I area (approximately 1.1%, 0.9%, 

and 0.8% at Wolf Island for B001, B002, and B003, respectively). The baseline SO2 

emissions for the three boilers are 1659 tons/yr, 1195 tons/yr, and 1190 tons/yr. Note 

that all three of these are re-circulating fluidized bed boilers with limestone injection in 

the combustion chamber. B001 currently achieves approximately 87% SO2 removal 

and Boilers B002 and B003 achieve approximately 90% SO2 removal. 
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The 4-factor analyses reviewed wet FGD, circulating fluidized bed scrubber, switching 

from petroleum coke to 100% coal, increased limestone injection, and rotating opposed 

fire air. Out of all the proposed changes, only increased limestone injection could occur 

prior to 2012. All other control measures could not be installed until after 2012, 

although estimated control dates were not provided. Wet FGD controls would result in 

increased water use and wastewater discharges. No significant energy impacts were 

addressed by the company. Remaining useful life of the units extended past 2018 and 

the control equipment amortization periods. Increased limestone injection would result 

in increased solid waste generation. Georgia-Pacific conducted trial operations with 

increased limestone injection rates and found that SO2 removal could only be increased 

by an additional two percent (from 87% to 89% for B001 and from 90% to 92% for B002 

& B003). Revised cost estimates were also derived from the trial operations. 

Of all of the control options considered, none were considered reasonable, given the 

resulting control efficiencies and the relatively low visibility impact on a single Class I 

area. Therefore no additional controls will be required for Regional Haze Reasonable 

Progress. 

Georgia Power, Plant Kraft, Steam Generators 1, 2, and 3 – These are three coalfired steam generating units (i.e., boilers) rated at 50, 54, and 104 MW, respectively. 

Units 1 and 2 each impact Wolf Island Class I area by approximately 0.5%. Unit 3 was 

initially determined to impact three Class I areas (approximately 3.3% at Wolf Island, 

0.9% at Okefenokee, and 0.8% at Cape Romain). However, with the projected 

reduction in SO2 emissions by 2018, the impact on Okefenokee and Cape Romain 

should drop below the 0.5% threshold and the impact at Wolf Island should drop below 

2%. The 2018 baseline SO2 emissions for units 1 through 3 were initially estimated by 

VISTAS at 691 tpy, 704 tpy, and 4474 tpy, respectively. As part of the supporting 

documentation for the 4-factor analyses, Georgia Power provided projected heat input 

through 2018 for these units. Those projections indicate that SO2 emissions will be 632 

tpy, 889 tpy, and 2455 tpy, respectively. While the heat inputs provided by Georgia 

Power for units 1 and 2 are similar to the VISTAS 2018 projections, Georgia Power’s 

projection for Unit 3 represents a 45 percent reduction in heat input and SO2. This was 

explained by Georgia Power as the result of additional capacity coming on line 

somewhere else between 2010 and 2017. The reduction in heat input for Plant Kraft is 

expected to occur by around 2015. GA EPD has utilized these revised heat inputs in 

conducting the 4-factor analyses. 

GA EPD can verify the heat input reduction during development of the next Regional 

Haze SIP (due in 2017). 

The same control measures were analyzed for the four statutory factors for all three 

units: wet FGD, coal switching, and coal washing. Wet FGD could not be installed until 

2016 because of required control device installations scheduled up until 2015 in 

Georgia Power’s system. The company did not address the implementation time for the 
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other control options. All three control options would require additional energy usage. 

Wet FGD and coal washing would result in increased water usage and wastewater 

discharges as well as additional solid waste generation. The remaining useful life of the 

units extended past 2018 and the control equipment amortization periods. The costs of 

wet FGD and coal switching were relatively high ($3216 to $8161/ton and $56.9MM to 

$144.5MM/Mm-1 for wet FGD and $4041to $4306/ton and $71.5MM/Mm-1 for coal 

switching). Coal washing was relatively cost effective ($1839 to $1847/ton and $32.5 to 

$32.7/Mm-1) but the control efficiency is only 6%. Regarding non-air environmental 

impacts, the company indicated that coal switching could possibly reduce boiler 

efficiency, would use up to 7500 gallons (at Unit 3) per day of water, would result in 

acidic wastewater requiring treatment, and would result in coal refuse in the amount of 

approximately 5% of the total coal consumption. This control efficiency is projected to 

achieve low extinction reductions (which are visibility improvements) at Wolf Island. 

Based on the relatively low control efficiency of this option, the negative non-air 

environmental impacts, and the relatively low visibility impact, coal washing was 

determined not to be reasonable. Based on the above considerations, no additional 

controls will be required for any of the Plant Kraft units. 

Georgia Power, Plant McIntosh, Steam Generator 1 – This coal-fired steamgenerating unit (i.e., boiler) is rated at 178 MW. This unit was initially determined to 

impact five Class I areas (approximately 4.1% at Wolf Island, approximately 1.2% at 

Okefenokee, approximately 0.6% at Saint Marks, approximately 1.5% at Cape Romain, 

and approximately 0.7% at Swanquarter). However, with the projected reduction in 

SO2 emissions by 2018, the impact on all of these except Wolf Island should drop 

below the 0.5% threshold and the impact at Wolf Island should drop to close to 1%. 

The 2018 baseline SO2 emissions were initially estimated by VISTAS at 7015 tpy. As 

part of the supporting documentation for the 4-factor analyses, Georgia Power provided 

projected heat input through 2018 for this unit. Those projections indicate that SO2 

emissions will drop to 1860 tpy by 2018. Georgia Power’s projection represents a 73 

percent reduction in heat input and SO2. This was explained by Georgia Power as a 

result of additional capacity coming on line somewhere else between 2010 and 2017. 

The reduction in heat input for Plant McIntosh is to occur between around 2011 and 

2016. GA EPD has utilized this revised SO2 emission rate in conducting the 4-factor 

analyses. GA EPD can verify the heat input reduction during development of the next 

Regional Haze SIP (due in 2017). 

Georgia Power analyzed the following control measures: wet FGD, coal switching, and 

coal washing. Wet FGD could not be installed until 2016 because required control 

device installations scheduled up until 2015 in Georgia Power’s system. The company 

did not address the implementation time for the other control options. All three control 

options would require additional energy usage. Wet FGD and coal washing would 

result in increased water usage and wastewater discharges as well as additional solid 

waste generation. The remaining useful life of the units extended past 2018 and the 

control equipment amortization periods. The cost effectiveness of all the control 

operations were relatively high ($7131/ton and $118.5MM/Mm-1 for wet FGD, $4306/ton 
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and $71.5MM/Mm-1 for coal switching, and $5334/ton and $91.9MM/Mm-1 for coal 

washing). Based on these factors, no additional controls will be required Plant 

McIntosh. 

Georgia Power, Plant Mitchell, Steam Generator 3 – This coal-fired steam-generating 

unit (i.e., boiler) is rated at 163 MW. (Note that this is the only remaining operational 

boiler at Plant Mitchell.) This unit was initially determined to impact two Class I areas 

(approximately 0.8% at Okefenokee and approximately 2.7% at Saint Marks). 

However, with the projected reduction in SO2 emissions by 2018, the impact on 

Okefenokee should drop below the 0.5% threshold and the impact on Saint Marks 

should drop to below 1%. The 2018 baseline SO2 emissions were initially estimated by 

VISTAS at 4930 tpy. As part of the supporting documentation for the 4-factor analyses, 

Georgia Power provided projected heat input through 2018 for this unit. Those 

projections indicate that SO2 emissions will drop to 1189 tpy by 2018. Georgia Power’s 

projection represents a 76 percent reduction in heat input and SO2. This was explained 

by Georgia Power as a result of additional capacity coming online somewhere else 

starting in 2010. The reduction in heat input for Plant Mitchell is to occur between 

around 2008 and 2010. GA EPD has utilized this revised SO2 emission rate in 

conducting the 4-factor analyses. GA EPD can verify the heat input reduction during 

the Regional Haze mid-course review in 2012. 

Georgia Power analyzed the following control measures: wet FGD and coal switching. 

Wet FGD could not be installed until 2016 because required control device installations 

scheduled up until 2015 in Georgia Power’s system. The company did not address the 

implementation time for coal switching. Both control options would require additional 

energy usage. Georgia Power did not indicate any additional water use, wastewater 

discharge, or solid waste generation issues for any of the control options. The 

remaining useful life of the units extended past 2018 and the control equipment 

amortization periods. The cost effectiveness for wet FGD was high ($9119/ton and 

$148.5MM/Mm-1). The cost effectiveness for coal switching was more reasonable 

($2347/ton and $38.2MM/Mm-1), but the control efficiency was relatively low at 43%. 

Based on these factors, including the projected significant utilization drop within the next 

few years, no additional controls will be required for Plant Mitchell. 

International Paper, Savannah, Power Boiler 13 – This is a 1280 MMBtu/hr coal, oil, 

and woodwaste fired boiler. It also combusts both low-volume high-concentration 

(LVHC) and high-volume low-concentration (HVLC) non-condensable gases from the 

pulping process and stripper off-gas (SOG) from the stripper used to control HAP 

emissions from wastewater streams. Baseline emissions are 8578 tons/year with 

approximately 1944 tons/yr of this coming from the combustion of LVHC, HVLC, and 

SOG. This unit significantly contributes to the sulfate visibility impairment at five Class I 

areas (approximately 6.4% at Wolf Island, approximately 1.7% at Okefenokee, 

approximately 0.7% at Saint Marks, approximately 1.6% at Cape Romain, and 

approximately 0.9% at Swanquarter). This is the highest number of Class I areas 

significantly impacted by any single emissions unit of all those reviewed. 
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The 4-factor analysis reviewed wet FGD (packed tower), FGD (wet limestone spray 

tower), semi-dry lime spray tower, fuel switching to natural gas, dry sorbent injections, 

and a stand-alone RTO with SO2 scrubbing for the control of LVHC, HVLC, and SOG 

(this control option was presented as three different combinations of LVHC, HVLC, and 

SOG combustion). Also, International Paper (IP) later suggested an SO2 reduction of 

2000 tons/year as a control option that would provide maximum flexibility for 

compliance. Except for the 2000 ton/year reduction alternative, all of these control 

options could be implemented by 2012. International Paper requested a 2016 

compliance date for the 2000 ton/yr reduction alternative. This compliance date is 

necessary in order for the company to take into consideration any reductions that will 

occur as a result of the Boiler MACT and the uncertainty surrounding that standard. 

The remaining useful life of the unit extended past 2018 and the control equipment 

amortization period. The wet FGD and all three RTO options had an impact on water 

usage and wastewater discharge. GA EPD Air Branch checked with GA EPD 

Watershed Protection Branch (WPB) personnel to discuss the potential water usage 

and wastewater discharges associated with these controls. WPB associates indicated 

that they would not be a problem as long as there was not additional BOD load on the 

Savannah River. Based on the type of chemicals that would be associated with effluent 

from a wet FGD, WPB associates stated that the controls should not result in additional 

BOD load. However, because of the current problem with dissolved oxygen in the 

Savannah River (there are strict limitations and perhaps a moratorium on any additional 

DO load to the river), any projects that could possibly increase DP load were not 

considered reasonable at this time. FGD (wet limestone spray tower, semi-dry lime 

spray tower, and dry sorbent injection) resulted in additional solid waste generation. 

There were energy impacts associated with all but the fuel switching options. These 

energy costs were factored into the overall control cost efficiency. 

Regarding the company’s cost efficiency estimates, EPD’s review indicated that the cost 

estimates for a packed tower wet FGD and wet limestone spray tower were higher than 

expected based on a number of metrics (cost per ACFM is about four times higher than 

other units of comparable size, company’s estimate is three to eight times higher than 

EPA cost estimation software, and International Paper used an admittedly conservative 

retrofit factor) plus the company used a cost estimation model not recommended by 

EPA. In a letter to IP on 12/21/2007, GA EPD requested site-specific cost analyses for 

these control options. In that letter, GA EPD stated that if site-specific estimates were 

not provided, that control option recommendations would be made with the 

understanding that the cost estimates may be overstated. In response, International 

Paper chose not to provide site-specific cost estimates as requested. However, despite 

the possibly high cost effectiveness numbers the FGD - wet limestone spray tower 

($4391/ton) was determined not to be cost effective. Wet FGD – packed tower, was not 

considered reasonable because of the possible impact on DO load to the Savannah 

River. Fuel switching to natural gas ($9506/ton), and dry sorbent injection ($5223/ton) 

were determined not to be reasonable because of cost effective. 
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The next most effective control option is a 6758 tons per year emission limit. However, 

since the option was proposed by the company, it had to be considered cost-effective. 

No specific emission reduction methodologies were associated with this control option, 

however, there are certain control methodologies that are under consideration (see 

Appendix H for details). The 6758 ton per year limit was determined by reducing the 

projected 2018 SO2 emissions baseline of 8758 tons per year by 2000 tons. EPD 

reviewed recent SO2 emissions data and determined that the 8758 tons per year 

baseline is a reasonable and not over-inflated baseline. A compliance date of 2016 was 

proposed in order to take into consideration any controls that will be required under the 

Boiler MACT currently under development. The Boiler MACT has been vacated and 

remanded to EPA, and EPA is developing a proposed boiler MACT rule. A 2016 

compliance date should provide sufficient time for the MACT to be proposed and 

promulgated, provide the three years required for compliance with the standard, and 

provide time to determine an appropriate method for complying with the 6758 SO2 

emissions limit from Power Boiler 13 following compliance with the MACT standard. 

Out of all of the control options considered, a 2000 tons per year reduction alternative 

was considered reasonably cost effective. This results in an emission limit of 6758 tons 

per year. The baseline SO2 emissions are 8578 tons/yr. A review of past CERR 

reports SO2 emissions from PB13 at 7620 to 7699 tpy from 2002-2005 and increasing 

to 8974 tpy in 2006. The increase in 2006 may be due to the compliance date for phase 

II of the “Cluster Rule” MACT standard that required collection and treatment of 

emissions from pulp mill condensate beginning in 2006. This would have resulted in 

increased sulfur emission from SOG which were then combusted in PB13 to form SO2. 

Therefore, the 8578 ton/year estimate is a good baseline for determining allowable 

emissions based on a selected control technology. A 2000 tons per year reduction 

results in an emission limit of 6578 tons/year. This limit will include SO2 emissions 

resulting from the combustion of LVHC, HVLC, and SOG, whether they are combusted 

in Power Boiler 13 or some other combustion device. In order to provide flexibility for 

the facility, an emission limit of 6578 tons/12-consecutive months will be required for 

Power Boiler 13 as a requirement of Regional Haze reasonable progress with a 

compliance date of 2016. 

Temple-Inland Rome Linerboard, No. 4 Power Boiler - This is a 565 MMBtu/hr coal 

and oil fired boiler. This unit significantly contributes to the sulfate visibility impairment 

at two Class I areas (approximately 4.4% at Cohutta and approximately 1.0% at Joyce 

Kilmer/Slickrock). 
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The 4-factor analysis reviewed two wet FGD configurations [magnesium enhanced lime 

(MEL) and limestone forced oxidation (LSFO)], dry FGD (lime absorbent), fuel 

switching, and dry sorbent injection. All of these control options could be implemented 

by 2012. The remaining useful life of the unit extended past 2018 and the control 

equipment amortization period. The wet FGD options had an impact on water usage. 

GA EPD Air Branch checked with GA EPD Watershed Protection Branch personnel to 

discuss the potential water usage and was informed that the mill had sufficient capacity 

within their currently permitted water withdrawal permit to easily handle the increased 

water use associated with wet FGD. All of the control options resulted in additional solid 

waste generation. There were energy impacts associated with all of the control options. 

These energy costs were factored into the overall control cost efficiency. None of the 

control options considered had a cost effectiveness that was determined reasonable at 

this time. Of all of the control options considered, none were considered reasonable at 

this time. The fact that the affected Class I areas impacted by this unit are predicted to 

meet the Uniform Rate of Progress in 2018 with controls that are already on the books 

was a key factor in determining what was considered “reasonable” for reasonable 

progress requirements for this source. This determination may be revisited at the midcourse review or when determining future Regional Haze reasonable progress goals 

(i.e., future Regional Haze SIPs). 

7.6.4 Required Controls for Sources Subject to Four-Factor Analysis in Georgia

Table 7.6.4-1 provides a summary of the required emission limits for the sources 

subject to 4-factor analysis in Georgia. The final determinations were based on the 4-

factor analyses and reviews and are detailed in Appendix H. GA EPD decided on limits 

that would be consistent with controls that were reasonably cost effective. Reasonable 

costs were based on the number of Class I areas impacted, the magnitude of visibility 

impact on Class I area, progress of the impacted Class I area relative to the glide slope, 

and cost effectiveness. Once the control or controls were determined to be reasonable, 

an emission limit was applied based on the expected emission reduction from the 

control technology or technologies to allow the facility flexibility in meeting the limit. The 

control technology was not required. This approach was determined to be an effective 

means of obtaining reasonable emission reductions. 

Note that this table presents four-factor data only for controls that were deemed to be 

reasonable and cost-effective. Table 6.1 of Appendix H includes four-factor data on 

control options that were deemed not cost-effective. 

The required emission limits will be implemented by adding them as permit conditions 

(see Appendix M) to the Title V operating permits of the affected facilities. 

Recordkeeping, monitoring, and testing requirements will be included to demonstrate 

compliance with the limits. These requirements will be consistent with Georgia EPD’s 

Procedures for Testing and Monitoring Sources of Air Pollutants (PTM) and must meet 
Georgia Regional Haze State Implementation Plan 

92 of 124 

the requirements of Compliance Assurance Monitoring (40 CFR Part 64) or Periodic 

Monitoring [40 CFR 70.6(3)(i)(B)], as appropriate. 
Georgia Regional Haze State Implementation Plan 

Table 7.6.4-1. Summary of Required Emissions Limits for Sources Subject to Four-Facto

Facility Emissions 

unit 

2018 SO2 

emissions 

estimate, 

uncontrolled 

(tpy)1

% of sulfate 

visibility 

impact at 

Class I area

Reasonable 

costeffective 

control 

options2,4

Annual 

cost 

($/ton)1,4

Cost/visibility 

at nearest 

Class I 

($106/Mm-1)

4

Life of 

unit 

Non-air 

environmental 

impacts4

Re

(

con

m

1642 Oil limit and 

in-duct sorbent 

injection 

3562 20.7 8000 tons/yr of 

solid waste 

Power Boiler 

No. 4 (F1) 

10993

12.55 WOLF 

3.89 OKEF 

Oil limit and 

fuel switch to S 

= 1.0% 

3228 18.8 

Beyond 

2018 

None 

GA Pacific 

Brunswick 

Cellulose 

Recovery 

Boiler No. 6 

(M24) 

193 VISTAS 1.31 WOLF No costeffective 

controls 

No costeffective 

controls

No costeffective 

controls 

Beyond 

2018 

No cost-effective 

controls 

No

Add caustic to 

existing venturi 

scrubber 

Power Boiler 1675 849.2 

U500 

1976 1.08 SAMA 

In-Duct 

sorbent 

injection 

1663 843.2 

Beyond 

2018 

15000 tons/yr of 

solid waste 

ex

m

lim

Add caustic to 

existing venturi 

scrubber 

Power Boiler 1675 849.2 

U501 

1976 1.13 SAMA 

In-Duct 

sorbent 

injection 

1663 843.2 

Beyond 

2018 

Not Provided 

ex

m

lim

GA Pacific 

Cedar 

Springs 

Recovery 

Boiler R402 

1726 VISTAS 0.77 SAMA No costeffective 

controls 

No costeffective 

controls

No costeffective 

controls 

Beyond 

2018 

No cost-effective 

controls 

No
Georgia Regional Haze State Implementation Plan 

Table 7.6.4-1. Summary of Four-Factor Analyses (continued)

Facility Emissions 

unit 

2018 SO2 

emissions 

estimate, 

uncontrolled 

(tpy)1

% of sulfate 

visibility 

impact at 

Class I area

Reasonable 

costeffective 

control 

options2,4

Annual 

cost 

($/ton)1,4

Cost/visibility at 

nearest Class I 

($106/Mm-1)

4

Life of 

unit

Non-ai

environme

impact

Boiler B001 1659 1.11 WOLF No costeffective 

controls 

No cost-effective 

controls 

Beyond 

2018 

No cost-effe

control

Boiler B002 1195 0.86 WOLF No costeffective 

controls 

No cost-effective 

controls 

Beyond 

2018 

No cost-effe

control

GA Pacific – 

Savannah R. 

Mill 

Boiler B003 1190 0.77 WOLF

No costeffective 

controls 

No costeffective 

controls 

No cost-effective 

controls 

Beyond 

2018 

No cost-effe

control

Steam 

Generator 

SG01 

632 0.51 WOLF No costeffective 

controls 

No cost-effective 

controls 

Beyond 

2018 

No cost-effe

control

GA Power 

Company Plant 

Kraft 

Steam 

Generator 

SG02 

889 0.52 WOLF 

No costeffective 

controls. 

Facility 

forecasts 

capacity 

utilization 

drops, around 

2015, to 23%, 

34%, and 50% 

(SG01, SG02, 

SG03). 

No costeffective 

controls 

No cost-effective 

controls 

Beyond 

2018 

No cost-effe

control
Georgia Regional Haze State Implementation Plan 

Facility Emissions 

unit 

2018 SO2 

emissions 

estimate, 

uncontrolled 

(tpy)1

% of sulfate 

visibility 

impact at 

Class I area

Reasonable 

costeffective 

control 

options2,4

Annual 

cost 

($/ton)1,4

Cost/visibility at 

nearest Class I 

($106/Mm-1)

4

Life of 

unit

env

i

GA Power 

Company Plant 

Kraft 

Steam 

Generator 

SG03 

2455 3.30 WOLF 

0.85 OKEF 

0.81 ROMA 

No costeffective 

controls. 

Facility 

forecasts 

capacity 

utilization 

drops, around 

2015, to 23%, 

34%, and 50% 

(SG01, SG02, 

SG03 

No costeffective 

controls

No cost-effective 

controls 

Beyond 

2018 

No c

GA Power 

Company Plant 

Mitchell 

Steam 

Generator 

SG03 

1189 2.74 SAMA 

0.77 OKEF 

No additional 

controls are 

required since 

the facility 

forecasts a 

capacity 

utilization 

drop to 11 % 

by 2018 

No costeffective 

controls

No cost-effective 

controls 

Beyond 

2018 

No c

GA Power 

Company Plant 

McIntosh 

Steam 

Generator 

SG01 

1860 4.13 WOLF 

1.20 OKEF 0.55 SAMA 1.35 ROMA 0.72 SWAN 

No additional 

controls are 

required since 

the facility 

forecasts a 

capacity 

utilization 

drop to 24 % 

by 2018 

No costeffective 

controls

No cost-effective 

controls 

Beyond 

2018 

No c

Facility Emissions 

unit 

2018 SO2 

emissions 

estimate, 

uncontrolled 

% of sulfate visibility impact at Class I area

Reasonable 

costeffective 

control 

Annual 

cost 

($/ton)1,4

Cost/visibility at 

nearest Class I 

($106/Mm-1)

4

Life of 

unit

env

i
Georgia Regional Haze State Implementation Plan 

(tpy)1 options2,4 

International Paper 

– Savannah Mill 

Power Boiler 

PB 13 

8578 6.64 WOLF 

1.66 OKEF 0.70 SAMA 1.55 ROMA 0.86 SWAN 

6578 tons per 

year emission 

limit5

Not 

provided5

Not provided5 Beyond 

2018 

No

Temple-Inland 

Rome Linerboard 

Power Boiler 

F4 

3837 4.42 COHU 

0.99 JOKI 

No additional 

controls were 

cost effective

No costeffective 

controls

No cost-effective 

controls 

Beyond 

2018 

Redu

gene

cons

gyps

(1) from facility-provided data, unless indicated otherwise (2) in the case of multiple options, each option would provide approximately the same level of SO2 reductions 

(3) revised estimate, based on 2002 modification to boiler to increase efficiency; lowered typical oil usage to 5 million gal/yr or less 

(4) See Appendix H, Table 6.1, for four-factor data on control options that were deemed not cost-effective. 

(5) Control options evaluated for International Paper PB 13 are documented in Appendix H. Several options are capable of 

achieving a reduction to 6578 tons/year. 

Class I Areas: WOLF Wolf Is. SWAN Swan Quarter OKEF Okefenokee COHU Cohutta SAMA St. Marks JOKI Joyce Kilmer ROMA Romain 
Georgia Regional Haze State Implementation Plan 

97 of 124 

Three facilities, due to resource limitations and/or uncertainty regarding future 

operations, requested limits on their affected emissions units in lieu of performing fourfactor analyses: Rayonier Performance Fibers, Packaging Corporation of America, and 

Southern States Phosphate and Fertilizer. The required limits dropped the sulfate 

contributions of these units below 0.5 percent of the total sulfate impact on any affected 

Class I areas. 

 

Table 7.6.4-2 lists the limits and compliance dates for the four-factor and the four-factor 

exempted units. In addition the estimated tons reduced with the new limits are 

presented. Limits for the four-factor units are on actual emissions as currently stated, 

but this could change if additional conditions are added during the permit amendment 

process. The limits for the four-factor exempted units are based on actual (rather than 

potential) emissions, as the permit conditions do not depend solely on fuel sulfur 

content or on equipment capacities. Note that the permit limits for PB02, RF01, and 

RF04 at Rayonier Performance Fibers are on fuel usage and on stack SO2 

concentrations (RF01 and RF04 only) that have been calculated to achieve the ton-peryear limits shown in the table. The limit on RF01 becomes effective upon the 

completion of the Plant’s Phase 1 projects, which include the addition of SO2 control 

(staged air combustion). The limit on RF04 becomes effective upon the completion of 

the Plant’s Phase 2 projects, which include the addition of SO2 control (staged air 

combustion). The permitting of Phases 1 and 2 allows for increased production and 

burning of black liquor solids, but only after the emissions controls are installed. At the 

time of this SIP submittal, the projects were suspended due to depressed market 

conditions in 2009. 

Figure 7.6.4-1 shows the locations of facilities with emission units eligible for 4-factor 

analysis. In addition, the basis for reductions (control or exemption) is indicated for 

those facilities at which reductions are required.
Georgia Regional Haze State Implementation Plan 

98 of 124 

Table 7.6.4-2. Permit Limits for Implementation of Reasonable Progress 

Emissions Reductions 

Facility Emissions 

Unit 

Permit limit 

(tpy of SO2, except as noted)

Estimated 

Tons 

Reduced 

GA Pacific – 

Brunswick 

Cellulose 

F1 

Pwr. Boiler 4 

Not more than 568 tons SO2 per 12 

consecutive months, compliance 

date of January 1, 20121

1074 

Power Boiler 

U500 

135 pound SO2 per hour (same as 

BART exemption modeling limit) 

Georgia Pacific – 1385 

Cedar Springs 

Power Boiler 

U501 

135 pound SO2 per hour (same as 

BART exemption modeling limit) 

1385 

International 

Paper – Savannah 

Pwr. Boiler 

13, including 

combustion 

of process 

organic 

emissions 

Not more than 6758 tons SO2 per 

12 consecutive months, compliance 

date of January 1, 20162

2000 

Packaging Corp. 

of America3 

CE Power 

Boiler 

Not more than 600 tons SO2 per 12 

consecutive months, compliance 

date of January 1, 20121

53 

PB02 

Pwr. Boiler 2 

Not more than 318 tons SO2 per 12 

consecutive months, compliance 

date of June 4, 20084

306 

PB03 

Pwr. Boiler 3 

Not more than 149 tons SO2 per 12 

consecutive months, compliance 

date of June 4, 20084

1448 

RF01 

No. 5 Rec. 

Furn. 

Not more than 194 tons SO2 per 12 

consecutive months, compliance 

date tied to facility modification5

139 

Rayonier Perf. 

Fibers3

RF04 

No. 6 Rec. 

Furn. 

Not more than 307 tons SO2 per 12 

consecutive months, compliance 

date tied to facility modification5

27 

Southern States 

Phosphate and 

Fertilizer3

SA02 

Acid Plant 2 

Not more than 580 tons SO2 per 12 

consecutive months, compliance 

date of January 1, 20146

228 

(1) start of record-keeping; first 12 months will be January 1 – December 31, 2012 

(2) start of record-keeping; first 12 months will be January 1 – December 31, 2016 

(3) These facilities took limits on the respective units in order to be exempt from submitting fourfactor analyses 

(4) start of record-keeping; first 12 months will be June 4, 2008, through June 3, 2009 

(5) The actual limits on RF01 and RF04 are stack concentrations of 15 ppm or less SO2 and 19 

ppm or less SO2, respectively. The limit on RF01 becomes effective upon the completion of the 

Plant’s Phase 1 projects, which include the addition of SO2 control (staged air combustion). The 

limit on RF04 becomes effective upon the completion of the Plant’s Phase 2 projects, which 

include the addition of SO2 control (staged air combustion). 

(6) start of record-keeping; first 12 months will be January 1 – December 31, 2014 
Georgia Regional Haze State Implementation Plan 

99 of 124 

Figure 7.6.4-1. Locations Of Facilities With Emission Units Eligible 

For Four-Factor Analysis 
Georgia Regional Haze State Implementation Plan 

100 of 124 

7.7 Control Determinations Representing Best Available Retrofit Technology 

(BART) for Individual Sources 

Section 169A of the CAA directs States to assess certain large, older emission sources 

for additional controls in order to address visibility impacts. States are directed to 

conduct BART determinations for such sources in specific source categories and which 

contribute to visibility impairment in Class I areas. The 1999 regional haze rule includes 

the BART requirement, and directs States to include BART in their regional haze SIPs. 

On July 6, 2005, US EPA published a revised final rule, including Appendix Y to 40 CFR 

Part 51, the Guidelines for BART Determinations Under the Regional Haze Rule (the 

“BART Guidelines”) that provides direction to states on determining which of these 

sources should be subject to BART, and how to determine BART for each source. 

A BART-eligible source is one which has the potential to emit 250 tons or more of a 

visibility-impairing air pollutant, one which was put in place between August 7, 1962, 

and August 7, 1977, and one whose operations fall within one or more of 26 specifically 

listed source categories. Under the CAA, BART is required for any BART-eligible 

source that a State determines ‘‘emits any air pollutant which may reasonably be 

anticipated to cause or contribute to any impairment of visibility in any such area.’’ 

For those sources subject to BART, Section 169A(g)(7) of the CAA requires that States 

must consider the following factors in making BART determinations: (1) the costs of 

compliance, (2) the energy and non-air quality environmental impacts of compliance, (3) 

any existing pollution control technology in use at the source, (4) the remaining useful 

life of the source, and (5) the degree of improvement in visibility which may reasonably 

be anticipated to result from the use of such technology. 
Georgia Regional Haze State Implementation Plan 

101 of 124 

7.7.1 BART-Eligible Sources in Georgia 

 Table 7.7.1-1. Facilities with BART-eligible sources in Georgia 

BART –Eligible Sources 

Chemical Products Corporation 

DSM Chemicals, North America 

Georgia Pacific – Cedar Springs 

Georgia Power – Plant Bowen 

Georgia Power Plant Branch 

Georgia Power – Plant Hammond 

Georgia Power – Plant McDonough 

Georgia Power – Plant Mitchell 

Georgia Power – Plant Scherer 

Georgia Power – Wansley 

Georgia Power – Yates 

International Paper – Augusta 

International Paper – Savannah 

Interstate Paper, LLC 

Koch Cellulose (Georgia Pacific – Brunswick / Brunswick Pulp & Paper) 

Lafarge Building Materials (Blue Circle Cement – Atlanta Plant) 

Owens Corning 

PCA –Valdosta (Tenneco Packaging, Inc.) 

PCS Nitrogen 

Prayon, Inc. 

Rayonier (Rayonier ITT, Inc.) 

Savannah Electric – Plant Kraft 

Savannah Electric – Plant McIntosh 

Tronox (Kerr – McGee / Kemira)

 

BART-eligible sources were identified using the methodology in the BART Guidelines: 
Georgia Regional Haze State Implementation Plan 

102 of 124 

• One or more emissions units at the facility fit within one of the 26 categories 

listed in the BART Guidelines; 

• The emission unit(s) were in existence on August 7, 1977, and began operation 

at some point on or after August 7, 1962; and 

• The limited potential emissions from all emission units identified in the previous 

two bullets emission units were greater than 250 tons or more per year of any of 

these visibility-impairing pollutants: SO2, NOx, and PM10.

The BART Guidelines recommend addressing these visibility-impairing pollutants: SO2, 

NOx, and particulate matter, and suggest that States use their best judgment in 

determining whether to address VOC or ammonia emissions. GA EPD addressed SO2 

and NOx, and used particulate matter less than 10 microns in diameter (PM10) as an 

indicator for particulate matter to identify BART-eligible units, as the BART guidelines 

recommend. As discussed in detail in Appendix H, VISTAS modeling demonstrated 

that VOCs and ammonia from point sources are not visibility-impairing pollutants. For 

this reason GA EPD did not evaluate emissions of VOCs and ammonia in BART 

determinations. 

7.7.2 Determination of Sources Subject to BART in Georgia 

Under the BART Guidelines, GA EPD may consider exempting some sources from 

BART if we find that they do not cause or contribute to visibility impairment in a Class I 

area. In accordance with the BART guidelines, GA EPD chose to perform sourcespecific analyses to determine which sources cause or contribute to visibility impairment 

using the CALPUFF model. The CALPUFF modeling protocol used for determining 

which facilities are subject to BART is included in Appendix H.7. In accordance with the 

Guidelines, a contribution threshold of 0.5 deciviews was used for determining which 

sources were subject to BART. 

All of Georgia’s BART-eligible sources submitted exemption modeling demonstrations. 

Twenty-two of the twenty-four sources were able to demonstrate exemption. Additional 

details including BART modeling protocols and exemption reports submitted by the 

facilities are available in Appendix H. Supporting files and databases that would be 

impracticable to print are available electronically, both on the submitted CD-R and via 

permanent EPD web links. In addition, files are permanently archived on EPD 

computer networks. To request access to any of these files please contact the Georgia 

EPD Air Protection Branch at (404) 363-7000. Facilities found to be subject to BART 

must complete a BART analysis. 

Table 7.7.2-1 represents the facilities that were able to demonstrate exemption from 

BART based on CALPUFF modeling conducted using the VISTAS modeling protocol. 

All the listed facilities used old IMPROVE equation except Georgia Pacific Cedar 

Springs which used new IMPROVE equation to demonstrate its exemption from BART 
Georgia Regional Haze State Implementation Plan 

103 of 124 

Table 7.7.2-1 Exemption modeling results for BART-eligible sources. 

Facility Class 1 Areas Impacted Grid 

Resolution 

DeltaDeciviews

Cohutta Wilderness Area 4 km 0.442 

Great Smoky Mountains National Par 4 km 0.173 

Joyce-Kilmer Wilderness Area 4 km 0.197 

Sipsey Wilderness Area 4 km 0.127 

Chemical 

Products 

Corporation 

Shining Rock Wilderness Area 4 km 0.090 

Cape Romain Wilderness Area 12 km 0.094 

Cohutta Wilderness Area 12 km 0.112 

Great Smoky Mountains National 

Park 

12 km 0.072 

Joyce-Kilmer Wilderness Area 12 km 0.036 

Okefenokee Wilderness Area 12 km 0.063 

Shining Rock Wilderness Area 12 km 0.069 

DSM Chemicals, 

North America 

Wolf Island Wilderness Area 12 km 0.114 

Georgia Pacific – Okefenokee Wilderness Area 4 km 0.306 

Cedar Springs* St. Marks Wilderness Area 4 km 0.499 

Cohutta Wilderness Area 4 km 0.17 

Great Smoky Mountains National 

Park 

4 km 0.11 

Joyce-Kilmer Wilderness Area 4 km 0.09 

Okefenokee Wilderness Area 4 km 0.12 

Shining Rock Wilderness Area 4 km 0.09 

Georgia Power – 

Plant Branch 

Wolf Island Wilderness Area 4 km 0.11 

Cohutta Wilderness Area 4 km 0.29 

Great Smoky Mountains National 

Park 

4 km 0.08 

Joyce-Kilmer Wilderness Area 4 km 0.09 

Shining Rock Wilderness Area 4 km 0.05 

Georgia Power – 

Plant Hammond 

Sipsey Wilderness Area 4 km 0.06 

Cohutta Wilderness Area 4 km 0.19 

Great Smoky Mountains National 

Park 

4 km 0.07 

Joyce-Kilmer Wilderness Area 4 km 0.07 

Shining Rock Wilderness Area 4 km 0.05 

Georgia Power – 

Plant McDonough 

Sipsey Wilderness Area 4 km 0.04 

Okefenokee Wilderness Area 4 km 0.04 

St. Marks Wilderness Area 4 km 0.05 

Georgia Power – 

Plant Mitchell 

Wolf Island Wilderness Area 4 km 0.02 
Georgia Regional Haze State Implementation Plan 

104 of 124 

Cohutta Wilderness Area 4 km 0.08 

Great Smoky Mountains National 

Park 

4 km 0.07 

Joyce-Kilmer Wilderness Area 4 km 0.07 

Okefenokee Wilderness Area 4 km 0.08 

Shining Rock Wilderness Area 4 km 0.06 

Georgia Power – 

Plant Scherer 

Wolf Island Wilderness Area 4 km 0.05 

Georgia Power – 

Plant Wansley 

Cohutta Wilderness Area 4 km 0.44 

Great Smoky Mountains National Par 4 km 0.17 

Joyce-Kilmer Wilderness Area 4 km 0.18 

Sipsey Wilderness Area 4 km 0.14 

Georgia Power – 

Plant Wansley 

Shining Rock Wilderness Area 4 km 0.12 

Cohutta Wilderness Area 4 km 0.15 

Great Smoky Mountains National Par 4 km 0.05 

Joyce-Kilmer Wilderness Area 4 km 0.06 

Sipsey Wilderness Area 4 km 0.05 

Georgia Power – 

Plant Yates 

Shining Rock Wilderness Area 4 km 0.03 

Cape Romain Wilderness Area 4 km 0.211 

Cohutta Wilderness Area 4 km 0.114 

Great Smoky Mountains National 

Park 

4 km 0.093 

Joyce-Kilmer Wilderness Area 4 km 0.086 

Linville Gorge Wilderness Area 4 km 0.103 

Okefenokee Wilderness Area 4 km 0.157 

Shining Rock Wilderness Area 4 km 0.127 

International 

Paper – Augusta 

Wolf Island Wilderness Area 4 km 0.148 

Cape Romain Wilderness Area 4 km 0.092 

Okefenokee Wilderness Area 4 km 0.282 

St. Marks Wilderness Area 4 km 0.055 

Koch Cellulose 

(GP – Brunswick, 

Brunswick Pulp 

and Paper Wolf Island Wilderness Area 4 km 0.447 

Cohutta Wilderness Area 12 km 0.119 

Great Smoky Mountains National Par 12 km 0.051 

Joyce-Kilmer Wilderness Area 12 km 0.056 

Sipsey Wilderness Area 12 km 0.054 

Owens Corning 

Shining Rock Wilderness Area 12 km 0.072 

Chassahowitzka Wilderness Area 12 km 0.197 

Okefenokee Wilderness Area 12 km 0.349 

St. Marks Wilderness Area 4 km 0.190 

PCA- Valdosta 

Wolf Island Wilderness Area 12 km 0.181 
Georgia Regional Haze State Implementation Plan 

105 of 124 

Cape Romain Wilderness Area 4 km 0.359 

Cohutta Wilderness Area 12 km 0.409 

Great Smoky Mountains National 

Park 

12 km 0.163 

Joyce-Kilmer Wilderness Area 12 km 0.175 

Linville Gorge Wilderness Area 12 km 0.393 

Okefenokee Wilderness Area 12 km 0.393 

Shining Rock Wilderness Area 12 km 0.220 

PCS Nitrogen 

Wolf Island Wilderness Area 12 km 0.294 

Cape Romain Wilderness Area 12 km 0.009 

Cohutta Wilderness Area 12 km 0.004 

Great Smoky Mountains National 

Park 

12 km 0.002 

Joyce-Kilmer Wilderness Area 12 km 0.002 

Linville Gorge Wilderness Area 12 km 0.005 

Okefenokee Wilderness Area 12 km 0.007 

Shining Rock Wilderness Area 12 km 0.003 

Prayon, Inc. 

Wolf Island Wilderness Area 12 km 0.005 

Cape Romain Wilderness Area 12 km 0.132 

Okefenokee Wilderness Area 12 km 0.254 

St. Marks Wilderness Area 12 km 0.151 

Rayonier 

Wolf Island Wilderness Area 12 km 0.319 

Cape Romain Wilderness Area 4 km 0.18 

Okefenokee Wilderness Area 4 km 0.18 

Savannah Electric 

– Plant Kraft 

Wolf Island Wilderness Area 4 km 0.21 

Cape Romain Wilderness Area 4 km 0.04 

Okefenokee Wilderness Area 4 km 0.03 

Savannah Electric 

– Plant McIntosh 

Wolf Island Wilderness Area 4 km 0.03 

Cape Romain Wilderness Area 12 km 0.134 

Okefenokee Wilderness Area 12 km 0.213 

Tronox (KerrMcGee/Kemira) 

Wolf Island Wilderness Area 12 km 0.246 

* Note: All sources used the old IMPROVE equation except Georgia Pacific – Cedar 

Springs, which used the new IMPROVE equation.

Table 7.7.2-2 represents the facilities that were able to demonstrate exemption from 

BART based on model plant criteria or by accepting emissions limits for visibility 

causing pollutants. 
Georgia Regional Haze State Implementation Plan 

106 of 124 

Table 7.7.2-2. Facilities exempted from BART via other methods 

Facility 

Name Pollutant 

Potential 

Emissions 

Pre- limit 

(tpy) 

PTE 2002 

SO2+NOx+

PM of BART 

- Eligible 

Equipment 

(tpy) 

Min 

distance 

to Nearest 

Class 1 

Area 

(km) 

Potential 

Emissions 

Post – limit 

(tpy) 

Effective 

Date 

Georgia 

Pacific – 

Cedar 

Springs 

SO2 8506.2 17684 137.1 

Power Boilers No. 

1 and No. 2 have 

limits of 135lbs/hr 

each. This 

equates to 591 

tpy. 

Recovery Boiler 

No. 3 has a limit of 

350 ppm on a dry 

basis corrected to 

8 percent oxygen 

as a 24-hour 

average when 

firing black liquor 

solids. This 

equates to 3600 

tpy. 

Facility wide limits 

are equivalent to 

4782.36 tpy. 

July 30, 

2011. 

LaFarge 

Building 

Materials* 

 -- 540 114.3 

No limit. Facility 

Exempt via Model 

Plant Exemption. -- 

International 

Paper – 

Savannah 

 -- 51.4 83.6 

No limit. Facility 

Exempt via Model 

Plant Exemption. -- 

*Note: After this analysis was completed, Lafarge Building Materials shut down and 

removed BART-eligible equipment resulting in a reduction of 531.4 tons of potential 

emissions of SO2 + NOx + PM effectively eliminating their eligibility to BART. 
Georgia Regional Haze State Implementation Plan 

107 of 124 

Georgia Pacific Cedar Springs was able to demonstrate exemption from BART by 

accepting SO2 emissions limits on Power Boilers 1 and 2 (135 lb/hr each) and on 

Recovery Boiler 3 (350 ppm). These limits result in 0.499 deciview impact at St. Marks 

and a 0.306 deciview impact at Okefenokee NWR. The permit will be issued with 

Federally-enforceable limits and a Federally- enforceable condition that requires the 

facility to monitor their emissions and to notify EPD if they exceed the BART exemption 

limit. 

EPA established specific exemption thresholds or criteria based on CALPUFF modeling 

conducted for a model plant. The criteria that sources must meet include potential 

emissions of SO2 and NOx combined of less than 500 tons per year and a distance of 

greater than 50km from any Class I area, or combined potential emissions less than 

1000 tons per year with a distance greater than 100km from any Class I area. In 

situations where combined SO2 and NOx emissions are less than 500 or 1000 tons per 

year, but PM emissions are greater than 15 tons per year, the emissions of SO2, NOx 

and PM may be combined using weighting factors (Appendix P) and compared to 500 

or 1000 tons. Both Lafarge Building Materials and International Paper – Savannah 

meet the model plant exemption criteria. Please see Table 7.7.2-2 for emissions and 

distances from Class I areas. 

One of Georgia’s BART-eligible sources is an EGU. This Georgia power plant Bowen is 

subjected to CAIR. US EPA has determined that, as a whole, the CAIR cap-and-trade 

program improves visibility more than implementing BART for individual sources in 

states affected by CAIR. A State that opts to participate in the CAIR program under 

Part 96 AAA-EEE need not require an affected BART-eligible EGU to install, operate, 

and maintain BART for SO2 or NOx emissions. Since Georgia is participating in CAIR 

and accepts US EPA’s overall finding that CAIR “substitutes” for BART for NOx and 

SO2, Georgia’s EGUs were allowed to submit BART exemption modeling 

demonstrations for PM emissions only. All EGUs other than Georgia Power-Plant 

Bowen demonstrated that they do not contribute to visibility impairment in any Class I 

area. 

In total, twenty-two of Georgia’s twenty-four BART-eligible sources were able to 

demonstrate that they did not cause or contribute to visibility impairment in any Class I 

area within 300 km of the source. 

7.7.3 BART Determination for Subject-to-BART Sources 

Two sources, Interstate Paper in Riceboro, Georgia, and Georgia Power Plant Bowen in 

Cartersville, Georgia, were unable to demonstrate a contribution of less than 0.5 dv at 

all Class I areas within 300 km from their BART-eligible sources. These two sources are 

considered to be “subject to BART” and were required to do a complete BART 

determination containing their evaluation of potential BART options and accordingly 

submit permit applications. Interstate Paper failed to perform a BART determination, 

therefore the analysis was performed by EPD and the results presented are those 
Georgia Regional Haze State Implementation Plan 

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determined by EPD. Their BART determination results are give in table 7.7.3-1, for a 

more detailed discussion of the BART determinations, please see Appendix H.8. 

Table 7.7.3-1 BART determination results for subject-to BART sources 

Source Unit 

Required 

Control Option 

Control 

Efficiency 

Cost of 

Control 

($/ton) 

Power Boiler 

(F1) 

Combustion of 

natural gas only 

except during 

periods of 

curtailment 

99% 370 

Recovery 

Boiler 

No cost effective 

control options 

Available 

Not required Not required 

Interstate 

Paper 

Lime Kiln No cost effective 

control options 

Available 

Not required Not required 

Boiler 1 

Boiler 2 

Boiler 3 

Georgia 

Power 

Company – 

Plant Bowen Boiler 4 

No cost effective 

control options 

Available 

Not required Not required 

Figure 7.7.3-1 shows the locations of facilities with emission units eligible for BART 

analysis. In addition, the basis for reduction or no reduction is indicated for each facility. 

The required operational restrictions will be implemented by adding them as permit 

conditions to the Title V operating permit of Interstate Paper (see Appendix M). Georgia 

EPD has notified Interstate Paper in writing of the intent to revise its air permit. 

Recordkeeping, monitoring, and testing requirements will be included to demonstrate 

compliance with the limits. These requirements will be consistent with Georgia EPD’s 

Procedures for Testing and Monitoring Sources of Air Pollutants (PTM) and must meet 

the requirements of Compliance Assurance Monitoring (40 CFR Part 64) or Periodic 

Monitoring [40 CFR 70.6(3)(i)(B)], as appropriate. 
Georgia Regional Haze State Implementation Plan 

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Figure 7.7.3-1. Locations of facilities with BART-eligible emission units. 
Georgia Regional Haze State Implementation Plan 

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7.8 What Additional Emissions Controls Were Considered as Part of the LongTerm Strategy for Visibility Improvement by 2018? 

Section 308(d)(3)(v) of the regional haze rule lists several factors that must be 

addressed in each SIP. These factors include smoke management techniques for 

agricultural and forestry management purposes and measures to mitigate emissions 

from construction activities. 

As discussed in Section 2.4 and demonstrated in Figures 2.4-1 and 2.4-2, elemental 

carbon (sources include agriculture, prescribed wildland fires, and wildfires) is a 

relatively minor contributor to visibility impairment at the Class I areas in Georgia. 

However, on July 11, 2008, GA EPD entered into a memorandum of understanding with 

the Georgia Forestry and Georgia Department of Natural Resources Wildlife Resources 

Division adopting a smoke management plan that addresses the issues laid out in US 

EPA’s 1998 draft guidance for smoke management plans. This plan is sufficient to 

satisfy the directive in section 308(d)(3)(v)(E). A copy of the current smoke 

management plan can be obtained from Georgia EPD, or it can be viewed on the 

Georgia EPD web page. 

Georgia’s Rules for Air Quality Control include requirements for precautions to prevent 

fugitive dust from becoming airborne and also limit the opacity of fugitive emissions to 

less than 20 percent. The requirements of rule 391-3-1-.02(n) include preventive 

measures for construction activities and are deemed adequate to satisfy the directive in 

Section 308(d)(3)(v)(B) of the Regional Haze rule. The current version of Georgia’s air 

rules is available on the Georgia EPD web site. 
Georgia Regional Haze State Implementation Plan 

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8.0 REASONABLE PROGRESS GOALS 

The Regional Haze Rule at 40 CFR section 51.308(d)(1) requires States to establish 

reasonable progress goals for each Class I area within the state (expressed in 

deciviews) that provide for reasonable progress towards achieving natural visibility. In 

addition, US EPA released guidance on June 1, 2007, to use in setting reasonable 

progress goals. The goals must provide improvement in visibility for the most impaired 

days, and ensure no degradation in visibility for the least impaired days over the State 

Implementation Plan (SIP) period. The state must also provide an assessment of the 

number of years it would take to attain natural visibility conditions if improvement 

continues at the rate represented by the reasonable progress goal. 

In accordance with the requirements of 40 CFR §51.308(d)(1), this Regional Haze 

Implementation Plan establishes reasonable progress goals for each Class I area in 

Georgia. To calculate the rate of progress represented by each reasonable progress 

goal, GA EPD compared baseline visibility conditions to natural visibility conditions in 

each Class I area and determined the uniform rate of visibility improvement (in 

deciviews) that would need to be maintained during each implementation period in order 

to attain natural visibility conditions by 2064. The GA EPD summarized expected 

visibility improvements under existing Federal and State regulations, BART 

determinations in Georgia and neighboring states, and any additional control measures 

found to be reasonable to implement in this review period. These controls were 

modeled in CMAQ as part of the long-term strategy (Appendix E) and the reasonable 

progress goals were then adjusted for additional controls in Georgia (Appendix N). 

VISTAS has demonstrated that the 2018 Base G4 control scenario provides for a 

significant improvement in visibility better than the uniform rate of progress for at least 

one of the three Georgia Class I areas and the other two falling short by less than 10 

percent for the most impaired days over the period of the implementation plan and 

ensures no degradation in visibility at any of the three Georgia Class I areas for the 

least impaired days over the same period. Implementation of Georgia’s reasonable 

progress goals in the form of BART and 4-factor analyses controls will give further 

visibility improvement by 0.02 dV (0.088%) at Cohutta Wilderness Area and 0.05 dV 

(0.21%) at Okefenokee Wilderness area and Wolf Island. These reductions can be 

seen in Figure 8.0-1 and 8.0-2. Since there is not an IMPROVE monitor located at Wolf 

Island, the Okefenokee uniform rate of progress glide slope and reasonable progress 

goals are being used as a surrogate for Wolf Island. Since the Okefenokee Wilderness 

and Wolf Island reasonable progress goals show a slower rate of improvement in 

visibility than the rate that would be needed to attain natural conditions by 2064 (uniform 

rate of progress glide slope), it has been estimated that an additional 6-7 years are 

need to attain natural conditions. 

Note that GA EPD has not taken into account any reductions that will result from 

Florida’s reasonable progress analysis as required 40 CFR 51.308(d)(1). Florida DEP 

has proposed requiring submittal of applications to address Reasonable Progress 

Control Technology no later than January 31, 2012. As explained in Appendix H, point 
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sources in Florida have a larger impact on visibility impairment at Okefenokee than 

Georgia sources and have a significant impact on Wolf Island. SO2 controls at Florida 

Sources can, therefore, have a significant impact on reasonable progress at 

Okefenokee and Wolf Island. Because the reasonable controls required of Florida 

sources are not yet available, they have not been taken into account in setting 

reasonable progress goals for Okefenokee or Wolf Island. 

Table 8.0-1. Georgia Reasonable Progress Goals – 20 percent Worst Days 

Class I 

Area 

2004 

Baseline 

Visibility (dv) 

2018 Reasonable 

Progress Goal 

(dv) 

[2004 – 2018 

decrease] 

2018 Uniform 

Rate of Progress 

Glide Slope (dv) 

[2004 – 2018 

decrease to meet 

uniform progress] 

Natural 

Visibility (dv) 

 

 [2018-2064 

decrease 

needed from 

2018 goal] 

 

Cohutta 

Wilderness 

30.25 22.78 

[7.47] 

25.71 

[4.54] 

10.78 

[12.00] 

Okefenokee 

Wilderness 

27.13 23.77 

[3.36] 

23.42 

[3.71] 

11.21 

[12.56] 

Wolf Island 27.13 23.77 

[3.36] 

23.42 

[3.71] 

11.21 

[12.56] 

 

Table 8.0-2. Georgia Reasonable Progress Goals – 20 percent Best Days 

Class I 

Area 

2004 and 2018 Baseline 

Visibility (dv) 

2018 Reasonable Progress 

Goal (dv)

[2004 – 2018 improvement 

goal] 

Cohutta 

Wilderness 

13.77 11.75 

[2.02] 

Okefenokee 

Wilderness 

15.23 13.92 

[1.31] 

Wolf Island 15.23 13.92 

[1.31] 

 
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Figure 8.0-1. CMAQ 2018 Base G4 results compared to Uniform Rate of Progress at Cohutta 

Wilderness Area with GA Reasonable Progress Goals 

Figure 8.0-2. CMAQ 2018 Base G4 results compared to Uniform Rate of Progress at Okefenokee 

Wilderness Area with GA Reasonable Progress Goals 

Uniform Rate of Progress Glide Path

Cohutta - Worst 20% Data Days

New IMPROVE Equation

30.25

28.63

25.71

22.46

19.22

15.97

12.73

10.78

27.05

22.78

0

5

10

15

20

25

30

35

2000 2004 2008 2012 2016 2020 2024 2028 2032 2036 2040 2044 2048 2052 2056 2060 2064

Year

Haziness Index (Deciviews)

Glide Path Natural Condition (Worst Days) Observation Model Prediction

Uniform Rate of Progress Glide Path

Okefenokee - Worst 20% Data Days

New IMPROVE Equation

27.13 25.81

23.42

20.76

18.11

15.45

12.80

11.21

25.38

23.77

0

5

10

15

20

25

30

35

2000 2004 2008 2012 2016 2020 2024 2028 2032 2036 2040 2044 2048 2052 2056 2060 2064

Year

Haziness Index (Deciviews)

Glide Path Natural Condition (Worst Days) Observation Model Prediction
Georgia Regional Haze State Implementation Plan 

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9.0 MONITORING STRATEGY 

The State Implementation Plan is to be accompanied by a strategy for monitoring 

regional haze visibility impairment. Specifically, the Regional Haze Rule states at 40 

CFR 51.308(d)(4): 

“(4) Monitoring strategy and other implementation plan requirements. The State 

must submit with the implementation plan a monitoring strategy for measuring, 

characterizing, and reporting of regional haze visibility impairment that is 

representative of all mandatory Class I Federal areas within the State. This 

monitoring strategy must be coordinated with the monitoring strategy required in 

§51.305 for reasonably attributable visibility impairment. Compliance with this 

requirement may be met through participation in the IMPROVE network. The 

implementation plan must also provide for the following: 

(i) The establishment of any additional monitoring sites or equipment 

needed to assess whether reasonable progress goals to address regional 

haze for all mandatory Class I Federal areas within the State are being 

achieved. 

(ii)-(vi) [Other implementation plan requirements that pertain to reporting 

and use of monitoring data and an emission inventory.]”

Such monitoring is intended to provide the data needed to satisfy four objectives: 

1. Track the expected visibility improvements resulting from emissions 

reductions identified in this SIP; 

2. Better understand the atmospheric processes of importance to haze; 

3. Identify chemical species in the ambient particulate matter and relate them to 

emissions from sources; and 

4. Evaluate regional air quality models for haze and construct relative response 

factors (RRFs) for using those models.

The primary monitoring network for regional haze is the IMPROVE network. Given that 

IMPROVE monitoring data from 2000-2004 serve as the baseline for the regional haze 

program, the future regional haze monitoring strategy must necessarily be based on, or 

directly comparable to, IMPROVE. The IMPROVE measurements provide the only 

long-term record available for tracking visibility improvement or degradation and, 

therefore, Georgia intends to rely on the IMPROVE network for complying with the 

regional haze monitoring requirement in the Regional Haze Rule. There are currently 

two IMPROVE sites in the State. 
Georgia Regional Haze State Implementation Plan 

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Table 9.0-1. Class I areas in Georgia and IMPROVE monitors that represent 

conditions at each of them. 

Class I Area IMPROVE Site Designation

Cohutta Wilderness Area COHU1 

Okefenokee Wilderness Area OKEF1 

GA EPD will use South Eastern Aerosol Research and Characterization (SEARCH) 

data from the sites illustrated below for further the understanding of both PM2.5 and 

visibility formation and trends in Georgia. The SEARCH monitors provides the following 

data related to the nature of ambient fine particulate matter: 

• 24-hr PM2.5 filter samples, analyzed for mass, ions (sulfate, nitrate, ammonium), 

organic carbon (OC), elemental (black) carbon (EC or BC), and elements as 

measured by X-ray fluorescence (XRF); 

• 24-hr PM coarse mass, ions, and XRF elements; 

• 24-hr gaseous ammonia as collected with an annular denuder; 

• Continuous (minute to hourly) PM2.5 mass, OC, EC, ammonium, nitrate, and 

sulfate; light scattering and light absorption; 

• Continuous gaseous ozone, nitric oxide, nitrogen dioxide, total oxidized nitrogen 

(NOy), nitric acid, carbon monoxide, and sulfur dioxide; and 

• Continuous 10-m meteorological parameters: wind speed, wind direction, 

precipitation, temperature, barometric Pressure, relative humidity and solar 

radiation.

The Clean Air Status and Trends Network (CASTNet) provides atmospheric data on the 

dry deposition component of total acid deposition, ground-level ozone and other forms 

of atmospheric pollution. All measurements utilize a 1-week sample period and include 

sulfur dioxide, particulate sulfate, particulate nitrate, nitric acid, particulate ammonium, 

particulate calcium, particulate sodium, particulate magnesium, particulate potassium, 

and ozone. In addition, GA EPD operates a fairly comprehensive PM2.5 network of the 

filter-based Federal reference method (FRM) monitors, continuous mass monitors 

(TEOMs), filter-based speciated monitors (STN) and the continuous speciated monitors 

described above. A map of the various locations around the State is included in Figure 

9.0.1. These PM2.5 measurements help GA EPD characterize air pollution levels in 

areas across the state, and, therefore, aid in the analysis of visibility improvement in 

and near the Class I areas. 
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Figure 9.0-1. PM2.5 Monitoring Network in Georgia 

The IMPROVE measurements are central to Georgia’s regional haze monitoring 

strategy, and it is difficult to visualize how the objectives listed above could be met 

without the monitoring provided by IMPROVE. Any reduction in the scope of the 

IMPROVE network in Georgia would jeopardize the State’s ability to demonstrate 

reasonable progress toward visibility improvement in some of its Class I areas. In 

particular, Georgia’s regional haze strategy relies on emission reductions that will on 

different timelines and will most likely not be spatially uniform. 

Because each of the current IMPROVE monitors in Georgia represents a different 

airshed, reduction of the IMPROVE network by shutting down one of these monitoring 

sites impedes tracking progress at reducing haze at the affected Class I area. In the 

event this occurs, Georgia, in consultation with the US EPA and relevant Federal Land 

Managers, will develop an alternative approach for meeting the tracking goal, perhaps 
Georgia Regional Haze State Implementation Plan 

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by seeking contingency funding to carry out limited monitoring or by relying on data from 

nearby urban monitoring sites to demonstrate trends in speciated PM2.5 mass. 

Data produced by the IMPROVE monitoring network will be used nearly continuously for 

preparing the 5-year progress reports and the 10-year SIP revisions, each of which 

relies on analysis of the preceding five years of data. Consequently, the monitoring 

data from the IMPROVE sites needs to be readily accessible and to be kept up to date. 

Presumably, IMPROVE will continue to process information from its own measurements 

at about the same pace and with the same attention to quality as it has shown in the 

recent past. The VIEWS web site has been maintained by VISTAS and the other 

Regional Planning Organizations (RPOs) to provide ready access to the IMPROVE data 

and data analysis tools. Georgia is encouraging VISTAS and the other RPOs to 

maintain VIEWS or a similar data management system to facilitate analysis of the 

IMPROVE data. 
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10.0 INTERSTATE CONSULTATION 

The VISTAS states have jointly developed the technical analyses to define the visibility 

improvement by 2018 under existing Federal and State regulations compared to the 

uniform rate of progress, SO2 Areas of Influence for each Class I area, and methods to 

prioritize contributions from individual sources within the Areas of Influence. The states 

collectively accept the conclusions of these analyses. 

In December of 2006, the VISTAS State Air Directors held their first formal consultation 

meeting to review the Base G modeling results and the SO2 Areas of Influence 

analyses. The Air Directors agreed to look at reasonable control measures for sources 

on the lists for the SO2 Areas of Influence. Each state would consider sources within 

their state and would identify sources in neighboring states that they would like to have 

that neighboring state consider. States acknowledged that the review process would 

differ among states since some Class I areas are projected to see visibility 

improvements near the uniform rate of progress while most Class I areas are projected 

to have greater improvements than uniform rate of progress. 

In May of 2007, the VISTAS State Air Directors met for their second formal interstate 

consultation. States shared their lists of sources in their state and neighboring states 

for each Class I area. They also shared their criteria for listing sources and their plans 

for further interstate consultation. 

The GA EPD received consultation letters and evaluated the impact of Georgia sources 

on Class I areas in neighboring states and identified sources that were likely to 

contribute 0.5% or more to the total visibility impairment. Such sources were 

considered for additional reasonable control measures that should be implemented to 

mitigate impacts in Class I areas in neighboring states. 

Based on the VISTAS Area of Influence (AOI) electronic spreadsheet that includes Q/d, 

RTMax, and percent contribution from each Georgia point source to each Class I area, the 

following seven nearby Class I areas outside of Georgia showed impacts greater than or 

equal to 0.5%: Joyce Kilmer-Slickrock (NC), Shining Rock (NC), Great Smoky Mountains 

(NC/TN), Sipsey Wildernesses (AL), Cape Romain (SC), Swanquarter (NC), and St. Marks 

(FL). All other Class I areas showed contributions from Georgia point sources of less than 

0.5%. For details on specific percent contribution from each Georgia point source to each 

Class I area, see Appendix H.2. For a list of pollution reductions that are anticipated at 

each source before 2018, see Section 7.6.1. 
Georgia Regional Haze State Implementation Plan 

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Table 10-1: Georgia point source contribution to Joyce Kilmer-Slickrock (NC). 

Plant Point ID Percent Contribution 

GEORGIA POWER COMPANY, YATES STEAM-ELECT SG07 1.879%

GEORGIA POWER COMPANY, YATES STEAM-ELECT SG06 1.861%

GEORGIA POWER COMPANY, SCHERER STEAM-ELE SG03 1.559%

GEORGIA POWER COMPANY, SCHERER STEAM-ELE SG04 1.496%

GEORGIA POWER COMPANY, SCHERER STEAM-ELE SG01 1.476%

GEORGIA POWER COMPANY, SCHERER STEAM-ELE SG02 1.466%

GEORGIA POWER COMPANY, BOWEN STEAM-ELECT SG04 1.100%

GEORGIA POWER COMPANY, BOWEN STEAM-ELECT SG03 1.068%

INLAND PAPERBOARD & PACKAGING, INC. -LIN F4 0.995%

GEORGIA POWER COMPANY, HAMMOND STEAM-ELE SG04 0.924%

GEORGIA POWER COMPANY, BOWEN STEAM-ELECT SG02 0.850%

GEORGIA POWER COMPANY, BOWEN STEAM-ELECT SG01 0.844%

GEORGIA POWER COMPANY, YATES STEAM-ELECT SG05 0.755%

GEORGIA POWER COMPANY, YATES STEAM-ELECT SG04 0.739%

Table 10-2: Georgia point source contribution to Shining Rock (NC). 

Plant Point ID Percent Contribution 

GEORGIA POWER COMPANY, SCHERER STEAM-ELE SG03 0.712%

GEORGIA POWER COMPANY, SCHERER STEAM-ELE SG04 0.683%

GEORGIA POWER COMPANY, SCHERER STEAM-ELE SG01 0.674%

GEORGIA POWER COMPANY, SCHERER STEAM-ELE SG02 0.669%

GEORGIA POWER COMPANY, YATES STEAM-ELECT SG07 0.580%

GEORGIA POWER COMPANY, YATES STEAM-ELECT SG06 0.574%

Table 10-3: Georgia point source contribution to Great Smoky Mountains (NC/TN). 

Plant Point ID Percent Contribution 

GEORGIA POWER COMPANY, YATES STEAM-ELECT SG07 0.688% 

GEORGIA POWER COMPANY, YATES STEAM-ELECT SG06 0.681% 

GEORGIA POWER COMPANY, SCHERER STEAM-ELE SG03 0.636% 

GEORGIA POWER COMPANY, SCHERER STEAM-ELE SG04 0.610% 

GEORGIA POWER COMPANY, SCHERER STEAM-ELE SG01 0.602% 

GEORGIA POWER COMPANY, SCHERER STEAM-ELE SG02 0.598% 

Table 10-4: Georgia point source contribution to Swanquarter (NC). 

Plant Point ID Percent Contribution 

INTERNATIONAL PAPER - SAVANNAH MILL PB13 0.859% 

SAVANNAH ELECTRIC: MCINTOSH STEAM - ELEC SG01 0.720% 
Georgia Regional Haze State Implementation Plan 

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Table 10-5: Georgia point source contribution to Sipsey Wildernesses (AL). 

Plant Point ID Percent Contribution 

GEORGIA POWER COMPANY, YATES STEAM-ELECT SG07 1.115% 

GEORGIA POWER COMPANY, YATES STEAM-ELECT SG06 1.104% 

GEORGIA POWER COMPANY, SCHERER STEAM-ELE SG03 0.587% 

GEORGIA POWER COMPANY, SCHERER STEAM-ELE SG04 0.563% 

GEORGIA POWER COMPANY, SCHERER STEAM-ELE SG01 0.555% 

GEORGIA POWER COMPANY, SCHERER STEAM-ELE SG02 0.551% 

Table 10-6: Georgia point source contribution to Cape Romain (SC). 

Plant Point ID Percent Contribution 

INTERNATIONAL PAPER - SAVANNAH MILL PB13 1.553% 

SAVANNAH ELECTRIC: MCINTOSH STEAM - ELEC SG01 1.352% 

SAVANNAH ELECTRIC: KRAFT STEAM - ELECTRI SG03 0.814% 

Table 10-7: Georgia point source contribution to St. Marks (FL). 

Plant Point ID Percent Contribution 

GEORGIA POWER COMPANY, MITCHELL STEAM-EL SG03 2.737% 

LONGLEAF ENERGY STATION BOIL1 1.392% 

LONGLEAF ENERGY STATION BOIL2 1.392% 

GEORGIA PACIFIC CORPORATION, CEDAR SPRIN U501 1.128% 

GEORGIA PACIFIC CORPORATION, CEDAR SPRIN U500 1.081% 

GEORGIA PACIFIC CORPORATION, CEDAR SPRIN R402 0.768% 

INTERNATIONAL PAPER - SAVANNAH MILL PB13 0.704% 

SAVANNAH ELECTRIC: MCINTOSH STEAM - ELEC SG01 0.554% 

The GA EPD also sent consultation letters to Florida, South Carolina and Tennessee 

regarding the impact of their sources on Georgia’s Class I areas. These consultation 

letters are present in Appendix J. 

Analyses of impacts from Georgia and potential controls are discussed in greater detail 

in Appendix H. 

The MANE-VU states of Maine, New Jersey, New Hampshire, and Vermont sent letters 

to Georgia in the Spring of 2007 stating that, based on 2002 emissions, Georgia 

contributed to visibility impairment to Class I areas in those states. MANE-VU states 

have asked the GA EPD to participate in further consultation with these states during 

the Summer of 2007. The GA EPD has responded to those letters and has participated 

in conference calls with these states. The final Regional Haze SIP will reflect the results 

of those letters and calls. The letters from these states, and responses from GA EPD, 

are included as attachments to Appendix J. 
Georgia Regional Haze State Implementation Plan 

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11.0 COMPREHENSIVE PERIODIC IMPLEMENTATION PLAN 

REVISIONS 

40 CFR Section 51.308(f) requires the GA EPD to revise its regional haze 

implementation plan and submit a plan revision to US EPA by July 31, 2018, and every 

ten years thereafter. In accordance with the requirements listed in Section 51.308(f) of 

the Federal rule for regional haze, Georgia commits to revising and submitting this 

regional haze implementation plan by July 31, 2018, and every ten years thereafter. 

In addition, Section 51.308(g) requires periodic reports evaluating progress towards the 

reasonable progress goals established for each mandatory Class I area. In 

accordance with the requirements listed in Section 51.308(g) of the Federal rule for 

regional haze, the GA EPD commits to submitting a report on reasonable progress to 

US EPA every five years following the initial submittal of the SIP. The report will be in 

the form of a SIP revision. The reasonable progress report will evaluate the progress 

made towards the reasonable progress goal for each mandatory Class I area located 

within Georgia and in each mandatory Class I area located outside Georgia which may 

be affected by emissions from within Georgia. 

The requirements listed in 51.308(g) include the following: 

1. Description of the status of implementation; 

2. Summary of emission reductions achieved thus far, including especially the 

status of implementation of the CAIR compliance plans for EGUs compared to 

the control assumed in the modeling. [The GA EPD recognizes that the 2018 

projections of EGU controls from the IPM runs represent one solution to how the 

CAIR requirements will be met. By the time of the first periodic report, the GA 

EPD anticipates that the actual compliance strategy for the various utility 

companies will be much more defined. An assessment of those actual 

compliance plans will be done for the first periodic report.] 

3. Assessment of changes in visibility conditions at each Class I area (current vs. 

baseline), expressed as 5-year averages of annual values for 20 percent best 

and worst days; 

4. Analysis of emission changes over the 5-year period identified by source or 

activity; 

5. Analysis of any significant changes in or out of the State which have impeded 

progress; 

6. Assessment of the sufficiency of the implementation plan to meet RPGs; 

7. Review and any modifications to Georgia’s visibility monitoring plan.

All requirements listed in 51.308(g) shall be addressed in the SIP revision for 

reasonable progress. 
Georgia Regional Haze State Implementation Plan 

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There are several technical improvements that are recommended in the emissions 

inventory and air quality models that are used to support regulatory decisions for 

regional haze. These recommended improvements, as funding is available, will be 

implemented to support the next long-term strategy. Appendix K contains a more 

detailed discussion of possible technical improvements. The following is an overall 

summary: 

First and foremost, continued improvements are needed in the integrated oneatmosphere air quality models that are used to project air quality responses to 

emissions reductions. As our understanding of partitioning between gaseous and 

aerosol phases improves, this understanding needs to be reflected in the models. 

Improvements can also be made in how the models handle individual pollutants. 

Sulfate performance for the CMAQ regional air quality model is good overall. However 

sulfate deposition is frequently overestimated in the models, particularly in the summer 

months. At the coastal sites, when winds are blowing from the Gulf of Mexico or 

Atlantic Ocean, CMAQ underestimates measured sulfate at the monitors. CMAQ’s 

processes also should be reviewed for sulfate formation over water. Nitrate is 

overestimated by the model in the winter and underestimated in the summer, although 

summer monitored values of nitrates are very low. Additional improvements in seasonal 

allocation of ammonia emissions would improve model estimates of ammonium nitrate 

formation. Organic carbon is generally underestimated in the summer months. 

Improvements are needed in the characterization of both primary carbon emissions and 

formation of secondary organic carbon.

Other improvements needed include better tools for organic carbon source 

apportionment, and more consistent measurement techniques between rural and urban 

monitoring networks. To improve our understanding of the contribution of fire from 

natural forest fires, prescribed burning, land clearing, and agricultural burning, states 

need improved record keeping. Additional improvements to international emissions 

inventory are also needed, to improve our understanding of boundary conditions for our 

modeling domain and of the contributions from international emissions to pollutant 

concentrations at the VISTAS Class I areas. 
Georgia Regional Haze State Implementation Plan 

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12.0 DETERMINATION OF ADEQUACY OF THE EXISTING PLAN 

Depending on the findings of the 5-year progress report, Georgia commits to taking one 

of the actions listed in 40 CFR section 51.308(h). The findings of the 5-year progress 

report will determine which action is appropriate and necessary. 

List of Possible Actions – 40 CFR Section 51.308(h)

1) GA EPD determines that the existing SIP requires no further substantive revision 

in order to achieve established goals. GA EPD provides to the Administrator a 

negative declaration that further revision of the SIP is not needed at this time. 

2) GA EPD determines that the existing SIP may be inadequate to ensure 

reasonable progress due to emissions from other states which participated in the 

regional planning process. GA EPD provides notification to the Administrator and 

the states that participated in regional planning. GA EPD collaborates with states 

through the regional planning process to address the SIP’s deficiencies. 

3) GA EPD determines that the current SIP may be inadequate to ensure 

reasonable progress due to emissions from another country. GA EPD provides 

notification, along with available information, to the Administrator. 

4) GA EPD determines that the existing SIP is inadequate to ensure reasonable 

progress due to emissions within the state. GA EPD will revise its SIP to address 

the plan’s deficiencies within one year. 

13.0 COORDINATION WITH FEDERAL LAND MANAGERS 

As required by 40 CFR §51.308(i), the regional haze SIP must include procedures for 

continuing consultation between the States and Federal Land Managers (FLMs) 

pertaining to visibility protection. The FLMs responsible for Class I areas in Georgia 

are: 

· Fish and Wildlife Service (FWS), under U.S. Department of Interior 

· National Park Service (NPS), under U.S. Department of Interior 

· Forest Service (FS), under U.S. Department of Agriculture 

The requirements for ongoing State and FLMs consultation and how Georgia will 

comply with the requirements are described in the following paragraphs. 

40 CFR 51.308(i)(2) requires the State to provide the FLMs with an opportunity for 

consultation, in person and at least 60 days prior to holding a public hearing on a SIP 

revision. The consultation must include the opportunity for the FLMs to discuss their: 
Georgia Regional Haze State Implementation Plan 

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· assessment of visibility impairment in the Class I area; and 

· recommendations on the development of the reasonable progress goal and on 

the development and implementation of strategies to address visibility 

impairment. 

Records of Georgia EPD’s consultations with the FLMs on the first Regional Haze SIP 

are included in Appendix O. 

40 CFR 51.308(i)(3) requires the State to incorporate into any SIP or SIP revision a 

description of how it addressed comments provided by the FLMs. The comments on 

the SIP and the description of how they were addressed have been included in 

Appendix O. 

40 CFR 51.308(i)(4) requires the plan (or plan revision) to include procedures for 

continuing consultation between the State and Federal Land Managers on the 

implementation of the visibility protection program, including development and review of 

implementation plan revisions and 5-year progress reports, and on the implementation 

of other programs having the potential to contribute to impairment of visibility in 

mandatory Class I Federal areas. GA EPD will offer the Federal Land Managers an 

opportunity for consultation on a yearly basis, including the opportunity to discuss the 

implementation process and the most recent IMPROVE monitoring data and VIEWS 

data. Records of annual consultations and progress report consultations will be 

maintained in Georgia EPD’s Regional Haze files.