i 

Georgia's Redesignation Request and 

Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour 

Ozone NAAQS 

March 21, 2012 

Prepared by:

Georgia Department of Natural Resources 

Environmental Protection Division 

Air Protection Branch 
 Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

i 

Executive Summary 

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

the metro Atlanta region 8-hour ozone nonattainment area be redesignated to attainment with respect 

to the 1997 National Ambient Air Quality Standard (NAAQS) for Ozone. This document also 

includes Georgia’s plan to maintain attainment of the ozone standard in the Atlanta area for the 

counties of Barrow, Bartow, Carroll, Cherokee, Clayton, Cobb, Coweta, DeKalb, Douglas, Fayette, 

Forsyth, Fulton, Gwinnett, Hall, Henry, Newton, Paulding, Rockdale, Spalding, and Walton. 

This request is based on three years, 2008-2010, of ambient monitoring data showing attainment of 

the standard (0.084 ppm) consistent with the policy memo addressing clean data for ozone (John S. 

Seitz 05/10/1995); the implementation of permanent and enforceable reductions in ozone precursor 

emissions; compliance with all applicable requirements, and the Atlanta Area Maintenance Plan with 

emission projections demonstrating that the 2008 emissions levels (emissions levels during clean 

data period) will not be exceeded through the year 2024. 
 Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

ii 

TABLE OF CONTENTS 

Executive Summary ......................................................................................................................... i

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

1.1 Atlanta Area Nonattainment Designations ....................................................................... 1

1.2 Redesignation Request ........................................................................................................ 3

1.3 Maintenance Plan ................................................................................................................ 4

2.0 Redesignation Request ................................................................................................. 5

2.1 Attainment of the Ozone 8-Hour NAAQS ........................................................................ 5

2.1.1 Monitoring Network ................................................................................................................... 5

2.1.2 Ambient Ozone Data .................................................................................................................. 7

2.1.3 Clean Data Determination and Determination of Attainment by Applicable Attainment Date .. 8

2.2 Implementation Plan Under Section 110(k) ...................................................................... 8

2.3 Permanent and Enforceable Reductions in Emissions..................................................... 9

2.3.1 State Control Measures - Georgia ............................................................................................... 9

2.3.1.1 Smoke Management Plan ..................................................................................................... 11

2.3.1.2 Georgia Rule (yy) ................................................................................................................. 12

2.3.1.3 Georgia Rule (lll) .................................................................................................................. 13

2.3.1.4 Georgia Rule (jjj) .................................................................................................................. 13

2.3.1.5 Georgia Rule (rrr) ................................................................................................................. 13

2.3.1.6 Georgia Rule (sss) Multipollutant Rule: NOx and SO2 Controls ......................................... 13

2.3.2 Federal Control Measures ......................................................................................................... 15

2.3.2.1 Clean Air Interstate Rule and Cross-State Air Pollution Rule .............................................. 17

2.3.2.2 Tier 2 Vehicle Standards ...................................................................................................... 17

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

Rule 18

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

2.3.2.5 Nonroad Large Spark-Ignition Engines and Recreational Engines Standard ....................... 18

2.3.2.6 NOx SIP Call in Surrounding States .................................................................................... 18

2.4 Section 110 and Part D Requirements ............................................................................. 19

3.0 Maintenance Plan ...................................................................................................... 20

3.1 Maintenance Demonstration ............................................................................................ 20

3.1.1 Attainment Year Emissions Inventory ...................................................................................... 20

3.1.1.1 Point Sources ........................................................................................................................ 22

3.1.1.2 Nonpoint Sources ................................................................................................................. 23

3.1.1.3 Onroad Mobile Sources ........................................................................................................ 24

3.1.1.4 Nonroad Mobile Sources ...................................................................................................... 25

3.1.1.5 Summary of 2008 Emissions Inventory ............................................................................... 25

3.1.2 Emissions Projections ............................................................................................................... 26

3.1.2.1 Methods and Projected Inventories ...................................................................................... 26

3.1.2.2 Emissions Decreases ............................................................................................................ 34

3.1.3 Verification of Continued Attainment ...................................................................................... 34
 Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

iii 

3.2 Contingency Provisions ..................................................................................................... 34

3.2.1 Contingency Measure Triggers ................................................................................................. 35

3.2.2 Schedule and Procedure for Adoption and Implementation of Contingency Measures ............ 36

3.2.3 Contingency Measures .............................................................................................................. 36

4.0 Motor Vehicle Emissions Budget ............................................................................... 38

4.1 Pollutants ........................................................................................................................... 38

4.2 Methodology ...................................................................................................................... 38

4.3 Motor Vehicle Emissions Budgets and Safety Margins.................................................. 39

5.0 Conclusion ................................................................................................................. 41

6.0 References .................................................................................................................. 43
 Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

iv 

LIST OF FIGURES 

Figure 1-1. 1997 Ozone NAAQS Nonattainment Area in Georgia ................................................ 2

Figure 2-1. Locations of ozone monitors within the Atlanta 20-county nonattainment area. ..... 6

Figure 2-2. Locations and 2007 energy production of coal-fired EGU facilities in the Atlanta 

NAA ............................................................................................................................................ 14
 Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

v 

LIST OF TABLES 

Table 2-1. Metro Atlanta Data Collection Sites ............................................................................... 7

Table 2-2. Design Values for Counties in the Atlanta, Georgia Nonattainment Area for the 1997 

8-Hour Ozone NAAQS ............................................................................................................... 8

Table 2-3. Timetable of State NOx Measure Implementation ...................................................... 10

Table 2-4. Timetable of Federal NOx Measure Implementation ................................................. 16

Table 3-1. 2007 Emissions Inventory Sources ................................................................................ 21

Table 3-2. Ozone Season Daily Emissions by EGU facilities in 2008, 2017 and 2024, tons/day . 22

Table 3-3. Point Source Emissions for 2008 (tons, summer day) ................................................. 23

Table 3-4. Nonpoint Source Emissions for 2008 (tons, summer day) .......................................... 24

Table 3-5. Nonroad Mobile Source Emissions for 2008 (tons, ozone season summer day) ....... 25

Table 3-6. Attainment-year (2008) Emissions Inventory (tons, summer day) ............................. 26

Table 3-7. Basis of Control and Growth Factors for 2017 and 2023 Inventories ....................... 27

Table 3-8. Growth factors by SCCs for EGU sources .................................................................... 28

Table 3-9. Projected Point Source Emissions (tons, summer day) ............................................... 30

Table 3-10. Projected Nonpoint Source Emissions (tons, summer day) ...................................... 31

Table 3-11. Projected Onroad Mobile Source Emissions (tons, summer day) ............................ 32

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

Table 3-13. Projected Emissions – Total of All Sectors (tons, summer day) ................................ 33

Table 3-14. Emissions Decreases ..................................................................................................... 34

Table 4-1. Motor vehicle projected emissions, safety margins and emissions budgets .............. 40

Table 5-1. Summary of Projected NOx Emissions – Total of All Sectors (tons, summer day) .. 41

Table 5-2. Summary of Projected VOC Emissions – Total of All Sectors (tons, summer day) .. 42
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

vi 

LIST OF APPENDICES 

Appendix A Georgia’s Smoke Management Plan and Memorandum of Understanding 

Appendix B EPD’s Methodology for Emissions Projections [including interpolation calculations]

Appendix B-1 EGU Control Schedules and Efficiencies – Atlanta NAA 

Appendix B-2 Summary of EGAS Derived SCC-Specific Growth Factors 

Appendix B-3 Summary Emissions Inventory for the Atlanta Ozone Nonattainment Area 

Appendix B-4 Analysis of Nonroad Emissions 

Appendix B-5 Nonroad Growth Factors and SEMAP Rail and CMV Factors 

Appendix B-6 Aircraft and Locomotive SCC-Specific Emissions, Growth and Control Factors 

Appendix B-7 MOVES Inputs, Documentation, and Outputs 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

vii 

List of Acronyms 

Acronym Meaning Acronym Meaning 

AEO Annual Energy Outlook MVEB Motor Vehicle Emissions Budget 

AERR Annual Emissions Reporting 

Requirements 

NEI National Emissions Inventory 

AQS Air Quality System NEMS National Energy Modeling System 

ARC Atlanta Regional Commission NMIM National Mobile Inventory Model 

CAA Clean Air Act NOx Nitrogen Oxides 

CAMD Clean Air Markets Division NTE Not-to-exceed 

CARB California Air Resources Board PMF Positive Matrix Factorization 

CERR Consolidated Emissions Reporting 

Rule 

RACM Reasonably Available Control Measures 

E-GAS Economic Growth Analysis System RACT Reasonably Available Control Technology 

EGU Electric Generating Unit RFP Reasonable Further Progress 

EIA Energy Information Administration SCC Source Classification Code 

EPD Environmental Protection Division SEMAP Southeastern Modeling And Planning 

ERTAC Eastern Regional Technical Advisory 

Committee 

SIP State Implementation Plan 

FRM Federal Reference Method SOA Secondary Organic Aerosols 

GDOT Georgia Dept. of Transportation STN Speciated Trends Network 

HPMS Highway Performance Monitoring 

System 

TDM Travel Demand Model 

ICI Industrial and 

Commercial/Institutional 

VISTAS Visibility Improvement State and Tribal 

Association of the Southeast 

MPO Metropolitan Planning Org. VMT Vehicle Miles Traveled 

MOVES Motor Vehicle Emissions Simulator VOC Volatile Organic Compounds 

MSA Metropolitan Statistical Area 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

1 

1.0 Introduction 

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

(EPD’s) request that the metro Atlanta nonattainment area be redesignated as an area attaining the 

1997 National Ambient Air Quality Standard (NAAQS) for ozone 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, in memorandums on September 4 and October 

28 of that year from John Calcagni.1

1.1 Atlanta Area Nonattainment Designations 

1990 1-Hour Ozone Standard 

Pursuant to the Clean Air Act Amendments of 1990 (CAAA), the Atlanta area was designated as 

nonattainment for the 1-hour ozone NAAQS by U.S. EPA and was classified as a serious 

nonattainment area on November 6, 1991. The nonattainment area (NAA) was, at that time, 

geographically defined as the following 13 Georgia counties: Cherokee, Clayton, Cobb, Coweta, 

DeKalb, Douglas, Fayette, Forsyth, Fulton, Gwinnett, Henry, Paulding, and Rockdale. Because 

Atlanta failed to attain the 1-hour ozone NAAQS by November 15, 1999, EPA issued a final 

rulemaking action in the September 26, 2003, Federal Register (68 FR 55469) determining that, by 

operation of law, the Atlanta area was being reclassified as a "severe" ozone nonattainment area 

effective January 1, 2004. In addition to having been required to submit state implementation plan 

(SIP) revisions meeting requirements for marginal, moderate, and serious ozone nonattainment areas, 

Georgia was required to submit plans meeting the additional requirements for areas classified as 

severe. As a result of EPA's implementation of the original federal Clean Air Act of 1970, the Clean 

Air Act Amendments of 1977, and the Clean Air Act Amendments of 1990, Georgia EPD 

completed, and EPA approved (67 FR 30574), SIP revisions to address the 1-hour ozone Atlanta 

NAA. 

On February 1, 2005, EPD requested under the CAAA of 1990 that the Atlanta area be redesignated 

from nonattainment to attainment with respect to the 1-hour ozone NAAQS. This request was based 

on three years, 2002 through 2004, of ambient monitoring data at all 11 ozone monitors in the 

Atlanta NAA showing no violation of the 1-hour ozone NAAQS; the implementation of permanent 

and enforceable reductions in ozone precursor emissions; compliance with all applicable 

requirements; and the Atlanta Maintenance Plan with projections demonstrating that the 2002 

emission levels in this area will not be exceeded through at least the year 2015. EPD also petitioned 

EPA to make a determination that the Atlanta area was eligible for application of EPA's Clean Data 

Policy, based on the Atlanta area's attainment of the 1-hour ozone NAAQS. EPA approved the plan 

and redesignation request effective June 14, 2005 (70 FR 34660). 

1997 8-Hour Ozone Standard 

Georgia EPD submitted its nonattainment area designation recommendations under the 8-hour ozone 

standard to EPA on July 15, 2003. Georgia recommended the following counties be designated 

 

1

 “Procedures for Processing Requests to Redesignate Areas to Attainment”, September 4, 1992, and “State 

Implementation Plan (SIP) Requirements Submitted in Response to Clean Air Act (Act) Deadlines”, October 

28, 1992. 

John Calcagni, Director, Air Quality Management Division, OAQPS, USEPA. 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

2 

nonattainment for the 8-hour ozone standard: Barrow, Bartow, Carroll, Cherokee, Clayton, Cobb, 

Coweta, DeKalb, Douglas, Fayette, Forsyth, Fulton, Gwinnett, Hall, Henry, Newton, Paulding, 

Rockdale, Spalding, and Walton. Georgia recommended that Pickens County be excluded from the 

nonattainment designation even though the county is part of the Atlanta MSA. Georgia based this 

exclusion, in part, on the fact that the county did not exceed any of the State's criteria for inclusion 

into a nonattainment area. Other parameters used in the analysis included the county's population and 

summer day NOx and VOC emissions. EPA concurred with Georgia's recommendations in a letter 

dated December 3, 2003. 

Figure 1-1. 1997 Ozone NAAQS Nonattainment Area in Georgia 

On April 30, 2004, EPA designated 20 metropolitan Atlanta counties as a "marginal" nonattainment 

area under the 1997 8-hour ozone standard. The eight-hour ozone nonattainment area encompasses 

the 13 counties of the former 1-hour ozone nonattainment area plus seven additional "ring" counties: 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

3 

Barrow, Bartow, Carroll, Hall, Newton, Spalding, and Walton. With an attainment deadline of June 

15, 2007, marginal areas were required to attain the National Ambient Air Quality Standard 

(NAAQS) by the 2006 ozone season. On October 16, 2007, the U.S. EPA published a rulemaking 

proposing its determination that the Atlanta Area did not attain the 8-hour ozone NAAQS by June 15, 

2007, the applicable attainment date for marginal nonattainment areas. The proposed finding was 

based on ambient air quality data from years 2004, 2005, and 2006. The U.S. EPA explained that, 

consistent with Section 181(b)(2) of the Clean Air Act (CAA), when EPA finalizes its determination 

that the Atlanta Area failed to attain, and that requirement becomes effective, the Atlanta Area would 

be reclassified by operation of law to the next highest classification or “moderate” nonattainment. 

The "moderate" area attainment date for the Atlanta, Georgia, area would then be "as expeditiously 

as practicable," but no later than June 15, 2010. The U.S. EPA finalized this finding on March 6, 

2008 [73FR 12013-12017]. 

The State of Georgia prepared and submitted an ozone attainment demonstration plan for the metro 

Atlanta 8-hour Ozone Nonattainment Area to EPA Region 4 on October 21, 2009. The plan was 

based on a modeled attainment demonstration performed according to EPA guidance. The modeling 

resulted in a single monitor in the Atlanta NAA exceeding the 8-hour ozone NAAQS (design value 

of 86 ppb at the Confederate Avenue monitoring site). However, the weight of evidence analysis 

demonstrated in Section 6.2 of the October 2009 plan provides strong evidence that the Atlanta 8-

Hour Ozone NAA would demonstrate attainment of the ozone NAAQS by 2009. The attainment 

demonstration with the weight of evidence analysis was shown to be effective since the unmonitored 

area analysis showed no modeling grid cell greater than 86 ppb. 

On June 9, 2010, Georgia EPD submitted a request for a one-year extension of the attainment date in 

accordance with 40 CFR 51.907. The Atlanta nonattainment area qualified for an extension because 

it had met the condition specified in 69 FR 23968 in which an area is eligible for the first of the 1-

year extensions if, for the attainment year, the area’s fourth highest daily 8-hour average is 0.084 

ppm or less. On November 30, 2010, EPA published a final rule extending the attainment date for 

the Atlanta nonattainment area to June 15, 2011 [75FR 73969-73972]. 

EPA has since determined that the area has met attainment (see Section 2). Thus, the SIP 

requirements that the October 21, 2009 attainment demonstration submission were required to fulfill 

are no longer applicable. 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) and contingency requirements upon 

clean data determination is specified and authorized in a May 10, 1995 memo from John S. Seitz of 

U.S. EPA. 

1.2 Redesignation Request 

This document contains Georgia's request that the metro Atlanta nonattainment area be redesignated 

to attainment with respect to the 1997 8-hour NAAQS for ozone. 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. 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

4 

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

as required by CAA Section 175A. 

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 5th 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 guidance,2

 the metro Atlanta 8-hour ozone 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. 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

5 

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 8-hour ozone NAAQS based on ambient data from 2008 through 2010 

 Approval by EPA of the implementation plan under Section 110(k). 

 Improvement of air quality with respect to ozone that is due to permanent and 

enforceable reductions in emissions. 

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

2.1 Attainment of the Ozone 8-Hour NAAQS 

A monitoring site is in attainment of the 8-hour ozone standard when the average of the annual 

fourth-highest daily maximum concentration over three consecutive years measured at the monitor 

does not exceed 0.084 ppm. This 3-year average is termed the design value for the monitor. The data 

must be complete and quality-assured, consistent with 40 CFR Part 58 requirements and other 

relevant EPA guidance. Therefore, for a single site to meet the standard, the 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 design values for metro Atlanta monitors, based on data from 2008 through 2010, ranges from 

0.068 ppm to 0.080 ppm, which demonstrates attainment of the standard. The monitoring network 

and ambient ozone data are presented below. 

2.1.1 Monitoring Network 

Ozone is monitored using EPA-approved reference or equivalent methods. These analyzers 

continuously measure the concentration of ozone in the ambient air using the ultraviolet photometric 

method. According to 40 CFR Part 58, the State of Georgia operates ozone monitors each year from 

March 1st through October 31st, with the exception of the NCore (National Core Monitoring 

Network) ozone monitor that operates year-round. During the monitoring season, analyzers are 

subjected to multiple calibration checks, and on an annual basis, EPD’s Quality Assurance Unit 

audits these samplers. 

Georgia EPD began monitoring ozone at the South DeKalb site (13-089-0002), which is within the 

Atlanta-Sandy Springs-Marietta MSA, in 1974. Since that time, the ozone monitoring network has 

grown to more than ten ozone monitors operating within the Atlanta-Sandy Springs-Marietta MSA, 

currently as part of the State and Local Ambient Monitoring Stations (SLAMS). With the 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

6 

development of the Photochemical Assessment Monitoring Stations (PAMS) network, the Yorkville 

(13-223-0003), South DeKalb (13-089-0002), and Conyers (13-247-0001) ozone monitors were 

designated PAMS sites, as well. Two sites are currently not operating, the Tucker-Idlewood Road 

monitor (13-089-3001), which is permanently shutdown, and the Fayetteville-Georgia DOT (13-113-

0001) monitor, which is temporarily shutdown. Table 2-1 lists the metro Atlanta ozone monitors 

shown in Figure 2-1 and their respective start dates. 

Figure 2-1. Locations of ozone monitors within the Atlanta 20-county nonattainment 

area.
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

7 

Table 2-1. Metro Atlanta Data Collection Sites 

Site Name AQS* 

Site ID Start Date End Date 

Kennesaw-GA National Guard McCollum Parkway 13-067-0003 Sept. 1, 1999 

Newnan-University of W. Georgia at Newnan 13-077-0002 May 5, 1999 

South DeKalb-2390-B Wildcat Road 13-089-0002 Jan. 1, 1974 

Douglasville- W. Strickland St. 13-097-0004 Aug. 15, 1997 

Gwinnett Tech- 1250 Atkinson Rd. 13-135-0002 March 17, 1995 

McDonough-Henry County Extension Office 13-151-0002 June 7, 1999 

Yorkville-King Farm 13-223-0003 Jan. 1, 1996 

Conyers-Monastery 3780 GA Highway 212 13-247-0001 June 26, 1978 

Confederate Ave. 13-121-0055 Oct. 1, 1991 

Tucker-Idlewood Road 13-089-3001 July 19, 1990 Oct. 31, 2006 

Fayetteville-GA DOT 13-113-0001 April 1, 1998 Oct. 31, 2008** 

*EPA’s Air Quality System. 

**Temporarily discontinued. 

2.1.2 Ambient Ozone Data 

Table 2.2 shows the 8-hour ozone concentrations and the associated 3-year design value average that 

demonstrate attainment of the standard in the metro Atlanta area. The 2008–2010 3-year design 

values range from 0.068 ppm to 0.080 ppm, all of which are below the standard of 0.084 ppm. 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

8 

Table 2-2. Design Values for Counties in the Atlanta, Georgia Nonattainment Area for 

the 1997 8-Hour Ozone NAAQS

*Temporarily discontinued as detailed in EPD’s Ambient Air Monitoring Plan approved by EPA. 

2.1.3 Clean Data Determination and Determination of Attainment by Applicable Attainment Date 

On June 23, 2011, EPA promulgated its determination [76 FR 36873] that the metro Atlanta 

nonattainment area had attained the 1997 8-Hour Ozone National Ambient Air Quality Standard 

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

data for the 2008-2010 period, which showed design values ranging from 0.068 ppm to 0.080 ppm. 

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

submit an attainment demonstration, a reasonable further progress (RFP) plan, and contingency 

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

This final rule became effective on July 25, 2011. On December 15, 2011, EPA proposed its 

determination [76 FR 77950] that the metro Atlanta nonattainment area has attained the 1997 8-hour 

ozone NAAQS by its applicable attainment date of June 15, 2011. 

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 an ozone attainment demonstration plan for the 

metro Atlanta nonattainment area. The plan was submitted for approval to EPA Region 4 on October 

21, 2009. As discussed in Section 1.1 of this plan, the attainment demonstration, RFP, and 

contingency requirements that the October 21, 2009 SIP revision were required to fulfill are no 

Design Values for Counties in the Atlanta, Georgia Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

Location AQS site ID 2008 

(ppm) 

 

2009 

(ppm) 

2010 

(ppm) 

2008-

2010 

Design 

value 

(ppm) 

Cobb County GA National Guard McCollum Parkway (13-067-0003) 0.075 0.076 0.079 0.076 

Coweta County University of W. Georgia at Newnan (13-077-0002) 0.075 0.065 0.065 0.068 

Dekalb County 2390-B Wildcat Road Decatur, GA (13-089-0002) 0.087 0.077 0.075 0.079 

Douglas County Douglasville W. Strickland St. (13-097-0004) 0.080 0.072 0.074 0.075 

Gwinnett County Gwinnett Tech 1250 Atkinson Rd. (13-135-0002) 0.079 0.073 0.072 0.074 

Henry County Henry County Extension Office (13-151-0002) 0.086 0.074 0.078 0.079 

Paulding County Yorkville (13-223-0003) 0.072 0.067 0.071 0.070 

Rockdale County Conyers Monastery 3780 GA Hwy. 212 (13-247-0001) 0.089 0.070 0.076 0.078 

Fulton County Confederate Ave. (13-121-0055) 0.084 0.077 0.080 0.080 

Fayette County Fayetteville – GDOT (13-113-0001) 0.086 ----* ----* ----* 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

9 

longer applicable. Therefore, the attainment demonstration has been withdrawn and substituted with 

submittal of this maintenance plan. 

2.3 Permanent and Enforceable 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 ozone concentrations during the years 2008 

through 2010 is due to permanent and enforceable reductions 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: 

 State control measures and associated emissions reductions. 

 Federal control measures and associated emissions reductions. 

2.3.1 State Control Measures - Georgia 

Since the metro Atlanta region was designated nonattainment for both the federal ozone and PM2.5 

standards, control strategies for the ozone NAAQS and PM2.5 and have been integrated and 

harmonized to the maximum extent possible. Control of NOx and VOC is generally considered the 

most important component of an ozone control strategy, and NOx and VOC make up the largest 

controllable contribution to ambient ozone. However, the metro Atlanta nonattainment area has 

shown a greater sensitivity of elevated ozone to NOx controls rather than VOC controls due to the 

biogenic nature of VOC emissions in Georgia. Therefore, implemented control measures have 

focused on the control of NOx emissions. State enforced measures that target reduction of these 

emissions are listed below. 

NOx emission limitation and standard provisions in Georgia Rule 391-3-1-.02(2) are established for 

various external and internal combustion devices and consist of emission standards and work 

practice requirements. State measures that target the reduction of NOx emissions that have resulted 

in reductions since the 2002 baseline inventory are: 

 Smoke Management Plan 

 Georgia Rule (yy) – Emissions of Nitrogen Oxides 

 Georgia Rule (lll) - NOx from Fuel Burning Equipment 

 Georgia Rule (rrr) - NOx from Small Fuel Burning Equipment 

 Georgia Rule (jjj) - NOx from EGUs 

 Georgia Rule (sss) - Multipollutant Rule 

Table 2-3 shows the timetable of implementation of these measures as well as the species controlled 

by each. This table also includes the measured fourth highest ozone levels at each of the monitors in 

the nonattainment area during this time period. The correlation between the drop in ozone 

concentrations and the implementation of the control measures, particularly Georgia Rule 391-3-1-

.02(2)(sss), lend strong evidence that the improvements in air quality are a result of reductions in 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

10 

emissions and not a meteorological influenced phenomenon. Detailed discussions of the measures 

are presented in the following subsections. 

Table 2-3. Timetable of State NOx Measure Implementation 

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 

Ozone 4th Max 

Monitors 

GA National 

Guard 

McCollum 

Parkway 0.088 0.100 0.084 0.073 0.081 0.093 0.089 0.079 0.076 0.079 

University of 

W. Georgia at 

Newnan 0.085 0.099 0.077 0.083 0.078 0.086 0.091 0.075 0.065 0.065 

2390-B 

Wildcat Road 

Decatur, GA 0.085 0.095 0.083 0.084 0.087 0.096 0.096 0.087 0.077 0.075 

Douglasville 

W. Strickland 

St. 0.092 0.098 0.085 0.080 0.089 0.095 0.086 0.080 0.072 0.074 

Gwinnett Tech 

1250 Atkinson 

Rd. 0.080 0.089 0.088 0.092 0.082 0.096 0.092 0.081 0.073 0.072 

Henry County 

Extension 

Office 0.086 0.099 0.082 0.085 0.089 0.095 0.102 0.086 0.074 0.078 

Yorkville 0.085 0.099 0.083 0.073 0.082 0.084 0.085 0.073 0.067 0.071 

Conyers 

Monastery 

3780 GA Hwy. 

212 0.091 0.099 0.078 0.087 0.088 0.099 0.095 0.090 0.070 0.076 

Confederate 

Ave. 0.084 0.100 0.091 0.089 0.092 0.092 0.086 0.086 0.077 0.080 

Fayetteville – 

GDOT 0.099 0.091 0.083 0.083 0.082 0.087 0.090 0.086 ---* ---* 

Measure Pollutants 

Controlled 

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 

Smoke Management 

Plan 

NOx, PM X X X 

Georgia Rule 391-3-1-

.02(2) (yy): Emissions 

of Nitrogen Oxides 

from Major Sources 

(expansion of 

applicable area) 

NOx X X X X X X X X 

Georgia Rule 391-3-1-

.02(2) (lll): NOx from 

Fuel Burning 

Equipment 

NOx X X X X X X X X X X 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

11 

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 

Georgia Rule 391-3-1-

.02(2) (jjj): NOx from 

EGUs 

NOx X X X X X X X X 

Georgia Rule 391-3-1-

.02(2) (rrr): NOx from 

Small Fuel Burning 

Equipment 

NOx X X X 

Georgia Rule 391-3-1-

.02(2)(sss): 

Multipollutant Rule 

NOx, SO2 X** X X 

* Temporarily discontinued as detailed in EPD’s Ambient Air Monitoring Plan approved by EPA 

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

2.3.1.1 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. 

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 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 

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 A. 

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. 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

12 

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. 

In addition to mitigating the impacts of prescribed burns on air quality, the implementation of a 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 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 in the state of Georgia 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 smoke-sensitive area. This measure is a state-only requirement and is therefore not 

federally enforceable. This measure is not necessary for the continued maintenance of the Atlanta 

NAA area, however the implementation of this plan will support the maintenance of the ozone 

NAAQS for the Atlanta area. 

2.3.1.2 Georgia Rule (yy) 

Georgia Rule (yy) is a case-by-case RACT determination for major sources of NOx emissions that 

applies to sources with a potential to emit NOx greater than 25 tons per year in the original 13-

nonattainment counties and to those sources in the additional 7-county nonattainment area that have 

a potential to emit greater than 100 tons of NOx per year. This rule has changed over the years based 

on the major source threshold for NOx in the nonattainment area. 

Sources with potential NOx emissions greater than 50 tons per year in the original 13-counties that 

were in operation before April 1, 2004, (existing sources) should have already been in compliance 

with the RACT requirements in the rule when the major source threshold dropped to 25 tons per 

year. 

For those sources with potential NOx emissions less than 50 tons per year in the original 13 counties 

that became subject to the rule when the threshold dropped to 25 tons per year and that were in 

operation before April 1, 2004 (existing sources), full compliance with their RACT demonstrations 

were required by May 1, 2007. 

For those sources in the six counties in the expanded area (Bartow, Carroll, Hall, Newton, Spalding, 

and Walton) that were in operation before October 1, 1999, full compliance with their approved 

RACT determination was required by May 1, 2003. Those that began operation after October 1, 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

13 

1999 were required to be in full compliance with their approved RACT determination immediately. 

Any new source in this 6-county area beginning operation after April 1, 2004, was required to be in 

full compliance with a case-by-case RACT demonstration upon startup. 

All sources subject to this rule in Barrow County were required to be in full compliance by March 1, 

2009. 

2.3.1.3 Georgia Rule (lll) 

Fuel burning equipment that is installed or modified after May 1, 1999 is regulated under Georgia 

Rule 391-3-1-.02(2)(lll) for NOx emissions. Georgia Rule (lll) established a compliance date for this 

standard beginning May 1, 2000 and it will affect all fuel burning equipment installed from that date 

forward. This rule only affects future possible emissions for new or modified sources by requiring 

the operation of equipment during the control season to meet emissions limits based on the use of 

natural gas. This measure is federally enforceable, however it is not necessary for the continued 

maintenance of the Atlanta NAA area. The implementation of this rule will support the maintenance 

of the ozone NAAQS for the Atlanta area. 

2.3.1.4 Georgia Rule (jjj) 

Coal-fired external combustion devices that generate steam for electricity generation are regulated 

under Georgia Rule 391-3-1-.02(2)(jjj) for NOx emissions. Georgia Rule (jjj) established a more 

stringent NOx emission standard beginning May 1, 2003. Georgia EPD estimated that NOx 

emissions from these point sources would be reduced by approximately 42% as a whole between 

2002 and 2009. The majority of NOx emissions from point sources come from coal-fired external 

combustion devices that generate steam for electricity generation. There are three such plants in the 

20-county metro Atlanta area and four such plants just outside the Atlanta NAA. 

2.3.1.5 Georgia Rule (rrr) 

Georgia Rule (rrr) is a RACT rule for small fuel-burning equipment that requires an annual tune-up 

and the burning of natural gas, LPG or propane during ozone season to reduce nitrogen oxide 

emissions. 

The deadline for full compliance with Georgia Rule (rrr) was May 15, 2005, in the original 13-

county nonattainment area and March 1, 2009, in the additional 7-county area. 

2.3.1.6 Georgia Rule (sss) Multipollutant Rule: NOx and SO2 Controls 

Coal-fired EGUs are by far the most significant point source of NOx and SO2 emissions in Georgia 

and in the southeast. Georgia’s Multipollutant Rule [391-3-1-.02(2)(sss)] requires selective catalytic 

reduction (SCR) and flue gas desulfurization (FGD) controls on all large coal-fired EGUs in 

Georgia. It was promulgated in 2007 for the purposes of lowering ozone and PM2.5 concentrations 

and reducing mercury deposition. The SCR controls reduced NOx emission rates by approximately 

85 percent and the FGD controls reduced SO2 emission rates from the affected emissions units by at 

least 95 percent. 

Figure 2-3 shows the locations of the coal-fired EGU facilities in the metro Atlanta nonattainment 

area as well as their respective energy production (in million megawatt-hours) in the year 2007 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

14 

before the control requirements went into effect. The facilities shown in the figure comprise three of 

the ten coal-fired EGU facilities that were operated in Georgia in 2007. In 2007, the energy 

produced by the three facilities made up 37 percent of the statewide energy production from coalfired facilities. 

Figure 2-2. Locations and 2007 energy production of coal-fired EGU facilities 

in the Atlanta NAA 

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

2009. Of these six units, which include Bowen Units 2, 3, and 4, Wansley Units 1 and 2, and 

Hammond Unit 4, only Bowen’s units are located in the metro Atlanta area. 

The schedule for the operation of SCRs on the remaining EGUs in the Atlanta NAA is as follows: 

 Bowen Unit 1 is required to operate an SCR year-round beginning in June 2010. 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

15 

 McDonough Unit 2 is required to operate an SCR year-round beginning in December 2011. 

 McDonough Unit 1 is required to operate an SCR year-round beginning in April 2012. 

 Plant Yates Units 6 and 7 are required to operate an SCR year-round beginning in June of 

2015. 

 Beginning in January of 2018, the remaining units at Plant Yates are required to be evaluated 

for additional mercury controls if the total annual heat input of those units combined exceeds 

33,608,398 million Btu. Any additional required controls could contribute to reduced NOx 

emissions. 

Georgia Rule (sss) has not been submitted to EPA for adoption into the SIP and is therefore not 

federally enforceable. The rule requirements to install and operate the control equipment have been 

incorporated into the each facility’s respective Title V Federal operating permit. The rule alone is not 

relied upon to meet continued maintenance; however, the rule was designed to meet the emission 

reductions and deadlines of the CAIR rule. Without the operation of the equipment required by Rule 

(sss), it would be impossible for the coal-fired EGUs operating in the state of Georgia to meet the 

emission budgets of either CAIR or the recently stayed Cross-State Air Pollution Rule (CSAPR). 

2.3.2 Federal Control Measures 

Federal control measures related to precursors of ambient ozone are also focused on the reduction of 

emissions associated with VOCs and NOx. 

VOCs 

Federal measures that targeted reduction of VOCs from stationary point sources include New Source 

Performance Standards (NSPS), National Emissions Standards for Hazardous Air Pollutants 

(NESHAPs), and Reasonably Available Control Technology (RACT). The State of Georgia has 

been delegated the authority to administer these measures. 

NOx 

Federal measures that targeted reduction of these emissions between nonattainment designation and 

the clean data period are as follows: 

 Clean Air Interstate Rule (CAIR) and Cross-State Air Pollution Rule (CSAPR); 

 Tier 2 Vehicle Standards; 

 Heavy-duty Gasoline and Diesel Highway Vehicles Standards & Ultra Low-Sulfur 

Diesel Rule; 

 Large Nonroad Diesel Engines Rule & Ultra Low-Sulfur Diesel Rule; 

 Non-Road Large 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. 

Detailed discussions of the measures are presented in the following subsections and implementation 

timetable is presented in Table 2-4. 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

16 

Table 2-4. Timetable of Federal NOx Measure Implementation 

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 

Ozone 4th Max GA National Guard 

McCollum 

Parkway 0.088 0.100 0.084 0.073 0.081 0.093 0.089 0.079 0.076 0.079 

University of W. 

Georgia at Newnan 0.085 0.099 0.077 0.083 0.078 0.086 0.091 0.075 0.065 0.065 

2390-B Wildcat 

Road Decatur, GA 0.085 0.095 0.083 0.084 0.087 0.096 0.096 0.087 0.077 0.075 

Douglasville W. 

Strickland St. 0.092 0.098 0.085 0.080 0.089 0.095 0.086 0.080 0.072 0.074 

Gwinnett Tech 

1250 Atkinson Rd. 0.080 0.089 0.088 0.092 0.082 0.096 0.092 0.081 0.073 0.072 

Henry County 

Extension Office 0.086 0.099 0.082 0.085 0.089 0.095 0.102 0.086 0.074 0.078 

Yorkville 0.085 0.099 0.083 0.073 0.082 0.084 0.085 0.073 0.067 0.071 

Conyers Monastery 

3780 GA Hwy. 212 0.091 0.099 0.078 0.087 0.088 0.099 0.095 0.090 0.070 0.076 

Confederate Ave. 0.084 0.100 0.091 0.089 0.092 0.092 0.086 0.086 0.077 0.080 

Fayetteville – 

GDOT 0.099 0.091 0.083 0.083 0.082 0.087 0.090 0.086 ---* ---* 

Measure Pollutants 

Controlled 

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 

Cross-State Air 

Pollution Rule 

NOx X X 

Tier 2 vehicle 

standards 

NOx X X X X X X 

Heavy Duty Vehicle 

Standard 

NOx, VOC X X X X X X 

Large Nonroad 

Diesel Engines Rule 

NOx, PM X X 

Nonroad Spark 

Ignition and 

Recreational Vehicle 

NOx, VOC, CO X X X X X X 

NOx SIP Call in 

Surrounding States 

NOx X X X X X X 

*Temporarily discontinued as detailed in EPD’s Ambient Air Monitoring Plan approved by EPA 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

17 

2.3.2.1 Clean Air Interstate Rule and Cross-State Air Pollution 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 matter 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 planned 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. 

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 become effective in 2012 and 2014. These requirements take effect beyond the 2008-2010 

clean data period for metro Atlanta, but will nevertheless result in additional NOx emission 

reductions from EGUs in the future. 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. 

2.3.2.2 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 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 to be 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. 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

18 

2.3.2.3 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. 

2.3.2.4 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 

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. 

2.3.2.5 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 standard applies to all new engines sold 

in the United States and imported after these standards began and applies 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. 

2.3.2.6 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 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

19 

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. 

2.4 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, the Atlanta area was designated as nonattainment for the 1997 

8-hour ozone standard on April 30, 2004. 

Georgia EPD submitted an ozone attainment demonstration plan for the Atlanta NAA per Title I Part 

D of the CAA. With the determination that the metro Atlanta nonattainment area has attained the 

1997 8-hour ozone NAAQS, the area is no longer subject to the nonattainment provisions of Section 

110 and Part D requirements for demonstrating attainment, RFP, and contingency for areas 

designated as nonattainment with the NAAQS [76 FR 36873]. Therefore, the nonattainment plan 

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

Atlanta area have previously been approved or are currently subject to approval by EPA. 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

20 

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 (ozone, in this case) and contingency provisions for prompt 

implementation 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 2024. 

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 attainment year inventory. Emissions 

projections are formulated for the final year of the maintenance period (maintenance inventory) 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 ozone season summer day 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. 

3.1.1 Attainment Year Emissions Inventory 

Ozone season daily emissions for ozone precursors (VOC and NOx) in the Atlanta ozone 

nonattainment area were developed for attainment year 2008 and future years 2017 and 2024. Most 

of the 2008 attainment year annual emissions were obtained from the National Emissions Inventory 

2008 Version 1.5 (NEI2008, http://www.epa.gov/ttnchie1/net/2008inventory.html). The attainment 

year emissions were projected to future years separately using different methods by seven source 

categories, including: 

 

3

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

Calcagni, Director, Air Quality Management Division, OAQPS, USEPA 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

21 

 EGU point sources; 

 Non-EGU point sources; 

 Area sources; 

 Fires; 

 Nonroad mobile sources; 

 Nonroad mobile sources - Marine, aircraft and railroad; and 

 Onroad mobile sources. 

Ozone season daily emissions were calculated as the average daily emissions during the period of 

June, July and August. The Atlanta ozone nonattainment area covers 20 counties. 

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 B and Appendices B-1 through B-7. 

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 EPD 2011 Georgia DOT [travel demand 

model and Highway 

Performance Monitoring 

System (HPMS)] 

Nonroad Mobile SEMAP Final Report, 2010 NMIM2008, 2007 NMIM 

County Database, 2008 NEI, 

ERTAC 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

22 

3.1.1.1 Point Sources 

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

exceed 25 tons per year of VOC or NOx in the original 13 counties (Cherokee, Clayton, Cobb, 

Coweta, DeKalb, Douglas, Fayette, Forsyth, Fulton, Gwinnett, Henry, Paulding, and Rockdale), and 

100 tons per year of VOC or NOx in the seven new counties (Barrow, Bartow, Carroll, Hall, Newton, 

Spalding, and Walton). Emissions from point sources have been calculated for EGU and non-EGU 

sources. 

EGU Point Sources: 

Process-level emissions estimates for three EGU facilities in Atlanta ozone nonattainment area 

during 2008 were obtained from NEI2008 Version 1.5. The emissions were projected to year 2017 

and 2024 using corresponding growth and control factors. 

Ozone season daily emissions for EGU point sources were calculated by multiplying the annual total 

emissions with daily emissions fractions during June, July and August. The fractions for NOx and 

VOC emissions during June, July and August were estimated, respectively, using hourly 2008 

CAMD CEM NOx emissions and heat input data, and then were divided by the number of days in 

these three months (92) to get ozone season daily emissions fractions. The same daily fractions have 

been used for both attainment year and future years. For future year emissions from Plant 

McDonough-Atkinson, the fraction of NOx emissions during the months of June through August was 

calculated as the product of the NOx ozone-season limit and three months divided by the sum of the 

ozone-season limit times five months and the non-ozone season limit times seven months. 

Ozone season daily emissions during 2008, 2017 and 2024 were summarized by each EGU facility 

(Table 3-2). 

Table 3-2. Ozone Season Daily Emissions by EGU facilities in 2008, 2017 and 2024, 

tons/day 

Facility Name AIRSID 2008 2017 2024 

 VOC NOX VOC NOX VOC NOX 

GA Power Company - Plant Bowen 01500011 1.06 18.99 1.12 19.46 1.17 20.22 

GA Power Company - Plant 

McDonough/Atkinson 06700003 0.14 10.04 0.78 1.19 0.93 1.41 

GA Power Company - Plant Yates 07700001 0.37 34.59 0.38 18.57 0.40 19.29 

Total 1.57 63.62 2.29 39.22 2.50 40.92 

Non-EGU Point Sources: 

Appendix B-3 contains a list of non-EGU point sources in Atlanta ozone nonattainment area and 

facility-specific VOC and NOx ozone season daily emissions for 2008, 2017, and 2024. 

Transcontinental Gas Pipe Line Company, LLC – Compressor Station 120 in Henry County is by far 

the largest single summer day non-EGU point source of both NOx and VOC emissions in the metro 

Atlanta nonattainment area with 5.91 tons per day of NOx and 1.04 tons per day of VOC. Please see 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

23 

the previously mentioned list in Appendix B-3 for information on the other non-EGU point sources 

in the metro Atlanta area. 

2008 ozone season summer-day emissions of NOx and VOC from EGU and non-EGU facilities are 

presented in Table 3-3.

Table 3-3. Point Source Emissions for 2008 (tons, summer day) 

Pollutant EGU Point 

Source 

Emissions 

Non-EGU 

Point Source 

Emissions 

Total Point 

Source 

Emissions 

NOx 63.62 12.37 75.99 

VOC 1.57 12.22 13.79 

Emissions estimates for non-EGU point sources in 2008 were obtained from NEI2008 Version 1.5. 

Emissions in future years 2017 and 2024 were estimated using SCC- and county-specific growth 

factors generated with the U.S. EPA’s Economic Growth Analysis System Version 5.0 (EGAS 5.0) 

with "Default REMI 6.0 SCC Configuration." Appendix B-2 contains a summary of the SCCspecific growth factors for Atlanta ozone nonattainment area. These emissions are not subject to 

additional controls in the future years 2017 and 2024. 

Ozone season daily emissions for non-EGU point sources were estimated by multiplying the annual 

total emissions with ozone season daily emissions fractions, which were calculated using the same 

temporal allocation method used in Sparse Matrix Operator Kernel Emissions (SMOKE, 

http://www.smoke-model.org/index.cfm). The SMOKE temporal profiles and reference files were 

obtained from EPA’s 2005 Modeling Platform website 

(ftp://ftp.epa.gov/EmisInventory/2005v4_2/ancillary_smoke). The SMOKE temporal profiles gave 

monthly emissions fractions, and were linked to each emission record by SCC according to the 

SMOKE temporal reference file. The total of the monthly fractions of June, July and August were 

divided by the number of days in these three months (92) to get ozone season daily emissions 

fractions. 

3.1.1.2 Nonpoint Sources 

Area Sources: 

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

NOx, SO2, and particulate matter are each less than 25 tons per year. Emissions from nonpoint 

sources in 2008 were obtained from NEI2008 version 1.5. Ozone season daily emissions for area 

sources were calculated using the SMOKE temporal profiles as described for non-EGU point 

sources. 

Appendix B-2 contains SCC-specific VOC and NOx ozone season daily emissions for 2008, 2017, 

and 2024. 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

24 

Fires: 

Emissions from fires in 2008 were obtained from NEI2008 version 1.5. These estimates were 

provided by Georgia Environmental Protection Division as part of AERR2008 submission (Georgia 

Air Protection Branch, 2011). This inventory was developed using 2008 burned area data and 

burning permit data provided by Georgia Forestry Commission and the same method as used for the 

VISTAS2002 fire inventory (www.epa.gov/ttnchie1/conference/ei13/rpo/barnard_pres.pdf). 

Emissions in future years 2017 and 2024 were assumed to be the same as attainment year 2008. 

Ozone season daily emissions for fires were calculated by dividing the total emissions during June, 

July and August by the number of days in these three months (92). The emissions during these three 

months were estimated using monthly emissions for nonpoint fires and event emissions records for 

wildfires occurred during this period in NEI2008. 

Appendix B-3 contains VOC and NOx ozone season daily emissions summary by fire types and 

county in Atlanta ozone nonattainment area for 2008, 2017, and 2024. 

The 2008 nonpoint source ozone season summer day emissions for the metro Atlanta area are 

presented in Table 3-4. 

Table 3-4. Nonpoint Source Emissions for 2008 (tons, summer day) 

Pollutant Nonpoint 

(excluding fire) 

Fire Total 

Nonpoint 

NOx 49.30 0.00 49.30 

VOC 216.46 0.01 216.47 

3.1.1.3 Onroad Mobile Sources 

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

2008 on-road mobile source emissions of NOx, VOC, and PM. The following non-default inputs to 

the 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 2008 using 

a combination of Georgia Department of Revenue registration data (for buses and motorcycles) and 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

25 

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

types). The 2008 weekday VMT were from Georgia DOT's "445 Report" estimate of daily 2008 

VMT by county.4

 The 2008 weekend VMT were from MOVES default inputs. 

Actual 2008 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 2008. For a detailed discussion on how the on-road mobile emission inventory 

was developed, see Appendix B-7. A summary of the 2008 on-road mobile source emissions is as 

follows: 

 NOx 364.02 tons per day, and 

 VOC 165.53 tons per day. 

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. 

Emissions from aircrafts and locomotives in 2008 were obtained from NEI2008 version 1.5 

(http://www.epa.gov/ttnchie1/net/2008inventory.html). Emissions from yard locomotives were not 

included in the NEI2008, and were obtained from Eastern Regional Technical Advisory Committee 

(ERTAC) separately (personal communication with Dr. Michelle Bergin on 9/14/2011). There were 

no emissions from commercial marine vessels in the Atlanta ozone nonattainment area. 

Table 3-5. Nonroad Mobile Source Emissions for 2008 (tons, ozone season summer 

day) 

Pollutant 

(tons) 

Nonroad - 

except air and 

rail

Aircraft Locomotive Total 

Nonroad

NOx 71.96 29.77 15.74 117.47 

VOC 88.11 7.05 0.87 96.03 

3.1.1.5 Summary of 2008 Emissions Inventory 

The total 2008 Atlanta NAA emissions of NOx, and VOC are presented for each source sector in 

Table 3-6. The majority of NOx emissions is from onroad mobile sources and nonroad mobile 

sources. The majority of VOC emissions is from onroad mobile sources and nonpoint sources. 

 

4

 http://www.dot.state.ga.us/statistics/RoadData/Pages/400Series.aspx 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

26 

Table 3-6. Attainment-year (2008) Emissions Inventory (tons, summer day)

Pollutant 

(tons) 

Point 

Total 

Point 

EGU 

Point 

NonEGU 

Nonpoint Onroad 

Mobile 

Nonroad 

Mobile 

Total 

NOx 75.99 63.62 12.37 49.30 364.02 117.47 606.78

VOC 13.79 1.57 12.22 216.47 165.53 96.03 491.82

3.1.2 Emissions Projections 

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

2024 (maintenance year). Emissions projections to support maintenance through 2024 have been 

prepared for the years 2017 and 2024. 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, projected inventories, and the maintenance safety margin 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 2008 emissions of individual sources or source categories. The control and growth factors may 

apply for some or all of the years 2008 (attainment inventory) through 2024 (out year). The basis 

used to determine these factors are summarized in Table 3-7. 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

27 

Table 3-7. Basis 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 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

28 

The pollutants whose emissions are projected are NOx, and VOC. 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, and 

 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 B and Appendices B-1 through B7. 

3.1.2.1.1 Point Sources 

EGU Point Source: 

EGU point source emissions in 2017 and 2024 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. Selective Catalytic Reduction (SCR) for 

control of NOx was applied to individual units according to the schedule specified in Georgia’s Rule 

391-3-1-.02(2)(sss). The dates of initial SCR operation required by the rule for the EGUs inside the 

nonattainment area range from December 31, 2008, through June 1, 2015. Plant Bowen, Plant 

McDonough, and Plant Yates are the three electric generation facilities inside the nonattainment area. 

Plant Bowen has four EGUs, McDonough has two EGUs and Plant Yates has seven EGUs. Units at 

Bowen actually began ozone-season SCR operation prior to 2008. Please refer to Appendix B-1 for 

detailed EGU control schedules. 

Table 3-8. Growth factors by SCCs for EGU sources 

SCC Fuel Type 2017 2024 

20100101 Distillate Fuel Oil 1.352 1.447

10100501 Distillate Fuel Oil 1.352 1.447

20100201 Natural Gas 0.892 1.060

10100604 Natural Gas 0.892 1.060

10100212 Steam Coal 1.058 1.099

The NOx control factor associated with SCR control was assumed to be 82.5% according to the 

VISTAS 2012 Projection Emissions Inventory. When SCR control was already operated fully or 

partially at a unit during year 2008, the control factor was applied only to uncontrolled NOx 

emissions that occurred in 2008. These periods were identified using CAMD hourly CEM data for 

NOx emissions and heat inputs. Days without SCR operation were identified as those days on which 

the ratio of NOx emissions to heat input exceeded 0.00004 lbs/Btu, according to correlation analysis 

results. In addition, NOx emissions during the period from October 1st, 2008, to December 31st, 

2008, from Plant Bowen Unit 3 were projected to future years using a different method, since the 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

29 

actual NOx control efficiency in this period was approximately 60% according to hourly CEM data 

analysis. Such NOx emissions were first adjusted to reflect before control emissions, then apply the 

82.5% NOx emissions control factor for future year emissions projection. 

Future year emissions for Plant McDonough-Atkinson located in Cobb County were calculated 

separately since this plant will undergo significant changes in generating equipment and operation 

during the attainment demonstration period. In 2008, Plant McDonough operated two coal-fired 

EGUs (Units 1 and 2) with a combined generating capacity of 530 MW. Due to the requirements 

specified in Georgia’s Rule 391-3-1-.02(2)(sss) for EGU controls, Georgia Power plans to shut down 

Unit 2 by the fourth quarter of 2011 and Unit 1 by the second quarter of 2012. Unit 2 will be 

replaced with two gas-fired combined cycle blocks (Blocks 4 and 5) and Unit 1 will be replaced by 

one gas-fired combined cycle block (Block 6). Each block consists of two generating units, with 

each unit consisting of a combustion turbine and a duct burner. The combined generation capacity of 

the three blocks (six units) is 2,520 MW. NOx emissions from each unit will be controlled by an 

SCR and a low-NOx burner. 

The facility’s Title V permit (Permit No. 4911-067-0003-V-03-0) stipulates rolling 12-month limits 

on NOx and VOC emissions from each of the three gas-fired generating blocks. In addition, shortterm average NOx and VOC emissions rates (in ppmvd) are stipulated for both the ozone and nonozone seasons. The 12-month per block limits for Blocks 4 and 5 are 135 tons VOC and 217 tons 

NOx. The limits for Block 6 are 132 tons VOC and 200 tons NOx. The permitted NOx emission 

rates are 6.0 ppmvd for May through September and 15.0 ppmvd for the rest of the year. 

Forecasts of NOx and VOC emissions from McDonough’s Blocks 4, 5, and 6 were calculated by 

assuming that actual rolling 12-month emissions will be 75 percent of the permitted limits. It is 

assumed that the duration of operation for these gas-fired units will not push NOx and VOC 

emissions beyond 75 percent of their twelve-month permit caps. Growth factors were calculated for 

McDonough-Atkinson using the same fuel consumption approach that is described above, subject to 

the constraint that annual emissions cannot rise above the permitted 12-month limits. 

Georgia has been identified as a state covered under EPA’s Cross-State Air Pollution Rule, which 

requires covered states to comply with state-wide allocations of NOx and/or SO2 emissions from 

covered EGUs starting in 2012. Georgia is required to comply with state budgets for annual NOx, 

ozone-season NOx, and annual SO2 emissions. Georgia and affected EGU owner/operators are 

currently developing a strategy for complying with the rule. The effect of the rule on emissions 

levels from EGUs in the metro Atlanta area is not known at this time and, therefore, has not been 

incorporated into the emissions projections. Any further reductions that may 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 3-9. The projections show a reduction 

in NOx emissions but a small increase in VOC emissions. Emissions levels for 2014 were calculated 

by linear interpolation between 2008 and 2017. Emissions levels for 2020 were calculated by linear 

interpolation between 2017 and 2024. 

Non-EGU Point Source: 

Projected non-EGU point source emissions are also shown in Table 3-9. The emissions for 2017 and 

2024 were estimated using SCC-specific and county-specific growth factors generated with EPA’s 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

30 

Economic Growth Analysis System Version 5.0 (EGAS 5.0) with “Default REMI 6.0 SCC 

Configuration.” The projections show moderate increases in emissions of all three pollutants. 

Appendix B-2 contains a summary of the SCC-specific growth factors for the metro Atlanta area. 

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.

Projected total point source emissions (sum of EGU and non-EGU) are also shown in Table 3-9. The 

projections show moderate decreases in emissions of NOx, but a minor increase in VOCs overall. 

Table 3-9. Projected Point Source Emissions (tons, summer day) 

Pollutant 2008 

(attainment)

2014 2017 2020 2024 

 

EGU 

NOx 63.62 47.35 39.22 39.95 40.92 

VOC 1.57 2.05 2.29 2.38 2.50 

Non-EGU 

NOx 12.37 13.35 13.83 14.48 15.35 

VOC 12.22 13.75 14.52 15.42 16.63 

 

Total Point 

NOx 75.99 60.69 53.05 54.43 56.27 

VOC 13.79 15.80 16.81 17.80 19.13 

3.1.2.1.2 Nonpoint Sources 

Emissions in future years 2017 and 2024 were estimated using SCC- and county-specific growth 

factors generated with the U.S. EPA’s Economic Growth Analysis System Version 5.0 (EGAS 5.0) 

with "Default REMI 6.0 SCC Configuration." Appendix B-2 contains a summary of the SCCspecific growth factors for the Atlanta ozone nonattainment area. No additional future controls can 

be defined for these sources at this time. 

Projections of nonpoint source emissions are presented in Table 3-10. Emissions from fire in future 

years 2017 and 2024 were assumed to be the same as 2008 emissions. The projections show a 

moderate increase in emissions of NOx as well as VOC. 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

31 

Table 3-10. Projected Nonpoint Source Emissions (tons, summer day) 

Pollutant 2008 

(attainment)

2014 2017 2020 2024 

 

Nonpoint 

(excluding fire) 

 

NOx 49.30 54.92 57.73 60.62 64.48 

VOC 216.46 243.28 256.69 270.61 289.16 

 

Fire 

NOx 0.0035 0.0035 0.0035 0.0035 0.0035 

VOC 0.0149 0.0149 0.0149 0.0149 0.0149 

 

Total Nonpoint 

NOx 49.30 54.92 57.73 60.63 64.48 

VOC 216.47 243.30 256.70 270.62 289.17 

3.1.2.1.3 Onroad mobile sources 

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

2024 onroad mobile source emissions of NOx, and VOC. Intermediate year emissions were 

generated by interpolating between 2008 and 2024. The following non-default inputs to the model 

were used: 

 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 & Company registration data. Defaults were 

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

area were used to calculate the 2024 vehicle population. The 2024 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 2008.
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

32 

The projected onroad mobile source emissions levels are presented in Table 3-11. Onroad emissions 

of both pollutants trend downward significantly during the maintenance period. For a detailed 

discussion on how the onroad mobile emission inventory was developed, see Appendix B-7. 

Table 3-11. Projected Onroad Mobile Source Emissions (tons, summer day) 

Pollutant 

(tons) 

2008 

(attainment)

2014 2017 2020 2024 

 

NOx 364.02 264.80 215.19 165.58 99.43 

VOC 165.53 126.92 107.61 88.30 62.56 

3.1.2.1.4 Nonroad mobile sources 

Growth and control factors that were used to develop future year emissions were provided by 

Pechan. For more information regarding the SEMAP marine, aircraft, and locomotives growth and 

control factors, please refer to Appendix B-5. (Pechan, 2011) 

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 (TAF). (FAA, 2010) Growth rates for military aircraft were held constant at 2008 levels. 

No control factors were applied to aircraft for criteria pollutant forecasts. 

Growth factors for Class I and Class II/III line haul and diesel switchyard operations were calculated 

based on freight rail sector fuel consumption forecasts. Growth factors for passenger and commuter 

rail were developed from national forecasts of intercity rail diesel consumption, and commuter rail 

diesel consumption. Control factors were based on US EPA’s locomotive engine Regulatory Impact 

Analyses (RIA) and associated emission factor guidance. 

The SEMAP growth factors were for base year 2007 (referred as hereafter). The growth 

factors for base year 2008 ( ) were calculated as assuming linear 

growth. refers to the number of years between base year 2007 and future years. is 10 

years for future year 2017 and is 17 years for future year 2024. 

Ozone season daily emissions for aircrafts and locomotives were calculated using the SMOKE 

temporal profiles as described for non-EGU point sources. 

Appendix B-6 contains a list of specific aircraft and locomotives sources in Atlanta ozone 

nonattainment area and SCC-specific VOC and NOx emissions for 2008, 2017, and 2024 and the 

associated growth or control factors. 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

33 

The nonroad mobile source emissions projections are presented in Table 3-12. The projections show 

a moderate decrease in emissions of both NOx and VOC. 

 

Table 3-12. Projected Nonroad Mobile Source Emissions (tons) 

Pollutant 

(tons) 

2008 

(attainment) 

2014* 2017 2020* 2024 

 

Nonroad** 

NOx 71.99 42.36 30.87 

VOC 88.11 55.33 52.64 

 

Aircraft 

NOx 29.77 36.71 43.79 

VOC 7.05 8.28 9.70 

 

Locomotive 

NOx 15.74 10.97 8.35 

VOC 0.87 0.50 0.35 

 

Tot. Nonroad 

NOx 117.47 99.18 90.04 87.03 83.01 

VOC 96.03 74.75 64.11 63.50 62.69 

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

** excluding aircraft and locomotive emissions 

3.1.2.1.5 Emissions Projections Summary and Demonstration of Maintenance of Attainment 

The consolidated emissions projections for all metro Atlanta sources are presented in Table 3-13. 

Emissions of NOx and VOC drop significantly from 2008 to 2024. Overall, emissions of NOx and 

VOC are projected to decline by almost 50 percent and 12 percent, respectively, over the course of 

the maintenance period.

Table 3-13. Projected Emissions – Total of All Sectors (tons, summer day) 

Pollutant 

(tons) 

2008 

(attainment)

2014 2017 2020 2024 

 

NOx 606.78 479.60 416.01 367.67 303.19

VOC 491.82 460.76 445.23 440.23 433.55
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

34 

3.1.2.2 Emissions Decreases 

The degree of improvement (reduction) in 2024 emissions compared to the attainment year (2008) 

emissions can be used to determine the amount of emission that can be allocated as safety margin for 

the area’s motor vehicle emissions budget. The decrease in emissions of NOx and VOC from 2024 

to 2008 is shown in Table 3-14. Only a portion of the NOx (and VOC) margin will be allotted to the 

Motor Vehicle Emissions Budget (see Section 4). 

 

Table 3-14. Emissions Decreases 

Pollutant Emissions 

Decrease* 

2008 to 2024 

(tons) 

NOx ** 303.59

VOC ** 58.27

* Decrease in Emissions = (2008 emissions level) – (2024 emissions level) 

** These quantities do not reflect allotment to Motor Vehicle Emissions Budget 

3.1.3 Verification of Continued Attainment 

Verification of continued attainment is accomplished through operation of the ambient ozone 

monitoring network and the periodic updates of the area's emissions inventory. EPD will continue to 

operate the current monitors located in the metro Atlanta area. There are no plans to discontinue 

operation, relocate, or otherwise change the existing ambient monitoring network. 

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 three-year cycle. 

The inventory will be updated and maintained on a three-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 that 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: 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

35 

 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 8-hour ozone 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 Atlanta 8-hour ozone nonattainment area. 

Contingency measures are intended to provide further emission reductions in the event that 

violations of the 8-hour ozone 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 violations of the 8-hour ozone NAAQS occur within the Atlanta 

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 

ozone monitoring data that indicates a violation of the ozone 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 8-hour ozone NAAQS be violated, or if emissions 

in the Atlanta maintenance area increase significantly above current levels. 

Tier I. A Tier I trigger is activated when any quality-assured 8-hour ozone monitoring reading 

exceeds 0.084 ppm at an ambient monitoring station located in the Atlanta maintenance area or if the 

periodic emission inventory updates reveal excessive or unanticipated growth greater than 10% in 

emissions of either ozone precursor over the attainment or intermediate emissions inventories for the 

Atlanta maintenance area (as determined by the triennial emission reporting required by AERR). 

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 ozone trigger concentrations described above apply to each 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 ozone 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 8-hour ozone NAAQS at any of the 

metro Atlanta ambient monitoring stations in the Atlanta maintenance area is recorded, based on 

quality-assured monitoring data. In this event, EPD will conduct a comprehensive study to 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

36 

determine the cause(s) of the ambient ozone 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 ozone standard. Since 

the metro Atlanta area 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: 

 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) NOx controls]; and 

 current and recently identified control technologies. 

The comprehensive study will be completed and submitted to EPA as expeditiously as practical but 

no later 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 the maintenance of the ozone 

standard, 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 ozone precursors in excess of what is relied upon in this maintenance plan, 

includes the Georgia Multipollutant Rule, which is mentioned in section 2.3.1.5 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 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

37 

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 VOC and NOx. 

 Reasonably Available Control Technology (RACT) for point sources of VOC and NOx, 

specifically the adoption of new and revised RACT rules based on Groups II, III, and IV 

CTGs. 

 Expansion of RACM/RACT to area(s) of transport within the State. 

 Mobile Source Measures 

 Additional NOx reduction measures yet to be identified. 

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 publication of 

notices, an opportunity for public hearing, and other measures required by Georgia law. 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

38 

4.0 Motor Vehicle Emissions Budget 

The transportation conformity rule (40 CFR 93.100 - 40 CFR 93.129) 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 40 CFR 93.124(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 metro Atlanta, MVEBs will be set for direct NOx and VOC only. 40 CFR Parts 93.119(f)(1) 

through (10) identify the ozone pollutants which must be analyzed for transportation conformity 

purposes. These parts of the rule are listed below: 

§119(f)(1) - VOC in ozone areas; and 

§119(f)(2) - NOx in ozone areas, unless the EPA Administrator determines that additional reductions 

in NOx would not contribute to attainment. 

4.2 Methodology 

In preparation of this Atlanta Area Ozone Maintenance Plan, EPD worked closely with the Georgia 

Department of Transportation (GDOT) and the Atlanta Regional Commission (ARC) to develop the 

estimates of mobile source emissions for the Atlanta nonattainment area. ARC is the metropolitan 

planning organization (MPO) for Metro Atlanta Area. Mobile source inventories for 2024 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 2024 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 Appendix B-7 for more details on the development of 

the travel demand model and the determination of emissions factors. 

The MOVES2010a motor vehicle emissions model was used to calculate 2024 emission factors with 

all currently known 2024 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 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

39 

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. 

The ARC 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 40 CFR 93.122(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 ARC. 

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 ARC interagency 

consultation committee for review on September 15, 2011. The assumptions used to develop metro 

Atlanta’s conforming Long Range Transportation Plan and Transportation Improvement Program 

were also used to develop the network and emissions for this maintenance plan MVEB. 

4.3 Motor Vehicle Emissions Budgets and Safety Margins 

The projected 2024 on-road motor vehicle emissions for NOx and VOC are 99.43 and 62.56 tons per 

day, respectively. As presented in Section 3.1.2.2, the overall surplus or overall emissions reduction 

from 2008 for all sectors is 302.79 tons per day for NOx and 58.84 tons per day for VOCs. A portion 

of these emission reductions will be used as a safety margin for the MVEB. The safety margin 

needed is based on determining a worst-case daily emissions projection. 

The worst-case daily motor vehicle emissions projection for NOx is 27 percent above the projected 

2024 on-road emissions. In a worst-case scenario, the needed safety margin for the MVEB would be 

26.9 tons per day resulting in an overall MVEB of 126 tons per day. 

The worst-case daily motor vehicle emissions projection for VOC is 47 percent above the projected 

2024 on-road emissions. In a worst-case scenario, the needed safety margin for the MVEB would be 

29.4 tons per day resulting in an overall MVEB of 92 tons per day. 

The projected 2024 on-road emissions, the emissions budgets, and safety margins are presented in 

Table 4-1. The additional emission allotted for the safety margin is added to the overall inventory as 

presented in Table 5-1. 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

40 

Table 4-1. Motor vehicle projected emissions, safety margins and emissions budgets 

Pollutant Projected 2024 

On-Road 

Emissions (tons 

per day) 

Safety Margin 

Allotted to MVEB 

(%) 

Safety Margin 

Allotted to 

MVEB (tons 

per day) 

MVEB with Safety 

Margin included 

(tons per day) 

NOx 99.43 27 26.9 126 

VOC 62.56 47 29.4 92 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

41 

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 NOx Emissions – Total of All Sectors (tons, summer 

day) 

Source 

2008 

attainment

(tons/ day) 

2014 

(tons/ day) 

2017 

(tons/ day) 

2020 

(tons/ day) 

2024

(tons/ day) 

Point - total 75.99 60.69 53.05 54.43 56.27 

Area - total 49.30 54.92 57.73 60.63 64.48 

Non-road - total 117.47 99.18 90.04 87.03 83.01 

Onroad 364.02 264.80 215.19 165.58 99.43 

Onroad Safety Margin 26.90 

Total 606.78 479.60 416.01 367.66 330.09 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

42 

Table 5-2. Summary of Projected VOC Emissions – Total of All Sectors (tons, summer 

day) 

Source 

2008 

attainment 

(tons/ day) 

2014 

(tons/ day) 

2017 

(tons/ day) 

2020 

(tons/ day) 

2024 

(tons/ day) 

Point - total 13.79 15.80 16.81 17.80 19.13

Area - total 216.47 243.29 256.70 270.62 289.17

Non-road - total 96.03 74.75 64.11 63.50 62.69

Onroad 165.53 126.92 107.61 88.30 62.56

Onroad Safety Margin 29.40

Total 491.82 460.76 445.23 440.23 462.95

 

The supporting documentation to show that the above conditions have been met for metro Atlanta is 

contained in this document. Based on the 2008-2010 monitored design values for the Atlanta 

nonattainment area, EPA has published in the Federal Register a determination that the Atlanta, 

Georgia 1997 8-hour ozone nonattainment area has attained the standard [76 FR 36873]. 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 2024. 

This document also contains provisions for contingency measures should emissions levels or 

ambient concentrations rise unexpectedly. EPA’s concurrence that the improvement in the metro 

Atlanta area’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 metro Atlanta nonattainment area be redesignated to attainment with respect to the 1997 8-hour 

ozone NAAQS. 
Georgia’s Redesignation Request and Maintenance Plan for the Atlanta Ozone 

Nonattainment Area for the 1997 8-Hour Ozone NAAQS 

43 

6.0 References 

State of Georgia, Rules for Air Quality Control, Chapter 391-3-1, Effective September 13, 2011. 

USEPA, “Reasonable Further Progress, Attainment Demonstration, and Related Requirements for 

Ozone Nonattainment Areas Meeting the Ozone National Ambient Air Quality Standard,” 

Memorandum from John S. Seitz, May 10, 1995. 

USEPA, “Determination of Attainment for the 1997 Ozone Standard; Atlanta, Georgia, Final Rule”; 

76 FR 36874 – 36875. 

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. 

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, “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. 

US Energy Information Administration, Annual Energy Outlook 2010, April 2010.