Georgia's Redesignation Request and 

Maintenance Plan for the Floyd County 

Nonattainment Area for the 1997 PM2.5 NAAQS 

May 30, 2012 

Prepared by:

Georgia Department of Natural Resources 

Environmental Protection Division 

Air Protection Branch 
 ii 

Executive Summary 

This document contains Georgia's request under the Clean Air Act Amendments of (CAA) of 1990 that 

the Floyd County nonattainment area be redesignated to attainment with respect to the annual National 

Ambient Air Quality Standard (NAAQS) for PM2.5 (1997 fine particulate matter standard, retained in 

2006). The document also includes Georgia’s plan to maintain attainment of the PM2.5 standard in Floyd 

County. 

This request is based on three years, 2007-2009, of ambient monitoring data showing attainment of the 

standard (15.0 μg/m3) consistent with the clean data policy memo (Stephen Page 12/14/2004); the 

implementation of permanent and enforceable reductions in PM2.5 and PM2.5 precursor emissions; 

compliance with all applicable requirements; and the Floyd County Maintenance Plan with projections 

demonstrating maintenance of the standard through the year 2023. 
Floyd County PM2.5 Nonattainment Area 

Redesignation Request and Maintenance Plan 

iii 

TABLE OF CONTENTS 

1.0 Introduction ................................................................................................................. 1

1.1 Nonattainment Designation and Attainment Demonstration .......................................... 1

1.2 Redesignation Request ........................................................................................................ 2

1.3 Maintenance Plan ................................................................................................................ 3

2.0 Redesignation Request ................................................................................................. 4

2.1 Attainment of the Annual PM2.5 NAAQS .......................................................................... 4

2.1.1 Monitoring Network ........................................................................................................................ 4

2.1.2 Ambient PM2.5 Data ........................................................................................................................ 6

2.1.3 Clean Data Determination ............................................................................................................... 6

2.2 Implementation Plan Under Section 110(k) ...................................................................... 7

2.3 Permanent and Enforceable and Other Reductions in Emissions .................................. 7

2.3.1 Source Apportionment of Ambient PM2.5 ....................................................................................... 7

2.3.2 State Control Measures - Georgia ................................................................................................... 9

2.3.2.1 SO2 and NOx Controls and SO2 Limits ................................................................................. 10

2.3.2.2 Smoke Management Plan ..................................................................................................... 15

2.3.3 Federal Control Measures ............................................................................................................. 16

2.3.3.1 Clean Air Interstate Rule ...................................................................................................... 17

2.3.3.2 Tier 2 Vehicle Standards ...................................................................................................... 18

2.3.3.3 Heavy-Duty Gasoline and Diesel Highway Vehicles Standards & Ultra Low-Sulfur Diesel 

Rule ........................................................................................................................................ 18

2.3.3.4 Large Nonroad Diesel Engines Rule & Ultra Low-Sulfur Diesel Rule ................................ 18

2.3.3.5 Nonroad Large Spark-Ignition Engines and Recreational Engines Standard ....................... 19

2.3.3.6 NOx SIP Call in Surrounding States ..................................................................................... 19

2.3.4 SO2 Emissions Reductions in Upwind States ................................................................................ 19

2.4 Section 110 and Part D Requirements ............................................................................. 22

3.0 Maintenance Plan ...................................................................................................... 23

3.1 Maintenance Demonstration ............................................................................................ 23

3.1.1 Attainment Year Emissions Inventory .......................................................................................... 24

3.1.1.1 Point Sources ........................................................................................................................ 25

3.1.1.2 Nonpoint Sources ................................................................................................................. 26

3.1.1.3 Onroad Mobile Sources ........................................................................................................ 27

3.1.1.4 Nonroad Mobile Sources ...................................................................................................... 28

3.1.1.5 Summary of 2007 Emissions Inventory ............................................................................... 29

3.1.2 Projected Emissions Inventories ................................................................................................... 29

3.1.2.1 Methods and Projected Inventories ...................................................................................... 29

3.1.2.2 Point Sources ........................................................................................................................ 31

3.1.2.3 Nonpoint Sources ................................................................................................................. 33

3.1.2.4 Onroad Mobile Sources ........................................................................................................ 34

3.1.2.5 Nonroad Mobile Sources ...................................................................................................... 35

3.1.3 Emissions Projections Summary and Demonstration of Maintenance of Attainment ................... 36

3.1.4 Emissions Decreases ..................................................................................................................... 38

3.1.5 Verification of Continued Attainment ........................................................................................... 39
Floyd County PM2.5 Nonattainment Area 

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3.2 Contingency Provisions..................................................................................................... 39

3.2.1 Contingency Measure Triggers ..................................................................................................... 39

3.2.2 Schedule and Procedure for Adoption and Implementation of Contingency Measures ................ 40

3.2.3 Contingency Measures .................................................................................................................. 41

4.0 Motor Vehicle Emissions Budget ............................................................................... 43

4.1 Pollutants ........................................................................................................................... 43

4.2 Methodology ...................................................................................................................... 44

4.3 Motor Vehicle Emissions Budgets and Safety Margins ................................................. 45

5.0 Conclusion ................................................................................................................. 46

6.0 References .................................................................................................................. 49
Floyd County PM2.5 Nonattainment Area 

Redesignation Request and Maintenance Plan 

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LIST OF FIGURES 

Figure 1-1. PM2.5 Nonattainment Areas in Georgia ........................................................................ 1

Figure 2-1. Locations of Floyd County PM2.5 sampling sites. ......................................................... 5

Figure 2-2: Average factor contributions for 2003-04 at the Atlanta, Floyd County, and Macon 

STN sites using PMF ................................................................................................................... 8

Figure 2-3. Locations and 2007 Energy Production of Coal-fired EGU Facilities in North 

Georgia ....................................................................................................................................... 11

Figure 2-4. SO2 Emissions and Generation from Plant Hammond, 2003 - 2009 ........................ 14

Figure 2-5. SO2 Emissions and Generation from North Georgia Coal-fired EGU Facilities, 

2003 - 2009 ................................................................................................................................. 14

Figure 2-6. Trend of Aggregated Annual SO2 Emissions in States With Downwind 

Contributions to Georgia PM2.5 Exceeding 0.15 μg/m3

 .......................................................... 22
Floyd County PM2.5 Nonattainment Area 

Redesignation Request and Maintenance Plan 

vi 

LIST OF TABLES 

Table 1-1. PM2.5 Design Value for Floyd County ............................................................................. 2

Table 2-1. Floyd Co. PM2.5 Data Collection Sites............................................................................. 6

Table 2-2. Annual and Three-year Average Ambient PM2.5 Concentrations ................................. 6

Table 2-3. Average factor contributions to PM2.5 (μg/m3

) for 2003-04 at the Atlanta, Floyd 

County, and Macon STN sites using PMF ................................................................................ 9

Table 2-4. Timetable of State Measure Implementation ............................................................... 10

Table 2-5. Annual SO2 Emissions and Generation (106 MWh) from North Georgia Coal-fired 

EGU Facilities, 2003 - 2009 ...................................................................................................... 13

Table 2-6. Timetable of Federal Measure Implementation .......................................................... 17

Table 2-7. Annual SO2 Emissions in States With Downwind Contributions to Georgia PM2.5

Exceeding 0.15 μg/m3 ................................................................................................................ 21

Table 3-1. 2007 Emissions Inventory Sources ................................................................................ 24

Table 3-2. Point Source Emissions for 2007 (tons, annual) ........................................................... 25

Table 3-3. Non-EGU Point Source Emissions for 2007 (tons, annual) ......................................... 25

Table 3-4. Nonpoint Source Emissions for 2007 (tons, annual) .................................................... 27

Table 3-5. Largest Nonpoint PM2.5 Emissions by Source Classification ...................................... 27

Table 3-6. Onroad Mobile Source Emissions for 2007 (tons, annual) .......................................... 28

Table 3-7. Nonroad Mobile Source Emissions for 2007 (tons, annual) ........................................ 29

Table 3-8. Attainment-year (2007) Emissions Inventory (tons, annual) ...................................... 29

Table 3-9. Bases of Control and Growth Factors for 2017 and 2023 Inventories ....................... 30

Table 3-10. Projected Point Source Emissions (tons) .................................................................... 32

Table 3-11. Non-EGU Point Source Emissions for 2023 (tons, annual) ....................................... 32

Table 3-12. Projected Nonpoint Source Emissions (tons) ............................................................. 33

Table 3-13. Largest Nonpoint PM2.5 Emissions by Source Classification, Year 2023 ................. 34

Table 3-14. Projected Onroad Mobile Source Emissions (tons) ................................................... 35

Table 3-15. Projected Nonroad Mobile Source Emissions (tons) ................................................. 36

Table 3-16. Projected Emissions – Total of All Sectors (tons) ....................................................... 37

Table 3-17. PM2.5 Speciation Data ................................................................................................... 37

Table 3-18. Emissions Decrease ....................................................................................................... 38

Table 4-1. 2023 Motor Vehicle Emissions, Emissions Budgets, and Safety Margins .................. 45

Table 5-1. Summary of Projected SO2 Emissions – Total of All Sectors (tons) ........................... 46

Table 5-2. Summary of Projected NOx Emissions – Total of All Sectors (tons) .......................... 47

Table 5-3. Summary of Projected PM2.5 Emissions – Total of All Sectors (tons) ........................ 47
Floyd County PM2.5 Nonattainment Area 

Redesignation Request and Maintenance Plan 

vii 

LIST of APPENDICES 

Appendix A Source Apportionment of PM2.5 in Georgia 

Appendix B Georgia’s Basic Smoke Management Plan and Memorandum of Understanding 

Appendix C Emissions Inventory Development for Floyd County 

Appendix C-1 Development of the Point Source Emissions Inventory for 2007 in the SESARM 

Region (Version 1.8), January 26, 2011 

Appendix C-2 Area and Nonroad 2007 Base Year Inventories, Final Report, June 2010 

Appendix C-3 Mobile Source Emissions Modeling for Floyd County PM2.5 Maintenance Plan 

Motor Vehicle Emissions Budget 

Appendix C-4 The Travel Demand Model for the Rome MPO 

Appendix C-5 Growth and Control Factors for Aircraft, Commercial Marine Vessel, and 

Locomotive Emissions (includes memorandum from K. Thesing and two 

spreadsheets) 

 

Appendix C-6 Documentation of the 2012 Projection Emission Inventory (VISTAS) 

Appendix C-7 Growth Factors for Nonpoint Sources and Non-EGU Point Sources 

Appendix C-8 MACTEC, August 2009. Point Source, On-road, and Fire Base Year, Future Year, 

and Control Strategy Emissions Inventories Draft Quality Assurance Project Plan 

 

Appendix C-9 E.H. Pechan and Associates, July 29, 2009. Quality Assurance Project Plan for Nonroad and Area Source Base Year and Future Year Emissions Inventories 
Floyd County PM2.5 Nonattainment Area 

Redesignation Request and Maintenance Plan 

viii 

List of Acronyms 

Acronym Meaning Acronym Meaning 

AEO Annual Energy Outlook FGD Flue Gas Desulfurization 

AERR Annual Emissions Reporting 

Requirements 

FR Federal Register 

AIRS Aerometric Information Retrieval 

System 

FRM Federal Reference Method 

AQS Air Quality Subsystem FRUTS Floyd-Rome Urban Transit Study 

CAA Clean Air Act GDOT Georgia Department of 

Transportation 

CAIR Clean Air Interstate Rule GFC Georgia Forestry Commission 

CARB California Air Resources Board HC Hydrocarbon 

CERR Consolidated Emissions Reporting 

Rule 

HPMS Highway Performance Monitoring 

System 

CFR Code of Federal Regulations ICI Industrial and 

Commercial/Institutional 

CO Carbon Monoxide MOU Memorandum of Understanding 

CSAPR Cross-state Air Pollution Rule MOVES Motor Vehicle Emissions Simulator 

DNR Department of Natural Resources MPO Metropolitan Planning Organization 

DOT Department of Transportation MVEB Motor Vehicle Emissions Budget 

EGAS Economic Growth Analysis System MWe Megawatt Electrical 

EGU Electric Generating Unit MWh Megawatt Hours 

EPA Environmental Protection Agency NAA Nonattainment Area 

EPD Environmental Protection Division NAAQS National Ambient Air Quality 

Standard 

ERTAC Eastern Regional Technical Advisory 

Committee 

NCD NMIM County Database 
Floyd County PM2.5 Nonattainment Area 

Redesignation Request and Maintenance Plan 

ix 

Acronym Meaning Acronym Meaning 

NEI National Emissions Inventory SCR Selective Catalytic Reduction 

NMIM National Mobile Inventory 

Model 

SEMAP Southeastern Modeling Analysis Plan 

NTE Not-To-Exceed SIP State Implementation Plan 

NOx Nitrogen Oxides SMP Smoke Management Plan 

OAQPS Office of Air Quality 

Planning and Standards 

SO2 Sulfur Dioxide 

PM Particulate Matter SOA Secondary Organic Aerosols 

PM2.5 Fine Particulate Matter STN Speciated Trends Network 

PMF Positive Matrix Factorization tpy Tons Per Year

ppm parts per million SUV Sport Utility Vehicle 

RACM Reasonably Available Control 

Measures 

ULSD Ultra-Low Sulfur Diesel 

RACT Reasonably Available Control 

Technology 

VISTAS Visibility Improvement State and Tribal 

Association of the Southeast 

RFP Reasonable Further Progress VMT Vehicle Miles Traveled 

SCC Source Classification Code WRD Wildlife Resources Division 
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1.0 Introduction 

This document contains the technical support for the Georgia Environmental Protection Division's 

(EPD’s) request that the Floyd County nonattainment area be redesignated as an area attaining the 

1997 annual fine particulate matter (PM2.5) National Ambient Air Quality Standard (NAAQS) 

pursuant to Sections 107(d)(3)(D) and (E) of the Clean Air Act (CAA), as amended. This 

redesignation request was prepared in accordance with U.S. EPA Guidance issued in 1992 

(memorandum dated September 4 of that year from John Calcagni1

). 

1.1 Nonattainment Designation and Attainment Demonstration 

In 2005, EPA designated four PM2.5 nonattainment areas in Georgia: Chattanooga (which also 

includes parts of Alabama and Tennessee), Floyd County, Atlanta, and Macon. Figure 1-1 shows 

their locations. The Floyd County nonattainment area is located in the northwest portion of the state

and south of Georgia’s portion of the Chattanooga Nonattainment Area. 

Figure 1-1. PM2.5 Nonattainment Areas in Georgia 

 

1

 “Procedures for Processing Requests to Redesignate Areas to Attainment,” September 4, 1992. John 

Calcagni, Director, Air Quality Management Division, OAQPS, USEPA. 
Floyd County PM2.5 Nonattainment Area 

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EPA made initial designations of nonattainment areas, including the Floyd County nonattainment 

area, for the 1997 annual PM2.5 NAAQS on January 5, 2005 (70FR944), and amended the 

designations on April 5, 2005 (70FR19844). The observed PM2.5 design value at Floyd County’s 

nonattainment area monitor violated the annual standard, as shown in Table 1-1 below. 

Table 1-1. PM2.5 Design Value for Floyd County 

Site Name Monitor ID PM2.5 Design Value 

2001-2003 (μg/m3) 

Rome-Coosa High School 13-115-0005 15.7 

The State of Georgia prepared and submitted a PM2.5 attainment demonstration plan for the Floyd 

County Nonattainment Area to EPA Region 4 on October 27, 2009 (cover date is October 20). The 

plan was based on modeling of the effects of existing and planned control measures on air quality in 

Floyd County and demonstrated attainment of the standard by April 5, 2010. 

Since EPA has determined that the area has met the clean data requirements (76FR 18650) and 

attained the standard prior to the attainment date (76FR 55776) (see Section 2), the SIP requirements 

that the October 27, 2009 attainment demonstration was required to fulfill are suspended. The 

attainment demonstration plan has been withdrawn and will be replaced with this maintenance plan. 

Relief from the requirement to submit an attainment demonstration as well as Reasonable Further 

Progress (RFP), associated RACM, and contingency requirements upon clean data determination is 

specified in 40 CFR 51.1004(c) and also in a December 14, 2004 memo from Stephen Page of U.S. 

EPA. 

1.2 Redesignation Request 

This document contains Georgia's request that the Floyd County nonattainment area be redesignated 

to attainment with respect to the annual NAAQS for PM2.5 (1997 fine particulate matter standard, 

retained in 2006). Section 107(d) of the CAA states that an area can be redesignated to attainment if

the following conditions are met: 

1. The EPA has determined that the NAAQS has been attained. 

2. The applicable implementation plan has been fully approved by EPA under Section 110(k). 

3. The EPA has determined that the improvement in air quality is due to permanent and 

enforceable reductions in emissions. 

4. The state has met all applicable requirements for the area under Section 110 and Part D. 

5. The EPA has fully approved a maintenance plan, including a contingency plan, for the area 

as required by CAA Section 175A. 
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The supporting documentation to show that the above conditions have been met is contained in 

Sections 2 and 3. EPA’s approval of this document will satisfy the fifth condition. 

1.3 Maintenance Plan 

The maintenance plan (see above) has two required components under Section 175A: 

• A demonstration of maintenance of the standard for at least ten years after redesignation; 

and 

• Contingency provisions for prompt correction of any future violations. 

Per EPA guidance2

, the Floyd County PM2.5 maintenance plan also includes the following elements: 

• An attainment year emissions inventory (to support the maintenance demonstration); 

• A commitment to continued operation of ambient monitoring equipment in the area; and 

• Verification of continued attainment. 

 

The maintenance plan is presented in Section 3. 

 

2

 “Procedures for Processing Requests to Redesignate Areas to Attainment,” September 4, 1992. John 

Calcagni, Director, Air Quality Management Division, OAQPS, USEPA. 
Floyd County PM2.5 Nonattainment Area 

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2.0 Redesignation Request 

As noted in Section 1.2 of this document, Section 107(d) of the CAA states that an area can be 

redesignated to attainment if the following conditions are met: 

1. The EPA has determined that the NAAQS has been attained. 

2. The applicable implementation plan has been fully approved by EPA under Section 110(k). 

3. The EPA has determined that the improvement in air quality is due to permanent and 

enforceable reductions in emissions. 

4. The state has met all applicable requirements for the area under Section 110 and Part D. 

5. The EPA has fully approved a maintenance plan, including a contingency plan, for the area 

under CAA Section 175A. 

This section of the document includes supporting documentation for the following: 

• Attainment of the annual PM2.5 NAAQS based on ambient data from 2007 through 2009; 

• Approval by EPA of the implementation plan under Section 110(k); 

• Improvement of air quality with respect to PM2.5 is due to permanent and enforceable 

reductions in emissions; and 

• The state has met all applicable requirements for the area under Section 110 and Part D. 

2.1 Attainment of the Annual PM2.5 NAAQS 

A monitoring site is in attainment of the annual PM2.5 standard when the annual standard design 

value is less than or equal to 15.0 micrograms per cubic meter (μg/m3

) per Appendix N of 40 CFR 

Part 50. The annual standard design value is the 3-year average of the annual mean, which is, in 

turn, the average of one year’s 4-calendar-quarter averages. The data must be complete and qualityassured, consistent with 40 CFR Part 58 requirements, and other relevant EPA guidance. Therefore, 

for a single site to meet the standard, the annual design value calculated from the previous three 

calendar years must be less than or equal to the standard. For a nonattainment area to achieve 

attainment, all monitoring sites in the nonattainment area must be in attainment. 

The Floyd County design value based on data from 2007 through 2009 is 13.3 μg/m3 which 

demonstrates attainment of the standard. The monitoring network and ambient PM2.5 data are 

presented below. 

2.1.1 Monitoring Network 

One PM2.5 Federal Reference Method (FRM) monitor and one PM2.5 Speciated Trends Network 

(STN) monitor were located at the Rome-Coosa High School site (13-115-0005) until March 9, 

2009. The PM2.5 FRM monitor was installed in accordance with 40 CFR 58 and had been collecting 

data since January 18, 1999 (Table 2-1). Its sampling schedule was every three days until March 1, 

2007, when it started sampling daily. The PM2.5 speciation monitor had been collecting data since 

March 3, 2002. Speciated data is useful for determining the composition of the particulate matter but

cannot be used for the purpose of determining attainment with the NAAQS. The sampling schedule 

of the PM2.5 speciation monitor was every six days. On March 10, 2009, the PM2.5 monitors at the 

Rome-Coosa High School site (13-115-0005) were relocated a short distance (less than one mile) to 

the Rome-Coosa Elementary School site (13-115-0003). PM2.5 sampling was continued from the 
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Rome-Coosa Elementary School site at the same collection frequency. The elementary school site 

did not collect PM2.5 data prior to relocation of the samplers from the high school site. 

The locations of both monitoring sites are shown in Figure 2-1. PM2.5 data collection dates at the 

sites are presented in Table 2-1. As noted above, PM2.5 sampling has been discontinued at the RomeCoosa High School site (13-115-0005). 

Figure 2-1. Locations of Floyd County PM2.5 sampling sites.
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Table 2-1. Floyd Co. PM2.5 Data Collection Sites 

Site Name AQS* 

Site ID 

Start Date – 

FRM Data 

Collection 

End Date - 

FRM Data 

Collection 

Start Date – 

Speciation 

Data 

Collection 

End Date - 

Speciation 

Data 

Collection 

Rome-Coosa 

High School 13-115-0005 Jan. 18, 1999 March 9, 2009 

March 3, 

2002 March 9, 2009 

Rome-Coosa 

Elem. School 13-115-0003 March 10, 2009 

March 10, 

2009 

* EPA’s Air Quality System 

2.1.2 Ambient PM2.5 Data 

Table 2-2 shows the annual average PM2.5 concentrations and the associated 3-year average that 

demonstrate attainment of the standard in Floyd County. The 2007 – 2009 3-year design value is 

13.3 μg/m3, which is below the standard of 15.0 μg/m3. The table includes annual averages from 

2003 through 2009, demonstrating the downward trend in the measured ambient PM2.5 level in the 

nonattainment area. The annual average PM2.5 concentration for 2010 was 13.2 μg/m3. This 

provides continued evidence that the county is meeting the standard. To date the quality-assured 

annual average for 2011 is not available. 

Table 2-2. Annual and Three-year Average Ambient PM2.5 Concentrations 

Ambient PM2.5 Concentration (μg/m3)

2003 2004 2005 2006 2007 2008 2009 2007 - 

2009 

16.2 15.6 16.6 15.9 15.7 13.0 11.3 13.3 

2.1.3 Clean Data Determination 

On April 5, 2011, EPA promulgated its determination (76 FR 18650) that the Floyd County 

nonattainment area had attained the 1997 annual average PM2.5 National Ambient Air Quality 

Standard (NAAQS). This determination was based upon quality-assured and certified ambient air 

monitoring data for the 2007-2009 period which showed a design value of 13.3 μg/m3. With the 

clean data determination, EPA suspended the requirements for the nonattainment area to submit an 

attainment demonstration, a reasonable further progress (RFP) plan, associated RACM, and 

contingency measures. These requirements are suspended as long as the area continues to attain the 

standard. This final rule became effective on May 5, 2011. 
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2.2 Implementation Plan Under Section 110(k) 

Section 110(k) of the CAA addresses EPA’s actions on state implementation plan submittals 

(completeness, deadline for action by EPA, etc.). A September 4, 1992, memo from John Calcagni 

of EPA states the following: 

“The SIP for the area must be fully approved under section 110(k), and must satisfy all requirements 

that apply to the area. It should be noted that approval action on SIP elements and the redesignation

request may occur simultaneously.” 

The State of Georgia has prepared and submitted a PM2.5 attainment demonstration plan for the 

Floyd County Nonattainment Area. The plan was submitted for approval to EPA Region 4 on 

October 27, 2009. As discussed in Section 1.1 of this redesignation request and maintenance plan, 

the attainment demonstration, associated RACM, RFP, and contingency requirements that the 

October 27, 2009 SIP revision was required to fulfill have been suspended. Therefore, the 

attainment demonstration has been withdrawn and substituted with submittal of this maintenance 

plan. There are no longer any Section 110(k) requirements to be met. 

2.3 Permanent and Enforceable and Other Reductions in Emissions 

In order for the nonattainment area to be redesignated to attainment, the State must demonstrate (and 

EPA must determine) that the improvement of ambient PM2.5 concentrations during the years 2007 

through 2009 is due to permanent and enforceable reductions, unless otherwise stated, in emissions 

that were implemented following the nonattainment design value period (2001–2003). This 

subsection contains Georgia EPD’s demonstration that the improved air quality is due to permanent 

and enforceable emissions reductions. The elements of the demonstration described below are as 

follows: 

• Source apportionment, which links individual, observed ambient PM2.5 species to 

specific emissions sources; 

• State control measures and associated emissions reductions; 

• Federal control measures and associated emissions reductions; and 

• Reductions in SO2 emissions from upwind states. 

2.3.1 Source Apportionment of Ambient PM2.5

Source apportionment of speciated ambient pollutant measurements is an important tool for the 

prioritization of pollutant control strategies. Presented here are source-apportionment results for 

2003-2004 speciated PM2.5 measurements in the Atlanta, Floyd County, and Macon areas (Figure 2-2 

and Table 2-3). The source-apportionment results are based on Positive Matrix Factorization (PMF), 

a factor analytic method that distinguishes correlation patterns among speciated PM2.5 measurements 

in a given location. More detailed information on source apportionment is presented in Appendix A. 
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The similarities between the PMF results for the three sites show the regional nature of PM2.5. The 

major impacting factors at all sites are secondary sulfates, secondary organic aerosols (SOA), mobile 

sources, and biomass burning. The Atlanta area, as expected, has higher levels of mobile-source 

PM2.5, compared to Floyd County and Macon. On the other hand, these latter two sites exhibit 

higher levels of soil dust, and the Macon site exhibits a relatively high contribution of Lime/Minerals 

PM2.5. This is likely due to local sources in the industrial area where the site is located. 

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

Atlanta Floyd county Macon

ug/m3

Unspec.

SOA

Sec. Nitrate

Sec. Sulfate

Zn-rich

Cu-rich

Road-dust

Oil burning

Na-rich

Lime/Minerals

Soil

Biomass burning

Mobile-sources

Figure 2-2: Average factor contributions for 2003-04 at the Atlanta, Floyd County, and 

Macon STN sites using PMF 

These results are useful for an assessment of control strategies. Secondary sulfate makes up 

approximately five μg/m3 (32 %) of ambient PM2.5, the largest contribution of all of the factors. 

SOAs make up the next largest contribution at 20%. The contribution of secondary nitrate is only 

one-fifth of the contribution of sulfate. Contributions from all other source-categories were small in 

general, though the Macon and Rome sites seem to be affected by local sources related to 

lime/minerals processing and soil dust re-suspension. 

Secondary sulfates are formed in the atmosphere from SO2 emissions. As the sulfate fraction is the 

largest fraction of ambient PM2.5, it is evident that controlling SO2 emissions (generated primarily by 

coal-burning EGUs) would reduce PM2.5 levels throughout the state. Secondary nitrates are 

associated with NOx emissions from combustion, primarily combustion in EGUs and in on-road 

mobile sources. SOAs are associated with biogenic emissions (natural emissions from living trees 

and other vegetation). It is not practical to control biogenic emissions. Biomass burning generates 

elemental carbon (soot) and is associated with wildfires, prescribed burning, and wood-fired boilers. 

In addition to NOx, mobile sources generate elemental carbon. 
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Table 2-3. Average factor contributions to PM2.5 (μg/m3) for 2003-04 at the Atlanta, 

Floyd County, and Macon STN sites using PMF 

Factor Atlanta Floyd County Macon 

Unspecified 2.32 2.97 1.81 

SOA 2.55 3.46 3.81 

Sec. Nitrate 0.99 1.05 0.74 

Sec. Sulfate 4.82 5.10 4.67 

Zn-rich 0.03 0.03 0.03 

Cu-rich 0.07 0.03 0.02 

Road-dust 0.12 0.13 0.11 

Oil burning 0.03 0.04 0.04 

Na-rich 0.43 0.42 0.33 

Lime/Minerals 0.05 0.24 0.59 

Soil 0.29 0.61 0.67 

Biomass burning 1.06 1.31 1.50 

Mobile sources 2.78 1.61 2.12 

2.3.2 State Control Measures - Georgia 

Based on source factor analysis, Georgia’s control strategy is focused on the reduction of emissions 

associated with secondary sulfates and nitrates, biomass burning, and mobile sources. Control of 

SO2 is the most important component of the strategy, as secondary sulfates make up the largest 

controllable contribution to ambient PM2.5. State measures that target reduction of these emissions 

are: 

• SO2 and NOx controls on EGUs [Rule (sss)]; 

• SO2 limits on EGUs [Rule (uuu)]; and 

• Smoke Management Plan. 
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Table 2-4 shows the timetable of implementation of these measures as well as the species controlled 

by each. The correlation between the drop in PM2.5 annual averages and the implementation of the 

control measures, particularly Georgia Rule 391-3-1-.02(2)(sss), lends strong evidence that the 

improvements in air quality are a result of reduction in emissions and not a meteorologicallyinfluenced phenomenon. Detailed discussions of the measures are presented in the following 

subsections. 

Table 2-4. Timetable of State Measure Implementation

Measure Species 

controlled

2001 ‘02 ‘03 ‘04 ‘05 ‘06 ‘07 ‘08 ‘09 ‘10 

PM2.5 ann. 

avg. (μg/m3), 

Floyd Co. 

 16.2 14.6 16.2 15.6 16.6 15.9 15.7 13.0 11.3 13.2 

Rule (sss) SO2, NOx * 

Smoke 

Management 

Plan 

PM, NOx 

Rule (uuu) SO2 

* Controls were required on December 31, 2008, but were actually started up in the first half of the 

year. 

2.3.2.1 SO2 and NOx

 Controls and SO2 Limits 

Atmospheric secondary sulfate is formed from emissions of SO2. Coal-fired EGUs are by far the 

most significant source of SO2 emissions in Georgia and in the Southeast. Georgia’s Multipollutant 

Rule [391-3-1-.02(2)(sss)] requires flue gas desulfurization (FGD) and selective catalytic reduction 

(SCR) controls on the majority of coal-fired EGUs in Georgia. This state-enforceable rule was 

promulgated in 2007 for the purposes of lowering ozone and PM2.5 concentrations by controlling 

precursor emissions and for reducing mercury deposition. The FGD controls reduced SO2 emissions 

rates from the affected emissions units by at least 95 percent and the SCR controls reduced NOx

emissions rates by approximately 85 percent. The SO2 and NOx controls were required in support of 

EPA’s CAIR rule, which was promulgated in 2005 and required statewide caps for NOx and SO2

beginning in 2009 and 2010, respectively. The CAIR rule is discussed further in Section 2.3.3. 

Georgia Rule (uuu), SO2 Emissions from Electric Utility Steam Generating Units, is a companion 

rule to Rule (sss) and is both state and federally enforceable upon approval. Both of these rules were 

implemented in response to CAIR and require emissions reductions consistent with CAIR’s original 

schedule starting in 2009. The rule requires 95% reduction of SO2 emissions from the majority of 

Georgia’s coal-fired EGUs, with the requirement being phased in from 2010 through 2016. All four 

EGUs at Plant Hammond are required to demonstrate 95% reduction starting on January 1, 2012. 

It has been well demonstrated that ambient secondary sulfate in a given location can be significantly 

affected by SO2 emissions from distant sources. Therefore, secondary sulfate in Floyd County is due 
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not only to SO2 emissions from Plant Hammond, located inside the county, but also to SO2 emissions 

from other coal-fired EGUs in north Georgia. Figure 2-3 shows the locations of the coal-fired EGU 

facilities in the northern half of Georgia as well as their respective energy production (in million 

megawatt-hours) in the year 2007. Plant Bowen, which is approximately 30 miles from Floyd 

County’s ambient monitor, was a close second to Plant Scherer in energy production and historically 

has been by far the highest SO2-emitting facility in the state. Plant Scherer, which was first in 

Georgia in energy production, is located approximately 120 miles from the Floyd County monitor. 

The facilities shown in the figure comprise seven of the ten coal-fired EGU facilities that were 

operated in Georgia in 2007. In 2007, the energy produced by the seven facilities made up 97 

percent of the statewide energy production from coal-fired facilities. 

Figure 2-3. Locations and 2007 Energy Production of Coal-fired EGU Facilities 

in North Georgia 
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The required FGD control implementation date varies by EGU, starting on December 31, 2008. SO2

controls were actually started on five units in May 2008. SO2 controls were operating for the entire 

year of 2009 as follows: 

• Plant Hammond – controls on 4 of 4 units; 

• Plant Bowen – controls on 2 of 4 units; and 

• Plant Wansley – controls on 1 of 2 units. 

SO2 controls on a third unit at Plant Bowen and on the second unit at Plant Wansley began operation 

on April 1, 2009. 

Rule (sss) requires SCR controls to be operated year-round, starting at six EGUs in 2008 and 2009 

(Bowen Units 2, 3, and 4; Wansley Units 1 and 2; and Hammond Unit 4). However, these NOx

controls were already in place and operating during the ozone season by the end of 2003. The Title 

V permit of each of the above facilities has been amended to permit operation of the FGD and SCR 

controls. 

Table 2-5 shows the annual SO2 emissions for Plant Hammond and the other six coal-fired facilities 

in north Georgia for the period 2003 through 2009. The table also includes the electrical generation,

a measure of production, for the facilities for the same time period. This data is presented in 

graphical form in Figures 2-4 and 2-5. 

Comparing 2003 and 2009 for Plant Hammond, SO2 emissions were reduced by 97.5% whereas 

generation was down by 22.1%. For the seven facilities, SO2 emissions were reduced by 50.4% and 

generation was down by only 4.5%. These statistics provide clear evidence that the reduction in 

PM2.5 concentration is due to permanent and enforceable controls rather than to reduced production. 
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Table 2-5. Annual SO2 Emissions and Generation (106 MWh) from North Georgia 

Coal-fired EGU Facilities, 2003 - 2009 

Facility 2003 2004 2005 2006 2007 2008 2009

Hammond SO2 (tpy) 35,900 37,700 39,500 40,600 47,800 12,500* 900*

 generation 4.79 4.11 4.64 4.27 5.09 4.32 3.73

Bowen SO2 (tpy) 164,900 165,900 186,500 206,400 196,800 148,100* 54,800*

 generation 21.9 21.9 23.3 23.7 24.0 23.4 22.9

Branch SO2 (tpy) 64,800 70,100 90,500 96,000 98,400 94,000 60,100

 generation 8.28 7.97 10.3 10.8 10.9 10.7 6.82

McDonough SO2 (tpy) 23,900 22,700 27,700 28,800 28,500 24,300 15,900

 generation 3.75 3.52 3.92 4.07 4.07 3.43 2.34

Scherer SO2 (tpy) 83,900 79,700 82,900 74,200 76,500 77,700 69,500

 generation 21.3 24.6 25.5 24.5 26.5 25.7 24.3

Wansley** SO2 (tpy) 94,000 99,000 101,500 96200 93,900 74,300* 7400*

 generation 13.7 14 15.1 14.8 16.1 15.5 11.8

Yates SO2 (tpy) 44,900 50,600 66,500 75,500 77,200 68,200 45,500

 generation 6.73 6.22 7.37 7.49 8.10 7.37 4.90

TOTAL SO2 Tons/yr 512,300 525,700 595,100 617,700 619,100 499,100 254,100

TOTAL 

Generation 106

 MWh 80.45 82.32 90.13 89.6 94.76 90.42 76.79

Ambient 

PM2.5, Floyd 

Co. 

annual 

average 

(ug/m3) 16.2 15.6 16.6 15.9 15.7 13.0 11.3

Source: EPA Clean Air Markets Division 

* SO2 control, required by Georgia Rule (sss), was operational on one or more EGUs for partial or 

full year 

** does not include emissions from facility’s gas-fired units
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0

10000

20000

30000

40000

50000

60000

2003 2004 2005 2006 2007 2008 2009

0

1

2

3

4

5

6

SO2 (tpy)

gen (million MWh)

Figure 2-4. SO2 Emissions and Generation from Plant Hammond, 2003 - 2009 

0

100000

200000

300000

400000

500000

600000

700000

2003 2004 2005 2006 2007 2008 2009

0

10

20

30

40

50

60

70

80

90

100

SO2 (tpy)

gen (million MWh)

Figure 2-5. SO2 Emissions and Generation from North Georgia 

Coal-fired EGU Facilities, 2003 - 2009 
Floyd County PM2.5 Nonattainment Area 

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2.3.2.2 Smoke Management Plan 

Forestry and agriculture, two of the Georgia’s most significant industries, utilize prescribed burning

practices to support production. Prescribed burning is the controlled application of fire to existing

vegetative fuels to accomplish planned land management objectives or to mitigate catastrophic 

wildfires. In addition to managing forests and agricultural resources, prescribed burning helps 

protect lives and property by reducing accumulations of forest fuels and helps to sustain imperiled 

species and ecosystems. The Georgia General Assembly enacted the Georgia Prescribed Burning 

Act to authorize and promote the use of prescribed burning for community protection and for 

silvicultural, environmental, and wildlife purposes. 

Large prescribed burns can produce significant PM2.5 emissions. These emissions, if not properly 

managed, can reach smoke-sensitive areas and have significant negative impacts on the air quality in 

these areas. Smoke-sensitive areas include Georgia’s heavily populated areas and PM2.5

nonattainment areas. Without a prescribed burning program, there is a higher probability of 

catastrophic wildfires, which can threaten personal property and can have even higher negative 

impacts on air quality. 

To prevent negative air quality impacts from prescribed burning, Georgia DNR and the Georgia 

Forestry Commission formulated and adopted Georgia’s Basic Smoke Management Plan (SMP) 

dated April 16, 2008. The plan was developed in accordance with EPA’s “The Interim Air Quality 

Policy on Wildland and Prescribed Fires” and the draft EPA guidance document, “Elements of a 

Smoke Management Program.” The purpose of the SMP is to allow fire to function in its natural role 

in maintaining healthy wildland ecosystems while protecting public health and welfare by mitigating 

the impacts of air pollutants from wildland and prescribed fires on air quality and visibility. The plan 

is a necessary component in determining Exceptional Events related to prescribed burning and is an 

element of Georgia’s Regional Haze SIP. The Georgia Forestry Commission (GFC), Georgia 

DNR’s EPD, and Georgia DNR’s Wildlife Resources Division (WRD) signed a Memorandum Of 

Understanding (MOU) to implement the SMP on April 16, 2008. The SMP and the MOU are 

included as Appendix B. 

The SMP identifies the following components that should be considered in the planning of 

prescribed burns: 

• smoke mitigation, 

• smoke dispersion evaluation, 

• public notification, and 

• air quality monitoring. 

Smoke mitigation, smoke dispersion evaluation, and air quality monitoring are important to 

mitigating the effects of prescribed burns on air quality in smoke-sensitive areas. Smoke mitigation 

is accomplished by avoiding smoke-sensitive areas, performing burns under favorable smoke 

dispersion conditions, and managing the generation and release of emissions over time. Smoke 

dispersion evaluations are performed by GFC-certified prescribed fire managers and are supported 

by the GFC’s full-time fire weather meteorologist. Air quality monitoring and forecasting, 

performed by Georgia EPD, provides important air quality data to assist fire managers with their 

decisions on when to schedule prescribed burns. 
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In addition to mitigating the impacts of prescribed burns on air quality, the implementation of an 

SMP has benefits with regard to the computation of air quality design values. Design values are 

statistical measures of historical ambient pollutant concentrations that are compared to EPA’s air 

quality standards to determine if attainment of the standard has been achieved. An atypical event, 

such as an unusually large forest fire, can produce PM2.5 emissions that will significantly increase 

ambient concentration measurements, and, therefore, design value computations, in a nonattainment 

area. EPA will allow the atypical ambient measurements to be excluded from the design value 

computation if the fire event is deemed to be an “exceptional event”. In order for a large fire to 

qualify as an exceptional event, the EPA has stated that a state must demonstrate that a certified SMP

was in place at the time of the event or that the state must ensure that the burner employs basic 

smoke management practices. 

All outdoor burning is subject to enforcement through law enforcement officers of GFC, DNR and 

local law enforcement. The enforcement authority is the Georgia Forest Fire Protection Act, as well 

as EPD’s authority to enforce Federal and State air quality regulations and laws. In addition, GFC 

has the authority to void certification of certified prescribed burners if investigation reveals that 

disregard for basic smoke management practices contributed to smoke intrusion into a smokesensitive area. This measure is State enforceable. It is not necessary for the continued maintenance

of attainment in the Floyd area. However, implementation of the SMP will support the maintenance 

of the annual PM2.5 NAAQS. 

2.3.3 Federal Control Measures 

Federal control measures related to ambient PM2.5 are focused on the reduction of emissions 

associated with sulfates, nitrates, and direct PM. Federal measures that targeted reduction of these 

emissions between nonattainment designation and the clean data period are as follows: 

• Clean Air Interstate Rule/Cross State Air Pollution Rule; 

• Tier 2 Vehicle Standards; 

• Heavy-Duty Gasoline and Diesel Highway Vehicles Standards and Ultra-Low Sulfur 

Diesel (ULSD) Rule; 

• Large Nonroad Diesel Engines Rule and ULSD Rule; 

• Non-Road Spark Ignition Engines and Recreational Engines Standard; and 

• NOx SIP Call in Surrounding States. 

All of the measures were in place prior to 2007, with the exception of the large nonroad diesel rule 

(effective in 2008) and CAIR. Reductions associated with vehicles and engines will increase during 

the maintenance period as older engines are removed from service and replaced by new engines. 

Table 2-6 shows the timetable of implementation of these measures as well as the species controlled 

by each. The continuous drop in PM2.5 concentration from 2005 through 2009 demonstrates that the 

improvement of air quality is due to the implementation of the control measures. Detailed 

discussions of the measures are presented in the following subsections. 
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Table 2-6. Timetable of Federal Measure Implementation 

 

Species 

controlled

2001 ‘02 ‘03 ‘04 ‘05 ‘06 ‘07 ‘08 2009

PM2.5 ann. avg. (μg/m3) 16.2 14.6 16.2 15.6 16.6 15.9 15.7 13.0 11.3 

Clean Air Interstate Rule 

(CAIR) 

NOx* 

Tier 2 vehicle standards NOx 

Heavy Duty Engine 

Standard, first phase 

NOx, 

VOC 

 

Heavy Duty Engine 

Standard, second phase, 

and ULSD 

PM, SO2 

Large Nonroad Diesel 

Rule and ULSD 

PM, NOx, 

SO2

 

Nonroad Spark Ignition 

and Recreational Vehicle 

NOx, 

VOC, CO 

 

NOx SIP Call in 

Surrounding States 

NOx 

* also requires SO2 controls after 2009 

2.3.3.1 Clean Air Interstate Rule 

On May 12, 2005, the U.S. EPA promulgated the “Rule To Reduce Interstate Transport of Fine 

Particulate Matter and Ozone (Clean Air Interstate Rule)” referred to as CAIR. This rule established 

the requirement for States to adopt rules limiting the emissions of NOx and sulfur dioxide (SO2) and 

a model rule for the states to use in developing their rules. The purpose of the CAIR was to reduce 

interstate transport of precursors to fine particulate and ozone. 

The CAIR rule applied to fossil-fuel-fired electric generation units (EGUs), including certain 

cogeneration units, with nameplate capacities of greater than 25 MWe. This rule set annual state 

caps for NOx and SO2 in two phases, with the Phase I caps starting in 2009 and 2010, respectively. 

Phase II caps for NOx and SO2 were to become effective in 2015. 

As part of the CAIR rule, EPA determined that Georgia contributed significantly to downwind PM2.5

nonattainment areas and/or interfered with maintenance of the PM2.5 NAAQS (70 FR 25246-25250). 

Accordingly, a State CAIR rule [Georgia rule 391-3-1-.02(13)] was promulgated that, for the most 

part, mirrors the provisions of the federal rule. 
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On July 11, 2008, the U.S. District Court of Appeals in the District of Columbia vacated the Clean 

Air Interstate Rule and remanded it to EPA. A rehearing of the Court’s decision was requested and 

granted. On December 23, 2008, the court remanded CAIR to EPA without vacatur (i.e., the rule 

was still in place). EPA was directed to correct the deficiencies in CAIR that were identified in the

court’s decision. 

To replace CAIR, EPA promulgated the final Cross-State Air Pollution Rule (76 FR 48208) on 

August 8, 2011. The Cross-State rule imposes restrictions on emissions of NOx and SO2 from states 

identified as having significant impacts on ozone and/or PM2.5 NAAQS attainment or as interfering 

with maintenance of these same standards in downwind states. The requirements of the Cross-state 

Rule were to become effective in 2012 and 2014 which is beyond the 2007-to-2009 clean data period 

for Floyd County. However, on December 30, 2011, the U.S. Court of Appeals for the D.C Circuit 

Court issued a ruling to stay CSAPR pending judicial review. Regardless of the timing of the 

transition from CAIR to CSAPR or the resulting court-ordered interstate transport remedy, emissions 

of NOx and SO2 have declined significantly and are expected to continue to decrease in the future 

due to the continuation of CAIR and Georgia’s own EGU emission rules. 

2.3.3.2 Tier 2 Vehicle Standards 

Federal Tier 2 vehicle standards will reduce NOx emissions from passenger vehicles. The standards 

require all passenger vehicles in a manufacturer’s fleet, including light-duty trucks and sport utility 

vehicles (SUVs), to meet an average standard of 0.07 grams of NOx per mile. Implementation began 

in 2004 and was completely phased in by 2007. The Tier 2 standards will also cover passenger 

vehicles over 8,500 pounds gross vehicle weight rating (the larger pickup trucks and SUVs), which 

are not covered by the current Tier 1 regulations. For these vehicles, the standards were phased in 

beginning in 2008 with full compliance in 2009. The new standards require vehicles to be 77% to 

95% cleaner than those on the road prior to implementation of Tier 2. The Tier 2 rule also reduced 

the sulfur content of gasoline to 30 parts per million (ppm) starting in January of 2006. Sulfur occurs 

naturally in gasoline but interferes with the operation of catalytic converters on vehicles resulting in 

higher emissions. Lower-sulfur gasoline is necessary to achieve the Tier 2 vehicle emission 

standards. 

2.3.3.3 Heavy-Duty Gasoline and Diesel Highway Vehicles Standards & Ultra Low-Sulfur Diesel 

Rule 

New U.S. EPA standards designed to reduce NOx and VOC emissions from heavy-duty gasoline and 

diesel highway vehicles (14001 pounds or more) began to take effect in 2004. A second phase of 

standards and testing procedures, which began in 2007, will reduce particulate matter from heavyduty highway engines and will also reduce highway diesel fuel sulfur content to 15 ppm to prevent 

damage to the emission control devices. The total program is expected to achieve a 90% reduction in 

particulate matter (PM) emissions and a 95% reduction in NOx emissions for these new engines 

using low sulfur diesel, compared to older engines using diesel with higher sulfur content. SO2

emissions will also be reduced due to the lower fuel sulfur content. 

2.3.3.4 Large Nonroad Diesel Engines Rule & Ultra Low-Sulfur Diesel Rule 

In May 2004, the U.S. EPA promulgated new rules for large nonroad diesel engines, such as those 

used in construction, agricultural, and industrial equipment, to be phased in between 2008 and 2014. 

The nonroad diesel rules also reduce the allowable sulfur in nonroad diesel fuel by over 99%. Prior 
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to 2006, nonroad diesel fuel averaged about 3,400 ppm sulfur. The rule limits nonroad diesel sulfur 

content to 500 ppm in 2006 and 15 ppm in 2010. The combined engine and fuel rules would reduce 

NOx and PM emissions from large nonroad diesel engines by over 90%, compared to older engines 

using diesel with higher sulfur content. SO2 emissions will also be reduced due to the lower fuel 

sulfur content. 

2.3.3.5 Nonroad Large Spark-Ignition Engines and Recreational Engines Standard 

This standard, effective in July 2003, regulates NOx, hydrocarbons (HC) and carbon monoxide (CO) 

for groups of previously-unregulated nonroad engines. The new standard applies to all new engines 

sold in the United States and imported after these standards began and apply to large spark-ignition 

engines (forklifts and airport ground service equipment), recreational vehicles (off-highway 

motorcycles and all-terrain-vehicles), and recreational marine diesel engines. The regulation varies 

based upon the type of engine or vehicle. 

The large spark-ignition engines contribute to ozone formation and ambient CO and PM levels in 

urban areas. Tier 1 of this standard was implemented in 2004 and Tier 2 started in 2007. Like the 

large spark-ignition engines, recreational vehicles contribute to ozone formation and ambient CO and 

PM levels. For the off-highway motorcycles and all-terrain-vehicles, model year 2006, the new 

exhaust emissions standard was phased-in by 50% and for model years 2007 and later at 100%. 

Recreational marine diesel engines over 37 kilowatts are used in yachts, cruisers, and other types of 

pleasure craft. Recreational marine engines contribute to ozone formation and PM levels, especially 

in marinas. Depending on the size of the engine, the standard began phasing in during 2006. 

When all of the nonroad spark-ignition engines and recreational engines standards are fully 

implemented, an overall 72% reduction in HC, 80% reduction in NOx, and 56% reduction in CO 

emissions are expected by 2020. These controls will help reduce ambient concentrations of ozone, 

CO, and fine PM. 

2.3.3.6 NOx SIP Call in Surrounding States 

In October 1998, the U.S. EPA made a finding of significant contribution of NOx emissions from 

certain states and published a rule that set ozone season NOx budgets for the purpose of reducing 

regional transport of ozone (63 FR 57356). This rule, referred to as the NOx SIP Call, called for 

ozone season controls to be put on utility and industrial boilers, as well as internal combustion 

engines in 22 states in the Eastern United States. A NOx emissions budget was set for each state and 

the states were required to develop rules that would allow the state to meet their budget. A NOx

trading program was established, allowing sources to buy credits to meet their NOx budget as 

opposed to actually installing controls. The emission budgets were to be met by the beginning of 

2004. 

2.3.4 SO2 Emissions Reductions in Upwind States 

As noted previously, secondary sulfate concentrations in a given location can be significantly 

affected by SO2 emissions from distant sources. During the period of 2003 through 2009, SO2

emissions from coal-fired electric generation facilities upwind of Georgia have been significantly 

reduced. 
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EPA promulgated the Cross-State Air Pollution Rule (76 FR 48208) on August 8, 2011, and projected 

future emissions to support the rulemaking. Modeling in support of the Cross-State Rule has 

established linkages between emissions from upwind states and ambient PM2.5 concentrations in 

downwind receptor states. EPA’s projections indicate that 2012 emissions for the base case (which 

disallows reductions from existing or future CAIR controls) from ten upwind states will contribute 

0.15 μg/m3 (1 % of the 1997 annual PM 2.5 standard) or more to ambient PM2.5 concentrations in 

Georgia’s 2012 projected nonattainment area (Atlanta). The ten states are Alabama, Illinois, Indiana,

Kentucky, North Carolina, Ohio, Pennsylvania, South Carolina, Tennessee, and West Virginia. 

[Source: Appendix D of the Air Quality Modeling Final Rule Technical Support Document, June 

2011, docket item EPA-HQ-OAR-2009-0491-4140.] 

Table 2-7 shows the SO2 emissions trends from coal-fired EGU facilities in the ten upwind states 

during the period 2003 through 2009. The total SO2 emissions from the ten states dropped 

approximately 15 percent from 2003 to 2007 and over 50 percent from 2003 to 2009. The trend of 

aggregated SO2 emissions from these states is presented in Figure 2-6. 
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Table 2-7. Annual SO2 Emissions in States With Downwind Contributions to Georgia 

PM2.5 Exceeding 0.15 μg/m3

State 2003 2005 2007 2009 

AL 458,622 460,072 447,189 277,972

IL 365,333 326,632 272,571 229,364

IN 804,829 870,812 714,529 413,726

KY 529,559 500,224 379,837 252,002

NC 462,041 500,936 370,826 110,948

OH 1,175,905 1,085,485 954,646 600,687

PA 967,185 985,508 951,186 573,618

SC 203,956 217,386 172,726 97,941

TN 339,536 266,081 237,231 108,042

WV 539,858 467,082 371,996 174,583

TOTAL 5,846,824 5,680,218 4,872,738 2,838,883

Source: EPA Clean Air Markets Division, Acid Rain Program 

EPD understands that the emissions reductions in the upwind states are not permanent and 

enforceable reductions in Georgia. However, we believe that the reductions provide further evidence 

that the reduced PM2.5 levels in Georgia during the period 2007-2009 are due to SO2 emissions 

reductions achieved both within and outside Georgia. The majority of upwind reductions are due to 

state rules or consent orders requiring reduced SO2 emissions. With the promulgation of the CrossState Air Pollution Rule, it is highly unlikely that these reductions will be reversed in the future. (It 

should be noted that on December 30, 2011, the U.S. Court of Appeals for the D.C Circuit Court 

issued a ruling to stay CSAPR pending judicial review. Regardless of the timing of the transition 

from CAIR to CSAPR, or the resulting court-ordered interstate transport remedy, emissions of SO2

from upwind states have declined significantly and are expected to continue to decrease in the 

future.)
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0

1,000,000

2,000,000

3,000,000

4,000,000

5,000,000

6,000,000

7,000,000

2003 2005 2007 2009

SO2 (tons)

Upwind States

Figure 2-6. Trend of Aggregated Annual SO2 Emissions in States With Downwind 

Contributions to Georgia PM2.5 Exceeding 0.15 μg/m3

2.4 Section 110 and Part D Requirements 

Section 110 of the CAA contains the requirements for state implementation plans (SIPs). The 

purpose of a SIP is to provide for the implementation, maintenance, and enforcement of national 

primary ambient air quality standards. Part D, Subpart 1, of CAA Title I (Sections 171 to 179) 

contains general requirements for areas that have been designated nonattainment. As stated in 

Section 1.1 of this maintenance plan, Floyd County was designated as nonattainment for the 1997 

annual fine PM standard in April of 2005. The county is not now and has not previously been 

designated nonattainment for any other NAAQS. 

Georgia EPD submitted a PM2.5 nonattainment plan for Floyd County per Title I Part D. With the 

determination that the Floyd County nonattainment area has attained the 1997 annual fine PM 

standard (Section 2.1.3), the area is no longer subject to the nonattainment provision of CAA Section 

110 and Part D requirements for demonstrating attainment, RFP, associated RACM, and contingency 

for areas designated as nonattainment with the NAAQS. Therefore, the nonattainment plan was 

subsequently withdrawn. All other Section 110 and Part D requirements pertaining to the Floyd 

County area have previously been approved or are currently subject to approval by EPA. 
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3.0 Maintenance Plan 

Section 175A of the Clean Air Act Amendments of 1990 defines the general framework of a 

maintenance plan. The core provisions of Section 175A are a quantitative demonstration of 

maintenance of the standard (PM2.5 in this case) and contingency provisions for prompt adoption of 

corrective measures if attainment is not maintained. Per guidance from EPA,3 this maintenance plan 

includes a method to verify continued attainment to support the maintenance demonstration. Per the 

same guidance, this plan also includes a plan to use the ambient monitoring network for verification 

of continued attainment or, if applicable, for triggering contingency provisions. 

3.1 Maintenance Demonstration 

Section 175A of the CAA requires a state that is requesting redesignation to submit a revision to its 

SIP which provides for maintenance of the applicable standard for a minimum of 10 years after the 

redesignation date. Section 107(d)(3)(D) provides EPA up to 18 months from receipt of a complete 

submittal to process a redesignation request. Therefore, Georgia EPD is providing a demonstration 

of maintenance through the year 2023. 

There are two generally-accepted methodologies for demonstrating maintenance. Under the first 

method, an emissions inventory is compiled for one of the three years which are used to show clean 

(i.e., attaining) ambient data (see Section 2.1). This year is the baseline or attainment year. 

Emissions projections are formulated for the final year of the maintenance period and for 

intermediate years. If each of the projected emission levels is less than the emission level for the 

attainment year, maintenance of the standard is demonstrated. This assumes that ambient 

concentrations will remain below the standard if future annual emissions are kept below the 

inventoried emissions in the chosen attainment year. Under the second maintenance demonstration 

method, air quality modeling is used to project ambient pollutant concentrations and annual design 

values for the final year and intermediate years. If all of the modeled, rolling, 3-year averages of the 

annual design values are below the standard, maintenance is demonstrated. 

Georgia EPD has adopted the method of comparing attainment year emissions to projected emissions 

for this maintenance plan. This approach has been used in the previous maintenance plans submitted 

by EPD and approved by EPA. The following sections discuss the attainment year inventory, the 

projected inventories, and verification of continued attainment. 

 

3

 “Procedures for Processing Requests to Redesignate Areas to Attainment,” September 4, 1992. John 

Calcagni, Director, Air Quality Management Division, OAQPS, USEPA. 
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3.1.1 Attainment Year Emissions Inventory 

Georgia EPD has selected 2007 as the year for the attainment year emissions inventory. 2007 is one 

of the three years (2007–2009) on which Floyd County’s clean data determination is based. The 

pollutants inventoried and addressed in this maintenance plan are direct PM2.5, SO2, and NOx. The 

following emissions sectors are included in the inventory: 

• Point sources (EGU and non-EGU). 

• Nonpoint sources (including fire), 

• Onroad mobile sources, and 

• Nonroad mobile sources (including marine vessels, aircraft, and rail). 

The 2007 inventory, with the exception of on-road mobile emissions, was prepared for Georgia by 

the contractors for the Southeastern Modeling, Analysis, and Planning (SEMAP) project. SEMAP is 

funded by the same ten states that participated in the Visibility Improvement – State and Tribal 

Association of the Southeast (VISTAS) project. Under the SEMAP project, emissions estimates are 

reported by county and source classification code (SCC). The SEMAP emissions inventories were 

developed using data from a number of sources, including state and local agencies and EPA’s 

National Emissions Inventory (NEI). Georgia EPD developed in-house the 2007 inventory of onroad mobile emissions. 

The data sources for the attainment-year emissions inventories are summarized in Table 3-1. 

Additional details on the data sources and inventory methods are presented in the following 

subsections and in Appendix C. 

Table 3-1. 2007 Emissions Inventory Sources 

Emissions Source 

Sector 

Inventory Source Version / Year 

Generated 

Basis 

Point – EGU SEMAP 

Georgia Power Co. 

Version 1.8, 2011 EPA’s NEI 

Point – non-EGU SEMAP Version 1.8, 2011 EPA’s NEI 

Nonpoint SEMAP Version 1.1, 2010 EPA’s NEI 

Onroad Mobile GDOT 2011 Georgia DOT [travel demand 

model and Highway 

Performance Monitoring 

System (HPMS)] and 

MOVES2010a 

Nonroad Mobile SEMAP Final Report, 2010 NMIM2008, 2007 NMIM 

County Database, 2008 NEI, 

ERTAC 
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3.1.1.1 Point Sources 

Point sources captured in the inventory include stationary sources whose actual emissions equal or 

exceed 100 tons per year of SO2, NOx, or particulate matter. Emissions from point sources have been 

calculated for EGU and non-EGU sources. 

Plant Hammond, which includes four EGUs, is the lone electric generation facility inside the 

nonattainment area. The non-EGU point sources in Floyd County are as follows: 

• Temple–Inland Rome Lumber Mill, 

• Temple–Inland Rome Linerboard Mill, 

• Metal Container Corporation, 

• Packaging Products Corporation, and 

• General Shale Brick Plant 40. 

2007 emissions of SO2, NOx, and PM2.5 from EGU and non-EGU facilities are presented in Table 3-

2. The Temple–Inland Rome Linerboard Mill is by far the largest source of emissions from nonEGU point sources. Emissions from the individual non-EGU point sources are shown in Table 3-3. 

Table 3-2. Point Source Emissions for 2007 (tons, annual) 

Pollutant EGU (Plant 

Hammond) 

Non-EGU Total Point 

SO2 47,809 3,466.6 51,275

NOx 7,558 2,607.0 10,165

PM2.5 572 380.6 953

Table 3-3. Non-EGU Point Source Emissions for 2007 (tons, annual) 

Pollutant T-I Rome

Lumber 

T-I Rome 

Linerboard 

Metal 

Container

Packaging

Products 

Gen. Shale

Br. Plt. 40 

SO2 0.0 3337.5 0.1 0.0 129.0

NOx 0.0 2591.2 13.4 2.5 0.0

PM2.5 0.0 379.1 1.3 0.2 0.0

The 2007 point source inventory is based on the National Emissions Inventory (NEI) reports for 

reporting years 2005, 2007, and 2008. Emissions from sources that reported for 2007 were generally 
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used as reported. For facilities with 2005 and 2008 emissions (but no 2007 emissions), 2007 

emissions were estimated based on a linear interpolation between facility level 2005 and 2008 

emissions on a pollutant-by-pollutant basis to calculate facility-level 2007 emissions. For facilities 

with only 2008 data (no 2007 or 2005 data available), the SIC growth factors from the VISTAS Best 

& Final inventory were used to backcast 2008 reported emissions to 2007. For facilities with only 

2005 data (no 2007 or 2008 data available), the SIC growth factors from the VISTAS Best & Final 

inventory were used to project 2005 reported emissions to 2007. After the above backcasting and 

projecting was performed, additional adjustments were made for facilities where only 2005 data 

were available and the facility did not operate in 2007 or operated for only part of 2007. In addition, 

PM augmentation was performed to generate missing emissions estimates for filterable and primary 

PM2.5, filterable and primary PM10, and condensable PM. See Appendices C and C-1 for more 

details on the development of the 2007 point source emissions inventory. 

3.1.1.2 Nonpoint Sources 

Nonpoint sources captured in the inventory include stationary sources whose emissions levels of 

SO2, NOx, and particulate matter are each less than 100 tons per year. Emissions from nonpoint 

sources in 2007 were obtained from the SEMAP nonpoint source inventory Version 1.1, which was 

developed by Pechan. A default 2007 nonpoint source inventory was created that includes all of the 

source categories covered by the 2008 nonpoint source NEI. 

For all source categories except industrial and commercial/institutional (ICI) fuel combustion, 

emissions data from the 2008 nonpoint source NEI were directly incorporated when the NEI 

emissions were based on 2007 emissions activity data. The NEI emissions estimates were 

recalculated to reflect 2007 activity levels when the NEI emissions reflected 2006 or 2008 activity 

levels. Emissions associated with activity reflected in the point source inventory were removed from 

the nonpoint inventory. 

For ICI fuel combustion, the 2008 nonpoint source NEI developed emissions activity estimates 

rather than emission estimates. Because of the potential importance of these source categories and 

the availability of methodological improvements, Pechan utilized an emissions estimation method 

for ICI fuel combustion that incorporates a few refinements to the NEI method. These emissions 

were supplemented with carry-forward categories from Georgia’s 2005 CERR submission grown 

using EPA’s Economic Growth Analysis System (EGAS). For more information regarding the 

SEMAP nonpoint inventory, please refer to Appendices C and C-2. 

The 2007 nonpoint source emissions for Floyd County are presented in Table 3-4. The largest 

contributors to SO2 emissions were coal-fired and residual-oil-fired industrial boilers. The largest 

contributors to NOx emissions were industrial wood-fired and coal-fired boilers. The largest 

contributors to PM2.5 emissions were industrial wood-fired boilers and road dust from unpaved roads. 

Emissions from fires in 2007 were obtained from the SEMAP final “actual” fire emissions inventory 

and are shown in Table 3-4. This inventory was developed using 2007 burned area data submitted by 

Georgia, as well as updated fuel consumption and emissions factors. 
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Table 3-4. Nonpoint Source Emissions for 2007 (tons, annual) 

Pollutant Nonpoint 

(excluding fire) 

Fire Total 

Nonpoint

SO2 743 16 758

NOx 877 59 936

PM2.5 1645 210 1855

The 2007 level of PM2.5 emissions from nonpoint sources, excluding fire, was 1645 tons. This 

quantity accounted for over 50 percent of total PM2.5 emissions in Floyd County. The top three 

nonpoint source classifications for PM2.5 emissions were industrial wood-fired boilers, dust from 

unpaved roads, and residential open burning of household waste (see Table 3-5). 

Table 3-5. Largest Nonpoint PM2.5 Emissions by Source Classification 

SCC Description 2007 PM2.5

(tons) 

2102008000 Stationary Fuel Comb /Industrial /Wood /Total: 

All Boiler Types 

797

2296000000 Unpaved Roads /All Unpaved Roads /Total:

Fugitives 

438

2610030000 Open Burning /Residential /Household Waste 103

3.1.1.3 Onroad Mobile Sources 

U.S. EPA’s MOVES2010a mobile source emissions model was run in inventory mode to generate 

2007 on-road mobile source emissions of SO2, NOx, and PM2.5. The 2007 onroad mobile source 

emissions for Floyd County are presented in Table 3-6. 
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Table 3-6. Onroad Mobile Source Emissions for 2007 (tons, annual) 

Pollutant Onroad 

Emissions 

SO2 14

NOx 3378

PM2.5 117

The following non-default inputs to the MOVES model were used: 

• registration distribution by age, 

• vehicle population, 

• vehicle miles traveled (VMT), and 

• hourly temperature and relative humidity. 

The age distribution and vehicle population inputs were based on 2002 vehicle counts by MOBILE6 

vehicle type obtained from R.L. Polk & Company. The vehicle population was grown to 2007 using 

a combination of Georgia Department of Revenue registration data (for buses and motorcycles) and 

the change in person population estimates from the U.S. Census (for the other MOBILE6 vehicle 

types). VMT fractions were based on MOVES defaults by source type and adjusted using GDOT 

count data. 

Actual 2007 temperature and humidity data extracted from the "NCD20090531" version of the 

county database in EPA's National Mobile Inventory Model were used as meteorological inputs to 

MOVES2010a for 2007. For a detailed discussion on how the on-road mobile emission inventory 

was developed, see Appendices C, C-3, and C-4. 

3.1.1.4 Nonroad Mobile Sources 

The nonroad sector is comprised of nonroad engines included in EPA’s NONROAD model, such as 

recreational marine and land-based vehicles, farm, construction and industrial machinery, and lawn 

and garden equipment. This sector also includes engines not modeled in NONROAD, specifically 

aircraft, commercial marine vessels, and locomotives. There are no commercial marine vessel 

emissions sources in Floyd County. 2007 nonroad mobile emissions are presented in Table 3-7. 

Emissions from NONROAD model source categories in 2007 were obtained from the SEMAP final 

nonroad mobile sources emissions inventory. These emissions were calculated using EPA’s latest 

National Mobile Inventory Model, NMIM2008, which incorporates EPA’s latest NONROAD model 

(NONROAD2008) and reflects all of EPA’s final nonroad standards to date. The county/monthly 

gasoline profile assignments in the County/Year/Month table and the gasoline fuel profiles in the 

Gasoline table of the 2007 NMIM county-level database (NCD) were updated with data provided by 

the state of Georgia. For more information regarding the SEMAP nonroad inventory, please refer to 

Appendices C and C-2. 2007 Emissions from aircraft and locomotives were obtained from the 
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SEMAP final nonroad mobile source emissions inventory. For more information regarding the 

SEMAP marine, aircraft, and locomotives inventory, please refer to Appendices C and C-5. 

Table 3-7. Nonroad Mobile Source Emissions for 2007 (tons, annual) 

Pollutant 

(tons) 

Nonroad - 

except air and 

rail

Aircraft Locomotive Total 

Nonroad

SO2 22.5 0.1 6.4 29

NOx 419.7 0.8 575.0 996

PM2.5 43.8 2.1 19.9 66

3.1.1.5 Summary of 2007 Emissions Inventory 

The total 2007 Floyd County emissions of SO2, NOx, and PM2.5 are presented for each source sector 

in Table 3-8. The majority of SO2 emissions, by far, are from point sources. The majority of NOx

emissions is from point and onroad mobile sources. The majority of PM2.5 emissions are from 

nonpoint and point sources. 

Table 3-8. Attainment-year (2007) Emissions Inventory (tons, annual)

Pollutant

(tons) 

Point 

Total 

Point 

EGU 

Point 

NonEGU 

Nonpoint Onroad 

Mobile 

Nonroad 

Mobile 

Total 

SO2 51,275 47,809 3,467 758 14 29 52,077

NOx 10,165 7,558 2,607 936 3,378 996 15,475

PM2.5 953 572 381 1,855 117 66 2991

3.1.2 Projected Emissions Inventories 

As discussed previously, Georgia EPD is providing a demonstration of maintenance through the year 

2023 (the maintenance year). Emissions projections to support maintenance through 2023 have been 

prepared for the years 2017 and 2023. In addition, emissions have been calculated by interpolation 

for the years 2014 and 2020. Emissions for these additional years provide additional reference 

points for periodic assessment of maintenance of the standard. Maintenance period emissions 

controls, projection methods, and projected inventories are discussed in the remainder of this 

subsection. 

3.1.2.1 Methods and Projected Inventories 

Projected emissions inventories are calculated by applying applicable control and growth factors to 

the 2007 emissions of individual sources or source categories. The control and growth factors may 
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apply for some or all of the years 2008 (year following attainment inventory) through 2023 (out 

year). The bases used to determine these factors are summarized in Table 3-9. 

Table 3-9. Bases of Control and Growth Factors for 2017 and 2023 Inventories 

Source 

Category 

Control Basis Growth Factor Basis 

Point – EGU Implementation of GA rule (sss) 

for SO2 and NOx controls; VISTAS 

2012 projection inventory 

Coal consumption forecasts in 2010 

Annual Energy Outlook (AEO) 

Point – non-EGU Regulatory review - no additional 

controls defined at this time 

EGAS growth factors by SCC and county 

for 2017 and 2023. 

Nonpoint Regulatory review - no additional 

controls defined at this time 

EGAS growth factors by SCC for 2017 

and 2023. 

Nonpoint – fire No additional controls anticipated No growth anticipated 

Onroad Mobile MOVES inventory mode (PM2.5, 

NOx, SO2) for 2023. All known 

Federal controls. 

MOVES inventory mode (PM2.5, NOx, 

SO2) for 2023. Vehicle population growth 

from human population projections. 

Vehicle miles traveled (VMT) growth 

from Georgia DOT. 

Nonroad Mobile NMIM 2008 NMIM 2008 

Nonroad Mobile 

– marine, 

aircraft, and rail 

SEMAP (Pechan) control factors 

by SCC for 2017 and 2023 

SEMAP (Pechan) growth factors by SCC 

for 2017 and 2023 

The pollutants whose emissions are projected are SO2, NOx, and direct PM2.5. As with the attainment 

inventory, emissions from the following sectors are projected: 

• Point sources (EGU and non-EGU). 

• Nonpoint sources (including fire). 

• Onroad mobile sources. 

• Nonroad mobile sources (including marine vessels, aircraft, and rail). 

The projected inventories are presented in the following subsections. The methods used to develop 

the emissions projections are presented in more detail in Appendix C. 
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3.1.2.2 Point Sources 

EGU point source emissions in 2017 and 2023 were estimated using growth factors and control 

factors. Growth factors were calculated based on coal consumption for the southeastern region in the 

Energy Information Administration’s AEO2010 report. The SO2 control factor due to Flue Gas 

Desulfurization (FGD) was assumed to be 95% according to the VISTAS 2012 Projection Emissions 

Inventory (see Appendices C and C-6). Georgia’s Rule (sss) requires SO2 controls on all four of 

Plant Hammond’s EGUs on December 31, 2008. The SO2 controls on the four EGUs at Plant 

Hammond will be operating at all times going forward from 2009, whereas the controls were 

operated for only 55 percent of the 3-year attainment period (36 months from 2007 through 2009). 

In addition, Georgia Rule (uuu) requires 95% reduction of SO2 for all four of Plant Hammond’s 

EGUs beginning January 1, 2012. The NOx control factor due to Selective Catalytic Reduction 

(SCR) was assumed to be 82.5% according to the VISTAS 2012 Projection Emissions Inventory. 

Georgia’s Rule (sss) requires NOx control, with a year-round operation date of December 31, 2008, 

on only one (Unit 4) of Hammond’s four units. The PM2.5 control factor associated (as a co-benefit) 

with the new SO2 controls was assumed to be 50% based on Table 5.4-1 on page 5.4-24 of EPA’s 

document "Stationary Source Control Techniques Document for Fine Particulate Matter" (EC/R 

Incorporated, 1998). 

As noted in subsection 2.3.3, EPA promulgated CSAPR in 2011 but the rule was stayed later in the 

year. When the rule was promulgated, Georgia was identified as a covered state and, therefore, 

would have been required to comply with statewide allocations of SO2 and/or NOx emissions from 

covered EGUs starting in 2012. The future of the rule is not known at this time and, therefore, the 

rule’s requirements have not been incorporated into the emissions projections presented here. Any 

further reductions that may ultimately be required by the Cross-State Rule will only strengthen the 

case for maintenance of the NAAQS as documented in this plan. 

Projected EGU point source emissions are presented in Table 3-10. The projections show a dramatic 

reduction in SO2 emissions as well as significant reductions in NOx and PM2.5 emissions. Emissions 

levels for 2014 were calculated by linear interpolation between 2007 and 2017. Emissions levels for 

2020 were calculated by linear interpolation between 2017 and 2023. 
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Table 3-10. Projected Point Source Emissions (tons) 

Pollutant 2007 

(attainment)

2014 2017 2020 2023 

 

EGU 

SO2 47,809 16,038 2,422 2,466 2,509

NOx 7,558 5,526 4,655 4,738 4,821

PM2.5 572 375 290 295 300

Non-EGU 

SO2 3,467 3,627 3,696 3,777 3,857

NOx 2,607 2,741 2,798 2,922 3,045

PM2.5 381 399 407 427 446

Total Point 

SO2 51,275 19,666 6,119 6,242 6,366

NOx 10,165 8,267 7,453 7,660 7,866

PM2.5 953 774 697 722 747

Projected non-EGU point source emissions are shown in Table 3-10 (county totals) and in Table 3-11 

(by facility, 2023 only). The emissions for 2017 and 2023 were estimated using SCC-specific and 

county-specific growth factors generated with EPA’s Economic Growth Analysis System version 5.0 

(EGAS 5.0). Appendix C-7 contains the SCC-specific growth factors for Floyd County. The 

projections show moderate increases in emissions of all three pollutants. No additional future 

controls can be defined for non-EGU point sources at this time. Emissions levels for 2014 and 2020 

were calculated by interpolation as described above. 

Table 3-11. Non-EGU Point Source Emissions for 2023 (tons, annual) 

Pollutant T-I Rome

Lumber 

T-I Rome 

Linerboard

Metal 

Container

Packaging

Products 

Gen. Shale 

Brick Plt. 40 

SO2 0.0 3675.3 0.1 0.0 181.9

NOx 0.0 3025.8 16.2 3.0 0.0

PM2.5 0.0 444.4 1.8 0.2 0.0

Projected total point source emissions (sum of EGU and non-EGU) are shown in Table 3-10. The 

projections show dramatic decreases in emissions of SO2 as well as moderate decreases in emissions 

of NOx and PM2.5. 
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3.1.2.3 Nonpoint Sources 

Nonpoint source emissions, excluding fire, in future years 2017 and 2023 were estimated using SCCand county-specific growth factors generated with EGAS 5.0. Appendix C-7 contains the SCCspecific growth factors for Floyd County. No additional future controls can be defined for these 

sources at this time. 

Projections of nonpoint source emissions are presented in Table 3-12. Emissions from fire in future 

years 2017 and 2023 were assumed to be the same as 2007 emissions. The projections show a small 

increase in emissions of SO2 as well as moderate increases in emissions of NOx and PM2.5. 

Table 3-12. Projected Nonpoint Source Emissions (tons) 

Pollutant 2007 

(attainment)

2014 2017 2020 2023 

 

Nonpoint 

(excluding fire) 

 

SO2 743 768 779 791 803

NOx 877 967 1,006 1,045 1,084

PM2.5 1,645 1,862 1,954 2,039 2,123

Fire 

SO2 16 16 16 16 16

NOx 59 59 59 59 59

PM2.5 210 210 210 210 210

Total Nonpoint 

SO2 758 784 794 807 819

NOx 936 1,026 1,066 1,104 1,144

PM2.5 1,855 2,072 2,164 2,249 2,333

The top three nonpoint source classifications for 2023 PM2.5 emissions are industrial wood-fired 

boilers, dust from unpaved roads, and residential open burning of household waste (see Table 3-13). 

Projected PM2.5 emissions from these three source classifications make up over 70 percent of total 

projected PM2.5 emissions. 
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Table 3-13. Largest Nonpoint PM2.5 Emissions by Source Classification, Year 2023 

SCC Description 2023 PM2.5

(tons) 

2102008000 Stationary Fuel Comb /Industrial /Wood /Total: 

All Boiler Types 

1044

2296000000 Unpaved Roads /All Unpaved Roads /Total:

Fugitives 

567

2610030000 Open Burning /Residential /Household Waste 133

3.1.2.4 Onroad Mobile Sources 

EPD ran U.S. EPA’s MOVES2010a mobile source emissions model in inventory mode to generate 

2023 onroad mobile source emissions of SO2, NOx, and PM2.5. Intermediate-year emissions were 

generated by interpolating between 2007 and 2023. The following non-default inputs to the model 

were used: 

• Vehicle age distribution, 

• average speed distribution, 

• vehicle population. 

• vehicle miles traveled (VMT), 

• road type distribution, 

• ramp fraction, and 

• hourly temperature and relative humidity. 

The vehicle age distribution was based on R.L. Polk & Co. registration data. MOVES defaults were 

used for Heavy-Duty Diesel Vehicle Class 8B. Person population growth projections for the Floyd 

County Metropolitan Planning Organization (MPO) area were used to calculate the 2023 vehicle 

population. The 2023 annual VMT were calculated by Georgia DOT using travel demand model 

outputs and HPMS counts, as well as speed distribution, road type distribution, and ramp fraction. 

Temperature and humidity inputs were assumed to be the same as year 2007. 

The projected onroad mobile source emissions levels are presented in Table 3-14. Onroad emissions 

of all three pollutants trend downward significantly during the maintenance period. The trend in SO2

is of less importance since onroad mobile sources emit very little SO2. For a detailed discussion on 

how the onroad mobile emission inventory was developed, see Appendices C, C-3, and C-4. 
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Table 3-14. Projected Onroad Mobile Source Emissions (tons) 

Pollutant 

(tons) 

2007 

(attainment)

2014 2017 2020 2023 

 

SO2 14.1 11.6 10.5 9.4 8.3

NOx 3378.3 2270.9 1796.2 1321.6 847.0

PM2.5 117.3 79.9 63.9 47.8 31.8

3.1.2.5 Nonroad Mobile Sources 

Projections of nonroad emissions in 2017 and 2023, excluding air and rail sources, were calculated 

using NMIM2008 with the same meteorological inputs as for 2007. Defaults in NMIM 2008 were 

used for other inputs. 

Growth factors for all aircraft engine and airport-related SCCs were based on landing and take-off 

operation (LTO) projections available from the Federal Aviation Administration’s Terminal Area 

Forecasts (FAA, 2010). Growth rates for military aircraft were held constant at 2007 levels. No 

control factors were applied to aircraft emissions.

Growth factors for freight rail sector emissions were based on fuel consumption forecasts. For 

passenger and commuter rail, growth factors were developed from national forecasts of intercity rail 

diesel consumption and commuter rail diesel consumption. Control factors were based on U.S. 

EPA’s locomotive engine regulatory impact analysis and associated emission factor guidance. 

The nonroad mobile source emissions projections are presented in Table 3-15. Total emissions of all 

three pollutants trend downward significantly during the maintenance period. As with onroad 

sources, the downward trend in SO2 is of less importance since nonroad sources emit very little SO2. 

For a detailed discussion on how the nonroad mobile emissions projections were developed, see 

Appendix C. 

 
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Table 3-15. Projected Nonroad Mobile Source Emissions (tons) 

Pollutant 

(tons) 

2007 

(attainment) 

2014* 2017 2020* 2023 

Nonroad** 

SO2 22.5 0.6 0.7

NOx 419.7 223.0 170.5

PM2.5 43.8 28.6 22.0

 

Aircraft 

SO2 0.1 0.1 0.1

NOx 0.8 0.8 0.8

PM2.5 2.1 1.9 1.9

 

Locomotive 

SO2 6.4 0.3 0.3

NOx 575.0 389.1 307.9

PM2.5 19.9 9.7 6.9

 

Tot. Nonroad 

SO2 29 9 1 1 1

NOx 996 728 613 546 479

PM2.5 66 48 40 36 31

* interpolation to 2014 and 2020 performed only for total nonroad emissions 

** excluding aircraft and locomotive emissions 

3.1.3 Emissions Projections Summary and Demonstration of Maintenance of Attainment 

The consolidated emissions projections for all Floyd County sources are presented in Table 3-16. 

Emissions of SO2 and NOx drop significantly from 2007 to 2023. This is a reflection of the 

implementation of the majority of state and federal controls during the first half of the maintenance 

period. Overall, emissions of SO2 and NOx are projected to decline by 86 percent and 33 percent, 

respectively, over the course of the maintenance period. 

Emissions of PM2.5 are flat from 2007 to 2017 and rise slightly from 2017 through 2023. This is a 

reflection of an increase in nonpoint source emissions (primarily industrial wood boilers and road 

dust) which is partially offset by reductions in the point and mobile sectors. The overall rise in PM2.5

is 5.0 percent of attainment year emissions. Therefore, further evaluation is needed to judge whether

the increase in PM2.5 emissions, in combination with the decreases in SO2 and NOx emissions, is 

likely to provide for maintenance of the standard. 
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Table 3-16. Projected Emissions – Total of All Sectors (tons) 

Pollutant 

(tons) 

2007 

(attainment)

2014 2017 2020 2023 % change, 

2007 - 2023 

 

SO2 52,077 20,471 6,925 7,060 7,194 - 86.2

NOx 15,475 12,292 10,928 10,632 10,336 - 33.2

PM2.5 2,991 2,973 2,965 3,054 3,142 + 5.0

Each of the three pollutants is characterized by a different relationship between emissions and air 

quality. Therefore, simply summing the emissions of the pollutants does not provide a meaningful 

indicator of the combined air quality impact of these emission changes. A more appropriate indicator 

is the percentage change in emissions for each emitted pollutant, weighted according to the air 

quality impact for each. 

For this purpose, Georgia EPD examined PM2.5 speciation data available from the EPA Air Explorer 

Web site for 2007-2009 for the Floyd County monitor (see Table 3-17). The 3-year average of this 

data suggests that ambient PM2.5 in Floyd County consists of approximately 45.2 percent sulfate, 1.9 

percent nitrate, 45.3 percent organic particulate (which consists of directly-emitted primary organic 

matter and atmospherically formed secondary organic aerosol), 4.0 percent miscellaneous inorganic 

particulate (sometimes labeled ‘‘crustal particles’’), and 3.6 percent other types of particulate matter. 

Therefore, using a conservative assumption that all of the organic particulate is primary organic 

matter, direct PM2.5 species make up 49.3 percent (sum of 45.3 and 4.0) of the total ambient PM2.5. 

Table 3-17. PM2.5 Speciation Data 

Site and Year sulfate 

(μg/m3) 

nitrate 

(μg/m3) 

organic 

particulate

(μg/m3) 

crustal 

(μg/m3) 

other 

(μg/m3) 

Total 

(μg/m3) 

Rome-Coosa HS

2007 

8.17 0.33 7.55 0.57 0.49 17.10 

Rome-Coosa HS

2008 

6.45 0.22 5.85 0.45 0.50 13.46 

Rome-Coosa ES

2009 

3.96 0.22 5.21 0.65 0.50 10.54 

 

Average 6.2 0.3 6.2 0.6 0.5 13.7 

Percent of Total 45.2 1.9 45.3 4.0 3.6 100.0 

Georgia EPD used a conservative approach that assumes that the full ambient concentration of 

organic particulate matter plus miscellaneous inorganic particulate matter will vary in accordance 

with changes in total nonattainment area emissions of direct PM2.5. This analysis thus assumes that 

the direct PM2.5 component of ambient PM2.5 will increase by the 5.0 percent projected increase in 

direct PM2.5 emissions. This approach was used by U.S. EPA in its evaluation and approval of the 

annual PM2.5 redesignation request for the Evansville, Indiana, nonattainment area (see 76 FR 29695 

and 76 FR 59527). 
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In the Floyd County analysis, the baseline concentration is conservatively assumed to be 15.0 μg/m3

. 

Direct PM2.5 is estimated to contribute 49.3 percent, or 7.4 μg/m3, of the 15.0 μg/m3. Georgia EPD’s 

assessment assumes that the projected increase in direct PM2.5 emissions will cause a corresponding 

5.0 percent increase in ambient concentrations of PM2.5, which would suggest an increase in the 

ambient concentration of the direct PM2.5 component by 0.37 μg/m3. 

However, Georgia EPD believes that this potential increase will be fully offset by a greater decrease 

in sulfate and nitrate concentrations. The precise decrease in sulfate and nitrate concentrations is a 

complicated result of emissions reductions not just in Floyd County, but also in many other parts of 

the Eastern United States. Nevertheless, modeling conducted by EPA for the Cross State Air 

Pollution Rule (CSAPR) estimated that future Floyd County concentrations with the final CSAPR in 

place would be 3.0 μg/m3

 below the standard (2014 Remedy Average case*). In addition, the 

emissions reductions that have already occurred have brought measured Floyd County 

concentrations to 13.3 μg/m3

 (as shown in Table 2-2). Therefore, the 0.37 μg/m3 increase in the 

components associated with direct PM2.5 would not be expected to yield concentrations above the 

standard. That is, GA EPD believes that maintenance of the annual PM2.5 standard is demonstrated 

despite the small projected increase in direct PM2.5 emissions. 

* Air Quality Modeling Final Transport Rule Technical Support Document, docket item EPA-HQOAR-2009-0491-4140 

3.1.4 Emissions Decreases 

An emissions surplus represents the degree of improvement (reduction) in 2023 emissions compared 

to the attainment year (2007) emissions. The surpluses are shown in Table 3-18 for each pollutant. 

A positive surplus reflects an emissions decrease from the attainment year to 2023. The negative 

surplus for PM2.5 reflects a projected increase in emissions. A portions of the NOx surplus will be 

allotted to the Motor Vehicle Emissions Budget as a safely margin (see Section 4). 

 

Table 3-18. Emissions Decrease 

Pollutant Surplus 

Emissions* 

2007 to 2023 (tons) 

 

SO2 44,883

NOx ** 5,139

PM2.5 ** -152

* Surplus = (2007 emissions level) – (2023 emissions level) 

** These quantities do not reflect allotment to Motor Vehicle Emissions Budget 
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3.1.5 Verification of Continued Attainment 

Items 5.c and 5.d of the September 4, 1992, EPA guidance memo outline requirements for 

verification of continued attainment. Verification of continued attainment is accomplished through 

operation of the ambient PM2.5 monitoring network and through periodic updates of the area's 

emissions inventory. 

The location and operation of EPD’s FRM monitor in Floyd County are described in Section 2.1 of 

this plan. During the maintenance period, EPD will continue to operate a federal reference monitor 

in Floyd County per the requirements of 40 CFR Part 58. The Consolidated Emissions Reporting 

Rule (CERR) was promulgated by EPA on June 10, 2002. The CERR was replaced by the Annual 

Emissions Reporting Requirements (AERR) rule on December 17, 2008. The most recent triennial 

inventory for Georgia was compiled for 2008. The larger point sources of air pollution will continue 

to submit data on their emissions on an annual basis as required by the AERR. Emissions from the 

rest of the point sources, the nonpoint source portion and the onroad and nonroad mobile sources 

continue to be quantified on a 3-year cycle. The inventory will be updated and maintained on a 3-

year cycle. As required by the AERR, the next overall emissions inventory will be compiled for 

2011. 

3.2 Contingency Provisions 

Section 175A(d) of the Clean Air Act requires that the maintenance plan include provisions for 

contingency measures that would promptly be implemented to correct a violation of the standard, 

should this occur, after redesignation of an area as an attainment area. The measures may include 

rules or other measures that are not yet effective, but EPD agrees to adopt and implement, as 

expeditiously as practicable, when required by this plan. The minimum requirement for contingency 

provisions is the implementation of all measures that were contained in the SIP for the area (i.e., the 

nonattainment plan) before the redesignation. In addition, EPA guidance (John Calcagni memo 

dated September 4, 1992) specifies the following pertaining to contingency provisions in the 

maintenance plan: 

• identification of additional measures that would be considered for implementation should a 

violation occur; 

• identification of triggers for the implementation of additional contingency measures; and 

• a schedule and procedure for adoption and implementation of additional measures (with time 

limit). 

3.2.1 Contingency Measure Triggers 

Section 175A(d) of the Clean Air Act Amendments requires that the maintenance plan include 

provisions for contingency measures that would promptly be implemented by the state to correct any 

violation of the annual PM2.5 NAAQS after redesignation of an area as an attainment area. A list of 

potential contingency measures that could be considered for future implementation in such an event 

should also be included in the maintenance plan. 

EPD has developed a contingency plan for the Floyd County PM2.5 maintenance area. Contingency 

measures are intended to provide further emission reductions in the event that violations of the 

NAAQS occur after redesignation to attainment. Consistent with this plan, EPD agrees to adopt and 

implement, as expeditiously as practicable, the necessary corrective actions in the event that 
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violations of the standard occur within the maintenance area after redesignation to attainment. 

Contingency measures as described below would be adopted and implemented within 24 months of a 

contingency trigger unless EPD has demonstrated that technical or economic feasibility warranted a 

period longer than 24 months. 

EPD will use actual ambient monitoring and emissions inventory data as the indicators to determine 

whether contingency measures would be implemented. In accordance with 40 CFR Part 58, ambient 

monitoring data that indicates a violation of the annual PM2.5 NAAQS will begin the process to 

implement these contingency measures according to the protocols identified below. The contingency 

plan provides for corrective responses should the NAAQS be violated, or if emissions in the Floyd 

County maintenance area increase significantly above current levels. 

 

Tier I. A Tier 1 trigger is activated when any one of the following conditions occurs: 

• the previous calendar year’s annual average PM2.5 concentration exceeds the standard by 1.5 

ug/m3

 or more; 

• the annual average PM2.5 concentration in each of the previous two consecutive calendar 

years exceeds the standard by 0.5 ug/m3 or more; 

• the total maintenance area SO2 emissions in the most recent NEI exceeds the corresponding 

attainment-year inventory by more than 10.0 percent; and 

• the total maintenance area PM2.5 emissions in the most recent NEI exceeds the 

corresponding attainment-year inventory by more than 30.0 percent. 

EPD will conduct an evaluation as expeditiously as practicable to determine if the trend is likely to 

continue. If it is determined that additional emission reductions are necessary, EPD will adopt and 

implement any required measures in accordance with Section 3.2.2. 

The PM2.5 trigger concentrations described above apply to the PM2.5 federal reference monitor in the 

maintenance area. EPD will evaluate a Tier I condition, if it occurs, as expeditiously as practicable

to determine the cause(s) of the ambient PM2.5 or emissions inventory increase and to determine if a 

Tier II condition (see below) is likely to occur. 

Tier II. A Tier II trigger is activated when any violation of the annual PM2.5 NAAQS at any FRM 

ambient monitoring station in the Floyd County maintenance area is recorded, based on qualityassured monitoring data. In this event, EPD will conduct a comprehensive study to determine the 

cause(s) of the ambient PM2.5 increase and to determine if the increase is likely to continue and will 

implement any required measures as expeditiously as practicable, taking into consideration the ease 

of implementation and the technical and economic feasibility of selected measures. 

3.2.2 Schedule and Procedure for Adoption and Implementation of Contingency Measures 

EPD will, in the event of 1) a Tier II trigger condition or 2) a Tier I condition in which EPD has 

determined that a Tier II condition is likely to occur, conduct a comprehensive study to determine 

whether or not contingency measures are required for the maintenance of the PM2.5 standard. Since 

Floyd County may be influenced by emissions from outside the maintenance area, the study will 

attempt to determine whether the trigger condition is due to local emissions, emissions from 

elsewhere, or a combination of the previous. The comprehensive analysis, based on quality-assured 

ambient data, will examine: 
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• the severity of the trigger condition; 

• the meteorological conditions (in the case of an ambient concentration trigger) 

associated with the trigger condition; 

• potential contributing local emissions sources; 

• potential contributing emissions resulting from regional or long-range transport; 

• the geographic applicability of possible contingency measures; 

• emission trends, including implementation timelines of potential control measures; 

• timelines of “on-the-books” (adopted) measures that are not yet fully implemented [e.g., 

Georgia Rule (sss) and Rule (uuu) SO2 controls]; and 

• current and recently-identified control technologies. 

The comprehensive study will be completed and submitted to EPA as expeditiously as practicable but 

no later than nine months after the Tier I or Tier II trigger is activated. If EPD determines, through 

the comprehensive study, that contingency measures are required for maintenance of the standard, 

the appropriate corrective measures will be adopted and implemented within 18 to 24 months after 

the Tier I or II trigger occurs. These control measures, which will continue to produce substantial 

reductions in fine particulate matter and its precursors in excess of what is relied upon in this 

maintenance plan, include the Georgia Multipollutant Rule, which is described in Section 2.3.2.1 of 

this maintenance plan, as well as diesel engine retrofit, replacement, and repowering programs and 

truck stop electrification programs which are currently being implemented by Georgia EPD. 

If the study determines that additional measures are required, rules will be adopted no later than 18 

months following the date on which the Tier I or Tier II trigger is activated. Selection of measures 

will take into consideration the ease of implementation as well as technical and economic feasibility.

If it is determined that adoption and implementation of a rule will take longer than 24 months 

following the trigger date, EPD will submit for EPA’s approval a revised schedule for the 

development and adoption of contingency measures.

3.2.3 Contingency Measures 

If the analysis required above determines emissions from the local area are contributing to the trigger 

condition, EPD will evaluate those measures as specified in Section 172 of the CAA for control 

options as well as other available measures. If a new measure/control is already promulgated and 

scheduled to be implemented at the federal or state level, and that measure/control is determined to 

be adequate, additional local controls may be unnecessary. Under Section 175A(d), the minimum 

requirement for contingency measures is the implementation of all measures that were contained in 

the SIP before the redesignation. Currently all such measures are in effect for the Atlanta NAA; 

however, an evaluation of those measures, such as RACT, can be performed to determine those 

measures are adequate or up-to-date. In addition to those identified in Section 3.2.2, contingency 

measure(s) will be selected from the following types of measures or from any other measure deemed 

appropriate and effective at the time the selection is made: 

• Reasonably Available Control Measures (RACM) for sources of SO2 and PM2.5; 

• Reasonably Available Control Technology (RACT) for point sources of SO2 and PM2.5 ; 

• Expansion of RACM/RACT to area(s) of transport within the State; 

• Mobile source measures; and 

• Additional SO2 and/or PM2.5 reduction measures yet to be identified. 
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Any resulting contingency measure(s) will be based upon cost effectiveness, emission reduction 

potential, economic and social considerations, ease and timing of implementation, and other 

appropriate factors. 

Adoption of additional control measures is subject to necessary administrative and legal processes. 

EPD will solicit input from interested and affected persons (stakeholders) in the area prior to 

selecting appropriate contingency measures. No contingency measure will be implemented without 

providing the opportunity for full public participation. This process will include issuance of notices, 

an opportunity for public hearing, and other measures required by Georgia law. 
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4.0 Motor Vehicle Emissions Budget 

The transportation conformity rule (40CFR93.100 - 40CFR93.129) ensures that projects and plans 

funded by the Federal Highway Administration and the Federal Transit Administration conform to air 

quality SIPs and maintenance plans. In the case of a NAAQS maintenance plan, the rule requires a 

motor vehicle emissions budget (MVEB) to be established for the last year of the plan’s maintenance 

period. The rule, at 40CFR93.124(a), describes a motor vehicle emissions budget as "...the 

implementation plan's estimate of future [motor vehicle] emissions." Such budgets establish caps on 

motor vehicle emissions; projected emissions from transportation plans and programs must be equal 

to or less than these caps for a positive conformity determination to be made. Transportation 

conformity determinations are required for non-exempt federally-funded highway and transit 

projects before they are funded and approved and for transportation plans and transportation 

improvement programs. 

4.1 Pollutants 

For Floyd County, MVEBs will be set for direct PM2.5 and NOx only. 40 CFR Parts 93.119(f)(7) 

through (10) identify the PM2.5 pollutants which must be analyzed for transportation conformity 

purposes. These parts of the rule are listed below: 

§119(f)(7) - PM2.5 in PM2.5 areas; 

§119(f)(8) - Reentrained road dust in PM2.5 areas only if the EPA [Environmental Protection Agency] 

Regional Administrator or the director of the State air agency has made a finding that emissions 

from reentrained road dust within the area are a significant contributor to the PM2.5 nonattainment 

problem and has so notified the MPO and DOT [Department of Transportation]; 

§119(f)(9) - NOx

 [nitrogen oxides] in PM2.5 areas, unless the EPA Regional Administrator and the 

director of the State air agency have made a finding that emissions of NOx from within the area are 

not a significant contributor to the PM2.5 nonattainment problem and has so notified the MPO and 

DOT; and 

§119(f)(10) - VOC, SO2 and/or ammonia in PM2.5 areas if the EPA Regional Administrator or the 

director of the State air agency has made a finding that any of such precursor emissions from within 

the area are a significant contributor to the PM2.5 nonattainment problem and has so notified the 

MPO and DOT. 

Primary, or direct, PM2.5 emissions must be considered for all transportation conformity regional 

emissions analyses. For Floyd County, NOx must also be considered since EPA has not approved

Georgia EPD’s finding that NOx is not a significant contributor to the PM2.5 nonattainment problem 

in Floyd County. None of the other pollutants identified (re-entrained road dust, VOC, and 

ammonia) above have been determined by EPA or Georgia EPD to be significant contributors to PM 

nonattainment in Floyd County. SO2 from coal combustion is significant but levels of SO2 emissions 

from mobile sources are very low and, therefore, not significant for transportation conformity 

purposes. 
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4.2 Methodology 

In preparation of this Floyd County PM2.5 Maintenance Plan, EPD worked closely with the Georgia 

Department of Transportation (GDOT) and the Floyd-Rome Urban Transportation Study (FRUTS) to 

develop the estimates of mobile source emissions for the Floyd County nonattainment area. FRUTS 

is the metropolitan planning organization (MPO) for Rome/Floyd County. Mobile source inventories 

for 2023 were developed using the latest available planning assumptions, the most recent travel 

demand model, EPA's latest motor vehicle emission factor model, and vehicle population and age 

distributions developed from registration data obtained from R.L. Polk & Company. The 

methodology used to calculate the highway mobile source emissions on which the 2023 MVEBs are 

based is discussed below. 

Emissions from motor vehicles were estimated as a sum of products of vehicle activity measures and 

vehicle emissions factors. Vehicle activity measures (e.g. vehicle miles traveled, or VMT) are 

determined from a county-specific travel demand model. Vehicle emissions factors are determined 

from a motor vehicle emissions model. See Appendices C, C-3, and C-4 for more details on the 

development of the travel demand model and the determination of emissions factors. 

The MOVES2010a motor vehicle emission model was used to calculate 2023 emission factors with 

all currently known 2023 mobile source control rules in place. The MOVES model was run in 

Inventory Mode. The emission factors reflect all federal controls, e.g., the Federal Motor Vehicle 

Control Program, including Tier 1 and (beginning with 2006 models) Tier 2 tailpipe standards, and 

the National Low Emission Vehicle program. MOVES2010a produces three sets of emission factors 

per run: 

• rate per distance; 

• rate per vehicle; and 

• rate per profile. 

Of these three types of emission factors, the first is multiplied by VMT and the second two by 

vehicle population. Note that rate-per-profile emissions (i.e., vapor venting) are not applicable to 

PM2.5 modeling. 

The FRUTS travel demand model is developed and maintained by GDOT. Inputs to the model are 

socioeconomic data and the highway network that consists of roadway segments (links) and 

intersections (nodes). Outputs include vehicle activity, number of trips, vehicle population, and other 

data. The use of a county-specific travel demand model for transportation conformity calculations is 

consistent with the transportation conformity rule at 40CFR93.122(b) and (d), which requires a 

network-based travel model emissions estimation methodology if the use of such procedures has 

been the previous practice of the MPO. The use of such a methodology has been the previous 

practice of FRUTS. 

Section 93.105(b) of the Transportation Conformity Rule and Sections 106(g) and 106(h) of 

Georgia's transportation conformity SIP require interagency consultation for SIP development. 

Accordingly, a detailed listing of the procedures and planning assumptions used for the regional 

emissions analysis supporting development of the MVEB was presented to the Rome/Floyd 

interagency consultation committee for review on September 15, 2011. The assumptions used to 

develop Rome's conforming Long Range Transportation Plan and Transportation Improvement 

Program were also used to develop the network and emissions for this maintenance plan MVEB. 
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4.3 Motor Vehicle Emissions Budgets and Safety Margins 

The projected 2023 on-road motor vehicle emissions for direct PM2.5 and NOx are 31.8 and 847.0 

tons, respectively. A budget for SO2 is not required. On-road emissions of SO2 are considered to be 

“de-minimis” (70FR 24283), and, therefore, no budget is necessary. The on-road mobile emissions, 

emissions budgets, and safety margins are presented in Table 4-1. A safety margin is necessary to 

accommodate the variabilities or worst-case scenarios that can occur due to future planning 

assumptions. 

The worst-case daily motor vehicle emissions projection for PM2.5 is 19.5 percent above the 

projected 2023 on-road emissions. In a worst-case scenario, the needed annual safety margin for the 

MVEB would be 6.2 tons resulting in an overall MVEB of 38.0 tons per year. 

The worst-case daily motor vehicle emissions projection for NOx is 17.4 percent above the projected 

2023 on-road emissions. In a worst-case scenario, the needed annual safety margin for the MVEB 

would be 147.4 tons resulting in an overall MVEB of 994.4 tons per year. 

Table 4-1. 2023 Motor Vehicle Emissions, Emissions Budgets, and Safety Margins 

Pollutant Projected 2023 

On-Road 

Emissions 

(tons) 

Safety Margin 

Allotted to MVEB 

(%) 

Safety Margin 

Allotted to 

MVEB (tons) 

MVEB with Safety 

Margin (tons) 

PM2.5 31.8 19.5 6.2 38.0

NOx 847.0 17.4 147.4 994.4
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5.0 Conclusion 

Section 107(d) of the CAA states that an area can be redesignated to attainment if the following 

conditions are met: 

1. The EPA has determined that the NAAQS has been attained. 

2. The applicable implementation plan has been fully approved by EPA under Section 110(k). 

3. The EPA has determined that the improvement in air quality is due to permanent and 

enforceable reductions in emissions. 

4. The state has met all applicable requirements for the area under Section 110 and Part D. 

5. The EPA has fully approved a maintenance plan, including a contingency plan, for the area 

as required by CAA Section 175A. 

Table 5-1. Summary of Projected SO2 Emissions – Total of All Sectors (tons) 

Source 

2007 

attainment 

(tons) 

2014 

(tons) 

2017 

(tons) 

2020 

(tons) 

2023 

(tons) 

Point - total 51,275 19,666 6,119 6,242 6,366

Area - total 758 784 794 807 819

Non-road - 

total 

29 9 1 1 1

Onroad 14 12 11 9 8

Total 52,077 20,471 6,925 7,060 7,194
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Table 5-2. Summary of Projected NOx Emissions – Total of All Sectors (tons) 

Source 

2007 

attainment 

(tons) 

2014 

(tons) 

2017 

(tons) 

2020 

(tons) 

2023 

(tons) 

Point - total 10,165 8,267 7,453 7,660 7,866

Nonpoint - total 936 1,026 1,066 1,104 1,144

Non-road - total 996 728 613 546 479

Onroad 3,378 2271 1796 1322 847

Onroad Safety 

Margin 

147.4

Total 15,475 12,292 10,928 10,632 10,483

 

Table 5-3. Summary of Projected PM2.5 Emissions – Total of All Sectors (tons) 

Source 

2007 

attainment

(tons) 

2014 

(tons) 

2017 

(tons) 

2020 

(tons) 

2023

(tons) 

Point - total 953 774 697 722 747

Nonpoint - total 1,855 2,072 2,164 2,249 2,333

Non-road - total 66 48 40 36 31

Onroad 117 80 64 48 32

Onroad Safety 

Margin 

6.2

Total 2,991 2,973 2,965 3,054 3,149 

 
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The supporting documentation to show that the above conditions have been met for Floyd 

County is contained in this document. Based on the 2007-2009 monitored design value for the Floyd 

County nonattainment area, EPA has published in the Federal Register its final rule that the 

nonattainment area has attained the 1997 annual average PM2.5 National Ambient Air Quality 

Standard (NAAQS). The maintenance demonstration in this document shows that, based on 

comparison of projected emissions to attainment year emissions, emissions are expected to stay at or 

below levels commensurate with attaining air quality through the year 2023 as illustrated by Tables 

5-1, 5-2 and 5-3 above. Analysis was presented to demonstrate that the standard will be maintained 

despite a small, projected increase in direct PM2.5 emissions. This document also contains provisions

for contingency measures should emissions levels or ambient concentrations rise unexpectedly. 

EPA’s concurrence that the improvement in Floyd County’s air quality is due to permanent and 

enforceable reductions in emissions, and EPA’s approval of this document will satisfy Items 3 and 5 

above. Therefore, Georgia EPD requests that the Floyd area be redesignated from nonattainment to 

attainment with respect to the 1997 annual NAAQS for fine particulate matter. In addition, 2023 

MVEBs have been presented for onroad mobile emissions of direct PM2.5 and NOx. These emissions 

budgets are required by EPA’s transportation conformity rule as tools for ensuring conformance of 

highway and transit plans with air quality SIPs and maintenance plans. 
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6.0 References 

State of Georgia, Rules for Air Quality Control, Chapter 391-3-1, Effective September 13, 2011. 

US Energy Information Administration, Annual Energy Outlook 2010, April 2010. 

USEPA, Air Quality Modeling Final [Cross-state Air Pollution] Rule Technical Support Document, 

June 2011, Docket ID No. EPA-HQ-OAR-2009-0491-4140.

USEPA, “Approval, and Promulgation of Air Quality Implementation Plans; Indiana; Redesignation 

of the Evansville Area to Attainment of the Fine Particulate Matter Standard’; proposed rule, 76 FR 

29695. 

USEPA, “Clean Data Policy for the Fine Particle National Ambient Air Quality Standards,” 

Memorandum from Stephen Page, December 14, 2004. 

USEPA, “Determination of Attaining Data for the 1997 Annual Fine Particulate Standard; Rome, 

Georgia, Final Rule”; 76 FR 18650 – 18651. 

USEPA, “Federal Implementation Plans: Interstate Transport of Fine Particulate Matter and Ozone 

and Correction of SIP Approvals” [a.k.a. “Cross-State Air Pollution Rule”]; final rule, 76 FR 48208. 

USEPA, National Emissions Inventory: inventory years 2005, 2007, and 2008. 

USEPA, “Procedures for Processing Requests to Redesignate Areas to Attainment,” Memorandum 

from John Calcagni, September 4, 1992.