# Maintenance Plan for the Chicago Nonattainment Area for the 1997 

# PM2.s National AmbientAir Quality Standards (Revised)

AQPSTR 11-07



# August 17, 2011


# Illii1ois Environtnental Protection Agency 1021 

# N

# ortl1 GrandAvenue East Springfield, Illinois 62794-9276

### TABLE OF CONTENTS Page LIST OFTABLES
. iii 

### LIST OFFIGURES
. IV 

### EXECUTIVE SUMMARY
. 5 

### 1.0 INTRODUCTION
. 6 1.1 Regulatory Background 6 1.2 Status ofAir Quality
. 8 

### 2.0 REDESIGNATIONAND MAINTENANCE PLANREQUIREMENTS 9 3.0 PM2.s MONITORING 11 3.1 Monitored Design Values 11 3.2 QualityAssurance 12 3.3 Continued Monitoring 12 4.0 

### EMISSIONS INVENTORY. 14 4.1 Attainment Year Inventory 

### 14 4.2 Air Quality Improvements and Emissions Controls 15 4.3 Emissions Projections. 16 4.4 Demonstration ofMaintenance 16 4.5 Provisions for Future Updates 18 

### 5.0 CONTROLMEASURES AND REGULATIONS 19 5.1 Contro

### 1Measures 

### 19 5.2 Reasonable FurtherProgress (RFP) and Reasonably Available Control Technology (RACT)
. 20 5.3 Controls to Remain in Effect
. 20 5.4 Provisions for PermittingNew orModified Emissions Sources 21 5.5 Transportation Conformity 21 

### 6.0 CONTINGENCYMEASURES 23 6.1 ContingencyMeasures 23 6.2 Commitmentto Revise Plan 25 6.3 Public Participation
. 25 6.4 Legal Authorityto Implement and Enforce 26 

### 7.0 CONCLUSIONS 27TABLE OF CONTENTS (Continued)

APPENDIX A Summary ofAmbient AirMonitoring Data (2007-2009) APPENDIX B Transportation Conformity

11 28 30LIST OF TABLES Page Table 4.1 2008 PM2.5, NOx and S02 Emissions
. 14 Table4.2 2002 PM2.5, NOx and S02 Emissions
. 15 Table 4.3 2015 PM2.5, NOx and S02 Emissions. 16 Table 4.4 2020 PM2.5, NOx and S02 Emissions
. 17 Table 4.5 2025 PM2.5, NOx and S02 Emissions. 17 Table4.6 Comparison of2008, 2015, 2020 and 2025 Emissions 17 Table 5.1 Proposed 2008 and 2025 Motor Vehicle Emissions Budgets Chicago Nonattainment Area PM2

_ 5 Maintenance Plan. 22 Table 6.1 Contingency Plan for the Chicago PM25 Nonattainment Area 24

iiiFigure 1.1 Figure3.1 Figure3.2 LIST OFFIGURES Chicago PM2.5 NonattainmentArea. PM2.5 Monitors in the Chicago Nonattainment Area
. Comparison ofPM25 Design Values for the Chicago NonattainmentArea Between 2000-2002 and 2007-2009

IV Page 7 11
13**EXECUTIVESU~Y** This document describes Illinois' Maintenance Plan for the Illinois portion ofthe Chicago fine particulate matter (PM2.5) nonattainment area (NAA), hereafter referred to as the ChicagoNAA. An approved Maintenance Plan is required before an area can be redesignated from nonattainmentto attainment ofa National AmbientAir Quality Standard (NAAQS). This document provides technical information required to support a requestto redesignate the Chicago NAA to attainment ofthe 1997 annual PM2.5 NAAQS. This revision incorporates motor vehicle emissions estimates developed using the U.S. EPA's MOVES model. The Indiana Department ofEnvironmental Management (IDEM), has prepared a similar plan for the Indiana portion ofthe Chicago NAA. PM25 air qualityhas improved in the Chicago area as a result ofthe implementation of State and Federal emissions control measures since the designation ofthe area as nonattainment in 2004. The air quality improvement is due to permanent and enforceable emissions control measures. The entire Chicago NAA has at leastthree years of complete, quality assured ambient air quality monitoring data for 2007-2009 that demonstrates compliance with the 1997 NAAQS. The U.S. EPA has made a determination thatthe Chicago NAA has attained the 1997 fine particle standard (40 CFR 52.74, p. 62243-62249). This Maintenance Planprovides for continued attainment ofthe 1997 PM2.s air quality standards for the Chicago nonattainment area for a period ofat least ten years after U.S. EPA has formally redesignated the areato attainment. The Plan also provides assurances that, even ifthere is a subsequent violation ofthe air quality standard, contingency measures listed in the Planwill be triggered to prevent any future occurrences. Finally, the Plan includes on-road motorvehicle emissions budgets for the years 2008 and 2025 for use in transportation conformity determinations to assure that any increases in emissions from this sector do notjeopardize continued attainment ofthe PM2.s standards during the maintenance period.

5

### 1.0 INTRODUCTION The Illinois Environmental Protection Agency (Illinois EPA) has prepared this document to describe Illinois' PM2 .s Maintenance Plan for the Chicago NAA. This Maintenance Plan is required before the area can be redesignated from nonattainment to attainment of the annual National AmbientAir Quality Standard (NAAQS) for PM2 . 5 promulgated by the U.S. Environmental Protection Agency (U.S. EPA) in 1997. The Illinois EPA intends to submit such a request to the U.S. EPA in conjunction with this Maintenance Plan. The entire Chicago nonattainment area, including Lake and Porter counties in Indiana, has at least three years ofcomplete, quality assured ambient air quality monitoring data for the most recent 3-yearperiod, 2007-2009, demonstrating attainment ofthe annual PM2 . 5 NAAQS promulgated in 1997. U.S. EPA finalized its determination that the entire Chicago NAA attains the 1997 PM2 . 5NAAQS in November 2009. This documentprovides the technical information needed to support a request to redesignate the Chicago area to attainment ofthe 1997 annual PM25 NAAQS. Section 107 ofthe Clean AirAct (CAA) establishes specific requirements to be met in order for a nonattainment area to be considered for redesignation. Before an area can be reclassified to attainment:

• U.S. EPA must make a determination that the area has attained the NAAQS based on at least three complete years ofambient monitoring data. • U.S. EPA must have approved a State Implementation Plan (SIP) for the area under Section 110 and PartD ofthe CAA. • The state must demonstrate that the improvement in air quality is due to permanent and enforceable reductions in emissions resulting from implementation ofthe SIP and other federal requirements. • The state must submit, and U.S. EPA must approve, a Maintenance Plan under Section 175(A) ofthe CAA, including provisions for contingency measures that will be implemented iffuture violations ofthe NAAQS are measured. This Maintenance Plan provides for the continued attainment ofthe annual PM2 . 5 NAAQS for the Chicago NAA for a period ofat least ten years after U.S. EPA has formally redesignated the area to attainment. The Plan also provides assurances that even ifa subsequent violation ofthe annual PM2 .s NAAQS occurs, provisions in the Plan will prevent any future occurrences through the enactment ofcontingencymeasures that would be triggered upon such occurrence. This document addresses the Maintenance Plan requirements established by the CAA and U.S. EPA, and includes additional information to support continued compliance with the PM2.s NAAQS. 1.1 Regulatory Background The CAA requires areas that fail to meetthe NAAQS for PM2 . 5 to develop SIPs to expeditiously attain and maintain the NAAQS. Historically, one-year exceedances ofthe annual PM2 . 5 NAAQS have been monitored as recently as 2007 at one monitor in Cook County, but all monitors in the NAA are now in attainment ofthe PM2 . 5NAAQS.

6The Chicago NAA, which includes all ofCook, DuPage, Kane, Lake, McHenry and Will counties, as well as portions ofGrundy and Kendall counties, was originally designated as nonattainment ofthe 1997 annual PM2.s in 2004. The Chicago areawas designated unclassifiable/attainment for the 24-hourPM2.s standard that was also promulgated in 1997, and revised in 2006. Sincethe Chicago area is not a nonattainment area for the 24- hour PM2.s NAAQS, any reference to the PM2.5NAAQS in the remainder ofthis documentrefers onlyto the annual PM2.5 standard promulgated in 1997. Figure 1.1 depicts the boundaries ofthe Chicago PM2.5NAA in Illinois. 

### Figure 1.1- Chicago PM2.5 

### Nonattainment Area Chicago PM2.5 Nonattainment Area

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7 20 MilesThe following is a list ofthe counties contained in the Chicago PM2 .5 nonattainment area:
• Cook County, IL • DuPage County, IL • Kane County, IL • Lake County, IL • McHenry County, IL • Will County, IL • Aux Sable and Goose Lake Townships in Grundy County, IL, and • Oswego Township in Kendall County, IL
As a result ofthe nonattainment designation, this area was subjectto newrequirements, including development ofan attainment strategythat would allow the area to meetthe federal PM2 .5 NAAQS by June 15, 2010. The attainment strategy recognizes the importance ofreducing both locally-generated as well as incoming (transported) PM2.s and precursoremissions. State and Federal emissions control measures have reduced primary and secondaryPM2 .s emissions both locally and regionally and have enabled the Chicago NAA to attain the PM2.s NAAQS bythe attainment deadline established bythe U.S. EPA. 1.2 Status ofAir Quality PM2 .s monitoring data for the most recent three-year period, 2007 through 2009, demonstrates that air quality has met the 1997 PM2.5 NAAQS in the Chicago NAA. Information regarding the air monitoring network and air quality monitoring data is included in Section 3.0 and Appendix A.

8

### 2.0 REDESIGNATION AND MAINTENANCE PLAN REQUIREMENTS Sections 107 and 110 ofthe CAA list a number ofrequirements that must be met by nonattainment areas priorto consideration for redesignation to attainment. One ofthose requirements is the development ofa Maintenance Plan, which describes a state's plan for maintaining the NAAQS for a minimum ten-year period after redesignation. The Illinois EPA developed this Maintenance Plan according to the guidance published by the U.S.EPA entitled "Procedures for ProcessingRequests to Redesignate Areas to Attainment" (September 4, 1992). Before a redesignation to attainment can be promulgated, U.S. EPA must:

• Determine that the NAAQS for PM2 . 5, as published in 40 CFR 50.4, has been attained. 

### PM25 monitoring data must showthat violations ofthe NAAQS are no longer occurring. This showing must rely on three consecutive years ofdata. The ambient air monitoring data must be quality assured in accordance with 40 CFR 58.10, recorded in U.S. EPA's Air Quality System (AQS) data base, and made available to the public. U.S. EPA has already finalized and published a finding that the area has, in fact, attained the NAAQS. This finding was published in the Federal Register in November 2009.

• Approve the state's plan for demonstrating attainment. The attainmentplan, which is based on air quality modeling, must contain enforceable control measures and must be submitted as a revision to the state's SIP after a public hearing.

• Determine that the improvement in air quality between the year violations occurred and the yearthat attainmentwas achieved is based on permanent and enforceable emissions reductions.

• Approve the state's Maintenance Plan. The requirements for the Maintenance Plan are discussed below.

• Determine that all otherrequirements applicable to the nonattainment area have been met. A PM2 .5Maintenance Plan provides for the continued attainment ofthe 

### PM25 NAAQS for a nonattainment area for a period ofat least ten years after U.S. EPA has formally redesignated the areato attainment. To be approvable, the state is required to have a public commentperiod and provide the opportunity for a public hearing on the Maintenance Plan priorto adoption. The Maintenance Plan must contain the following elements:

• A comprehensive "attainmentyear" emissions inventory ofprimary PM2 .5 and the precursors ofsecondary PM2.s: oxides ofnitrogen (NOx) and sulfur dioxide (S02 );

9• A projection ofthe emissions inventory forward to a year at least ten years after redesignation and a demonstration that the projected level ofemissions is sufficient to maintain attainment ofthe PM2.5 NAAQS;

• A commitmentthat, once redesignated, the state will continue to operate an appropriate monitoring networkto verify maintenance ofthe attainment status;

• A demonstration oflegal authority to implement and enforce all control measures contained in the SIP;

• Provisions for future updates ofthe inventory to enable tracking ofemissions levels, including an annual emissions statement from major sources;
• Motorvehicle emissions budgets for transportation conformity for the ten-year maintenance period;

• A commitmentto submit a revised Maintenance Plan eight years after redesignation;

• A commitmentto enact and implement additional contingency measures expeditiously in the event that future violations ofthe NAAQS occur; and

• A list ofpotential contingency measures that would be implemented in such an event. This Maintenance Plan has been prepared in accordance with the requirements specified in U.S. EPA's guidance document and additional guidance received from U.S. EPA staff. The following sections ofthis document describe howU.S. EPA's requirements have been met.

103.0 

### PM2.s MONITORING U.S. EPA's published guidance document, "Procedures for Processing Requests to Redesignate Areas to Attainment" (September 4, 1992), details specific requirements regarding the collection and use ofambient air monitoring data needed to support a redesignation request. Beforethe Chicago NAA can beredesignated, Illinois must demonstrate thatthe PM2 .5 NAAQS has been attained. PM2.s monitoring data must show that violations ofthe NAAQS are no longer occurring within the nonattainment area. This showing must rely onthree complete, consecutive calendar years ofquality assured data. Further, the air monitoring data must be quality assured in accordance with 40 CFR 58.10, recorded in U.S. EPA'sAQS data base, and made available to the public. As previously mentioned, U
.S.EPA has made a finding that the Chicago NAA has metthese requirements and is attainingthe 1997 PM2
.sNAAQS. Finally, Illinois must committo continue to operate an appropriate monitoring networkto verifythe maintenance ofthe attainment status, once the area has beenredesignated. The following subsections describe how each ofthese requirements has been addressed. 3.1 Monitored Design Values Currentlythere are 19 PM25 monitors located in the nonattainment counties in the Illinois portion ofthe Chicago nonattainment area. Figure 3.1 shows the locations ofthese monitors. Figure 3.1- PM2.5 Monitors in the Chicago Nonattainment Area

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11 Springfield .&To determine whetherthe NAAQS has been met, the annual PM2 . 5 design value has been calculated for the 3-yearperiod, 2007-2009. The current U.S. EPA method for calculatingthe annual PM2 .s design value is to average each monitor's annual average values over a 3-yearperiod and compare the calculated design values to the 15.0 microgram per.cubic meter level ofthe NAAQS. The calculated annual PM2 .s design values for the monitors in the Chicago NAA for 2007-2009 are included as Appendix A ofthis report. Figure 3.2 compares the design values for 2000-2002, when the area was initially recommended for designation as a nonattainment area, and the 2007-2009 period for monitoring stations in the Chicago region. The comparison shows that PM2 . 5 air quality has improved considerably since 2000-2002 throughout the Chicago NAA. The 2007-2009 data shows that the design values at all monitoring sites are less than the level ofthe annual PM2.s NAAQS, demonstrating that the area attains the annual PM2.s air quality standard. 3.2 QualityAssurance The Illinois EPA has quality assured all monitoring data shown in Appendix A for all sites located in Illinois in accordance with 40 CFR 58.10 and the Illinois EPA's Quality Assurance Plan, which describes Illinois EPA's standard operatingprocedures for operating the ambient monitoring network and validating the data. The Illinois EPA has recorded the monitoring data in the U.S. EPA'sAQS database, which is available to the public. 3.3 Continued Monitoring Illinois commits to continue monitoring PM2 .s levels according to a U.S. EPA approved monitoring plan, as required to ensure maintenance ofthe PM2 . 5 NAAQS. Should changes in the location ofa PM2 .5 monitorbecome necessary, the Illinois EPA will work with U.S. EPA to ensure the adequacy ofthe monitoring network. The Illinois EPA will continue to quality assure the monitoring data to meet the requirements of40 CFR 58. The Illinois EPA will continue to enter all data into AQS on a timelybasis in accordance with federal guidelines.

12Figure 3.2- PM2.5 Design Values for the Chicago NonattainmentArea Between 2000-2002 and 2007-2009
2000-2002 Design Values 2007-2009 Design Values

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### 4.0 EMISSIONS INVENTORY A redesignation request must contain a demonstration 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 emissions reductions. As described previously in Section 3.0, a three-year monitoring period is used to evaluate whether actual air quality attainmenthas been achieved. In this Section, the "'attainment year" refers to the midpoint year (2008) ofthe three-year period (2007-2009) used to demonstrate attainment. As required by U.S.EPA redesignation guidance, this request also includes a projection ofthe emissions inventory to a year at least 10 years following redesignation, a demonstration that the projected level ofemissions is sufficient to maintain the 

### PM25 NAAQS, and a commitment to provide future updates ofthe inventory to enable tracking ofemissions levels during the 1 0-year maintenance period. 4.1 Attainment Year Inventory The Illinois EPA has prepared a comprehensive emissions inventory for the Chicago 

### PM 25 nonattainment area, including point, area, and on-road and off-road mobile sources for primary PM2 .s as well as precursors ofPM2.s (NOx and S02) for the year 2008. The Illinois EPA selected 2008 emissions data to represent the "'attainment year" since it is the middle year ofthe 3-yearperiod (2007-2009) which demonstrates monitored attainment. This inventory is based on actual activity levels. Point source information was compiled from 2008 Annual Emissions Reports (AERs) submitted to the Illinois EPA byemissions sources. Area source emissions were calculated using the most recently available methodologies and emissions factors from U.S. EPA along with activity data (typically population, employment, fuel use, etc.) specific to 2008. On-road mobile source emissions were calculated using U.S. EPA's MOVES emissions model with 2008 vehicle miles traveled (VMT) data provided by the Illinois Department of Transportation (IDOT). Off-road mobile source exhaust emissions, such as those from lawn and garden equipment, agricultural equipment, and construction equipment were calculated for summer 2008 using U.S. EPA'sNONROAD emissions model. Emissions sources such as commercial marine vessels, locomotives and aircraft were not included in the NONROAD model and were calculated separately. Biogenic emissions were not included in these summaries. Table 4.1 summarizes the 2008 emissions estimates for the Chicago 

### PM 25 nonattainment area. Table4.1 2008 PM2• 5, NO:x, and S02 Emissions (tonsperyear) SourceCategory PMz.s NOx SOz Point Sources 3,859 35,939 90,706 Area.Sources* 9,189 32,318 4,109 On-Road Mobile Sources 5,100 127,951 537 Off-Road Mobile Sources 3,653 51,184 779 Total 21,800 247,391 96,130 *does not include fugitive dust emissions from construction (residential, road and other) and agricultural tilling
144.2 Air Quality Improvements and Emissions Controls The Chicago area was designated as nonattainment ofthe 1997 PM2

_ 5 NAAQS in 2004. Since that time, permanent and enforceable reductions ofprimary PM2 .s and secondary PM2

_ 5 precursor emissions have contributedto improvements in PM2.s air quality and to the attainment ofthe PM2.5 NAAQS. Some ofthese emissions reductions were due to the application oftighter federal emissions standards on motor vehicles and fuels, and some due to the requirements ofthe federal NOx SIP Call. Section 5.0 ofthis report describes these reductions in more detail, along with an explanation oftheirregulatory status. In this subsection, the 2008 attainment year emissions levels are compared to the base year 2002 emissions levels. The U.S. EPA's PM25 Emissions Inventory Guidance requires that states with PM2 . 5 nonattainment areas prepare and submit a 2002 base year inventory ofanthropogenic sources ofdirect PM2 .5and precursors ofsecondaryPM2.s emissions, namely NOx and S02. This base year inventory included emissions from point, area, on-road mobile and off-road mobile emissions. The Illinois EPA prepared and submitted this inventory in May 2006. Table 4.2 summarizes 2002 emissions bymajor source category and by pollutant for the Chicago NAA. This summaryhas been revised to incorporate emissions estimates for on-road mobile sources using U.S. EPA's MOVES model.
Table

### 4.2 2002 PM2.s NOx, and S02Emissions (tons peryear) Source Category PM2.s NOx so2 Point Sources 2,757 54,050 121,598 Area Sources 22,356 32,325 3,290 On-Road Mobile Sources 6,573 187,632 4,472 Off-Road Mobile Sources 4,834 87,426 3,743 Total 36,520 361,433 133,103 Comparingthe 2002 inventoryto that for 2008 indicates that the total direct PM2.5 emissions in the Chicago area were reduced by 14,720 tons peryear. NOx emissions in the Chicago area decreased significantly, by 114,042 tons per year, during the same time period. These reductions were primarily from on-road and off-road mobile sources. S02 emissions in the Chicago area decreased by 36,973 tons peryear, due largely to reductions from point sources. These sizeable emissions reductions in direct PM2 .s emissions and secondary PM2.s precursor emissions, as well as corresponding reductions in upwind areas in Illinois and othernearby states resulted in a substantial improvement in PM2

_ 5 air quality in the Chicago area, ultimately resulting in attainment ofthe 1997 PM2.s NAAQS.

154.3 Emissions Projections A Maintenance Plan must contain a demonstration that the level ofemissions projected for the ten-year period following redesignation are sufficient to maintain the NAAQS. Accordingly, Illinois EPA has projected PM2.s, NOx, and S02emissions for the Chicago NAA for 2025. Illinois EPA has also projected emissions to 2015 and 2020 to represent midpoint years during the maintenance period. Emissions for these projection years are compared to emissions levels in 2008 to determine ifemissions are sufficient to maintain the NAAQS during this period. Chicago areapoint and area source emissions for 2015, 2020, and 2025 were estimated using the 2008 base year inventory and growth factors appropriate for each source category. Off-road emissions projections were developed using the growth factors contained in U.S. EPA's NONROAD model. On-road motorvehicle emissions were estimated using U.S. EPA's MOVES motor vehicle emissions model. The figures assume the continued use ofreformulated gasoline, the continued phase-in ofthe Tier 2 motorvehicle emissions standards, and operation ofan enhanced vehicle inspection and maintenance program. Total vehicle miles oftravel (VMT) for 2015, 2020 and 2025 were assumed to increase at a rate of 1.5 percent peryear from 2008. Tables 4.3, 4.4 and 4.5 include the direct NOx, PM2.s and S02 emissions estimates for the years 2015, 2020 and 2025 respectively, for the Chicago nonattainment area. Table4.3 2015 PM2s NOx,·and S02 Emissions (tons peryear) Source Category PM2.s NOx so2 Point Sources 4,169 27,082 58,092 Area Sources 9,676 32,997 4,266 On-Road Mobile Sources 3,071 68,491 504 Off-RoadMobile Sources 2,995 35,927 866 Total 19,911 164,497 63,727

4.4 Demonstration ofMaintenance Table 4.6 provides a comparison ofemissions for the years 2008, 2015, 2020, and 2025. The table demonstrates that the level ofemissions projected through the maintenance period are less than emissions estimated for the attainment year and are, therefore, sufficientto maintain the PM2.s NAAQS. As shown in the table, both S02and NOx emissions within the nonattainment area are expected to decrease significantlybetween 2008 and 2025 with PM2 .5 decreasing slightly. Projected emissions ofthose pollutants for the mid-point years of2015 and 2020, are also less than theirrespective emissions levels in 2008. Based onthese emissions trends it is expected that air quality will continue to meetthe 

### PM 25 NAAQS throughout the maintenance period.

16PM2.s NOx 802 Table 4.4 2020 PM2 s NOx, and S02Emissions (tons peryear) oJ' Source Category PM2.s NOx so2 Point Sources 4,391 28,500 53,452 Area Sources 10,009 33,277 4,332 On-Road Mobile Sources 2,119 40,599 477 Off-Road Mobile Sources 2,398 28,271 919 Total 18,918 130,648 59,180

Table 4.5 2025 PM2.s, NOx, and S02Emissions (tons peryear) Source Category PM2.s NOx S02 Point Sources 4,604 29,638 56,310 Area Sources 10,377 33,687 4,407 On-Road Mobile Sources 2,067 38,456 488 Off-Road Mobile Sources 2,267 27,173 1,215 Total 19,316 128,954 62,420

Table 4.6 Comparison of2008, 2015, 2020 and 2025 Emissions (Emissions stated in tons per year) 2008 2015 2020 2025 Decrease Decrease (2008-2015) (2008-2020) 21,800 19,911 18,918 19,316 1,889 2,882 247,391 164,497 130,648 128,954 82,894 116,743

96,130 63,727 59,180 62,420 32,403 36,950 Decrease (2008-2025) 2,484 118,437 33,710

In addition to the overall emissions reductions projected to occurwithin the nonattainment area, significant reductions ofstatewide NOx and S02 emissions resulting from implementation ofIllinois' multi-pollutant standards affecting electric utilities during the maintenance period, will also help to ensure continued attainment ofthe 

### PM25 NAAQS. It should also be noted that the emissions projections included here do not reflectthe reductions expected from a range ofmeasures being implemented to reduce diesel emissions in the Chicago NAA. These measures have been funded through sources such as the:

• U.S. EPA'sMidwest Clean Diesel Initiative • Congestion Mitigation and Air Quality Improvement (CMAQ) Program • Diesel Emissions Reduction Act (DERA)
17• American Recovery and Reinvestment Act of2009 • Various Supplemental Environmental Projects These projects include the installation ofparticulate filters, diesel oxidation catalysts, closed-crankcase ventilation systems, and direct-fired heaters on school and transit buses, and municipally-owned utility vehicles, repowering diesel locomotive engines with generator sets, upgrading diesel construction engines with engines meeting more stringent emissions standards, and installing auxiliary powerunits on over-the-road trucks to reduce idling. We anticipate DERA and CMAQ funding to continue to support additional diesel emissions reduction projects in the near future. 4.5 Provisions for Future Updates As required by Section 175A(b) ofthe CAA, Illinois commits to submitto U.S. EPA, eight years afterredesignation, a revised version ofthis Maintenance Plan. The revision will contain Illinois' plan for maintaining the PM2.s NAAQS for ten years beyond the initial maintenance period.

18

### 5.0 CONTROL MEASURES AND REGULATIONS This section provides specific information on the control measures implemented in the Chicago NAA. These include CAA requirements, and other state and federal measures. These control measures have been fully promulgated, and will provide emissions reductions in future years. Illinois EPA commits to keep these measures in effect after redesignation, orto maintain equivalent emissions levels using alternate measures. Illinois' SIP contains acceptable provisions to provide for preconstruction review ofnew emissions sources. Afterredesignation to attainment, Prevention ofSignificant Deterioration (PSD) requirements will apply to the construction ofnew major sources and to significant modifications ofexisting sources. Illinois has accepted delegation from U.S. EPA ofthis program. Illinois further commits to continue to require that all future regional transportation plans for the Chicago area conform to the SIP. 5.1 Control Measures A variety ofcontrol measures are in place that reduce emissions ofdirect PM2.5, NOx and S02, and have contributed to the attainment ofthe annual fine particle standard. The emissions reduction measures for demonstrating attainment ofthe 

### PM25 standard are as follows:

• NOx SIP Call • New Source Performance Standards (NSPS) and National Emissions Standards for Hazardous AirPollutants (NESHAPS)/Maximum Achievable Control Technology (MACT) Standards • VOM Solvent Categories: Aerosol Coatings, Architectural and Industrial Maintenance (AIM) Coatings, Consumer Solvents • Vehicle Inspection & Maintenance Program • Reformulated Gasoline • Tier 2 Motor Vehicle Emissions Standards and Gasoline Sulfur Control Requirements • On-Highway Heavy-DutyEngine and Vehicle Standards and HighwayDiesel Fuel Sulfur Control Requirements • Federal Emissions Standards for Off-Road Equipment (e.g., Nonroad Diesel Engine Rule, Evaporative Large Spark Ignition and Recreational Vehicle Standards) incorporated into NONROAD Model • Tier 4Nonroad Diesel Engine Standards and Diesel Fuel SulfurContent Restrictions • Marine Compression-IgnitionEngine Standards and Locomotive Engine Standards • ConsentDecrees (CITGO and ExxonMobil)

195.2 Reasonable FurtherProgress (RFP) and Reasonably Available Control Technology (RACT) Since U.S. EPA has published an attainment finding for the Chicago area for the 1997 

### PM 25standard, the requirements for Illinois to submit an attainment demonstration, RACM, RFP, contingency measures, and any otherplanning SIP's related to attainment are suspended as long asthe area continues to attain the 1997 

### PM25NAAQS. 5.3 Controls to Remain in Effect Illinois will maintain all ofthe control measures listed in this Section to ensure maintenance ofthe annual PM2 . 5 NAAQS. Any revisions to the control measures included as part ofthe Maintenance Plan will be submitted as a SIP revision to U.S. EPA for approval, and will be accompanied by a showing that such changes will not interfere with maintenance ofthe NAAQS. In addition, clean construction standards are in place as part ofCook County Ordinance No. 09-0-36, 5-19-2009 (Article IX, Section 30-952) that mandates that contractors must use Ultra Low Sulfur Diesel fuel in diesel vehicles, nonroad vehicles, and stationary generators for Cook County government projects exceeding $2 million. Furthermore, by the start of2014, any primary contractor working on a construction project in Cook County shall be required to meet a PM emission reduction ofat least 85% from uncontrolled for any heavy duty diesel vehicle or diesel nonroad vehicle. This level of control ofdiesel vehicles must be met by subcontractors bythe start of2016. This is not included as a contingency measure, but is further evidence ofcurrent and future PM emissions reductions in the heart ofthe urban area. The O'Hare Airport Modernization Program already has in place an Ultra Low Sulfur Diesel fuel requirement for all off-road diesel powered vehicles and equipment (both mobile and stationary) that are utilized on-site. (O'Hare Modernization Project Site Preparation, ProjectNo. OH6126.200.50.023, specification no. 35491) This requirement is in place for the remainder ofthe project. The Illinois EPA has the necessary resources to enforce any violations ofits rules or permit provisions. Afterredesignation, it intends to continue enforcing all rules that relate to the emissions ofprimary PM2.s and precursors to secondaryPM2 .5in the Chicago nonattainment area. 5.4 Provisions for Permitting New orModified Emissions Sources Illinois has longstanding and fully implemented programs for the review ofnew major sources and significant modifications ofexisting sources. The PSD program, which includes requirements for Best Available Control Technology (BACT) on majornew sources or significant modifications ofexisting sources, will be applicable in the Chicago

20area once the area has been redesignated to attainment. Illinois has been delegated full authority to implementthe PSD program by U.S. EPA. 5.5 Transportation Conformity The purpose ofthis section is to describe and establish the Chicago nonattainment area motor vehicle emissions budgets associated with the PM2.5 Maintenance Plan SIP. Annual motor vehicle emissions budgets are being proposed for the attainment year, 2008, and for the final year ofthe Maintenance Plan, 2025, for primary PM2.s and the precursor pollutant NOx. The Maintenance Plan also includes motor vehicle emissions estimates for the interim years 2015 and 2020 in orderto demonstrate that total emissions from all sectors remain belowthe 2008 attainment yeartotal; however, these interim year motor vehicle emissions estimates are not being proposed as formal motor vehicle emissions budgets. The Maintenance Plan also includes estimates ofemissions ofS02, however, as motor vehicles have not been identified as a significant source ofS02, motor vehicle emissions budgets are not being proposed for this pollutant. The proposed 2008 and 2025 annual NOx and direct PM2.5 motor vehicle emissions budgets were developed consistent with the motor vehicle activity assumptions and emissions control strategies incorporated into the 8-hour ozone Attainment Demonstration and Maintenance Plan SIPs. The budgets reflect an emissions level determined using actual motor vehicle VMT for 2008 and VMT growth at an annual rate of 1.5% from year 2008 levels to 2025. A motorvehicle emissions budget is that portion ofthe total allowable emissions allocated to highway and transit vehicle use that are defined in the SIP for a certain year. The rules governing transportation conformity require certain transportation activities to be consistentwith motor vehicle emissions budgets contained in control strategy implementation plans ( 40 CFR § 93.118). Section 93.101 ofthe rule defines a "control strategy [State] implementationplanrevision" as a "planwhich contains specific strategies for controlling the emissions and reducing ambient levels ofpollutants in order to satisfy CAA requirements ofreasonable further progress and attainment." In orderto demonstrate conformityto the motor vehicle emissions budget, emissions from the implementation ofatransportation plan or atransportation improvement program must be less than orequal to the budget level (40 CFR §93.118(a)). The motor vehicle emissions budgets established and described herein were developed consistent with the methodology and control strategy assumptions in place in the region. The effects ofmotor vehicle control measures are incorporated into the emissions produced bythe U.S. EPA'sMOVES model. These control measures include the implementation ofnational motor vehicle emissions standards, the operation ofa vehicle inspection and maintenance (1/M) program, and the required use ofreformulated gasoline and low sulfur gasoline and diesel fuel. The U.S. EPA'stransportation conformityregulations allow for the use ofa "safety margin" in the development ofmotor vehicle emissions budgets for Maintenance Plans. A safety margin is defined as "the amount bywhich the total projected emissions from all sources ofa given pollutant are less than the total emissions that would satisfy the

21applicable requirement for reasonable further progress, attainment, ormaintenance." Accordingto table 4.6, 

### PM25 and NOx emissions for the end ofthe maintenance plan year 2025 are 2,484 and 118,437 tons peryear, respectively, less than the year 2008 attainmentyear levels. As year 2025 emissions levels are projected to be substantially less than the attainment year 2008 emissions, a 15% safety margin is being proposed to be added to the 2025 estimated motor vehicle emissions to make up the motor vehicle emissions budget. The 15% increase would equate to an increase of310 tpy ofPM2.5and 5,768 tpd ofNOx. The motorvehicle emissions budgets, which reflect the VMT and control program assumptions and methodology described here, are listed in Table 5.1.

Year 

### 2008 2025 Table 5.1 Proposed Chicago PM2 . 5Maintenance Plan 

### 2008 and 

### 2025 MotorVehicle Emissions Budgets (tons peryear) Estimated Emissions Safety Margin MotorVehicleEmissions Budgets PM2.s NOx PM2.s NOx PM2.s NOx 5,100 127,951 

### - - 

## - - 5,100 127,951 2,067 38,456 310 5,768 2,377 44,224 Complete details onthe derivation ofthe motorvehicle emissions budgets, including discussion ofthe MOVES model inputs and assumptions are included in Appendix B of this report.

22

### 6.0 CONTINGENCY MEASURES 6.1 Contingency Measures Section 175(A) ofthe CAA specifies the requirements for Maintenance Plans, including provisions for contingency measures that will be implemented ifviolations ofthe annual PM2 . 5 NAAQS are measured after redesignation to attainment. A list ofpotential contingency measures that would be implemented in such an event should also be included in the Maintenance Plan. Finally, the plan should provide a commitmentto submit a revised Maintenance Plan eight years after redesignation to ensure continued maintenance for the next ten-year maintenance period. Contingency measures are intended to provide further emissions reductions in the event that violations ofthe annual PM2 . 5 NAAQS occur after redesignation to attainment. While these measures do notneed to be fully adopted bythe Illinois Pollution Control Board (IPCB) priorto the occurrence ofNAAQS violations, the contingencyplan should ensure that the contingency measures are adopted expeditiously once they are triggered. The Maintenance Plan must identify the triggers that determine when contingency measures will be adopted, and the measures that the state will consider. Illinois EPA's contingency plan for the Chicago NAA is described in Table 6.1. Consistent with this plan, Illinois agrees to adopt and implement, as expeditiously as practicable, the necessary corrective actions in the eventthat violations ofthe annual PM2.s NAAQS occurwithin the Chicago maintenance area afterredesignation to attainment. As described in Section 5.0 ofthis report, Illinois has adopted and is continuingto implement a range ofcontrol measures that will greatlyreduce precursor emissions, both locally and statewide. Illinois commits to continue to implementthe identified control measures, although the Illinois EPA anticipates thatthese emissions reductions will be sufficientto mitigate exceedances orviolations ofthe NAAQS that may occur in the coming years without further regulatory action. The contingency plan provides for different levels ofcorrective responses should ambient annual PM25 levels exceed the NAAQS in any year; ifemissions in the NAA increase significantly above current attainment levels; or ifthe NAAQS is violated. A Level I response would occur in the event that: 1) the average ofthe annual PM2 .5concentration for the three mostrecent years at any monitoring site in the Illinois portion ofthe Chicago NAA exceeds 15 micrograms percubic meter, or 2) iftotal PM25, S02orNOx emissions increase more than 5% above the levels contained in the attainment year (2008) emissions inventory. Ifexceedances ofthe annual PM2.s NAAQS are observed in Lake and Porter counties in Indiana, Illinois commits to work with the IndianaDepartment of Environmental Management (IDEM) to develop appropriate corrective measures. It should be noted that U.S. EPA does not require a state to implement contingency measures when occasional exceedances are recorded. The Illinois EPA's voluntary commitment to initiate a Level I response is intendedto prevent future violations ofthe NAAQS from ever occurring.

23Table 6.1 Contingency Plan for the Chicago PM2.5 NonattainmentArea Contingency Measure Action to be Taken List ofPotential ContingencyMeasures Trigger Level I Trigger Point Source Measures IL will evaluate air quality, or 

### • IL Multi-Pollutant Program for 

### • Highest monitored determine ifadverse emissions trends electric generating units PM2s are likely to continue. Ifso, IL will 

### • NOxRACT concentration determine what and where controls 

### • Clean Air Transport Rule, after exceeding 15.0 may be required, as well as level of promulgation by U.S.EPA ug/m**3 in any emissions reductions needed, to avoid a 

### • Best Available Retrofit year at any violation ofthe NAAQS. The study Technology (BART) monitoring station shall be completed within 9 months. If 

### • Broader geographic applicability in the Chicago necessary, control measures shall be ofexisting measures maintenance area. adopted within 18 months of determination and implemented as expeditiously as practicable, taking into Mobile Source Measures 

### • The Chicago considerationthe ease of 

### • Tier 2 Vehicle Standards and Low maintenance area's implementation and the technical and Sulfur Fuel total PM2

_ 5, NOx economic feasibility ofthe selected 

### • Heavy Duty Diesel Standards and or so2 emissions measures. Low SulfurDiesel Fuel increase more than 

### • High-enhanced 1/M (OBDII) 5% above the 

### • Federal railroad/locomotive levels included in standards the 2008 emissions inventories. 

## • Federal commercial marine vessel engine standards Level II Trigger IL will conduct a thorough analysis to Area Source Measures 

### • A violation ofthe determine appropriate measures to Architectural/Industrial 

## • NAAQS at any address the cause ofthe violation. Maintenance (AIM) Coatings monitoring station Analysis shall be completed within 6 in the Chicago months. Selected measures shall be 

## • Commercial and Consumer maintenance area. implemented within 18 months ofa Products violation. 

## • Aerosol coatings 

### • Portable fuel containers

Illinois commits to compiling PM2.s, S02, and NOx emissions inventories for the Chicago area every three years for the duration ofthe Maintenance Plan to facilitate the emissions trends analysis included in the contingency plan under Level I. The Illinois EPA will evaluate the causes ofhigh PM25 levels orthe emissions trends and to determine appropriate control measures needed to assure continued attainment ofthe annual PM2.s NAAQS. Under Level I, measures that could be implemented in a short time would be selected so as to be in place quickly after the Illinois EPA is aware that corrective measures have been triggered. Control measures selected underLevel I will be adopted in most cases within 18 months after a determination is made, and implemented, generally, within 24 months ofadoption bythe IPCB. A Level II response would be implemented in the event that a violation ofthe annual PM2.s NAAQS were to be measured at a monitoring site within the Chicago maintenance

24area (including sites in Indiana and Illinois). In orderto select appropriate corrective measures, the Illinois EPA will work with IDEM to conduct a comprehensive study to determine the causes ofthe violation and the control measures necessaryto mitigate the problem. The analysis will examine the following factors:

• the location and severity ofthe ambient PM2

_ 5 exceedances; • the weatherpatterns contributing to the elevated PM2.s levels; • potential contributing emissions sources; • the geographic applicability ofpossible contingency measures; • emissions trends, including timeliness ofimplementation ofscheduled control measures; • current and recently identified control technologies; and • air quality contributions from outside the maintenance area. Contingency measures will be selected from those listed in Table 6.1 orfrom any other measure deemed appropriate and effective at the time the selection is made. Itis expected that implementation ofonly a few ofthese measures would be necessary. The selection between measures will be based upon cost-effectiveness, emissions reduction potential, ease and timing ofimplementation, and other appropriate factors. Implementation ofnecessary controls in response to a Level II triggerwill take place as expeditiously as possible, but in no event laterthan 18 months afterthe Illinois EPA makes a determination, based on quality-assured ambient data, that a violation ofthe NAAQS has occurred. Adoption ofadditional control measures is subjectto necessary administrative and legal processes. The Illinois EPA will solicit input from all interested and affected persons in the area priorto selecting appropriate control measures. No contingencymeasure will be implemented without providingthe opportunity for full public participation. This process will include publication ofnotices, an opportunity for public hearing, and other measures required byIllinois law. 6.2 Commitmentto Revise Plan As noted in Section 4.5 above, the Illinois EPA commits to review its Maintenance Plan eight years after redesignation, as required by Section 175(A) ofthe CAA. The Maintenance Plan revision is intended to ensure continued attainment ofthe annual 

### PM 25 NAAQS for an additional ten-year period. 6.3 Public Participation In accordance with Section 110(a)(2) ofthe CAA, Illinois is required to have a public comment period arid provide the opportunity for a public hearing on the Maintenance Plan priorto adoption. Public participation in the SIP process is provided for as follows:

25• Notice ofavailability ofthe Chicago 

### PM25 Maintenance Plan document and the time and date ofthe public hearing was published in the Chicago Sun-Times on July 8, 2011.

• Ifrequested, the public hearing to receive comments on the Chicago Maintenance Plan was scheduled for August 18, 2011, at 1:00 p.m. in the Sangamo Room at the Illinois EPA's Headquarters at 1021 N. Grand Ave. East, Springfield, Illinois.

• A 30-daypublic comment period was open afterthe public hearing to receive comments on the Maintenance Plan. A summary ofthe comments received and Illinois EPA's responses thereto is included as part ofthe submittal to U.S. EPA. 6.4 Legal Authority to Implement and Enforce The Maintenance Plan must contain a demonstration that the State ofIllinois has the necessary legal authority to implement and enforce the measures relied upon to attain and maintain the NAAQS. Illinois has the legal authority to implement and enforce the requirements ofthis SIP submittal pursuantto the Illinois Environmental Protection Act.



### 26

### 7.0 CONCLUSIONS The Chicago nonattainment area has attained the 1997 annual PM2

_ 5 NAAQS and has complied with the applicable provisions ofthe CAA required ofPM2

_ 5 NAAs. Illinois has performed an analysis that demonstrates that the Chicago NAA has attained the 1997 annual PM2

_ 5 NAAQS and believes the air quality improvements are due to permanent and enforceable control measures. Supporting documentation is contained herein. The Illinois EPA has prepared a Maintenance Plan that meets the requirement ofthe Clean AirAct. This Maintenance Plan provides for the continued attainment ofthe 1997 annual PM2

_ 5 NAAQS for aperiod ofat least ten years after U.S. EPA has formally redesignated the area to attainment. This Maintenance Plan provides adequate contingency measures for potential, additional emissions reductions in the event that future violations ofthe 1997 annual PM2.s NAAQS are observed in the area. The Illinois EPA has prepared a comprehensive emissions inventory ofPM2

_ 5and its precursors for the "attainment" year, 2008, and has prepared projections ofthe emissions inventoryto 2015, 2020 and 2025. These emissions projections indicate that emissions levels in the Chicago nonattainment areawill continue to remain much lowerthan emissions from the attainment year 2008 levels, thereby maintaining the PM2

_ 5 NAAQS in future years. The Illinois EPA commits to continue to operate an appropriate air quality monitoring networkto verify the maintenance ofthe attainment status once the area hasbeen redesignated. The Illinois EPA has the legal authority to implement and enforce all control measures. Finally, the Chicago PM25 Maintenance Plan includes year 2008 and 2025 on-road motor vehicle emissions budgets for PM2.5 and NOx for use in transportation conformity determinations to assure that any increases in emissions from this sector do not jeopardize continued attainment ofthe annual PM2.5 standard during the ten-year maintenance period. The Chicago Maintenance Plan has been prepared in accordance withthe requirements specified in U.S. EPA's guidance document, and additional guidance received from U.S. EPA staff.



### 27

## APPENDIXA SummaryofAmbientAirMonitoringData (2007-2009)

28

### Table A.l 2007-2009 AnnualPM2.5 

### Design Values for Monitors in the Chicago Nonattainment Area
County Monitoring Site 

### 2007 2008 2009 Design Value Cook Blue Island 14.3 12.5 11.7 12.8 Cook Chicago-Com Ed 14.3 11.9 11.1 12.4 Cook Chicago-Springfield 15.2 12.0 11.3 12.8 Cook Chicago-Mayfair 15.5 12.2 12.7 13.5 Cook Chicago-SE Police 14.1 11.8 11.0 12.3 Cook Chicago-Washington 15.7 12.5 11.6 13.3 Cook Cicero 14.8 13.3 12.0 13.4 Cook Des Plaines 12.7 11.4 11.0 11.7 Cook McCook* 15.6 12.9 12.6 13.7 Cook Northbrook 13.2 10.1 9.3 10.9 Cook Schiller Park* 15.4 13.6 12.9 14.0 Cook Summit 14.8 12.0 11.6 12.8 DuPage Naperville 13.8 11.3 9.8 11.6

Kane Aurora 14.5 10.3 10.0 11.6 Kane Elgin 13.2 10.8 9.6 11.2 Lake Zion 11.9 9.3 8.8 10.0 McHenry Cary 11.6 10.1 9.6 10.4 Will Braidwood 12.1 10.3 8.7 10.4 Will Joliet 14.6 11.7 10.5 12.3 Lake IN Franklin School 14.4 12.0 11.3 12.6 Lake IN Griffith 13.2 11.7 11.0 12.0 Lake IN Madison St. 14.6 12.3 12.1 13.0 Lake IN Hammond-Purdue 13.8 11.7 15.9 13.8 Lake IN Clark HS 13.7 12.4 10.8 12.3 Porter IN Ogden Dunes 13.8 10.9 11.3 12.0
*- Annual Standard does not apply atthese monitoring sites Annual averages listed in underlined italics based on incomplete data.



### 29

## APPENDIXB Transportation Conformity

30TRANSPORTATION CONFORMITY
This section describes the development ofthe Chicago NAA motor vehicle emissions budgets associated with the PM2.5 Maintenance Plan SIP. Annual motor vehicle emissions budgets are being proposed for the attainment year, 2008, and 2025, the final year ofthe initial maintenance period for direct motor vehicle PM2.5 emissions and for the precursor pollutantNOx. These budgets were developed consistent with the motor vehicle activity assumptions and emissions control strategies incorporated into the 

### PM 25 maintenance plan analysis. Background Section 176(c)(4) ofthe Clean Air Act (CAA) Amendments of 1990 requires that transportation plans, programs, and projects which are funded or approved under Title 23 USC must be determined to conform with State or Federal air implementation plans. A motorvehicle emissions budget is that portion ofthe total allowable emissions allocated to highway and transit vehicle use that are defined in the SIP for a certain year. Section 93.101 ofthe rule defines a "control strategy [State] implementationplan revision" as a "planwhich contains specific strategies for controllingthe emissions and reducing ambient levels ofpollutants in order to satisfY CAA requirements ofreasonable further progress and attainment." In orderto demonstrate conformity to the motor vehicle emissions budget, emissions from the implementation ofa transportation plan or a transportation improvement program (TIP) must be less than orequal to the budget level (40 CFR § 93.118(a)). Transportation conformity will be based on these submitted on road motor vehicle emissions budgets after the U.S. Environmental Protection Agency ("U.S.EPA") determines that the budgets meetthe adequacy criteria ofthe transportation conformity rule under §93.118(e). The motor vehicle emissions budgets in this submittal are adequate as each ofthe six criteria under §93.118(e) is satisfied. These six criteria include: 1. The submitted control strategy implementation plan revision ormaintenance plan was endorsed bythe Governor (orhis or her designee) and was subject to a State public hearing. 2. Before the control strategy implementation plan ormaintenance plan was submitted to EPA, consultation among federal, State, and local agencies occurred: full implementation plan documentation was provided to [US]EPA; and [US]EPA's stated concerns, ifany, were addressed; 3. The motorvehicle emissions budgets(s) is clearly identified and precisely quantified; 4. The motorvehicle emissions budget(s), when considered togetherwith all other emission sources, is consistentwith all applicable requirements for reasonable further

31progress, attainment, or maintenance (whichever is relevant to the given implementation plan submission); 5. The motor vehicle emissions budget(s) is consistent with and clearlyrelated to the emissions inventory and the control-measures in the submitted control strategy implementation plan revision ormaintenance plan, and 

### 6. Revisions to previously submitted control strategy implementation plans explain and document any changes to previously submitted budgets and control measures, impacts on point and area source emissions; any changes to established safety margins; and reasons for the changes (including the basis for any changes related to emission factors orestimates ofvehicle miles traveled). The PM2.5 attainment demonstration SIP and the associated motor vehicle emissions budgets have been developed by the Illinois Environmental ProtectionAgency (Illinois EPA), the designated air quality agency for the State ofIllinois. The required public hearing to accept public comment on the proposed motor vehicle emissions inventory was held at 1:00PM, on July 14, 2010 in Room 9-040 ofthe James R. Thompson Center in downtown Chicago. Notification ofthis hearing was printed in the Chicago Sun Times on June 11, 2010. Comments on the proposed attainment demonstration and motor vehicle emissions budgets were accepted for 30 days after the public hearing. A "Responsiveness Summary" which addresses the comments received was included in the final submission. Regarding this revision to the Chicago PM25Maintenance Plan, notice ofa comment 30- day comment period was posted on the Illinois EPA'swebsite and printed in the Chicago Sun Times on July 8, 2011. A public hearing to discuss the revised Maintenance Plan and associated motor vehicle emissions budgets was to be held on August 18, 2011, ifit was requested. Comments were required to be postmarked byAugust 8, 2011, unless a public hearing was requested. No request for a public hearing was received. All comments were addressed in the attached Responsiveness Summary. None ofthe comments affected the proposed motorvehicle emissions budgets. In compliance with adequacy criterion #2, an interagency consultation meeting was held with members ofthe Chicago Metropolitan Agency for Planning (CMAP) Tier 2 Consultation Team on June 25, 2010 in Chicago. At this meeting, the Illinois EPA representative discussed the requirements for the maintenance plan as they relate to transportation conformity and explained the derivation ofthe proposed motor vehicle emissions budgets. A follow-up meeting ofthe Tier 2 Conformity Consultation Team to discuss the revised MOVES-based motor vehicle emissions budgets was held at the CMAP offices on June 28, 2011. Compliance with the remaining adequacy criteria is contained within the narrative ofthe attainment demonstration document and this transportation conformity section. The motor vehicle emissions budgets proposed and described herein were developed consistent with the methodology and control strategy assumptions used in the
32development ofthe emissions estimates contained in the Chicago PM2.5 Maintenance Plan. The effects ofthese controls are incorporated into the emissions inventory estimates generated bythe U.S.EPA's MOVES2010 (MOVES) model. Following is a discussion ofthe inputs and assumptions used in the development ofthe motor vehicle emissions budgets. Vehicle Miles Travelled: The attainment year 2008 motor vehicle emissions estimates contained Chicago PM2.5 Maintenance Plan incorporate county-and township-level 2008 annual vehicle miles traveled (VMT) levels from the Illinois Department of Transportation (IDOT). The 2008 annual VMTtotal for the 6-county-3-township Chicago NAA was approximately 58.8 billion miles. For future year emission estimates, VMT was grown to the target year at a compound growth rate of 1.5% peryear. Applying this growth factor to the 2008 VMT level yields future year annual VMT projections of65.2 billion for 2015, 70.3 billion for 2020, and 75.7 billion for 2025. Meteorological Data: U.S. EPA guidance for the use ofthe MOVES model requires the use ofrepresentative local temperature and absolute humidity data. Average 2008 maximum and minimum monthlytemperatures for the region were obtained from the National Weather Service local climatological data (LCD) for O'Hare International Airport. Absolute humidities correspondingto the average temperatures were calculated from LCD information as well. These 2008 temperatures and absolute humidityvalues, shown below, were used in the year 2025 emissions modeling. 2008 Minimum and Maximum Temperatures for Chicago, from O'Hare NWS Data Month Jan Feb Mar Apr May June July Aug Sep Oct Nov Dec Min, (°F) 15 16 27 39 45 61 64 64 57 47 32 14 Max, (°F) 32 30 43 60 66 81 84 82 75 62 46 32 2008 Absolute Humidity Corresponding to theTemperatures Above Month Jan Feb Mar Apr May June July Aug Sep Oct Nov Dec AH, grains/lb 17 14 21 34 41 73 83 74 71 39 25 15
MotorVehicleEmissions Controls: Beyondthe U.S. EPA's federal motorvehicle control program emissions standards, the primary local motorvehicle emissions control programs that were in place in the Chicago NAA in 2008, and are projected to still be required in 2025 are a vehicle inspection and maintenance (I/M) program and the required use of reformulated gasoline (RFG). Inspection and Maintenance (liM): The Illinois liM program in effect since 2007 requires biennial On-Board Diagnostics II (OBD) testing on all model year (MY) 1996 and newer (MY96+) light-duty gasoline vehicles (cars and light-dutytrucks), and biennial exhaust idle and gas cap testing on MY96+heavy duty gasoline vehicles including gasoline-powered buses, registered in the liM testable area. Motorcycles and diesel vehicles are not subject to 

### liM. The program includes a 4-year grace period for new vehicles. This post-2007 liM program was established when the Illinois legislature
33amended the Illinois Vehicle Inspection law in 2005 to (a) end dynamometertesting of vehicles, (b) require an OBD-based program beginning in February 2007, and (c) remove the requirement for testing compliant pre-MY96 vehicles. The Chicago I/M program vehicle testing domain includes the urbanized areas in the Chicago NAA. An 

### "liM Coverage" percentage was developed based on the amount of VMT from vehicles subject to the inspection program compared to total area VMT. The 

### liM Coverage percentage for the Chicago 8-hour ozone NAA is 91.5%. Fuels: The use offederal RFG has been required in the Chicago NAA since 1995. The 8-hour ozone Attainment Demonstration and original Maintenance Plan assumed the use ofnorthern grade RFG in 2008 and beyond. RFG was and is assumed to contain 10% ethanol. The MOVES model can account for other fuels, such as E85, natural gas, methanol, etc, but for all practical purposes the gallons ofsuch alternative fuels and hence the number ofvehicles using them is very small compared to the number ofgasoline and diesel vehicles, therefore, the use ofsuch fuels was not considered. Gasoline Sulfur: The federal Tier 2 regulations require gasoline sulfur levels to average no greaterthan 30 parts permillion (ppm) with a maximum of80 ppm beginning in 2007. There are no Illinois gasoline sulfurrequirements, therefore, the MOVES default gasoline sulfur levels were used in the emissions modeling. Diesel Sulfur: The federal Tier2 regulations limitthe level ofsulfur in diesel 'fuel requiring on- highway diesel fuel to 15 ppm beginning in 2006. There are no Illinois diesel sulfurrequirements, therefore, the MOVES default diesel sulfur levels were used in the emissions modeling. FuelVolatility: The volatility ofsummerRFG, measured as Reid vaporpressure (RVP), is not specifically regulated. However, a fuels' RVP is one ofthe primary characteristics controlled byrefiners in orderto meetthe RFG performance standards. The MOVES model contains default RVP levels for different seasons ofthe year based on fuel compliance testing. Therefore, the MOVES default RVP levels were used in the emissions modeling. Vehicle Registration Distribution: A Chicago area-specific vehicle registration distribution (RD) profile based upon 2008 information data was developed by Illinois EPA's Division ofMobile Source Programs from vehicle age data for 2008 provided by the Illinois Secretary ofState's Department ofMotorVehicles. The RD is the fraction of vehicles ofa given vehicle type and age in the fleet ofvehicles ofthattype as a whole. Differentvehicle types have different RDs Chicago-areaRDs generally show fewer oldervehicles than the nationwide average or default, because vehicles in the Chicago areatend to wear out faster than they do in the rest ofthe country due to rust from road salt and heavy city driving.

34Source TypePopulation represents the number ofvehicles ofeach MOVES vehicle type in the fleet as a whole within the area under consideration. Accurate local source-type populations were not available; therefore the MOVES default fractions modified by VMTs byvehicle type were used. VMT Temporal Fractions are the VMT fractions ofannual VMTbymonth ofthe year, ofweekly VMT by day ofthe week, and daily VMT by hour ofthe day. The Illinois EPA uses temporal fractions derived from data collected from continuous count stations and presented by IDOT. Temporal fractions vary by road type. Speed distributions are the fractions ofVMT on a given road type by given vehicle types in various speed ranges (bins). Thus, on a typical Urban Arterial, a small fraction ofthe vehicles are traveling at less than 10 mph (plus orminus 5 mph), more at 20 mph, more at 30mph, most at 40 mph, less at 50 mph, and so on. These fractions differ by hour ofthe day-in more congested conditions during rush hours, the maximum fraction might be in the 30 mph range ratherthan the 40 mph range. MOVES uses speed distributions when aggregating emissions (or emission rates) for vehicles at different speeds. The Illinois EPA used the speed distributions derived from the CMAP transportation demand model. Ramp fraction is the fraction oftotal VMT on limited-access highways such as Interstates that is from on- and off-ramps to or from those highways. Driving on limitedaccess highways is more or less at uniform speed, but driving on ramps involves considerable acceleration and deceleration; and these speed changes affect emissions. The default MOVES Ramp Fractions are 15% on Rural Interstates, 10% on Urban Interstates, and 2% on OtherFreeways and Expressways. Illinois does not have actual or observed Ramp Fraction data; therefore the MOVES default values were used. Road TypeDistribution is the (fraction of) VMT on different road categories within an area under consideration. The Illinois EPA uses VMT data byHPMS functional class (FC) published by IDOT as the basis ofits emission calculations. The Road Type Distribution for Rural Interstates in a county is the county's Rural Interstate VMT divided by the county's total all-road-type VMT. Similar calculations can be made for MOVES road types and vehicle types. Safety Margin: The U.S. EPA's transportation conformityregulations allow for the use ofa safety margin in the development ofmotorvehicle emissions budgets for Maintenance Plans. A Safety Margin is defined as "the amount bywhich the total projected emissions from all sources ofa given pollutant are less than the total emissions that would satisfy the applicable requirement for reasonable further progress, attainment, or maintenance." According to table 4.6, PM25 and NOx emissions for the end ofthe maintenance plan year 2025 are 2,484 and 118,437 tons peryear, respectively, less than the year 2008 attainment year levels. As year 2025 emissions levels are projected to be substantially less than the attainment year 2008 emissions, a 15% safety margin is being proposed to be added to the 2025 estimated motor vehicle emissions to make up the motor vehicle emissions budget. The 15% increase would equate to an increase of310 tpy ofPM25and 5,768 tpd ofNOx.
35The motorvehicle emissions budgets, which reflect the VMT, motor vehicle fleet characteristics, emissions and control program assumptions, and safety margin described herein, are identified below.



### Year 2008 2025 

### Proposed Chicago PM2 .5

### MaintenancePlan 2008 

### and 2025 

### MotorVehicleEmissions Budgets (tons per year) 

### EstimatedEmissions SafetyMargin MotorVehicle Emissions Budgets PM2.s NOx PM2.s NOx PM2.s NOx 5,100 127,951 

## -- - - 5,100 127,951 2,067 38,456 310 5,768 2,377 44,224

36