Illinois 

Unclassifiable Area Designations for the 

2012 Primary Annual PM2.5 National Ambient Air Quality Standards 

Technical Support Document

1.0 Summary 

In accordance with section 107(d) of the Clean Air Act (CAA), the EPA must promulgate 

designations for all areas of the country. In particular, the EPA must identify those areas that are 

violating a National Ambient Air Quality Standard (NAAQS) or contributing to a violation of the 

NAAQS in a nearby area. The EPA identifies these areas as “nonattainment” areas. Additionally, 

through the designation process, the EPA identifies areas that are meeting the NAAQS and those 

areas without sufficient data for the Agency to make a determination. The EPA uses a 

designation category of "unclassifiable/attainment" for areas where air quality monitoring data 

indicate attainment of the NAAQS and for areas that do not have monitors but for which the 

EPA has reason to believe are likely to be in attainment and are not contributing to nearby 

violations. The EPA reserves the category of "unclassifiable" for areas where the EPA cannot 

determine based on available information whether the area is meeting or not meeting the 

NAAQS or where the EPA has not determined that the area contributes to a nearby violation. 

The EPA must complete the initial area designation process within 2 years of promulgating a 

new or revised NAAQS, or may do so within 3 years under certain circumstances.1 This 

Technical Support Document (TSD) describes the EPA’s intent to designate certain areas in 

Illinois as unclassifiable for the 2012 primary annual fine particle NAAQS (2012 annual PM2.5

NAAQS).2 

Under section 107(d), states are required to submit area designation recommendations to the 

EPA for the 2012 annual PM2.5 NAAQS no later than 1 year following promulgation of the 

NAAQS, or by December 13, 2013. On December 12, 2013, Illinois recommended that specified 

counties and portions of counties in the Illinois portions of the Chicago and St. Louis areas be 

designated as nonattainment, and that the remaining counties and portions of counties in the state 

be designated attainment/unclassifiable for the 2012 annual PM2.5 NAAQS, based on air quality 

data from 2010 to 2012. Also on December 12, 2013, Indiana recommended that no counties 

within the state be designated nonattainment, and Indiana specifically recommended designating 

Lake, Porter, and LaPorte Counties as attainment based on monitoring data recorded within those 

 

1

 Section 107(d) of the CAA requires the EPA to complete the initial designation process within 2 years of 

promulgation of a new or revised NAAQS, unless the Administrator has insufficient information to make initial 

designation decisions in the 2-year time frame. In such circumstances, the EPA may take up to 1 additional year to 

make initial area designation decisions (i.e., no later than 3 years after promulgation of the standard).

2

 On December 14, 2012, the EPA promulgated a revised primary annual PM2.5 NAAQS (78 FR 3086, January 15, 

2013). In that action, the EPA revised the primary annual PM2.5 standard, strengthening it from 15.0 micrograms per 

cubic meter (μg/m3

) to 12.0 μg/m3.
counties. On December 10, 2013, Missouri recommended that no portion of Missouri be 

included in the St. Louis area and that all of the state be designated attainment/unclassifiable. 

However, a recent EPA-conducted technical systems audit of the weighing of PM2.5 samples in 

Illinois revealed that the Cook County Department of Environmental Control, which weighs all 

of the filters in Illinois’ monitoring network, did not have appropriate equipment for determining 

whether the laboratory conditions met the temperature and humidity criteria in 40 CFR 50 

Appendix L for proper conditioning of filters, and the instantaneous temperature and humidity 

information suggested that many of the weighings failed to meet these criteria.3 As a result, the 

EPA believes that no site in Illinois has sufficient valid data to support a determination of either 

nonattainment or attainment. Thus, the EPA cannot determine whether any area in Illinois is 

meeting or not meeting the NAAQS. Furthermore, EPA cannot rely upon analyses the states 

performed which partially rely upon this invalid monitoring data. Because the EPA cannot make 

a final regulatory determination about whether a violation exists, in some cases the EPA is also 

not able to determine whether counties nearby to those counties with incomplete monitoring data 

contribute to a nearby violation. Consequently, the EPA intends to designate all of the affected 

areas as “unclassifiable.” 

After considering Illinois’, Indiana’s, Iowa’s and Missouri’s recommendations and based on the 

EPA’s assessment of available information as described in this TSD, EPA intends to designate 

the areas identified in Table 1 as unclassifiable for the 2012 annual PM2.5 NAAQS at this time. 

The CAA provides the EPA with discretion regarding whether and when to initiate a 

redesignation process. The EPA may consider air quality data, planning and control 

considerations, or any other air quality-related considerations the Administrator deems 

appropriate. As a result, the boundaries of any future actions may not be those that EPA uses to 

define the unclassifiable areas that EPA intends to promulgate now based on incomplete data. 

Table 1. EPA’s Intended Unclassifiable Areas for the 2012 annual PM2.5 NAAQS 

Area States’ Recommendations EPA’s Intended Unclassifiable 

Counties 

 

3

 Memorandum dated August 14, 2014 from Liz Naess, Group Leader, Air Quality Analysis Group, US EPA Office 

of Air Quality Planning and Standards, to EPA Docket EPA-HQ-OAR-2012-0918, Air Quality Designations for the 

2012 PM2.5 Standards, titled, “Data Quality Issues in Illinois Affecting Air Quality Designations for the 2012 

PM2.5National Ambient Air Quality Standard.” 
Chicago, IL-IN 

Illinois - Nonattainment for: 

 Cook County 

 DuPage County 

 Kane County 

 Lake County 

 McHenry County 

 Will County 

 Grundy County (part) 

 Kendall County (part) 

Indiana: 

 Attainment 

Illinois: 

 Cook County 

 DuPage County 

 Kane County 

 Lake County 

 McHenry County 

 Will County 

 Grundy County (part) 

 Kendall County (part) 

Indiana: 

 Lake County 

 Porter County

St. Louis, IL-MO 

Illinois – Nonattainment for: 

 Madison County 

 Monroe County 

 St. Clair County 

 Randolph County (part) 

Missouri: 

 Unclassifiable/Attainment for all

counties 

Illinois: 

 Madison County 

 Monroe County 

 St. Clair County 

 Randolph County (part) 

Missouri: 

 St. Louis City 

 St. Louis County 

 St. Charles County 

 Jefferson County 

 Franklin County

Davenport-Moline-Rock 

Island, IL-IA

Illinois – 

Unclassifiable/Attainment for: 

 Rock Island County 

 Henry County 

 Mercer County 

Iowa – Unclassifiable/Attainment 

for: 

 Scott County 

Illinois: 

 Rock Island County 

 Henry County 

 Mercer County 

Iowa: 

 None - Scott County to be designated 

Unclassifiable/attainment 

Remainder of Illinois Unclassifiable/Attainment Unclassifiable 

Chicago Area 

 

Chicago is the primary city of a three-state MSA that includes fourteen counties: nine counties in 

Illinois, four counties in Indiana, and one county in Wisconsin. The consolidated statistical area 

(CSA) of which Chicago is the central city includes three additional MSAs (Kankakee, Michigan 

City-LaPorte, and Ottawa-Peru) with an additional five counties. The urbanized portion of this 

area includes substantial portions of the Chicago-Naperville-Elgin MSA, but the outer MSAs do 

not contain significant urbanization as compared to the central Chicago area. The Chicago area 

was designated nonattainment for the 1997 PM2.5 NAAQS. Based on analysis of air quality, 

emissions, meteorological data, and other factors considering in determining those prior 

designations, EPA promulgated a Chicago, IL-IN nonattainment area that includes almost the 

entirety of the Chicago-Naperville-Arlington Heights Metropolitan Division (Cook, Dupage, 
McHenry, and Will Counties along with portions for Grundy and Kendall Counties) along with 

selected counties from adjoining Metropolitan Divisions of this MSA (Kane County from the 

Elgin area, Lake and Porter Counties from the Gary, Indiana area, and Lake County, Illinois 

from the Lake County-Kenosha County area). There are attaining monitors in Lake, Porter, and 

LaPorte Counties in Indiana and in Kenosha County in Wisconsin, as shown in Table 2. No data 

for Illinois are shown in Table 2 because no site in Illinois has sufficiently complete data for 

computing a reliable design value. 

Table 2. Air Quality Data collected at Regulatory Monitors (all DV levels in μg/m3)

a

County, 

State 

Monitor 

Site ID 

State Rec 

NA? 

09-11 

DV 

10-12 

DV 

11-13 

DV 

Lake, IN 18-089-0006 No 11.7 11.5 10.8 

Lake, IN 18-089-0027 No 11.5 11.8 11.2 

Lake, IN 18-089-0031 No 12.4 12.2 11.6 

Lake, IN 18-089-2004 No 13.1 11.4 10.8 

Lake, IN 18-089-2010 No 11.1 11 10.6 

LaPorte, IN 18-091-0011 No 10.2 10.1 9.6 

Porter, IN 18-127-0024 No 11.1 10.7 10.4 

Kenosha, WI 55-059-0019 No 9.7 9.5 9.1 

aWhere a county has more than one monitoring location, the county design value is indicated in red type. 

 

The TSD for the EPA’s designation of the Chicago area for the 1997 standard provided an 

extensive review of air quality data, emissions data, population, motor vehicle travel, 

meteorology, and other related factors. While the Illinois air quality data are not sufficiently 

complete to provide a reliable indication of the magnitude of concentrations, the available air 

quality data suggest that the spatial distribution of exposure to PM2.5 is similar to the distribution 

EPA found in 2005, when it promulgated the Chicago 1997 PM2.5 nonattainment area. 

Furthermore, a review of the distribution of emissions, population, and vehicle travel also shows 

a similar distribution of these parameters, in both cases showing the greatest quantity of 

emissions, population, and vehicle travel in Cook County but showing substantial quantities of 

each of these parameters in the same list of surrounding counties. This review therefore suggests 

that if the Chicago area is violating the NAAQS, the area that the EPA finds would likely be 

contributing to that violation would likely be the same area as EPA found in 2005 to contribute 

to violations of the 1997 PM2.5 NAAQS. 

Based on this analysis, the EPA intends to designate a Chicago, IL-IN unclassifiable area that 

includes the same area as was designated nonattainment for the 1997 PM2.5 NAAQS. Thus, the 

EPA intends to designate an unclassifiable area that includes Cook, Dupage, Kane, Lake, 

McHenry, and Will Counties as well as Aux Sable and Goose Lake Townships in Grundy County and 

Oswego Township in Kendall County in Illinois, and Lake and Porter Counties in Indiana. Other 

portions of Indiana are addressed in a TSD for the Louisville area, and the EPA intends to 

designate the remainder of Indiana as unclassifiable/attainment. 
St. Louis Area 

 

St. Louis is the primary city of a two-state MSA that includes the City of St. Louis and fifteen 

counties: the City of St. Louis and seven counties in Missouri, and eight counties in Illinois. The 

consolidated statistical area (CSA) of which St. Louis is the central city includes two additional 

MSAs (Centralia, Illinois, and Farmington, Missouri) with an additional two counties. The 

urbanized portion of this area includes substantial portions of the St. Louis MSA, but the outer 

MSAs do not contain significant urbanization relative as compared to the central St. Louis area. 

The St. Louis area was designated nonattainment for the 1997 PM2.5 NAAQS. Based on analysis 

of air quality, emissions, meteorological data, and other factors considering in determining those 

designations, EPA promulgated a St. Louis, IL-MO nonattainment area that included the urban 

core of this area, including the City of St. Louis and four counties in Missouri and three counties 

plus a portion of a fourth county in Illinois. There are attaining monitors in Franklin, Jefferson, 

St. Louis, and St. Charles Counties and St. Louis City, as shown in Table 3. No data for Illinois 

are shown in Table 2 because no site in Illinois has sufficiently complete data for computing a 

reliable design value. 

Table 3. Air Quality Data collected at Regulatory Monitors (all DV levels in μg/m3)

a

County, State Monitor 

Site ID 

State Rec 

NA? 

09-11 

DV 

10-12 

DV 

11-13 

DV 

Franklin, MO N/A No No monitor 

Jefferson, MO 290990019 No 10.3 10.1 9.8 

St. Louis, MO 291893001 No 10.9 10.9 

St. Louis City, MO 295100085 No 12 11.7 11.1 

St. Charles, MO N/A No No monitor 

aWhere a county has more than one monitoring location, the county design value is indicated in red type. 

The TSD for EPA’s designation of the St. Louis area for the 1997 standard provided an extensive 

review of air quality data, emissions data, population, motor vehicle travel, meteorology, and 

other related factors. While the Illinois air quality data are not sufficiently complete to provide a 

reliable indication of the magnitude of concentrations at this time, the available air quality data 

suggest that the spatial distribution of exposure to PM2.5 is similar to the distribution EPA found 

in 2005, when it promulgated the St. Louis 1997 PM2.5 nonattainment area. Furthermore, a 

review of the distribution of emissions, population, and vehicle travel also shows a similar 

distribution of these parameters, with St. Louis County having approximately a fourth of the 

emissions of the various relevant pollutants and more than a fourth of the area’s population and 

vehicle travel, and other surrounding counties in Missouri and Illinois and the City of St. Louis 

also having significant nearby emissions, population and vehicle travel. This review therefore 

suggests that if the St. Louis area is violating the NAAQS, the area that EPA finds would likely 
be contributing to that violation would likely be the same area as EPA found in 2005 to 

contribute to violations of the 1997 PM2.5 NAAQS. 

In conjunction with its recommendations, Missouri submitted extensive documentation intended 

to demonstrate that occasions when the Granite City monitor in Illinois exceeds the NAAQS, the 

Missouri portion of the St. Louis area should not be considered to contribute to those occurrences 

of elevated concentrations. While this monitor has historically recorded the highest 

concentrations in the area, Missouri’s analysis is tied to particular measurements at this monitor, 

many of which the EPA has subsequently found to be unreliable. Therefore, this TSD does not 

provide a detailed review of Missouri’s analysis. Furthermore, all data collected during the year 

are important when determining contributions to an annual standard such as the 2012 annual 

PM2.5 NAAQS. Compliance with an annual NAAQS is dependent upon monitor readings 

throughout the year, including days with monitored ambient concentrations below the level of 

the NAAQS. For the 2012 annual PM2.5 NAAQS, the annual mean is calculated as the mean of 

quarterly means. A high quarter can heavily influence the mean for an entire year, which, in turn, 

can contribute to an elevated 3-year design value. When 3 consecutive years of quality assured, 

certified data are available for the St. Louis, IL-MO area intended PM2.5 unclassifiable area, 

Illinois, Missouri or the EPA may initiate the redesignation process. The CAA provides the EPA 

with discretion regarding whether and when to initiate a redesignation process. The EPA may 

consider air quality data, planning and control considerations, or any other air quality-related 

considerations the Administrator deems appropriate. As a result of these potential future 

analyses, the boundaries of any potential future nonattainment area may not the same as the 

intended boundary for the St. Louis, MO-IL unclassifiable area. 

Based on this analysis, we are preliminarily recommending designating a St. Louis, MO-IL 

unclassifiable area that includes the same area as was designated nonattainment for the 1997 

PM2.5 NAAQS. Thus, the EPA intends to designate an unclassifiable area that includes St. Louis 

City and Franklin, Jefferson, St. Charles, and St. Louis Counties in Missouri and Madison, 

Monroe, and St. Clair Counties and Baldwin Township in Randolph County in Illinois. The EPA 

intends to designate all other portions of Missouri as unclassifiable/attainment. 

Davenport-Moline-Rock Island, IA-IL

The Davenport- Moline-Rock Island, IA-IL MSA includes Rock Island, Henry and Mercer 

Counties in Illinois and Scott County in Iowa. Both Illinois and Iowa recommended the four 

counties within this area as unclassifiable/attainment. The core of the urban area of Davenport, 

where the majority of the emissions and emissions activities are located, consists of Scott 

County, Iowa and Rock Island County, Illinois. 

As explained above, the EPA is designating all of Illinois unclassifiable at this time. However, 

the EPA needs to evaluate whether the Iowa portion of the Davenport-Moline-Rock Island, IAIL MSA could be contributing to any potential violations of the NAAQS in the Illinois portion of 

this MSA. To do so, the EPA has considered information relevant to the five factor analysis for 

the Iowa portion of the MSA. Below is a brief discussion of the information pertaining to the five 
factors generally considered for a nonattainment area, including air quality data, emissions data, 

meteorology, population, and jurisdictional boundaries. [Additional analyses for the DavenportMoline-Rock Island, IA-IL MSA are provided in EPA Docket No. EPA-HQ-OAR-2012-0918, 

Air Quality Designations for the 2012 PM2.5 Standards.4 ] 

For the first factor, the EPA considers air quality information for the area. The Iowa portion of 

the Davenport area currently has four PM2.5 monitors located in Scott County, Iowa. All four 

monitors have complete data showing attainment of the 2012 PM2.5 NAAQs, with 2011-2013 

design values ranging from 10.2 to 10.7 μg/m3. As noted above, the EPA does not have reliable 

monitor data for the monitor located in Rock Island County, Illinois. The Rock Island County 

monitor has historically measured annual values below the Scott County, Iowa monitors, but 

given the questions concerning the validity of the monitor data the EPA cannot place too much 

reliance on this fact. Table 4 shows the 2013 design values for the four Iowa monitors located in 

Scott County. 

Table 4. Air Quality Data collected at Regulatory Monitors in Davenport (all DV levels in μg/m3) 

State County Monitor ID 

State 

Recommended 

Nonattainment? 

PM2.5 Annual 

Design Value 

2009-2011 

PM2.5 Annual 

Design Value 

2010-2012 

PM2.5 Annual 

Design Value 

2011-2013 

Iowa Scott 191630015 No 11.4 11.0 10.2 

Iowa Scott 191630018 No 11.5 11.2 10.4 

Iowa Scott 191630020 No 11.3 10.7 

Iowa Scott 191630019 No 10.6 

Historically, the Davenport area has not violated any annual PM2.5 standards, and thus the EPA 

has not previously established any nonattainment boundary for this area. . In the absence of a 

previously established nonattainment boundary, the EPA has considered relevant information to 

assess the possibility of contribution to a potential violation of the NAAQS in the Illinois portion 

of the MSA. 

A review of population data shows an approximate equal split on each side of the respective state 

lines, with 2010 Rock Island County population of 147,612 and 2010 Scott county population of 

165,781. While Henry and Mercer have an additional population of 66,850 combined, the 

population density in these counties is much less than the two core counties of Rock Island and 

Scott. 

Looking at the emissions data in the Davenport area the EPA notes that there are several sizable 

point sources in the area, including a power plant in Scott County (MidAmerican Energy 

Riverside Station). Additional point sources of note include Alcoa (located north and east of all 

monitors in Scott County), as well as Lafarge North America (located in the Southwest portion 

 

4

 Preliminary Technical Support Document, August 2014, titled, Davenport-Moline-Rock Island, IL-IA Area

Designation for the 2012 Primary Annual PM2.5 National Ambient Air Quality Standard Technical Support 

Document, prepared by the Region 7 US EPA. 
of Scott County), and the John Deere facility (located in Rock Island County south of the 

MidAmerican Energy plant noted above.) Emissions from each of these stationary sources is 

relatively low, with the highest being approximately 1,511 tons per year of NOx and 3,694 tons 

per year of SO2 from the MidAmerican Energy Riverside Station. 

Overall emissions are similar in the Iowa and Illinois counties in the Davenport area with 

population related and mobile source emissions in the core areas at the same order of magnitude. 

The aggregate emissions of direct PM2.5 and precursor pollutants from the point sources 

mentioned above are slightly higher in Scott County, but are generally from sources located in an 

area which would be less likely to impact the Rock Island County portion of the Davenport area, 

based on the meteorological data. 

A review of the meteorological data for the Davenport area indicates winds most frequently from 

the south, east and west with a smaller northwest component. Although the wind data suggests 

that there could be contribution from sources in Scott County to potential violations of the 

NAAQS in the Rock Island portion of the Davenport area, much of the emissions and emissions 

activity in Scott County comes from sources located to the north and northeast of the monitor in 

Rock Island and thus there is less likely to be contribution from such sources. 

Based on this technical analysis, the EPA agrees with Iowa’s recommendation and we intend to 

designate Scott County, Iowa as unclassifiable/attainment with the remaining three counties in 

Illinois (Rock Island, Henry and Mercer) designated as unclassifiable. The EPA intends to 

designate all other counties in Iowa as unclassifiable/attainment as recommended by Iowa.