Georgia's Redesignation Request and 

Maintenance Plan for the Chattanooga 

Nonattainrnent Area for the 1997 PM2.5 NAAQS 

For Catoosa and Walker Counties 

August 31, 2012 

Prepared by: 

Georgia Department of Natural Resources 

Environmental Protection Division 

Air Protection Branch 
Georgia Portion of the Chattanooga PM2.5 NonuttainmentAreu 

Redesignation Request und Maintenance Plan 

Executive Summary 

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

the Georgia portion of the Chattanooga nonattainment area be redesignated to attainment with 

respect to the annual National Ambient Air Quality Standard (NAAQS) for PM25 (1997 fine 

patticulate matter standard, retained -in 2006). The document also includes Georgia's plan to 

maintain attainment of the PM2.

5 standard in Catoosa and Walker counties. The Georgia 

Environmental Protection Division has developed its own separate maintenance plan for the Georgia 

pottion of the Chattanooga PM2_5 nonattainment area. 

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

the standard (15 .0 ftg/m3

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

implementation of petmanent and enforceable reductions in PM2.5 and PM25 precm·sor emissions; 

compliance with all applicable requirements; and the Georgia Pottion of Chattanooga Maintenance 

Plan with projections demonstrating maintenance of the standard through the year 2025. 
Georgia Portion of the Chattanooga PM2.5 NonattainmentArea 

Redesignation Request and Maintenance Plan 

TABLE OF CONTENTS 

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

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

1.1 Nonattainment Designation and Attainment Demonstration .......................................... ! 

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

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

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

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

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

2.1.2 Ambient PM25 Data ........................................................................................................................ 6 

2.1.3 Clean Data Determination ............................................................................................................... 7 

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

2.3 Permanent and Enforceable and Other Reductions in Emissions .................................. 8 

2.3 .I Source Apportionment of Ambient PM25 ....................................................................................... 8 

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

2.3.2.1 S02 and NOx Controls and S02 Limits ................................................................................ I 0 

2.3.2.2 Smoke Management Plan ..................................................................................................... l6 

2.3.3 Federal Control Measures ............................................................................................................. 17 

2.3.3.1 Clean Air Interstate Rule ...................................................................................................... 18 

2.3.3.2 Tier 2 Vehicle Standards and Low-Sulfur Gasoline ............................................................. l9 

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

Rule ........................................................................................................................................ 20 

2.3.3.4 Large Nonroad Diesel Engines Rule & Ultra Low-Sulfur Diesel Rule ................................ 20 

2.3.3.5 Nonroad Large Spark-Ignition Engines and Recreational Engines Standard ....................... 20 

2.3.3.6 NO, SIP Call in Sunounding States ..................................................................................... 21 

2.3.4 S02 Emissions Reductions in Upwind States ................................................................................ 21 

2.4 Section 110 and Pa11 D Requirements ............................................................................. 24 

3.0 Maintenance Plan ...................................................................................................... 25 

3.1 Maintenance Demonstration ............................................................................................ 25 

3.1.1 Attainment Year Emissions Inventory .......................................................................................... 25 

3.1.1.1 PointSources ........................................................................................................................ 27 

3.1.1.2 Nonpoint Sources ................................................................................................................. 27 

3.1.1.3 Onroad Mobile Sources ........................................................................................................ 29 

3.1.1.4 Nonroad Mobile Sources ...................................................................................................... 29 

3.1.1.5 Summary of2007 Emissions Inventmy ............................................................................... 30 

3.1.2 Projected Emissions Inventories ................................................................................................... 30 

3.1.2.1 Methods and Projected Inventories ...................................................................................... 3 l 

3.1.2.2 Point Sources ........................................................................................................................ 32 

3.1.2.3 Nonpoint Sources ................................................................................................................. 32 

3 .1.2.4 Onroad Mobile Sources ........................................................................................................ 34 

3.1.2.5 Nonroad Mobile Sources ...................................................................................................... 34 

3.1.3 Emissions Projections Summary and Demonstration of Maintenance of Attainment.. ................. 35 

3.1.4 Emissions Decreases ..................................................................................................................... 37 

3.1.5 Verification of Continued Attainment. .......................................................................................... 37 

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Georgia Portion of tlte Cltattlmooga PM2.5 Nonattainment Area 

Redesignation Request and Maintenance Plan 

3.2 Contingency Provisions ..................................................................................................... 38 

3 .2.1 Contingency Measure Triggers ..................................................... : ............................................... 3 8 

3.2.2 Schedule and Procedure for Adoption and Implementation of Contingency Measures ................ 39 

3 .2.3 Contingency Measures .................................................................................................................. 40 

4.0 Motor Vehicle Emissions Budget ............................................................................... 41 

4.1 Pollntants ............................................................................................................................ 41 

4.2 Methodology ...................................................................................................................... .42 

4.3 Motor Vehicle Emissions Budgets and Safety Margins .................................................. 43 

5.0 Conclusion ................................................................................................................. 44 

6.0 References .................................................................................................................. 47 

iii 
Georgia Portion ojtlte Chattanooga PM2.5 NonattainmentArea 

Redesigmttion Request and Maintenance Plan 

LIST OF FIGURES 

Figure 1-1. PM2.5 NouattainmeutAreas iu Georgia ......................................................................... 1 

Figure 2-1. Locations of Chattanooga Nonattaiument Area PM2.5 Sampling Sites ...................... 5 

Figure 2-2. Average factor contributions to PM2.5 (1.1g/m3

) for 2002-06 at the Chattanooga STN 

site using PMF ............................................................................................................................. 9 

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

Georgia ....................................................................................................................................... 12 

Figure 2-4. S02 Emissions and Generation from North Georgia Coal-fired EGU Facilities, 

2003- 2010 .................................................................................................................................. 15 

Figure 2-5. Trend of Aggregated Annual S02 Emissions in States With Downwind 

Contributions to Georgia PM2.5 Exceeding 0.15 Jlg/m3 .......................................................... 23 

iv 
Georgia Portion of the Chattanooga PM2.5 NonattainmentArea 

Redesignation Request and Maintenance Plan 

LIST OF TABLES 

Table 1-1. PM2.5 Design Value for Chattanooga Nonattainment Area ........................................... 2 

Table 2-1. Rossville-Maple St. PM2.5 Data Collection Site .............................................................. 6 

Table 2-2. Annual and Three-year Average Ambient PM2.5 Concentrations ................................. 7 

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

Table 2-4. Annual S02 Emissions and Generation (106 MWh) from North Georgia Coal-fired 

EGU Facilities, 2003- 2010 ....................................................................................................... 14 

Table 2-5. Timetable of Federal Measure Implementation ........................................................... 18 

Table 2-6. Annual S02 Emissions in States With Downwind Contributions to Georgia PM2.5 

Exceeding 0.15 ).lg/m3 ................................................................................................................ 22 

Table 3-1. 2007 Emissions Inventory Sources ................................................................................ 26 

Table 3-2. Point Source Emissions for 2007 (tons, annual) ........................................................... 27 

Table 3-3. Nonpoint Source Emissions for 2007 (tons, annual) .................................................... 28 

Table 3-4. Largest Nonpoint PM2.5 Emissions by Source Classification ...................................... 28 

Table 3-5. Onroad Mobile Source Emissions for 2007 (tons, annual) .......................................... 29 

Table 3-6. Nonroad Mobile Source Emissions for 2007 (tons, annual) ........................................ 30 

Table 3-7. Attainment-year (2007) Emissions Inventory (tons, annual) ...................................... 30 

Table 3-8. Bases of Control and Growth Factors for 2017 and 2025 Inventories ....................... 31 

Table 3-9. Projected Point Source Emissions (tons) ...................................................................... 32 

Table 3-10. Projected Nonpoint Source Emissions (tons) .............................................................. 33 

Table 3-11. Largest Nonpoint PM2.5 Emissions by Source Classification, Year 2025 ................. 33 

Table 3-12. Projected Onroad Mobile Source Emissions (tons) ................................................... 34 

Table 3-13. Projected Nonroad Mobile Source Emissions (tons) .................................................. 35 

Table 3-14. Projected Emissions- Total of All Sectors (tons) ....................................................... 36 

Table 3-15. Emissions Decrease ....................................................................................................... 37 

Table 4-1. 2025 Motor Vehicle Emissions, Emissions Budgets, and Safety Margins .................. 43 

Table 5-1. Summary of Projected S02 Emissions- Total of All Sectors (tons) ........................... 44 

Table 5-2. Summary of Projected NO, Emissions- Total of All Sectors (tons) .......................... .45 

Table 5-3. Summary of Projected PM2•5 Emissions- Total of All Sectors (tons) ....................... .45 

v 
Georgia Portion of the Chattanooga PM2.5 Nonattainment Area 

Redesignation Request and Maintenance Plan 

LIST of APPENDICES 

Appendix A Source Apportionment ofPM2.

5 in Georgia 

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

Appendix C Emissions Inventmy Development For Two Georgia Counties in Chattanooga 

Nonattainment Area 

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

Region (Version l.IOa), Janumy 18,2012 

Appendix C-2 Area and Nonroad 2007 Base Year Inventories, Revised Final Repmt, Jan 2012 

Appendix C-3 Mobile Source Emissions Modeling for Catoosa and Walker Counties PM2.5 

Maintenance Plan Motor Vehicle Emissions Budget 

Appendix C-4 Growth and Control Factors for Aircraft, Commercial Marine Vessel, and 

Locomotive Emissions (includes memorandum from K. Thesing and two 

spreadsheets) 

Appendix C-5 Documentation of the 2012 Projection Emission Inventmy (VISTAS) 

Appendix C-6 Growth Factors, Control Factors, and Emission Summaries for Emission Inventory 

Appendix C-7 MACTEC, August 2009. Point Source, On-road, and Fire Base Year, Future Yem; 

and Control Strategy Emissions Inventories Draft Quality Assurance Project Plan 

Appendix C-8 E.H. Pechan and Associates, July 29, 2009. Quality Assurance Project Plan for Nonroad and Area Source Base Year and Future Year Emissions Inventories 

vi 
Acronym 

AEO 

AERR 

AIRS 

AQS 

CAA 

CAIR 

CARB 

CERR 

CFR 

co 

CSAPR 

DNR 

DOT 

EGAS 

EGU 

EPA 

EPD 

ERTAC 

Georgia Portion of the Clutttanooga PM2.s Nonattainment Area 

Redesignation Request and Maintenance Plan 

List of Acronyms 

Meaning Acronym Meaning 

Annual Energy Outlook FGD Flue Gas Desulfurization 

Annual Emissions Reporting FR Federal Register 

Requirements 

Aerometric Information Retrieval FRM Federal Reference Method 

System 

Air Quality Subsystem GDOT Georgia Department of 

Transp01tati on 

Clean Air Act GFC Georgia Forestty Commission 

Clean Air h1terstate Rule HC Hydrocarbon 

California Air Resources Board HPMS Highway Performance Monitoring 

System 

Consolidated Emissions Repmting ICI Industrial and 

Rule Commercial/Institt1tional 

Code of Federal Regulations MOU Memorandum of Understanding 

Carbon Monoxide MOVES Motor Vehicle Emissions Simulator 

Cross-state Air Pollution Rule MPO Metropolitan Planning Organization 

Department of Natural Resources MVEB Motor Vehicle Emissions Budget 

Department ofTranspmtation MWe Megawatt Electrical 

Economic Growth Analysis System MWh Megawatt Hours 

Electric Generating Unit NAA Nonattainment Area 

Envirolllllental Protection Agency NAAQS National Ambient Air Quality 

Standard 

Environmental Protection Division NCD NMIM County Database 

Eastern Regional Technical Advisory 

Committee 

vii 
Acronym 

NEI 

NMIM 

NTE 

NO, 

OAQPS 

PM 

PM25 

PMF 

Ppm 

RACM 

RACT 

RFP 

sec 

Georgia Portion of tile Chattanooga PM2.5 NonattainmentArea 

Redesignation Request and Maintenance Plan 

Meaning Acronym Meaning 

National Emissions Inventory SCR Selective Catalytic Reduction 

National Mobile Inventory SEMAP Southeastem Modeling Analysis Plan 

Model 

Not-To-Exceed SIP State Implementation Plan 

Nitrogen Oxides SMP Smoke Management Plan 

Office of Air Quality so2 Sulfur Dioxide 

Planning and Standards 

Particulate Matter SOA Secondary Organic Aerosols 

Fine Particulate Matter STN Speciated Trends Network 

Positive Matrix Factorization tpy tons per year 

parts per million suv Spmt Utility Vehicle 

Reasonably Available Control ULSD Ultra-Low Sulfur Diesel 

Measures 

Reasonably Available Control VISTAS Visibility Improvement State and Tribal 

Technology Association of the Southeast 

Reasonable Further Progress VMT Vehicle Miles Traveled 

Source Classification Code WRD Wildlife Resources Division 

viii 
Georgia Portion of the Chattanooga PM2.5 NonattainmentArea 

Redesignation Request and Maintenance Plan 

1.0 Introduction 

This document contains the teclmical suppmt for the Georgia Environmental Protection Division's 

(EPD's) request that the Georgia portion of the Chattanooga nonattainment area be redesignated as 

an area attaining the 1997 annual fine particulate matter (PM25) National Ambient Air Quality 

Standard (NAAQS) pursuant to Sections 107(d)(3)(D) and (E) of the Clean Air Act (CAA), as 

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

1992 (memorandum dated September 4 of that year from John Calcagni1

). 

1.1 Nonattainment Designation and Attainment Demonstration 

In 2005, EPA designated four PM25 nonattainment areas in Georgia: Chattanooga (which also 

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

their locations. The Georgia pmtion of the Chattanooga nonattainment area is located in the 

nmthwest portion of the state and consists of Catoosa and Walker counties. 

QATLA>ITA 

OcHATTANOOGA 

IIIFLOYO 

!EmMA CON 

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

1 "Procedures for Processing Requests to Redesignate Areas to Attairuuent," September 4, 1992. John 

Calcagni, Director, Air Quality Management Division, OAQPS, USEPA. 

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I 

Georgia Portion ojtlze Chattanooga PM2.

5 Nonattainment Area 

Redesign(ltion Request and Mainten(lnce P/([11 

EPA made initial designations of nonattainment areas, including the Chattanooga nonattainment area, 

for the 1997 annual PM2.s NAAQS on Janumy 5, 2005 (70FR944), and amended the designations on 

AprilS, 2005 (70FR19844). The observed PM2.

5 design value at three of the four nonattainment area 

monitors violated the annual standard, as shown in Table 1-1 below. Three of the monitors are 

located in Hamilton County, Tennessee, and one is located in Walker County, Georgia. 

Table 1-1. PM2.5 Design Value for Chattanooga Nonattainrnent Area 

Site Name 

II 

Monitor ID 

I 

PM2.5 Design Value .. 

2001-2003 (flg/m3

) . 

Siskin Drive/UTC, Tennessee 470654002 15.2 

Maxwell Road/EastRidge, 470650031 16.1 Tennessee 

Soddy-Daisy High School, 470651011 14.1 Tennessee 

Rossville- Maple St., Georgia 132950002 15.5 

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

portions of the Chattanooga nonattainment area to EPA Region 4 on October 27,2009 (cover date is 

October 16). The plan was based on modeling of the effects of existing m1d planned control 

measures on air quality in the Chattanooga area and demonstrated attainment of the standard by April 

5, 2010. 

Since EPA has detennined that the area has met the cleat1 data requirements (76FR 31239) and 

attained the standard prior to the attaimnent date (76FR 55774) (see Section 2), the SIP requirements 

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

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

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

Progress (RFP), associated RACM, and contingency requirements upon cleat1 data determination is 

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

U.S. EPA. 

1.2 Redesignation Request 

This document contains Georgia's request that the Georgia p01tion of the Chattanooga nonattairunent 

area be redesignated to attainment with respect to the annual NAAQS for PM2.5 (1997 fme 

pmticulate matter standard, retained in 2006). Section 107(d) of the CAA states that an area can be 

redesignated to attainment if the following conditions are met: 

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

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

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Georgia Portion of the Chattanooga PM2.s Nomtttainment Area 

Redesignation Request and Maintenance Plan 

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 II 0 and Patt D. 

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

as required by CAA Section 175A. 

The suppmting documentation to show that the above conditions have been met is contained in 

Sections 2 and 3. EPA's approval of this document will satisfY the fifth condition. 

1.3 Maintenance Plan 

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

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

and 

• Contingency provisions for prompt correction of any future violations. 

Per EPA guidance', the Georgia portion of the Chattanooga PM2.

5 maintenance plan also includes the 

following elements: 

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

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

• Verification of continued attainment. 

The maintenance plan is presented in Section3. 

2 "Procedures for Processing Requests to Redesignate Areas to Attairunent," September 4, 1992. John 

Calcagni, Director, Air Quality Management Division, OAQPS, USEPA. 

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Georgia Portion of the Chattanooga PM2.5 Non attainment Area 

Redesignation Request and Maintenance Plan 

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: 

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

2. The applicable implementation plan has been fully approved by EPA under Section 11 O(k). 

3. The EPA has detennined 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 tmder Section I I 0 and Part D. 

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

under CAA Section 175A. 

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

• Attainment of the annual PM25 NAAQS based on ambient data fi·om 2007 through 2009; 

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

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

reductions in emissions; and 

• The state has met all applicable requirements for the area under Section I I 0 and Pmt D. 

2.1 Attainment of the Annual PM2.s NAAQS 

A monitoring site is in attainment of the annual PM25 standard when the annual standard design 

value is less than or equal to 15.0 micrograms per cubic meter (1-1g/m3

) per Appendix N of 40 CFR 

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

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

for a single site to meet the standm·d, the annual design value calculated fi·om the previous three 

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

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

The Chattanooga area design value, based on data from 2007 through 2009, is 12.7 1-1g/m3 (Monitor 

ID 470654002), which demonstrates attainment of the standard. The monitoring network and 

ambient PM25 data are presented below. 

2.1.1 Monitoring Networ){ 

One PM25 Federal Reference Method (FRM) monitor and one PM2.

5 speciation monitor m·e located 

at the Rossville-Maple Street site (13-295-0002) in the Georgia pmtion of the Chattanooga NAA. 

The PM2.

5 FRM monitor was installed in accordance with 40 CFR 58 and has been collecting data 

since January I, 2000. Its sampling schedule was every six days until Janumy 3, 2007, when it 

slatted sampling every three days. The PM25 speciation monitor has been collecting data since 

March 23, 2005. The sampling schedule of the PM2.5 speciation monitor has been and remains every 

six days. Due to construction of the Rossville Health Depattment sampling location, these monitors 

were moved from the Rossville Health Depattment site to their current location on Maple Street. 

The samplers were temporarily shut down on June 11, 2007, and restarted on November 14, 2007. 

During this time, EPD actively searched and found a location to set up the monitoring equipment 

within the required distance to keep the smne AQS identification. 

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Georgia Portion of tile Chattanooga PM2.5 NonattainmentArea 

Redesignation Request and Maintenance Plan 

The locations of the monitoring sites are shown in Figme 2-1. PM2.

5 data collection dates at the 

Rossville-Maple Street site are presented in Table 2-1. 

• FRM (2007) 

• FRM (2002) 

+ STN (2007) 

Marion 

DeKalb 

Bledsoe 

Sequatchie 

Description of Area 

[]MPO Boundary 

~CHATTANOOGA 

Bradley 

Whitfield Murray 

Gordon 

Figure 2-1. Locations of Chattanooga N onattainment Area PM2.s Sampling Sites 

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Site Name 

I 

Georgia Portion of tile Chattanooga PM2.5 Nonattainment Area 

Redesignation Request and Maintenance Plan 

Table 2-1. Rossville-Maple St. PM2.5 Data Collection Site 

Start Date- ·~~~~~~ .. 

Start DateAQS* FRMData Speciation 

Site ID Collection Collection · Data 

Collection ·. 

Eml DateSpeciation 

Data 

Collection 

Rossville 13-295-0002 Jan. I, 2000 June 11,2007 March 23, June II, 2007 2005 

Maple Street 13-295-0002 Nov 14,2007 Nov 14,2007 

*EPA's Air Quality System 

2.1.2 Ambient PMz.s Data 

Table 2-2 shows the annual average PM2.

5 concentrations and the associated 3-year average that 

demonstrate attainment of the standard in the Chattanooga nonattainment area. The 2007-2009 

three-year design value is 12.7 ftg/m3

, which is below the standard of 15.0 f!g/m3• The table includes 

annual averages from 2003 through 2010, demonstrating the downward trend in the measured 

ambient PM2.

5 level in the nonattainment area. The 2008-20 I 0 three-year design value (Monitor ID 

4 70654002) is 11.6 ftg/m3

• This provides continued evidence that the area is meeting the standard. 

To date the quality-assured annual average for 20 II is not available. 

No data were collected from June 12-November 13,2007 at the Rossville-Maple Street site (13-

295-0002) becanse a new roof was installed in June of 2007. Because of the shutdown of the 

monitor, the Rossville site did not meet data completeness requirements for 2007. Georgia 

developed a weight-of-evidence approach for an alternative method of data substitution. The 

analysis used data from Siskin Drive (47-065-4002) and Tombras Avenue (47-065-0031) sites to 

detetmine the attainment status of the Rossville site. GA EPD's "Analysis of Rossville PM25 

Data" can be found in the EPA docket at http://www.regulations.gov (docket ID Number EPA-R04-

0AR-2011-0084-0002). The EPA Office of Air Quality Planning and Standards (OAQPS) ran a 

regression analysis in order to confirm Georgia's approach. OAQPS found that site substitution 

would be appropriate for data substitution. 

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Georgia Portion of the Chattanooga PM2.5 Nonattainment Area 

Redesignation Request and Maintenance Plan 

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

5 Concentrations 

. 

Year Monitor Monitor . . I· Monitor Monitor 

13-295-0002 4 7-065-0031 47-065-1011 47-065-4002 

(J.tg/m3) (J.tg/m3) (Jlglm3

) (J.tg/m3) . 

2003 15.9 16.5 14.3 14.9 

2004 14.9 15.6 13.3 14.5 

2005 16.4 16.1 13.8 15.5 

2006 14.4 14.3 13.1 15.0 

2007 13.7* 14.9 14.2 15.0 

2008 12.5 12.3 11.4 12.7 

2009 10.7 10.5 9.5 10.5 

2010 8.9 12.0 13.3 11.7 

2007-2009 12.3* 12.6 11.7 12.7 

2008-2010 10.7 11.6 11.4 11.6 

*Values subJect to data substttutwn (76 FR 15895) 

2.1.3 Clean Data Detennination 

On May 31, 2011, EPA promulgated its determination (76 FR 31239) that the Chattanooga 

nonattainment area had attained the 1997 atrnual average PM25 National Ambient Air Quality 

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

monitoring data for the 2007-2009 period which showed a design value of 12.7 11g/m3

• With the 

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

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

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

standard. This final rule became effective on June 30, 2011. 

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Georgia Portion oftlte Chattanooga PM2.5 Nonattainment Area 

Redesignation Request and Maintenance Plan 

2.2 Implementation Plan Under Section llO(k) 

Section II O(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 Jolm Calcagni of 

EPA states the following: 

"The SIP for the area must be fully approved under section II O(k), and must satiszy all requirements 

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

request may occur simultaneously." 

The State of Georgia has prepared and submitted a PM2.

5 attaimnent demonstration plan for the 

Georgia portion of the Chattanooga nonattainment area. The plan was submitted for approval to EPA 

Region 4 on October 27, 2009. As discussed in Section 1.1 of this redesignation request and 

maintenance plan, the attainment demonstration, RFP, associated RACM, and contingency 

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

Therefore, the attainment demonstration has been withdrawn and substituted with submittal of this 

maintenance plan. There are no longer any Section I I O(k) requirements to be met. 

2.3 Permanent and Enforceable and Other Reductions in Emissions 

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

EPA must determine) that the improvement of ambient PM25 concentrations during the years 2007 

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

that were implemented following the nonattaimnent design value period (2001 - 2003). This 

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

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

follows: 

• Source appmtiomnent, which links individual observed ambient PM25 species to specific 

e1nissions sources; 

• State control measures and associated emissions reductions; 

• Federal control measures and associated emissions reductions; and 

• Reductions ,in S02 emissions from upwind states. 

2.3.1 Source Apportionment of Ambient PM2.s 

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

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

2002-2006 speciated PM25 measurements for a standalone analysis conducted at the Hamilton 

County STN monitor (47-065-4002) (Figure 2-2). The source-apportionment results are based on 

Positive Matrix Factorization (PMF), a factor analytic method that distinguishes correlation patterns 

among speciated PM2.5 measurements in a given location. More detailed information on source 

apportionment is presented in Appendix A. 

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Georgia Portion of tire Chattanooga PM2.5 NonattainmentArea 

Redesignation Request ami Maintenance Plan 

6.27 

IIi! Mobile-sources 

IIIII Biomass-burning 

DSoil 

D Zn-rich 

IIIII Fe-rich 

IIi! Na-rich 

1111 Ca-rich 

D Sec. Sulfate 

IIIII Sec. Nitrate 

IIIIISOA 

D Unspecified 

Figure 2-2. Average factor contributions to PM2•5 (J.lg/m3

) for 2002-06 at the 

Chattanooga STN site using PMF 

These source-appmtionment results are useful for a preliminary assessment of control strategies. 

Given the large contributions to PM2.5 from the secondary-sulfate factm; it is evident that controlling 

S02 emissions (mainly from coal-buming EGUs) would reduce PM25 levels in the Chattanooga 

MSA. Controlling emissions of SOA precursors would also be usefhl. Unfortunately, these are not 

yet well understood, and limited available knowledge suggests biogenic sources as the primary SOA 

precursors. Reducing primary PM25 may be best achieved by emission reduction measures for 

mobile-source emissions and biomass burning. Contributions from all other source-categories were 

small in general. 

2.3.2 State Control Measures -Georgia 

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

associated with secondary sulfates and nitrates and biomass burning. Control of S02 is the most 

impmtant component of the strategy, as secondmy sulfates make up the largest controllable 

contribution to ambient PM25• State measures that target reduction of these emissions are: 

• S02 and NOx controls on EGUs (rule (sss)) 

• S02 limits on EGUs (rule (uuu)) 

• Smoke Management Plan 

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

by each. The con·elation between the drop in PM2.5 annual averages and the implementation of the 

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

improvements in air quality are a result of reduction in emissions and not a meteorological 

influenced phenomenon. Detailed discussions of the measures are presented in the following 

subsections. 

Table 2-3. Timetable of State Measure Implementation 

Measure Species 2001 '.02 '03 '04 I '05 '06 '07 '08 '09 I '10 

controlled . I 

PM2.5ann. 16.1 14.7 14.9 14.5 15.5 15.0 15.0 12.7 I 0.5 11.7 

avg. (~tg/m ), 

(Monitor 47-

065-4002) 

Rule (sss) SO,,NOx ~"~~ 

~~~~~ 

Smoke PM,NOx ~ ~~ Management 

Plan ~ ~~~~ wft 

Rule (uuu) so, ~ *Controls were required on December 31, 2008, but were actually slatted up in the first half of the 

year. 

2.3.2.1 S02 and NO, Controls and S02 Limits 

Atmospheric secondaty sulfate is formed from emissions of S02 . Coal-fired EGUs are by far the 

most significant source of S02 emissions in Georgia and in the Southeast. Georgia's Multipollutant 

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

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

promulgated in 2007 for the purposes of lowering ozone and PM25 concentrations by controlling 

precursor emissions and for reducing mercury deposition. The FGD controls reduced S02 emissions 

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

emissions rates by approximately 85 percent. The S02 and NOx controls were required in suppmt of 

EPA's CAIR rule, which was promulgated in 2005 and required state-wide caps for NOx and S02 

beginning in2009 and 2010, respectively. The CAIR rule is discussed fmther in Section 2.3.3. 

Georgia Rule (uuu), S02 Emissions from Electric Utility Steam Generating Units, is a companion 

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

rules were implemented in response to CAIR and require emissions reductions consistent with 

CAIR's original schedule slatting in 2009. The rule requires 95% reduction of S02 emissions from 

the majority of Georgia's coal-fired EGUs, with the requirement being phased in fi·om 20 I 0 through 

2016. 

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

affected by S02 emissions from distant sources. Even though the Georgia portion of the 

Chattanooga area has no EGU facilities, the secondary sulfate in the Chattanooga nonattainment area 

is affected by S02 emissions from coal-fired EGUs in Nmth Georgia and the Alabama pmtion of the 

Chattanooga NAA. Figure 2-3 shows the locations of the coal-fired EGU facilities in the nmthern 

half of Georgia as well as their respective energy production (in million megawatt-hours) in the year 

2007. Plant Hammond is located approximately 25 miles south of the nonattainment area. Plant 

Bowen, which is located approximately 35 miles south-southeast of the nonattaimnent area, was a 

close second to Plant Scherer in energy production and historically has been by far the highest SO,-

emitting facility in the state. Plant Wansley is located approximately 80 miles south of the 

Chattanooga nonattainment area. The facilities shown in the figure comprise seven of the ten coalfired EGU facilities that were operated in Georgia in 2007. In 2007, the energy produced by the 

seven facilities made up 97 percent of the state-wide energy production from coal-fired facilities. 

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Tennessee 

I 

million MWh 

(2007) 

0 5 10 20 

•• 

30 

N. Carolina 

S.Carolina 

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

in North Georgia 

The required FGD control implementation date varies by EGU, starting on December 31,2008. S02 

controls were actually stmted on five units in May 2008. S02 controls were operating for the entire 

year of 2009 as follows: 

• Plant Hammond - controls on 4 of 4 units; 

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

• Plant Wansley- controls on I of 2 units. 

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S02 controls on a third unit at Plant Bowen and the second unit at Plant Wansley began operation on 

April!, 2009. 

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

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

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

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

controls. 

Table 2-4 shows the annual S02 emissions for the coal-fired facilities in Nmth Georgia for the period 

2003 tln·ough 2010. The table also includes the electrical generation, a measure of production, for 

the facilities for the same time period. This data is presented in graphical form in Figure 2-4. 

For the seven facilities, S02 emissions were reduced by 60.2% and generation was down by only 

4.7%. These statistics provide clear evidence that the reduction in PM2.s concentration is due to 

permanent and enforceable controls rather than to reduced production. 

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Table 2-4. Annual S02 Emissions and Generation (106 MWh) from North Georgia 

Coal-fired EGU Facilities, 2003 - 2010 

Facility 2003 2004 2005 2006 2007 2008 2009 

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

generation 4.79 4.11 4.64 4.27 5.09 4.32 3.73 

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

generation 21.9 21.9 23.3 23.7 24.0 23.4 22.9 

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

generation 8.28 7.97 10.3 10.8 10.9 10.7 6.82 

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

generation 3.75 3.52 3.92 4.07 4.07 3.43 2.34 

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

generation 21.3 24.6 25.5 24.5 26.5 25.7 24.3 

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

generation 13.7 14 15.1 14.8 16.1 15.5 11.8 

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

generation 6.73 6.22 7.37 7.49 8.10 7.37 4.90 

TOTAL 

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

TOTAL 

Generation 106 MWh 80.45 82.32 90.13 89.6 94.76 90.42 76.79 

Ambient 

PM2.5, annual 

Monitor 47- average 

065-4002 (ng/m3

) 14.9 14.5 15.5 15.0 15.0 12.7 10.5 

... Source: EPA Clean An· Markets DivisiOn 

* S02 control, required by Georgia Rule (sss), was operational on one or more EGUs for partial or full year 

** does not include emissions fi·om facility's gas-fired units 

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2010 

. 

2,427 

3.23 

7,618 

24.7 

53,258 

6.09 

17,115 

2.28 

69,862 

24.5 

2,343 

9.8 

54,256 

6.06 

203,879 

76.65 

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Georgia Portion of the Chattanooga PM2. 5NonattainmentArea 

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700000 100 

90 600000 

80 

500000 70 

60 400000 lillllillliiiiS02 (tpy) 50 

300000 40 

--+- gen (million l'v1Wh) 

200000 30 

20 

100000 10 

0 0 C') " L() "' 1'- 00 0> 0 

0 0 0 0 0 0 0 ~ 

0 0 0 0 0 0 0 0 

"' "' "' "' "' "' "' "' 

Figure 2-4. S02 Emissions and Generation from North Georgia 

Coal-fired EGU Facilities, 2003 - 2010 

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2.3.2.2 Smoke Management Plan 

Forestry and agriculh1re, two of 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 platmed land management objectives or to mitigate catastrophic 

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

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

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

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

silvicultural, environmental, and wildlife purposes. 

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

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

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

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

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

impacts on air quality. 

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

Foreshy Commission (GFC) formulated and adopted Georgia's Basic Smoke Management Plan 

(SMP) dated April 16, 2008. The plan was developed in accordance with EPA's "The Interim Air 

Quality Policy on Wildland and Prescribed Fires" and the draft EPA guidance document, "Elements 

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

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

mitigating the impacts of air pollutants from wildland and prescribed fires on air quality and 

visibility. The plan is a necessary component in determining Exceptional Events related to 

prescribed burning and is an element of Georgia's Regional Haze SIP. The GFC, Georgia DNR's 

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

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

included as Appendix B. 

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

prescribed burns: 

• smoke mitigation, 

• smoke dispersion evaluation, 

• public notification, and 

• air quality monitoring. 

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

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

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

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

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

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

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

decisions on when to schedule prescribed burns. 

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In addition to mitigating the impacts of prescribed bums 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 detennine if attainment of the standard has been achieved. An atypical event, such as an 

unusually large forest fire, can produce PM25 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 buming is subject to enforcement through law enforcement officers of GFC, DNR and 

local law enforcement. The enforcement authority is tl1e 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 ce1tified prescribed burners if investigation reveals that 

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

of attainment in the Chattanooga area. However, implementation of the SMP will suppmt the 

maintenance of the annual PM 2.5 NAAQS. 

2.3.3 Federal Control Measures 

Federal control measures related to ambient PM25 are focused on the reduction of emissions 

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

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

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

• Tier 2 Vehicle Standards; 

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

Diesel (ULSD) Rule; 

• Large Nonroad Diesel Engines Rule and ULSD Rule; 

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

• NOx SIP Call in Surrounding States. 

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

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

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

Table 2-5 shows the timetable of implementation of these measures as well as the species controlled 

by each. The drop in PM2.5 concentration from 2005 through 2010 demonstrates that the 

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

discussions of the measures are presented in the following subsections. 

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PM2.5 ann. avg. 

(r.tg/m3

) Monitor 

47-065-4002 

Clean Air 

Interstate Rule 

(CAIR) 

Tier 2 vehicle 

standards 

Heavy Duty 

Engine Standard, 

first phase 

Large N omoad 

Diesel Rule and 

ULSD 

Table 2-5. Timetable of Federal Measure Implementation 

Species 2001 '02 '03 '04 '05 '06 '07 '08 '09 '10 

controlled . 

NO, 

NO, 

voc 

PM, NO, 

so, 

16.1 14.7 14.9 14.5 15.5 15.0 15.0 12.7 10.5 11.7 

* S02 controls required beginning 20 I 0 

2.3.3.1 Clean Air Interstate Rule 

On May 12, 2005, the U.S. EPA promulgated the "Rule To Reduce Interstate Transp01t of Fine 

Patticulate 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 NO, and sulfur dioxide (S02) and 

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

interstate transpmt of precursors to fine patticulate and ozone. 

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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 S02 in two phases, with the Phase I caps starting in 2009 and 2010, respectively. 

Phase II caps for NOx and S02 were to become effective in 2015. 

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

nonattainment areas and/or interfered with maintenance of the PM2.

5 NAAQS (70 FR 25246-25250). 

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

patt, mirrors the provisions of the federal rule. 

On July 11, 2008, the U.S. District Comt of Appeals in the District of Columbia vacated the Clean 

Air Interstate Rule and remanded it to EPA. A rehearing of the Comt'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 ofNOx and S02 from states 

identified as having significant impacts on ozone and/or PM2.

5 NAAQS attainment or as interfering 

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

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

period for the Chattanooga nonattainment area. However, before that date arrived, the D.C. Circuit 

Comt of Appeals stayed the implementation of the rule. Then, on August 21, 2012, the D.C. Circuit 

Court of Appeals issued the following order to EPA: "We vacate the Ti·amport Rule [aka CSAPR] 

and the Ti·ansport Rule F!Ps and remand this proceeding to EPA. EPA must continue administering 

CAIR pending the promulgation of a valid replacement." At this point in time, EPA has not 

announced their intended response to the comt's ruling. So, it is unknown whether or not EPA will 

appeal the decision (either to a full panel of the D.C. Circuit or the U.S. Supreme Comt), if it will 

conduct rulemaking in response to the court's decision, or take some other path forward. Regardless, 

emissions ofNOx and S02 have declined significantly and are expected to continue to decrease in the 

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

2.3.3.2 Tier 2 Vehicle Standards and Low-Sulfur Gasoline 

Federal Tier 2 vehicle standards will reduce NOx emissions fi·om 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 of0.07 grams ofNOx per mile. Implementation began 

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

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

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

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

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

the sulfur content of gasoline to 30 patts per million (ppm) slatting in Janumy of2006. Sulfur occurs 

naturally in gasoline but intetferes with the operation of catalytic convetters on vehicles resulting in 

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

standards. 

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

Rule 

New U.S. EPA standards designed to reduce NO, 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 

patiiculate matter (PM) emissions and a 95% reduction in NO, emissions for these new engines 

using low sulfur diesel, compared to older engines using diesel with higher sulfur content. S02 

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

2.3.3.4 Large Nonroad Diesel Engines Rule & Ultra Low-Suifiw 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 

NO, and PM emissions from large nonroad diesel engines by over 90%, compared to older engines 

using diesel with higher sulfur content. S02 emissions will also be reduced due to the lower fuel 

sulfur content. 

2.3.3.5 Nonroad Large Spark-Ignition Engines and Recreational Engines Standard 

This standard, effective in July 2003, regulates NO" hydrocarbons (HC) and carbon monoxide (CO) 

for groups of previously unregulated non road engines. The new standard applies to all new engines 

sold in the United States and imported after these stat1dards began and apply to large spark-ignition 

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

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

based upon the type of engine or vehicle. 

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

urban areas. Tier I of this standard was implemented in 2004 and Tier 2 statied 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 I 00%. 

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 m·e fully 

implemented, an overall 72% reduction in HC, 80% reduction in NO" and 56% reduction in CO 

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

CO, and fine PM. 

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2. 3. 3. 6 NO., SIP Call in Surrounding States 

In October 1998, the US EPA made a finding of significant contribution of NO, emissions from 

certain states and published a rule that set ozone season NO, budgets for the purpose of reducing 

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

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

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

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

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

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

2004. 

2.3.4 S02 Emissions Reductions in Upwind States 

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

affected by S02 emissions from distant sources. During the period of2003 through 2009, S02 

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

reduced. 

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

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

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

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

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

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

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

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

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

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

Table 2-6 shows the S02 emissions trends from coal-fired EGU facilities in the ten upwind states 

during the period 2003 through 2009. The total S02 emissions from the ten states dropped 

approximately 15 percent from 2003 to 2007 and over 50 percent from2003 to 2009. The trend of 

aggregated S02 emissions from these states is presented in Figure 2-5. 

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Table 2-6. Annual SO, Emissions in States With Downwind Contributions to Georgia 

PMz.s Exceeding 0.15 )tg/m3 

State 2003 2005 . 2007 2009 

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

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

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

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

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

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

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

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

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

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

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

Source: EPA Clean Air Markets Division, Acid Rain Program 

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

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

that the reduced PM2.5 levels in Georgia during the period 2007 - 2009 are due to S02 emissions 

reductions achieved both within and outside Georgia. The majority of upwind reductions result from 

state rules or consent orders requiring reduced S02 emissions. With the promulgation of the CrossState Air Pollution Rule, it is highly unlikely that these reductions will be reversed in the future. (It 

should be noted that on August 21, 2012, the D. C. Circuit Court of Appeals issued the following 

order to EPA: "We vacate the Transport Rule [aka CSAPR] and the Ti·ansport Rule FIPs and 

remand this proceeding to EPA. EPA must continue administering CAIR pending the promulgation of 

a valid replacement. " At this point in time, EPA has not announced their intended response to the 

court's ruling. So, it is unknown whether or not EPA will appeal the decision (either to a full panel 

of the D.C. Circuit or the U.S. Supreme Court), if it will conduct rulemaking in response to the 

comt's decision, or take some other path forward. Regardless, emissions of S02 from upwind states 

have declined significantly and are expected to continue to decrease in the future.) 

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7,000,000 

6,000,000 

5,000,000 

§ 4,000,000 

:!:. [fiUp;,;ind States I 

"' 3,000,000 0 

rn 

2,000,000 

1,000,000 

0 

2003 2005 2007 2009 

Figure 2-5. Trend of Aggregated Annual 802 Emissions in States With Downwind 

Contributions to Georgia PM2.5 Exceeding 0.15 )tg/m3 

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2.4 Section 110 and Part D Reqnirements 

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 

primmy ambient air quality standards. Pmt D, Subpatt 1, of CAA Title 1 (Sections 171 to 179) 

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

Section 1.1 of this maintenance plan, the Chattanooga area was designated as nonattainment for the 

1997 mmual fine PM standard in April of 2005. The area is not now and has not previously been 

designated nonattainment for any other NAAQS. 

Georgia EPD submitted a PM25 nonattainment plan for the Georgia pottion of the Chattanooga 

nonattainment area per Title I Patt D. With the determination that the Chattanooga nonattainment 

area has attained the 1997 annual fine PM standard (Section 2.1.3), the area is no longer subject to 

the nonattainment provision of CAA Section 110 m1d Pmt D requirements for demonstrating 

attainment, RFP, associated RACM, m1d contingency requirements for areas designated as 

nonattainment with the NAAQS. Therefore, the nonattainment plan was subsequently withdrawn. 

All other Section 110 and Part D requirements pertaining to the Chattanooga area have previously 

been approved or are currently subject to approval by EPA. 

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3.0 Maintenance Plan 

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

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

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

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

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

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

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

3.1 Maintenance Demonstration 

Section l75A 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 2025. 

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

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

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

Emissions projections are fmmulated for the fmal year of the maintenance period and for 

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

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

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

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

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

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

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

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

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

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

projected inventories, and verification of continued attainment. 

3.1.1 Attainment Year Emissions Inventory 

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

of the three years (2007- 2009) on which the Chattanooga area's clean data determination is based. 

The pollutants inventoried and addressed in this maintenance plan are direct PM2.

5, S02, and NO,. 

The following emissions sectors are included in the inventmy: 

• Point sources (EGU and non-EGU). 

• Nonpoint sources (including fire), 

3 "Procedures for Processing Requests to Redesignate Areas to Attainment," September 4, 1992. John 

Calcagni, Director, Air Quality Management Division, OAQPS, USEP A. 

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• Omoad mobile sources, and 

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

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

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

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

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

repmted by county and somce classification code (SCC). The SEMAP emissions inventories were 

developed using data fi'mn a number of sources, including state and local agencies and EPA's 

National Emissions Inventmy (NEI). Georgia Depmtment of Transportation developed the 2007 

inventory of on-road mobile emissions. 

The data sources for the attainment-year em1sswns inventories are summarized in Table 3-1. 

Additional details on the data somces and inventmy methods are presented in the following 

subsections and in Appendix C. 

Table 3-1. 2007 Emissions Inventory Sources 

.. 

Emissions Source Inventory Source Version I Year Basis 

Sector Generated . · . 

Point- non-EGU SEMAP Version 1.10, 2012 EPA's NEI 

Nonpoint SEMAP Revised Final EPA'sNEI 

Report, 2012 

Omoad Mobile GDOT 2012 Georgia DOT (travel demand 

model and Highway 

Performance Monitoring 

System (1-IPMS)) and 

MOVES2010a 

Nonroad Mobile SEMAP Revised Final NMIM2008, 2007 NMIM 

Report, 2012 County Database, 2008 NEI, 

ERTAC 

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3.1.1.1 Point Sources 

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

exceed I 00 tons per year of S02, NO, or patticulate matter. Emissions from point sources have been 

calculated for EGU and non-EGU sources. 

There are no EGU facilities in Catoosa or Walker counties. There is only one non-EGU point source, 

and it is in Walker County. The facility is C!ystal Springs Print Works, Inc. The 2007 emissions of 

S02, NO, and PM25 fi·om EGU and non-EGU facilities are presented in Table 3-2. 

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

Pollutant EGU Non-EGU Total Point 

so, 0 280 280 

NOx 0 48 48 

PM25 0 0 0 

The 2007 point source inventmy for the Georgia portion of the Chattanooga PM2.5 nonattainment 

area is based on the National Emissions Inventory (NEI) reports for reporting years 2005 and 2008. 

2007 emissions were estimated based on a linear interpolation between facility level 2005 and 2008 

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

Appendices C and C-1 for more details on the development of the 2007 point source emissions 

inventmy. 

3.1.1.2 Nonpoint Sources 

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

S02, NO, and particulate matter m·e each less than 100 tons per year. Emissions from nonpoint 

sources in 2007 were obtained fi·om the SEMAP final nonpoint source inventory Version 1.1. A 

default 2007 nonpoint source inventory was created that includes all of the source categories covered 

by the 2008 non point source NEI. 

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

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

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

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

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

the nonpoint inventory. 

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

rather than emission estimates. Because of the potential impot1ance of these source categories and 

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

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

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were supplemented with carry-forward categories fi·om Georgia's 2005 CERR submission grown 

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

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

The 2007 nonpoint source emissions for Catoosa and Walker counties are presented in Table 3-3. 

The largest contributor to S02 emissions was residual-oil-fired industrial boilers. The largest 

contributor to NOx emissions was industrial wood-fired boilers. The largest contributor to PM25 

emissions was road dust from unpaved roads. 

Emissions fi·om fires in 2007 were obtained from the SEMAP final "actual" fire emissions inventmy 

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

Georgia, as well as updated fuel consumption and emissions factors. 

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

Pollutant Non point Fire Total 

(excludine: fire) Nonpoint 

so, 68 9 77 

NOx 303 55 359 

PM25 1,354 195 1,548 

The 2007 level of PM2.5 emissions from nonpoint sources, excluding fire, was 1,354 tons. This 

quantity accounted for over 75 percent of total PM25 emissions in Catoosa and Walker counties. The 

top three nonpoint source classifications for PM2.5 emissions were dust from unpaved roads, 

industrial wood-fired boilers, and residential open burning of household waste (see Table 3-4). 

Table 3-4. Largest Nonpoint PM2.

5 Emissions by Source Classification 

sec Description 2007PMz.s 

(tons) 

2296000000 Unpaved Roads /All Unpaved Roads /Total: 665 

Fugitives 

2102008000 Stationmy Fuel Comb /Industrial /Wood /Total: 165 

All Boiler Types 

2610030000 Open Burning /Residential /Household Waste 140 

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3.1.1.3 Onroad Mobile Sources 

U.S. EPA's MOVES2010a mobile source emissions model was mn in rate look-up mode, and 

datasets were interpolated between 2002 and 2009 to generate 2007 on-road mobile source emissions 

of S02, NOx. and PM25 since 2007 modelmns were not available. The 2007 onroad mobile source 

emissions for Catoosa and Walker counties are presented in Table 3-5. 

Table 3-5. Onroad Mobile Source Emissions for 2007 (tons, annual) 

Pollutant · On road 

Emissions 

so, 20 

NOx 4442 

PM25 134 

Best available local data for MOVES inputs such as vehicle population, vehicle miles traveled 

(VMT) by source types, road type distribution, speed distributions, ramp fractions, hourly VMT 

fractions and age distribution were used. 

The Chattanooga Metropolitan Planning Area (MPO) travel model includes all of Catoosa County 

and the portion of Walker County within the MPO planning area. The Travel Demand Model is used 

to estimate VMT and congested flow speeds for the subregions included in the travel model. Offmodel, Highway Performance Monitoring System (HPMS) based modeling techniques were used to 

calculate emissions for the "donut" pmtion of Walker County that falls outside the MPO planning 

and travel modeling area. 

Age distribution was based on MOVES national defaults. Source type population inputs were based 

on 2002 vehicle registration data with MOVES national default vehicle type ratios. Meteorological 

information was obtained from EPA's National Mobile Inventmy Model for 2007. For a detailed 

discussion on how the on-road mobile emission inventmy was developed, see Appendix C-3. 

3.1.1.4 Nonroad Mobile Sources 

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

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

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

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

emissions sources in Catoosa and Walker counties. 2007 nonroad mobile emissions are presented in 

Table 3-6. 

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

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

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

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

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

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

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

Appendices C and C-2. 2007 Emissions from aircraft and locomotives were obtained from the 

SEMAP final nonroad mobile source emissions inventory. For more information regarding the 

SEMAP marine, aircraft, and locomotives inventory, please refer to Appendices C and C-4. 

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

Pollutant Nonroad - Aircraft Locomotive Total 

(tons) except _air and Nonroad 

rail 

so2 26 0.2 2 27 

NOx 450 1 182 633 

PM2.s 43 3 5 51 

3.1.1.5 Summmy of2007 Emissions 1nventmy 

The total 2007 Catoosa and Walker County emissions of S02, NO" and PM25 are presented for each 

source sector in Table 3-7. The majority of S02 emissions, by far, are fi·om point sources. The 

majority of NO, emissions are fi·om onroad mobile sources. The majority of PM25 emissions are 

from nonpoint sources. 

Table 3-7. Attainment-year (2007) Emissions Inventory (tons, annual) 

Pollutant Point Point. ·. Point Nonpoint Onroad Nonrmid Total 

(tons) Total EGU ... Non- Mobile Mobile . EGU . .· 

so2 280 0 280 77 20 27 404 

NOx 48 0 48 359 4,442 633 5,482 

PM2.s 0 0 0 1,548 134 51 1,733 

3.1.2 Projected Emissions Inventories 

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

2025 (the maintenance year). Emissions projections to suppmt maintenance through 2025 have been 

prepared for the years 2017 and 2025. In addition, emissions have been calculated by interpolation 

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

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

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

subsection. 

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3.1.2.1 Methods and Projected Inventories 

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

the 2007 emissions of individual sources or source categories. The control and growth factors may 

apply for some or all of the years 2008 (year following attainment inventmy) through 2025 (out· 

year). The bases used to determine these factors are summarized in Table 3-8. 

Table 3-8. Bases of Control and Growth Factors for 2017 and 2025 Inventories 

Point- non-EGU 

Nonpoint 

Nonpoint- fire 

Onroad Mobile 

Nomoad Mobile 

Nonroad Mobile 

-marine, 

aircraft, and rail 

Regulatory review - no additional 

controls defined at this time 

EGAS growth factors by SCC and county 

for 2017 and 2025. 

Regulatmy review - no additional EGAS growth factors by SCC for 2017 

controls defined at this time and 2025. 

No additional controls anticipated 

MOVES rate look-up mode (PM25, 

NO" S02) for 2025. All known 

Federal controls. 

NMIM2008 

No growth anticipated 

MOVES rate look-up mode (PM25, NO" 

S02) for 2025. Vehicle population growth 

from human population projections. 

Vehicle miles traveled (VMT) growth 

from Georgia DOT. 

NMIM2008 

SEMAP (Pechan) control factors SEMAP (Pechan) growth factors by SCC 

by sec for 2017 and 2025 for 2017 and 2025 

The pollutants whose emissions are projected are S02, NO" and direct PM2.5• As with the attainment 

inventmy, emissions from the following sectors are projected: 

• Point sources (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 C. 

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3.1.2.2 Point Sources 

There are no EGU facilities in Catoosa or Walker counties. Projected non-EGU point source 

emissions are shown in Table 3-9 (county totals). The emissions for 2017 and 2025 were estimated 

using SCC-specific and county-specific growth factors generated with EPA's Economic Growth 

Analysis System version 5.0 (EGAS 5.0). Appendix C-6 contains the SCC-specific growth factors 

for Catoosa and Walker counties. The projections show small increases in emissions for S02 and 

NOx. No additional future controls can be defined for non-EGU point sources at this time. 

Emissions levels for 2014 and 2020 were calculated by linear interpolation. 

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

Pollutant 2007 2014 2017 2020 2025 . (attainment) 

EGU 

so, 0 0 0 0 0 

NO, 0 0 0 0 0 

PM2.5 0 0 0 0 0 

Non-EGU 

so, 280 285 287 290 295 

NOx 48 49 49 50 52 

PM2.5 0 0 0 0 0 

Total Point 

so, 280 285 287 290 295 

NOx 48 49 49 50 52 

PM2.5 0 0 0 0 0 

3.1.2.3 Nonpoint Sources 

Nonpoint source emissions, excluding fire, in future years 2017 and 2025 were estimated using SCCand county-specific growth factors generated with EGAS 5.0. Appendix C-6 contains the secspecific growth factors for Catoosa and Walker counties. 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 2025 were assumed to be the same as 2007 emissions. The projections show a small 

increase in emissions of S02 as well as moderate increases in emissions of NO, and PM2.

5. 

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Table 3-10. Projected Non point Source Emissions (tons) 

Pollutant 2007 2014 2017 2020 . 

(attainment) 

Nonpoint 

(excludin~ lire) 

so, 68 72 74 75 

NOx 303 342 358 374 

PM25 1,354 1,535 1,612 1,684 

Fire 

so, 9 9 9 9 

NOx 55 55 55 55 

PM2.5 195 195 195 195 

Total Nonvoint 

so, 77 81 82 84 

NOx 359 397 414 430 

PM25 1,548 1,729 1,807 1,878 

2025 . 

78 

401 

1,804 

9 

55 

195 

87 

456 

1,998 

The top three nonpoint source classifications for 2025 PM25 emissions are dust from unpaved roads, 

industrial wood-fired boilers, and residential open buming of household waste (see Table 3-11 ). 

Projected PM2.

5 emissions from these three source classifications make up over 60 percent of total 

projected PM2.5 emissions. 

Table 3-11. Largest Nonpoint PM2.

5 Emissions by Source Classification, Year 2025 

sec Description 2025PM2.5 

(tons) 

2296000000 Unpaved Roads I AU Unpaved Roads /Total: 885 

Fugitives 

2102008000 Stationmy Fuel Comb /Industrial /Wood /Total: 223 

AU Boiler Types 

2610030000 Open Burning /Residential /Household Waste 186 

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3.1.2.4 Onroad Mobile Sources 

U.S. EPA's MOVES2010a mobile source emissions model was run in rate look-up mode to generate 

2025 onroad mobile somce emissions of S02, NOx. and PM2.5. Intermediate year emissions were 

generated by interpolating between 2007 and 2025. 

VMT and congested flow speeds were estimated by the travel demand model for areas within the 

MPO. VMT estimates derived fi·om the travel demand model were adjusted based on Federal 

Highway Administration HPMS traffic count data fi·om Georgia. Outside the MPO, VMT was 

estimated using GA HPMS traffic count data. The vehicle age distribution was based on MOVES 

national defaults. Source type population inputs were based on 2002 vehicle registration data with 

MOVES national default vehicle type ratios. Temperature and humidity inputs were assumed to be 

the same as year 2007. 

The projected onroad mobile source emissions levels are presented in Table 3-12. Onroad emissions 

of all three pollutants trend downward during the maintenance period. The trend in S02 is of less 

importance since onroad mobile sources emit very little S02• For a detailed discussion on how the 

onroad mobile emission inventmy was developed, see Appendix C-3. 

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

Pollutant 2007 2014 2017 2020 2025 

(tons) (attainment) 

so, 20 17 15 14 II 

NOx 4,442 3,112 2,542 1,972 1,022 

PM2.5 134 96 80 63 36 

3.1.2.5 Nonroad Mobile Sources 

Projections of nonroad emissions in 2017 and 2025, excluding air and rail sources, were calculated 

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

used for other inputs. 

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

operation (ITO) projections available from the Federal Aviation Administration's Tenninal Area 

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

control factors were applied to aircraft emissions. 

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

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

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

EPA's locomotive engine regulatmy impact analysis and associated emission factor guidance. 

The non road mobile source emissions projections are presented in Table 3-13. Total emissions of all 

three pollutants trend downward during the maintenance period. As with omoad sources, the 

downward trend in S02 is of less impmtance since nonroad sources emit ve1y little S02. For a 

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

C. 

Table 3-13. Projected Nonroad Mobile Source Emissions (tons) 

Pollutant 2007 2014 2017 2020 2025 

(tons) (attainment) 

Non road* 

so, 26 8 0.6 0.6 0.6 

NO, 450 296 230 204 160 

PM25 43 31 26 23 17 

Aircraft 

so, 0.2 0.2 0.2 0.2 0.2 

NOx 1 1 1 I I 

PM25 3 3 3 3 3 

Locomotive 

so, 1.6 0.5 0.1 0.1 0.1 

NOx 182 153 141 132 116 

PM,.s 5 4 3 3 2 

Tot. Nonroad 

so, 27 8.8 0.8 0.8 0.9 

NO, 633 450 372 336 277 

PM,.s 51 38 32 28 22 

* excludmg mrcraft and locomotive emiSSions 

3.1.3 Emissions Projections Summary and Demonstration of Maintenance of Attainment 

The consolidated emissions projections for all Catoosa and Walker County sources are presented in 

Table 3-14. Emissions of S02 and NOx drop from 2007 to 2025. This is a reflection of the 

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

period. Overall, emissions of S02 and NOx are projected to decline by 2.5 percent and 67 percent, 

respectively, over the course of the maintenance period. 

Emissions of PM25 rise from 2007 through 2025. This is a reflection of an increase in nonpoint 

source emissions (primarily road dust and industrial wood boilers) which is pmtially offset by 

reductions in the omoad and nonroad sectors. The overall rise in PM25 is 18.6 percent of attainment 

year emissions. Therefore, fmther evaluation is needed to judge whether the increase ·in PM25 

emissions, in combination with the decreases in S02 and NOx emissions, is likely to provide for 

maintenance of the standard. 

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Table 3-14. Projected Emissions- Total of All Sectors (tons) 

Pollutant 2007 2014 2017 2020 2025 % change, 

(tons) (attainment) 2007-2025 

so, 404 391 385 389 394 -2.5 

NOx 5,482 4,009 3,377 2,788 1,806 -67.1 

PM25 1,733 1,863 1,918 1,970 2,056 +18.6 

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

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

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

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

quality impact for each. 

For this purpose, Georgia EPD examined speciation data available from the EPA Air Explorer Web 

site for 2007- 2009 for the Chattanooga monitor (site 47-065-4002). The 3-year average of this data 

suggests that ambient PM25 in Chattanooga consists of approximately 48.1 percent sulfate, 2.4 

percent nitrate, 40.6 percent organic particulate (which consists of directly-emitted primary organic 

matter and atmospherically fanned secondmy organic aerosol), 5.0 percent misceJlaneous inorganic 

particulate (sometimes labeled "crustal particles"), and 3.9 percent other types of particulate matter. 

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

matter, direct PM2_5 species make up 45.6 percent (sum of 40.6 and 5.0) of the total ambient PM25. 

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

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

with changes in total nonattainment area emissions of direct PM25. This analysis thus assumes that 

the direct PM25 component of ambient PM2_5 will increase by the 18.6 percent projected increase in 

direct PM25 emissions. This approach was used by U.S. EPA in its evaluation and approval of the 

annual PM25 redesignation request for the Evansville, Indiana, nonattainment area (see 76 FR 29695 

and 76 FR 59527). 

In the Chattanooga analysis, the baseline concentration is conservatively assumed to be 15.0 f1g/m3

• 

Direct PM2_5 is estimated to contribute 45.6 percent, or 6.84 ftg/m3

, of the 15.0 ftg/m3. Georgia 

EPD's assessment assumes that the projected increase in direct PM2_5 emissions will cause a 

corresponding 18.6 percent increase in ambient concentrations of PM2.5, which would suggest an 

increase in the ambient concentration of the direct PM2_5 component by 1.27 f1g/m3

• 

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

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

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

the Eastern United States. Modeling conducted by EPA for the Cross State Air Pollution Rule 

(CSAPR) estimated that future Chattanooga concentrations with the final CSAPR in place would be 

3.7 f1g/m3 below the standard (2014 Remedy Average case*). In addition, the emissions reductions 

that have already occurred have brought measured Chattanooga concentrations to 11.6 ftg/m3 (as 

shown in Table 2-2). Therefore, the 1.27 f1g/m3 increase in the components associated with direct 

PM2_5 would not be expected to yield concentrations above the standard. That is, GA EPD believes 

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that maintenance of the annual PM2.5 standard is demonstrated despite the small projected increase in 

direct PM2.5 emissions. 

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

3.1.4 Emissions Decreases 

An emissions smplus represents the degree of improvement (reduction) in 2025 emissions compared 

to the attainment year (2007) emissions. The surpluses are shown in Table 3-15 for each pollutant. 

A positive surplus reflects an emissions decrease from the attainment year to 2025. The negative 

surplus for PM2.5 reflects a projected increase in emissions. A portion of the NO, surplus will be 

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

Table 3-15. Emissions Decrease 

Pollutant Surplus . 

Emissions* . 

2007 to2025 (tons) 

so, 10 

NOx ** 3,676 

PMz.s ** -323 

* Surplus= (2007 emissions level)- (2025 emissions level) 

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

3.1.5 Verification of Continued Attainment 

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

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

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

emissions inventory. 

The location and operation of EPD's FRM monitor in Georgia's portion of the Chattanooga area are 

described in Section 2.1 of this plan. During the maintenance period EPD will continue to operate a 

federal reference monitor in Walker County per the requirements of 40 CFR Part 58. 

The Consolidated Emissions Repmting Rule (CERR) was promulgated by EPA on June I 0, 2002. 

The CERR was replaced by the Annual Emissions Repmting 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 

pmtion, and the omoad and nonroad mobile sources continue to be quantified on a tlu·ee-year cycle. 

The inventory will be updated and maintained on a tlu·ee-year cycle. As required by the AERR, the 

next overall emissions inventory will be compiled for 20 II. 

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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 occm~ after redesignation of an area as an attainment area. The measures may include 

rules or other measures that are not yet effective, but EPD agrees to adopt and implement, as 

expeditiously as practicable, when required by this plan. The minimum requirement for contingency 

provisions is the implementation of all measures that were contained in the SIP for the area (i.e., the 

nonattainment plan) before the redesignation. In addition, EPA guidance (John Calcagni memo 

dated September 4, 1992) specifies the following pertaining to contingency provisions in the 

maintenance plan: 

• identification of additional measures that would be considered for implementation 

should a violation occur; 

• identification of triggers for the implementation of additional contingency measures; and 

• a schedule and procedure for adoption and implementation of additional measures (with 

time limit). 

3.2.1 Contingency Measure Triggers 

Section 175A(d) of the Clean Air Act Amendments requires that the maintenance plan include 

provisions for contingency measures that would promptly be implemented by the state to correct any 

violation of the annual PM25 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 Georgia pmiion of the Chattanooga PM2.5 

maintenance area. Contingency measures are intended to provide further emission reductions in the 

event that violations of the NAAQS occur after redesignation to attainment. Consistent with this 

plan, EPD agrees to adopt and implement, as expeditiously as practicable, the necessmy con·ective 

actions in the event that violations of the standard occur within the maintenance area after 

redesignation to attainment. Contingency measures as described below would be adopted and 

implemented within 24 months of a contingency trigger unless EPD has demonstrated that technical 

or economic feasibility warrm1ted 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. ln accordance with 40 CFR Pmi 58, ambient 

monitoring data that indicates a violation of the annual PM25 NAAQS will begin the process to 

implement these contingency measures according to the protocols identified below. The contingency 

plan provides for corrective responses should the NAAQS be violated, or if emissions in the Georgia 

pmtion of the Chattanooga maintenance area increase significantly above current levels. 

Tier I. A Tier 1 trigger is activated when any one of the following conditions occurs: 

• the previous calendar year's annual average PM25 concentration exceeds the standard by 

1.5 ug/m3 or more; 

• the mmual average PM25 concentration in each of the previous two consecutive calendar 

years exceeds the standard by 0.5 ug/m3 or more; 

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• the total maintenance area S02 emrssrons in the most recent NEI exceeds the 

corresponding attainment-year inventmy by more than 30.0 percent; and 

• the total maintenance area PM2.s emissions in the most recent NEI exceeds the 

corresponding attainment-year inventory by more than 30.0 percent. 

EPD will conduct an evaluation as expeditiously as practicable to determine if the trend is likely to 

continue. If it is determined that additional emission reductions are necessary, EPD will adopt and 

implement any required measures in accordance with section 3.2.2. 

The PM2.5 trigger concentrations described above apply to the PM2.

5 federal reference monitors in the 

maintenance area. EPD will evaluate a Tier I condition, if it occurs, as expeditiously as practicable 

to determine the cause(s) of the ambient PM2.

5 or emissions inventory increase and to determine if a 

Tier II condition (see below) is likely to occur. 

Tier II. A Tier II trigger is activated when any violation of the annual PM2.s NAAQS at any FRM 

ambient monitoring station in the Chattanooga maintenance area is recorded, based on qualityassured monitoring data. In this event, EPD will conduct a comprehensive study to determine the 

cause(s) of the ambient PM,.s 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 I) a Tier II trigger condition or 2) a Tier I condition in which EPD has 

determined that a Tier II condition is likely to occur, conduct a comprehensive study to determine 

whether or not contingency measures are required for the maintenance of the PM2.s standard. Since 

Catoosa and Walker counties may be influenced by emissions from outside the maintenance area, the 

study will attempt to detennine whether the trigger condition is due to local emissions, emissions 

from elsewhere, or a combination of the previous. The comprehensive analysis, based on qualityassured 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 transpmi; 

• the geographic applicability of possible contingency measures; 

• emission trends, including implementation timelines of potential control measures; 

• time lines of "on-the-books" (adopted) measures that are not yet fully implemented [e.g., 

Georgia Rule (sss) and Rule (mm) S02 controls]; and 

• current and recently identified control teclmologies. 

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

no later than nine months after the Tier I or Tier II trigger is activated. If EPD determines, through 

the comprehensive study, that contingency measures are required for maintenance of the standard, 

the appropriate corrective measures wi11 be adopted and implemented within 18 to 24 months after 

the Tier I or II trigger occurs. These control measures which will continue to produce substantial 

reductions in fine particulate matter and its precursors in excess of what is relied upon in this 

maintenance plan, include the Georgia Multipollutant Rule, which is described in section 2.3.2.1 of 

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this maintenance plan, as well as diesel engine retrofit, replacement, and repowering programs and 

truck stop electrification programs which are currently being implemented by Georgia EPD. 

If the study determines that additional measures are required, rules will be adopted no later than 18 

months following the date on which the Tier I or Tier II trigger is activated. Selection of measures 

will take into consideration the ease of implementation as well as technical and economic feasibility. 

If it is determined that adoption and implementation of a rule will take longer than 24 months 

following the trigger date, EPD will submit for EPA's approval a revised schedule for the 

development and adoption of contingency measures. 

3.2.3 Contingency Measures 

If the analysis required above determines emissions from the local area are contributing to the trigger 

condition, EPD will evaluate those measures as specified in Section 172 of the CAA for control 

options as well as other available measures. If a new measure/control is already promulgated and 

scheduled to be implemented at the federal or state level, and that measure/control is determined to 

be adequate, additional local controls may be unnecessary. Under Section 175A(d), the minimum 

requirement for contingency measures is the implementation of all measures that were contained in 

the SIP before the redesignation. Currently all such measures are in effect for the Chattanooga NAA; 

however, an evaluation of those measures, such as RACT, can be performed to determine if 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 ofS02 and PM2.

5; 

• Reasonably Available Control Technology (RACT) for point sources of S02 and PM2.5 ; 

• Expansion ofRACM/RACT to area(s) of transport within the State; 

• Mobile source measures; and 

• Additional S02 and/or PM25 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 necessmy 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 patticipation. This process will include issuance of notices, 

m1 opportunity for public hearing, and other measures required by Georgia law. 

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4.0 Motor Vehicle Emissions Budget 

The transpmtation confonnity rule (40CFR93.100 - 40CFR93.129) ensures that projects and plans 

funded by the Federal Highway Administration and the Federal Transit Administration conform to air 

quality SIPs and maintenance plans. h1 the case of a NAAQS maintenance plan, the rule requires a 

motor vehicle emissions budget (MVEB) to be established for the last year of the plan's maintenance 

period. The rule, at 40CFR93.124(a), describes a motor vehicle emissions budget as " ... the 

implementation plan's estimate of future [motor vehicle J emissions." Such budgets establish caps on 

motor vehicle emissions; projected emissions from transpmtation plans and programs must be equal 

to or less than these caps for a positive conformity dete1mination to be made. Transpmtation 

conformity determinations are required for non-exempt, federally-funded highway and transit 

projects before they are funded and approved and for transpottation plans and transportation 

improvement programs. The budget presented in this section applies to the Georgia pmtion of the 

Chattanooga NAA only. 

4.1 Pollutants 

For Catoosa and Walker counties, MVEBs will be set for direct PM2.s and NOx only. 40 CFR Patts 

93 .119(f)(7) through (1 0) identifY the PM2.5 pollutants which must be analyzed for transpmtation 

conformity purposes. These patts of the rule are listed below: 

§119(j)(7)- PM2.

5 in PM25 areas; 

§ 11 9(j)(8) - Reentrained road dust in P M2.5 areas only if the EPA [Environmental Protection Agency} 

Regional Administrator or the director of the State air agency has made a finding that emissions 

from reentrained road dust ·within the area are a significant contributor to the PM2.s nonattainment 

problem and has so notified the MPO and DOT [Department of Transportation}; 

§119(j)(9)- NO, [nitrogen oxides] in PM25 areas, unless the EPA Regional Administrator and the 

director of the State air agency have made a finding that emissions ofNO,fi'O/n within the area are 

not a significant contributor to the PM25 nonattainment problem and has so notified the MPO and 

DOT; and 

§119(j)(10)- VOC, S02 and/or ammonia in PM2.5 areas if the EPA Regional Administrator or the 

director of the State air agency has made a finding that any of such precursor emissionsfi'om within 

the area are a significant contributor to the PM25 nonattainment problem and has so notified the 

MPOandDOT 

Primaty, or direct, PM2.5 emissions must be considered for all transportation conformity regional 

emissions analyses. For Chattanooga, NOx must also be considered since EPA has not approved 

Georgia EPD's finding that NOx is not a significant contributor to the PM25 nonattainment problem 

in Chattanooga. None of the other pollutants identified (reentrained road dust, VOC, and ammonia) 

above have been determined by EPA or Georgia EPD to be significant contributors to PM 

nonattainment in Chattanooga. S02 from coal combustion is significant but levels of S02 emissions 

from mobile sources m·e vmy low and, therefore, not significant for transpmtation conformity 

purposes. 

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4.2 Methodology 

In preparation of this Chattanooga PM2.5 Maintenance Plan, EPD worked closely with the Georgia 

Department of Transpottation (GDOT) and the Chattanooga-Hamilton County-Nmth Georgia 

Transpmtation Planning Organization (TPO) to develop the estimates of mobile source emissions for 

the Georgia portion of the Chattanooga nonattainment area. The Chattanooga-Hamilton CountyNmth Georgia Transpmtation Planning Organization is the metropolitan planning organization 

(MPO) for the Chattanooga urbanized area. Mobile source inventories for 2025 were developed 

using the latest available planning assumptions, the most recent travel demand model, EPA's latest 

motor vehicle emission factor model, and, in the case of Georgia counties in the MPO, 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 

2025 MVEBs are based is discussed below. 

Emissions fi·om 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) were 

determined from a county-specific travel demand model and/or HPMS traffic count data. Vehicle 

emissions factors were determined from a motor vehicle emissions model. See Appendix C-3 for 

more details on the development of the travel demand model and the determination of emissions 

factors. 

The MOVES201 Oa motor vehicle emission model was used to calculate 2025 emission factors with 

all currently known 2025 mobile source control rules in place. The MOVES model was run in rate 

look-up mode. The emission factors reflect all federal controls, e.g., the Federal Motor Vehicle 

Control Program including Tier 1 and (beginning with 2006 models) Tier 2 tailpipe standards; and 

the National Low Emission Vehicle program. MOVES20 I Oa produces three sets of emission factors 

per run: 

• rate per distance; 

• rate per vehicle; and 

• rate per profile. 

Of these three types of emission factors, the first is multiplied by VMT and the second two by 

vehicle population. Note that rate-per-profile emissions (i.e., vapor venting) are not applicable to 

PM2.

5 modeling. 

The Chattanooga TPO travel demand model is developed and maintained by Cambridge Systematics, 

Inc., and model output for the Georgia portion of the MPO is managed 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 transpmtation conformity 

calculations is consistent with the transportation conformity rule at 40CFR93.122(b) and (d), which 

requires a network-based travel model emissions estimation methodology if the use of such 

procedures has been the previous practice of the MPO. The use of such a methodology has been the 

previous practice of the Chattanooga TPO. Off-model techniques based on HPMS data were used to 

calculate emissions for the portion of Walker County that falls outside the Chattanooga MPO area 

but is still inside the non-attainment area (referred to as a "donut" area). 

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Section 93.1 05(b) of the Transpmtation Conformity Rule and Sections I 06(g) and I 06(h) of 

Georgia's transpmtation conformity SIP require interagency consultation for SIP development. 

Accordingly, a detailed listing of the procedures and planning assumptions used for the regional 

emissions analysis suppmting development of the MVEB was presented to the Chattanooga 

interagency consultation committee for review in November of 2011. The assumptions used to 

develop Chattanooga's conforming Long Range Transpmtation Plan and Transpmtation 

Improvement Program were also used to develop the network and emissions for this maintenance 

planMVEB. 

4.3 Motor Vehicle Emissions Budgets and Safety Margins 

The projected 2025 on-road motor vehicle emissions for direct PM2_, and NO, are 36 and I ,022 tons, 

respectively. A budget for S02 is not required. On-road emissions of S02 are considered to be "deminimis" (70FR 24283), and, therefore, no budget is necessaty. The on-road mobile emissions, 

emissions budgets, and safety margins are preseuted in Table 4-1. A safety margin is necessaty to 

accommodate the variabilities or worst-case scenarios that can occur due to future planning 

assumptions. 

The worst-case daily motor vehicle emtsstons projection for PM2_5 is 22.8 percent above the 

projected 2025 on-road emissions. In a worst-case scenario, the needed annual safety margin for the 

MVEB would be 8.2 tons resulting in an overall MVEB of 44.2 tons per year. 

The worst-case daily motor vehicle emissions projection for NOx is 35.7 percent above the projected 

2025 on-road emissions. In a worst-case scenario, the needed annual safety margin for the MVEB 

would be 364.6 tons resulting in an overall MVEB of 1,386.5 tons per year. 

Table 4-1. 2025 Motor Vehicle Emissions, Emissions Budgets, and Safety Margins 

Pollutant Projected 2025 Safety Margin Safety Margin MVEB* with Safety 

On-Road Allottee! to MVEB Allotted to Margin (tons) 

Emissions (%) MVEB(tons) 

(tons) 

PM25 36.0 22.8 8.2 44.2 

NO, 1,021.8 35.7 364.6 1,386.5 

*MVEB for the Georgia pmtion of the Chattanooga NAA. 

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5.0 Conclusion 

Section 107(d) of the CAA states that an area can be redesignated to attainment if the following 

conditions are met: 

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

2. The applicable implementation plan has been fully approved by EPA under Section II O(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 S02 Emissions -Total of All Sectors (tons) 

2007 

attainment 2014 2017 2020 2025 

Source 

(tons) (tons) (tons) (tons) (tons) 

Point - total 280 285 287 290 295 

Area- total 77 81 82 84 87 

Non-road- total 27 8.8 0.8 0.8 0.9 

On road 20 17 15 14 II 

Total 404 391 385 389 394 

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Table 5-2. Summary of Projected NO, Emissions- Total of All Sectors (tons) 

. 

2007 

attainment 2014 2017 2020 2025 

Source (tons) (tons) (tons) (tons) (tons) . 

Point - total 48 49 49 50 52 

Non point- total 359 397 414 430 456 

Non-road -total 633 450 372 336 277 

Onroad 4,442 3,112 2,542 1,972 1,022 

Onroad Safety 364.6 

Margin 

Total 5,482 4,009 3,377 2,788 2,171 

Table 5-3. Summary of Projected PM2.

5 Emissions -Total of All Sectors (tons) 

2007 

attainment 

2014 2017 2020 2025 

Source (tons) (tons) (tons) (tons) (tons) 

. 

Point- total 0 0 0 0 0 

Nonpoint- total 1,548 1,729 1,807 1,878 1,998 

Non-road- total 51 38 32 28 22 

Onroad 134 96 80 63 36 

Onroad Safety 8.2 

Margin 

Total 1,733 1,863 1,918 1,970 2,064 

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The supporting documentation to show that the above conditions have been met for the Georgia 

portion of the Chattanooga nonattainment area is contained in this document. Based on the 2007-

2009 monitored design value for the Chattanooga nonattainment area, EPA has published in the 

Federal Register its final rule that the nonattainment area has attained the 1997 annual average PM25 

National Ambient Air Quality Standard (NAAQS). The maintenance demonstration in this document 

shows that, based on comparison of projected emissions to attainment year emissions, emissions are 

expected to stay at or below levels commensurate with attaining air quality through the year 2025 as 

illustrated by Tables 5-l, 5-2 and 5-3 above. Analysis was presented to demonstrate that the standard 

will be maintained despite a projected increase in direct PM25 emissions. This document also 

contains provisions for contingency measures should emissions levels or ambient concentrations rise 

unexpectedly. EPA's concurrence that the improvement in Chattanooga's air quality is due to 

permanent m1d enforceable reductions in emissions and EPA's approval of this document will satisfy 

Items 3 and 5 above. Therefore, Georgia EPD requests that the Georgia pmtion of the Chattanooga 

nonattainment area, Catoosa and Walker counties, be redesignated from nonattaimnent to attainment 

with respect to the !997 ammal NAAQS for fine particulate matter. In addition, 2025 MVEBs have 

been presented for omoad mobile emissions of direct PM25 and NOx. These emissions budgets are 

required by EPA's transportation conformity rule as tools for ensuring conformance of highway and 

transit plans with air quality SIPs and maintenance plans. 

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6.0 References 

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

US Energy Information Administration, Annual Energy Outlook 20 I 0, April 20 I 0. 

US EPA, Air Quality Modeling Final [Cross-state Air Pollution] Rule Technical Supp01t Document, 

June 2011, Docket lD No. EPA-HQ-OAR-2009-0491-4140. 

USEPA, "Approval, and Promulgation of Air Quality Implementation Plans; Indiana; Redesignation 

of the Evansville Area to Attainment of the Fine Particulate Matter Standard"; proposed rule, 76 FR 

29695. 

USEPA, "Clean Data Policy for the Fine Patticle National Ambient Air Quality Standards," 

Memorandum from Stephen Page, December 14, 2004. 

USEPA, "Determination of Attaining Data for the 1997 A1111ual Fine Pmticulate Standard; Alabama, 

Georgia, and Tennessee: Chattanooga, Final Rule"; 76 FR 31239- 31241. 

USEPA, "Federal Implementation Plans: Interstate Transport of Fine Particulate Matter and Ozone 

and Correction of SIP Approvals" [a.k.a. "Cross-State Air Pollution Rule"]; final rule, 76 FR 48208. 

USEPA, National Emissions Inventory: inventory years 2005, 2007, and 2008. 

USEPA, "Procedures for Processing Requests to Redesignate Areas to Attainment," Memorandum 

from John Calcagni, September 4, 1992. 

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Georgia's Redesignation Request and 

Maintenance Plan for the Chattanooga 

NonattainmentArea for the 1997 PM2.s NAAQS 

For Catoosa and Walker Counties 

August 31, 2012 

Prepared by: 

Georgia Department of Natural Resources 

Environmental Protection Division 

Air Protection Branch