# Proposed Georgia's 15% Reasonable Further Progress State Implementation Plan Revision for the Atlanta 8-Hour Ozone Nonattainment Area

March 26, 2009

Prepared By:



## Georgia Department of Natural Resources Environmental Protection Division Air Protection BranchThis page was intentionally left blank.

## TABLE OF CONTENTS

EXECUTIVE SUMMARY .......................................................................................................... 1

1.0 INTRODUCTION............................................................................................................. 3

2.0 PLAN REQUIREMENTS................................................................................................ 5

3.0 8-HOUR OZONE 15% REASONABLE FURTHER PROGRESS PLAN ................. 6

3.1 I NTRODUCTION ................................................................................................................ 6 3.2 C ALCULATION OF E MISSION T ARGET L EVELS ................................................................. 6
3.2.1 Procedure for Development of Target Levels......................................................... 6
3.2.2 2002 Reasonable-Further-Progress Base Year Inventories................................... 7
3.2.3 Adjusted Base Year Inventories .............................................................................. 8
3.2.4 Required Emissions Reductions............................................................................ 10
3.2.5 Target Levels of Emissions ................................................................................... 10

4.0 CONTROL MEASURES ............................................................................................... 12

4.1 P OINT S OURCE C ONTROL M EASURES ............................................................................ 12
4.2 A REA S OURCE C ONTROL M EASURES ............................................................................. 13
4.3 N ONROAD M OBILE S OURCE C ONTROL M EASURES ........................................................ 13
4.4 M OBILE S OURCE C ONTROL M EASURES ......................................................................... 13

5.0 PROJECTED EMISSIONS ........................................................................................... 14

5.1 E MISSIONS P ROJECTION O VERVIEW ............................................................................... 14
5.2 P ROJECTED 7-C OUNTY 2008 VOC E MISSIONS S UMMARY ............................................. 15
5.3 P ROJECTED 13-C OUNTY 2008 NO X E MISSIONS S UMMARY ........................................... 16
5.4 E MISSIONS P ROJECTION M ETHODOLOGY BY S OURCE C ATEGORY ................................. 17
5.4.1 Point Source Emissions Projections ..................................................................... 17
5.4.2 Area Source Emissions Projections...................................................................... 17
5.4.3 Nonroad Mobile Source Emissions Projections ................................................... 17
5.4.4 Mobile Source Emissions...................................................................................... 18

6.0 MOTOR VEHICLE EMISSIONS BUDGETS ............................................................ 19

6.1 B ACKGROUND ................................................................................................................ 19
6.2 E STABLISHMENT OF 2008 M OTOR V EHICLE E MISSIONS B UDGETS FOR THE A TLANTA 8-

HOUR O ZONE N ONATTAINMENT A REA ...................................................................................... 19

7.0 IMPLEMENTATION SCHEDULE ............................................................................. 22

8.0 MILESTONE FAILURE CONTINGENCIES ............................................................ 23

9.0 REPORTING REQUIREMENTS ................................................................................ 24

10.0 CONCLUSIONS ............................................................................................................. 25

iLIST OF TABLES

Table 1 -- 13-County 2002 Reasonable-Further-P rogress Base Year NOx Inventory ................... 8 Table 2 -- 7-County 2002 Reasonable-Further-P rogress Base Year VOC Inventory .................... 8 Table 3 -- 13-County FMVCP/RVP Reductions ............................................................................ 9 Table 4 -- 7-County FMVC P/RVP VOC Reductions..................................................................... 9 Table 5 -- 2002 Adjusted to 2008 Base Year 13-County NOx Inventory ...................................... 9 Table 6 -- 2002 Adjusted to 2008 Ba se Year 7-County VOC Inventory...................................... 10 Table 7 -- Required 13-Count y NOx Reductions for 2008........................................................... 10 Table 8 -- Required 7-Count y VOC Reductions for 2008............................................................ 10 Table 9 -- NOx Emissions Target Level for 2008, 13-County Area ............................................ 10 Table 10 -- VOC Emissions Target Level for 2008, 7-County Area............................................ 11 Table 11 -- 2008 7-County Pr ojected VOC Emissions................................................................. 15 Table 12 -- 2008 13-County Av ailable VOC Reductions............................................................. 16 Table 13 -- 2008 Projected 13-County NOx Emissions ............................................................... 16 Table 14 -- 2008 7-County Ava ilable NOx Reductions ............................................................... 16 Table 15 -- 2008 20-County Atlanta Nonatta inment Area Projected Emissions.......................... 19 Table 16 -- Total 20-County 2008 Moto r Vehicle Emissions Budgets ........................................ 21 Table 17 -- VOC Target Level and Projec ted Emissions for the 15% RFP Plan ......................... 25 Table 18 -- NOx Target Level and Project ed Emissions for the 15% RFP Plan.......................... 25

LIST OF APPENDICES

Appendix A, Sensitivity of ozone concentrations in Atlanta to NOx and VOC controls
inside and outside the nonattainment area Appendix B, EPA Approval of Ge orgia Gasoline Control Program Appendix C, Mobile Source Emissions Modeling for Atlanta 15% RFP Plan Appendix D, Controls on Large Electric Utility Steam Generating Units Appendix E, Documentation of VISTAS I nventories and Georgia 2002 CERR Inventory Appendix F, Effect Of Senior Exempti on on 2002 Highway Mobile Source Emissions

iiEXECUTIVE SUMMARY

Section 182 of the federal Clean Air Act Amendments of 1990 (CAA) requires ozone nonattainment areas with air quali ty classified as "moderate" or worse to submit plans showing reasonable further progress towards attainment of the national ambient air quality standards (NAAQS).

On April 30, 2004, EPA designated 20 metropol itan Atlanta counties as a "marginal"
nonattainment area under the 8-hour ozone stan dard. The 8-hour ozone nonattainment area encompasses the 13 counties of the former 1-hour ozone nonattainment area 1 plus seven additional "ring" counties: Ba rrow, Bartow, Carroll, Hall, Newton, Spalding, and Walton. With an attainment deadline of June 15, 2007, marginal 8-hour ozone areas were re quired to attain the NAAQS by the 2006 ozone season. Because mo nitoring data from the 2006 ozone season indicated that Atlanta had not attained the NAAQS, the area was reclassified to "moderate." In ozone nonattainment areas with air quality classi fied as "moderate" or worse, the reasonable further progress (RFP) requirement established in Section 182(b) of the CAA prescribes emission reductions from the baseline totaling 15% within six years of the base year (i.e., by the end of 2008 for the 8-hour ozone NAAQS).

This 15% Reasonable Further Progress Plan is not required or intended to demonstrate attainment of the ozone NAAQS; it is a desc ription of how the 15% additional emission reductions required in the Atlanta area by 2008 were achieved. This 15% RFP Plan establishes 2008 motor vehicle emissions budgets of 171.83 and 272.67 tons per day, VOC and NOx, respectively, for the 20-county Atlanta 8-hour oz one nonattainment area. Note that the motor vehicle emissions budgets are essentially the 2008 mobile 2 source emission inventories for the
Atlanta nonattainment area and do not include emi ssions from outside the nonattainment area. In order to complete the 15% RFP Plan in acco rdance with EPA guidance, 2002 VOC and NOx emissions inventories for the 20-county nonattainment area were produced. The 2002 inventories were adjusted by removing VOC and NOx already scheduled for control by previous federal regulations on motor vehicles and ga soline volatility. The required VOC and NOx reductions (15%) and the resulting target leve ls of future VOC and NOx emissions were calculated, and growth in emissions was projected. Projecte d emissions of VOC and NOx reflect control rules already adopted and implemented. In the nonattainment area as a whole, these
controls were found to be more than suffici ent to reduce overall emissions by the required amounts and also to offset all of the growth in emissions projected to occur between 2002 and 2008. Although projected emissions for 2008 are above the target levels ca lculated for 7-county VOC and 13-county NOx (see tables below), with VOC reductions from the 13-county area and NOx reductions from the 7-county area the 15% em issions reductions required in the Atlanta area by 2008 are easily achieved.

1 Cherokee, Clayton, Cobb, Coweta, DeKalb, Douglas, Fayette, Forsyth, Fulton, Gwinnett, Henry, Paulding, and
Rockdale.

2 The term "mobile" is used to describe emissions from on-road motor vehicles. The term "nonroad" is used to describe emissions from off-road equipment and vehicles.

1VOC Target Level and Projected Emissions for the 15% RFP Plan

2008 VOC Emissions (tons/day) 7-County VOC

Target Level Projected 7-County VOC Inventory Tons over 7- County Target Available 13-County VOC Reductions Excess Nonattainment Area VOC Reductions
96.9 109.7 12.9 74.7 61.8

NOx Target Level and Projected Emissions for the 15% RFP Plan

2008 NOx Emissions (tons/day) 13-County NOx

Target Level Projected 13-County NOx Inventory Tons over 13- County Target Available 7-County NOx Reductions Excess Nonattainment Area NOx Reductions
441.2 445.5 4.3 128.1 123.8

21.0 INTRODUCTION

Section 182 of the federal Clean Air Act Amendments of 1990 (CAA) requires ozone nonattainment areas with air quali ty classified as "moderate" or worse to submit plans showing reasonable further progress towards attainment of the national ambient air quality standards (NAAQS). Because Atlanta was classified as a "serious" nonattainment area under the 1-hour ozone standard, the CAA required Georgia to de velop a state implementation plan (SIP) to reduce emissions of volatile organic compounds (VOCs) in the 13-county Atlanta 1-hour ozone nonattainment area by 15% from 1990 to 1996. Th e last revision to Georgia's 15% Rate-ofProgress (ROP) SIP (the 15% Plan) was subm itted by the Georgia Environmental Protection Division (EPD) on June 17, 1996, and was appr oved by the United States Environmental Protection Agency (EPA) effective May 26, 1999 (64 FR 20196, April 26, 1999).

The CAA also requires Post-1996 emission reducti ons of VOCs and/or nitrogen oxides (NOx) totaling 3% per year, averaged over each cons ecutive three-year period beginning in 1996 and continuing through the attainment date. Geor gia chose to rely solely on NOx emission reductions in its Post-1996 ROP SIP (the 9% Plan ). This plan was required to describe how Georgia would achieve reasonabl e further progress towards a ttaining the 1-hour ozone NAAQS between 1996 and 1999, the attainment deadline fo r serious nonattainment areas. The last revision to Georgia's 9% Plan was submitted June 17, 1996, and was approved by EPA effective April 19, 1999 (64 FR 13348, March 18, 1999).

On July 17, 2001, EPD submitted to EPA the Atla nta 1-hour ozone attainment SIP, which
included a demonstration that Atlanta would attain the 1-hour ozone NAAQS by November 15, 2004. That attainment demonstration, including the extension of the attainment date, was approved by the EPA in a no tice published in the Federal Register on May 7, 2002 (67 FR 30574), which cited EPA's policy to grant attainme nt date extensions for areas dependent upon upwind states' emission reductions mandated by the regional NOx SIP Call as a basis for approval. Subsequently, in challenges to othe r attainment date extensions, several federal appeals courts ruled that EPA lacked the authority to grant such attainment date extensions. On February 20, 2003, EPA filed a motion for voluntar y vacatur of Atlanta' s attainment date extension and approval of Atlanta's ozone attainment demonstration. On June 16, 2003, the United States Court of Appeals for the Eleventh Circuit issued an or der granting EPA's motion, thereby vacating approval of the July 17, 2001, attainment demonstration.

In response to these court rulings, EPA issued a final rulemaking action in the September 26, 2003, Federal Register (68 FR 55469). It included a determin ation that the Atlanta area had failed to attain the 1-hour ozone standard by the statutory deadline of November 15, 1999, and that by operation of law, the Atlanta area wa s being re-classified as a "severe" ozone nonattainment area effective January 1, 2004. Unde r Section 181(a)(1) of th e Clean Air Act, the
attainment deadline for Atlanta as a new "sever e" nonattainment area was "as expeditiously as practicable," but not later than November 15, 2005.

Georgia EPD subsequently conducted an Early A ttainment Assessment to review the progress made in implementing the July 17, 2001, ozone attainment SIP. The Early Attainment
Assessment indicated that the emission reduction s achieved from the 1-hour ozone attainment

3SIP control measures had been effective in re ducing monitored levels of ozone and that the attainment demonstration previously appr oved by EPA for the Atlanta 1-hour ozone
nonattainment area while classifi ed as "serious" was still a va lid technical demonstration of
attainment under the "severe" classification. Fo r this reason, EPD requested that EPA consider the July 17, 2001, attainment demons tration as a "severe" area at tainment demonstration, thereby establishing November 15, 2004, as the "as expeditiously as practicable" attainment date for the
Atlanta "severe" ozon e nonattainment area.

EPA's September 26, 2003, action required submissi on of a severe area Post-1999 ROP SIP. A
severe area Post-1999 ROP SIP must describe how at least a 3 percent per year reduction in emissions of ozone precursors (VOCs or NOx) will be achieved, from the time of failure to meet
the "serious" area attainment da te (November 15, 1999) until the "sev ere" area attainment date.

The Atlanta severe area Post- 1999 ROP SIP contained a descript ion of how the 3 percent per year reductions in ozone precursor emissions , required over the period from November 15, 1999, through November 15, 2004, were achieved. It also contained motor vehicle emission budgets (MVEBs) for the Atlanta 1-hour ozone nonattainment area. EPD submitted the Post-1999 ROP SIP and MVEBs on December 24, 2003, and they were approved by EPA effective August 18, 2004 (69 FR 42880, July 19, 2004).

On April 30, 2004, EPA designated 20 metropol itan Atlanta counties as a "marginal"
nonattainment area under the 8-hour ozone standa rd. The eight-hour ozone nonattainment area encompasses the 13 counties of the former 1-hour ozone nonattainment area plus seven additional "ring" counties: Ba rrow, Bartow, Carroll, Hall, Newton, Spalding, and Walton. With an attainment deadline of June 15, 2007, marginal areas were required to attain the National Ambient Air Quality Standard (NAAQS) by the 2006 ozone season. Because monitoring data
from the 2006 ozone season indicated that Atlant a had not attained the NAAQS, the area was
reclassified 3 to "moderate," with an attainment date no later than June 15, 2010.

In ozone nonattainment areas with air quality cl assified as "moderate" or worse, the reasonable further progress (RFP) 4 requirement established in Section 182(b) of the Clean Air Act (CAA) prescribes emission reductions from the baseline to taling 15% within six years of the base year (i.e., by the end of 2008 for the 8-hour oz one NAAQS). Per 40 CFR Part 51.910(a)(1)(iii), moderate and higher classificat ion areas of which a portion has an approved 1-hour ozone 15%
VOC Plan can choose to treat th e nonattainment area as two part s, each with a separate RFP target, and may substitute reductions in NOx for VOCs in the sub-area with the approved 15% Plan. The 15% reduction for the sub-area wit hout an approved 1-hour ozone 15% VOC Plan must be entirely in VOCs. Because photoche mical air quality modeling indicates that NOx
reductions are more effective than VOC reductio ns in reducing ozone concentrations in the region, 5 Georgia will rely solely on NOx emission reductions for the 13-county part of the Atlanta ozone nonattainment area with an approved 15% VOC Plan.

3 73 Federal Register 12013, March 6, 2008

4 The terminology EPA uses for progress towards attainment has been codified at 40 CF R Part 51.900: “reasonable further progress" is used for the 8-hour ozone NAAQS, “rate of progress" is used for the former 1-hour NAAQS.

5 See Appendix A, Sensitivity of ozone concentrations in Atlanta to NOx and VOC controls inside and outside the nonattainment area ( www.gaepd.org/Files_PDF/plans/sip/app_a_ nox_substitution_and_out_o f_area_benefits.pdf )

42.0 PLAN REQUIREMENTS

This plan was prepared in accordance with the SIP requirements established in the Code of Federal Regulations (40 CFR Part 51), and with the EPA guidance cited in Section 3.2.1 below. The plan is consistent with ex isting guidelines for implementati on plans and contains a detailed analysis of each of the following required elements of a reasonable-further-progress plan:

• Base Year Emissions Inventories

• Target Level Calculations

• Control Measures

• Projected Emissions

• Motor Vehicle Emissions Budgets

• Milestone Failure Contingencies

• Reporting Requirements

53.0 8-HOUR OZONE 15% REASONAB LE FURTHER PROGRESS PLAN

3.1 Introduction

This Atlanta 8-Hour Ozone 15% Reasonable Furt her Progress Plan, here inafter called the 15% RFP Plan, is not required nor intended to dem onstrate attainment of the ozone NAAQS. The 15% RFP Plan is a description of how the 15% emissions reductions required by 2008 were
achieved.

In order to develop the 15% RFP Plan, Geor gia EPD worked with the Atlanta Regional Commission to update the 2002 VOC and NOx em issions inventories and adjusted the inventories by removing VOC and NOx already scheduled for control by previous federal regulations on motor vehicles and gasoline vol atility. The required VOC and NOx reductions (15%) and the resulting target levels of futu re emissions were calcu lated, and growth in emissions was estimated. Projected 2008 emissi ons reflect various emissions control rules already adopted and implemented prior to the 2008 ozone season. Alth ough projected emissions for 2008 are above the target levels calculated for 7-county VOC and 13-county NOx, with VOC reductions from the 13-county area and NOx re ductions from the 7-county area the 15% emissions reductions required in th e Atlanta area by 2008 are achieved.

Note that, while all appendices have been s ubmitted in printed form, any supporting files and databases that would be impracticable to prin t are available electronically, both on the submitted CD-R and via permanent EPD web links. In addition, files are perman ently archived on EPD computer networks. To request access to any of these files please contact the Georgia EPD Air Protection Branch at (404) 363-7000.

3.2 Calculation of Emission Target Levels

3.2.1 Procedure for Development of Target Levels

The 15% RFP Plan was prepared following the guidance in:

• Appendix A to Preamble - Methods to A ccount for Non-Creditable Reductions When Calculating ROP Targets for the 2008 and Later ROP Milestone Years ("the 8-hour ozone RFP guidance") 6 ;

• EPA's December, 1993, NOx Substitution Guidance 7

• The August 15, 2006, 8-hour ozone RFP guidance me mo from William T. Harnett, Director of EPA's Air Quality Policy Division; and

• EPA's Policy Guidance on the Use of MOBILE6 for SIP Development and Transportation Conformity 8 (the "MOBILE6 policy guidance").

6 70 FR 71696-71697, November 29, 2005; corrected October 4, 2006 (71 FR 58498)

7 http://web.archive.org/web/20041011225913/http://www .epa.gov/ttn/oarpg/t1/memoranda/noxsubst.wpd

8 http://www.epa.gov/otaq/mode ls/mobile6/m6policy.pdf

6The 8-hour ozone RFP guidance provides step-by-st ep procedures for calc ulating the 2008 target level emissions. This methodology was used to calculate 2008 target levels. The projected inventory for an RFP milestone year with all cont rol measures in place and reflecting any growth in activity projected to occur by the milestone year must be equal to or less than the target level of emissions for that milestone year.

The Reasonable-Further-Progress Inve ntory is the base inventory from which the target levels of emissions for the milestone years must be calcul ated. These target leve ls reflect the required percent reductions, net of growth, from base year emissions that must be achieved to meet the requirements of the CAA. For this 15% RFP SIP, the target levels reflec t the required 15 percent reductions for reasonable further progress.

3.2.2 2002 Reasonable-Further-Progress Base Year Inventories

The 2002 Reasonable-Further-Progress Base Ye ar Inventories are comprised of the anthropogenic 9 point, area, nonroad, and mobile s ources in the 20-county 8-hour ozone nonattainment area. Note that throughout this SI P revision, its appendices, and its exhibits, the
term "mobile" is used to describe emissions from on-road motor vehicles, while the term
"nonroad" is used to describe emissions from off-road equipment and vehicles. The 2002 RFP
Base Year Inventories include emissions from th e mobile and the nonroad sectors that have been updated using the latest models 10 and, for mobile sources, revised 11 2002 vehicle activity estimates from a new 20-county travel demand m odel for the region. The development of the 2002 inventories for area, aircraft and locomotive, and point sources (exc luding power plants) is documented in Appendix E, Documentation of VISTAS In ventories and Georgia 2002 CERR Inventory . For the 2002 power plant emissions inve ntory, actual emissions data from EPA's Continuous Emissions Monitoring System (CEMS) da tabase were used, as further described in the second paragraph following, and in Secti on 5.4.1. The development of the 2002 mobile source emissions inventory is documented in Appendix C, Mobile Source Emissions Modeling for Atlanta 15% RFP Plan.

Per 40 CFR Part 51.910(a)(iii)(B), for moderate and higher classi fication areas of which only a portion has an EPA-approved 15% VOC reduction plan, the state can treat the nonattainment area as two parts, each with a se parate RFP target. Georgia has chosen that approach. Because
ozone concentrations in the Atlanta area are much more sensitive to reductions in NOx than in VOC emissions, NOx emission reductions are bei ng relied upon for progress towards attainment in the 13-county area for which the statutory requirement for VOC reductions has already been met. For the 7-county part of the 20-count y nonattainment area, VOC reductions are still required. Accordingly, two separate 2002 RFP Base Year Inventories were developed for this 15% RFP SIP, one each for the 13-county and 7-county parts of Atlanta's 20-county ozone
nonattainment area.

9 (resulting from human activity)

10 MOBILE6.2.03 and NONROAD2005, respectively

11 According to the MOBILE6 policy guidance, “If SIPs are revised ..., base year...motor vehicle emission
inventories will need to be recalculated with the latest available planning assumptions... Base year...inventories
should use the best data available for those years."

7The updated 2002 RFP NOx emissions inventory for the 13-county portion of the Atlanta 8-hour ozone nonattainment area is approximately 562.1 tons per day (See Table 1 below -- due to spreadsheet rounding, totals may differ sl ightly from the sum of the parts).

Table 1 -- 13-County 2002 Reasonable-Furth er-Progress Base Year NOx Inventory

2002 NOx Emissions (tons/day)

Point Area Nonroad Mobile Total 13-county 2002 RFP Base Year Inventory 84.1 24.5 111.3 342.1 562.1

Because the seven "ring" coun ties in the 20-county Atlanta ozone nonattainment area are not included in Georgia's approved 15% Plan for the 1-hour ozone sta ndard, as part of a moderate ozone nonattainment area they are subject to the 15% VOC reduction requirement in Section 182(b)(1) of the CAA. To m eet this requirement, VOC reduc tions from the 7-county and 13- county parts of the nonattainment area were relied upon for progress to wards attainment.

Table 2 -- 7-County 2002 Reasonable-Further-Progress Base Year VOC Inventory

2002 VOC Emissions (tons/day)

Point Area Nonroad Mobile Total 7-County 2002 RFP Base Year Inventory 6.4 50.8 15.9 50.5 123.5

3.2.3 Adjusted Base Year Inventories

Adjusted Base Year Inventories must be calcu lated relative to the RFP milestone year. As detailed in the 8-hour ozone RFP guidance, th e development of the Adjusted Base Year Inventories requires excluding from those inventories the emissi on reductions that would occur by the milestone years as a result of federal pr ograms already mandated prior to the 1990 Clean
Air Act Amendments.

The adjustments exclude:

• Emissions reductions that would occur by the mile stone year as a result of the Federal Motor Vehicle Control Program (FMVCP) promulgate d prior to the Clean Air Act Amendments;
and

• Reductions that would result by the milestone ye ar from the federal Reid Vapor Pressure (RVP) regulations promulgated in June 1990.

8These adjustments are made because states ar e not allowed to take credit for emissions
reductions that would have occurred due to fleet turnover from ve hicles meeting pre-1990
standards to newer cars and trucks , or from previously existing fe deral fuel regulations. These non-creditable reductions are called the FMVCP/RVP reductions. See Appendix C, Exhibits 5 and 8, for details on the Adjusted Base Year I nventories. Tables 3 and 4 below show the
FMVCP/RVP reductions.

Table 3 -- 13-County FMVCP/RVP Reductions

13-county area Mobile Source NOx emissions (tons/day) Mobile Source VOC emissions (tons/day) FMVCP/RVP NOx reductions (tons/day) FMVCP/RVP VOC reductions (tons/day)2002 w/o post1990 CAA

measures 401.3 256.3 --- ---

2002 adjusted to
2008 358.2 227.2 43.1 29.1

Table 4 -- 7-County FMVCP/RVP VOC Reductions

7-county area Mobile Source VOC emissions (tons/day) Mobile Source NOx emissions (tons/day) FMVCP/RVP VOC reductions (tons/day) FMVCP/RVP NOx reductions (tons/day2002 w/o post1990 CAA

measures 64.0 72.8 --- ---

2002 adjusted to
2008 54.5 65.8 9.6 6.9

The 2002 Adjusted Base Year Inventories were prepared using MOBILE6.2 emission factors; 2002 speeds 12 and vehicle miles traveled (VMT) da ta from ARC's travel demand model networks; and area-specific fleet age 13 distributions. The Adjusted Base Year inventory calculation procedure described in the 8-hour ozone RFP guida nce was used. The 13-county 2002 Base Year NOx Inventory Adjusted to 2008 to tals 519.0 tons per day, as shown in Table 5. The 7-county 2002 Base Year VOC Inventory Adju sted to 2008 totals 114.0 tons per day, as
shown in Table 6.

Table 5 -- 2002 Adjusted to 2008 Base Year 13-County NOx Inventory

NOx Emissions (tons/day) 13-County NOx Point Area Nonroad Mobile Total Adjusted Base Year Inventory 84.1 24.5 111.3 299.1 519.0

12 See Appendix C.

13 See Section 6.2 and Appendix C.

9Table 6 -- 2002 Adjusted to 2008 Base Year 7-County VOC Inventory

VOC Emissions (tons/day) 7-County VOC Point Area Nonroad Mobile Total Adjusted Base Year Inventory 6.4 50.8 15.9 40.9 114.0

3.2.4 Required Emissions Reductions

To calculate the required NOx emissions reduction in tons per day, the 13-county Adjusted Base Year Inventory adjusted to the RFP target year is multiplied by 15 percent. The required NOx
reductions for 2008 are shown in Table 7.

Table 7 -- Required 13-County NOx Reductions for 2008

Adjusted Base Year Inventory 519.0 tons/day Times Factor (15%) × 0.15 Emissions Reduction Required 77.9 tons/day

To calculate the required VOC emissions reduction in tons per day, the 7-county Adjusted Base Year Inventory adjusted to the RFP target year is multiplied by 15 percent. The required VOC reductions for 2008 are presented in Table 8.

Table 8 -- Required 7-County VOC Reductions for 2008

Adjusted Base Year Inventory 114.0 tons/day Times Factor (15%) × 0.15 Emissions Reduction Required 17.1 tons/day

3.2.5 Target Levels of Emissions

To calculate the 2008 NOx target emissions level, the reductions necessary to meet the required 15 percent emissions reduction a nd the FMVCP/RVP non-creditable re ductions were subtracted from the 13-county 2002 RFP NOx inventory. The results, in NOx tons per day, are shown in Table 9 below:

Table 9 -- NOx Emissions Target Level for 2008, 13-County Area

2002 13-county NOx RFP inventory 562.1 tons/day FMVCP/RVP reductions (2002 to 2008)

− 43.1 tons/day Adjusted Base Inventory 519.0 tons/day Required Reduction (15% of Adjusted Base)

− 77.9 tons/day NOx Target Level for 2008 441.2 tons/day

To calculate the 2008 VOC target emissions level, the reductions necessary to meet the required 15 percent emissions reduction a nd the FMVCP/RVP non-creditable re ductions were subtracted

10from the 7-county 2002 RFP VOC inventory. The re sults, in VOC tons per day, are shown in
Table 10 below:

Table 10 -- VOC Emissions Target Level for 2008, 7-County Area

2002 7-county VOC RFP inventory 123.5 tons/day FMVCP/RVP reductions (2002 to 2008)

− 9.6 tons/day Adjusted Base Inventory 114.0 tons/day Required Reduction (15% of Adjusted Base)

− 17.1 tons/day VOC Target Level for 2008 96.9 tons/day

114.0 CONTROL MEASURES

This section describes the control measures being relied upon for this 15% RFP Plan. The projected emissions reflect federa l and/or state emission controls on all emission sour ce sectors. All non-federal control measur es being relied upon for this 15% RFP Plan have been implemented and have been codified in Georgia's state regulations. See Rules for Air Quality Control Chapter 391-3-1 and Rules for Enhanced Inspection and Maintenance Chapter 391-3-20.

4.1 Point Source Control Measures

For demonstrating progress in the 13-county area for which the 15% VOC reduction requirement has already been met, NOx emission reductions are being relied upon for this 15% RFP Plan because photochemical air quality modeling indicates that, on a parts-per-billion per ton basis,
NOx reductions are more effective than VOC reduc tions in reducing ozone concentrations in the region. Georgia EPD is including reductions of NOx emissions at coal-fired electrical power plants in the 20-county nonattainment area. As a control strategy to attain the 1-hour ozone standard in Atlanta, stricter controls have been placed on these power plants. 14

, 15 Emissions from nonattainment area power plants are discu ssed in section 5.4.1, below. Note that although sensitivity analyses indicate that reducing NOx emissions from power plants as far away as Putnam and Monroe counties (Plants Branch and Scherer, respectively) results in significant reductions in ozone concentrations in central Atlanta (e.g., 1.8 parts per billion from NOx controls at Plant Scherer), 16 no emissions reductions outside th e Atlanta nonattainment area are being relied upon for RFP credit.

State regulation 17 establishes May through September NOx emission limits on coal-fired electric generating units (EGUs) within the counties of Bartow, Ch erokee, Clayton, Cobb, Coweta, DeKalb, Douglas, Fayette, Floyd, Forsyth, Fult on, Gwinnett, Heard, He nry, Monroe, Paulding, Putnam, and Rockdale. Compliance with this state regulation is ach ieved, in part, by the installation and operation of combustion modification and/or ai r pollution contro l equipment.
Combustion modifications includ e the use of over-fire air and low-NOx burners. Air pollution control consisted in selective catalytic reduc tion (SCR). See Appendix D for details of the combustion modifications and/or SCR use placed on some of the large EGUs in the counties
noted above. 18

14 Georgia’s State Implementation Plan for the Atlanta Ozone Non-attainment Area , Section 3.2.1.1.2, July 17, 2001, http://permanent.access. gpo.gov/websites/www.dnr.state .ga.us/dnr/environ/ plans_files/plans/sip_narrative.pdf

15 Appendix D, Controls on Large Electric Utility Steam Generating Units, http://www.gaepd.org/Files_PDF/plans/sip/app_d_egu_controls.pdf

16 Appendix A, p. A-3 ( http://www.gaepd.org/Files_PDF/plans/sip/app_a_ nox_substitution_and_out _of_area_benefits.pdf )

17 See Rules for Air Quality Control, Chapter 391-3-1- .02(2)(jjj), NOx Emissions from Electric Utility Steam Generating Units, http://www.gaepd.org/Files_PDF/rules/rules_exist/391-3-1.pdf

18 Of these counties, all but Floyd, Heard, Monroe, and Putnam are in the Atlanta ozone nonattainment area.

124.2 Area Source Control Measures

The projected area source emissions reflect Georgia's ban 19 on open burning in the nonattainment area during the 2002 ozone season. This rule was instituted for the 15% and 9% Plans. Stage I gasoline vapor reco very is also reflected in the 13- county area source inventories.

4.3 Nonroad Mobile Source Control Measures

The projected 2008 nonroad emissions reflect all a pplicable federal controls on nonroad mobile sources, as well Georgia's controls 20 on gasoline.

4.4 Mobile Source Control Measures

The projected mobile source emi ssions inventories described in Section 5.4 below reflect all
federal and state mobile source control rules. C ontrols that only apply in the 13-county part of
the Atlanta 8-hour ozone nonattai nment area include annual enhanced vehicle inspection and
maintenance 21 (I/M) with onboard diagnostics system checks on 1996 and newer model year cars and light trucks; 2-mode ASM tests on 25-yea r-old through 1995 model year vehicles; a check for catalytic converter tamper ing on 25-year-old through 1995 m odel year vehicles; a gas cap pressure test on all subject vehicles; and tech nician training and certi fication; and Stage II gasoline refueling vapor recovery. Controls that apply in both the 13-county and the 7-county parts of the nonattainment area include low-su lfur and low (7.0 pounds per square inch) RVP gasoline; 22 the Federal Motor Vehicle Control Progra m, including Tier 1 and (beginning with 2004 models) Tier 2 tailpipe standards; a nd the National Low Em ission Vehicle (NLEV)

program.

See Section 5.4.4, Section 6, and Appendix C for fu rther discussion of mobile source modeling.

19 See Rules for Air Quality Control, Ch apter 391-3-1 -.02(5), Open Burning, http://www.gaepd.org/Files_PDF/ rules/rules_exist/391-3-1.pdf

20 See Rules for Air Quality Control, Chapter 391-3-1-.02(2)(bbb), Gasoline Marketing, http://www.gaepd.org/Files_PDF/ rules/rules_exist/391-3-1.pdf

21 See Rules for Enhanced Inspection and Maintenance, Chapter 391-3-20, http://www.gaepd.org/Files_PDF/ rules/rules_exist/391-3-20.pdf

22 See Appendix B, EPA Approval of Georgia Gasoline Control Program ( http://www.gaepd.org/Files_PDF/plans/sip/app_b_epa_approval_of_georgia_gasoline_control_program.pdf )

135.0 PROJECTED EMISSIONS

5.1 Emissions Projection Overview

With the exceptions of mobile sources a nd the nonroad sources included in NONROAD2005, which were explicitly modeled 23 for the target year; and power plant emissions; 2008 emissions were projected by interpolat ing between 2002 and 2009 summer 24 daily emissions extracted from the "BaseG" county-level emissions inve ntories prepared by contractors for VISTAS, 25 the regional planning organization of which Georgia is a member . VISTAS has been funding the development of one base year (2002) and two fu ture year (2009 and 2018) emissions inventories for the past several years. Preparation of the VISTAS inventories is de scribed in Appendix E, Documentation of VISTAS Inventories and Georgia 2002 CERR Inventory

. 26 The general approach adopted by VISTAS was to use recently updated growth and control data from sources
that included EPA's Clean Air Interstate Rule analyses; EPA's Heavy Duty Diesel rulemaking emission projections; EPA's Economic Growth Analysis System (EGAS 5.0); an updated Regional Economic Models, Inc. (REMI), Poli cy Insight® model (version 5.5, used in the development of EGAS 5.0); and the latest Annual Energy Outlook published by the Department of Energy. See Appendix E for more details. Th e resulting emissions in ventories represent the best currently available estimate of past and future year emissions in Georgia. EPD has conducted analysis that shows gr owth factors generated by EGAS, and aggregated by SCC and by county, follow a linear trend. The estimated cha nge in emissions for interim years, linear in nature, obtained through inter polation of the quality-assured 2002 and 2009 VISTAS emission
inventories is consistent with this finding. EPD considers it unlikely that use of a methodology other than interpolation would l ead to significantly diffe rent or "better" 2008 inventories. EPD thus considers interpolation an appropriate technique to estimate emissions for 2008.

The VISTAS contractors processed the inventories using EPA's Sparse Matrix Operator Kernel Emissions (SMOKE) 27 modeling system. County-level dail y emission files were generated for 2002 and 2009 from the earlier BaseF VISTAS i nventories using the program SMKREPORT. EPD used these county-level daily emission file s to calculate annual-av erage-day to summeraverage-day conversion factors (r atio of the average summer emissions to average annual emissions). EPD then derived county-level summer-day emission estimates (defined as the average of all days in June, Ju ly and August) from the annual average daily BaseG emissions by multiplying those annual average daily emissions times the annual-to-summer day conversion factors derived from the VISTAS BaseF SMKREPORT outputs:

⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛

= annual
BaseF summer BaseF annual
BaseG summmer BaseG E E EE

23 The 2008 mobile and NONROAD2005 inventories reflect an assumed 100% market share of 10% ethanol-blend gasoline (E10), with a volatility waiver that, per Georgia's Gasoline Marketing Rule, allows RVP for E10 to rise as high as 8.0 pounds per square inch.

24 June, July, and August

25 Visibility Improvement State and Tribal Association of the Southeast

26 http://www.gaepd.org/Files_PDF/plans/sip/app_e_vistas_inventory_documentation_b_and_f.pdf

27 http://www.smoke-model.org/index.cfm

14summmer BaseG E = Daily summer BaseG emissions averaged over all days in June, July and August

annual
BaseG E = Daily annual BaseG emissions averaged over all 365 days

summer BaseF E = Daily summer emissions averaged over all days in June, July and August extracted from the SMKREPORT output generated duri ng VISTAS BaseF4 emissions processing

annual
BaseF E = Daily annual emissions averaged over all 365 days extracted from the SMKREPORT output generated during VISTAS BaseF4 emissions processing

The only change made between the BaseG inventor ies used for this SIP and the BaseG4 "bestand-final" inventories was to power plant emissi ons. As explained in Section 5.4.1 below, the only use made of VISTAS power plant emission s for this SIP was in calculating NOx-to-VOC
conversion factors. These would not be expected to change if deri ved from BaseG4 inventories. The projected emissions for the 2008 target year are summarized in Excel workbooks available
here:

http://www.gaepd.org/Files_XLS/plans/sip/ 20-county_RFP_targets_and_emissions_rev3.xls

5.2 Projected 7-County 2008 VOC Emissions Summary

Projected 7-county 2008 VOC emissions reflecting the control measures described in Section 4, Control Measures, are summarized in Table 11:

Table 11 -- 2008 7-County Pr ojected VOC Emissions

VOC Emissions (tons/day)

Point Area Nonroad Mobile Total 2008 7-County Projected VOC Inventory 6.7 49.1 12.9 41.1 109.8

Although the projected 7-county 2008 VOC emissi ons of 109.8 tons per day are above the 2008 7-county VOC Target Level Emissions of 96.9 t ons of VOC per day by 12.9 tons per day, as
shown in Table 12 below there are unclaimed 2008 VOC reductions totaling 74.6 tons per day available from the 13-county part of the nonatt ainment area for which there is an approved 1- hour ozone 15% VOC Plan. By applying 12.9 tons per day of those available 13-county VOC reductions towards 7-county RFP, the 7-count y VOC target is met, with 61.7 available nonattainment area VOC tons per day reductions remaining.

15Table 12 -- 2008 13-County Available VOC Reductions

VOC Emissions (tons/day)

Point Area Nonroad Mobile Total 2002 Adjusted to 2008 Base Year 13- County VOC Inventory 15.9 297.8 137.7 145.1 596.4

2008 13-County Projected VOC Inventory 14.5 269.2 107.4 130.7 521.8

2008 13-County Available VOC
Reductions 1.4 28.6 30.3 43.5 74.6

5.3 Projected 13-County 2008 NOx Emissions Summary

The projected 13-county 2008 NOx emissions refl ecting the control measures described in Section 4, Control Measures, are summarized in Table 13:

Table 13 -- 2008 Projected 13-County NOx Emissions

NOx Emissions (tons/day)

Point Area Nonroad Mobile Total 2008 Projected 13-County NOx Inventory 99.9 25.2 104.3 221.2 450.7

Although the projected 13-county 2008 NOx emissi ons of 450.7 tons per day are above the 2008 13-county NOx Target Level Emissions of 441.2 t ons of NOx per day by 9.5 tons per day, as
shown in Table 14 below there are unclaimed 2008 NOx reductions totaling 126.0 tons per day available from the 7-county part of the nonatt ainment area without an approved 1-hour ozone 15% VOC Plan, where RFP must be in VOC reduc tions. By applying 9.5 tons per day of those available 7-county NOx reductions towards 13-c ounty RFP, the 13-county NOx target is met,
with 116.5 available nonattainment area NOx tons per day reductions remaining.

Table 14 -- 2008 7-County Available NOx Reductions

VOC Emissions (tons/day)

Point Area Nonroad Mobile Total 2002 Adjusted to 2008 Base Year 7- County NOx Inventory 163.1 7.8 18.1 59.0 247.9

2008 7-County Projected NOx Inventory 46.7 8.0 15.7 51.5 121.9

2008 7-County Available NOx
Reductions 116.4 -0.2 2.3 7.5 126.0

165.4 Emissions Projection Methodology by Source Category

5.4.1 Point Source Emissions Projections

There are two major types of point sources: electric generating unit (EGU) point sources and all other (non-EGU) point sources. For the 2002 Ba se Year Inventory, NOx emissions from EGU point sources were obtained from actual emissions data 28 reported by Georgia Power Company
to EPA's CEMS database. Note that these ac tual EGU data for 2002 reflect the effects of controls in operation on several units at Georgia Power's Plants Bowen, McDonough, and Yates during the May through September, 2002. For nona ttainment area EGU VOCs, facility-level, summer-day emissions were computed by multiplying the 2002 actual and 2008 projected summer-day EGU NOx emissions of individual facilities by site -specific NOx-to-VOC conversion factors. Facility-level daily emission files for 2002 and 2009 produced by SMKREPORT during the processing of the VISTAS BaseF4 emissions were used to calculate site specific NOx-to-VOC conversio n factors (ratio of the average summer VOC emissions to average summer NOx emissions). 29 The 2002 NOx-to-VOC conversion factors were used with
the 2002 actual EGU NOx emissions. Because no additional EGU controls will be added between 2008 and 2009, the 2009 NOx-to-VOC conve rsion factors were used with the 2008 projected EGU NOx emissions.

Non-EGU point source emissions estimates for 2002 and 2009 were extracted from the VISTAS inventories for the 20-county Atlanta 8-hour ozone nonattainment area. Non-EGU point source
emissions inventories for 2008 were devel oped by interpolating between 2002 and 2009 nonEGU point source emissions inventories for th e 20-county Atlanta 8-hour ozone nonattainment area. The 2008 inventories for the EGUs in the 20-county nonattainment area were actual NOx emissions from those plants 30 from the CEMS database.

5.4.2 Area Source Emissions Projections

Area source emissions inventories for 2008 were developed by interpolating between the 2002 and 2009 summer-day emissions extracted from the VISTAS BaseG area source emissions inventories for the 20-county Atlanta 8-hour ozone nonattainment ar ea (see Section 5.1).

5.4.3 Nonroad Mobile Source Emissions Projections

Nonroad mobile source emissions for 2002 and 2008 were, with the exception of those from aircraft and locomotives, calculated by EP D using EPA's NONROAD2005 emissions model. 31

The NONROAD model reflects the effects of all fe deral controls, and of Georgia Gasoline and E10, on nonroad sources of emissions. Inve ntory methodology for 2002 and 2009 emissions

28 http://camddataandmaps.epa.gov/gdm/index.cfm?fuseaction=emissions.wizard

29 See Column L of the "egu_by_facility" worksheet in the Excel workbook "20- county_RFP_targets_and_emissions_rev3.xls" available here: http://www.gaepd.org/Files_XLS/plans/sip/20- county_RFP_targets_and_emissions_rev3.xls

30 see the "egu_nox_summer_02-08" worksheet in the Excel workbook "20- county_RFP_targets_and_emissions_rev3.xls" available here: http://www.gaepd.org/Files_XLS/plans/sip/20- county_RFP_targets_and_emissions_rev3.xls

31 http://www.epa.gov/otaq/nonrdmdl.htm#model

17from aircraft and locomotives is described in Appendix E, Documentation of VISTAS Inventories and Georgia 2002 CERR Inventory. Total nonroad inventorie s for 2008 were developed by adding the directly modeled 2008 emissions for sources included in the NONROAD2005 model to those interpolated between the 2002 a nd 2009 summer-day emissions for aircraft and
locomotives extracted from the VISTAS BaseG inventories.

5.4.4 Mobile Source Emissions

The highway mobile source emissions for the 20 -county 8-hour ozone nonattainment area were developed using the MOBILE 6.2 emission factor model 32 and the ARC's link-based emissions estimation procedure. See Appendix C for de tails of the mobile source emissions modeling. The projected mobile source emi ssions inventories reflect all fe deral and state mobile source control rules, including federal tailpipe standards, low-sulfur a nd low-RVP gasoline, and, in the
13 counties of the former 1-hour ozone standard nonattainment area, enha nced I/M and Stage II refueling vapor recovery.

One adjustment had to be made to the calculated tons per day emissions inventories to arrive at
the final motor vehicle emissions inventories. This adjustment accounts for the loss of credit from a state rule allowing exemption from ve hicle inspection and maintenance for cars 10 years old or older driven fewer than 5,000 miles per year and owned by persons 65 years old or older.
It was estimated that this senior I/M exemption increas ed VOC and NOx emissions by 0.05 and 0.03 tons per day, respectively, in 2002. This se nior I/M exemption emissions debit for 2002 is conservatively high and was also added to the 2008 budget year inventorie s. See "Effect of Senior Exemption on 2002 Highway Mobile Source Emissions" in Appendix F for details of the senior exemption cred it loss calculations.

32 http://www.epa.gov/otaq/m6.htm#m60

186.0 MOTOR VEHICLE EMISSIONS BUDGETS

6.1 Background

Reasonable-Further-Progress plans are control stra tegy SIP revisions. As such, they establish motor vehicle emissions budgets (MVEBs). A mo tor vehicle emissions budget is described in EPA's transportation conformity rule 33 as "...the implementation plan's estimate of future [motor vehicle] emissions." Such budgets establis h caps on motor vehicle emissions; projected emissions from transportation plans and programs must be equal to or less than these caps for a positive conformity determination to be made.

Section 93.118(e)(4)(iv) of the transportation conformity rule requires that the "motor vehicle emissions budget(s), when considered together w ith all other emissions sources, is consistent with applicable requirements for reasonable fu rther progress, attainment, or maintenance...."

Section 93.118(e)(4)(v) of the transportation conformity rule requires that "the motor vehicle emission budget(s) is consistent with and clearl y related to the emissi ons inventory and the
control measures in the submitted control strate gy implementation plan revision or maintenance plan...."

6.2 Establishment of 2008 Motor Vehicle Emissi ons Budgets for the Atlanta 8-hour Ozone
Nonattainment Area

Note that the motor vehicle emissions budgets be ing established with this 15% RFP Plan are essentially the 2008 mobile source emission inventories for the Atlanta nonattainment area and
do not include emissions from outside the nona ttainment area. Table 15 below shows the 2008
nonattainment area emissions i nventories for all sectors:

Table 15 -- 2008 20-County Atlanta Nonatta inment Area Projected Emissions

Point Area Nonroad Mobile Total VOC (tons/summer day) 21.1 318.3 120.3 171.78 631.5 NOx (tons/summer day) 139.4 33.2 120.1 272.64 565.3

In preparation for this 15% RFP Plan, EPD work ed closely with the ARC to develop the best possible estimates of mobile so urce emissions for the 20-county Atlanta nonattainment area.
Mobile source inventories for 2008 were develo ped using the latest available planning assumptions, 34 the most recent recalibrated travel dema nd model, and EPA's latest motor vehicle emission factor model, MOBILE6.2.03. The 2008 mobile source emissions inventories developed for this 15% RFP Plan are the basis for new NOx and VOC budgets for 2008, ensuring that these new MVEBs are "consistent with applicable requir ements for reasonable

33 40 CFR Part 93.124(a)

34 e.g., separate registration distributions by age for the 13-county and 7-county parts of the 20-county nonattainment area; updated VMT and speeds from ARC's expanded and enhanced travel demand model

19further progress" and "consistent with and clearly related to the emissions inventory and the
control measures in the submitted contro l strategy implementation plan revision."

Although the 13-county emissions reductions being re lied upon for this 15% RFP Plan are from NOx controls alone, a 2008 inventory of 13-c ounty mobile source VOC emissions was also developed to provide a VOC budget for the entire 20-county nonattain ment area that reflects all latest planning assumptions. Similarly, although 7-county reductions ar e, per CAA Section 182, entirely VOC, a 2008 mobile source inventory of 7-county NOx was also developed. EPD worked with ARC to develop VOC and NOx emissi ons inventories for mobile sources using the ARC's link-based emissions estimation procedur e (see Appendix C). These mobile source
inventories reflect the most re cent planning assumptions and em ission factor model available, and the use of updated travel demand and emissi ons calculation models. The methodology used to calculate the highway mobile source emi ssions on which the update d 2008 MVEBs are based is discussed below and, in gr eater detail, in Appendix C.

The MOBILE6.2 motor vehicle emission factor model was used to calculate 2008 VOC and
NOx emission factors with all 2008 mobile source control rules in place. Two sets of emission factors were produced to properl y reflect different fleet characteristics and mobile source emissions controls in the 13-county and 7-count y parts of the 20-county nonattainment area.

The 13-county controls include: annual enhan ced I/M with onboard di agnostics system checks on 1996 and newer model year vehicles; 2-mode ASM tests on 25-model-year-old through 1995 vehicles; a check for catalytic converter tampering on 25-model- year-old through 1995 vehicles; a gas cap pressure test on all subject vehicl es; low-sulfur and low-RVP gasoline; Stage II gasoline refueling vapor recove ry; the Federal Motor Vehicle Control Program (FMVCP), including Tier 1 and (beginning with 2006 models) Tier 2 tailpipe standards; the National Low Emission Vehicle (NLEV) program; and tech nician training and certification.

For the 7-county part of the nonattainment area, the emission factors reflect Georgia's lowsulfur/low-RVP gasoline and all federa l controls (e.g., FMVCP, NLEV).

The emission factors resulting from the separa te MOBILE6.2 runs fo r the 13-county and 7- county parts of the 20-county nonattainment area were used with ARC's link-based emissions estimation procedure to calculate 2008 tons per day emissions in the following manner:

• For each of four times of day (a.m. peak, mi dday, p.m. peak, and night), the HPMS-adjusted and summer-adjusted 2008 VMT from each link in ARC's travel demand model were multiplied by the 2008 MOBILE6.2 emission fact or at the average speed closest to the congested-flow speed on that link.

• Emissions from all the links and all four time periods were summed together to get grams per day inventories, which were divided by 907,180 to convert from grams per day to tons per day.

These mobile source inventories reflect the most up-to-date mobile modeling assumptions, including 2008 VMT projected from a state-of-the-art travel demand model for the 20 counties

20and July 2008 emission factors from EPA's la test mobile source emission factor model,
MOBILE6.2.03. Details of the mobile source emissions modeling methodology, along with the MOBILE6.2 input files and othe r documentation, are in Appendi x C (Mobile Source Emissions Modeling for 15% RFP Plan).

Table 16 sums the calculated emissions i nventories for the 20-county Atlanta ozone nonattainment area and the 13-county seni or I/M exemption emissions increases.

Table 16 -- Total 20-County 2008 Motor Vehicle Emissions Budgets

VOC (tons/da y ) NOx (tons/day)
2008 Mobile Emissions Subtot al (MOBILE6.2 results) 171.78 272.64 Senior I/M Exemption Increases + 0.05 + 0.03 Total 2008 Motor Vehicle Emissions Budgets 171.83 272.67

This 15% RFP Plan hereby establishes 2008 motor vehicle emissions budgets of 171.83 and 272.67 tons per day, VOC and NOx, respectively, for the 20-county Atlanta 8-hour ozone nonattainment area. Interagency consultation am ong the relevant agencies occurred during the development of these MVEBs and prior to the submittal of this 15% RFP Plan. Full implementation plan documentation was provided to EPA, and EPA's stated concerns have been
addressed.

The MVEBs established by this 15% RFP Plan are based on new estimates of VMT and speeds from an updated, state-of-the-a rt travel demand model; on the la test version of EPA's motor vehicle emission factor model (MOBILE6.2.03); and on registration distributions by age developed using registration data 35 obtained from R.L. Polk & Company. These MVEBs are the
most accurate estimates of motor vehicle emissi ons developed to date for the Atlanta 8-hour
ozone nonattainment area.

35 Registration data was from R. L. Polk & Co.'s Nationa l Vehicle Population Profile ® current as of October 2002
and from R. L. Polk & Co.'s TIPNet ® current as of March 2003. See Appendix C, Exhibit 2, http://www.gaepd.org/Files_PDF/plans/sip/e xhibit_2_2002_registra tion_distributions.pdf , for more details on the registration distribution by age.

217.0 IMPLEMENTATION SCHEDULE

All control measures being relied on for this 15% RFP Plan were implemented no later than May 1, 2003, with the exception of the final phase of Georgia's low RVP/low-sulfur gasoline marketing rule, implemented September 16, 2003.

228.0 MILESTONE FAILURE CONTINGENCIES

As part of a 15% RFP Plan for a moderate oz one nonattainment area, Ge orgia is required to include a contingency plan identifying additional controls to be implemented in the event of a milestone failure. Contingency measures must be fully adopted rules or measures that will take effect without further action by the State or EPA if an area fails to make reasonable further progress by the applicable date.

EPA guidance 36 suggests that a contingenc y plan should include 3% of the Adjusted Baseline Inventory's emissions. The 2002 Adjusted-to- 2008 Baseline NOx Inventory for the 13-county area is 519.0 tons per day (see Table 5); a 3% contingency would be 15.6 NOx tons per day:

519.0 × 0.03 = 15.6

Section 5.3 of this 15% RFP Plan identifies excess 2008 NOx reductions of 116.6 tons per day. The 3% contingency, if needed, can be met with these excess NOx reductions.

The 2002 Adjusted-to-2008 Baseline VOC Inventor y for the 7-county area is 114.0 tons per day (see Table 6); a 3% contingency would be 3.4 VOC tons per day:

114.0 × 0.03 = 3.4

Section 5.3 of this 15% RFP Plan identifies excess 2008 VOC reductions of 61.7 tons per day. The 3% contingency, if needed, can be met with these excess VOC reductions.

36 "...EPA will interpret the Act to require States...to in clude sufficient contingency measures...so that, upon implementation of such measures, additional emissions reductions of up to 3 percent of the emissions in the adjusted base year...would be achieved in the year following the year in which the failure has been identified." From section III.A.3.(c) of General Preamble for the Implementation of Title I of the Clean Air Act Amendments of 1990 , 57 FR 13498, April 16, 1992.

239.0 REPORTING REQUIREMENTS

All of the control measures being relied upon for th e success of this 15% RFP SIP are already in place. Georgia Power's compliance with the state rule regulating NOx emissions from large EGU point sources is reflected in the emissions data they report to EPA's CEMS clearinghouse. This
information can be retrieved here: http://camddataandmaps.epa.gov/gdm/i ndex.cfm?fuseaction=emissions.wizard

Compliance with Georgia's Gasoline Marketing Ru le is assured through the Rule's reporting and sampling requirements, and through EPD enforcemen t action if violations occur. Compliance with Georgia's Stage I and Stage II gasoline vapor recovery rules, and it s open burning rule, is assured through EPD enforcement action if viol ations occur. Compliance with Georgia's Enhanced Inspection and Maintenance program is enforced through registration denial.

2410.0 CONCLUSIONS

In the nonattainment area as a whole, the emissi on controls being relied upon for this 15% RFP
Plan were found to be more than sufficient to reduce overall NOx and VOC emissions by the required amounts and also to offset all of the gr owth in emissions projected to occur between 2002 and 2008. As shown in Tables 17 and 18, a lthough projected emissions for 2008 are above the target levels calc ulated for 7-county VOC and 13-c ounty NOx, with VOC reductions from the 13-county area and NOx reductions from th e 7-county area the 15% emissions reductions required in the Atlanta area by 2008 are easily achieved.

Table 17 -- VOC Target Level and Project ed Emissions for the 15% RFP Plan

2008 VOC Emissions (tons/day) 7-County VOC

Target Level Projected 7-County VOC Inventory Tons over 7- County Target Available 13-County VOC Reductions Excess Nonattainment Area VOC Reductions
96.9 109.8 12.9 74.6 61.7

Table 18 -- NOx Target Level and Project ed Emissions for the 15% RFP Plan

2008 NOx Emissions (tons/day) 13-County NOx

Target Level Projected 13-County NOx Inventory Tons over 13- County Target Available 7-County NOx Reductions Excess Nonattainment Area NOx Reductions
441.2 450.7 9.5 126.1 116.6

25