Technical Support Document:

Recommended Attainment/Nonattainment Designations 

in Illinois for the 2010 Revised Primary 1-Hour SO2

National Ambient Air Quality Standard

AQPSTR 11-02

June 2, 2011

Illinois Environmental Protection Agency

Division of Air Pollution Control

1021 North Grand Avenue East

P.O. Box 19276

Springfield, IL 62794-9276

www.epa.state.il.us
2

Table of Contents

TABLES......................................................................................................................................... 3

FIGURES....................................................................................................................................... 4

INTRODUCTION......................................................................................................................... 5

FEDERAL GUIDANCE............................................................................................................... 6

FIVE FACTOR ANALYSIS ............................................................................................................................ 7

1. AIR QUALITY DATA.................................................................................................................................. 7

2. EMISSIONS-RELATED DATA.................................................................................................................... 7

3. METEOROLOGY .......................................................................................................................................... 7

4. GEOGRAPHY/TOPOGRAPHY .................................................................................................................... 7

5. JURISDICTIONAL BOUNDARIES............................................................................................................... 8

ILLINOIS AIR QUALITY .......................................................................................................... 8

ILLINOIS 5 FACTOR ANALYSIS .......................................................................................... 11

TAZEWELL COUNTY................................................................................................................... 11

LA SALLE COUNTY .................................................................................................................... 17

COOK AND WILL COUNTIES....................................................................................................... 22

MADISON COUNTY .................................................................................................................... 27

RECOMMENDATIONS............................................................................................................ 33
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TABLES

Table 1 2008-2010 Illinois SO2 Design Values (ppb)................................................ 9

Table 2 Peoria Area Air Quality Data for 2008-2010 (ppb)....................................... 11

Table 3 Tazewell and Peoria County Reported SO2 Emissions for 2007-2009 ................ 12

Table 4 La Salle County Air Quality Data for 2008-2010 (ppb)........................................... 17

Table 5 La Salle County Reported SO2 Emissions for 2007-2009 ............................... 17

Table 6 Cook and Will County Air Quality Data for 2008-2010 (ppb) ......................... 22

Table 7 Cook and Will County Reported SO2 Emissions for 2007-2009 ....................... 23

Table 8 Metro-East Area Air Quality Data for 2008-2010 (ppb)................................ 28

Table 9 Madison County Reported SO2 Emissions for 2007-2009 .............................. 28

Table 10 Recommended Attainment/Nonattainment Designations in Illinois for the 2010 

Revised Primary 1-Hour SO2 National Ambient Air Quality Standard................. 35

Table 11 SO2 NAA Five Factor Documentation .................................................... 36
4

FIGURES

Figure 1 Illinois 1-hour SO2 Design Values 2008-2010 ...................................... 10

Figure 2 Location of Major SO2 Emission Sources in Tazewell and Peoria Counties..... 12

Figure 3 Greater Peoria Airport Climatological Wind Rose .................................. 13

Figure 4 Pekin Pollution Rose...................................................................... 14

Figure 5 Aerial Photo of the Pekin Monitor and nearby Facilities ............................ 15

Figure 6 Proposed SO2 Nonattainment Area Boundary for Tazewell County .............. 16

Figure 7 Location of Major SO2 Emission Sources in La Salle County..................... 18

Figure 8 Greater Rockford Airport Climatological Wind Rose............................... 19

Figure 9 Oglesby Pollution Rose................................................................. 20

Figure 10 Aerial Photo of the Oglesby Monitor and nearby Facility .......................... 20

.

Figure 11 Proposed SO2 Nonattainment Area Boundary for La Salle County ............... 21

 

Figure 12 Location of Major SO2 Emission Sources in Cook and Will Counties............. 23

Figure 13 Chicago-O’Hare Airport Climatological Wind Rose ................................ 24

Figure 14 Lemont Pollution Rose .................................................................. 25

 

Figure 15 Aerial Photo of the Lemont Monitor and nearby Facilities ........................... 26

.

Figure 16 Proposed SO2 Nonattainment Area Boundary for Cook and Will Counties ..... 27

Figure 17 Location of Major SO2 Emission Sources in Madison County ..................... 29

 

Figure 18 St. Louis-Lambert Field Climatological Wind Rose ................................ 30

Figure 19 South Roxana Pollution Rose ........................................................... 31

Figure 20 Aerial Photo of the South Roxana Monitor and nearby Facility .................... 31

 

Figure 21 Proposed SO2 Nonattainment Area Boundary for Madison County .............. 32

Figure 22 Proposed SO2 Nonattinment Areas..................................................... 34
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Introduction

On June 2, 2010, the U.S. Environmental Protection Agency (U.S. EPA) revised the primary 

Sulfur Dioxide (SO2) National Ambient Air Quality Standard (NAAQS) in response to current 

scientific evidence which links short-term exposure to SO2 with adverse health effects in 

humans. U.S. EPA health studies show that short-term exposure to SO2, ranging from 5-

minutes to 24-hours, results in adverse respiratory effects and increased asthma symptoms, 

particularly in children, the elderly, and asthmatics. According to U.S EPA, there is currently 

little evidence suggesting a relationship between long-term exposure to SO2 and health effects. 

As a result, U.S. EPA revoked both the previous 24-hour and annual primary SO2 standards and 

established a new primary 1-hour SO2 standard at a level of 75 parts per billion (ppb) (75 FR

35520; June 22, 2010). As part of the 2010 revised primary SO2 NAAQS (further referenced as 

the revised SO2 standard), U.S. EPA also modified how attainment is determined. The revised 

SO2 standard is attained when the three-year average of the annual 99th percentile 1-hour daily 

maximum concentrations does not exceed 75 ppb (75 FR 35520; June 22, 2010). U.S. EPA will 

address the secondary SO2 standard as part of a separate review.

Section 107(d) of the Clean Air Act (CAA) governs the process for area designations, and directs 

states to submit their SO2 designation recommendations to U.S. EPA by June 3, 2011. 

Following the promulgation of a new or revised air quality standard, the Clean Air Act (CAA) 

requires the Governor to recommend initial designations of the attainment status for all areas of 

the State. Areas can be classified as nonattainment (does not meet, or contributes to a nearby 

area that does not meet the NAAQS), attainment (meets the NAAQS), or unclassifiable (cannot 

be classified based on available data). Illinois is, therefore, required to provide recommendations 

for attainment/nonattainment area boundaries for the 2010 revised primary SO2 standard. The 

U.S. EPA will act on the State’s recommendations by both affirming and promulgating the 

recommended designation boundaries, or by promulgating new designations. U.S. EPA stated in 

its preamble to the 2010 NAAQS, that in addition to air monitoring data, refined dispersion 

modeling information may be used as part of an analytical approach to designations. However,

according to the U.S. EPA March 24, 2011 memorandum entitled, Area Designations for the 
6

2010 Revised Primary Sulfur Dioxide National Ambient Air Quality Standards, the U.S EPA 

does not believe it would be “realistic or appropriate to expect states to complete modeling for all 

significant sources of SO2 and assess the results in time for the June 2011 designation 

recommendations”. States would instead present modeling to address additional violations in 

the course of developing State Implementation Plan (SIP) revisions under Section 110(a) of the 

Clean Air Act as a, “basis for re-designation of nonattainment and unclassifiable areas to 

attainment” (75 FR at 35570). Illinois does not intend to submit dispersion modeling in support 

of designations at this time. Rather, IEPA will complete dispersion modeling in the course of 

developing SIP revisions.

Federal Guidance

The Illinois Environmental Protection Agency (IEPA) relied on guidance identified in a 

memorandum issued by U.S. EPA on March 24, 2011 which referenced pages in the preamble of 

the lead NAAQS final rule regarding criteria for developing this recommendation and for 

establishing the geographic boundaries of nonattainment areas (NAA) for the 2010 revised SO2

standard. In this guidance, U.S. EPA recommended that states designate areas with air quality 

data showing violations of the SO2 NAAQS, and nearby areas that cause or contribute to 

NAAQS violations, be designated nonattainment. Due to the localized nature of SO2 impacts,

U.S. EPA also recommends that the “county line” associated with the violating monitor(s) serve 

as the starting point, or presumptive boundary, for new SO2 nonattainment areas. U.S. EPA 

provides states with the ability to depart from county boundaries based on area-specific analyses. 

States may request nonattainment area boundaries that are smaller than the existing violating 

county boundaries where counties, or portions of counties, do not contribute to nonattainment 

based on an examination of five factors. States may also request nonattainment area boundaries 

that are larger than the current county to include adjacent counties when those counties contain 

emission sources and other factors that may contribute to the nonattainment problem. This 

report provides the basis for recommendations by the IEPA for attainment/nonattainment 

designation boundaries for all areas in the State of Illinois for the revised SO2 standard.
7

Five Factor Analysis

The U.S. EPA recommends that states consider the following five factors in assessing whether to 

depart from county boundaries as the designated nonattainment area boundary:

1. Air Quality Data: an evaluation of the design value calculations for each monitor in the 

State. This calculation consists of the 3-year average of the annual 99th percentile daily 

maximum 1-hour SO2 concentrations collected at each monitor. A detailed discussion of 

air quality in Illinois is provided in the sections below.

2. Emissions-Related Data: an evaluation of SO2 emissions from sources located in and 

around the violating area which may potentially contribute to observed or modeled 

violations of the NAAQS. The emissions data used in this analysis are based on actual 

SO2 emissions reported to the IEPA for 2007 through 2009. 

3. Meteorology: an evaluation of weather conditions, including wind speed and direction 

that affect the plume of sources contributing to ambient and monitored SO2

concentrations. Pollution roses are derived from IEPA sites in the proposed NAA areas, 

and all sites use either collocated wind measurements, or the nearest IEPA monitoring 

site with wind direction measurements, along with hourly SO2 concentrations. The 

pollution roses show the frequency of wind directions at the monitor when 1-hour 

concentrations of SO2 that exceed the standard are occurring. Detailed meteorology used 

in IEPA’s analysis is discussed in the following sections.

4. Geography/Topography: Includes an evaluation of the physical features of the land that 

might have an effect on the airshed and, therefore, on the distribution of SO2 at and near 

the monitors. Due to the fact that none of the recommended SO2 nonattainment areas in 

Illinois have any geographical or topographical barriers that significantly limit air 
8

pollution transport within the airsheds, the geography/topography factor did not play a 

significant role in determining the nonattainment boundaries in Illinois.

5. Jurisdictional Boundaries: Includes an analysis of areas that provide clearly defined 

legal boundaries including landmarks or geographic coordinates to carry out air quality 

planning and enforcement functions for the nonattainment area. The Illinois EPA is 

responsible for air quality regulatory programs for every county in the state. 

Jurisdictional boundaries considered in this analysis are consistent with recommended 

geographic boundaries, or “county line” definitions, outlined in U.S. EPA’s guidance 

documentation. Sub-county boundaries in this study reflect 2009 Political Township 

boundaries provided by Property Tax Division of the Illinois Department of Revenue.

Illinois Air Quality

As recommended by U.S. EPA, the first step in identifying areas that are in violation of the 

revised SO2 NAAQS is to evaluate the most recent three years of ambient air monitoring 

data. Table 1 shows the most recent three consecutive years of quality assured air monitoring 

data for 2008 through 2010, along with the resulting design values. The design value is 

defined as the 3-year average of the annual 99th percentile daily maximum 1-hour SO2

concentrations collected at each monitor (which is generally the fourth highest daily 

maximum 1-hour concentration, averaged over three consecutive years). The general trend in 

annual 1-hour 99th percentile values statewide has been downward. Overall, 16 of the 19 

Illinois SO2 monitoring sites had 99th percentile values in 2010 that were lower than those 

same values in 2008. Despite the significant improvement in air quality statewide, four 

monitoring sites currently violate the revised SO2 NAAQS. These four monitors are located 

in Tazewell, La Salle, Cook, and Madison counties (see Figure 1). The remaining fifteen 

monitoring sites are attaining the revised SO2 NAAQS, most by a considerable margin. 
9

Table 1

2008-2010 Illinois SO2 Design Values (ppb)

AQS 

Code County Site Annual 99th Percentiles Design 

2008 2009 2010 Value

170310050 Cook Chicago - SE Police 35 19 21 25

170310063 Cook Chicago - CTA 26 21 14 20

170310076 Cook Chicago - Com Ed 26 24 20 23

170311601 Cook Lemont 97 114 90 100

170314002 Cook Cicero 43 29 31 34

170314201 Cook Northbrook 13 17 15 15

170990007 La Salle Oglesby 326 8 14 116

171150013 Macon Decatur 44 36 49 43

171170002 Macoupin Nilwood 20 16 15 17

171191010 Madison South Roxana 152 81 57 97

171193007 Madison Wood River WTP 67 46 54 56

171430024 Peoria Peoria 52 21 43 39

171570001 Randolph Houston 35 26 31 31

171630010 St. Clair East St. Louis 35 30 31 32

171670006 Sangamon Springfield 131 24 31 62

171790004 Tazewell Pekin 243 233 228 235

171850001 Wabash Mount Carmel 90 69 66 75

171851001 Wabash Rural Wabash Co. 57 53 59 56

171970013 Will Joliet 56 32 24 37
10

Figure 1
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Illinois 5 Factor Analysis

The U.S. EPA recommends that states consider the following five factors in assessing whether to 

depart from county boundaries as the designated nonattainment area boundary. As previously 

mentioned, Illinois has four counties where monitored violations of the revised SO2 NAAQS are 

occurring. The information in the following sections provides boundary recommendations based 

on the five factors outlined in U.S. EPA guidance within each violating county or adjacent 

county. 

Tazewell County

Air Quality

There are two SO2 monitors in the Peoria area. The first monitor is located west of the Illinois 

River in Peoria, while the second monitor is located east of the Illinois River in Pekin (see Figure 

2). Monitoring data for both sites is listed below in Table 2. The 2008-2010 design value for the 

Peoria monitor is below the revised 1-hour NAAQS, while the design value for the Pekin

monitor is well above the revised 1-hour NAAQS. The 2008 through 2010 annual 99th

percentiles show a small decrease at the Peoria site and consistently high values at the Pekin site. 

Table 2 – Peoria Area Air Quality Data for 2008-2010 (ppb)

AQS Code County Site Annual 99th Percentiles Design 

2008 2009 2010 Value

171430024 Peoria Peoria 52 21 43 39

171790004 Tazewell Pekin 243 233 228 235

Emissions 

Table 3 lists the major SO2 emission sources (reported SO2 emissions over 100 tons per year for 

at least one of the years from 2007 through 2009) within both Tazewell and Peoria counties. The 

locations of these sources are shown in Figure 2. From Figure 2, there are two sources in the 

vicinity of the violating monitor in Pekin: Aventine Renewable Energy, and Midwest Generation 

– Powerton. Overall, there has been a small decrease in SO2 emissions within the Peoria area 
12

during the period, however Aventine and Midwest Generation-Powerton, have shown either 

steady or increasing emissions trends during this period. 

Table 3 – Tazewell and Peoria County Reported SO2 Emissions for 2007-2009 

County ID Number Facility Name

Reported SO2 Emissions 

(Tons per Year)

2007 2008 2009

Tazewell 179060ACR Aventine Renewable Energy Inc 12239.93 11830.31 11819.57

Tazewell 179801AAA Midwest Generation – Powerton 20543.67 22355.08 22125.00

Peoria 143065AJE Archer Daniels Midland Co 3140.00 3049.00 2587.00

Peoria 143805AAG Ameren – Edwards 14535.90 11224.10 11734.40

Peoria 143808AAA Keystone Steel & Wire Co 109.26 137.53 86.61

Figure 2 – Location of Major SO2 Emission Sources in Tazewell and Peoria Counties
13

Meteorology

The closest National Weather Service (NWS) meteorological monitoring site to the Pekin area is 

located at the Greater Peoria Airport. The IEPA considers the meteorological characteristics of 

the airport site to generally be representative of the Tazewell County area, although it is possible 

that some local-scale differences may occur within the Illinois River valley, where Pekin is 

located. Figure 3 shows the climatological wind rose, or wind frequency distribution, for the 

Peoria Airport. The figure shows that southerly winds are most frequent in the Peoria area, with 

a secondary maximum from the northwest. 

Figure 3 - Greater Peoria Airport Climatological Wind Rose
14

Figure 4 shows the pollution rose for the Pekin monitor, which depicts the wind directions 

associated with measured SO2 concentrations exceeding 75 ppb at this location. Comparing the 

pollution rose in Figure 4 to Figure 5, which shows the locations of major SO2 emission sources 

with respect to the Pekin monitor, it is apparent that the wind direction during exceedance hours 

is either from the west or west-southwest, which aligns the nearby Aventine facility, and, to a 

lesser extent, Midwest Generation – Powerton with the monitor location.

Figure 4 – Pekin Pollution Rose
15

Figure 5 - Aerial Photo of the Pekin Monitor and nearby Facilities

Since the Pekin monitor is at a slightly higher elevation than the two facilities to the westsouthwest, IEPA believes that the high concentrations that are occurring at this monitor are 

primarily due to emissions from these local sources. 

Jurisdictional Boundaries

The Illinois EPA is responsible for air quality regulatory programs for every county in the state. 

Jurisdictional boundaries considered in this analysis are consistent with recommended geographic 

boundaries, or “presumptive boundary” definitions, outlined in U.S. EPA’s guidance documentation. 

Boundaries in this study reflect the 2009 political township boundaries provided by the Property Tax 

Division of the Illinois Department of Revenue. Based on the geographic location of Pekin and the 

individual sources, it is expected that the coordination of planning activities required to address the 

nonattainment designation can be carried out in a cohesive manner.
16

Recommendation

Based on the factors discussed above, Illinois recommends that Pekin and Cincinnati Townships 

in Tazewell County be designated as nonattainment for the 2010 1-hour SO2 NAAQS (see Figure 

6). These two townships contain both the violating monitor and the two most culpable emission 

sources.

Figure 6 – Proposed SO2 Nonattainment Area Boundary for Tazewell County 
17

La Salle County 

Air Quality

There is one SO2 monitor in La Salle County located in Oglesby. Monitoring data for this site is 

listed below in Table 4. The 2008-2010 design value for the Oglesby monitor currently exceeds 

the revised 1-hour NAAQS. However, the 2008 through 2010 annual 99th percentiles show a 

large decline in SO2 values measured at the Oglesby site related to the suspension of operations 

at the Lone Star Industries cement plant in 2008. The 99th percentiles for both 2009 and 2010 

were the lowest values in the state and the Oglesby monitor is expected to attain the revised 1-

hour NAAQS by the end of 2011. 

Table 4 – La Salle County Air Quality Data for 2008-2010 (ppb)

AQS Code County Site Annual 99th Percentiles Design 

2008 2009 2010 Value

170990007 La Salle Oglesby 326 8 14 116

Emissions 

Table 5 lists the major SO2 emission sources (reported SO2 emissions over 100 tons per year for 

at least one of the years from 2007 through 2009) in La Salle County. The locations of these 

sources are shown in Figure 7. From Figure 7, there is only one source in the vicinity of the 

violating monitor in Oglesby: Lone Star Industries. This facility has been closed since 2008, 

which is reflected in the large decrease in SO2 emissions shown in Table 5. There has also been 

a significant reduction in SO2 emissions at the Illinois Cement Company plant in La Salle, 

although this facility remains operational.

Table 5 – La Salle County Reported SO2 Emissions for 2007-2009 

County ID Number Facility Name

Reported SO2 Emissions 

(Tons per Year)

2007 2008 2009

La Salle 099030AAZ Illinois Cement Co 167.8 160.34 90.17

La Salle 099490AAD Owens-Brockway Glass Container Inc 228.24 221.72 208.69

La Salle 099816AAF Lone Star Industries Inc 2937.16 2241.18 0.00

La Salle 099825AAG Pilkington North America Inc 293.66 255.1 308.22
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Figure 7 – Location of Major SO2 Emission Sources in La Salle County

Meteorology

The Oglesby monitor is in north-central Illinois, roughly the same distance from NWS stations at 

the Rockford Airport and at the Peoria Airport. Figure 8 shows the climatological wind rose for 

the Rockford airport. The Rockford wind rose looks very similar to the Peoria wind rose, 

presented previously in Figure 3. There is a pronounced maximum frequency of southerly winds 

at Rockford, as at Peoria, with a secondary maximum from the northwest. The IEPA considers 

these NWS stations to generally be representative of conditions occurring in La Salle County, 

although it is recognized that the Vermillion River valley, where the Lone Star facility is located, 

may cause localized meteorological influences. 
19

Figure 8 - Greater Rockford Airport Climatological Wind Rose

Figure 9 shows the pollution rose for the Oglesby monitor, while Figure 10 is an aerial photo that 

shows the relationship of the one large source to the monitor. The pollution rose shows that the 

wind direction during exceedance hours is primarily from the southwest, which corresponds well 

with the location of Lone Star Industries, which is located to the south and southwest of the 

monitor. Based on this analysis, the IEPA concludes that exceedances of the revised 1-hour SO2

NAAQS at Oglesby are due primarily to emissions from the Lone Star facility.
20

Figure 9 – Oglesby Pollution Rose

Figure 10 - Aerial photo of the Oglesby Monitor and nearby Facility
21

Jurisdictional Boundaries

The Illinois EPA is responsible for air quality regulatory programs for every county in the state. 

Jurisdictional boundaries considered in this analysis are consistent with recommended geographic 

boundaries, or “presumptive boundary” definitions, outlined in U.S. EPA’s guidance documentation. 

Boundaries in this study reflect the 2009 political township boundaries provided by the Property Tax 

Division of the Illinois Department of Revenue. Based on the geographic location of Oglesby and 

the individual sources, it is expected that the coordination of planning activities required to address 

the nonattainment designation can be carried out in a cohesive manner.

Recommendation

Based on the factors discussed above, Illinois recommends that La Salle Township in La Salle 

County be designated as nonattainment for the 2010 1-hour SO2 NAAQS (see Figure 11). This 

township contains both the violating monitor and the most culpable source of SO2 emissions.

Figure 11 – Proposed SO2 Nonattainment Area Boundary for La Salle County
22

Cook and Will Counties

Air Quality

There are seven SO2 monitors located in Cook and Will Counties. Monitoring data for these

sites are listed below in Table 6. The 2008-2010 design values for all of the sites are well below 

the revised 1-hour NAAQS, except for the monitor at Lemont. As can been in Figure 12, the 

distribution of design values across northeastern Illinois indicates that the Lemont monitor 

represents a “hot spot” due to impacts from local emission sources.

Table 6 – Cook and Will County Air Quality Data for 2008-2010 (ppb)

AQS Code County Site Annual 99th Percentiles Design 

2008 2009 2010 Value

170310050 Cook Chicago - SE Police 35 19 21 25

170310063 Cook Chicago – CTA 26 21 14 20

170310076 Cook Chicago - Com Ed 26 24 20 23

170311601 Cook Lemont 97 114 90 100

170314002 Cook Cicero 43 29 31 34

170314201 Cook Northbrook 13 17 15 15

171970013 Will Joliet 56 32 24 37

Emissions 

Table 7 lists the major SO2 emission sources (reported SO2 emissions over 100 tons per year for 

at least one of the years from 2007 through 2009) within Cook and Will counties. The locations 

of these sources are shown in Figure 12. From Figure 12, there are three sources in the vicinity 

of the violating monitor in Lemont: Oxbow Midwest Calcining, CITGO Petroleum, and Midwest 

Generation – Will County. It should be noted that all three nearby sources are located in Will 

County, although the Lemont monitor is located in Cook County. Overall, SO2 emissions in 

Cook and Will counties have dropped by almost 50% since 2007, with the most significant 

reductions occurring at the two oil refineries (CITGO and Exxon Mobil). 
23

Table 7 – Cook and Will County Reported SO2 Emissions for 2007-2009 

County ID Number Facility Name

Reported SO2 Emissions 

(Tons per Year)

2007 2008 2009

Cook 031012ABI Corn Products International Inc 1942.00 2203.00 991.00

Cook 031069AAI Saint-Gobain Containers Inc 354.05 344.84 300.30

Cook 031123ABP Congress Development Co 57.43 81.33 204.00

Cook 031300AAJ Koppers Inc 846.80 823.17 705.38

Cook 031600ADY Carmeuse Lime Inc 359.57 321.46 0.00

Cook 031600AIN Midwest Generation - Crawford 8881.90 6626.90 7107.50

Cook 031600AMI Midwest Generation - Fisk 4954.51 4485.561 4217.56

Cook 031600CTF Saints Mary and Elizabeth Med. Center 0.07 0.10 125.01

Will 197090AAI CITGO Petroleum Corp 14170.75 6135.86 336.62

Will 197800AAA Exxon Mobil Oil Corp 22095.05 16404.03 1914.79

Will 197803AAK Oxbow Midwest Calcining LLC 7153.21 6204.85 4990.62

Will 197809AAO Midwest Generation – Joliet 20265.72 18281.72 17996.87

Will 197810AAK Midwest Generation - Will County 17310.81 16496.78 12602.53

Figure 12 – Location of Major SO2 Emission Sources in Cook and Will Counties
24

Meteorology

The Lemont monitor is located in Cook County, so the nearest NWS site is at Chicago’s O’Hare 

Airport. Since the Lemont site is a similar distance from Lake Michigan as O’Hare airport, the 

effect of Lake Michigan on local wind directions should be comparable. Figure 13 shows the 

climatological wind rose for O’Hare Airport. Unlike the Peoria and Rockford wind roses shown 

previously, a higher frequency of wind directions occur at O’Hare from southerly through 

westerly, with a secondary maximum from the northeast. 

Figure 13 – Chicago-O’Hare Airport Climatological Wind Rose
25

Figure 14 shows the pollution rose for the Lemont monitor, while Figure 15 is an aerial photo 

that shows the spatial relationship of major emission sources to the monitor. The pollution rose 

shows that the wind direction during exceedance hours is mostly from the west, which indicates 

likely contributions from Oxbow Midwest Calcining, and, to a lesser extent, CITGO Petroleum. 

With the close proximity of major sources upwind from the monitor on high concentration days, 

IEPA believes that nonattainment at the Lemont monitor is primarily due to these local sources.

Figure 14 - Lemont Pollution Rose
26

Figure 15 - Aerial photo of the Lemont monitor and nearby Facilities

Jurisdictional Boundaries

The Illinois EPA is responsible for air quality regulatory programs for every county in the state. 

Jurisdictional boundaries considered in this analysis are consistent with recommended geographic 

boundaries, or “presumptive boundary” definitions, outlined in U.S. EPA’s guidance documentation. 

Boundaries in this study reflect the 2009 political township boundaries provided by the Property Tax 

Division of the Illinois Department of Revenue. Based on the geographic location of Lemont and the 

individual sources, it is expected that the coordination of planning activities required to address the 

nonattainment designation can be carried out in a cohesive manner.

Recommendation

Based on the factors discussed above, Illinois recommends that Lemont Township in Cook 

County and DuPage and Lockport Townships in Will County be designated as nonattainment for 

the 2010 1-hour SO2 NAAQS (see Figure 16). These three townships contain both the violating 
27

monitor and the most culpable sources of SO2 emissions impacting the Lemont monitor.

Figure 16 – Proposed SO2 Nonattainment Area Boundary for Cook and Will Counties

Madison County

Air Quality

There are three SO2 monitors in the Metro-East area. Two of the monitors are located in western 

Madison County, while the third monitor is located in East St. Louis in St. Clair County. 

Monitoring data for all three sites is listed in Table 8. The 2008-2010 design values for the 

Wood River and East St. Louis monitors are well below the revised 1-hour NAAQS, while the 

design value for the South Roxana monitor exceeds the revised 1-hour NAAQS. The 2008 

through 2010 annual 99thpercentiles decreased at all three sites, with the most significant 

improvement occurring at the South Roxana monitor. 
28

Table 8 – Metro-East Area Air Quality Data for 2008-2010 (ppb)

AQS Code County Site Annual 99th Percentiles Design 

2008 2009 2010 Value

171191010 Madison South Roxana 152 81 57 97

171193007 Madison Wood River WTP 67 46 54 56

171630010 St. Clair East St. Louis 35 30 31 32

Emissions 

Table 9 lists the major SO2 emission sources (reported SO2 emissions over 100 tons per year for 

at least one of the years from 2007 through 2009) in Madison County. The locations of these 

sources are shown in Figure 17. From Figure 17, there is only one source in proximity to the 

violating monitor in South Roxana: ConocoPhillips. SO2 emissions in Madison County have 

decreased significantly during the 2007-2009 period. The largest reductions occurred at the 

ConocoPhillips oil refinery, which is located near the South Roxana monitor, and US Steel’s 

Granite City Works. 

Table 9 – Madison County Reported SO2 Emissions for 2007-2009 

County ID Number Facility Name

Reported SO2 Emissions 

(Tons per Year)

2007 2008 2009

Madison 119010AAE Alton Steel Inc 121.43 142.88 63.25

Madison 119020AAE Dynegy Midwest Gen. – Wood River 6462.30 6873.20 9089.10

Madison 119040ATN Gateway Energy & Coke Co LLC 0.00 0.00 580.34

Madison 119090AAA ConocoPhillips Co 13629.96 12273.72 5761.00

Madison 119813AAI US Steel - Granite City 6187.15 5612.67 1428.31
29

Figure 17 – Location of Major SO2 Emission Sources in Madison County

Meteorology

The nearest NWS site to Madison County is Lambert Field in St. Louis. Figure 18 shows the 

climatological wind rose for Lambert Field. Unlike the wind roses previously shown, the most 

frequent wind directions are from the south through southeast, with a strong secondary maximum 

from the northwest. The IEPA considers the meteorological conditions at Lambert Field to 

generally be representative of conditions occurring in Madison County, although it is recognized 

that the South Roxana monitor is located on the flood plain of the Mississippi River and may 

experience some localized differences. 
30

Figure 18 - St. Louis-Lambert Field Climatological Wind Rose

Figure 19 shows the pollution rose for the South Roxana monitor, while Figure 20 is an aerial 

photo that shows the relationship of the one large source to the monitor. The pollution rose 

shows that the wind direction during exceedance hours is primarily from the northwest which 

aligns the nearby ConocoPhillips refinery with the monitor location. With the proximity of this 

major nearby source to the monitor, IEPA concludes that emissions from this facility are 

primarily responsible for exceedances of the revised 1-hour SO2 NAAQS at South Roxana.
31

Figure 19 - South Roxana Pollution Rose

Figure 20 - Aerial photo of the South Roxana Monitor and nearby Facility
32

Jurisdictional Boundaries

The Illinois EPA is responsible for air quality regulatory programs for every county in the state. 

Jurisdictional boundaries considered in this analysis are consistent with recommended geographic 

boundaries, or “presumptive boundary” definitions, outlined in U.S. EPA’s guidance documentation. 

Boundaries in this study reflect the 2009 political township boundaries provided by the Property Tax 

Division of the Illinois Department of Revenue. Based on the geographic location of Roxana and the 

individual sources, it is expected that the coordination of planning activities required to address the 

nonattainment designation can be carried out in a cohesive manner.

Recommendation

Based on the factors discussed above, Illinois recommends that Chouteau and Wood River 

Townships in Madison County be designated as nonattainment for the 2010 1-hour SO2 NAAQS 

(see Figure 21). These two townships contain both the violating monitor and the most culpable 

source of SO2 emissions impacting the South Roxana monitor.

Figure 21 – Proposed SO2 Nonattainment Area Boundary for Madison County
33

Recommendations

IEPA’s recommendations for attainment/nonattainment boundary designations in Illinois for the 

2010 revised 1-hour SO2 national ambient air quality standard are contained in Table 10. 

Current air quality data collected by the IEPA indicates that the 2010 revised primary SO2

NAAQS is not being met in the areas listed in Table 10, and that they should be designated as 

nonattainment areas. The locations of IEPA’s recommended SO2 nonattainment areas for the 

State of Illinois are shown in Figure 22. 

The Clean Air Act does not specify the geographic boundaries, size, or the extent to which 

source contributions would require that an area be designated as nonattainment for the 2010 

revised primary SO2 standard, nor has U.S. EPA promulgated rules prescribing such. IEPA’s 

recommendations are consistent with the guidance memorandum provided by U.S. EPA and are 

based on an evaluation of current air quality, the location and magnitude of SO2 emission 

sources, and other factors. The IEPA recognizes that each of the factors considered in this 

evaluation, when evaluated individually, are not necessarily conclusive. Rather, IEPA’s 

recommendations are based on consideration of all of the factors taken together. It is expected 

that the coordination of planning activities required to address the nonattainment designations 

can be carried out in a cohesive manner. The data sources utilized in the preparation of this 

report are summarized in Table 11. 
34

Figure 22
35

Table 10

Recommended Attainment/Nonattainment Designations in Illinoisfor the 2010

Revised Primary 1-hour SO2 National Ambient Air Quality Standard

County (Partial) Designation Name of Area

Tazewell County:

Pekin and Cincinnati Townships

 Aux Sable Township

 Goose Lake Township

 All Other Townships

Nonattainment Tazewell County

Remainder of Tazewell County Unclassifiable

La Salle County:

La Salle Township Nonattainment La Salle County

Remainder of La Salle County Unclassifiable

Cook County:

Lemont Township Nonattainment Cook County

Remainder of Cook County Unclassifiable

Will County:

Lockport and DuPage Townships Nonattainment Will County

Remainder of Will County Unclassifiable

Madison County:

Chouteau and Wood River Townships Nonattainment Madison County

Remainder of Madison County Unclassifiable

All Other Counties Unclassifiable Illinois
36

Table 11

SO2 NAA Five Factor Documentation

Factor Data Analysis Data Source Date of Study

1. Air Quality SO2 2008-2010 Design Values 

at individual monitors 

(statewide)

IEPA BOA Database, 

Air Monitoring 

Section

2008-2010

2. Emissions Emission inventory information 

for SO2 

IEPA 2007-2009 

Reported Emissions, 2009

3. Geography/Topography Statewide elevations Google Maps Data 2008

4. Jurisdictional Boundaries Illinois Department of 

Revenue, Political Townships 

Illinois Department of 

Revenue, Property 

Tax Division, 

Springfield, Illinois

2009

5. Meteorology Weather patterns – Wind Roses 

and Pollution Roses.

1961 – 1990

National Weather 

Service, Illinois State 

Climatologist Office

October 7, 2004