IDEM INDIANA DEPARTMENT OF ENVIRONMENTAL MANAGEMENT

We Protect Hoosiers and Our Environment.

Mitchell E. Daniels Jr. 100 North Senate Avenue

Governor Indianapolis, Indiana 46204

(317) 232-8603

Thomas W. Easterly Toll Free (800) 451-6027

Commissioner www.idem.IN.gov

May 31, 2011

Ms. Susan Hedman

Regional Administrator

U.S. Environmental Protection Agency

Region 5

77 West Jackson Boulevard

Chicago, IL 60604-3950

Dear Ms. Hedman:

Re: Request for Redesignation Petition and

Maintenance Plan Under the Annual

National Ambient Air Quality Standard for

Fine Particles for the Central Indiana

Nonattainment Area

The Indiana Department of Environmental Management (IDEM) submits a

Redesignation Petition and Maintenance Plan for the Central Indiana Nonattainment

Area, which was designated as nonattainment of the annual standard for fine particles on

April 5, 2005. IDEM conducted a public hearing concerning the Redesignation Petition

and Maintenance Plan on May 17, 2011, and the public comment period concluded on

May 19, 2011.

This submittal documents the public review process, including a detailed summary

of, and response to, substantive comments.

The attached document consists of the following:

Redesignation Petition and Maintenance Plan

• A formal request that the Central Indiana Area be redesignated to attainment and

reclassified as maintenance. It contains and meets the requirements set forth in

Section 107 of the Clean Air Act and in United States Environmental Protection

Agency (U.S. EPA) Redesignation Guidance.

• A maintenance year of 2025 is established and 2015 and 2020 are analyzed as

interim years.

• The appendices of the document contain historical air quality trend data, projected

emission inventory data, and thorough documentation of the mobile emissions

analysis.

Recycled Paper (i) An Equal Opportunity Employer Please Recycle 0
Ms. Hedman

Page 2

Motor Vehicle Emissions Budgets

• Contained in the Redesignation Petition is a new Motor Vehicle Emissions Budget

for 2015 and 2025. The Indianapolis Department of Metropolitan Development's

travel demand forecasting model and the U.S. EPA's software program referred to

as MOBILE6.2 were used to determine emissions for the annual fine particle

nonattainment area.

• A conservative margin of safety was applied to the 2015 and 2025 projected

emissions.

• The travel demand model was updated with the best available assumptions.

• Vehicle registration data gathered from the Indiana Bureau of Motor Vehicles were

used to replace the MOBILE6.2 default vehicle age distribution.

Combined with the October 20, 2009 submittal, IDEM requests that U.S. EPA

proceed with review and approval of this submittal. If you have any questions or need

additional information, please contact Scott Deloney, Chief, Air Programs Branch, at

(317) 233-5694.

Sincerely,

I~ (J)~r Keith Baugues

Assistant Commissioner

Office of Air Quality

KB/sad/skr

Enclosure:

Request for Redesignation Petition and Maintenance Plan Under the Annual

National Ambient Air Quality Standard for Fine Particles for the Central Indiana

Nonattainment Area

Cc: John Summerhays, U.S. EPA Region 5 (wi enclosures)

Matt Rau, U.S. EPA Region 5 (wi enclosures)

John Mooney, U.S. EPA Region 5 (no enclosures)

Cheryl Newton, U.S. EPA Region 5 (no enclosures)

Pat Morris, U.S. EPA Region 5 (no enclosures)

Scott Deloney, IDEM (no enclosures)

Christine Pedersen, IDEM (no enclosures)

Sarah Raymond, IDEM (wi enclosures)
 

REQUEST FOR REDESIGNATION AND 

MAINTENANCE PLAN 

UNDER THE ANNUAL NATIONAL 

AMBIENT AIR QUALITY 

STANDARD FOR FINE PARTICLES 

Central Indiana Area

Prepared By: 

The Indiana Department of Environmental Management 

 May 2011
ii 

This page intentionally left blank

 
iii 

TABLE OF CONTENTS 

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

1.1 Background ................................................................................................................................1 

1.2 Geographical Description ..........................................................................................................3 

1.3 Status of Air Quality ..................................................................................................................3 

2.0 REQUIREMENTS FOR REDESIGNATION ......................................................................3

2.1 General .......................................................................................................................................3 

2.2 Fine Particles Monitoring ..........................................................................................................3 

2.3 Emission Inventory ....................................................................................................................4 

2.4 Modeling Demonstration ...........................................................................................................4 

2.5 Controls and Regulations ...........................................................................................................4 

2.6 Corrective Actions for Potential Future Violations of the Fine Particle Standard ....................5 

3.0 FINE PARTICLES MONITORING .....................................................................................5 

3.1 Fine Particles Monitoring Network ...........................................................................................5 

3.2 Ambient Fine Particles Monitoring Data ...................................................................................7

3.3 Quality Assurance ....................................................................................................................10 

3.4 Continued Monitoring ..............................................................................................................10 

4.0 EMISSION INVENTORY ....................................................................................................10

4.1 Emission Trends .......................................................................................................................10 

4.2 Base Year Inventory ................................................................................................................18 

4.3 Emission Projections ................................................................................................................18 

4.4 Demonstration of Maintenance ................................................................................................22 

4.5 Permanent and Enforceable Emission Reductions ..................................................................23 

4.6 Provisions for Future Updates .................................................................................................23 

5.0 TRANSPORTATION CONFORMITY BUDGETS ..........................................................23 

5.1 Onroad Emission Estimates .....................................................................................................23 

5.2 Overview ..................................................................................................................................25 

5.3 Analysis Years .........................................................................................................................25 

5.4 Emission Estimates ..................................................................................................................25 

5.5 Motor Vehicle Emission Budget ..............................................................................................26 

5.6 Commitment to Amend Motor Vehicle Emission Budgets Using Motor Vehicle 

Emission Simulator (MOVES) ...............................................................................................26 
iv 

6.0 CONTROL MEASURES AND REGULATIONS ..............................................................27

6.1 Reasonably Available Control Technology (RACT) ...............................................................27 

6.2 Implementation of Past State Implementation Plan (SIP) Revisions.......................................27 

6.3 Nitrogen Oxides (NOx) Rule ....................................................................................................27 

6.4 Measures Beyond Clean Air Act SIP Requirements ...............................................................28 

6.5 Controls to Remain in Effect ...................................................................................................32 

6.6 New Source Review Provisions ...............................................................................................32 

7.0 MODELING AND METEOROLOGY................................................................................33

7.1 Summary of Modeling Results to Support Rulemakings ........................................................33 

7.2 Lake Michigan Air Directors Consortium (LADCO) Round 5 Speciated Modeled 

Attainment Test Results ...........................................................................................................36 

7.3 LADCO Round 5 Fine Particle Source Apportionment Results .............................................37 

7.4 Summary of Existing Modeling Results ..................................................................................41 

7.5 Meteorological Analysis for Central Indiana ...........................................................................41 

7.6 Surface Air Conditions Present During High Fine Particle Concentration Days ....................41 

7.7 Upper Air Conditions Present During High Fine Particle Concentration Days ......................41 

7.8 Analysis of Atmospheric Conditions During High Fine Particle Concentration Days ...........42 

7.9 Summary of Air Quality Index (AQI) Days in Central Indiana ..............................................42 

7.10 Summary of Meteorological Analysis for Central Indiana ....................................................44 

8.0 CORRECTIVE ACTIONS ...................................................................................................44

8.1 Commitment to Revise Plan ....................................................................................................44 

8.2 Commitment for Contingency Measures .................................................................................44 

8.3 Contingency Measures .............................................................................................................45 

9.0 PUBLIC PARTICIPATION ................................................................................................46

10.0 CONCLUSIONS ..................................................................................................................46

FIGURES

Figure 3.1 Central Indiana Nonattainment Area ..............................................................................6 

Figure 5.1 Central Indiana Metropolitan Planning Organization Jurisdictions .............................24 
v 

CHARTS

Chart 7.1 Regional/Emission Sector Particulate Source Apportionment Technology (PSAT) 

Results by Sector for Marion County at E. Michigan Street Fine Particles (PM2.5) 

Monitor ..........................................................................................................................38 

Chart 7.2 Regional/Pollutant Sector PSAT Results by Contribution for Marion County at 

E. Michigan Street PM2.5 Monitor .................................................................................38 

Chart 7.3 Species Modeled Contributions to W. 18th Street PM2.5 Monitor in Marion 

 County ...........................................................................................................................39 

Chart 7.4 Species Modeled Contributions to Washington Park PM2.5 Monitor in Marion 

 County ..........................................................................................................................39 

Chart 7.5 Species Modeled Contributions to E. 75th Street PM2.5 Monitor in Marion County .....40 

Chart 7.6 Species Modeled Contributions to Mann Road PM2.5 Monitor in Marion County .......40 

Chart 7.7 Species Modeled Contributions to E. Michigan Street PM2.5 Monitor in Marion 

 County ...........................................................................................................................40 

Chart 7.8 Distribution of PM2.5 Concentration Days in Central Indiana on the AQI Levels 

 of Health Concern .........................................................................................................43 

TABLES

Table 1.1 National Ambient Air Quality Standards for Fine Particles ............................................2 

Table 3.1 Monitoring Data for the Central Indiana Area .................................................................7 

Table 4.1 Comparison of 2008 Estimated and 2025 Projected Emission Estimates .....................22 

Table 5.1 Emission Estimates for Onroad Mobile Sources ...........................................................25 

Table 5.2 Motor Vehicle Emission Budgets ..................................................................................26 

Table 6.1 Trends in Electric Generating Unit (EGU) NOx Emissions Statewide in Indiana .........28 

Table 7.1 Clean Air Transport Rule Modeling Results from U.S. EPA - 2010 .............................33 

Table 7.2 Clean Air Transport Rule Modeling Results from U.S. EPA – 2010 ............................35 

Table 7.3 LADCO Round 6 Modeling Results for Annual PM2.5 – Without the Clean Air 

 Interstate Rule Emission Reductions .............................................................................35 

Table 7.4 LADCO Round 5 SMAT Modeling Results for Central Indiana ..................................37 

Table 7.5 Ranking and Percentage of Highest Number of Days at AQI Levels of Health 

 Concern .........................................................................................................................43 
vi 

GRAPHS

Graph 3.1 Design Values for the Central Indiana Area for Fine Particles, 2006 

through 2010 ....................................................................................................................8 

Graph 3.2 Central Indiana Annual Fine Particles Trends, 2006 through 2010 ................................9 

Graph 4.1 Central Indiana Area NOx Point Source Emission Trends, 2002, 2006, and 2008 .......11 

Graph 4.2 Central Indiana Area Sulfur Dioxide (SO2) Point Source Emission Trends, 

2002, 2006, and 2008 ....................................................................................................11 

Graph 4.3 Central Indiana Area Direct PM2.5 Point Source Emission Trends, 2002, 2006, 

 and 2008 ........................................................................................................................12 

Graph 4.4 NOx Emission Trends, All Sources in the Central Indiana Area, 2002, 2006, 

 and 2008 ........................................................................................................................13 

Graph 4.5 SO2 Emission Trends, All Sources in the Central Indiana Area, 2002, 2006, 

 and 2008 ........................................................................................................................13 

Graph 4.6 Direct PM2.5 Emission Trends, All Sources in the Central Indiana Area, 2002, 

 2006, and 2008 ..............................................................................................................14 

Graph 4.7 NOx Emissions from EGUs, Central Indiana Area, 1999 to 2009 ................................15 

Graph 4.8 SO2 Emissions from EGUs, Central Indiana Area, 1999 to 2009 ................................16 

Graph 4.9 Indiana Statewide NOx Emissions from EGUs, 1999 to 2009 ......................................17 

Graph 4.10 Indiana Statewide SO2 Emissions from EGUs, 1999 to 2009 ....................................17 

Graph 4.11 Comparison of 2005 and 2008 Estimated and 2015, 2020, and 2025 Projected 

NOx Emissions for the Central Indiana Area ................................................................20 

Graph 4.12 Comparison of 2005 and 2008 Estimated and 2015, 2020, and 2025 Projected 

SO2 Emissions for the Central Indiana Area .................................................................20 

Graph 4.13 Comparison of 2005 and 2008 Estimated and 2015, 2020, and 2025 Projected 

Direct PM2.5 Emissions for the Central Indiana Area ...................................................21 

Graph 4.14 Comparison of 2005 and 2008 Estimated and 2015, 2020, and 2025 Projected 

NOx, SO2, and Direct PM2.5 Emissions Trends for the Central Indiana Area ..............21 

Graph 7.1 PM2.5 Design Value Trends for the Central Indiana Area: 2000 - 2010 .......................34 

Graph 7.2 LADCO Modeling Results for Central Indiana PM2.5 Monitors for 2012 and 

 2018 ...............................................................................................................................36 
vii 

APPENDICES

A Air Quality System (AQS) and Indiana Department of Environmental Management 

(IDEM) Monitor Data Values for the Central Indiana Area (2000-2010) 

B NOx, SO2, and Direct PM2.5 Point Source Emissions (2002, 2006, and 2008) for Central 

Indiana Area 

C NOx, SO2, and Direct PM2.5 Emission Trends, All Sources, (2002, 2006, and 2008) for 

Central Indiana Area. 

D NOx and SO2 Emissions from EGUs, Central Indiana Area 

E 2006 and 2008 Base Years Emission Inventories and 2015, 2020, and 2025 Projected 

Emission Inventories for NOx, SO2, and Direct PM2.5 for Central Indiana Area 

F Mobile Source Input and Output Calculation Files for Central Indiana Area 

G IDEM – Area Source Inventory Standard Operating Procedure 

H Modeling Summary 

I LADCO Emission Estimates Technical Support Document 

J LADCO Round 5 Modeling Technical Support Document (Round 5 Photochemical 

Modeling Based on “Base M” Emissions Inventory, revised version of “Base K”) 

K Public Participation Process Documents 
viii 

This page intentionally left blank
1

REQUEST FOR REDESIGNATION AND MAINTENANCE PLAN 

UNDER THE ANNUAL NATIONAL AMBIENT AIR 

QUALITY STANDARD FOR FINE PARTICLES 

CENTRAL INDIANA AREA 

1.0 INTRODUCTION

 

This document supports Indiana’s request that Hamilton, Hendricks, Johnson, Marion, and 

Morgan counties (herein referred to as the “Central Indiana Area”), be redesignated from 

nonattainment to attainment of the 1997 annual standard for fine particles. All monitors for fine 

particles in the Central Indiana Area have recorded three years of quality assured ambient air 

quality monitoring data for the years 2008 through 2010, demonstrating attainment with the 

annual standard for fine particles, therefore, the Central Indiana Area is eligible for 

redesignation. 

Section 107 of the Clean Air Act (CAA) establishes specific requirements to be met in order for 

an area to be considered for redesignation, including: 

(a) A determination that the area has attained the annual standard for fine particles. 

(b) A State Implementation Plan (SIP) for the area under Section 110(k) is fully 

approved. 

(c) A determination that the improvement in air quality is due to permanent and 

enforceable reductions in emissions resulting from implementation of the SIP and 

other federal requirements.

(d) A maintenance plan under Section 175A is fully approved. 

(e) A determination that all Section 110 and Part D requirements have been met. 

A maintenance plan provides for the continued attainment of the air quality standard by an area 

for a period of ten years after the United States Environmental Protection Agency (U.S. EPA) 

has formally redesignated the area to attainment. The plan also provides assurances that even if 

there is a subsequent exceedance of the air quality standard, then measures in the maintenance 

plan will prevent any future occurrences through contingency measures that would be triggered. 

This document addresses each of these requirements, and provides additional information to 

support continued compliance with the annual standard for fine particles. 

1.1 Background

The CAA requires states with areas designated nonattainment of the applicable National 

Ambient Air Quality Standard (NAAQS) for fine particles to develop SIPs to expeditiously 

attain and maintain the standard. In 1997, U.S. EPA set daily and annual air quality standards 

for fine particles (PM2.5), as shown in Table 1.1. The terms “fine particles” and PM2.5” are used 

synonymously throughout this document. The PM2.5 standards were legally challenged and 

upheld by the U.S. Supreme Court in February of 2001. In 1999, the Indiana Department of 
2

Environmental Management (IDEM) began monitoring for fine particle concentrations. The 

U.S. EPA designated areas in Indiana under the annual fine particles standard on December 17, 

2004, as attainment, nonattainment or unclassifiable, with an effective date of April 5, 2005. 

Table 1.1 

National Ambient Air Quality Standards for Fine Particles 

Annual 24-Hour 

1997 PM2.5 Standards 

15 μg/m3

Annual arithmetic mean, 

averaged over three years 

65 μg/m3

24-hour average, 98th percentile, 

averaged over three years 

2006 PM2.5 Standards 

15 μg/m3

Annual arithmetic mean, 

averaged over three years 

35 μg/m3

24-hour average, 98th percentile, 

averaged over three years 

Note: The Central Indiana Area meets the 1997 and 2006 24-hour NAAQS for fine particles. Since this 

area is solely designated nonattainment under the 1997 annual standard for fine particles, this document 

only addresses the annual standard. 

On December 17, 2004, based on 2001 through 2003 monitoring data, U.S. EPA designated the 

Central Indiana Area as nonattainment of the annual standard for fine particles. The Central 

Indiana Area was subject to Section 172 of the CAA, including the development of a plan to 

reduce nitrogen oxides (NOx), sulfur dioxide (SO2), and direct PM2.5 particle emissions and a 

demonstration that the area will meet the annual standard for fine particles by April 5, 2010. In 

order to satisfy these requirements, Indiana submitted a redesignation petition and maintenance 

plan to U.S. EPA on October 20, 2009, demonstrating that the Central Indiana Area had met the 

NAAQS for fine particles by April 5, 2010, with an ample margin of safety. The Central Indiana 

Area monitors have continued to meet the annual NAAQS for fine particles since the end of 

2007. 

There were no fine particle monitors in the Central Indiana Area that violated the 1997 24-hour 

standard for fine particles and none that currently violate the 2006 24-hour standard for fine 

particles. As a result, the Central Indiana Area was designated nonattainment for fine particles 

solely under the 1997 annual standard. Therefore, this document pertains only to the 1997 

annual standard for fine particles. 

 The Central Indiana nonattainment area for fine particles, as defined in Section 1.2, has not 

previously been subject to nonattainment area rulemakings for fine particles. However, Marion 

County was subject to nonattainment area rulemakings under the 1-hour ozone standard. The 1-

hour ozone standard was revoked on June 15, 2005. Boone, Hamilton, Hancock, Hendricks, 

Johnson, Madison, Marion, Morgan, and Shelby counties in Central Indiana had also been 

subject to nonattainment area rulemakings under the 8-hour ozone standard and all counties in 

Central Indiana were redesignated to attainment and classified as maintenance under the 8-hour 

ozone standard on October 19, 2007. 

 
3

 1.2 Geographical Description

 The Central Indiana nonattainment area for annual fine particles consists of Hamilton, 

Hendricks, Johnson, Marion, and Morgan counties. The Central Indiana Area includes cities 

such as Beech Grove, Carmel, Franklin, Greenwood, Indianapolis, Lawrence, Martinsville, and 

Noblesville and such towns as Avon, Brownsburg, Fishers, Mooresville, Plainfield, and 

Speedway. This area is depicted in Figure 3.1. 

 

 IDEM is the agency responsible for assuring the nonattainment area for fine particles complies 

with the CAA requirements and is responsible for the entire Central Indiana Area. IDEM has 

worked cooperatively with U.S. EPA Region V to address attainment planning issues. 

 1.3 Status of Air Quality

Monitoring data for fine particles for the three years, 2008 through 2010, demonstrates that air 

quality has met the annual NAAQS for fine particles in the Central Indiana Area. This fact, 

accompanied by the permanent and enforceable reductions in emission levels discussed in 

Section 4.0, justifies a redesignation to attainment for the Central Indian area based on Section 

107(d)(3)(E) of the CAA. 

2.0 REQUIREMENTS FOR REDESIGNATION

2.1 General

Section 110 and Part D of the CAA list a number of requirements that must be met by 

nonattainment areas prior to consideration for redesignation to attainment. In addition, U.S. EPA 

has published detailed guidance in a document entitled “Procedures for Processing Requests to 

Redesignate Areas to Attainment”, issued September 4, 1992, to Regional Air Directors. This 

document is hereafter referred to as “Redesignation Guidance”. This Request for Redesignation 

and Maintenance Plan is based on the Redesignation Guidance, supplemented with additional 

guidance received from staff of the Attainment Planning and Maintenance Section of U.S. EPA 

Region V. The specific requirements for redesignation are listed below. 

2.2 Fine Particles Monitoring 

1) A demonstration that the annual standard for fine particles, as published in 40 

Code of Federal Regulations (CFR) 50.13, has been attained. Fine particle 

monitoring data must show that violations of the annual ambient standard are no 

longer occurring. 

 

2) Ambient monitoring data quality assured in accordance with 40 CFR 58.15, 

recorded in the U.S. EPA Air Quality System (AQS) database, and available for 

public view. 
4

3) A showing that the three-year average of annual values, based on data from all 

monitoring sites in the area or its affected downwind environs, do not exceed 15.0 

micrograms per cubic meter (μg/m3

). This showing must rely on three complete, 

consecutive calendar years of quality assured data. 

4) A commitment that, once redesignated, the state will continue to operate an 

appropriate monitoring network to verify the area is in compliance (maintenance) 

with the standard. 

2.3 Emission Inventory 

1) A comprehensive emission inventory of the precursors of fine particles (direct 

PM2.5, NOx and SO2) completed for the base year (2008 in this case). 

2) A projection of the emission inventory to a year at least ten years following 

redesignation. 

3) A demonstration that the projected level of emissions is sufficient to maintain the 

annual standard for fine particles. 

4) A demonstration that improvement in air quality between the year violations 

occurred and the year attainment was achieved is based on permanent and 

enforceable emission reductions and not on temporary adverse economic 

conditions or unusually favorable meteorology. 

5) Provisions for future updates of the inventory to enable tracking of the emission 

levels, including emission inventory statements from emission sources. 

2.4 Modeling Demonstration 

While no modeling is required for redesignating nonattainment areas, IDEM has evaluated the 

results of federal control-case modeling to demonstrate that compliance with the standard will be 

maintained. 

2.5 Controls and Regulations 

1) A U.S. EPA approved SIP control strategy that includes Reasonably Available 

Control Technology (RACT) requirements for existing stationary sources covered 

by Control Technology Guidelines (CTG) and non-CTG RACT for all major 

sources. 

2) Evidence that control measures required in past SIP revisions have been fully 

implemented. 

 

3) Acceptable provisions to provide for new source review. 
5

4) Assurances that existing controls will remain in effect after redesignation, unless 

the state demonstrates through photochemical modeling that the standard can be 

maintained without one or more controls. 

5) If appropriate, a commitment to adopt a requirement that all transportation plans 

conform with, and are consistent with, the SIP. 

2.6 Corrective Actions for Potential Future Violations of the Fine Particle Standard

1) A commitment to submit a revised plan eight years after redesignation. 

2) A commitment to expeditiously enact and implement additional contingency 

control measures in response to exceeding specified predetermined levels 

(triggers) or in the event that future violations of the ambient standard occur. 

3) A list of potential contingency measures that would be implemented in such an 

event. 

4) A list of NOx, SO2, and direct PM2.5 sources potentially subject to future controls. 

3.0 FINE PARTICLES MONITORING

3.1 Fine Particles Monitoring Network

There are currently three Federal Reference Method monitors measuring fine particle 

concentrations in this nonattainment area. The monitors are located in Marion County at 

Washington Park, West 18th Street, and East Michigan Street. The monitors are operated by 

IDEM’s Office of Air Quality (OAQ). A listing of the monitor readings from 2008 through 

2010, are shown in Table 3.1 and Appendix A and was retrieved from U.S. EPA’s AQS 

database. The locations of the monitoring sites for this nonattainment area are shown in Figure 

3.1. 

IDEM also operates two fine particle monitors in Marion County (West Street and School 21) 

that are considered source oriented monitors. While the source oriented monitors are not used to 

determine attainment with the annual standard for fine particles, the monitoring locations and 

data are included as supporting material. Two monitors (Mann Road and East 75th Street, both in 

Marion County) in the Central Indiana Area were discontinued at the end of 2007. 
6

Figure 3.1 

Central Indiana Nonattainment Area 
7

3.2 Ambient Fine Particles Monitoring Data

The following information summarizes U.S. EPA's "Guideline on Data Handling Conventions 

for the PM NAAQS," U.S. EPA-454/R-99-008, April 1999. Three complete years of fine 

particle monitoring data are required to demonstrate attainment at a monitoring site. The annual 

ambient air quality standard for fine particles is met at an ambient air quality monitoring site 

when the three-year average of the annual average of fine particle concentrations is less than or 

equal to 15.0 μg/m3. When this occurs, the site is said to be in attainment. While calculating 

design values, three significant digits must be carried in the computations, with final values 

rounded to the nearest 0.1 μg/m3. Decimals 0.05 or greater are rounded up, and those less than 

0.05 are rounded down, so that 15.049 μg/m3 is the largest concentration that is less than or equal 

to 15.0 μg/m3

. Values at or below 15.0 μg/m3meet the standard. Values equal to or greater than 

15.1 μg/m3 exceed the standard. 

Data handling procedures are applied on an individual basis at each monitor in the area. An 

individual site’s three-year average of the annual average fine particles concentration is also 

called the site’s design value. An area is in compliance with the annual NAAQS for fine 

particles only if all monitoring sites meet the NAAQS. The air quality design value for the area 

is the highest design value among all sites in the area. Table 3.1 outlines the annual fine particle 

values by site and the 2008 through 2010 design values for the three active fine particle 

monitoring sites in the Central Indiana nonattainment area. The nearby Anderson monitor is 

included for supporting material. Appendix A contains the complete monitoring data summary 

from 2000 to 2010 for all of the Central Indiana monitors which includes the three active fine 

particle monitoring sites, the Anderson monitor, the two source oriented monitoring sites, and the 

two discontinued monitoring sites in the Central Indiana Area. 

Table 3.1 

Monitoring Data for the Central Indiana Area 

(Annual Average and 2008-2010 Design Values) 

SITE ID COUNTY SITE NAME YEAR Annual Average 

(μg/m3

) 

2008-2010 Design 

Value (μg/m3) 

180970078 Marion IndianapolisWashington Park 

2008 13.02 

2009 12.11 12.7 

2010 12.86 

180970081 Marion Indianapolis-W 18th

Street 

2008 13.75 

2009 12.96 13.6 

2010 14.03 

180970083 Marion Indianapolis-E. 

Michigan Street 

2008 13.17 

2009 12.40 13.2 

2010 13.91 
8

Graph 3.1 visually demonstrates the 2006 through 2010 design values for the Central Indiana 

Area.

Graph 3.1

Design Values for the Central Indiana Area, 2006 through 2010 

Red line represents the annual standard for fine particles of 15 μg/m3. 

Note: The Indianapolis Mann Road and E. 75th Street monitors were discontinued December 31, 2007. 

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

Indianapolis‐Mann Road

Indianapolis‐

Washington Park

Indianapolis‐E. 75th

Street

Indianapolis‐W 18th

Street

Indianapolis‐E.

Michigan Street

2006‐2008

2007‐2009

2008‐2010

μg/m3
9

Graph 3.2 

Central Indiana Annual Fine Particles Trends, 2006 through 2010 

Red line represents the annual standard for fine particles of 15 μg/m3. 

Note: The Indianapolis Mann Road and E. 75th Street monitors were discontinued December 31, 2007. 

The design values for the Central Indiana nonattainment area demonstrate that the annual 

NAAQS for fine particles has been attained. Appendix A contains the complete fine particles 

monitoring data summary for the years 2000 through 2010. 

Graph 3.1 shows the trend in design values, while Graph 3.2 shows the trend for annual fine 

particles. A comprehensive list of the design values for the three monitoring sites over the 2000 

through 2010 period is outlined in Appendix A. The area's design values have recently trended 

downward, as emissions have declined due to programs such as the Acid Rain program and 

cleaner automobiles and fuels, both regionally and locally. U.S. EPA’s rule to control nitrogen 

oxides from specific source categories (40 CFR Parts 51, 72, 75 and 96, published on October 

17, 1998 and referred to as the “NOx SIP Call”) has significantly reduced emissions from large 

electric generating units (EGUs), industrial boilers, and cement kilns. Indiana's NOx SIP Call 

Rule was adopted into the Indiana Administrative Code (IAC) on June 6, 2001 at 326 IAC 10-3 

and 326 ICA 10-4. The elevated fine particle values for 2005 are considered an abnormal 

occurrence. An analysis of meteorological conditions and monitoring values is included in 

Section 7.0 and supports the conclusion that attainment of the standard as of 2010 is not the 

result of unusually favorable meteorological conditions. It is expected that this downward trend 

11.00

12.00

13.00

14.00

15.00

16.00

17.00

2006 2007 2008 2009 2010

Indianapolis‐Mann Road Indianapolis‐Washington Park

Indianapolis‐E. 75th Street Indianapolis‐W 18th Street

Indianapolis‐E. Michigan Street

μg/m3

Year
10

will persist as the above programs continue and U.S. EPA’s proposed Clean Air Transport Rule 

is implemented. 

3.3 Quality Assurance

IDEM has quality assured all data shown in Appendix A in accordance with 40 CFR 58.10 and

recorded the data in the AQS database and, thus, the data is available to the public. 

3.4 Continued Monitoring

Indiana commits to continue monitoring fine particle concentrations at the sites indicated in 

Table 3.1 and Appendix A. IDEM will consult with U.S. EPA Region V staff prior to making 

changes to the existing monitoring network through the annual network review should changes 

become necessary in the future. IDEM will continue to quality assure the Indiana monitoring 

data to meet the requirements of 40 CFR 58. IDEM will enter all data into AQS on a timely 

basis in accordance with federal guidelines. 

4.0 EMISSION INVENTORY 

U.S. EPA’s Redesignation Guidance and Implementation Rules require the submittal of a 

comprehensive inventory of precursor emissions for fine particles (NOx, SO2, and direct PM2.5) 

representative of the year when the area achieves attainment of the annual NAAQS for fine 

particles (base year). IDEM is using 2008 as the base year. Consistent with the federal 

implementation rule for fine particles, IDEM and U.S. EPA do not consider volatile organic 

compounds (VOCs) or ammonia (NH3) to be significant contributors to fine particles. IDEM 

must also demonstrate that the improvement in air quality between the year that violations 

occurred and the year that attainment was achieved is based on permanent and enforceable 

emission reductions. Other requirements related to the emission inventory include: a projection 

of the emission inventory to a year at least ten years following redesignation; a demonstration 

that the projected level of emissions is sufficient to maintain the annual standard for fine 

particles; and, a commitment to provide future updates of the inventory to enable tracking of 

emission levels during the ten year maintenance period. The following subsections address each 

of these requirements. 

4.1 Emission Trends

Point Sources

The point source data are obtained from Indiana's emissions reporting program and are based on 

county point source totals. The Central Indiana Area had a 34.21 percent (%) reduction in NOx 

point source emissions from 2002 to 2008. As Graph 4.7 illustrates, Central Indiana NOx

emissions from electric generating units have decreased substantially during this time period as 

well. The Central Indiana Area had a 44.59% reduction in SO2 point source emissions from 

2002 to 2008. The large decrease in SO2 point source emissions from 2006 to 2008 is due to the 

shutdown of the Citizens Gas and Coke plant in Indianapolis. A moderate increase in direct 
11

PM2.5 point source emissions from 2002 to 2008 is noted. However, this increase in direct PM2.5 

emissions is due to the fact that most companies did not submit their direct PM2.5 emissions data 

in 2002, but did submit direct PM2.5 data in the 2005/2006 emissions inventory, from which the 

2008 inventory is extrapolated. Graphs 4.1, 4.2, and 4.3 demonstrate the trend in point source 

emissions of NOx, SO2, and direct PM2.5 for the Central Indiana Area that generally correspond 

to the years of monitored values used in this redesignation petition. Graphs and data tables of 

emissions for the point source category can be found in Appendix B. 

Graph 4.1 

Central Indiana Area NOx Point Source Emission Trends, 2002, 2006, and 2008 

Graph 4.2 

Central Indiana Area SO2 Point Source Emission Trends, 2002, 2006, and 2008 

‐

5,000

10,000

15,000

20,000

25,000

2002 2006 2008

Tons per Year

Nitrogen Oxides Year

‐

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

2002 2006 2008

Tons per Year

Year Sulfur Dioxide
12

Graph 4.3 

Central Indiana Area Direct PM2.5 Point Source Emission Trends, 2002, 2006, and 2008 

All Anthropogenic Sources

Periodic inventories, which include emissions from all sectors (mobile, area, nonroad, and point 

source), were prepared for 2002, 2005/2006, and 2008. The 2006 and 2008 data were 

extrapolated from the 2005 emission inventory. Graphs 4.4, 4.5, and 4.6 show the trend in 

anthropogenic source emissions for the Central Indiana Area. Regional NOx emission reductions 

affect fine particle levels in the Central Indiana Area far more so than NOx emission reductions 

within the nonattainment area itself. These emission trends roughly follow the years of 

monitored trends discussed in Section 3.0. There is a downward trend in NOx emissions from 

2002 to 2006 and a further decrease through 2008. The decrease in NOx can be largely attributed 

to the impact of the NOx SIP Call. There is a general downward trend in SO2 emissions from 

2002 to 2008, as well. As noted previously, there is an overall increase in direct PM2.5 

anthropogenic emissions. Graphs and data tables of emissions from each source category are 

available in Appendix C. 

‐

500

1,000

1,500

2,000

2,500

3,000

2002 2006 2008

Tons per Year

Direct Fine Particles Year
13

Graph 4.4 

NOx Emission Trends, All Sources in the Central Indiana Area, 2002, 2006, and 2008 

Graph 4.5 

SO2 Emission Trends, All Sources in the Central Indiana Area, 2002, 2006, and 2008

‐

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

2002 2006 2008

Tons per Year

Nitrogen Oxides Year

‐

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

90,000

2002 2006 2008

Tons per Year

Year Sulfur Dioxide
14

Graph 4.6 

Direct PM2.5 Emission Trends, All Sources in Central Indiana Area, 2002, 2006, and 2008 

EGU Sources

Graphs 4.7 and 4.8 show both NOx and SO2 emissions are decreasing substantially in response to 

national programs affecting all EGUs, such as the Acid Rain program and the NOx SIP Call. 

Other sectors of the inventory also impact the formation of fine particles, but large regional 

sources, such as EGUs, have a substantial impact on the formation of fine particles. 

The data were taken from U.S. EPA's Clean Air Markets database located at 

http://www.epa.gov/airmarkets. Data are available sooner for these units than other point 

sources in the inventory because of the NOx SIP Call budget and trading requirements. 

As part of the NOx SIP Call, the states were required to adopt into their rules a budget for all 

large EGUs. Indiana’s budget is referenced in 326 IAC 10-4. The budget represents a statewide 

cap on NOx emissions. Although each unit is allocated emissions based upon historic heat input, 

utilities can meet this budget by over-controlling certain units or purchasing credits from the 

market to account for overages at other units. To summarize, NOx emissions have dramatically 

decreased over the years represented on these graphs. 

These emissions, capped by the state rule, are expected to remain near these levels throughout 

the maintenance period covered by this request. The state cap for the NOx SIP Call remained in 

place through 2008, at which time the Clean Air Interstate Rule (CAIR) program superseded it. 

‐

1,000

2,000

3,000

4,000

5,000

6,000

2002 2006 2008

Tons per Year

Year Direct Fine Particles
15

CAIR, issued in March 2005, adopted by the Indiana Air Pollution Control Board on November 

1, 2006, and implemented beginning in 2010, will continue to reduce regional EGU NOx 

emissions statewide by approximately another 17% by 2015 and 57% for EGU SO2 emissions by 

2015. The D.C. Circuit court’s vacatur of CAIR in July of 2008 and subsequent remand without 

vacatur of CAIR in December of 2008, directs U.S. EPA to revise the CAIR rule in the future. 

The proposed Clean Air Transport Rule (CAIR’s replacement rule) will result in similar or 

greater emission reductions than assumed within the current emission inventories, once it is 

implemented. 

Graph 4.7

NOx Emissions from EGUs, Central Indiana Area, 1999 to 2009 

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

Nitrogen Oxides

Tons per Year

Year
16

Graph 4.8

SO2 Emissions from EGUs, Central Indiana Area, 1999 to 2009 

Although there are minor fluctuations in emissions over time, as shown in Graphs 4.7 and 4.8, 

there are moderate reductions to date. Indiana does expect to see significant reductions in SO2

emissions from CAIR and Best Available Retrofit Technology (BART), once implemented. 

Additional NOx control technologies have been installed on various emission units at the 

Indianapolis Power & Light Company (IPL)-Harding Street Generating Station located in 

Marion County as well as the IPL-Eagle Valley Generating Station, located in Morgan County, 

since the 2001-2003 monitoring period. These control technologies include selective noncatalytic reduction, selective catalytic reduction, neural net controls, low NOx burners, and 

separated overfire air. The SO2 data from 2008 reflects the installation of a flue gas 

desulphurization system at the IPL-Harding Street Generating Station that became operational in 

2007. As IPL indicates, many control technologies have been installed voluntarily and are not 

required to be operated. Most of the major sources within the area are subject to the NOx SIP 

Call, CAIR or RACT requirements. Appendix B shows detailed emissions for the point source 

emissions, and Appendix D shows detailed emissions for the EGUs. 

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

Sulfur Dioxide

Tons per Year
17

Graph 4.9 

Indiana Statewide NOx Emissions from EGUs, 1999 to 2009 

Graph 4.10 

Indiana Statewide SO2 Emissions from EGUs, 1999 to 2009 

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

400,000

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

Nitrogen Oxides

Tons per Year

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

900,000

1,000,000

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

Sulfur Dioxide

Tons per Year
18

4.2 Base Year Inventory

IDEM prepared a comprehensive inventory for the Central Indiana Area, including area, mobile, 

nonroad, and point sources for direct PM2.5, NOx and SO2 for 2005/2006 and 2008 (the years with 

the most complete emissions inventory available at this time). The 2008 emission inventory 

represents a base year for maintenance purposes. The 2007 implementation rule for the annual 

fine particle standard states that NOx, SO2, and direct PM2.5 are the regulated precursors of fine 

particles. Ammonia and VOCs are not required to be addressed unless the state or U.S. EPA 

make a technical demonstration that emissions of these pollutants from sources in the state 

significantly contribute to PM2.5 concentrations in a given nonattainment area. U.S. EPA and 

IDEM have not determined ammonia or VOCs are significant contributors to fine particles 

formation in Indiana. IDEM’s 2008 base year inventory was developed as follows: 

 Area sources were extrapolated from the Indiana 2005 periodic inventory submitted to 

U.S. EPA. 

 Mobile source emissions were calculated from MOBILE6.2 model-produced emission 

factors and data extracted from the region’s travel-demand model. These emissions were 

then interpolated as needed to determine 2008 base year values. 

 Point source information was compiled from IDEM’s emissions inventory database and 

U.S. EPA’s Clean Air Markets acid rain database. 

 Biogenic emissions are not specifically included in these summaries, but are included in 

the photochemical modeling results presented in Section 7.0. 

 Nonroad emissions were extrapolated from the 2005 National Emissions Inventory 

(NEI). To address concerns about the accuracy of some of the categories in U.S. EPA’s 

nonroad emissions model, Lake Michigan Air Directors Consortium (LADCO) 

contracted with two companies to review the base data and make recommendations. One 

of the contractors also estimated emissions for two nonroad categories not included in 

U.S. EPA's nonroad model. Emissions were estimated for commercial marine vessels 

and railroads. The recreational motorboat population and spatial surrogates (used to 

assign emissions to each) were significantly updated. The populations for the 

construction equipment category were also reviewed and updated based upon surveys 

completed in the Midwest and the temporal allocation for agricultural sources was also 

updated. A new nonroad estimation model was provided by U.S. EPA for the 2005 

analysis. 

Appendix C contains data tables and graphs of these emissions. 

4.3 Emission Projections

In consultation with the U.S. EPA and other stakeholders, IDEM selected the year 2025 as the 

maintenance year for this redesignation request. This document contains projected emission 

inventories for 2015, 2020, and 2025 for the Central Indiana Area. These emission projections 

were prepared by IDEM, with assistance from LADCO and the Indianapolis Metropolitan 

Planning Organization. The projected emission inventories for 2020 and 2025 were extrapolated 

from 2018 estimates developed by LADCO. 
19

The detailed 2015, 2020, and 2025 emission inventory for the Central Indiana Area can be found 

in Appendix E. Emission trends are an important gauge for continued compliance with the 

annual standard for fine particles. Therefore, IDEM performed an initial comparison of the 

inventories for the base year of 2005/2006, secondary validation year of 2008, interim years of 

2015 and 2020, and maintenance year of 2025 for the Central Indiana Area. 

The 2005/2006 LADCO modeling inventory was used as the basis for estimated emissions for 

the years 2008, 2015, 2020, and 2025, using LADCO’s growth factors, for all sectors except 

point sources (electrical generating units and non-electric generating units). Point source 

emissions for 2005/2006 and 2008 were compiled from Indiana’s emission inventory database. 

The 2006 base year and 2008 secondary validation emissions were extrapolated from the 2005 

emission inventory. The 2015 interim year emissions were interpolated based on the 2009 and 

2018 LADCO modeling inventory, using LADCO’s growth factors, for all sectors. The 2020 

interim year emissions and the 2025 maintenance year emissions were extrapolated from the 

2009 and 2018 LADCO modeling inventory. 

Graphs 4.11, 4.12, and 4.13 visually compare 2008 NOx, SO2, and direct PM2.5 county total 

estimated emissions with the 2015, 2020, and 2025 projected emissions for the Central Indiana 

Area. Mobile source emission inventories are further described in Section 5.0. In addition to 

LADCO’s estimates, point source emissions were projected based upon the statewide EGU NOx

budgets from the Indiana NOx rule. It should be noted that EGU emission estimates for 2015, 

2020, and 2025 were projected utilizing the Department of Energy Information’s Annual Energy 

Outlook Supplemental tables for the year 2018. These tables were generated for the reference 

case of the Annual Energy Outlook 2007 using the National Energy Modeling System. Graphs 

and data tables of emissions from the EGU source category can be found in Appendix D. 
20

Graph 4.11 

Comparison of 2005 and 2008 Estimated and 2015, 2020, and 2025 Projected NOx

Emissions for the Central Indiana Area 

Graph 4.12 

 Comparison of 2005 and 2008 Estimated and 2015, 2020, and 2025 Projected SO2

Emissions for the Central Indiana Area

‐

10,000

20,000

30,000

40,000

50,000

60,000

2006 2008 2015 2020 2025

Tons per Year

Nitrogen Oxides Year

‐

10,000

20,000

30,000

40,000

50,000

60,000

70,000

2006 2008 2015 2020 2025

Tons per Year

Year Sulfur Dioxide
21

Graph 4.13 

Comparison of 2005 and 2008 Estimated and 2015, 2020, and 2025 Projected Direct PM2.5

Emissions for the Central Indiana Area 

Graph 4.14 

Comparison of 2005 and 2008 Estimated and 2015, 2020, and 2025 Projected NOx, SO2, 

and Direct PM2.5 Emission Trends for the Central Indiana Area 

‐

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

5,000

2006 2008 2015 2020 2025

Tons per Year

Direct Fine Particles Year

‐

10,000

20,000

30,000

40,000

50,000

60,000

70,000

2006 2008 2015 2020 2025

Tons per Year

Nitrogen Oxides Sulfur Dioxide Direct Fine Particles
22

NOx emissions within the Central Indiana Area are projected to decline by 44.07% between 2008 

and 2025. Emission reduction benefits from U.S. EPA rules covering the NOx SIP Call, Tier 2 

Motor Vehicle Emission Standards and Gasoline Sulfur Control Requirements, Heavy-Duty 

Highway Engine Rule, and the Nonroad Diesel Engine Rule are factored into the changes. 

Additionally, due to implementation of the NOx SIP Call across the eastern United States, NOx

and fine particle levels entering the Central Indiana Area will also be decreased. SO2 emissions 

within the Central Indiana Area are projected to decline by 25.98% between 2008 and 2025. 

Direct PM2.5 emissions from 2008 to 2025 are projected to decline by 3.11% within the Central 

Indiana Area. The 2015, 2020, and 2025 emission projections assume no additional controls will 

be installed. This approach over-predicts future year emissions as it is reasonable to assume a 

significant number of facilities will need to install additional controls to comply with CAIR or 

the proposed Clean Air Transport Rule. 

Table 4.1 

Comparison of 2008 Estimated and 2025 Projected Emission Estimates Central Indiana 

Area (Tons Per Year) 

2008 2025 Change % Change 

NOx 50,777.76 28,399.04 -22,378.72 44.07% Decrease 

SO2 43,502.68 32,201.49 -11,301.19 25.98% Decrease 

Direct PM2.5 4,103.99 3,976.18 -127.81 3.11% Decrease 

4.4 Demonstration of Maintenance

Quality-assured ambient air quality data from all the monitoring sites indicate that air quality in 

the Central Indiana Area met the annual standard for fine particles for the three-year period 

ending in 2010. U.S. EPA’s Redesignation Guidance states, “A state may generally demonstrate 

maintenance of the NAAQS by either showing that future emissions of a pollutant or its 

precursors will not exceed the level of the attainment inventory, or by modeling to show that the 

future mix of sources and emission rates will not cause a violation of the NAAQS.” (Page 9) 

Section 3.0 of this document shows that the Central Indiana Area has in fact measured attainment 

for fine particles for the three consecutive periods ending in 2008, 2009 and 2010. Additionally, 

emission projections outlined in Section 4.0 of this document clearly illustrate that regional NOx, 

SO2, and direct PM2.5 emissions in the area will continue to decline leading to local reductions 

between 2008 (base year) and 2025 (maintenance plan horizon). Section 7.0 further discusses 

the implications of these emission trends and provides an analysis to support these conclusions. 

In Indiana, major point sources in all counties are required to submit air emissions information 

once every three years, or annually, if the SO2 or NOx potential to emit is greater than 2,500 tons 

per year in accordance with the Emission Reporting Rule, 326 IAC 2-6. IDEM prepares a new 

periodic inventory for all precursor emission sectors every three years. These precursor emission 

inventories will be prepared for 2011, 2014 and 2017, as necessary, to comply with the inventory 

reporting requirements established in the CAA. Emissions information will be compared to the 

2008 base year and the 2025 projected maintenance year inventories to assess emission trends, as 

necessary, to assure continued compliance with the annual standard for fine particles. 
23

4.5 Permanent and Enforceable Emission Reductions

Permanent and enforceable reductions of NOx and SO2 have contributed to the attainment of the 

annual standard for fine particles. Some of these reductions were due to the implementation of 

the NOx SIP Call rule, and some were due to the application of tighter federal standards on motor 

vehicles and fuels. 

Section 6.0 identifies the emission control measures specific to the Central Indiana Area, as well 

as the implementation status of each measure. 

4.6 Provisions for Future Updates 

 

As required by Section 175A(b) of the CAA, Indiana commits to submit to the Administrator, 

eight years after redesignation, an additional revision of this SIP. The revision will contain 

Indiana's plan for maintaining the national primary fine particles air quality standard for ten years 

beyond the first ten-year period after redesignation. 

5.0 TRANSPORTATION CONFORMITY BUDGETS 

U.S. EPA requirements outlined in 40 CFR 93.118(e)(4) stipulate that mobile source emission 

budgets for direct PM2.5 and NOx be established as part of a SIP. The motor vehicle emission 

budgets (MVEBs) are necessary to demonstrate conformance of transportation plans and 

improvement programs with the SIP. 

5.1 Onroad Emission Estimates

The Indianapolis Department of Metropolitan Development (DMD), the Madison County 

Council of Governments (MCCOG), and the Columbus Area Metropolitan Planning 

Organization are the Metropolitan Planning Organizations (MPOs), whose planning areas 

intersect the five county Central Indiana Area. In addition, significant portions of the 

nonattainment area are not under the jurisdiction of any MPO. These planning areas in relation 

to the counties in the PM2.5 nonattainment area are illustrated in Figure 5.1. 

An interagency consultation group consisting of representatives from the three MPOs, the 

Indiana Department of Transportation, IDEM, the Federal Highway Administration, and local 

transit and environmental quality providers jointly determine regional significance. Primary 

responsibility for modeling emissions falls under the purview of DMD, which runs the 

MOBILE6.2 model to arrive at emission rates, and its regional travel model to develop estimates 

of vehicle miles traveled (VMT) for all areas, except for the MCCOG planning area, which 

administers its own travel model. DMD then compiles all results into a regional emissions 

analysis, which all MPOs then adopt following a public involvement period. 
24

Figure 5.1 

Central Indiana Metropolitan Planning Organization (MPO) Jurisdictions

These models simulate the traffic in the area and are used to predict what the traffic would be 

like in future years given growth expectations. The models are used mostly to identify where 

travel capacity will be needed and to determine the infrastructure requirements necessary to meet 

that need. They are also used to support the calculation of mobile source emissions. The travel 

demand forecast model is used to predict the total daily VMT and the U.S. EPA software 

program, MOBILE6.2, is used to calculate per mile emissions. The product of these two outputs, 

once combined, is the estimated total amount of pollution emitted by the onroad vehicles for the 

area analyzed. 
25

5.2 Overview 

Broadly described, MOBILE6.2 is used to determine “emission factors”, which are the average 

emissions per mile (grams/mile) for fine particles and fine particle precursors, including direct 

PM2.5, NOx and SO2. There are numerous variables that can affect the emission factors. The 

vehicle-fleet (vehicles on the road) age and the vehicle types have a major effect on the emission 

factors. The facility-type on which the vehicles are traveling (MOBILE6.2 facility-types are 

Freeway, Arterial, Local, and Ramp) and the vehicle speeds also affect the emission factor 

values. Meteorological factors such as air temperature and humidity affect emission factors as 

well. These data are estimated using the best available data to create emission factors for fine 

particle precursors including direct PM2.5, NOx and SO2. After emission factors are determined, 

they must be multiplied by the VMT to determine the quantity of vehicle-related emissions. This 

information is derived from the travel demand model. 

It should be noted that each year analyzed will have different emission factors, volumes, speeds, 

and likely results in additional modeling. MOBILE6.2 input and output files are found in 

Appendix F. 

5.3 Analysis Years

The travel demand model contains road networks that are time specific. The Central Indiana 

MPOs have modeled the years 2002, 2010, 2015, and 2025. Information, including emissions, 

has been interpolated from 2002 and 2010 for the years 2005, 2006, and 2008 and from 2015 and 

2025 for the year 2020. This Redesignation Petition provides emission inventory estimates for 

2002, 2005, 2006, 2008, 2015, 2020, and 2025 to meet the requirements specified by the CAA 

and U.S. EPA. The emission estimates outlined in Section 4.0 of this document reference the 

mobile source emissions data contained in Table 5.1. 

5.4 Emission Estimates 

Table 5.1 outlines onroad emission estimates for the entire nonattainment area for the years 

2002, 2005, 2006, 2008, 2015, 2020, and 2025. 

Table 5.1 - Emission Estimates for Onroad Mobile Sources 

 2002 2005 2006 2008 2015 2020 2025 

VMT 

(thousand 

miles/day) 

 

52,979.53 

 

49,540.45 

 

48,394.10 

 

46,101.38 

 

46,614.09 

 

49,355.27 

 

52,096.44 

PM2.5

(tons/year) 670.50 423.11 416.63 403.67 289.67 275.11 260.54 

NOx

(tons/year) 38,059.50 23,354.20 22,734.38 21,494.74 12,259.66 9,752.70 7,245.74 
26

5.5 Motor Vehicle Emission Budget 

Table 5.2 contains the motor vehicle emissions budget for the entire nonattainment area for the 

years 2015 and 2025. These MVEBs are intended to be direct replacements of those provided in 

Indiana’s previous submittal. 

Table 5.2 – Motor Vehicle Emission Budgets (Tons Per Year) 

Year 2015 2025 

PM2.5 353.40 317.86 

NOx 14,956.79 8,839.80 

Consistent with the federal implementation rule for fine particles, Indiana does not consider 

mobile source SO2 to be a significant contributor to fine particles for this nonattainment area, as 

mobile source SO2 constitutes less than 1.2% of the area’s total anthropogenic emissions. 

These budgets include emission estimates calculated for 2015 and 2025. The emission estimates 

are derived from the MPO’s travel demand models and MOBILE6.2, as described above. 

Through the interagency consultation process, it was determined that an interim budget year of 

2015, in addition to the horizon year budget of 2025, would be appropriate. A reasonable margin 

of safety has been applied to the 2015 and 2025 budgets in the amount of 22% for both PM2.5 and 

NOx. Margins of safety are used to accommodate the wide array of assumptions that are factored 

into the calculation process. Since assumptions change over time, it is necessary to have a 

margin of safety that will accommodate the impact of refined assumptions in the process. 

The rule at 40 CFR 93.101 defines safety margin as the amount by which the total projected 

emissions from all sources of a given pollutant are less than the total emissions that would satisfy 

the applicable requirement for reasonable further progress, attainment, or maintenance. When 

compared to the overall safety margin as defined by 40 CFR 93.101, it is evident this allocation 

to mobile sources is significantly below the total safety margin for all sources in the Central 

Indiana Area as detailed in Table 4.1. 

5.6 Commitment to Amend Motor Vehicle Emission Budgets Using Motor Vehicle Emission 

Simulator (MOVES)

On March 2, 2010, U.S. EPA published a Notice of Availability for the Motor Vehicle Emission 

Simulator (MOVES) model. IDEM is committed to submitting a revision to the MOBILE6.2 

developed MVEBs using the MOVES model as soon as possible and well in advance of the 

March 2, 2012, expiration of the transportation conformity “grace period.” IDEM recognizes 

that U.S. EPA will allow the MOBILE6.2 budgets to be replaced through an adequacy notice in 

place of a full publication to the Federal Register. 

 

All methodologies, latest planning assumptions, margins of safety, and MOVES model 

commitments were determined appropriate through the interagency consultation 

process. 
27

6.0 CONTROL MEASURES AND REGULATIONS

This section provides specific information on the control measures that have been or will be 

implemented in the Central Indiana Area, including CAA requirements and additional state or 

local measures implemented beyond CAA requirements. 

6.1 Reasonably Available Control Technology (RACT)

 As required by Section 172 of the CAA, in the mid-1990s, Indiana promulgated rules requiring 

RACT for emissions of VOCs. There were no specific rules required by the CAA, such as 

RACT for existing sources, beyond statewide rules. Statewide RACT rules have applied to all 

new sources locating in Indiana since that time. The Indiana rules are found in 326 IAC 8. The 

following is a listing of applicable rules: 

 326 IAC 8-1-6 BACT for Non-Specific Sources 

326 IAC 8-2 Surface Coating Emission Limitations 

326 IAC 8-3 Solvent Degreasing Operations 

326 IAC 8-4 Petroleum Sources 

326 IAC 8-5 Miscellaneous Operation 

326 IAC 8-6 Organic Solvent Emission Limitations 

Since the Central Indiana Area attained the annual standard for fine particles prior to an 

Attainment SIP or RACT SIP being due, and since the Implementation Rule for fine particles 

stipulates that states are only required to draft and implement RACT rules for the precursor 

emission reductions necessary to attain the standard, no further RACT rules are required for this 

area. These Indiana rules are CAA requirements already in the SIP and provide secondary 

benefits for PM2.5. 

6.2 Implementation of Past SIP Revisions

The area was only recently designated nonattainment for the annual standard for fine particles in 

2003 and the area has now attained the standard well in advance of its attainment deadline of 

2010. As a result, Indiana is no longer required to develop and submit an Attainment SIP or 

RACT SIP for this area under the annual NAAQS for fine particles. 

6.3 Nitrogen Oxides Rule

The U.S. EPA NOx SIP Call required twenty-two states to adopt rules that would result in 

significant emission reductions from large EGUs, industrial boilers, and cement kilns in the 

eastern United States. The Indiana rule was adopted in 2001. Beginning in 2004, this rule 

accounts for a reduction of approximately 31% of all NOx emissions statewide compared to 

previous uncontrolled years. 

Twenty-one other states have also adopted these rules. The result is that significant reductions 

have occurred regionally and within the nonattainment area because of the number of affected 

units within the region. From Graphs 4.7, it can be seen that emissions covered by this program 
28

have been trending downward since 1999. Table 6.1, compiled from data taken from the U.S. 

EPA Clean Air Markets web site, quantifies the gradual NOx reductions that have occurred in 

Indiana as a result of Title IV (Acid Rain) of the CAA and the NOx SIP Call Rule. The NOx SIP 

Call cap stayed in place through 2008, at which time the caps in the CAIR program superseded 

it. Since CAIR is a regional cap and trade program, it cannot be predicted at this time what 

effect this will have on EGU units located in the nonattainment area or other upwind counties. 

Further, U.S. EPA published Phase II of the NOx SIP Call that established a budget for large 

(emissions of greater than 1 ton per day) stationary internal combustion engines. In Indiana, the 

rule decreases emissions statewide from natural gas compressor stations by 4,263 tons during the 

ozone season (April through September). The Indiana Phase II NOx SIP Call Rule became 

effective February 26, 2006, and implementation began in 2007. 

Table 6.1 

Trends in EGU NOx Emissions Statewide in Indiana 

Year NOx Emissions (tons/year) 

1999 347,216.5 

2000 334,522.1 

2001 315,419.7 

2002 281,146.1 

2003 260,980.0 

2004 224,311.3 

2005 207,981.6 

2006 202,728.0 

2007 196,553.1 

2008 196,134.5 

2009 110,968.9 

Budget 2009-2014 108,935 

Budget 2015 and later 90,779 

6.4 Measures Beyond Clean Air Act SIP Requirements

Reductions in fine particles precursor emissions have occurred, or are anticipated to occur, as a 

result of local and federal programs. These additional control measures include those listed in 

this section. 

Tier 2 Vehicle Standards1

Federal Tier 2 motor vehicle standards require all passenger vehicles in a manufacturer’s fleet, 

including light-duty trucks and sport utility vehicles (SUVs), to meet an average standard of 0.07 

grams of NOx per mile. Implementation began in 2004 and was completed in 2007. The Tier 2 

 

1 http://www.epa.gov/fedrgstr/EPA-AIR/2000/February/Day-10/a19a.htm
29

standards also cover passenger vehicles over 8,500 pounds gross vehicle weight rating (larger 

pickup trucks and SUVs), which are not covered by the current Tier 1 standards. 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 the 

program. The Tier 2 standards also reduced the sulfur content of gasoline to 30 parts per million 

(ppm) beginning in January 2006. Most gasoline sold in Indiana prior to January 2006 had a 

sulfur content of about 500 ppm. Sulfur occurs naturally in gasoline, but interferes with the 

operation of catalytic converters on vehicles resulting in higher NOx emissions. Lower sulfur 

gasoline is necessary to achieve the Tier 2 vehicle emission standards. 

Heavy-Duty Gasoline and Diesel Highway Vehicle Standards2

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

and diesel highway vehicles took effect in 2004. A second phase of standards and testing 

procedures, that began in 2007, reduced fine particles from heavy-duty highway engines and also 

reduced highway diesel fuel sulfur content to 15 ppm since the sulfur can damage emission 

control devices. The total program is expected to achieve a 90% reduction in direct PM2.5 

emissions and a 95% reduction in NOx emissions for these new engines using low sulfur diesel, 

compared to existing engines using higher sulfur content diesel. There will also be SO2

reductions from these rules. U.S. EPA has not quantified the expected reductions. 

Large Nonroad Diesel Engine Standards3

In May 2004, 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 approximately 3,400 ppm sulfur. This rule 

limited nonroad diesel sulfur content to 500 ppm by 2006, with a further reduction to 15 ppm by 

2010. The combined engine and fuel rules will reduce NOx and PM emissions from large 

nonroad diesel engines by over 90%, compared to current nonroad engines using higher sulfur 

content diesel. 

Nonroad Spark-Ignition Engines and Recreational Engine Standards

This new standard, effective in July 2003, regulates NOx, VOCs, and carbon monoxide (CO) for 

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

sold in the United States and imported after the standards went into effect. The standard applies 

to large spark-ignition engines (forklifts and airport ground service equipment), recreational 

vehicles (off-highway motorcycles and all-terrain vehicles), and recreational marine diesel 

engines. The regulation varies based upon the type of engine and vehicle. 

The emissions from large spark-ignition engines contribute to ozone formation and ambient CO 

and PM2.5 levels in urban areas. Tier 1 of this standard was implemented in 2004 and Tier 2 

started in 2007. Like the large spark-ignition engines, emissions from recreational vehicles 

 

2 http://www.epa.gov/fedrgstr/EPA-AIR/1997/October/Day-21/a27494.htm 3 http://www.epa.gov/fedrgstr/EPA-AIR/1998/October/Day-23/a24836.htm
30

contribute to ozone and fine particles formation and ambient CO and PM2.5 levels. For Model 

Year 2006 off-highway motorcycles and all-terrain vehicles, at least 50% of a manufacture’s 

fleet was required to meet the new exhaust emissions standard and 100% of the fleet was 

required to meet the standards in 2007. Recreational marine diesel engines over 37 kilowatts are 

used in yachts, cruisers, and other types of pleasure craft. Emissions from recreational marine 

engines contribute to ozone formation and PM levels, especially surrounding marinas. 

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

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

CO emissions are expected by 2020. 

Reciprocating Internal Combustion Engine Standards4

 

This new standard, effective in May 2010, regulates emissions of air toxics emissions from 

existing diesel powered stationary reciprocating internal combustion engines that meet specific 

site rating, age and size criteria. These engines are typically used at industrial facilities (e.g. 

power, chemical, and manufacturing plants) to generate electricity for compressors and pumps 

and to produce electricity to pump water for flood and fire control during emergencies. 

The standard applies to stationary diesel engines: (1) used at area sources of air toxics and 

constructed or reconstructed before June 12, 2006; (2) used at major sources of air toxics, having 

a site rating of less than or equal to 500 horsepower, and constructed or reconstructed before 

June 12, 2006; and (3) used at major sources of air toxics for non-emergency purposes, having a 

site rating of greater than 500 horsepower, and constructed or reconstructed before December 19, 

2002. 

Operators of existing engines will be required to: (1) install emissions control equipment that 

would limit air toxics up to 70% for stationary non-emergency engines with a site rating greater 

than 300 horsepower; (2) perform emission tests to demonstrate engine performance and 

compliance with rule requirements; and (3) burn ultra-low sulfur fuel in stationary nonemergency engines with a site rating greater than 300 horsepower. 

When all of the reciprocating internal combustion engine standards are fully implemented in 

2013, U.S. EPA estimates that emissions from these engines will reduce air toxics by 

approximately 1,000 tons per year (tpy), PM2.5 by 2,800 tpy, CO by 14,000 tpy, and VOC by 

27,000 tpy. 

Category 3 Marine Diesel Engine Standards5

This new standard, effective in June 2010, promulgates more stringent exhaust emission 

standards for new large marine diesel engines with per-cylinder displacement at or above 30 

liters (commonly referred to as Category 3 compression-ignition marine engines) as part of a 

coordinated strategy to address emissions from all ships that affect U.S. air quality. These 

emission standards are equivalent to those adopted in the amendments to Annex VI to the 

 

4 http://www.epa.gov/ttn/atw/rice/fr03mr10.pdf 5 http://www.regulations.gov/search/Regs/home.html#documentDetail?R=0900006480ae43a6 
31

International Convention for the Prevention of Pollution from Ships (MARPOL Annex VI). The 

emission standards apply in two stages—near-term standards for newly built engines will apply 

beginning in 2011; long-term standards requiring an 80% reduction in NOx emissions will begin 

in 2016. 

U.S. EPA is adopting changes to the diesel fuel program to allow for the production and sale of 

diesel fuel with up to 1,000 ppm sulfur for use in Category 3 marine vessels. The regulations 

generally forbid production and sale of fuels with more than 1,000 ppm sulfur for use in most 

U.S. waters, unless operators achieve equivalent emission reductions in other ways. 

U.S. EPA is also adopting provisions to apply some emission and fuel standards to foreignflagged and in-use vessels that are covered by MARPOL Annex VI. 

When this strategy is fully implemented in 2030, U.S. EPA estimates that NOx and PM2.5 

emissions in the U.S. will be reduced by approximately 1.2 million tpy and 143,000 tpy, 

respectively. 

Clean Air Interstate Rule (CAIR)

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

Particulate Matter and Ozone (Clean Air Interstate Rule); Revisions to Acid Rain Program; 

Revisions to the NOx SIP Call”; Final Rule (70 FR 25162). This rule established the requirement 

for states to adopt rules limiting the emissions of NOx and SO2 and provided a model rule for the 

states to use in developing their rules to meet federal requirements. The purpose of CAIR was to 

reduce interstate transport of precursors to fine particles and ozone. 

CAIR applied to: (1) any stationary, fossil-fuel-fired boiler or stationary, fossil-fuel-fired 

combustion turbine, a generator with a nameplate capacity of more than 25 megawatt electrical 

(MWe) producing electricity for sale; and (2) a unit that qualifies as a cogeneration unit during 

the 12-month period starting on the date that the unit first produces electricity and continues to 

qualify as a cogeneration unit, a cogeneration unit serving at any time a generator with a 

nameplate capacity of more than 25 MWe and supplying in any calendar year more than onethird of the unit’s potential electric output capacity or 219,000 megawatt hours (MWh), 

whichever is greater, to any utility power distribution system for sale. 

This rule provides annual state caps for NOx and SO2 in two phases, with the Phase I caps for 

NOx and SO2 starting in 2009 and 2010, respectively. Phase II caps become effective in 2015. 

U.S. EPA is allowing the caps to be met through a cap and trade program if a state chooses to 

participate in the program. 

In response to U.S. EPA’s rulemaking, IDEM adopted a state rule in 2006 based on the model 

federal rule. IDEM’s rule includes annual and seasonal NOx trading programs, and an annual 

SO2 trading program. This rule requires compliance effective January 1, 2009. 

SO2 emissions from power plants in the 28 eastern states and the District of Columbia covered 

by CAIR will be cut by 4.3 million tons by 2009 and reduced by an additional 5.4 million tons in 
32

2015. NOx emissions will be cut by 1.7 million tons by 2009 and reduced by an additional 1.3 

million tons in 2015. The D.C. Circuit court’s vacatur of CAIR in July of 2008 and subsequent 

remand without vacatur of CAIR in December of 2008 directs U.S. EPA to revise or replace 

CAIR in order to properly address the deficiencies outlined by the court. 

Since the court’s opinion made it clear that CAIR is deficient and must be revised or replaced, 

the program cannot be defined as permanent and enforceable for SIP purposes. On July 6, 2010, 

U.S. EPA proposed the Clean Air Transport Rule to replace CAIR. The Clean Air Transport 

Rule will result in even further benefits above and beyond CAIR than what is assumed within the 

emission inventories and modeling. 

Together, these rules will substantially reduce local and regional sources of fine particle 

precursors. The modeling analyses discussed in Section 7.0 include these rules and show the 

reductions in annual fine particle concentrations expected to result from the implementation of 

these rules. 

6.5 Controls to Remain in Effect

IDEM commits to maintain the control measures listed above after redesignation, or submit to 

U.S. EPA, as a SIP revision, any changes to its rules or emission limits applicable to SO2, NOx,

or direct PM2.5 sources as required for maintenance of the annual standard for fine particles in the 

Central Indiana Area. 

Indiana, through IDEM’s Office of Air Quality and its Compliance and Enforcement Branch, has 

the legal authority and necessary resources to actively enforce any violations of its rules or 

permit provisions. After redesignation, it intends to continue enforcing all rules that relate to the 

emission of fine particles and fine particle precursors in the Central Indiana Area. 

6.6 New Source Review Provisions

Indiana has a long standing and fully implemented New Source Review (NSR) program that is 

outlined in rule at 326 IAC 2. The rule includes provisions for the Prevention of Significant 

Deterioration (PSD) permitting program in 326 IAC 2-2 and the emissions offset rule in 326 IAC 

2-3. Indiana's PSD program was conditionally approved on March 3, 2003 (68 FR 9892) and 

received final approval on May 20, 2004 (69 FR 29071) by U.S. EPA as part of the SIP. 

Any emission unit that is not listed in the 2005 emission inventory, or for which credit through 

the shutdown or curtailment of operations was taken in demonstrating attainment, will not be 

allowed to construct, reopen, modify, or reconstruct without meeting all applicable permit rule 

requirements. The review process will be identical to that used for new sources. Once the area 

is redesignated, OAQ will implement NSR through the PSD program, which requires an air 

quality analysis to evaluate whether the new source will threaten the NAAQS. 
33

7.0 MODELING AND METEOROLOGY 

Although U.S. EPA’s Redesignation Guidance does not require modeling for nonattainment 

areas seeking redesignation, extensive modeling has been performed for the Central Indiana Area 

to determine the effect of national emission control strategies on fine particle levels. These 

modeling analyses determined that the Central Indiana Area, including Hamilton, Hendricks, 

Johnson, Marion, and Morgan counties are significantly impacted by regional transport of fine 

particles and its precursors, and that regional SO2 and NOx reductions are an effective way to 

attain the annual standard for fine particles in this area. Future year modeled annual fine particle 

concentrations are expected to be reduced by 2% to 10% from baseline design values. Examples 

of these modeling analyses are described in this section and can also be found in Appendix H. 

7.1 Summary of Modeling Results to Support Rulemakings

U.S. EPA Modeling for Clean Air Transport Rule 20106

U.S. EPA performed modeling to support the emission reductions associated with the proposed 

Clean Air Transport Rule. U.S. EPA used the Comprehensive Air Quality Model with Extension 

(CAMx, version 5), applied to the 2005 meteorology, as processed by the Mesoscale Model 

(MM5), version 3.7.4. Emissions input into CAMx included SO2, NOx, VOCs, NH3, and direct 

PM2.5 for 2005. The modeling was based on the annual fine particle design values calculated 

from 2003 through 2005, 2004 through 2006, and 2005 through 2007. Future year modeling was 

conducted, which included the Central Indiana Area, and the future year design values for 2012 

and 2014 were evaluated for attainment of the annual NAAQS for fine particles of 15 μg/m3, as 

shown in Table 7.1. Fine particle concentrations are accounted for by modeling both the base 

future year emissions and then the emission reductions associated with the Clean Air Transport 

Rule. U.S. EPA found model performance met suggested benchmark performance goals within 

or close to the ranges found in other comparable modeling applications. 

Table 7.1 

Clean Air Transport Rule Modeling Results from U.S. EPA – 2010 

County Monitor ID 

Design Value

2003-2007 

(μg/m3

)

Future 

Design 

Value 

2012 Base 

(μg/m3

)

Future Design 

Value 

2014 Base 

(μg/m3

)

Madison 180950009 13.96 13.80 13.35 

Marion 180970042 14.24 14.26 13.78 

Marion 180970078 15.26 15.18 14.69 

Marion 180970079 14.71 14.61 14.12 

Marion 180970081 16.05 15.93 15.43 

Marion 180970083 15.90 15.77 15.27 

 

6 http://www.epa.gov/airquality/transport/pdfs/TR_AQModeling_TSD.pdf 
34

Modeling results show that the base future year modeling with emission reductions from the 

Clean Air Transport Rule will account for a 0.2 μg/m3

 decrease in concentrations for 2012, as 

well as a 0.5 to 0.6 μg/m3 decrease in concentrations for 2014 in Marion and Madison counties 

within the Central Indiana Area. 

While results of U.S. EPA’s Clean Air Transport Rule modeling indicate modeled concentrations 

above the standard using base case emissions at the Washington Park, West 18th Street, and East 

Michigan Street PM2.5 monitoring sites, it should be noted that the base year design value used 

by U.S. EPA was taken from 2003 through 2007 and is higher than current 2006 through 2010 

design values in the area. Graph 7.1 shows the downward trend of the design values from 2000 

through 2010 for the PM2.5 monitors in the Central Indiana Area. In fact, all design values for 

the Central Indiana Area are below the annual NAAQS for fine particles. 

Graph 7.1 

PM2.5 Design Value Trends for the Central Indiana Area: 2000 – 2010 

The decrease of the 2003-2007 design value compared to the 2006-2010 design value at the 

Washington Park PM2.5 monitor is 1.74 μg/m3

 with all the area’s PM2.5 monitor design values 

decreasing from 1.73 μg/m3

 to 2.10 μg/m3. Therefore, U.S. EPA’s Clean Air Transport Rule 

modeling, using current 2006 through 2010 design values, shows all modeled concentrations 

well below the annual fine particle standard of 15.0 μg/m3

, as seen in Table 7.2. 

12.0

13.0

14.0

15.0

16.0

17.0

00‐04 01‐05 02‐06 03‐07 04‐08 05‐09 06‐10

Concentrations(ug/m3)

Design Value Years

Anderson Mann Road Washington Park E. 75th St.

W. 18th St. E. Michigan St. Annual Standard
35

Table 7.2 

Clean Air Transport Rule Modeling Results from U.S. EPA – 2010 

(using 2006-2010 design values) 

County Monitor ID 

Design Value

2006-2010 

(μg/m3

)

Future 

Design 

Value 

2012 Base 

(μg/m3

)

Future Design 

Value 

2014 Base 

(μg/m3

)

Madison 180950009 12.23 12.09 11.70 

Marion 180970042 a N/A N/A 

Marion 180970078 13.52 13.45 13.02 

Marion 180970079 a N/A N/A 

Marion 180970081 14.18 14.07 13.63 

Marion 180970083 13.80 13.69 13.26 a Site was discontinued in 2007 

N/A Not available

Results of the U.S. EPA’s Clean Air Transport Rule modeling show that all Central Indiana 

counties would attain the annual fine particle NAAQS in 2012 with modeled impacts reduced by 

1%, and will remain below 15 μg/m3

. With further reductions projected in the Clean Air 

Transport Rule for 2014, all design values decrease by 3% to 4% and the area will continue to 

attain the annual NAAQS for fine particles. 

LADCO Modeling for Clean Air Interstate Rule (CAIR) 

LADCO conducted modeling to determine the impact of CAIR in the Midwest. LADCO’s 

modeling used the CAMx model applied to the year 2005 meteorology, as processed by the 

MM5. Emissions input into CAMx included SO2, NOx, VOCs, NH3, and direct PM2.5 for 2005. 

The modeling was based on 2003 through 2007 design values. Future year modeling for 2012 

and 2018 was conducted and the future year design values were determined without the emission 

reductions associated with CAIR (Round 6), as shown in Table 7.3. The Clean Air Transport 

Rule is expected to provide reductions above and beyond CAIR.

Table 7.3 

LADCO Round 6 Modeling Results for Annual PM2.5 – Without the Clean Air Interstate 

Rule Emission Reductions

(Using 2003 – 2007 Design Values) 

Monitor ID 

Monitor 

Name County 

Design 

Value 

2003-2007 

(μg/m3

)

Base-case 

2012 

(μg/m3) 

Base-case 

2018 

(μg/m3) 

180950009 Anderson Madison 14.0 12.9 12.6 

180970042 Mann Road Marion 14.2 13.2 12.9 

180970078 Washington Park Marion 15.3 14.2 13.9 

180970079 E. 75th St. Marion 14.7 13.6 13.2 

180970081 W. 18th St. Marion 16.1 14.9 14.6 

180970083 E. Michigan St. Marion 15.9 14.8 14.5 
36

Results of the LADCO Round 6 modeling show that the Central Indiana Area will attain the 

annual NAAQS for fine particles by 2012. As shown in Table 7.3, future year modeled annual 

fine particle concentrations for 2012 will be 7% to 8% lower than baseline annual fine particle 

design values, and 9% to 10% lower in 2018 and will continue to decrease thereafter. 

A graphical representation is shown in Graph 7.2. The Mann Road and E. 75th Street monitors 

were shut down at the end of 2007. However, at the time the modeling was conducted, both 

monitors were still in operation and therefore are included in this analysis. 

Graph 7.2 

LADCO Modeling Results for Central Indiana PM2.5 Monitors for 2012 and 2018 

7.2 LADCO Round 5 Speciated Modeled Attainment Test Results

The Speciated Modeled Attainment Test (SMAT) is the attainment test for annual fine particles. 

To determine the future year annual fine particle concentrations, speciated data is calculated. 

The different species that were modeled and are associated with fine particles include sulfates, 

nitrates, organic carbon, elemental carbon, ammonium, particle bound water, “other” primary 

inorganic fine particles, and passively collected mass. The SMAT results from LADCO’s Round 

5 modeling are listed below. Round 5 modeled the emission reductions associated with CAIR, 

so the results reflect the impacts from CAIR. Percent ranges of the model results from the five 

fine particle monitors in Central Indiana were broken down into the speciated constituents of fine 

particle emissions. The percent change from the observed speciated data in 2005 to the future 

year modeled results are listed in Table 7.4. While these modeling results are outdated, this 

12.0

13.0

14.0

15.0

16.0

17.0

18.0

2005 2012 2018

PM2.5 Concentrations (ug/m3)

Modeled Year

Anderson Mann Road Washington Park E. 75th St.

W. 18th St. E. Michigan St. Annual Standard
37

weight of evidence demonstration shows the reduction potential from national emission control 

measures for the PM2.5 species in Central Indiana. An updated analysis will be conducted at a 

later time, using more current emissions and meteorological data and for a relevant future year 

projection. 

Table 7.4 

LADCO Round 5 SMAT Modeling Results for Central Indiana 

(Percent decrease from observed to modeled concentrations) 

Species of PM2.5 2009 

Sulfates 23% - 26% 

Nitrates 0% - 6% 

Organic Carbon 0% - 3% 

Elemental Carbon 17% 

Ammonium 16% - 19% 

Particle Bound Water 19% - 24% 

The results demonstrate that sulfate, ammonium, elemental carbon, and particle bound water 

concentration decreases are projected to be at least 16% in 2009. Lesser nitrate reductions are 

projected to occur, up to 6%, with organic carbon reductions up to 3%. LADCO modeling 

shows good performance for sulfates and elemental carbon predicted baseline concentrations, 

slight over-prediction for nitrate concentrations, and under-predictions of organic carbon 

concentrations. Overall, model performance is adequate for SIP planning and gives a good idea 

of the effects of emission reductions from national emission control measures on the Central 

Indiana Area. 

7.3 LADCO Round 5 Particulate Source Apportionment Results

Particulate Source Apportionment (PSAT) modeling was conducted by LADCO. The results of 

the PSAT Round 5 modeling show the regional contributions by emission sectors on each 

monitor that was modeled. Chart 7.1 displays the PSAT modeling results for the E. Michigan 

Street fine particles monitor in Marion County. Indiana was the biggest regional contributor to 

the E. Michigan Street fine particles monitor. Illinois, Ohio, and the Visibility Improvement 

State and Tribal Association of the Southeast (VISTAS) Regional Planning Organization 

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

Virginia and West Virginia and the Eastern Band of the Cherokee Indians) also contributed. 

The PSAT Round 5 modeling results indicate the majority of Indiana’s emission sector 

contributions to fine particle concentrations come from EGUs, ammonium emission sources, 

mobile, off-road (including marine, aircraft and railroad), area, and non-EGU sources. These 

results are considered to be representative of the entire Central Indiana Area as EGU, 

ammonium, and non-EGU emissions impact the entire area. 
38

Chart 7.1 

Regional/Emission Sector PSAT Results by Sector for Marion County at E. Michigan 

Street PM2.5 Monitor 

Chart 7.2 displays the modeled pollutant contributions on the E. Michigan Street fine particles 

monitor. The PSAT modeling results show the majority of Indiana’s pollutant contributions 

come from ammonium, nitrate, sulfate, elemental carbon, primary fine particles and organic 

carbon. Pollutant contributions from other regions consist mainly of sulfates and nitrates. 

Chart 7.2 

Regional/Pollutant PSAT Results by Contribution for Marion County at E. Michigan 

Street PM2.5 Monitor 
39

The following pie charts depict the contributions by species to fine particle concentrations at the 

Central Indiana Area monitors. The pie charts include both the observed 2005 contributions and 

2009 modeled contributions for each monitor. Since the monitors are in close proximity to each 

other, results are fairly similar in the distribution of species concentrations among the monitors. 

Charts 7.3 through 7.7 cover the fine particle monitors in the Central Indiana Area that are used 

to determine compliance with the annual NAAQS for fine particles. 

The speciation listed in the pie charts include SO4 – sulfate mass, NO3 – nitrate mass, OC – 

organic carbon mass, EC – elemental carbon mass, Soil – crustal material mass, NH4 – 

ammonium mass, PBW – particles bound water mass, and BLAN – passively collected mass. 

Chart 7.3 

Modeled Contributions by Species to W. 18th Street PM2.5 Monitor in Marion County 

 (Base Year Modeled Concentrations = 15.6 μg/m3) (Future Year Modeled Concentrations =13.2 μg/m3) 

 

Chart 7.4 

Modeled Contributions by Species to Washington Park PM2.5 Monitor in Marion County 

(Base Year Modeled Concentrations = 14.7 μg/m3) (Future Year Concentrations =12.6 μg/m3) 

 

2005 Modeled Contributions at W. 18th St. PM2.5 Monitor

so4

33%

no3

10%

oc

22%

ec

4%

soil

3%

nh4

14%

pbw

11%

blan

3%

so4

no3

oc

ec

soil

nh4

pbw

blan

2009 Modeled Contributions at W. 18th St. PM2.5 Monitor

so4

27%

no3

12%

oc

26%

ec

4%

soil

4%

nh4

13%

pbw

10%

blan

4%

so4

no3

oc

ec

soil

nh4

pbw

blan

2005 Modeled Contributions at Washington Park PM2.5 Monitor

so4

32%

no3

11%

oc

22%

ec

4%

soil

3%

nh4

14%

pbw

11%

blan

3%

so4

no3

oc

ec

soil

nh4

pbw

blan

2009 Modeled Contributions at Washington Park PM2.5 Monitor

so4

28%

no3

12%

oc

25%

ec

4%

soil

4%

nh4

13%

pbw

10%

blan

4%

so4

no3

oc

ec

soil

nh4

pbw

blan
40

Chart 7.5

Modeled Contributions by Species to E. 75th Street PM2.5 Monitor in Marion County 

(Base Year Modeled Concentrations = 14.2 μg/m3) (Future Year Modeled Concentrations =12.3 μg/m3) 

 

Chart 7.6 

Modeled Contributions by Species to Mann Road PM2.5 Monitor in Marion County 

(Base Year Modeled Concentrations = 13.7 μg/m3) (Future Year Modeled Concentrations =11.9 μg/m3) 

 

Chart 7.7 

Modeled Contributions by Species to E. Michigan Street PM2.5 Monitor in Marion County 

(Base Year Modeled Concentrations = 15.4 μg/m3) (Future Year Modeled Concentrations =13.2 μg/m3) 

 

2005 Modeled Contributions at E. 75th St. PM2.5 Monitor

so4

31%

no3

11%

oc

23%

ec

4%

soil

3%

nh4

13%

pbw

11%

blan

4%

so4

no3

oc

ec

soil

nh4

pbw

blan

2009 Modeled Contributions at E. 75th St. PM2.5 Monitor

so4

28%

no3

12%

oc

25%

ec

4%

soil

4%

nh4

13%

pbw

10%

blan

4%

so4

no3

oc

ec

soil

nh4

pbw

blan

2005 Modeled Contributions to Mann Road PM2.5 Monitor

so4

32%

no3

10%

oc

22%

ec

4%

soil

3%

nh4

14%

pbw

11%

blan

4%

so4

no3

oc

ec

soil

nh4

pbw

blan

2009 Modeled Contributions to Mann Road PM2.5 Monitor

so4

28%

no3

12%

oc

25%

ec

4%

soil

4%

nh4

13%

pbw

10%

blan

4%

so4

no3

oc

ec

soil

nh4

pbw

blan

2005 Modeled Contributions at E. Michigan St. PM2.5 Monitor

so4

32%

no3

11%

oc

23%

ec

4%

soil

3%

nh4

14%

pbw

10%

blan

3%

so4

no3

oc

ec

soil

nh4

pbw

blan

2009 Modeled Contributions at E. Michigan St. PM2.5 Monitor

so4

27%

no3

12%

oc

26%

ec

4%

soil

4%

nh4

13%

pbw

10%

blan

4%

so4

no3

oc

ec

soil

nh4

pbw

blan
41

Results of the Round 5 PSAT modeling for Central Indiana fine particle monitors show the 

highest pollutant contributors to base-case and future year fine particle concentrations are sulfate, 

organic carbon, ammonium, and nitrate. Future year modeling shows decreases in sulfates (due 

to the emission reductions from CAIR) and ammonium. The future year modeling did show 

slight increases in organic carbon and nitrates from the base-case modeled concentrations. 

7.4 Summary of Existing Modeling Results

U.S. EPA and LADCO modeling for future year design values have consistently shown that 

existing national emission control measures will bring the Central Indiana Area into attainment 

of the annual NAAQS for fine particles. Emission control measures to be implemented in the 

next several years will provide even greater assurance that air quality will continue to meet the 

standard into the future. Modeling support for CAIR has shown that future year design values 

for the Central Indiana Area will continue to attain the annual standard for fine particles with 

modeled future year design values below 15 μg/m3. U.S. EPA future year modeling of national 

emission control strategies will ensure that the Central Indiana Area will maintain lower fine 

particle concentrations with an increasing margin of safety. 

7.5 Meteorological Analysis for Central Indiana

Meteorological conditions are one of the most important factors that influence development and 

transport of fine particles. Stagnant surface conditions during any time of the year and upper air 

ridging provides conducive conditions for development and transport of fine particles. 

Ultimately, passage of surface cold fronts with a clean air mass change will lower fine particle 

readings in the Central Indiana Area. 

7.6 Surface Air Conditions Present During High Fine Particle Concentration Days

Higher annual concentrations of fine particles tend to correlate with warmer temperatures and 

lighter wind speeds, although high fine particle episodes can occur in the summer or winter. It 

should be noted that higher annual fine particle concentrations are driven by individual days with 

higher fine particle concentrations throughout the monitored year. Therefore, it is difficult to 

attribute higher fine particle concentrations to annualized meteorological rankings. Review of 

several of the higher fine particle concentration episodes over the past few years reveal that 

conditions were hot in the summer with temperatures in the middle 80o

s Fahrenheit or higher and 

average wind speeds were fairly light. Fall and winter days with higher fine particle 

concentrations had near normal temperatures, but wind speeds were very light and humidity was 

higher. 

7.7 Upper Air Conditions Present During High Fine Particle Concentrations Days

Upper air ridges and more stagnant surface wind conditions predominately affect development 

and build up of fine particles. Slow moving upper air ridges can effectively suppress mixing 

within the many levels of the atmosphere and cause pollutants to build up over time. Inversions 

or increases in temperature with a rise in altitude will prevent mixing with air from the upper 

atmosphere. These conditions can occur at any time of the year and are evident in elevated fine 
42

particle episodes in spring, summer, fall, and winter months. Review of surface and upper air 

features of higher fine particle concentration days showed stagnant surface conditions and upper 

air ridges existed on those days and helped in the buildup of fine particle concentrations. 

7.8 Analyses of Atmospheric Conditions During High Fine Particle Concentration Days

Analyses have been conducted to determine the atmospheric conditions that are most prevalent 

during higher fine particle concentration days in Indiana. LADCO applied a Classification and 

Regression Tree (CART) analysis to data from Indiana that correlated different levels of fine 

particle concentrations to meteorological conditions from 1999 to 2004 (Donna Kenski, 2005). 

This type of analysis evaluates meteorological conditions, such as temperature, pressure, wind 

speed, wind direction, relative humidity, and dew point temperatures at the surface, as well as 

morning and evening mixing heights in the upper atmosphere which were present when higher 

concentrations of fine particles were monitored. Results of this CART analysis indicated factors 

that played a larger role in higher fine particle concentrations in Indiana were warm-weather 

conditions with high dew points, southwest winds, and high evening mixing heights. Previous 

day’s concentrations of fine particles play a key role in higher impacts as well. 

Fine particles are made up of several constituents, including direct PM2.5, sulfates, nitrates, 

ammonium, organic carbon, and elemental carbon. Depending on the time of the year, 

concentrations of fine particle constituents vary, with nitrates being more prevalent in the winter 

and sulfates more prevalent in the summer. Sulfate and nitrate emission reductions have the 

biggest impact on lower future year fine particle concentrations. 

7.9 Summary of Air Quality Index Days in Central Indiana

An analysis was conducted to review the daily fine particle concentrations over a year to 

determine the Air Quality Index (AQI) trends. Chart 7.8 shows by year (2001 through 2010), the 

percentage number of days during the calendar year which fine particle concentrations reached 

the AQI ranges for “Good” (0 to 15.3 μg/m3

), “Moderate” (15.4 μg/m3 to 40.4 μg/m3), and 

“Unhealthy for Sensitive Groups (USG)” (40.5 μg/m3

 to 65.4 μg/m3). There were no days 

during which fine particle levels reached the “Unhealthy” level of 65.5 μg/m3 to 150.4 μg/m3. 
43

Chart 7.8 

Distribution of PM2.5 Concentration Days in Central Indiana on the AQI Levels of Health 

Table 7.5 shows how the years ranked for the three AQI ranges. The year 2009 had the most 

“Good” concentration days during the 10-year period analyzed (2001 through 2010). The year 

2007 had the most “Moderate” concentration days and the year 2005 had the most “USG” 

concentration days with no days recorded in 2003, 2004, 2006, 2008, and 2009. As can be seen, 

weather plays a large role in fine particle concentration development and transport as 2001, 

2002, 2005, and 2007 were warmer than normal summers which translated to moderate and 

unhealthy for sensitive group levels of air quality. 

Table 7.5 

Ranking and Percentage of Highest Number of Days 

at AQI Levels of Health Concern 

Ranking Good Moderate 

Unhealthy for 

Sensitive Group 

1st 2009 – 72% 2007 – 51% 2005 – 2% 

2nd 2006 – 69% 2001 – 50% 2001 – 2% 

3rd 2004 – 67% 2002 – 47% 2002 – 1% 

4th 2008 – 64% 2005 – 45% 2010 – 1% 

5th 2003 – 60% 2003 – 40% 2007 – 1% 

6th 2010 – 59% 2010 – 40% 

7th 2005 – 53% 2008 – 36% 

8th 2002 – 52% 2004 – 33% 

9th 2001 – 48% 2006 – 31% 

10th 2007 – 48% 2009 – 28% 

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Good Moderate USG

Percentage of Year

Year
44

7.10 Summary of Meteorological Analysis for Central Indiana

Annual fine particle concentrations in the Central Indiana Area are driven by higher fine particle 

concentration days that can occur during any time of the year. Conditions that are most 

prevalent during higher fine particle concentration days are lighter winds, higher relative 

humidity, and above average temperatures in the summer, and near normal temperatures in the 

fall, winter, or spring. Approximately 70% of the days when PM2.5 concentrations were in the 

USG range occurred in the summer months with maximum high temperatures of 80oF or above. 

Weather plays a large role in fine particle concentration development and transport as 2001, 

2002, 2005, and 2006 were warmer than normal summers which translated to more days of 

moderate and unhealthy for sensitive group levels of air quality. Upper air weather patterns 

generally include ridging over the area with stagnant conditions at the surface caused by lower 

mixing heights and stable conditions for summer episodes and ridging or troughs over the area in 

the fall, winter, or spring episodes. Surface winds from any direction can transport pollutants 

from surrounding areas into the Central Indiana Area. Nitrates are bigger contributors to fine 

particle concentrations in the winter and sulfates are bigger contributors to fine particle 

concentrations in the summer. 

8.0 CORRECTIVE ACTIONS 

8.1 Commitment to Revise Plan

As noted in Section 4.6, IDEM commits to review and revise, as appropriate, its Maintenance 

Plan eight years after redesignation, as required by Section 175A of the CAA. 

8.2 Commitment for Contingency Measures

IDEM will monitor fine particle concentrations to determine whether trends indicate higher 

values or whether emissions appear to be increasing. If it is determined that fine particle levels 

and emissions are increasing and action is necessary to reverse that trend, IDEM will take action 

to reverse the noted trend, prior to a violation of the standard occurring. 

IDEM commits to adopt and expeditiously implement necessary corrective action in accordance 

with an Action Level Response described below. 

Action Level Response

An Action Level Response shall be prompted whenever a violation of the standard (three-year 

average annual arithmetic mean value of 15.1 μg/m3

 or greater) occurs. In the event that the 

Action Level is triggered and is not found to be due to an atypical unfavorable meteorological 

condition, exceptional event, malfunction or noncompliance with a permit condition or rule 

requirement, IDEM will determine additional control measures needed to assure future 

attainment of the annual NAAQS for fine particles. In this case, measures that can be 

implemented in a short time will be selected in order to be in place within eighteen months from 

the end of the year that prompted the Action Level Response. 
45

Control Measure Selection and Implementation

Adoption of any additional control measures is subject to the necessary administrative and legal 

processes. This process will include publication of notices, an opportunity for public hearing, 

and other measures required by Indiana law for rulemaking by state environmental boards. 

If a new measure or control is already promulgated and scheduled to be implemented at the 

federal or state level, and that measure or control is determined to be sufficient to address the 

upward trend in air quality, additional local measures may be unnecessary. Furthermore, IDEM 

will submit to U.S. EPA an analysis to demonstrate the proposed measures are adequate to return 

the area to attainment. 

8.3 Contingency Measures

Contingency measures to be considered will be selected from a comprehensive list of measures 

deemed appropriate and effective at the time the selection is made. Listed below are example 

measures that may be considered. The selection of measures will be based upon costeffectiveness, emission reduction potential, economic and social considerations, or other factors 

that IDEM deems appropriate. IDEM will solicit input from interested and affected persons in 

the maintenance area prior to selecting appropriate contingency measures. All of the listed 

contingency measures are potentially effective or proven methods of obtaining significant 

reductions of fine particle precursor emissions. Because it is not possible at this time to 

determine what control measure will be appropriate at an unspecified time in the future, the list 

of contingency measures outlined below is not comprehensive. IDEM anticipates that if 

contingency measures should ever be necessary, it is unlikely that a significant number (i.e., all 

those listed below) will be required. 

1) Alternative fuel and diesel retrofit programs for fleet vehicle operations. 

2) Require NOx or SO2 controls on new minor sources (less than 100 tons). 

3) Wood stove change out program. 

4) Idle restrictions. 

5) Broader geographic applicability of existing measures. 

6) One or more transportation control measures sufficient to achieve at least a 0.5% 

reduction in actual area wide precursor emissions. Transportation measures will be 

selected from the following, based upon the factors listed above, after consultation 

with affected local governments: 

a) Trip reduction programs, including, but not limited to, employer-based 

transportation management plans, area-wide rideshare programs, work 

schedule changes, and telecommuting. 

b) Transit improvements. 

c) Traffic flow improvements. 

d) Other new or innovative transportation measures not yet in widespread use 

that affected state and local governments deem appropriate. 
46

No contingency measure shall be implemented without providing the opportunity for full public 

participation during which the relative costs and benefits of individual measures, at the time they 

are under consideration, can be fully evaluated. 

9.0 PUBLIC PARTICIPATION

Indiana published notification for a public hearing and solicitation for public comment 

concerning the draft Redesignation Petition and Maintenance Plan in the Indianapolis Star, 

Indianapolis, Indiana on April 15, 2011. 

A public hearing to receive comments concerning the redesignation request was conducted on 

May 17, 2011 at the Indianapolis-Marion County Library-West Indianapolis Branch, located at 

1216 S. Kappes Street, Indianapolis, Indiana. The public comment period closed on May 19, 

2011; no comments were received by the agency concerning this submission. Appendix K 

documents the public hearing process and includes a copy of the public notice, certifications of 

publication, and transcript from the public hearing. 

10.0 CONCLUSIONS 

The Central Indiana Area has attained the annual NAAQS for fine particles. This petition 

demonstrates that the Central Indiana Area has complied with the applicable provisions of the 

CAA regarding redesignation of nonattainment areas for fine particles. IDEM has prepared a 

State Implementation and Maintenance Plan that meets the requirement of Section 110(a)(1) of 

the CAA. 

Indiana has performed an analysis that shows the air quality improvements are due to permanent 

and enforceable measures and that additional significant regional NOx and SO2 reductions 

following implementation of the Phase II NOx SIP Call rule, and CAIR or its replacement rule 

will ensure continued compliance (maintenance) with the standard. Furthermore, emission 

projections indicate that NOx and SO2 emissions will continue to decline, ensuring that the area 

continues to maintain compliance with the standard and provide for an increased margin of 

safety. Based on this presentation, the Central Indiana nonattainment area for fine particles 

meets the requirements for redesignation under the CAA (Section 107(d)(3)) and U.S. EPA 

guidance for fine particles. 

Consistent with the authority granted to U.S. EPA, the State of Indiana requests that the Central 

Indiana nonattainment area for fine particles be redesignated to attainment for the annual fine 

particles standard simultaneously with U.S. EPA approval of this Indiana State Implementation 

and Maintenance Plan.