INDIANA DEPARTMENT OF ENVIRONMENTAL MANAGEMENT

We Protect Hoosiers and Our Environment.

Mitchell E. Daniels Jr. 100 North Senate Avenue

IDEM

Thomas W. Easterly

Commissioner

April 3, 2008

(317) 232-8603

Toll Free (800) 451-6027

www.idem.lN.gov

Ms. Mary A. Gade

Regional Administrator

U.S. Environmental Protection Agency

Region V

77 West Jackson Boulevard

Chicago, IL 60604-3950

Re: Request for Redesignation and

Maintenance Plan for Fine Particle

Attainment in the Northwest Indiana

Nonattainment Area

Dear Ms. Gade:

The Indiana Department ofEnvironmental Management (IDEM) hereby submits a

Redesignation Petition and Maintenance Plan for the Fine Particle Northwest Indiana

Nonattainment Area, consisting of Lake and Porter counties, which were designated as

nonattainment ofthe annual standard for fine particles on AprilS, 2005. IDEM conducted a

public hearing concerning the Redesignation Petition and Maintenance Plan on February 27, 2008

and the public comment period concluded on March 11,2008.

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

response to substantive comments.

The attached document consists ofthe following:

Redesignation Petition and Maintenance Plan

• A formal request that Lake and Porter counties be redesignated to attainment and reclassified

as maintenance. It contains and meets the requirements set forth in Section 107 ofthe Clean

Air Act and in U.S. EPA Redesignation Guidance.

• A maintenance year of2020 is established and 2010 is analyzed as an interim year.

• The appendices ofthe document contain historic air quality trend data, projected emission

inventory data and thorough documentation ofthe mobile emissions analysis.

• A summary of and response to substantive oral and written comments.

M.Gade

Recycled Paper (1) An Equal Opportunity Employer Please Recycle
Page 2

Motor Vehicle Emissions Budgets

• Contained in the Redesignation Petition is a new Motor Vehicle Emissions Budget for 2010

and 2020. The Northwest Indiana Regional Planning Commission's travel demand model and

MOBILE6 were used to determine emissions for the annual fine particle nonattainment area.

• A conservative margin ofsafety was applied to the 2010 and 2020 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 default vehicle age distribution.

IDEM hereby requests that the U.S. EPA proceed with review and approval ofthis submittal.

If you have any questions or need additional information, please contact Scott Deloney, Chief, Air

Programs Branch, at (317) 233-5694.

S~~erely y~ours, / )

~~ Commissioner

Office ofAIr Quah~,/'

DM/sad/pad

Attachments

cc: Jay Bortzer, US EPA (no enclosures)

John Mooney, US EPA (no enclosures)

Cheryl Newton, US EPA (no enclosures)

Pat Morris, US EPA (w/enclosures)

Steve Rosenthal, US EPA (w/enclosures)

Scott Deloney, IDEM

Pat Daniel (IDEM)
REQUEST FOR REDESIGNATION 

AND 

MAINTENANCE PLAN 

UNDER THE ANNUAL 

NATIONAL AMBIENT AIR QUALITY STANDARD 

FOR 

FINE PARTICLES 

Lake and Porter Counties, Indiana

Prepared By: 

The Indiana Department of Environmental Management 

Office of Air Quality 

April 2008 
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i

TABLE OF CONTENTS 

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

1.1 Background ................................................................................................................................2 

1.2 Geographical Description ..........................................................................................................2 

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 Standard ..........................................5 

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

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

3.2 Ambient Fine Particles Monitoring Data ...................................................................................6

3.3 Indiana’s Culpability ..................................................................................................................9 

3.4 Quality Assurance ....................................................................................................................23 

3.5 Continued Monitoring ..............................................................................................................23 

4.0 EMISSION INVENTORY ....................................................................................................23 

4.1 Emission Trends.......................................................................................................................23 

4.2 Base Year Inventory ................................................................................................................28 

4.3 Emission Projections ................................................................................................................28 

4.4 Demonstration of Maintenance ................................................................................................31 

4.5 Permanent and Enforceable Emissions Reductions .................................................................31 

4.6 Provisions for Future Updates .................................................................................................31 

5.0 TRANSPORTATION CONFORMITY BUDGETS...........................................................32 

5.1 On-Road Emissions Estimations..............................................................................................32 

5.2 Overview ..................................................................................................................................32 

5.3 Best Available Data .................................................................................................................32 

5.4 Analysis Years .........................................................................................................................33 

5.5 Emission Estimations ...............................................................................................................34 

5.6 Motor Vehicle Emission Budget ..............................................................................................34 
ii

6.0 CONTROL MEASURES AND REGULATIONS ..............................................................35

6.1 Reasonably Available Control Technology (RACT) ...............................................................35 

6.2 Implementation of Past SIP revisions ......................................................................................35 

6.3 Nitrogen Oxides (NOx) Rule ....................................................................................................39 

6.4 Measures Beyond Clean Air Act SIP Requirements ...............................................................40 

6.5 Controls to Remain in Effect ...................................................................................................43 

6.6 New Source Review Provisions ...............................................................................................43 

7.0 PHOTOCHEMICAL MODELING .....................................................................................44

7.1 Summary of Modeling Results to Support Federal Rulemakings ...........................................44 

7.2 Speciated Modeled Attainment Test/Particulate Source Apportionment Analysis .................44 

7.3 Summary of Modeled Results ..................................................................................................46 

8.0 CORRECTIVE ACTIONS ...................................................................................................47

8.1 Commitment to Revise Plan ....................................................................................................47 

8.2 Commitment for Contingency Measures .................................................................................47 

8.3 Contingency Measures .............................................................................................................47 

9.0 PUBLIC PARTICIPATION ................................................................................................49

10.0 CONCLUSIONS ..................................................................................................................49 

FIGURES

Figure 3.1 Chicago Fine Particles Nonattainment Area ..................................................................6 

Figure 3.2 Chicago-Indiana PM2.5 Monitoring Locations .............................................................10 

Figure 3.3 Map of the Cicero, IL Monitor Location ......................................................................11 

Figure 3.4 Inset 1A Large Rail Yard .............................................................................................12 

Figure 3.5 Inset 1B Rail Yard to Diesel Truck Piggy Back Operation .........................................12 

Figure 3.6 Map of the Wilson Ave., IL Monitor Location ............................................................13 

Figure 3.7 Wind Rose, Back Trajectories and AIRNOW Data for October 27, 2004 ...................17 

Figure 3.8 Wind Rose, Back Trajectories and AIRNOW Data for February 3, 2005 ...................19 

Figure 3.9 Wind Rose, Back Trajectories and AIRNOW Data for January 23, 2006 ...................21 

Figure 7.1 PM2.5 Source Apportionment Results for Chicago 2012 ..............................................46 

TABLES

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

Table 3.1 Monitoring Data for Lake and Porter Counties (Annual Design Values).. .....................7 

Table 3.2 Monitoring Data for Lake and Porter Counties (2004-2006 Design Values) ..................8 

Table 3.3 Comparison of Regional High Monitor Values .............................................................16 

Table 3.4 PM2.5 Monitor Values for October 27, 2004 ................................................................18 

Table 3.5 PM2.5 Monitor Values for February 3, 2005 ................................................................20 
iii

Table 3.6 PM2.5 Monitor Values for January 23, 2006 ................................................................22 

Table 4.1 Comparison of 2005 Estimated and 2020 Projected Emission Estimates ....................30 

Table 5.1 Emission Estimates for On-Road Mobile Sources ........................................................34 

Table 5.2 Mobile Vehicle Emission Budgets in Tons Per Year ....................................................34 

Table 6.1 Trends in Annual EGU NOx Emissions Statewide in Indiana .......................................40 

Table 7.1 LADCO’s Round 5 Modeling Results for the Clean Air Interstate Rule ......................44 

Table 7.2 LADCO’s Round 4 PSAT/SMAT Modeling Results – Lake County ...........................45 

Table 7.3 LADCO’s Round 4 PSAT/SMAT Modeling Results – Porter County .........................45 

 

GRAPHS

Graph 3.1 Trends in Lake and Porter Counties’ Fine Particles Design Values ...............................9 

Graph 3.2 PM2.5 Maximum Monitored Values ............................................................................15 

Graph 4.1 PM2.5 Point Source Emissions Trends – Lake and Porter Counties ............................24 

Graph 4.2 NOx Point Source Emissions Trends - Lake and Porter Counties ..............................24 

Graph 4.3 SO2 Point Source Emissions Trends – Lake and Porter Counties ..............................24 

Graph 4.4 Statewide NOx Emissions from Electric Generating Units ...........................................25 

Graph 4.5 Lake and Porter Counties NOx Emissions from Electric Generating Units .................26 

Graph 4.6 NOx Emissions Trends .................................................................................................27 

Graph 4.7 SO2 Emissions Trends ..................................................................................................27 

Graph 4.8 PM2.5 Emissions Trends ..............................................................................................27 

Graph 4.9 Comparison of 2005 Estimated and 2020 Projected NOx Emissions for Northwest 

Indiana ...........................................................................................................................................29 

Graph 4.10 Comparison of 2005 Estimated and 2020 Projected SO2 Emissions for Northwest 

Indiana ...........................................................................................................................................29 

Graph 4.11 Comparison of 2005 Estimated and 2020 Projected PM2.5 Emissions for Northwest 

Indiana ...........................................................................................................................................30 

APPENDICES

A Air Quality System (AQS) and IDEM Monitor Data 

A-1 2007 Monitoring Data Supplement 

A-2 2007 Monitoring Data Analysis 

B NOx, SO2 and Direct PM2.5 Point Source Emissions (2002-2005) 

C NOx, SO2 and Direct PM2.5 Emission Trends, All Sources (2002-2005) 

C-1 Indiana 2002 Emissions Inventory SIP 

C-2 LADCO’s 2005 Emissions Inventory TSD 

D NOx and SO2 Emissions from Electric Generating Units 

E NOx, SO2 and Direct PM2.5 2005 Base Year Emissions Inventory and 2010 and 2020 

Projected Emissions 

E-1 IDEM’s Emissions Inventory Standard Operating Procedure 

F Example Mobile Source Input/Output Files 

G Public Participation Process Documentation 
iv

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1

REQUEST FOR REDESIGNATION AND MAINTENANCE PLAN 

UNDER THE 

NATIONAL AMBIENT AIR QUALITY STANDARDS 

FOR 

FINE PARTICLES 

LAKE AND PORTER COUNTIES, INDIANA 

1.0 INTRODUCTION

 

This document supports Indiana’s request that Lake and Porter counties, in Northwest Indiana be 

redesignated from nonattainment to attainment of the annual standard for fine particles. 

Although the 2001 through 2003 design value for the East Chicago monitoring site in Lake 

County resulted in a nonattainment designation for Lake and Porter counties, the 2002 through 

2004 monitored design values for all monitor sites in both counties demonstrated attainment. The 

United States Environmental Protection Agency (U.S. EPA) originally designated counties under 

the annual standard for fine particles based on 2001 through 2003 monitoring data in December 

2004. However, the U.S. EPA withdrew a number of counties identified as nonattainment based 

on the 2002 through 2004 data prior to the effective date of designations (April 5, 2005) due to 

the fact that those counties measured air quality that met the standard at the close of 2004. 

Though Lake and Porter counties monitored attainment at the close of 2004, and the State of 

Indiana requested that the counties be classified in accordance with the measured air quality, the 

U.S. EPA proceeded by designating the counties nonattainment effective April 5, 2005. Lake and 

Porter counties continued to record three (3) years of quality assured ambient air quality 

monitoring data for the years 2003 through 2005 and 2004 through 2006, demonstrating 

continued compliance with the annual fine particles standard. 

This document incorporates ambient monitoring data for fine particle concentrations through 

2006. IDEM will supplement this document with 2007 ambient monitoring data, including the 

2005-2007 design values, as soon as the data are quality assured. This supplement will be 

provided in conjunction with this draft document as soon as it’s available, which should be late 

February 2008, prior to the close of the comment period. 

Indiana’s request to have the area redesignated is based on Section 107 (d) (3) (D) of the Clean 

Air Act (CAA), which states: 

 “The Governor of any State may, on the Governor’s own motion, submit to the 

Administrator a revised designation of any area or portion thereof within the State. Within 18 

months of receipt of a complete State redesignation submittal, the Administrator shall approve or 

deny such redesignation. The submission of a redesignation by a Governor shall not affect the 

effectiveness or enforceability of the applicable implementation plan for the State”. 

1.1 Background
2

The Clean Air Act Amendments of 1990 (CAAA) require areas designated as nonattainment for 

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

expeditiously attain and maintain the standard. In 1997, the U.S. EPA set daily and annual 

ambient air quality standards for fine particles as shown in Table 1.1 below. The standards were 

legally challenged and upheld by the U.S. Supreme Court in February of 2001. In 1999, Indiana 

began monitoring for fine particles. The U.S. EPA designated areas under the 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 Fine Particles 

Standards (PM2.5) 

15 μg/m3

Annual arithmetic mean, 

averaged over 3 years 

65 μg/m3

24-hour average, 98th percentile, 

averaged over 3 years 

2006 Fine Particles 

Standards (PM2.5) 

15 μg/m3

Annual arithmetic mean, 

averaged over 3 years 

35 μg/m3

24-hour average, 98th percentile, 

averaged over 3 years 

Note: The Northwest Indiana Area meets the 1997 annual and 24-hour NAAQS’ for fine particles. U.S. EPA 

is scheduled to finalize designations for the 2006 24-hour standard in December 2009. Since this area is 

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

addresses the annual standard. However, as documented in Commissioner Easterly’s December 17, 2007 

letter to U.S. EPA Regional Administrator Gade, both Lake and Porter Counties currently meet the new 24-

hour standard. 

Indiana shares U.S. EPA’s goal of ambient air quality that meets national health standards and 

has made substantial progress towards that goal since passage of the Clean Air Act over 30 years 

ago. Indiana intends to continue this progress until Indiana’s air quality continually meets all 

national ambient air quality standards throughout the state. U.S. EPA’s designation of Lake and 

Porter counties as nonattainment of the annual fine particles standard has resulted in disparate 

treatment of Lake and Porter counties in comparison to other counties across the country, 

including some within the same Metropolitan Statistical Area (MSA). 

The purpose of this document is to demonstrate that Lake and Porter counties should be 

separated from the rest of the Chicago nonattainment area for fine particles, and redesignated to 

attainment. Lake and Porter counties do not significantly impact monitored violations in the 

Chicago area and additional controls in Lake and Porter counties will not provide for attainment 

of the standard in the Chicago area. Therefore, this document requests that Lake and Porter 

counties be properly designated as attaining the standard, addresses all redesignation 

requirements, and provides additional information to support continued compliance with the 

annual standard for fine particles. 

 1.2 Geographical Description of Indiana’s Portion of Nonattainment Area

Lake and Porter counties are located in Northwest Indiana and contain cities such as Gary, 

Hammond, East Chicago, Portage and Valparaiso. Lake and Porter counties are bordered by 

Lake Michigan to the north, the Indiana counties of Newton and Jasper to the south and LaPorte 
3

County to the east. The Illinois counties of Cook, Kankakee and Will border Lake and Porter 

counties to the west. This area is depicted in Figure 3.1. 

 1.3 Status of Air Quality

Fine particles monitoring data for every three-year period since the three-year period ending in 

2004, including the most recent three (3) years, 2004 through 2006, demonstrates that air quality 

meets the annual fine particles standard in Lake and Porter counties. Technical analysis, as 

summarized in this document, also demonstrates that Indiana’s portion of the nonattainment area 

does not contribute to monitored violations of the standard within the Illinois portion of the 

nonattainment area. These facts, accompanied by the permanent and enforceable reductions in 

emission levels discussed in Section 4.0, justifies a redesignation to attainment for Indiana’s 

portion of the nonattainment area based on Section 107(d)(3)(E) of the CAAA. 

2.0 REDESIGNATION REQUIREMENTS 

2.1 General

Section 110 and Part D of the CAAA lists 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. 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 

CFR 50.7, has been attained. Fine particles 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 58.10, 

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

public view. 

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 the most recent 

three (3) consecutive years of complete quality assured data. 

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

appropriate monitoring network to verify maintenance of the attainment status. 

2.3 Emission Inventory 
4

1) A comprehensive emission inventory of fine particles and fine particle precursors 

completed for the base year. (2005) 

2) A projection of the emission inventory to a year at least ten (10) years following 

redesignation. 

 

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

annual fine particles standard. 

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 annual updates of the inventory to enable tracking of the 

emission levels, including an annual emission statement from major sources. 

2.4 Modeling Demonstration 

While no modeling is required for redesignating nonattainment areas, the Indiana Department of 

Environmental Management (IDEM) has evaluated the results of regional photochemical 

modeling to demonstrate that compliance with the standard will be maintained. This modeling is 

discussed in Section 7.0 of this document. 

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. 

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 (1) 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 Standard
5

1) A commitment to submit a revised plan eight (8) years after redesignation. 

2) A commitment to expeditiously enact and implement additional contingency 

control measures 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 direct PM2.5, NOx and SO2 sources potentially subject to future controls. 

3.0 FINE PARTICLES MONITORING

3.1 Fine Particles Monitoring Network

There are currently eight monitors measuring fine particle concentrations in Lake and Porter 

counties. These monitors are located as follows: Lake County (Gary Water Plant1

, Ivanhoe 

School, Eldon Ready School, Franklin School, Purdue and Robertsdale); and Porter County 

(Dunes National Lakeshore and Ogden Dunes Water Treatment Plant). The eight monitors are 

currently operated by IDEM’s Office of Air Quality (OAQ). A listing of the monitor readings 

from 2000 through 2006 are shown in Table 3.1 and were retrieved from the U.S. EPA’s Air 

Quality System (AQS). The locations of the monitoring sites and the respective site identifiers 

(refer to Table 3.2) for this nonattainment area are shown in Figure 3.1. 

IDEM’s OAQ also operates two monitors in Lake and Porter counties that collect background 

and/or source oriented fine particle concentrations. While these monitors are not used to 

determine attainment with the annual fine particles standard, the monitoring values are included 

as supporting material in Appendix A. 

 

1

 Since the Gary Water Plant monitoring site began operation in July 2005 there are only two years of data available 

at this time. 
6

Figure 3.1 

Chicago Nonattainment Area for Fine Particles 

Oswego Township

Aux Sable Township

Goose Lake Township

170971007

171110001

170310057

170310052

170314007

170890003

170434002 170890007

170314201

170316005

170313301

171971002

181270024 181270020

180892004

180890027

170310076

170312001

180891003

180890006

170310022

180892010

170310050

Will

Cook

Lake

Kane

Lake

b

Berrien

LaPorte

Porter

McHenry

Walworth

V

Grundy

Marshall

Racine

Starke

Kendall

St. Joseph

DuPage

Kenosha

180890031

Chicago Nonattainment Area for Fine Particles

PM2.5 Monitor

Background PM 2.5 Monitor

Attainment/Unclassifiable

Nonattainment

3.2 Ambient Fine Particles Monitoring Data

The following information is taken from U.S. EPA's "Guideline on Data Handling Conventions 

for the PM NAAQS," EPA-454/R-99-008, April 1999. 

Three (3) complete years of fine particle monitoring data is required to demonstrate attainment at 

a monitoring site. The annual fine particles ambient air quality standard is met at an ambient air 

quality monitoring site when the three (3) 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. 

Three (3) significant digits must be carried in the computations and values are rounded to the 

nearest 0.1 μg/m3

. Round decimals 0.05 or greater up and those less than 0.05 down, 15.049 

μg/m3

 is the largest concentration that is less than, or equal to 15.0 μg/m3. Therefore, for the 

purposes of this request, the annual fine particles standard is considered to be 15.0 μg/m3

. 

Values equal to or below 15.0 μg/m3 meet the standard; values equal to or greater than 15.1 

μg/m3

 exceed the standard. 
7

These data handling procedures are applied on an individual basis at each monitor in the area. 

An area is in compliance with the annual fine particles standard if, and only if, the monitoring 

site meets the NAAQS. An individual site’s three (3) year average of the annual average fine 

particle concentration is also called the site’s design value. The air quality design value for the 

area is the highest design value among all sites in Lake and Porter counties. Table 3.1 outlines 

the 2000 through 2006 design values for the active fine particle monitoring sites in Lake and 

Porter counties. As mentioned above, only one monitor in Lake County violated the annual fine 

particles standard in 2001-2003, however all monitors attained the standard the next year, based 

on the 2002-2004 design values. 

Table 3.1 

Monitoring Data for Lake and Porter Counties 

(Three-Year Design Values)

Site # City Site Name 

Three Year Design Values 

(ug/m3

) 

00-02 01-03 02-04 03-05 04-06 

18-089-0006 East Chicago Franklin School 15.6 15.2 14.2 14.5 14.0 

18-089-0027 Highland Eldon Ready School 14.6 14.6 13.8 14.1 13.5 

18-089-0031 Gary Water Plant - Madison Site began operation in 07/051

18-089-1003 Gary Ivanhoe School 15.2 14.8 14.1 14.3 13.7 

18-089-2004 Hammond Purdue 15.0 14.9 14.2 14.4 13.8 

18-089-2010 Hammond Robertsdale 14.9 14.9 13.9 14.1 13.6 

18-127-0020 Dunes Natl. Lakeshore 13.5 13.4 12.8 13.0 12.3 

18-127-0020 Ogden Dunes Water Treatment Plant 14.3 13.8 13.2 13.3 12.9 

value above the standard 

Incomplete Data 

 

In accordance with Section 110 of the CAA, monitoring data must demonstrate that the threeyear average of annual values, based on data from all monitoring sites in the area or its affected 

downwind environs, are at or below 15.0 micrograms per cubic meter (μg/m3). This showing 

must rely on the most recent three (3) consecutive years of complete quality assured data. This 

data are shown in Table 3.2. 
8

Table 3.2 

Monitoring Data for Lake and Porter Counties 

(2004-2006 Design Values) 

SITE ID COUNTY SITE NAME YEAR 

Annual Average 2004-2006 Average

μg/m3 μg/m3

18-089-0006 Lake Franklin School 2004 13.18 

14.0

18-089-0006 Lake Franklin School 2005 15.76 

18-089-0006 Lake Franklin School 2006 13.18 

18-089-0027 Lake Eldon Ready School 2004 12.82 

13.5

18-089-0027 Lake Eldon Ready School 2005 15.46 

18-089-0027 Lake Eldon Ready School 2006 12.29 

18-089-1003 Lake Ivanhoe School 2004 12.92 

13.7

18-089-1003 Lake Ivanhoe School 2005 15.71 

18-089-1003 Lake Ivanhoe School 2006 12.57 

18-089-2004 Lake Purdue 2004 13.26 

13.8

18-089-2004 Lake Purdue 2005 15.4 

18-089-2004 Lake Purdue 2006 12.67 

18-089-2010 Lake Robertsdale 2004 12.47 

13.6

18-089-2010 Lake Robertsdale 2005 15.59 

18-089-2010 Lake Robertsdale 2006 12.79 

18-127-0020 Porter Dunes Natl. Lakeshore 2004 11.84 

12.3

18-127-0020 Porter Dunes Natl. Lakeshore 2005 14 

18-127-0020 Porter Dunes Natl. Lakeshore 2006 11.02 

18-127-0024 Porter Water Treatment Plant 2004 12.38 

12.9

18-127-0024 Porter Water Treatment Plant 2005 14.59 

18-127-0024 Porter Water Treatment Plant 2006 11.81 

Note: The Gary Water Treatment Plant monitor (site # 18-089-0031) is not included in Table 3.2, 

Graph 3.1, or Figure 3.2 because three complete years of data are not available. The site began 

operation in mid-2005. 

Graph 3.1 shows the trend in design values for Lake and Porter counties over the past seven 

years. A comprehensive list of the eight fine particle monitoring site’s design values over this 

period is in Appendix A. The area's design values have continued to trend downward as 

emissions have declined due to such programs as the Acid Rain program, the NOx SIP Call and 

cleaner automobile engines and fuels, both regionally and locally. 
9

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 Rule was adopted on June 6, 2001 (326 IAC 10-3 and 10-4). 

The elevated 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 2004 is not the result of unusually favorable 

meteorological conditions. It is expected that this downward trend will continue as the above 

programs continue and the U.S. EPA Clean Air Interstate Rule (CAIR) is implemented. 

Graph 3.1 

Trends in Lake and Porter Counties’ Fine Particles Design Values 

2000 through 2006 

Controlling Monitor – Franklin 

12.0

12.5

13.0

13.5

14.0

14.5

15.0

15.5

16.0

2000-2002 2001-2003 2002-2004 2003-2005 2004-2006

ug/m3

Standard Franklin School Eldon Ready School

Ivanhoe School Purdue Robertsdale

Dunes Natl. Lakeshore Water Treatment Plant

3.3 Indiana’s Culpability

Figure 3.2 shows the monitors located within the Chicago nonattainment area along with the 

monitoring site number and the 2004 through 2006 design value. Indiana has conducted an 

evaluation to determine the impacts of Lake and Porter county sources on fine particles monitors 

in the Chicago nonattainment area. As a result, Indiana has determined that emissions from Lake 

and Porter counties do not affect the downwind area’s ability to attain the fine particles standard. 

There are only two monitors in the Chicago nonattainment area that are currently violating the 

fine particles standard (Wilson Ave, 170310052 and Cicero, 170316005). 
10

Figure 3.2 

Chicago-Indiana PM2.5 Monitoring Locations 

Oswego Township

Aux Sable Township

Goose Lake Township

170971007

11.6

171110001

12.3

170310057

14.6

170310052

15.6

170314007

12.5

170890003

13.0

170434002

13.6

170890007

14.2

170314201

12.5

170316005

15.2

170313301

15.0

171971002

13.1

181270024

12.9

181270020

12.3

180892004

13.8

180890027

13.5

170310076

14.8

170312001

14.6

180891003

13.7 180890006

14.0

170310022

14.7

180892010

14.3

170310050

14.6

Will

Cook

Lake

Kane

Lake

Kalb

Berrien

Jasper

LaPorte

Porter

Kankakee

McHenry

Walworth

V

Pulaski Fulton

Grundy

Marshall

Starke

Kendall

St. Joseph

DuPage

Kenosha

e

Chicago Nonattainment Area for Fine Particles

PM 2.5 Monitor

Below the Standard < 15.1

Above the Standard >= 15.1

Background PM 2.5 Monitor

Attainment/Unclassifiable

Nonattainment

The monitors that are located closer to the Indiana state line and the lakefront, and should be 

more directly impacted by emissions from Lake and Porter county sources, are monitoring 

attainment of the standard (see Figure 3.2). If emissions from Lake and Porter counties were 

significantly contributing to the violating monitors in Illinois, we would expect to see higher 

levels at the monitors located between Indiana and the violating monitors as well. The Illinois 

monitors that measure values above the annual standard for fine particles are more inland and are 

most likely affected by local sources, specifically mobile source emissions. 

As shown in Figures 3.3 and 3.6, these two Illinois sites are located within close proximity of the 

convergence of several major interstates, expressways, downtown Chicago and various 

commercial and industrial regions. The Cicero monitoring site is surrounded by a massive rail 

and heavy duty diesel truck loading/transfer operation. These monitors are most greatly impacted 

by the mass of emissions in Illinois, which vastly exceeds those that may be originating from 

surrounding areas, including Lake and Porter counties. Due to its immediate proximity to 
11

multiple transportation facilities, it could be argued that the Wilson Avenue monitor location is 

more representative of a source specific site. In considering characteristics like distance from 

population and proximity to vehicular traffic, the Wilson Avenue site is very comparable to other 

monitor locations in the region that are identified as source specific (i.e., the Burr Street location 

in Lake County, Indiana).

Figure 3.3 

Cicero, IL Monitor Location 

W. Roosevelt Rd.

W. 13th St.

W. 16th St.

Inset 1B

Inset 1A

Monitor 170316005 Cicero (13th St. & 50th Ave.) S. La ram ie Ave. S. C icero Ave. S. 50 th Ave .

Monitor Location

Eisenhower Expy East

Eisenhower Expy West
12

Figure 3.4 

Inset 1-A 

Large Rail Yard 

Figure 3.5 

Inset 1-B 

Rail Yard/Diesel Truck Transfer Operation 
13

Figure 3.6 

Wilson Ave., IL Monitor Location 

Monitor 170310052 at 4850 Wilson Ave.

W. Wilson Ave.

Kennedy Expy West

Kennedy Expy East

Edens Expy West

Edens Expy East

I-90

I-94

Monitor Location

Lake and Porter counties are subject to the most stringent group of emission controls within the 

state of Indiana. This collection of permanent and enforceable controls is equally as stringent as 

those that apply elsewhere within the nonattainment area, and in some cases, more stringent. For 

example, organic carbon accounts for a significant portion of fine particle mass and it is believed 

that the majority of organic carbon in urban areas originates from mobile source emissions, 

especially poorly maintained vehicles. Indiana believes that the two monitoring sites (Cicero and 

Wilson Avenue) in Cook County, Illinois that currently measure fine particle concentrations 

above the standard are affected by “urban excess”, mostly attributable to localized mobile 

sources. 

Indiana is confident that the portion of the total vehicle miles traveled (VMT) in close proximity 

to these sites from vehicles registered in Lake and Porter counties is a small percentage of the 

total VMT affecting these monitoring sites. Regardless, vehicles registered in Lake and Porter 

counties are subject to reformulated gasoline and enhanced vehicle inspection and maintenance 
14

 

requirements. Enhanced vehicle inspection and maintenance is the most effective control for 

organic carbon. Indiana maintains a comprehensive vehicle inspection and maintenance program 

in Lake and Porter counties for all vehicles of model year 1976 and newer. Lake and Porter 

counties’ motor vehicle control program is more stringent2 than that which applies to the vast 

majority of the fleet that accounts for the VMT and long-term idling in close proximity to the 

aforementioned sites. In fact, the greatest portion of the fleet defined as “high-emitters” for 

organic carbon and other precursors are pre-1996 model year vehicles, none of which are subject 

to vehicle inspection and maintenance requirements in Illinois. 

Furthermore, as Section 7.2 illustrates, the violating monitors within the Chicago area are 

affected more by emissions deriving from Wisconsin, presumably primarily from Southeast 

Wisconsin, than from Lake and Porter counties. The U.S. EPA did not designate any portion of 

Wisconsin, including the Southeast counties, nonattainment under the annual standard for fine 

particles. For U.S. EPA to be consistent in making designations the same criteria should be 

applied to Lake and Porter counties that U.S. EPA used in exempting the Southeast Wisconsin 

area from a nonattainment designation, since both areas monitored attainment and do not 

adversely affect the downwind area’s ability to attain the standard. 

To further illustrate this point, the graphs below show the maximum monitored values for each 

month during 2004, 2005 and 2006, for various sites in the nonattainment area. To demonstrate 

geographic placement, the charts also include the Northbrook, IL site (170314201) in the far 

northern area, the Blue Island, IL site (170312001) in the southwestern part of the area, two Lake 

Co., IN sites, and one Porter Co., IN site. These charts indicate that the fine particle values for 

Wilson Avenue and Cicero monitors are significantly higher than those recorded at any Indiana 

monitor or at any of the monitors between Indiana and the area of Illinois that measures 

nonattainment. 

 

2

 The Illinois vehicle emissions testing program is limited to model years 1996 and newer. 
15

Graph 3.2 

PM2.5 Maximum Monitored Values 

(2004 – 2006) 

2004 PM2.5 Max Values

0

10

20

30

40

50

60

70

January

February

March

April

May

June

July

August

September

October

November

December

micrograms/cubic meter

Wilson Ave. Blue Island Northbrook Cicero

Ivanhoe School Roberstdale Ogden Dunes

2005 PM2.5 Max Values

0

10

20

30

40

50

60

70

January

February

March

April

May

June

July

August

September

October

November

December

micrograms/cubic meter

Wilson Ave. Blue Island Northbrook Cicero

Ivanhoe School Roberstdale Ogden Dunes

2006 PM2.5 Max Values

0

10

20

30

40

50

60

70

January

February

March

April

May

June

July

August

September

October

November

December

micrograms/cubic meter

Wilson Ave. Blue Island Northbrook Cicero

Ivanhoe School Roberstdale Ogden Dunes

These graphs also demonstrate that there is a regional 

trend or relationship between all of the monitor 

locations, with the exception of the Wilson Ave. (site 

#170316052) and the Cicero (site #170316005), IL 

sites (the two sites that exceed the standard), especially 

evident in October 2004, February, September, 

November and December 2005 and January, March, 

August and December 2006. These spikes in 

monitoring levels are unrelated to regional events, but 

rather local influences that are unrelated to Indiana. 

Indiana further analyzed the days that the monitoring levels spiked at the Wilson Avenue 

monitoring site with values substantially higher than the next highest monitor value in the region 

on that date, as shown in Table 3.3. Indiana then compared those days to wind data to determine 

the direction of prevailing winds during those days. Average hourly meteorological data was 

taken from Gary and Hammond meteorological stations, located in Lake County, as well as the 

Great Lakes Environmental Research Laboratory (GLERC) Meteorological Observation station, 

Harrison-Dever Crib, located approximately 3 miles offshore of downtown Chicago. The 

comparison for the highest monitor value days at the Wilson Avenue monitoring site showed 

winds from different directions with winds predominately from the east, south, west and 

southwest. Based on this sample of high fine particles monitor value days, while emissions from 

all surrounding areas may have small impacts, it is evident that there is no significant impact 

from Northwest Indiana. 
16

Table 3.3 

Comparison of Regional High Monitor Values 

Date 

Wilson Avenue 

Monitor Value 

(μg/m3

) 

Next Highest 

Monitor Value 

in 

Region (μg/m3

) 

Monitor 

Location 

Highest NW 

Indiana 

Monitor 

Value (μg/m3) 

Wind 

Direction 

10-27-2004 33.7 32.6 Cicero 27.8 ESE, SE 

02-03-2005 62.6 43.8 Blue Island 42.0 W, WNW 

01-23-2006 40.8 22.8 Northbrook 24.7 WSW, NNW 

 

Further analysis of high fine particles days included a back trajectory analysis, using the 

HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectory) model from National 

Oceanic and Atmospheric Administration’s (NOAA) Air Resources Laboratory (ARL). Back 

trajectory analyses provide an indication of the origin of the air from the previous day that may 

impact the Chicago, Illinois area. Back trajectory measures the winds at different heights in the 

atmosphere to determine from what locations pollutants may be picked up and transported to an 

area. The back trajectory analysis for the high fine particles monitor value days at the Wilson 

Avenue were taken from the Chicago - O’Hare International Airport show various wind 

directions and different origins of the air pollutants found in Chicago on the day of the higher 

fine particles monitor values. 

PM2.5/Meterological Data Analysis for October 27, 2004

The October 27th, 2004 wind rose and back trajectory for the Chicago area are shown below. 

On this day, the Wilson Ave. monitor had a monitored maximum value of 33.7 μg/m3

for fine 

particles. The next highest monitored value within the area was 32.6 μg/m3

at the Cicero 

monitor. 

The results of the wind rose, in Figure 3.7, show light northerly, easterly and southeasterly winds 

on that day. Archived AIRNOW fine particles data from October 26th and 27th, 2004 show the 

regional nature of fine particle concentrations during this time period. Northwest Indiana could 

be considered upwind of Chicago for this day and potential impact on the fine particle monitors 

in Illinois exists. 

Figure 3.7 

Wind Rose, Back Trajectory and AIRNOW data for October 27, 2004 
17

All winds were less than 10 

knots (11.5 miles per hour). 

These lighter winds indicate 

more stagnant surface 

conditions during the day, 

resulting in a greater impact 

from local emissions on the 

fine particle monitors in 

Illinois. 

Back Trajectory and AIRNOW data for October 27, 2004

 

The back trajectory, in Figure 3.7 above, show the air from the previous day (October 26th) came 

from Ohio, southern Michigan and northeast corner of Indiana and impacted the Chicago area on 

October 27th. AIRNOW data shows that fine particle concentrations were in the Moderate 
18

(yellow or 15 to 40 μg/m3) range of the Air Quality Index (AQI) with some areas in the 

Unhealthy for Sensitive Groups (orange or 40 to 65 μg/m3) range throughout northern Ohio, 

southern Michigan and northern Indiana for both days. While not completely eliminating 

Northwest Indiana’s potential culpability on this day, it appears that there was transport of fine 

particles and its precursors from other regions located east of Chicago, and that local sources 

contributed at least 5.0 to 6.0 μg/m3

 to the high values at these monitors. 

Table 3.4 

PM2.5 Monitored Values for October 27, 2004 

PM2.5 Monitored Values for October 27, 2004 

Site ID Monitoring Site Monitored Values 

(μg/m3) 

17-031-0052 Wilson Ave. 33.7 

17-031-2001 Blue Island 28.0 

17-031-4201 Northbrook Did not report 

17-031-6005 Cicero 32.6 

18-089-1003 Gary-Ivanhoe 27.4 

18-089-2010 Hammond-Clark H.S. 27.8 

18-127-0024 Ogden Dunes 27.2 

PM2.5/Meterological Data Analysis for February 3, 2005

The February 3rd, 2005 wind rose and back trajectory analysis for the Chicago area are shown 

below, in Figure 3.8. On this day, the Wilson Ave. monitor had a maximum monitored value of 

62.6 μg/m3 for fine particles and the next highest monitored value was 47.0 μg/m3at the Cicero 

monitor. 

The results of the wind rose, in Figure 3.8, show light westerly winds on that day. Archived 

AIRNOW fine particles data from February 2 and 3, 2005 show the regional nature of fine 

particle concentrations during this time period. Northwest Indiana could be considered 

downwind of Chicago for this day and not likely to have an impact on the fine particle monitors 

in Illinois. 

The entire upper Midwest was in the middle of a fine particles episode during this date, with fine 

particle monitored values in excess of 50.0 and 60.0 μg/m3. Meteorological conditions were such 

that a stagnant air mass was over the entire upper Midwest area and conditions were conducive 

for fine particle build-up. 

Figure 3.8 

Wind Rose, Back Trajectory and AIRNOW data for February 3, 2005 
19

The winds appear 

to have been less 

than 10 knots 

(11.5 miles per 

hour). This 

would indicate 

lighter wind 

Back Trajectory and AIRNOW data for February 3, 2005

 

The back trajectory from the previous day (February 2nd) show the air came from Iowa and 

northern Illinois on February 3rd. The wind directions at the lower levels of the atmosphere 

appear to change directions, indicating recirculation of northeast Illinois’ air from the previous 
20

day. AIRNOW data show that fine particle concentrations were in the Moderate range (yellow 

or 15 to 40 μg/m3range) of the AQI with some areas in the Unhealthy for Sensitive Groups 

(orange or 40 to 65 μg/m3) range throughout Illinois, Iowa and southern Wisconsin for both 

February 2nd and February 3rd. It appears that there is pollution transport in the upper 

atmosphere from regions west of Chicago along with recirculation of surface air from northeast 

Illinois due to a large high pressure system which persisted for several days. The unique 

meteorological conditions suppressed mixing in the atmosphere and pollutants were trapped at 

the surface. The concentrations at the regional monitoring sites, excluding the Wilson Ave. site, 

ranged within 10 to 12 μg/m3. However, the Wilson Ave. monitor had concentrations more than 

15.0 to 25.0 μg/m3 higher than other sites located in northwest Indiana or at sites between 

Indiana and the Wilson Ave. site, indicating greater local source contributions at this monitor. 

Table 3.5 

PM2.5 Monitored Values for February 3, 2005 

PM2.5 Monitored Values for February 3, 2005 

Site ID Monitoring Site Monitored Value 

(μg/m3

) 

17-031-0052 Wilson Ave. 62.6 

17-031-2001 Blue Island 43.8 

17-031-4201 Northbrook 35.8 

17-031-6005 Cicero 47 

18-089-1003 Gary-Ivanhoe 37 

18-089-2010 Hammond-Clark H.S. 42 

18-127-0024 Ogden Dunes Did not report 

PM2.5/Meterological Data Analysis for January 23, 2006 

The January 23rd, 2006 wind rose and back trajectory analysis for the Chicago area are shown 

below. On this day, the Wilson Ave. monitor had a maximum monitored value of 40.8 μg/m3 for 

fine particles and the next highest monitored value within the area was 28.7 μg/m3

. 

The results of the wind rose, shown in Figure 3.9, show southwesterly winds on this day. 

Archived AIRNOW fine particles data from January 22nd and 23rd, 2006 show the regional 

nature of fine particle concentrations during this time period with higher concentrations in the 

upper Midwest. Northwest Indiana could be considered downwind for this day, thus it is 

unlikely that it contributed to fine particle concentrations measured in Illinois. 

Figure 3.9 

Wind Rose, Back Trajectory and AIRNOW data for January 23, 2006 
21

 

Winds appear to be between 7 

and 10 knots (8 to 12 miles per 

hour) from the north and 

northwest and west and 

southwest. This would indicate 

higher wind speeds, resulting in 

more transport of fine particles 

and their precursors at the 

surface from the southwest to 

the fine particle monitors in the 

Chicago area. 

 

Back Trajectory and AIRNOW data for January 23, 2006

 

The back trajectory, shown in Figure 3.9, from the previous day (January 22, 2006) show the air 

coming from Nebraska, southern Minnesota, northern Iowa, southern Wisconsin and northern 
22

Illinois on January 23rd. AIRNOW data show that fine particle concentrations were in the range 

of 15.0 to 40.0 μg/m3 throughout southern Minnesota, northern Iowa, southern Wisconsin and 

northern Illinois. It appears that there is transport from southern Minnesota, northern Iowa, 

southern Wisconsin and northern Illinois. Northwest Indiana should be considered downwind of 

Chicago for this date, thus it is highly unlikely that Lake and Porter counties contributed to fine 

particle concentrations measured in Illinois. Meteorological data indicate that Northwest Indiana 

sources were downwind on the 23rd with higher wind speeds and monitoring data from nearby 

sites indicating local sources contributed to the higher values at Wilson Ave. The monitoring 

sites had some variation in their concentrations, within 4.0 to 7.0 μg/m3

. However, the Wilson 

Ave. monitor had concentrations at least 16.0 μg/m3 higher than other sites located between Lake 

and Porter counties and the Wilson Ave. site, indicating greater local source contributions at this 

monitor during this fine particles episode. 

Table 3.6 

PM2.5 Monitored Values for January 23, 2006

PM2.5 Monitored Values for January 23, 2006 

Site ID Monitoring Site Monitored Value 

(μg/m3) 

17-031-0052 Wilson Ave. 40.8 

17-031-2001 Blue Island 21.6 

17-031-4201 Northbrook 22.8 

17-031-6005 Cicero 28.7 

18-089-1003 Gary-Ivanhoe 24.7 

18-089-2010 Hammond-Clark H.S. 24.1 

Conclusions 

As demonstrated above, the two monitoring sites (Cicero and Wilson Avenue) in Cook County, 

Illinois that currently measure fine particle concentrations above the standard are affected by 

“urban excess”, mostly attributable to localized mobile sources. 

If emissions deriving from Lake and Porter counties were significantly contributing to the 

violating monitors in Illinois, we would expect to see similar elevated values at the sites located 

between Lake and Porter counties and the Cicero and Wilson Ave., and in Lake and Porter 

counties. 

The location of the two violating monitors in Northeast Illinois results in elevated concentrations 

representative of “urban excess”, primarily attributable to localized mobile source emissions. 

Indiana is confident that its contribution to this localized effect is negligible. 

3.4 Quality Assurance
23

IDEM has quality assured all data shown in the tables above and included in Appendix A in 

accordance with 40 CFR 58.10 and the Indiana Quality Assurance Manual. IDEM has recorded 

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

3.5 Continued Monitoring

Indiana commits to continue monitoring of fine particles 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, should changes become necessary in the future. IDEM will 

continue to quality assure the monitoring data to meet the requirements of 40 CFR 58. IDEM 

will continue to enter all data into AQS on a timely basis in accordance with federal guidelines. 

4.0 EMISSION INVENTORY 

The U.S. EPA’s Redesignation Guidance requires the submittal of a comprehensive inventory of 

fine particles and precursor emissions of fine particles (SO2, direct PM2.5 and NOx) representative 

of the year when the area achieves attainment of the annual standard for fine particles. Indiana 

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 emissions inventory related requirements include: 

o projection of the emission inventory to a year at least ten (10) years following 

redesignation; 

o a demonstration that the projected level of emissions is sufficient to maintain the 

annual fine particles standard; and, 

o a commitment to provide future updates of the inventory to enable tracking of 

emission levels during the ten (10) year maintenance period. 

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

volatile organic compounds or ammonia to be significant contributors of fine particles. The 

following subsections address each of these requirements. 

4.1 Emission Trends

Point Sources

Graphs 4.1, 4.2 and 4.3 show the trend in point source emissions of direct PM2.5, NOx and SO2

respectively that generally correspond to the years of monitored values referenced in this 

petition. The point source data is taken from Indiana's annual emissions reporting program. Point 

source emissions for NOx, SO2 and direct PM2.5 have decreased since 2002. 
24

Graph 4.1 

PM2.5 Point Source Emissions Trends – Lake and Porter Counties 

2002 and 2005 

PM2.5 Point Source Emissions Trends 

Lake and Porter Counties

0

2000

4000

6000

8000

2002 2005

Annual-Tons

PM2.5

Graph 4.2 

NOx Point Source Emissions Trends – Lake and Porter Counties 

2002 and 2005 

NOx Point Source Emissions Trends 

Lake and Porter Counties

0

15000

30000

45000

60000

2002 2005

Annual-Tons

NOx

Graph 4.3 

SO2 Point Source Emissions Trends – Lake and Porter Counties 

2002and 2005 

SO2 Point Source Emissions Trends 

Lake and Porter Counties

0

15000

30000

45000

60000

75000

2002 2005

Annual-Tons

SO2
25

EGU Sources

Regional NOx emission reductions affect fine particle levels in northwest Indiana. Graph 4.4 

depicts the substantial decrease in statewide NOx emissions from EGUs. While fine particles and 

the associated precursors are transported into this region from outside the area, this information 

provides some indication of the impact that Indiana EGU sources may have on the nonattainment 

area. The emissions are decreasing substantially in response to national programs affecting all 

EGUs such as the Acid Rain program, the NOx SIP Call and CAIR. Other sectors of the 

inventory also impact fine particle formation, but large regional sources such as EGUs have a 

substantial impact on fine particle levels. 

This data were taken from U.S. EPA's Clean Air Markets database3. 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, 

should remain at least this low through the maintenance period covered by this request. 

Graph 4.4 

Statewide NOx Emissions from Electric Generating Units 

Annual Emissions - 1999 through 2006 

Statewide NOx Emissions from EGUs

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

Annual Tons

NOx

 

3

http://www.epa.gov/airmarkets
26

Graph 4.5 

Lake and Porter Counties NOx Emissions from Electric Generating Units 

Annual Emissions - 1999 through 2006 

Northwest IN NOx Emissions from EGUs

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

40,000

45,000

50,000

1999 2000 2001 2002 2003 2004 2005 2006

Annual Tons

NOx

All Anthropogenic Sources

Periodic inventories, which include emissions from all sectors (mobile, area, non-road, and point 

sources), were prepared for 2005 and are included in Appendix C. Graphs 4.6, 4.7 and 4.8 show 

the trends for the total emissions for all anthropogenic source categories in 2002 and 2005, 

which also roughly follow the years of monitored trends discussed in Section 3.0. Graphs and 

data tables of emissions from each source category are available in Appendix C. 
27

Graph 4.6 

NOx Emissions Trends, All Sources in the Northwest Indiana Area 

2002 and 2005

NOx Trends- All Anthropogenic Sources 

Lake and Porter Counties

0

20000

40000

60000

80000

100000

120000

2002 2005

Annual-Tons

NOx

Graph 4.7 

SO2 Emissions Trends, All Sources in the Northwest Indiana Area 

2002 and 2005 

SO2 Trends- All Anthropogenic Sources 

Lake and Porter Counties

0

15000

30000

45000

60000

75000

2002 2005

Annual-Tons

SO2

Graph 4.8 

PM2.5 Emissions Trends, All Sources in the Northwest Indiana Area 

2002 and 2005 

 

PM2.5 Trends- All Anthropogenic Sources 

Lake and Porter Counties

0

3000

6000

9000

12000

15000

2002 2005

Annual-Tons

PM2.5
28

4.2 Base Year Inventory

IDEM prepared a comprehensive inventory for Lake and Porter counties, including area, mobile, 

non-road and point sources for direct PM2.5 and precursors of fine particles (nitrogen oxides and 

sulfur dioxide) for base year 2005 (the middle year of the area’s attainment design value). 

 

• Area source emissions were taken from the Indiana 2005 periodic inventory submitted to 

U.S. EPA. 

• Mobile source emissions were calculated from MOBILE6.2 produced emission factors and 

data extracted from the region’s travel-demand model. 

• Point source information was compiled from IDEM’s annual emissions statement database. 

• Biogenic emissions are not included in these summaries. 

• Non-road emissions were modeled using an estimation model provided by U.S. EPA. 

To address concerns about the accuracy of some of the categories in U.S. EPA’s non-road 

emissions model, the Lake Michigan Air Directors’ Consortium (LADCO) (Midwest Regional 

Planning Organization), contracted with two (2) companies to review the base data and make 

recommendations. One of the contractors also estimated emissions for two (2) non-road 

categories not included in U.S. EPA's non-road model. Emissions were estimated for 

commercial marine vessels and railroads. Recreational motorboat population and spatial 

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

construction equipment category were reviewed and updated based upon surveys completed in 

the Midwest and the temporal allocation for agricultural sources was also updated. 

Appendices B and C contain 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 2020 as the 

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

inventories for 2010 and 2020 for Lake and Porter counties. These emissions projections were 

prepared by IDEM, with assistance from LADCO. 

The detailed inventory information for the Northwest Indiana area for 2010 and 2020 is in 

Appendix B. 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 (2005), interim year (2010), and maintenance year (20204

) for Lake and Porter 

counties. Graphs 4.9, 4.10 and 4.11 visually compare the 2005 (base year) estimated emissions 

with the 2010 and 2020 projected emissions for Lake and Porter counties. Mobile source 

emission inventories are 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 2010 and 2018 were projected 

utilizing Annual Energy Outlook Supplemental tables. These tables were generated for the 

reference case of the Annual Energy Outlook 2007 (AE2007) using the National Energy 

Modeling System.

Graph 4.9 

 

4

 EGU emission projections for the year 2020 are based on 2018 emission estimates. 
29

Comparison of 2005 Emissions and 2010 and 2020 Projected Annual NOx Emissions 

Lake and Porter Counties 

NOx Trends- All Anthropogenic Sources by Sector 

Lake and Porter Counties

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

Area Non-road Mobile Point Total

Annual- Tons

2005 2010 2020

Graph 4.10 

 Comparison of 2005 Emissions and 2010 and 2020 Projected Annual SO2 Emissions 

Lake and Porter Counties 

SO2 Trends- All Anthropogenic Sources by Sector

Lake and Porter Counties

0

10,000

20,000

30,000

40,000

50,000

60,000

Area Non-road Mobile Point Total

Annual- Tons

2005 2010 2020

Graph 4.11 
30

Comparison of 2005 Emissions and 2010 and 2020 Projected Annual PM2.5 Emissions 

Lake and Porter Counties

Direct PM2.5 Trends- All Anthropogenic Sources by Sector

Lake and Porter Counties

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000

Area Non-road Mobile Point Total

Annual- Tons

2005 2010 2020

TABLE 4.1 

Comparison of 2005 Estimated and 2020 Projected Annual Emission Estimates 

Northwest Indiana Area 

 2005 2020 Change % Change 

NOx (tons/year) 71,282.12 41,363.20 (29,918.92) (41.97) 

SO2 (tons/year) 50,993.81 49,799.70 (1,194.11) (2.34) 

Direct PM2.5 

(tons/year) 7,434.48 8,135.17 700.69 9.42 

NOx emissions within the Northwest Indiana area are projected to decline by almost 42% 

between 2005 and 2020. Emission reduction benefits from U.S. EPA rules covering the NOx SIP 

Call, Tier 2 Motor Vehicle Emissions Standards and Gasoline Sulfur Control Requirements5

Highway Heavy-Duty Engine Rule6 and Non-Road Diesel Engine Rule7 are factored into the 

changes. Further, due to implementation of the NOx SIP Call across the eastern United States, 

fine particles and precursors for fine particle emissions entering this area are also decreased. The 

Clean Air Interstate Rule (CAIR), issued in March 2005, adopted by the Indiana Air Pollution 

Control Board on November 1, 2006, and to be implemented by 2009, will reduce regional EGU 

NOx emissions statewide by approximately another 17% in 2015. Since CAIR is a regional cap 

and trade program, it cannot be guaranteed at this time what effect it will have on EGU units 

located in Lake and Porter counties. However, regional reductions of both SO2 and NOx will be 

achieved and further benefit local air quality. 
31

4.4 Demonstration of Maintenance

Ambient air quality data from all the monitoring sites indicate that air quality in the Northwest 

Indiana area has met the NAAQS for the annual fine particles standard since the three-year 

period ending in 2004. U.S. EPA’s Redesignation Guidance (Page 9) 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 emissions rates will not cause a violation of the 

NAAQS.” Emissions projections outlined in Section 4.0 of this document clearly illustrate that 

NOx and SO2 emissions will continue to decline between 2005 (base year) and 2020 

(maintenance plan horizon). Section 7.0 further discusses the implications of these emissions 

trends and provides an analysis to support these conclusions. Therefore, air quality should meet 

the annual fine particles standard through the projected years of 2010 and 2020. 

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

once every three (3) years or annually if the SO2 potential to emit is greater than 2500 tons or the 

NOx potential to emit is greater than 2500 tons, in accordance with the Emission Statement Rule, 

326 IAC 2-6. IDEM prepares a new periodic inventory for fine particles and fine particles 

precursor emission sectors every three (3) years. These fine particles precursor emission 

inventories will be prepared for 2008, 2011, 2014 and 2017 as necessary to comply with the 

inventory reporting requirements established in the CAAA. Emissions information will be 

compared to the 2005 base year and the 2020 projected maintenance year inventories to assess 

emission trends, as necessary, to assure continued compliance with the annual fine particles 

standard. 

4.5 Permanent and Enforceable Emission Reductions

Permanent and enforceable reductions of sulfur dioxides, direct PM2.5, and oxides of nitrogen 

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, and some were due to the 

application of tighter federal standards on new vehicles and fuels. Section 6.0 identifies the 

emission control measures specific to Lake and Porter counties, as well as the implementation 

status of each measure. 

4.6 Provisions for Future Updates 

 

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

eight (8) 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 (10) 

years beyond the first ten (10) year period after redesignation. 

5 http://www.epa.gov/fedrgstr/EPA-AIR/2000/February/Day-10/a19a.htm 6 http://www.epa.gov/fedrgstr/EPA-AIR/1997/October/Day-21/a27494.htm 7 http://www.epa.gov/fedrgstr/EPA-AIR/1998/October/Day-23/a24836.htm
32

5.0 TRANSPORTATION CONFORMITY BUDGETS 

5.1 On-Road Emission Estimations

The Northwest Indiana Regional Planning Commission (NIRPC) is the Metropolitan Planning 

Organization (MPO) for the area that includes Lake, Porter and LaPorte counties. This 

organization maintains a travel demand forecast model that is used to simulate the traffic in the 

area and to predict what that traffic would be like in future years given growth expectations. The 

model is used mostly to identify where travel capacity will be needed and to determine the 

infrastructure requirements necessary to meet that need. It is also used to support the calculation 

of mobile source emissions. The travel demand forecast model is used to predict the total daily 

Vehicle Miles Traveled (VMT) and an EPA software program called MOBILE6 is used to 

calculate the emissions per mile. The product of these two outputs, once combined, is the total 

amount of pollution emitted by the on-road vehicles for the particular analyzed area. 

5.2 Overview 

Broadly described, MOBILE6 is used to generate “emission factors”, which are the average 

emissions per mile (grams/mile) for direct PM2.5 and PM2.5 precursors, including NOx and SO2. 

There are numerous variables that can affect the emission factors. The vehicle fleet (vehicles on 

the road) age and the vehicles-types have a major effect on the emission factors. The facilitytype the vehicles are traveling on (MOBILE6 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, and the area’s Inspection/Maintenance program affect the 

emission factors as well. Once emission factors are determined, the emission factor(s) is 

multiplied by the vehicle-miles-traveled (VMT) to ultimately determine the quantity of vehicle 

emissions. VMT data is generated by the region’s travel demand model. The VMT values are 

scaled to account for the differences between the model and the Highway Performance 

Monitoring System (HPMS) for the calibration base year. An example mobile source 

input/output file is included in Appendix G. 

5.3 Best Available Data 

Depending on the details of the travel demand model, much of MOBILE6 input data for 

emission factor computation can be found in the model, but some must come from other sources. 

 The NIRPC travel demand model has more detailed data than most models. While almost all 

models contain traffic speed and road-type data, the NIRPC model contains information for 

vehicle-type as well. It monitors the movement of three vehicle-types: (1) cars, (2) light freight 

trucks and buses and (3) heavy trucks. The model also does a better job of speed analysis 

because it describes three (3) times of day: (1) three AM (morning) peak hours, (2) three PM 

(afternoon) peak hours, and (3) three off peak hours. This allows for a much more thorough and 

accurate analysis of speeds over the course of the day. 

Vehicle Age Distribution

MOBILE6 has sixteen (16) different vehicle-type categories differentiated by weight. The first 

five (5) are generally passenger vehicles: cars, vans and SUVs. The others are different sized 

trucks and buses and the last is motorcycles. This MOBILE6 vehicle age distribution describes 

what fraction of each of the 16 vehicle-types is one year old, two years old, etc., up to the 25-

and-older category. MOBILE6 has a default age profile of each vehicle-type taken from national 
33

surveys. 

 

Due to its geographic proximity to Chicago, Northwestern Indiana is a through-traffic area for an 

enormous amount of freight transportation. National default age profiles make sense to use for 

freight vehicles, but for passenger vehicles, local data exists and was used for the age 

distribution for these first 5 MOBILE6 vehicle-types. 

 

Vehicle Identification Numbers (VIN) provided by the Indiana Bureau of Motor Vehicles 

(BMV) for the year 2003 for Lake and Porter counties were decoded and split into the first five 

(5) MOBILE6 vehicle-types. These age distributions are not expected to change much over time 

so they do not change for the different analysis years. 

Speeds

Speeds can be an input to MOBILE6 in two different ways. MOBILE6 assumes Local and 

Ramp facility-types have fixed speeds of 12.9 and 34.6 mph, respectively. This cannot be 

changed; only Arterial and Freeway speeds can be input to MOBILE6. There is an Average 

Speed command that allows the average Freeway or Arterial speeds to be input. This is used 

extensively when building cross-reference tables for the emission factors mentioned previously. 

The most accurate and thorough MOBILE6 speed input method is to input speeds via two speed 

tables (one for each facility-type) which contain the fraction of VMT for each hour of the day 

that occurs in 14 speed-bins: 0-2.5mph, 2.5-7.5mph...up to >62.5 mph. Speeds that occur during 

the peak hours would be slower than the off peak, for example MOBILE6 does contain national 

average default speeds that are useful for comparison purposes. 

NIRPC uses the latter, more thorough method of inputting speeds. The travel model data is used 

for speed calculations. Each link of roadway has a speed calculated using the formulas shown 

below. The link volume, length and calculated speed are used to determine the VMT fraction to 

place into the proper speed bin in the speed tables. 

The BPR (Bureau of Public Roads) Formula is used as follows: 

Amtime=length/ (posted speed*1.1)*60*(1+0.15*(volume/ (2.55*capacity per lane*lanes)) ^4) 

Pmtime=length/ (posted speed*1.1)*60*(1+0.15*(volume/ (2.84*capacity per lane*lanes)) ^4) 

Optime=length/ (posted speed*1.1)*60*(1+0.15*(volume/ (12*capacity per lane*lanes)) ^4). 

speed=length*60/xxtime 

Socioeconomic data

Travel demand models contain hundreds of Travel Analysis Zones (TAZs) that have zonespecific information regarding population, employment, destinations and expected growth, 

among other things. This data is commonly referred to as the “socioeconomic data”. This data 

is updated most accurately when new census data comes out. This model was updated in 2003 

based on 2000 census data. The traffic analyses of future years are then based on growth 

projections. These growth projects are then put into the TAZs where the growth (or decline) is 

expected to occur. 

5.4 Analysis Years

The travel demand model also contains the road network, thus, the information is time specific. 

NIRPC has modeled the years 2005, 2010 and 2020. Each future analysis year model scenario 

contains the road network NIRPC expects to exist at the beginning of that year with the 
34

accompanying expected socioeconomic growth projections. 

5.5 Emission Estimations

Table 5.1 outlines the on-road emissions estimates for Lake and Porter counties for the years 

2005, 2010 and 2020. 

Table 5.1 

Emission Estimates for On-Road Mobile Sources 

2005 2010 2020 

VMT (1,000 miles/day) 18,628,125 17,406,167 20,633,938

PM2.5 (tons/year) 229.39 159.16 114.31

NOx (tons/year) 14,095.55 8,459.90 3,002.86

5.6 Motor Vehicle Emission Budget

Table 5.2 contains the motor vehicle emissions budgets for Lake and Porter counties for the 

years 2010 and 2020. 

Table 5.2 

Motor Vehicle Emission Budgets 

Year 2010 2020 

PM2.5 

(tons/yr) 167.12 125.74 

NOx (tons/yr) 8,882.90 3,303.15 

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

mobile source sulfur dioxide (SO2) emissions to be a significant contributor to fine particles for 

this nonattainment area, as mobile source SO2 emissions constitutes less than one percent (<1%) 

of the area’s total anthropogenic SO2 emissions. 

These Budgets include the emission estimates calculated for 2010 and 2020. The emission 

estimates are derived from the NIRPC travel demand model and MOBILE6 as described above. 

Through the interagency consultation process, it was determined that an interim Budget for the 

year 2010, in addition to the Budget for the year 2020, would be appropriate. A reasonable 

margin of safety has been applied to the 2010 and 2020 Budgets in the amount of 5% and 10% 

respectively. 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 

emissions calculation methodology and latest planning assumptions were determined through the 

interagency consultation process described in the Transportation Conformity Memorandum of 

Understanding (MOU) for NIRPC. 

 

6.0 CONTROL MEASURES AND REGULATIONS
35

This section provides specific information on the control measures implemented in Lake and 

Porter counties, including CAAA requirements and additional federal, state or local measures 

implemented beyond CAAA requirements. 

6.1 Reasonably Available Control Technology (RACT)

As required by Section 172 of the CAAA, Indiana in the mid-1990s 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 Best Available Control Technology-New Facilities 

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 Operations 

326 IAC 8-6 Organic Solvent Emission Limitations 

Additional rules specifically applicable to Lake and Porter counties are summarized in Section 

6.2. 

Since Lake and Porter counties attained the annual standard for fine particles prior to an 

Attainment 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. However, it should be noted that the majority of major sources for NOx within Lake and 

Porter counties are subject to the NOx SIP Call, thereby meeting RACT requirements for NOx. 

Therefore, any reductions to be gained through the applicability of NOx RACT for Lake and 

Porter counties would be negligible. 

6.2 Implementation of Past SIP Revisions

Lake and Porter counties were previously nonattainment under the 1-hour ozone standard. The 

area met all of its 1-hour SIP obligations, including an EPA-approved attainment demonstration. 

All of the control measures outlined within the Post-1999 (2002, 2005, and 2007) Rate of 

Progress plans have been fully implemented. The area was also designated nonattainment for 

ozone under the 8-hour standard in 2004. Since that time, the area has attained the 8-hour ozone 

standard and a redesignation request is pending approval with U.S. EPA. Therefore, no further 

SIP revisions are required. 

The following outlines the measures implemented in association with previous SIP submittals 

that have resulted in permanent and enforceable emission reductions in Lake and Porter counties: 

Fifteen Percent Rate of Progress (ROP) Plan
36

Indiana’s final 15% ROP plan was approved by U.S. EPA on July 18, 1997. The measures 

include a mix of point, area, and mobile source control measures: 

1. Enhanced vehicle inspection and maintenance program 

Regulatory Basis: 326 IAC 13-1.1 

Implementation Status: Control remains in place. 

2. Stage II Vapor Recovery 

Regulatory Basis: 326 IAC 8-11-2 

Implementation Status: Control remains in place. 

3. Reformulated gasoline program 

Regulatory Basis: CAAA-Federal Control Program 

Implementation Status: Control remains in place. 

4. National Volatile Organic Compound Emission Standards for Architectural Coatings Rule 

Regulatory Basis: 40 CFR Part 59 

Implementation Status: Control remains in place. 

5. Residential opening burning ban 

Regulatory Basis: 326 IAC 4-1 

Implementation Status: Control remains in place for all incorporated areas. 

6. Non-CTG RACT 

Regulatory Basis: 326 IAC 8 

Implementation Status: Control remains in place. 

1999 Nine Percent Rate of Progress (ROP) Plan

Indiana’s final 1999 nine percent ROP plan was approved by U.S. EPA on January 26, 2000. 

The reductions included a variety of state and federal measures that affected various industrial 

and area sources, such as steel mills, small engines (e.g. lawnmowers), gasoline reformulation, 

and personal solvent usage. The measures included the following: 

1. The National Emission Standards for Benzene from Coke Oven By-Product Recovery Plants 
37

Regulatory Basis: 40 CFR 61 Subpart L 

Implementation Status: Control remains in place. 

2. National Emission Standards for Coke Oven Batteries 

Regulatory Basis: 40 CFR 63 Subpart L 

Implementation Status: Control remains in place. 

3. Federal Phase I Reformulated Gasoline on Small Non-road Engines 

Regulatory Basis: Clean Air Act Amendments of 1990; Section 211 of the Clean Air Act 

Implementation Status: Control remains in place. 

4. Federal Controls on Small Spark-ignited Engines 

Regulatory Basis: Court-ordered standards for small spark-ignited engines; 40CFR Part 

90 

Implementation Status: Control remains in place. 

5. Commercial/Consumer Solvent Reformulation Rule 

Regulatory Basis: Clean Air Act Amendments of 1990; Federal Rule 60 FR 15264 

Implementation Status: Control remains in place. 

6. Volatile Organic Liquid Storage RACT 

Regulatory Basis: 326 IAC 8-9 

Implementation Status: Control remains in place. 

2002 Nine Percent Rate of Progress (ROP) Plan

Indiana’s 2002 nine percent ROP plan consists of several federal regulations and some measures 

specific to Indiana, including state rules and negotiated agreements. The reductions included 

measures that control the VOC emissions from steel mill sinter plans, non-road mobile sources, 

and municipal solid waste landfills. The measures included the following: 

1. Additional Reductions from Federal Controls on Small Spark-ignited Engines 

Regulatory Basis: Court-ordered standards for small spark-ignited engines; 40 CFR Part 

90 

Implementation Status: Control remains in place. 

2. Sinter Plant Rule 
38

Regulatory Basis: 326 IAC 8-13 

Implementation Status: Control remains in place. 

3. Municipal Solid Waste Landfill 

Regulatory Basis: State rule based on the federal New Source Performance Standards for 

new and existing sources (326 IAC 8-8 and 326 IAC 8-8.1) 

Implementation Status: Control remains in place. 

2005 Nine Percent Rate of Progress (ROP) Plan

Since there were surplus emission reductions from previous plans, no emission reductions were 

necessary to meet the additional 9% reduction in VOC emissions for the 2005 ROP. However, 

the plan includes a federal regulation that will further reduce the amount of VOCs emitted by 

non-road small engine sources. The measure includes the following: 

1. Further Reductions from Federal Controls on Small Spark-ignited Engines 

Regulatory Basis: Federal Standards for small spark-ignited engines; 40CFR Part 90 

Implementation Status: Control remains in place. 

2007 Six Percent Rate of Progress (ROP) Plan

Indiana’s 2007 six percent ROP plan consists of several federal regulations and some measures 

specific to Indiana, including state rules and negotiated agreements. The reductions included 

measures that control the VOC emissions from petroleum refineries, non-road mobile sources, 

volatile organic liquid storage operations, cold cleaning degreasing operations, and the 

reformulation of commercial and consumer products. The measures included the following: 

1. Further Reductions from Federal Controls on Small Spark-ignited Engines 

Regulatory Basis: Court-ordered standards for small spark-ignited engines; 40 CFR Part 

90 

Implementation Status: Control remains in place. 

2. Commercial/Consumer Solvent Reformulation Rule 

Regulatory Basis: Clean Air Act Amendments of 1990; Federal Rule 60 FR 15264 

Implementation Status: Control remains in place. 

3. Petroleum Refineries NESHAP 

Regulatory Basis: Clean Air Act Amendments of 1990 
39

Implementation Status: Control remains in place. 

4. United States Steel Agreed Order with IDEM (March 1996) 

Control Method: Halts the use of untreated water for quenching (NESHAP-Post ROP)). 

Implementation Status: Control remains in place. 

5. Volatile Organic Liquid Storage RACT 

Regulatory Basis: 326 IAC 8-9 

Implementation Status: Control remains in place. 

6. Cold Cleaners 

Regulatory Basis: 326 IAC 8-3-8 

Implementation Status: Control remains in place. 

6.3 Nitrogen Oxides (NOx) Rule

The U.S. EPA NOx SIP Call required twenty-two (22) states to adopt rules that would result in 

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

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

for a reduction of approximately thirty-one percent (31%) of all NOx emissions statewide 

compared to previous uncontrolled years. Within Lake and Porter counties, most of the sources 

(almost all major sources for NOx) that would be affected by NOx RACT are subject to the NOx

SIP Call, which meets NOx RACT requirements. 

Twenty-one (21) other states have also adopted these rules. The result is that significant 

reductions have occurred within the Northwest Indiana area nonattainment area because of the 

number of affected units within the region. From Graphs 4.4 and 4.5 it can be seen that 

emissions covered by this program have been trending downward since 1999. Table 6.1, 

compiled from data taken from the U.S. EPA Clean Air Markets website, quantifies the gradual 

NOx reductions that have occurred in Indiana as a result of Title IV (Acid Rain) of the Clean Air 

Act Amendments and the NOx SIP Call Rule. This cap will stay in place through 2008, at which 

time the caps in the CAIR program will supersede it. 

Further, U.S. EPA has recently published Phase II of the NOx SIP Call that establishes a budget 

for large (greater than 1 ton per day emissions) stationary internal combustion engines. This rule 

will decrease emissions statewide from natural gas compressor stations by 4,263 tons during the 

ozone season. This rule became effective February 26, 2006. Implementation of this rule began 

May 1, 2007. 

TABLE 6.1 

Trends in Annual EGU NOx Emissions Statewide in Indiana 

STATEWIDE EGU NOx TRENDS 
40

Year NOx Emissions, tons / annual 

1999 347,217 

2000 334,522 

2001 315,420 

2002 281,146 

2003 260,980 

2004 224,311 

2005 207,982 

2006 202,728 

Budget 2009-2014 108,935 

Budget 2015 and later 90,779 

6.4 Measures Beyond Clean Air Act SIP Requirements

Reductions in fine particle and its precursor emissions have occurred, or are anticipated to occur, as 

a result of federal programs. These additional control measures include: 

Air Toxics Standards for Coke Ovens: Pushing, Quenching and Battery Stacks

In February 2003, EPA issued a final emissions standard to control air toxic emissions from coke 

oven processes known as pushing, quenching, and from battery stacks. Earlier requirements 

control air emissions from other points at a coke oven battery. 

When fully implemented, the February 2003 standards are expected to reduce air toxic emissions 

from these operations by nearly 300 tons per year. 

On October 4, 2004, the Environmental Protection Agency (EPA) issued final amendments to 

the national standards that reduce toxic air emissions from processes known as pushing and 

quenching, and from battery stacks on coke oven batteries. There are three sources in Lake and 

Porter counties affected by this standard. Coke oven batteries convert coal to coke which is used 

to produce iron at steel mills and foundries. These additional amendments reduced particulate 

matter emissions, as well as additional air toxic emissions. 

NESHAP for Iron and Steel Plants

On July 6, 2006 the U.S. EPA issued final amendments to the current rule that limits emissions 

of toxic air pollutants from integrated iron and steel manufacturing facilities. 

Integrated iron and steel manufacturing facilities convert iron ore to iron and refine the iron to 

produce steel. U.S. EPA established air toxics standards for these facilities in 2003. The U.S. 

EPA expects the standards to reduce toxic air emissions from the 17 existing plants, four of 

which are located in Lake and Porter counties, by about 67 tons per year and to reduce 

particulate matter emissions by about 5,800 tons per year. 

Tier 2 Vehicle Standards

Federal Tier 2 vehicle standards will require all passenger vehicles in a manufacturer’s fleet, 
41

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

grams of NOx per mile. Implementation began in 2004, and was completely phased-in in 2007. 

The Tier 2 standards also cover passenger vehicles over 8,500 pounds gross vehicle weight 

rating (the larger pickup trucks and SUVs), which are not covered by the current Tier 1 

regulations. For these vehicles, the standards will be phased in beginning in 2008, with full 

compliance in 2009. The new standards require vehicles to be 77% to 95% cleaner than those on 

the road today. The Tier 2 standards also reduced the sulfur content of gasoline to 30 ppm 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 Standards

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

and diesel highway vehicles began to take effect in 2004. A second phase of standards and 

testing procedures, implemented in 2007, will reduce fine particle emissions from heavy-duty 

highway engines, and will also reduce 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 particulate matter (PM) emissions and a 95% reduction in NOx emissions for 

these new engines using low sulfur diesel, compared to existing engines using higher-content 

sulfur diesel. 

Large Non-road Diesel Engines Standards

In May 2004, U.S. EPA promulgated new rules for large non-road diesel engines, such as those 

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

2014. The non-road diesel rules also reduce the allowable sulfur in non-road diesel fuel by over 

99%. Non-road diesel fuel currently averages approximately 3,400 ppm sulfur. This rule limited 

non-road diesel sulfur content to 500 ppm in 2006 and 15 ppm in 2010. The combined engine 

and fuel rules would reduce NOx and PM emissions from large non-road diesel engines by over 

90%, compared to current non-road engines using higher-content sulfur diesel. 

Nonroad Spark-ignition Engines and Recreational Engines Standard

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

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

sold in the United States and imported after 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 large spark-ignition engines contribute to ozone formation and ambient CO and PM levels in 

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

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

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

exhaust emission standard was phased-in by 50% and for model year 2007 and later, at 100%. 

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

of pleasure crafts. Recreational marine engines contribute to ozone formation and PM levels, 
42

especially surrounding marinas. Depending on the size of the engine, the standard began 

phasing-in in 2006. 

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

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

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

ozone, CO and fine PM. 

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

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

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

rules. 

Clean Air Interstate Rule (CAIR)

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

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

Revisions to the NOx SIP Call”, referred to as CAIR. This rule established the requirement for 

States to adopt rules limiting the emission of NOx and SO2 and a model rule for the states to use 

in developing their rules. The purpose of CAIR is to reduce interstate transport of precursors to 

fine particles and ozone. 

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

combustion turbines, a generator with nameplate capacity of more than 25MWe producing 

electricity for sale and (2) for 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 one-third of the unit’s 

potential electric output capacity or 219,000 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. 

The 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 its state rule in 2006 based on the federal 

rule. IDEM’s rule includes an annual and seasonal NOx trading program, and an annual SO2

trading program. This rule requires compliance beginning in 2009. 

6.5 Controls to Remain in Effect

Indiana 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 fine particles, 

SO2 or NOx sources as required for maintenance of the fine particles standard in Lake and Porter 

counties. 
43

Indiana, through IDEM’s Office of Air Quality and its Office of Enforcement, has the legal 

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

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

emission of fine particles and its precursors in Lake and Porter counties. 

6.6 New Source Review Provisions

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

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

Deterioration (PSD) permitting program in 326 IAC 2-2. 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 facility that is not listed in the 2005 emission inventory, or for which emission reduction 

credit through closing was taken in demonstrating attainment, will not be allowed to construct, 

reopen, modify, or reconstruct without meeting all applicable permit rule requirement. The 

review process will be identical to that used for new sources. Once the area is redesignated, 

OAQ will implement NSR for major sources through the PSD program, which requires an air 

quality analysis to evaluate whether the new source will threaten the NAAQS.
44

7.0 MODELING 

Although U.S. EPA’s redesignation guidance does not require modeling for fine particle 

nonattainment areas seeking redesignation, modeling has been performed covering the 

Northwest Indiana area to determine the effect of national emission control strategies on fine 

particle levels. This modeling analysis determined that Lake and Porter counties in Northwest 

Indiana are significantly impacted by regional transport of particulate matter and its precursors, 

and regional SO2 and NOx reductions are an effective way to continue to attain the annual fine 

particles standard in this area. Furthermore, source apportionment modeling for culpability 

analysis shows that Lake and Porter counties do not significantly impact current fine particle 

nonattainment areas in surrounding states. Future year modeled annual fine particle 

concentrations in Lake and Porter counties are expected to be reduced by 7% to 15% from 

baseline design values thereby, maintaining the current attainment status of the area. A summary 

of the modeling analysis is listed below. 

7.1 Summary of Modeling Results to Support Federal Rulemakings

LADCO Round 5 Modeling for the Clean Air Interstate Rule (CAIR)

The Lake Michigan Air Directors Consortium (LADCO) conducted modeling to determine the 

impact of CAIR in the Midwest. LADCO’s modeling used the Comprehensive Air Quality 

Model with extensions (CAMx) applied to the year 2005 meteorology, as processed by 

Mesoscale Model (MM5). Emissions input into the CAMx model included sulfur dioxide, 

nitrogen oxides, volatile organic compounds, ammonia and direct PM2.5 for 2005. The modeling 

was based on 2003 through 2006 design values. Future year modeling for 2009, 2012, and 2018 

was conducted and the future year design values were determined, as shown below in Table 7.1. 

 

Table 7.1 

LADCO’s Round 5 Modeling Annual PM2.5 Results – CAIR 

Monitor ID 

Monitor 

Name County 

Design 

Value 

2003-2006 

Basecase 

with CAIR - 

2009 

Basecase 

with CAIR – 

2012 

Basecase 

with CAIR 

– 

2018 

(ug/m3) (ug/m3) (ug/m3) (ug/m3)

180890006 East Chicago Lake 14.3 13.1 13.7 13.5 

180890027 Highland Lake 13.8 12.3 13.0 12.7 

180891003 Gary Lake 14 12.4 13.4 13.4 

180892004 Hammond - Purdue Lake 14.1 12.8 13.4 13.2 

180892010 Hammond - Robertsdale Lake 13.9 12.6 13.1 12.9 

181270020 Dunes Natl. Lakeshore Porter 12.6 11.2 12.0 11.9 

181270024 Ogden Dunes Porter 13.1 11.6 12.5 12.5 

Results of the LADCO CAIR modeling show that Lake and Porter counties will continue to 

attain the annual fine particles NAAQS of 15 μg/m3

. 

7.2 Speciated Modeled Attainment Test/Particulate Source Apportionment Analysis

LADCO Round 4 Modeling

Speciated Modeled Attainment Test (SMAT) is the attainment test for annual fine particles. 
45

Speciated data or the sulfates, nitrates, ammonium, organic carbon, elemental carbon, particle 

bound water, “other” primary inorganic particulate matter and passively collected mass 

associated with fine particle mass, is calculated to determine the future year annual fine particle 

concentrations. SMAT results from LADCO’s Round 4 modeling for the years 2009, 2012, and 

2018 are listed below. Each percent represents a positive reduction compared to 2002 speciation 

data. 

Table 7.2 

LADCO’s Round 4 PSAT/SMAT Modeling Results in Percent Reduction 

Lake County 

2009 2012 2018 

Sulfates 9% - 10% 10% - 12% 7% - 10% 

Nitrates 5% - 6% 6% - 11% 11% - 17% 

Organic Carbon 2% - 3% 2% - 4% 3% - 6% 

Table 7.3 

LADCO’s Round 4 PSAT/SMAT Modeling Results in Percent Reduction 

Porter County 

2009 2012 2018 

Sulfates 9% 9% - 13% 6% - 9% 

Nitrates 6% 6% - 11% 12% - 17% 

Organic Carbon 3% 3% 3% 

Particulate source apportionment (PSAT) shows the breakdown of the modeled fine particle 

impacts by the different constituents of fine particles, the emissions sectors from which fine 

particles or their precursors are emitted and by geographic regions. Figure 7.1 shows the PSAT 

modeled results for Chicago for 2012. 
46

Figure 7.1 

PM2.5 Source Apportionment Results for Chicago for 2012 

The biggest contribution among the constituents of fine particles in the Chicago area is sulfates 

(SO4). The biggest contribution among emission sectors was area sources. The fine particle 

contribution from Indiana’s portion of the Chicago nonattainment area is less than 1.0 ug/m3. 

The Round 4 results provide a good indication of the effects of emissions reductions from 

national emission control measures. 

7.3 Summary of Modeled Results

LADCO modeling for future year design values has consistently shown that existing national 

emission control measures will continue to keep Lake and Porter counties in attainment of the 

annual fine particles NAAQS. In addition, U.S. EPA modeling in support for the Clean Air 

Interstate Rule has shown that future year design values for the Northwest Indiana counties will 

continue to attain the annual fine particle standard with modeled values below 15.0 ug/m3

. 

Future national and local emission control strategies will ensure that Lake and Porter counties’ 

annual fine particle attainment area will be maintained with an increasing margin of safety over 

time. 
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8.0 CORRECTIVE ACTIONS

8.1 Commitment to Revise Plan

As noted in Section 4.6 above, Indiana hereby commits to review its Maintenance Plan eight (8) 

years after redesignation, as required by Section 175A of the CAAA.

8.2 Commitment for Contingency Measures

Indiana 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, Indiana will take 

action to reverse the noted trend, prior to a violation of the standard occurring. 

Indiana hereby commits to adopt and expeditiously implement necessary corrective actions in 

the following circumstance: 

Action Level Response

An Action Level Response shall be prompted whenever a violation of the standard three 

(3)-year average of 15.1 μg/m3occurs. In the event that the Action Level is triggered and 

is not found to be due to an exceptional event, malfunction, or noncompliance with a 

permit condition or rule requirement, IDEM will determine additional control measures 

needed to assure future attainment of 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 (18) months from the close of the monitoring season that prompted the Action 

Level. 

Control Measure Selection and Implementation

Adoption of any additional control measures is subject to the necessary administrative 

and legal process. 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, Indiana 

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 
48

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. Indiana 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 emission offsets for new and modified major sources. 

3) Require NOx or SO2 emission offsets for new and modified minor sources. 

4) Increase the ratio of emission offsets required for new sources. 

5) Require NOx or SO2 controls on new minor sources (less than 100 tons). 

7) Wood stove change-out 

8) Idle Restrictions 

9) Broader geographic applicability of existing measures. 

10) One or more transportation control measures sufficient to achieve at least a half a percent 

(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 

affects state and local governments deemed appropriate. 

 

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
49

In accordance with Section 100 (a) (2) of the CAAA, Indiana published notification for a public 

hearing and solicitation for public comments concerning the draft Redesignation Petition and 

Maintenance Plan in the Gary Post Tribune, Chesterton Tribune and The Indianapolis Star, 

Indianapolis, Indiana on or before January 28, 2008. 

A public hearing to receive comments on the redesignation request was held on February 27, 

2008, in the Multi-Purpose Room #C125, at Ivy Tech Community College – Gary Campus, 

Gary, Indiana and a number of comments were received. The public comment period closed on 

March 11, 2008. Appendix G includes a copy of the public notice, certifications of publication, 

he transcript from the public hearing, public hearing attendance record, copies of all written 

comments received and a summary of comments received that includes IDEM’s responses, as 

applicable. 

10.0 CONCLUSIONS 

Lake and Porter counties have attained the annual NAAQS for fine particles and do not 

significantly contribute to violations outside its portion of the nonattainment area. This petition 

demonstrates that Lake and Porter counties have complied with the applicable provisions of the 

1990 Amendments to the Clean Air Act regarding redesignation of nonattainment areas of fine 

particles. IDEM has prepared a State Implementation and Maintenance Plan that meets the 

requirement of Section 110 (a)(1) of the 1990 Clean Air Act. 

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 Phase II NOx SIP Call and CAIR will ensure continued compliance 

(maintenance) with the standard. Indiana has also demonstrated that Lake and Porter counties 

should not have been designated as nonattainment of the annual fine particles standard and 

redesignating the area to attainment will not adversely affect any downwind area’s ability to 

attain the standard. Additionally, Indiana has ensured that all CAA requirements necessary to 

support redesignation have been met. 

In addition to the corrective actions (should they be necessary) outlined in this submittal, the 

State of Indiana continues to participate in the regional air quality planning efforts sponsored by 

LADCO. The current goal of the planning process is to establish a regional control strategy that 

provides for attainment of the ozone and fine particles standards and regional haze requirements, 

throughout the states of Illinois, Indiana, Michigan, Ohio and Wisconsin. Along with the other 

LADCO states, the state of Indiana is considering the implementation of local and statewide 

emission control measures, where photochemical modeling and culpability analysis demonstrates 

a clear need and cost-effectiveness analyses justify the implementation of such measures. 

Furthermore, because this area is subject to significant transport of pollutants, significant 

regional NOx and SO2 reductions will ensure continued compliance (maintenance) with the 

standards with an increasing margin of safety. Based on this presentation, Lake and Porter 

counties meet the requirements for redesignation under the CAA (Section 107 (d)(3)) and U.S. 

EPA guidance. 

Consistent with the authority granted to the U.S. EPA, the State of Indiana hereby requests that 

Lake and Porter counties be redesignated to attainment simultaneously with U.S. EPA approval 

of the Indiana State Implementation and Maintenance Plan provisions contained herein. 
50