Attachment 1

Illinois Area Designations For the 

24-Hour Fine Particle National Ambient Air Quality Standard

The table below identifies the counties in Illinois that EPA has
designated as not attaining the 2006 24-hour fine particle (PM2.5)
standard.  A county or part thereof is designated as nonattainment if it
has an air quality monitor that is violating the standard or if the
county is determined to be contributing to the violation of the
standard. 

 

Area 	Illinois Recommended Nonattainment Counties	EPA’s Designated
Nonattainment Counties

Chicago-Gary-Kenosha, IL-IN-WI	Cook

DuPage

Kane

Lake

McHenry

Will

Grundy* (partial)

Kendall* (partial)	Cook

DuPage

Kane

Lake

McHenry

Will

Grundy* (partial)

Kendall* (partial)

Davenport-Rock Island-Moline, IA-IL	None	Rock Island* (partial)

Paducah-Mayfield, KY-IL	None	Massac* (partial)

Saint Louis, MO-IL	Madison

Monroe

Saint Clair

Randolph* (partial)	Madison

Monroe

Saint Clair

Randolph* (partial)

* Illinois recommended a slightly smaller partial county area, excluding
a portion of Baldwin Township from the nonattainment area.  EPA is
designating the entire township as nonattainment.  The other Illinois
partial county boundaries are Grundy- Aux Sable and Goose Lake
Townships, Kendall- Oswego Township, Rock Island- Black Hawk, Coal
Valley, Hampton, Moline, Rock Island, South Moline, and South Rock
Island Townships, and Massac- Hillerman Precinct. 

EPA Technical Analysis for Chicago-Gary-Kenosha, IL-IN-WI 

EPA reviewed relevant information for the ten counties including eight
Illinois counties partly or fully within the area designated
nonattainment for the 1997 standards as well as for surrounding
counties.  There are violating monitors in Cook and Will Counties and in
Lake County, Indiana.  Illinois recommended a definition of the
nonattainment area for the 2006 standards that reflects the same
boundaries as were established for the 1997 standards, including Cook,
Du Page, Kane, Lake, Mc Henry, and Will counties, Aux Sable and Goose
Lake Townships in Grundy County, and Oswego Township in Kendall County. 
EPA agrees with this recommendation.  

EPA also examined information for other counties within and adjacent to
the Combined Statistical Area as well as for adjacent counties.  The
bulk of emissions and population are captured without including DeKalb,
Grundy, Kankakee, and Kendall Counties, since these counties have
limited emissions and population.  Nevertheless, we support the
recommendation by the Illinois EPA to include the three townships in
Grundy and Kendall counties in the nonattainment area to maintain
consistency with the ozone designations and the prior PM2.5 designations
and thereby facilitate planning, as well as to include slightly more
emissions in the planning area.  

Emissions for other surrounding counties are relatively low, and no
other factor warranted designating these counties nonattainment.  

Figure 1 is a map of the counties in the nonattainment area and other
relevant information such as the locations and design values of air
quality monitors, and the metropolitan area boundary. 

 

Figure 1

For this area, EPA previously established PM2.5 nonattainment boundaries
for the 1997 PM2.5 NAAQS that included ten full and partial counties,
with eight being located in Illinois and two in Indiana.

In its December 18, 2007 letter, Illinois recommended that the same full
and partial counties in the Chicago area be designated as
“nonattainment” for the 2006 24-hour PM2.5 standard based on air
quality data from 2004-2006.  These data are from Federal Reference
Method (FRM) monitors located in the state.  Indiana recommended Lake
County be designated as “nonattainment” for the 2006 24-hour PM2.5
standard based on air quality data in its May 30, 2008 letter.

In August 2008, EPA notified Illinois and Indiana of its intended
designations.  In this letter, EPA also requested that if the State
wished to provide comments on EPA’s intended designation, it should do
so by October 20, 2008.  EPA stated that it would consider any
additional information (e.g., on power plants or partial county areas)
provided by the state in making final decisions on the designations. 
Illinois did not provide any updates for its portion of the Chicago
nonattainment area.  

Based on EPA's technical analysis described below, EPA has designated
six full and two partial counties in Illinois and two Indiana counties
as nonattainment for the 24-hour PM2.5 air-quality standard as the
Chicago nonattainment area, based upon currently available information. 
These counties are listed in the table below.

The following is a review of data for relevant factors for the Chicago
area.

Factor 1:  Emissions data

For this factor, EPA evaluated county level emission data for the
following PM2.5 components and precursor pollutants:  “PM2.5 emissions
total,” “PM2.5 emissions carbon,” “PM2.5 emissions other,”
“SO2,” “NOx,” “VOCs,” and “NH3.”  “PM2.5 emissions
total” represents direct emissions of PM2.5 and includes:   “PM2.5
emissions carbon,” “PM2.5 emissions other”, primary sulfate (SO4),
and primary nitrate.  (Although primary sulfate and primary nitrate,
which are emitted directly from stacks rather than forming in
atmospheric reactions with SO2 and NOx, are part of “PM2.5 emissions
total,” they are not shown in Table 1 as separate items).  “PM2.5
emissions carbon” represents the sum of organic carbon (OC) and
elemental carbon (EC) emissions, and “PM2.5 emissions other”
represents other inorganic particles (crustal).  Emissions of SO2 and
NOx, which are precursors of the secondary PM2.5 components sulfate and
nitrate, are also considered.  VOCs (volatile organic compounds) and NH3
(ammonia) are also potential PM2.5 precursors and are included for
consideration. 

Emissions data were derived from the 2005 National Emissions Inventory
(NEI), version 1.  See
http://www.epa.gov/ttn/naaqs/pm/pm25_2006_techinfo.html.

EPA also considered the Contributing Emissions Score (CES) for each
county.  The CES is a metric that takes into consideration emissions
data, meteorological data, and air quality monitoring information to
provide a relative ranking of counties in and near an area.  Note that
this metric is not the exclusive manner for considering data for these
factors.  A more detailed description can be found at
http://www.epa.gov/ttn/naaqs/pm/pm25_2006_techinfo.html#B.

Table 1 shows emissions of PM2.5 and precursor pollutants components
(given in tons per year) and the CES for violating and potentially
contributing counties in the Chicago area.  Counties that are part of
the Chicago nonattainment area for the 1997 PM2.5 NAAQS are shown in
boldface.  Counties are listed in descending order by CES.

Table 1.  PM2.5 24-hour Component Emissions, and CESs 

County	State Recommended Nonattainment?	CES	PM2.5

emissions 

total	PM2.5

emissions 

carbon	PM2.5

emissions 

other	SO2

	NOx	VOCs	NH3

Cook, IL	Yes	100	10,081	5,407	4,674	35,354	175,267	152,288	4,550

Lake, IN	No	100	7,079	1,219	5,861	39,500	54,203	24,679	3,784

Will, IL	Yes	95	5,432	1,236	4,195	78,792	46,028	19,886	1,407

Porter, IN	No	41	3,901	719	3,183	24,458	29,930	9,795	909

DuPage, IL	Yes	16	2,075	1,259	816	2,013	36,880	29,541	1,385

Jasper, IN	No	14	2,641	280	2,360	40,723	20,104	3,367	2,929

Kankakee, IL	No	9	1,660	419	1,242	366	7,351	6,830	1,699

Kane, IL	Yes	4	1,997	733	1,263	1,037	16,528	15,578	1,293

Grundy, IL	Partial	3	1,105	248	857	362	4,057	4,223	1,027

Lake, IL	Yes	3	2,657	1,070	1,587	14,719	29,478	32,778	747

Kendall, IL	Partial	2	811	230	581	351	3,697	3,693	753

McHenry, IL	Yes	1	2,102	634	1,468	592	9,493	10,596	1,224

Kenosha, WI	No	1	1,489	460	1,030	33,988	15,967	7,857	647



Table 2 provides the data for CES weighting factors.  The trajectory
factors are used in CES calculations to account for seasonal
meteorology.  For the top 10% of days in both the cold and warm seasons,
wind trajectories were run for a 48 hour period preceding the high
monitor reading.  The amount of time the air mass was over a county
within the mixing height was calculated.  The values were scaled so that
the maximum value is 100.  Thus, the county that is most likely to be
upwind of a monitor on a high concentration day in a season is given a
score of 100.  The scores for the other counties will reflect the
relative likelihood of being upwind.  As the concentration of a
pollutant will decrease as it goes further downwind, a distance
weighting factor is also used in calculating the CES.  The distance
factor listed on Table 2 provides the distance from the center of a
county to the center of the violating county.  If a county is violating,
the distance used is the average distance from the center to the county
line.

  Table 2.  CES Factor Data

County	CES	Trajectory Factor- Cold	Trajectory Factor- Warm	Distance (mi)

Cook, IL	100	97	72	15.8

Lake, IN	100	100	100	32.5

Will, IL	95	92	68	25.0

Porter, IN	41	84	87	42.4

DuPage, IL	16	81	50	17.5

Jasper, IN	14	58	69	64.9

Kankakee, IL	9	72	60	46.6

Kane, IL	4	42	17	36.1

Grundy, IL	3	56	28	50.1

Lake, IL	3	35	8	37.9

Kendall, IL	2	58	28	38.1

McHenry, IL	1	19	4	50.5

Kenosha, WI	1	15	1	55.4



Within Illinois, emissions are highest in Cook, Will, DuPage, Lake,
Kane, and McHenry Counties.  The emissions from Kankakee, Grundy, and
Kendall Counties are moderate.  Based on emission levels and CES values,
eight Illinois counties are candidates for a 24-hour PM2.5 nonattainment
designation.

Factor 2:  Air quality data 

This factor considers the 24-hour PM2.5 design values (in µg/m3) for
air quality monitors in counties in the Chicago area based on data for
the 2005-2007 period.  A monitor’s design value indicates whether that
monitor attains a specified air quality standard.  The 24-hour PM2.5
standards are met when the 3-year average of a monitor’s 98th
percentile values are 35 µg/m3 or less.  A design value is only valid
if minimum data completeness criteria are met. 

The 24-hour PM2.5 design values for counties in the Chicago area are
shown in Table 3.

	Table 3.  Air Quality Data

County	State 

Recommended

Nonattainment?	Design Values

2004-2006	Design Values

2005-2007

Cook, IL	Yes	42	40

Lake, IN	No	38	37

Will, IL	Yes	36	37

Porter, IN	No	31	32

DuPage, IL	Yes	33	35

Kane, IL	Yes	32	35

Grundy, IL	Partial



Lake, IL	Yes	33	35

Kendall, IL	Partial



McHenry, IL	Yes	31	31



Three counties, Cook and Will in Illinois and Lake in Indiana, show
violations of the 24-hour PM2.5 standard.  Therefore, these counties are
included in the Chicago nonattainment area.  However, the absence of a
violating monitor alone is not a sufficient reason to eliminate counties
as candidates for nonattainment status.  Each county has been evaluated
based on the weight of evidence of the nine factors and other relevant
information.

For purposes of its review, EPA used data available from the Chemical
Speciation Network and the Interagency Monitoring of Protected Visual
Environments (IMPROVE) network to estimate the composition of fine
particle mass on days with the highest fine particle concentrations. 
Analysis of these data indicates that the days with the highest fine
particle concentrations in the Chicago area occur about 47% in the warm
season and 53% in the cool season.  In the warm season, the average
chemical composition of the highest days is 72% sulfate, no nitrate, 25%
carbon, and 3% crustal.  In the cool season, the average chemical
composition of the highest days is 21% sulfate, 39% nitrate, 38% carbon,
and 2% crustal.  These data indicate that sources of SO2, NOx, and
direct PM2.5 emissions contribute to violations in the area.  

Note:  Eligible monitors for providing design value data generally
include State and Local Air Monitoring Stations (SLAMS) at
population-oriented locations with an FRM  monitor.  All data from
Special Purpose Monitors (SPM) using an FRM is eligible for comparison
to the relevant NAAQS, subject to the requirements given in the October
17, 2006 Revision to Ambient Air Monitoring Regulations (71 FR 61236). 
All monitors used to provide data must meet the monitor siting and
eligibility requirements given in 71 FR 61236 to 61328 in order to be
acceptable for comparison to the 24-hr PM2.5 NAAQS for designation
purposes.

Factor 3: Population density and degree of urbanization (including
commercial development)

Table 4 shows the 2005 population for each county in the area being
evaluated, as well as the population density for each county in that
area.  Population data gives an indication of whether it is likely that
population-based emissions might contribute to violations of the 24-hour
PM2.5 standards. 

Table 4.  Population

County	State Recommended Nonattainment?	2005 Population	2005 Population
Density (pop/mi2)

Cook, IL	Yes	 5,303,943 	5545

Lake, IN	No	    491,706 	980

Will, IL	Yes	    642,625 	758

Porter, IN	No	    157,408 	375

DuPage, IL	Yes	    931,219 	2769

Kane, IL	Yes	    483,208 	923

Grundy, IL	Partial	     43,736 	102

Lake, IL	Yes	    704,086 	1504

Kendall, IL	Partial	     79,597 	247

McHenry, IL	Yes	    304,701 	499

Kankakee	No	    107,824	158



Within Illinois, the counties with the greatest population are Cook,
DuPage, Lake, Will, Kane, and McHenry Counties.  The populations and
population densities of Kankakee, Grundy, and Kendall Counties are
significantly lower.

In the Indiana portion of the Chicago area, Lake County has a sizable
population and population density.  Both are more moderate in Porter
County, but still larger that other area counties designated as
nonattainment. 

Factor 4: Traffic and commuting patterns 

This factor considers the number of commuters in each county who drive
to another county within the Chicago area, the percent of total
commuters in each county who commute within the area, as well as the
total Vehicle Miles Traveled (VMT) for each county in millions of miles
(see Table 5).  A county with numerous commuters is generally an
integral part of an urban area and is likely contributing to fine
particle concentrations in the area.  

Table 5.  Traffic and Commuting Patterns

County	State Recommended Nonattainment?	2005 VMT

(106 mi)	Number Commuting to any violating county 	Percent

Commuting to any violating county 	Number Commuting within statistical
area 	Percent

Commuting within statistical area 

Cook, IL	Yes	    35,294 	2,113,930 	89	  2,352,120 	99

Lake, IN	No	     4,588 	193,610 	93	    206,350 	99

Will, IL	Yes	     4,605 	185,690 	77	    239,340 	99

Porter, IN	No	     1,677 	25,470 	35	      70,940 	98

DuPage, IL	Yes	     8,802 	161,940 	35	    464,630 	99

Kane, IL	Yes	     3,517 	36,290 	19	    190,780 	99

Grundy, IL	Partial	        623 	6,990 	38	      17,310 	95

Lake, IL	Yes	     6,016 	83,930 	26	    313,250 	99

Kendall, IL	Partial	        678 	4,230 	15	      27,860 	99

McHenry, IL	Yes	     2,104 	31,680 	24	    130,520 	98



The listing of counties on Table 5 reflects a ranking based on the
number of people commuting to other counties.  The counties that are in
the nonattainment area for the 1997 PM2.5 NAAQS are shown in boldface. 
All counties in this table are highly integrated into the Chicago area.

Note:  The 2005 VMT data used for table 5 and 6 of the 9-factor analysis
has been derived using methodology similar to that described in
“Documentation for the final 2002 Mobile National Emissions Inventory,
Version 3, September 2007, prepared for the Emission Inventory Group,
U.S. EPA.  This document may be found at:
ftp://ftp.epa.gov/EmisInventory/2002finalnei/documentation/mobile/2002_m
obile_nei_version_3_report_092807.pdf.  The 2005 VMT data were taken
from documentation which is still draft, but which should be released in
2008.

Factor 5:  Growth rates and patterns  

This factor considers population growth for 2000-2005 and growth in
vehicle miles traveled for 1996-2005 for counties in Chicago area, as
well as patterns of population and VMT growth.  A county with rapid
population or VMT growth is generally an integral part of an urban area
and likely to be contributing to fine particle concentrations in the
area.

Table 6 below shows population, population growth, VMT, and VMT growth
for counties that are included in the Chicago area.  Counties are listed
in descending order based on VMT growth between 1996 and 2005.

Table 6.  Population and VMT Growth and Percent Change.

County	Population (2005)	Population % change (2000-2005)	2005 VMT

(106 mi)	VMT % change

(1996-2005)

Kane, IL	    483,208 	18 	     3,517 	        364 

McHenry, IL	    304,701 	16 	     2,104 	        196 

Kendall, IL	     79,597 	44 	        678 	        166 

Will, IL	    642,625 	26 	     4,605 	        135 

Lake, IL	    704,086 	9 	     6,016 	          82 

DuPage, IL	    931,219 	3 	     8,802 	          43 

Grundy, IL	     43,736 	16 	        623 	          30 

Porter, IN	    157,408 	7 	     1,677 	          10  

Lake, IN	    491,706 	1 	     4,588 	            0

Cook, IL	 5,303,943 	-1	    35,294 	         -14



The growth rates are not expected to yield significant changes in the
distribution of population in the area, so this factor did not
significantly influence the decision-making process.

Factor 6:  Meteorology (weather/transport patterns)

For this factor, EPA considered data from National Weather Service
instruments and other meteorological monitoring sites in the area.  Wind
direction and wind speed data for 2005-2007 were analyzed, with an
emphasis on “high PM2.5 days” for each of two seasons, an
October-April “cold” season and a May-September “warm” season. 
These high days are defined as days where any FRM or FEM air quality
monitors had 24-hour PM2.5 concentrations above 95% on a frequency
distribution curve of PM2.5 24-hour values. 

For each air quality monitoring site, EPA developed a “pollution
rose” to understand the prevailing wind direction and wind speed on
the days with highest fine particle concentrations.  The figure
identifies 24-hour PM2.5 values by color; days exceeding 35 μg/m3 are
denoted with a red or black icon.  A dot indicates the day occurred in
the warm season; a triangle indicates the day occurred in the cool
season.  The center of the figure indicates the location of the air
quality monitoring site, and the location of the icon in relation to the
center indicates the direction from which the wind was blowing on that
day.  An icon that is close to the center indicates a low average wind
speed on that day.  Higher wind speeds are indicated when the icon is
further away from the center.

The pollution rose for the Chicago area is provided in Figure 2.  Winds
on high concentration days predominantly come from the southwest and
southeast, but the overall wind direction is varied.  So, it is
appropriate to include counties in all directions from the violations.

 Figure 2 

Note:  the meteorology factor is also considered in each county’s
Contributing Emissions Score because the method for deriving this metric
included an analysis of trajectories of air masses for high PM2.5 days.

Factor 7:  Geography/topography (mountain ranges or other air basin
boundaries)

The geography/topography analysis evaluates the physical features of the
land that might have an effect on the air shed and, therefore, on the
distribution of PM2.5 over the area.

The Chicago area does not have any geographical or topographical
barriers significantly limiting air-pollution transport within its air
shed.  Therefore, this factor did not play a significant role in the
decision-making process.

Factor 8:  Jurisdictional boundaries

In evaluating the jurisdictional boundary factor, EPA gave special
consideration to areas that were already designated nonattainment in
2005 for violating the 1997 fine particle standards.  Analysis of
chemical composition data in these areas indicates that the same
components that make up most of the PM2.5 mass in the area on an annual
average basis such as sulfate and direct PM2.5 carbon in many eastern
areas also are key contributors to the PM2.5 mass on days exceeding the
24-hour PM2.5 standard.  These data indicate that in many cities, the
same source categories that contribute to violations of the annual
standard also contribute to exceedances of the 24-hour standard.  

EPA has generally concluded that counties that were designated as having
emissions sources contributing to fine particle concentrations exceeding
the 1997 standards (all areas violated the annual standard, two also
violated the previous 24-hour standard) also contribute to fine particle
concentrations on the highest days.  For this reason, EPA believes that
for most existing nonattainment areas, the nonattainment area for the
2006 24-hour standard should be the same.  Use of existing boundaries
also may facilitate air quality planning and the implementation of
control measures to attain the standard.  Areas already designated as
nonattainment represent important boundaries for state air quality
planning.

The Chicago ozone nonattainment area consists of the following counties:
 Cook, Du Page, Kane, Lake, Mc Henry, Will, Aux Sable and Goose Lake
Townships in Grundy County, and Oswego Township in Kendall County in
Illinois and Lake and Porter Counties in Indiana.  The fine particulate
nonattainment area matches these boundaries, which will facilitate
planning.  It is also identical to the fine particulate nonattainment
area designed under the 1997 standards.

The Chicago Area Transportation Study (CATS) Policy Committee is the
Metropolitan Planning Organization (MPO) for the northeastern Illinois
region.  CATS webpage:   HYPERLINK "http://www.catsmpo.com/" 
http://www.catsmpo.com/ .  Northwest Indiana has a separate MPO called
the Northwest Indiana Regional Planning Commission, serving Lake,
Porter, and LaPorte Counties, with a web site at:   HYPERLINK
"http://www.nirpc.org/"  http://www.nirpc.org/ .

 

Factor 9:  Level of control of emission sources 

Under this factor, the existing level of control of emission sources is
taken into consideration.  The emissions data used by EPA in this
technical analysis and provided in Table 1 under Factor 1 represent
emissions levels taking into account any control strategies implemented
in the Chicago area before 2005 on stationary, mobile, and area sources.
 Data are presented for PM2.5 components that are directly emitted,
carbonaceous PM2.5 and crustal PM2.5, and for pollutants which react in
the atmosphere to form fine particles such as SO2, NOx, VOC, and
ammonia.  

In considering county-level emissions, EPA used data from the 2005
National Emissions Inventory, the most updated version of the national
inventory available at the beginning of the designations process in late
2007.  However, EPA recognized that for certain counties, emissions may
have changed since 2005.  For example, certain power plants or large
sources of emissions in or near this area may have installed emission
controls or otherwise significantly reduced emissions since 2005.  Some
States provided updated information on emissions and emission controls
in their comments to EPA.  EPA considered such additional information in
making final designation decisions.  

With regard to nearby power plants, EPA considered information about
whether a specific plant installed federally enforceable emission
controls by December 2008 resulting in significant emissions reductions.
 A control requirement is considered to be federally-enforceable if it
is required by a State regulation adopted in a State implementation
plan, if it is included in a federally-enforceable Title V operating
permit, or if it is required by a consent decree which also requires the
controls to be included in federally enforceable permit upon termination
of the consent decree.  In making final decisions, EPA also considered
whether a facility would continue to emit pollutants which contribute to
PM2.5 exceedances even after emission controls are operational. 

Wisconsin provided information on a power plant in Kenosha County,
Wisconsin.  This is immediately North of the Chicago nonattainment area.
 EPA determined that the Kenosha County facility is well controlled. 
The emission controls are federally enforceable.  Kenosha County is not
considered to contribute to violations in the Chicago area with the
updated emissions information and the information on the other eight
factors.  Therefore, EPA determined that including Kenosha County in the
Chicago nonattainment area is not warranted.  No other information was
provided regarding other power plants or any other large sources in the
Chicago area.

Note: EPA has provided a thorough response to each of the specific
comments raised by the State in the Response to Comments document. 
Additional information regarding responses to specific State comments
can be found in EPA’s Response to Comments document at   HYPERLINK
"http://www.epa.gov/pmdesignations/2006standards/tech.htm" 
http://www.epa.gov/pmdesignations/2006standards/tech.htm .

EPA Technical Analysis for Davenport-Rock Island-Moline, IA- IL 

The Davenport-Moline-Rock Island area is currently designated attainment
for PM2.5.  A monitor in Davenport (Scott County) is showing violations
of the standard.  Illinois recommended including no part of Illinois in
the nonattainment area.  EPA reviewed relevant information for the four
counties in the metropolitan statistical area and for surrounding
counties.	 

EPA believes that Rock Island County has moderate emissions that
commonly are blown toward the violating monitor in Scott County.  We
also believe that sufficient commuting occurs between Rock Island County
and Scott County such that Rock Island County must be considered an
integral part of the Davenport (Quad Cities) area.  

EPA recognizes that emissions in close proximity to the monitor may make
an important contribution to the violations.  Indeed, EPA recognizes the
possibility that reduction of the emissions close to the monitor may
suffice to address the violation.  Nevertheless, our obligation under
Clean Air Act section 107 in defining a nonattainment area is to
identify the area that is violating the standard and the nearby area
that is contributing to the violation.  The nearby area that contributes
to the violation is then included in the planning area evaluated for
measures for attaining the standard.  Even if the state already suspects
that its control strategy will focus on sources in the immediate
vicinity of the violating monitor, EPA must apply a nonattainment
designation to the entire nearby area that contributes to the violation,
such that the SIP planning will address the entire nearby contributing
area.  

Furthermore, the available evidence suggests that local emissions in the
immediate vicinity of the monitor contribute only a fraction of the
concentrations in Davenport.  A much larger fraction of the
concentrations in Davenport arise from emissions farther from the
monitor.  EPA believes that an important component of these
concentrations arises from a contribution from emissions throughout the
Quad Cities area.  While the impact of Rock Island County appears to be
less than that of Scott County, Iowa, the impact nevertheless appears
sufficiently substantial to include Rock Island County in the
nonattainment area.

Illinois and Iowa provided extensive information on the impacts of
various sources and areas on the violating monitor in Scott County,
including both modeling using AERMOD assessing impacts of point sources
in Rock Island County on Scott County concentrations and using CAMx
assessing the impact of Scott County zeroing out the emissions of Rock
Island County.  In EPA’s view, these modeling results confirm that
while Rock Island County emissions represent only a fraction of the
origins of the violation in Scott County, the impact is nevertheless
sufficient to warrant a conclusion that at least portions of Rock Island
County contribute to the nearby Davenport violation.

Iowa provided further information on emissions for portions of Scott
County.  EPA also examined information on the distribution of emissions
and population within Rock Island County.  These data suggest that
emissions and population are highly concentrated within the urban
portions of these counties, such that designating a portion of these
counties will suffice to include the predominant fraction of both
PM2.5-related emissions and population.  EPA is including the following
townships within Rock Island County in the Davenport-Rock Island-Moline
nonattainment area:  Black Hawk, Coal Valley, Hampton, Moline, Rock
Island, South Moline, and South Rock Island Townships.  These townships
include about 89 percent of the population, about 97 percent of the
emissions of SO2 in the county, and about 87 percent of the NOx
emissions in the county.  When considered in combination with the
partial county nonattainment area in Scott County, Iowa, the area being
designated nonattainment includes about 89 percent of the population,
about 98 percent of the SO2 emissions, and about 91 percent of the NOx
emissions present in Scott and Rock Island Counties.  Consequently, EPA
believes that this group of townships, in combination with the
designated area in Iowa, represents the area nearby to the violation
that is violating or contributing to violations of the 24-hour PM2.5
standard.

EPA also examined information for Henry and Mercer Counties as well as
for nearby counties outside the metropolitan area.  EPA found that these
other counties are more distant from the violating monitor in Davenport,
have relatively low emissions, and no other factor warranted inclusion
of the counties in the nonattainment area.

Figure 1 is a map of the counties in the nonattainment area and other
relevant information such as the locations and design values of air
quality monitors, and the metropolitan area boundary. 

 

Figure 1

In its August 6, 2008 letter, Illinois recommended that EPA designate
Rock Island County in the Davenport area as “attainment” for the
2006 24-hour PM2.5 standard based on air quality data from 2005-2007. 
These data are from Federal Reference Method (FRM) monitors located in
the state.

 

On August 18, 2008, EPA notified Illinois and Iowa of its intended
designations.  In this letter, EPA also requested that if the State
wished to provide comments on EPA’s intended designation, it should do
so by October 20, 2008.  EPA stated that it would consider any
additional information (e.g., on power plants or partial county areas)
provided by the state in making final decisions on the designations.  

Based on EPA's technical analysis of currently available information, as
described below, EPA has designated a partial county in Illinois and a
partial county in Iowa as nonattainment for the 24-hour PM2.5
air-quality standard as the Davenport nonattainment area.

The following is a review of data for relevant factors for the Davenport
area.

Factor 1:  Emissions data

For this factor, EPA evaluated county level emission data for the
following PM2.5 components and precursor pollutants:  “PM2.5 emissions
total,” “PM2.5 emissions carbon,” “PM2.5 emissions other,”
“SO2,” “NOx,” “VOCs,” and “NH3.”  “PM2.5 emissions
total” represents direct emissions of PM2.5 and includes: “PM2.5
emissions carbon,” “PM2.5 emissions other”, primary sulfate (SO4),
and primary nitrate.  (Although primary sulfate and primary nitrate,
which are emitted directly from stacks rather than forming in
atmospheric reactions with SO2 and NOx, are part of “PM2.5 emissions
total,” they are not shown in Table 1 as separate items).  “PM2.5
emissions carbon” represents the sum of organic carbon (OC) and
elemental carbon (EC) emissions, and “PM2.5 emissions other”
represents other inorganic particles (crustal).  Emissions of SO2 and
NOx, which are precursors of the secondary PM2.5 components sulfate and
nitrate, are also considered.  VOCs (volatile organic compounds) and NH3
(ammonia) are also potential PM2.5 precursors and are included for
consideration. 

Emissions data were derived from the 2005 National Emissions Inventory
(NEI), version 1.  See
http://www.epa.gov/ttn/naaqs/pm/pm25_2006_techinfo.html.

EPA also considered the Contributing Emissions Score (CES) for each
county.  The CES is a metric that takes into consideration emissions
data, meteorological data, and air quality monitoring information to
provide a relative ranking of counties in and near an area.  Note that
this metric is not the exclusive manner for considering data for these
factors.  A more detailed description can be found at
http://www.epa.gov/ttn/naaqs/pm/pm25_2006_techinfo.html#C.

Table 1 shows emissions of PM2.5 and precursor pollutants components
(given in tons per year) and the CES for violating and potentially
contributing counties in the Davenport area.  Counties are listed in
descending order by CES.

Table 1.  PM2.5 24-hour Component Emissions, and CESs. 

County	State Recommended Nonattainment?	CES	PM2.5

emissions 

total	PM2.5

emissions 

carbon	PM2.5

emissions 

other	SO2	NOx	VOCs

	NH3

Scott, IA	Yes, Partial	100	2,034	395	1,639	9,173	11,317	9,323	1,986

Muscatine, IA	Yes, Other	80	1,702	283	1,419	27,020	10,717	4,910	1,083

Clinton, IA	No	52	2,711	354	2,357	11,506	13,217	11,503	4,870

Rock Island, IL	No	27	932	269	663	2,169	6,140	7,359	664

Henry, IL	No	7	1,273	252	1,021	268	6,648	3,431	2,805

Mercer, IL	No	4	793	149	644	133	1,120	1,469	1,026



Table 2 provides the data for CES weighting factors.  The trajectory
factors are used in CES calculations to account for seasonal
meteorology.  For the top 10% of days in both the cold and warm seasons,
wind trajectories were run for a 48 hour period preceding the high
monitor reading.  The amount of time the air mass was over a county
within the mixing height was calculated.  The values were scaled so that
the maximum value is 100.  Thus, the county that is most likely to be
upwind of a monitor on a high concentration day in a season is given a
score of 100.  The scores for the other counties will reflect the
relative likelihood of being upwind.  As the concentration of a
pollutant will decrease as it goes further downwind, a distance
weighting factor is also used in calculating the CES.  The distance
factor listed on Table 2 provides the distance from the center of a
county to the center of the violating county.  If a county is violating,
the distance used is the average distance from the center to the county
line.

  Table 2.  CES Factor Data.

County	CES	Trajectory Factor- Cold	Trajectory Factor- Warm	Distance (mi)

Scott, IA	100	100	78	11.9

Muscatine, IA	80	75	65	25.7

Clinton, IA	52	75	50	19.1

Rock Island, IL	27	98	87	16.9

Henry, IL	7	68	59	29.9

Mercer, IL	4	91	100	29.4



In Illinois, Rock Island County has a substantial fraction of the
area’s emissions.  Henry and Mercer Counties have limited emissions.

Iowa recommended that only a portion of Scott County be designated
nonattainment.  EPA reviewed the pertinent information and concluded
that the nonattainment area recommended by Iowa excluded much of the
emissions that contribute to the violation.  A more extensive discussion
of this review is provided elsewhere in this technical support document.
 

EPA conducted an extensive review of available information to assess
information on emissions from subcounty portions of Scott and Rock
Island Counties.  This review relied on information from the 2002 NEI as
available from EPA’s Technology Transfer Network web site, given the
ease of access to information with which to estimate subcounty
emissions.  This review focused on assessing emissions of the urban
portions of Scott and Rock Island Counties, although use of recognized
township jurisdictional boundaries leads to inclusion of some areas that
are relatively rural.  For purposes here, the urban portion of Scott
County is being defined to include the entirety of Buffalo, Davenport,
Pleasant Valley, and Sheridan Townships, and the portions of Blue Grass,
Hickory Grove, and Lincoln Townships that are within the City of
Davenport.  For purposes here, the urban portion of Rock Island County
is being defined to include Black Hawk, Coal Valley, Hampton, Moline,
Rock Island, South Moline, and South Rock Island Townships.

Detailed discussion of inventory information for Scott County is
included elsewhere in this technical support document.  For Rock Island
County, the urban portion includes virtually all emissions of sulfur
dioxide.  For point sources, according to 2002 NEI information, the
urban portion includes 1,792 or 99 percent of the 1,812 tons per year
emitted in Rock Island County.  Using population as an approximate
surrogate for the distribution of mobile and area source sulfur dioxide
emissions in the county, 359 of the 403 tons per year are estimated to
be emitted in the urban portion.  In total across Rock Island County,
the urban portion is estimated to have 2,151 or 87 percent of the 2215
tons per year of sulfur dioxide emissions in Rock Island County.  For
NOx, again using population as an approximate surrogate for the
distribution of mobile and area source NOx emissions, 89 percent of the
6,292 tons per year of this category of Rock Island County NOx
emissions, or approximately 5,600 tons per year, are emitted in the
urban portion of the county.  Of the 730 tons per year of point source
NOx emissions estimated in the 2002 inventory, 544 are emitted by
sources in the urban portion of the county.  In total, 87 percent of the
NOx emissions are emitted from the urban portion of the county.  In
Scott County, using similar assumptions regarding spatial distribution,
approximately 11,917 of the 12,820 tons per year are estimated to be
emitted in the urban portion of the county.  In total, EPA estimates
that 91 percent of the total NOx emissions from the two counties is
emitted in the urban portions of these counties.

For fine particulate matter, EPA estimates that 96 of the 170 tons per
year of point source direct emissions of fine particulate matter are
emitted in the urban portion of the area.  Again using population as an
approximate surrogate for the distribution of mobile and area source
PM2.5 emissions, 89 percent of the 462 tons per year emitted by mobile
sources and by minor point sources in Rock Island County (411 tons per
year) is emitted within the urban portion of the county.  In total, 80
percent of these emissions are emitted in the urban portion of the area.
 Similarly, for Scott County, EPA estimates that 1632 or 95 percent of
the 1714 tons per year of major point, minor point, and mobile source
emissions is emitted in the urban portion of the county.  In total
across the two counties, EPA estimates that 91 percent of these
emissions are emitted from the urban portion of these counties.

The 2002 inventory also indicates a significant quantity of PM2.5
emissions emitted from agricultural tilling and fugitive dust from
roadways.  This component of particulate matter (labeled “crustal”
or miscellaneous inorganic particulate matter) is found to represent a
low fraction of observed total particulate matter, either on a total
composition basis or on an estimated “urban excess” basis.  EPA also
does not have reliable information to assess what fraction of fugitive
dust from roadways is emitted in the urban versus the rural portions of
these counties.  Although some of the road dust emissions and a small
fraction of the agricultural tilling emissions occur within the
identified townships, EPA conservatively assumed that all of these
emissions are outside the defined “urban” area.  In Rock Island
County, these emissions are estimated to be 505 tons per year, such that
the “urban” portion of Rock Island County is estimated to emit a
total of 507 tons per year out of a county total of 1137 tons per year,
or 45 percent.  Using similar estimates from Scott County, the total
emissions in the “urban” portions of the two counties is 2139 tons
per year, or 63 percent of the 3395 tons per year emitted across the
full two counties.

Factor 2:  Air quality data 

This factor considers the 24-hour PM2.5 design values (in µg/m3) for
air quality monitors in counties in the Davenport area based on data for
the 2005-2007 period.  A monitor’s design value indicates whether that
monitor attains a specified air quality standard.  The 24-hour PM2.5
standards are met when the 3-year average of a monitor’s 98th
percentile values are 35 µg/m3 or less.  A design value is only valid
if minimum data completeness criteria are met. 

The 24-hour PM2.5 design values for counties in the Davenport area are
shown in Table 3.

	Table 3.  Air Quality Data

County	State 

Recommended

Nonattainment?	Design Values

2004-2006	Design Values

2005-2007

Scott, IA	Yes, Partial	32	37

Rock Island, IL	No	30	31

Henry, IL	No	*0	*

Mercer, IL	No	8	*

Muscatine, IA	Yes, Other	34	36

Clinton, IA	No 	34	32



Scott County, Iowa exceeded the 24-hour PM2.5 standard in 2005-2007. 
There were no violations in the Illinois portion of the Davenport
nonattainment area.  However, the absence of a violating monitor alone
is not a sufficient reason to eliminate counties as candidates for
nonattainment status.  Each county has been evaluated based on the
weight of evidence of the nine factors and other relevant information.

For purposes of its review, EPA used data available from the Chemical
Speciation Network and the Interagency Monitoring of Protected Visual
Environments (IMPROVE) network to estimate the composition of fine
particle mass on days with the highest fine particle concentrations. 
Analysis of these data indicates that the days with the highest fine
particle concentrations in the Davenport area occur about 58% in the
warm season and 42% in the cool season.  In the warm season, the average
chemical composition of the highest days is 77% sulfate, no nitrate, 20%
carbon, and 2% crustal.  In the cool season, the average chemical
composition of the highest days is 26% sulfate, 55% nitrate, 17% carbon,
and 2% crustal.  These data indicate that sources of SO2, NOx, and
direct PM2.5 emissions contribute to violations in the area.

Note:  Eligible monitors for providing design value data generally
include State and Local Air Monitoring Stations (SLAMS) at
population-oriented locations with an FRM monitor.  All data from
Special Purpose Monitors (SPM) using an FRM is eligible for comparison
to the relevant NAAQS, subject to the requirements given in the October
17, 2006 Revision to Ambient Air Monitoring Regulations (71 FR 61236). 
All monitors used to provide data must meet the monitor siting and
eligibility requirements given in 71 FR 61236 to 61328 in order to be
acceptable for comparison to the 24-hr PM2.5 NAAQS for designation
purposes.

Factor 3: Population density and degree of urbanization (including
commercial development)

Table 4 shows the 2005 population for each county in the area being
evaluated, as well as the population density for each county in that
area.  Population data gives an indication of whether it is likely that
population-based emissions might contribute to violations of the 24-hour
PM2.5 standards. 

Table 4.  Population

County	State Recommended Nonattainment?	2005 Population	2005 Population
Density (pop/mi2)

Scott, IA	Yes, Partial	    161,170 	345

Rock Island, IL	No	    147,454 	327

Henry, IL	No	     50,508 	61

Mercer, IL	No	     16,840 	30

Muscatine, IA	Yes, Other	     42,567 	95

Clinton, IA	No	     49,744 	70



The populations of Rock Island County, Illinois and Scott County, Iowa
stand out above the other area counties.

EPA further examined the population residing in the urban portions of
Scott and Rock Island Counties.  The definition that EPA used of the
urban portions of these counties is described under Factor 1 above.  EPA
found that the urban portion of Scott County includes 89 percent of the
county’s population (approximately 144,000 people), and the urban
portion of Rock Island County also includes 89 percent of that
county’s population (approximately 131,000 people).  Thus, the
combined urban portions of these counties (as described above) include
89 percent of the population of the two counties.

Factor 4: Traffic and commuting patterns 

This factor considers the number of commuters in each county who drive
within or into the Davenport area, the percent of total commuters in
each county who commute within or into the area, as well as the total
Vehicle Miles Traveled (VMT) for each county in millions of miles (see
Table 5).  A county with numerous commuters is generally an integral
part of an urban area and is likely contributing to fine particle
concentrations in the area.  

Table 5.  Traffic and Commuting Patterns

County	State Recommended Nonattainment?	2005 VMT

(106 mi)	Number Commuting to any violating counties

	Percent

Commuting to any violating counties 	Number Commuting into statistical
area 	Percent

Commuting into statistical area 

Scott, IA	Yes, Partial	    1,614 	61,500 	79 	      74,020 	          95


Rock Island, IL	No	    1,313 	14,240 	20 	      67,530 	          97 

Henry, IL	No	       695 	1,870 	8 	      22,340 	          91 

Mercer, IL	No	       135 	1,200 	15 	        6,570 	          85 

Clinton, IA	No	       423 	2,610 	11 	        3,600 	          15 

Muscatine, IA	Yes, Other	       372 	17,330 	85 	        1,060 	        
   5 



The listing of counties on Table 4 reflects a ranking based on the
number of people commuting into or within the Davenport area.  Scott
County, Iowa and Rock Island County, Illinois have the most commuters
within the Davenport area.

Note:  The 2005 VMT data used for table 5 and 6 of the 9-factor analysis
has been derived using methodology similar to that described in
“Documentation for the final 2002 Mobile National Emissions Inventory,
Version 3, September 2007, prepared for the Emission Inventory Group,
U.S. EPA.  This document may be found at:
ftp://ftp.epa.gov/EmisInventory/2002finalnei/documentation/mobile/2002_m
obile_nei_version_3_report_092807.pdf.  The 2005 VMT data were taken
from documentation which is still draft, but which should be released in
2008.

Factor 5:  Growth rates and patterns  

This factor considers population growth for 2000-2005 and growth in
vehicle miles traveled for 1996-2005 for counties in Davenport area, as
well as patterns of population and VMT growth.  A county with rapid
population or VMT growth is generally an integral part of an urban area
and likely to be contributing to fine particle concentrations in the
area.

Table 6 below shows population, population growth, VMT, and VMT growth
for counties that are included in the Davenport area.  Counties are
listed in descending order based on VMT growth between 1996 and 2005.

Table 6.  Population and VMT Growth and Percent Change.

Location	Population (2005)	Population % change (2000-2005)	2005 VMT

(106 mi)	VMT

% change

(1996-2005)

Muscatine, IA	     42,567 	2 	        372 	          43

Clinton, IA	     49,744 	-1	        423 	          39 

Scott, IA	    161,170 	2 	     1,614 	          25 

Henry, IL	     50,508 	-1	        695 	            7 

Rock Island, IL	    147,454 	-1	     1,313 	            3 

Mercer, IL	     16,840 	-1	        135 	         -12



The growth rates are not expected to yield significant changes in the
distribution of population in the area, so this factor did not
significantly influence EPA’s decision.

Factor 6:  Meteorology (weather/transport patterns)

For this factor, EPA considered data from National Weather Service
instruments and other meteorological monitoring sites in the area.  Wind
direction and wind speed data for 2005-2007 were analyzed, with an
emphasis on “high PM2.5 days” for each of two seasons, an
October-April “cold” season and a May-September “warm” season. 
These high days are defined as days where any FRM or FEM air quality
monitors had 24-hour PM2.5 concentrations above 95% on a frequency
distribution curve of PM2.5 24-hour values. 

For each air quality monitoring site, EPA developed a “pollution
rose” to understand the prevailing surface-level wind direction and
wind speed on the days with highest fine particle concentrations.  The
pollution rose for the Davenport area is Figure 2, and is constructed
from wind indicators from a site located in Rock Island County.  The
figure identifies 24-hour PM2.5 values by color; days exceeding 35
μg/m3 are denoted with a red or black icon.  A dot indicates the day
occurred in the warm season; a triangle indicates the day occurred in
the cool season.  The center of the figure indicates the location of the
air quality monitoring site, and the location of the icon in relation to
the center indicates the direction from which the wind was blowing on
that day.  An icon that is close to the center indicates a low average
wind speed on that day.  Higher wind speeds are indicated when the icon
is further away from the center.

The Davenport area pollution rose indicates that winds on high
concentration days come from a variety of directions, and occur under
both high wind and low wind conditions.  So, it is appropriate to
consider counties in all directions from the violations for this factor.
 The winds on high concentration days in the warm season are more likely
to come from the south to southwest direction.  In contrast, the winds
on high concentration days in the cold season come from multiple
directions, and occur mainly with winds averaging less than 8 mph.  

 

Figure 2

Note:  The meteorology factor is also considered in each county’s
Contributing Emissions Score because the method for deriving this metric
included an analysis of trajectories of air masses for high PM2.5 days. 
Also, Iowa provided a separate wind rose and a pollution rose
constructed from a site in Scott County, Iowa in the information
accompanying their recommendations.  This additional information is
discussed in the Iowa TSD. 

Factor 7:  Geography/topography (mountain ranges or other air basin
boundaries)

The geography/topography analysis evaluates the physical features of the
land that might have an effect on the air shed and, therefore, on the
distribution of PM2.5 over the area.

The Davenport area does not have any geographical or topographical
barriers significantly limiting air-pollution transport within its air
shed.  Therefore, this factor did not significantly influence EPA’s
decision.

Factor 8:  Jurisdictional boundaries

In evaluating the jurisdictional boundary factor, EPA gave special
consideration to areas that were already designated nonattainment in
2005 for violating the 1997 fine particle standards.  However, this area
was designated attainment for the 1997 standards, so nonattainment area
boundaries for the 1997 standards were not a factor in determining this
area’s boundaries.  

Transportation planning for the Quad Cities area is accomplished through
the Bi-State Regional Commission, which is the Metropolitan Planning
Organization (MPO).  The MPO serves Henry, Mercer, and Rock Island
Counties in Illinois and Scott and Muscatine Counties in Iowa.  Its web
site is   HYPERLINK "http://www.bistateonline.org" 
www.bistateonline.org .  The Bi-State planning area itself was not a key
factor in determining the Davenport area nonattainment boundary; other
factors pointed to an area smaller than the entire 5-county area. 

Factor 9:  Level of control of emission sources 

Under this factor, the existing level of control of emission sources is
taken into consideration.  The emissions data used by EPA in this
technical analysis and provided in Table 1 under Factor 1 represent
emissions levels taking into account any control strategies implemented
in the Davenport area before 2005 on stationary, mobile, and area
sources.  Data are presented for PM2.5 components that are directly
emitted, carbonaceous PM2.5 and crustal PM2.5, and for pollutants which
react in the atmosphere to form fine particles such as SO2, NOx, VOC,
and ammonia.  

In considering county-level emissions, EPA used data from the 2005
National Emissions Inventory, the most updated version of the national
inventory available at the beginning of the designations process in late
2007.  However, EPA recognized that for certain counties, emissions may
have changed since 2005.  For example, certain power plants or large
sources of emissions in or near this area may have installed emission
controls or otherwise significantly reduced emissions since 2005.  Some
States provided updated information on emissions and emission controls
in their comments to EPA.  EPA considered such additional information in
making final designation decisions.  

With regard to nearby power plants, EPA considered information about
whether a specific plant installed federally enforceable emission
controls by December 2008 resulting in significant emissions reductions.
 A control requirement is considered to be federally-enforceable if it
is required by a State regulation adopted in a State implementation
plan, if it is included in a federally-enforceable Title V operating
permit, or if it is required by a consent decree which also requires the
controls to be included in federally enforceable permit upon termination
of the consent decree.  In making final decisions, EPA also considered
whether a facility would continue to emit pollutants which contribute to
PM2.5 exceedances even after emission controls are operational. 

Illinois did not provide information on control of sources in Rock
Island County, and EPA assumes that the emission estimates in the 2005
inventory reasonably represent current emissions.

EPA Technical Analysis for Paducah-Mayfield, KY-IL 

The only monitor in the Paducah-Mayfield area is in McCracken County,
Kentucky.  Kentucky requested concurrence on several claims that
elevated concentrations were attributable to exceptional events, in
particular due to wildfires.  EPA reviewed this request, denied some of
these claims, and concluded that the Paducah area is violating the
24-hour PM2.5 standard.

The Paducah-Mayfield combined statistical area includes one county in
Illinois:  Massac County.  This county has a relatively high fraction of
the emissions in the area, and the winds commonly blow from Massac
County into McCracken County on high concentration days.  A substantial
fraction of the Massac County emissions are attributable to the Joppa
Steam Plant. 

Illinois provided information that Ameren, the owner of the Joppa Steam
Plant, has committed to install and operate control equipment, including
separated overfire air in 2010 and scrubbers and baghouses in 2013 and
2014.  EPA applauds these commitments and notes that these controls will
ease the effort of planning for attainment.  Nevertheless, EPA is
promulgating designations based on current contributions to current air
quality, and is not adjusting nonattainment area boundaries to reflect
control that is not planned to be in place until two years and more into
the future.  

Illinois also provided additional information on the location of the
Joppa Steam Plant in relation to Paducah, in conjunction with wind
information to indicate that winds rarely blow from the Joppa Steam
Plant toward the violating monitor in Paducah on days when the monitor
is exceeding the 24-hour standard.  Further discussion of this
information is provided in the response to comments document.  EPA found
that current emissions at this facility are sufficiently high and winds
blow sufficiently frequently from the plant toward Paducah to conclude
that the plant’s emissions contribute to the violation.  

The Joppa Steam Plant emits virtually all of the SO2 emitted in Massac
County and a significant fraction of the NOx and directly emitted
particulate matter emitted in the county.  The population in Massac
County and the number of commuters commuting from Massac County to
Paducah are relatively low.  Therefore, EPA believes that the
contribution of Massac County to violations in Paducah can be adequately
captured by including just the portion of Massac County that includes
the Joppa Steam Plant.  This plant is located in Hillerman Precinct of
Massac County.  Therefore, EPA is designating a Paducah nonattainment
area that in Illinois only includes Hillerman Precinct.

EPA also examined information for other Illinois counties around the
Paducah-Mayfield area.  These other counties have relatively low
emissions, and no other factor warrants their inclusion in the
Paducah-Mayfield nonattainment area.

Figure 1 is a map of the counties in the nonattainment area and other
relevant information such as the locations and design values of air
quality monitors, and the metropolitan area boundary. 

 

In its June 2, 2008 letter, Illinois recommended that the Illinois
counties in the Paducah area be designated as “attainment” for the
2006 24-hour PM2.5 standard based on air quality data from 2005-2007. 
These data are from Federal Reference Method (FRM) monitors located in
the state.

 

In August 2008, EPA notified Illinois and Kentucky of its intended
designations.  In this letter, EPA also requested that if the State
wished to provide comments on EPA’s intended designation, it should do
so by October 20, 2008.  EPA stated that it would consider any
additional information (e.g., on power plants or partial county areas)
provided by the state in making final decisions on the designations.  

Based on EPA's technical analysis described below, EPA has designated a
Paducah nonattainment area that in Illinois includes Hillerman Precinct
in Massac County, based upon currently available information.  

The following is a review of data for relevant factors for the Paducah
area.

Factor 1:  Emissions data

For this factor, EPA evaluated county level emission data for the
following PM2.5 components and precursor pollutants:  “PM2.5 emissions
total,” “PM2.5 emissions carbon,” “PM2.5 emissions other,”
“SO2,” “NOx,” “VOCs,” and “NH3.”  “PM2.5 emissions
total” represents direct emissions of PM2.5 and includes: “PM2.5
emissions carbon,” “PM2.5 emissions other”, primary sulfate (SO4),
and primary nitrate.  (Although primary sulfate and primary nitrate,
which are emitted directly from stacks rather than forming in
atmospheric reactions with SO2 and NOx, are part of “PM2.5 emissions
total,” they are not shown in Table 1 as separate items).  “PM2.5
emissions carbon” represents the sum of organic carbon (OC) and
elemental carbon (EC) emissions, and “PM2.5 emissions other”
represents other inorganic particles (crustal).  Emissions of SO2 and
NOx, which are precursors of the secondary PM2.5 components sulfate and
nitrate, are also considered.  VOCs (volatile organic compounds) and NH3
(ammonia) are also potential PM2.5 precursors and are included for
consideration. 

Emissions data were derived from the 2005 National Emissions Inventory
(NEI), version 1.  See
http://www.epa.gov/ttn/naaqs/pm/pm25_2006_techinfo.html.

EPA also considered the Contributing Emissions Score (CES) for each
county.  The CES is a metric that takes into consideration emissions
data, meteorological data, and air quality monitoring information to
provide a relative ranking of counties in and near an area.  Note that
this metric is not the exclusive manner for considering data for these
factors.  A more detailed description can be found at
http://www.epa.gov/ttn/naaqs/pm/pm25_2006_techinfo.html#C.

Table 1 shows emissions of PM2.5 components (given in tons per year) and
the CESs for potentially contributing counties in the Paducah area. 
Counties are listed in descending order by CES.

Table 1.  PM2.5 24-hour Component Emissions, and CESs. 

County	State Recommended Nonattainment?	CES	PM2.5

emissions 

total	PM2.5

emissions 

carbon	PM2.5

emissions 

other	SO2

	NOx

	VOCs

	NH3



McCracken, KY	No	100	1,339	293	1,046	38,956	24,803	6,661	366

Massac, IL	No	66	1,958	159	1,799	26,884	12,369	2,612	417

Graves, KY	No	6	797	278	520	413	1,735	1,867	2,538

Ballard, KY	No	5	596	140	456	927	2,785	1,661	855

Livingston, KY	No	3	318	121	197	337	2,155	1,200	239



McCracken and Massac Counties have substantially greater emissions than
the other nearby counties.

Table 2 provides the data for CES weighting factors.  The trajectory
factors are used in CES calculations to account for seasonal
meteorology.  For the top 10% of days in both the cold and warm seasons,
wind trajectories were run for a 48 hour period preceding the high
monitor reading.  The amount of time the air mass was over a county
within the mixing height was calculated.  The values were scaled so that
the maximum value is 100.  The county that is most likely to be upwind
of a monitor on a high concentration day in a season is given a score of
100.  The scores for the other counties will reflect the relative
likelihood of being upwind.  As the concentration of a pollutant will
decrease as it goes further downwind, a distance weighting factor is
also used in calculating the CES.  The distance factor listed on Table 2
provides the distance from the center of a county to the center of the
violating county.  If a county is violating, the distance used is the
average distance from the center to the county line.

  Table 2.  CES Factor Data.

County	CES	Trajectory Factor- Cold	Trajectory Factor- Warm	Distance (mi)

McCracken	100	95	98	8.9

Massac	66	85	94	8.2

Graves	6	100	80	25.3

Ballard	5	76	77	16.3

Livingston	3	82	100	23.3



Factor 2:  Air quality data 

This factor considers the 24-hour PM2.5 design values (in µg/m3) for
air quality monitors in counties in the Paducah area based on data for
the 2005-2007 period.  A monitor’s design value indicates whether that
monitor attains a specified air quality standard.  The 24-hour PM2.5
standards are met when the 3-year average of a monitor’s 98th
percentile values are 35 µg/m3 or less.  A design value is only valid
if minimum data completeness criteria are met. 

The 24-hour PM2.5 design values for counties in the Paducah area are
shown in Table 3.

	Table 3.  Air Quality Data

County	State 

Recommended

 Nonattainment?	Design Values

2004-06

(µg/m3)

	Design Values

2005-07

(µg/m3)



McCracken, KY	No	33	36

Massac, IL	No	0	0

Graves, KY	No	0	0

Ballard, KY	No	0	0

Livingston, KY	No	0	0



Under this factor, we also consider fine particle composition monitoring
data.  Air quality monitoring data on the composition of fine particle
mass are available from the EPA Chemical Speciation Network and the
IMPROVE monitoring network.  Analysis of these data indicates that the
days with the highest fine particle concentrations in the Paducah area
occuring about 90% in the warm season and about 10% in the cool season. 
In the warm season, the average chemical composition of the highest days
is 79% sulfate, 19% carbon, 2% crustal, and 0% nitrate.  In the cool
season, the average chemical composition of the highest days is 52%
sulfate, 25% carbon, 21% nitrate, and 2% crustal.  These data indicate
that sources of SO2, direct PM2.5, and NOx emissions contribute to
violations in the area.

McCracken County, Kentucky shows a violation of the 24-hour PM2.5
standard for 2005-2007.  There is no monitoring data in the Illinois
portion of the Paducah area.  However, the absence of a violating
monitor or monitoring data is not a sufficient reason to eliminate
counties as candidates for nonattainment status.  Each county in the
area has been evaluated based on the weight of evidence of the nine
factors and other relevant information.

Note:  Eligible monitors for providing design value data generally
include State and Local Air Monitoring Stations (SLAMS) at
population-oriented locations with an FRM monitor.  All data from
Special Purpose Monitors (SPM) using an FRM is eligible for comparison
to the relevant NAAQS, subject to the requirements given in the October
17, 2006 Revision to Ambient Air Monitoring Regulations (71 FR 61236). 
All monitors used to provide data must meet the monitor siting and
eligibility requirements given in 71 FR 61236 to 61328 in order to be
acceptable for comparison to the 24-hr PM2.5 NAAQS for designation
purposes.

Factor 3: Population density and degree of urbanization (including
commercial development)

Table 4 shows the 2005 population for each county in the area being
evaluated, as well as the population density for each county in that
area.  Population data gives an indication of whether it is likely that
population-based emissions might contribute to violations of the 24-hour
PM2.5 standards. 

Table 4.  Population

County	State Recommended Nonattainment?	2005 Population	2005 Population
Density (pop/sq mi)

McCracken, KY	No	     64,690 	241

Massac, IL	No	     15,225 	63

Graves, KY	No	     37,650 	68

Ballard, KY	No	       8,262 	30

Livingston, KY	No	       9,783 	29



Massac County, Illinois has a low population of just over 15,000. 
McCracken County, Kentucky, is the central county in the area and has
population more than four times larger.

Factor 4: Traffic and commuting patterns 

This factor considers the number of commuters in each county who drive
to another county within the Paducah area the percent of total commuters
in each county who commute within the area, as well as the total Vehicle
Miles Traveled (VMT) for each county in millions of miles (see Table 5).
 A county with numerous commuters is generally an integral part of an
urban area and is likely contributing to fine particle concentrations in
the area.  

Table 5.  Traffic and Commuting Patterns

County	State Recommended Nonattainment?	2005 VMT

(106 mi)	Number Commuting to any violating counties	Percent

Commuting to any violating counties 	Number Commuting within statistical
area 	Percent

Commuting within statistical area 

McCracken, KY	No	       832 	24,200 	84 	      26,830 	          93 

Graves, KY	No	       435 	2,350 	15 	      12,880 	          83 

Massac, IL	No	       225 	1,950 	30 	        5,860 	          90 

Livingston, KY	No	       174 	1,770 	41 	        3,580 	          82 

Ballard, KY	No	       102 	1,290 	35 	        3,380 	          92 



McCracken County has the highest VMT and highest number of commuters of
any county in the area.  A modest percentage of workers commute from
Massac County and the other area counties to McCracken County, but
numbers of total commuters to McCracken County are fairly low.

Note:  The 2005 VMT data used for table 5 and 6 of the 9-factor analysis
has been derived using methodology similar to that described in
“Documentation for the final 2002 Mobile National Emissions Inventory,
Version 3, September 2007, prepared for the Emission Inventory Group,
U.S. EPA.  This document may be found at:
ftp://ftp.epa.gov/EmisInventory/2002finalnei/documentation/mobile/2002_m
obile_nei_version_3_report_092807.pdf.  The 2005 VMT data were taken
from documentation which is still draft, but which should be released in
2008.

Factor 5:  Growth rates and patterns  

This factor considers population growth for 2000-2005 and growth in
vehicle miles traveled for 1996-2005 for counties in Paducah area, as
well as patterns of population and VMT growth.  A county with rapid
population or VMT growth is generally an integral part of an urban area
and likely to be contributing to fine particle concentrations in the
area.

Table 6 below shows population, population growth, VMT, and VMT growth
for counties in the Paducah area.  Counties are listed in descending
order based on VMT growth between 1996 and 2005.

Table 6.  Population and VMT Growth and Percent Change.

County	Population (2005)	Population % change (2000-2005)	2005 VMT

(106 mi)	VMT % 

change

(1996-2005)

McCracken, KY	     64,690 	-1	        832 	          26 

Massac, IL	     15,225 	1 	        225 	          25 

Graves, KY	     37,650 	2 	        435 	          21 

Ballard, KY	       8,262 	-1	        102 	          12 

Livingston, KY	       9,783 	0 	        174 	          56 



All of the counties in the Paducah-Mayfield CSA showed negligible
population change between 2000 and 2005.  VMT generally increased in all
counties, with McCracken, KY, and Massac, IL having fairly sizeable
increases in VMT from 1996 to 2005, at 26 and 25 percent, respectively.

Overall, population growth rates are not expected to yield significant
changes in the distribution of population in the area, so this factor
did not significantly influence the decision-making process.

Factor 6:  Meteorology (weather/transport patterns)

For this factor, EPA considered data from National Weather Service
instruments and other meteorological monitoring sites in the area.  Wind
direction and wind speed data for 2005-2007 were analyzed, with an
emphasis on “high PM2.5 days” for each of two seasons, an
October-April “cold” season and a May-September “warm” season. 
These high days are defined as days where any FRM or FEM air quality
monitors had 24-hour PM2.5 concentrations above 95% on a frequency
distribution curve of PM2.5 24-hour values.

For each air quality monitoring site, EPA developed a “pollution
rose” to understand the prevailing wind direction and wind speed on
the days with highest fine particle concentrations.  The figure
identifies 24-hour PM2.5 values by color; days exceeding 35 μg/m3 are
denoted with a red or black icon.  A dot indicates the day occurred in
the warm season; a triangle indicates the day occurred in the cool
season.  The center of the figure indicates the location of the air
quality monitoring site, and the location of the icon in relation to the
center indicates the direction from which the wind was blowing on that
day.  An icon that is close to the center indicates a low average wind
speed on that day.  Higher wind speeds are indicated when the icon is
further away from the center.

The pollution rose for the Paducah area is below as Figure 2.  Winds on
high concentration days are generally quite low and come from the
southwest and northeast slightly more frequently than other directions. 
Still, the wind direction is varied.  So, it is appropriate to include
counties in all directions from the violations.  When considered along
with speciation monitoring data showing that most of the high days are
in the warm season with high sulfate levels, this meteorological
information indicates that certain high days may occur under stagnant
conditions.

 

Figure 2

Note:  the meteorology factor is also considered in each county’s
Contributing Emissions Score because the method for deriving this metric
included an analysis of trajectories of air masses for high PM2.5 days.

Factor 7:  Geography/topography (mountain ranges or other air basin
boundaries)

The geography/topography analysis evaluates the physical features of the
land that might have an effect on the air shed and, therefore, on the
distribution of PM2.5 over the area.

The Paducah area does not have any geographical or topographical
barriers significantly limiting air-pollution transport within its air
shed.  Therefore, this factor did not play a significant role in the
decision-making process.

Factor 8:  Jurisdictional boundaries

In evaluating the jurisdictional boundary factor, EPA gave special
consideration to areas that were already designated nonattainment in
2005 for violating the 1997 fine particle standards.  However, this area
was designated attainment for the 1997 standards, so nonattainment area
boundaries for the 1997 standards were not a factor in determining this
area’s boundaries.

The Paducah maintenance area from its former one-hour ozone designation
is comprised of Livingston and Marshall Counties in Kentucky.  No
portion of Illinois was in the Paducah ozone nonattainment area.  This
factor did not play a significant role in the decision-making process.

Factor 9:  Level of control of emission sources 

Under this factor, the existing level of control of emission sources is
taken into consideration.  The emissions data used by EPA in this
technical analysis and provided in Table 1 under Factor 1 represent
emissions levels taking into account any control strategies implemented
in the Paducah area before 2005 on stationary, mobile, and area sources.
 Data are presented for PM2.5 components that are directly emitted,
carbonaceous PM2.5 and crustal PM2.5, and for pollutants which react in
the atmosphere to form fine particles such as SO2, NOx, VOC, and
ammonia.  

In considering county-level emissions, EPA used data from the 2005
National Emissions Inventory, the most updated version of the national
inventory available at the beginning of the designations process in late
2007.  However, EPA recognized that for certain counties, emissions may
have changed since 2005.  For example, certain power plants or large
sources of emissions in or near this area may have installed emission
controls or otherwise significantly reduced emissions since 2005.  Some
States provided updated information on emissions and emission controls
in their comments to EPA.  EPA considered such additional information in
making final designation decisions.  

With regard to nearby power plants, EPA considered information about
whether a specific plant installed federally enforceable emission
controls by December 2008 resulting in significant emissions reductions.
 A control requirement is considered to be federally-enforceable if it
is required by a State regulation adopted in a State implementation
plan, if it is included in a federally-enforceable Title V operating
permit, or if it is required by a consent decree which also requires the
controls to be included in federally enforceable permit upon termination
of the consent decree.  In making final decisions, EPA also considered
whether a facility would continue to emit pollutants which contribute to
PM2.5 exceedances even after emission controls are operational. 

Illinois provided information on the Joppa Steam Plant in Massac County,
Illinois.  The Joppa Steam Plant plans to install emission controls
between 2010 and 2014.  The planned controls will reduce sulfur dioxide,
nitrogen oxides, and fine particulate emissions.  Low NOx burners and a
baghouse are currently in use at the Joppa plant. 

Still, current emissions from the plant (more than 25,000 tons SO2 and
5000 tons NOx annually) are high enough to warrant inclusion of the
plant as a partial county area in the Paducah nonattainment area.

EPA Technical Analysis for Saint Louis, MO-IL 

EPA reviewed relevant information for the nine counties including four
Illinois counties partly or fully within the area designated
nonattainment in St. Louis for the 1997 PM2.5 standards as well as for
surrounding counties.  There are violating monitors in Madison County,
Illinois.  Illinois recommended a definition of the nonattainment area
for the 2006 standards that is similar to the boundaries that were
established for the 1997 standards, including Madison, Monroe and St.
Clair Counties along with a portion of Randolph County, Illinois. 
Illinois recommended that the nonattainment area for the 2006 standards
differ from the nonattainment area for the 1997 standards by the
exclusion of the portion of Baldwin Township in Randolph County that is
west of the Kaskaskia River.  

EPA concurs with Illinois’s recommendation to include Madison, Monroe,
and St. Clair Counties in the St. Louis nonattainment area.  However,
EPA believes that all of Baldwin Township of Randolph County should be
included as well.  The most important factor influencing this judgment
is the factor relating to jurisdictional boundaries.  The inclusion of a
full township will make nonattainment requirements easier to administer,
since information on emissions and source locations are more readily
available on a township basis than with respect to a specially defined
subset of the township.  Furthermore, EPA believes that establishment of
a nonattainment area that fully matches the nonattainment area
established for the 1997 standards would simplify nonattainment planning
by assuring that identical requirements apply for an identical area.  At
the same time, as addressed in more detail in our documentation of our
designations for the 1997 standards, Baldwin Township contains almost
all of the emissions and therefore makes almost the entirety of the
contribution of Randolph County to the violations, so that a designation
of just Baldwin Township as nonattainment will suffice to address the
contribution of this portion of the area.  As discussed below, Randolph
County does not rank high for any factors other than emissions,
indicating that only Baldwin County where the power plant is located is
appropriate for inclusion in the nonattainment area.

The most significant emissions in Baldwin Township are from Ameren’s
Baldwin Station.  This plant is subject to a consent decree requiring
significant SO2 emission reductions between 2010 and 2012.  Emissions at
this plant also reflect the use of lower sulfur coal than had been
burned in previous decades.  Nevertheless, current emissions remain
relatively high.  Baldwin Township is also fairly nearby to violations
and is commonly upwind of those violations.  Therefore, EPA concluded
that Baldwin Township is currently contributing to violations of the
standard.

EPA reviewed the relevant information for other counties within the
combined statistical area as well as counties adjacent to the combined
statistical area in order to determine the appropriate nonattainment
area.  Sangamon County has moderate emissions but is rarely upwind on
days with elevated 24-hour PM2.5 concentrations.  Other Illinois
counties in or near the combined statistical area have relatively low
emissions, and no other factor warranted inclusion of any of the
counties in the nonattainment area.

Figure 1 is a map of the counties in the nonattainment area and other
relevant information such as the locations and design values of air
quality monitors, and the metropolitan area boundary. 

 

Figure 1

For this area, EPA previously established PM2.5 nonattainment boundaries
for the 1997 PM2.5 NAAQS that included nine full and partial counties,
with four being located in Illinois and five in Missouri including the
city of St. Louis.

In its December 18, 2007 letter, Illinois recommended similar full and
partial counties in the St. Louis area be designated as
“nonattainment” for the 2006 24-hour PM2.5 standard based on air
quality data from 2004-2006.  Illinois recommended a smaller partial
county area that would exclude a portion of Baldwin Township in Randolph
County from the nonattainment area.  The power plant is in the portion
Illinois recommended as nonattainment.  These data are from Federal
Reference Method (FRM) monitors located in the state.

In August 2008, EPA notified Illinois and Missouri of its intended
designations.  In this letter, EPA also requested that if the State
wished to provide comments on EPA’s intended designation, it should do
so by October 20, 2008.  EPA stated that it would consider any
additional information (e.g., on power plants or partial county areas)
provided by the state in making final decisions on the designations.  

Based on EPA's technical analysis described below, EPA has designated
three full counties and one partial county in Illinois and four counties
and a city in Missouri as nonattainment for the 24-hour PM2.5
air-quality standard as the St. Louis nonattainment area, based upon
currently available information.  

		

The following is a review of data for relevant factors for the Saint
Louis area.

Factor 1:  Emissions data

For this factor, EPA evaluated county level emission data for the
following PM2.5 components and precursor pollutants:  “PM2.5 emissions
total,” “PM2.5 emissions carbon,” “PM2.5 emissions other,”
“SO2,” “NOx,” “VOCs,” and “NH3.”  “PM2.5 emissions
total” represents direct emissions of PM2.5 and includes: “PM2.5
emissions carbon,” “PM2.5 emissions other”, primary sulfate (SO4),
and primary nitrate.  (Although primary sulfate and primary nitrate,
which are emitted directly from stacks rather than forming in
atmospheric reactions with SO2 and NOx, are part of “PM2.5 emissions
total,” they are not shown in Table 1 as separate items).  “PM2.5
emissions carbon” represents the sum of organic carbon (OC) and
elemental carbon (EC) emissions, and “PM2.5 emissions other”
represents other inorganic particles (crustal).  Emissions of SO2 and
NOx, which are precursors of the secondary PM2.5 components sulfate and
nitrate, are also considered.  VOCs (volatile organic compounds) and NH3
(ammonia) are also potential PM2.5 precursors and are included for
consideration. 

Emissions data were derived from the 2005 National Emissions Inventory
(NEI), version 1.  See
http://www.epa.gov/ttn/naaqs/pm/pm25_2006_techinfo.html.

EPA also considered the Contributing Emissions Score (CES) for each
county.  The CES is a metric that takes into consideration emissions
data, meteorological data, and air quality monitoring information to
provide a relative ranking of counties in and near an area.  Note that
this metric is not the exclusive manner for considering data for these
factors.  A more detailed description can be found at
http://www.epa.gov/ttn/naaqs/pm/pm25_2006_techinfo.html#C.

Table 1 shows emissions of PM2.5 and precursor pollutants components
(given in tons per year) and the CES for violating and potentially
contributing counties in the St. Louis area.  Counties that are part of
the St. Louis nonattainment area for the 1997 PM2.5 NAAQS are shown in
boldface.  Counties are listed in descending order by CES.

Table 1.  PM2.5 24-hour Component Emissions, and CESs. 

County	State Recommended Nonattainment?	CES	PM2.5

emissions 

total	PM2.5

emissions 

carbon	PM2.5

emissions 

other	SO2	NOx

	VOCs

	NH3

Madison, IL	Yes	100	4,945	1,148	3,796	27,320	19,373	15,676	1,393

St. Louis, MO	No	55	4,221	1,707	2,513	29,966	55,605	54,821	2,954

St. Louis City	No	48	1,686	625	1,060	12,171	24,702	20,647	439

St. Clair, IL	Yes	22	1,496	487	1,009	2,142	10,233	10,869	1,281

St. Charles, MO	No	17	3,694	619	3,075	54,561	20,773	12,419	1,182

Jefferson, MO	No	16	2,945	824	2,121	45,574	16,722	9,273	493

Randolph, IL	Partial	9	2,505	306	2,199	24,605	9,384	2,331	993

Montgomery, IL	No	7	2,463	263	2,200	41,131	12,122	2,789	1,055

Franklin, MO	No	5	2,812	621	2,190	56,767	15,595	5,748	1,818

Monroe, IL	Yes	5	744	235	508	293	3,057	2,529	654

Clinton, IL	No	5	923	206	717	506	2,982	2,919	2,890



Within Illinois, emissions are highest in Madison, St. Clair, and
Randolph Counties.  The emissions from Montgomery, Monroe, and Clinton
Counties are moderate.  Based on emission levels and CES values, these
Illinois counties were candidates for a 24-hour PM2.5 nonattainment
designation.

Table 2 provides the data for CES weighting factors.  The trajectory
factors are used in CES calculations to account for seasonal
meteorology.  For the top 10% of days in both the cold and warm seasons,
wind trajectories were run for a 48 hour period preceding the high
monitor reading.  The amount of time the air mass was over a county
within the mixing height was calculated.  The values were scaled so that
the maximum value is 100.  Thus, the county that is most likely to be
upwind of a monitor on a high concentration day in a season is given a
score of 100.  The scores for the other counties will reflect the
relative likelihood of being upwind.  As the concentration of a
pollutant will decrease as it goes further downwind, a distance
weighting factor is also used in calculating the CES.  The distance
factor listed on Table 2 provides the distance from the center of a
county to the center of the violating county.  If a county is violating,
the distance used is the average distance from the center to the county
line.

  Table 2.  CES Factor Data.

County	CES	Trajectory Factor- Cold	Trajectory Factor- Warm	Distance (mi)

Madison, IL	100	85	69	15.0

St. Louis, MO	55	84	61	38.1

St. Louis City, MO	48	100	99	24.0

St. Clair, IL	22	81	100	27.1

St. Charles, MO	17	63	25	47.2

Jefferson, MO	16	54	39	55.4

Randolph, IL	9	41	52	56.3

Montgomery, IL	7	40	10	38.1

Franklin, MO	5	38	8	69.6

Monroe, IL	5	68	76	39.3

Clinton, IL	5	52	60	28.9



Factor 2:  Air quality data 

This factor considers the 24-hour PM2.5 design values (in µg/m3) for
air quality monitors in counties in the St. Louis area based on data for
the 2005-2007 period.  A monitor’s design value indicates whether that
monitor attains a specified air quality standard.  The 24-hour PM2.5
standards are met when the 3-year average of a monitor’s 98th
percentile values are 35 µg/m3 or less.  A design value is only valid
if minimum data completeness criteria are met.  The 24-hour PM2.5 design
values for counties in the St. Louis area are shown in Table 3.

	Table 3.  Air Quality Data

County	State 

Recommended

 Nonattainment?	Design Values

2004-2006

	Design Values

2005-2007



Madison, IL	Yes	39	39

St. Louis, MO	No	32	34

St. Louis City, MO	No	34	35

St. Clair, IL	Yes	33	34

St. Charles, MO	No	32	33

Jefferson, MO	No	32	34

Randolph, IL	Partial	27	30

Franklin, MO	No	0	0

Monroe, IL	Yes	0	0

Montgomery, IL	No	0	0

Clinton, IL	No	0	0



One county (Madison) in Illinois shows a violation of the 24-hour PM2.5
standard.  Therefore, this county was a strong candidate for inclusion
in the St. Louis nonattainment area.  However, this factor alone is not
sufficient to eliminate the other counties in the St. Louis area as
candidates for nonattainment status.  EPA considered each county’s CES
as well as the eight other factors plus other relevant factors or
circumstances when determining which counties to include in the St.
Louis nonattainment area. 

Note:  Eligible monitors for providing design value data generally
include State and Local Air Monitoring Stations (SLAMS) at
population-oriented locations with an FRM monitor.  All data from
Special Purpose Monitors (SPM) using an FRM is eligible for comparison
to the relevant NAAQS, subject to the requirements given in the October
17, 2006 Revision to Ambient Air Monitoring Regulations (71 FR 61236). 
All monitors used to provide data must meet the monitor siting and
eligibility requirements given in 71 FR 61236 to 61328 in order to be
acceptable for comparison to the 24-hr PM2.5 NAAQS for designation
purposes.

Factor 3: Population density and degree of urbanization (including
commercial development)

Table 4 shows the 2005 population for each county in the area being
evaluated, as well as the population density for each county in that
area.  Population data gives an indication of whether it is likely that
population-based emissions might contribute to violations of the 24-hour
PM2.5 standards. 

Table 4.  Population

County	State Recommended Nonattainment?	2005 Population	2005 Population
Density (pop/sq mi)

Madison, IL	Yes	   263,975 	357

St. Louis, MO	No	1,002,258 	1914

St. Louis City, MO	No	  352,572 	5334

St. Clair, IL	Yes	   259,388 	385

St. Charles, MO	No	   329,606 	557

Jefferson, MO	No	   213,011 	321

Randolph, IL	Partial	     33,116 	55

Franklin, MO	No	     98,987 	107

Monroe, IL	Yes	     31,289 	79

Montgomery, IL	No	     30,304 	43

Clinton, IL	No	     36,138 	72



Madison and St. Clair Counties have the largest populations in the
Illinois portion of the St. Louis area and are therefore candidates for
inclusion in the nonattainment area based on this factor.  The
populations of Randolph, Monroe, Montgomery, and Clinton Counties are
smaller with all having fewer than 37,000 residents.

Factor 4: Traffic and commuting patterns 

This factor considers the number of commuters in each county who drive
within or into the St. Louis area, the percent of total commuters in
each county who commute into or within the area, as well as the total
Vehicle Miles Traveled (VMT) for each county in millions of miles (see
Table 5).  A county with numerous commuters is generally an integral
part of an urban area and is likely contributing to fine particle
concentrations in the area.  

Table 5.  Traffic and Commuting Patterns

County	State Recommended Nonattainment?	2005 VMT

(106 mi)	Number Commuting to any violating counties 

	Percent

Commuting to any violating counties 

	Number Commuting into statistical area 	Percent

Commuting into statistical area 

St. Louis, MO	No	    14,165 	3,800 	1 	    493,070 	          99 

St. Charles, MO	No	     3,185 	740 	0 	    147,420 	          99 

St. Louis City	No	     3,638 	1,250 	1 	    139,280 	          99 

Madison, IL	Yes	     2,318 	75,490 	62 	    119,590 	          98 

St. Clair, IL	Yes	     3,019 	7,040 	6 	    110,870 	          98 

Jefferson, MO	No	     2,241 	490 	1 	      96,860 	          99 

Franklin, MO	No	     1,436 	150 	0 	      43,600 	          97 

Clinton, IL	No	        378 	1,600 	9 	      14,760 	          87 

Monroe, IL	Yes	        359 	420 	3 	      13,560 	          95 

Randolph, IL	Partial	        261 	180 	1 	        2,790 	          21 

Montgomery, IL	No	        525 	290 	2 	        1,300 	          10 



The listing of counties on Table 5 reflects a ranking based on the
number of people commuting to other counties.  The counties that are in
the nonattainment area for the 1997 PM2.5 NAAQS are shown in boldface. 
The counties that comprise the 1997 standards area remain highly
integrated into the St. Louis area.  Most commuters traveled within the
St. Louis area.  Clinton County has low annual VMT and a modest number
of workers who commute into violating counties.  A modest number of
Randolph County commuters traveled into the St. Louis metropolitan area.
 Even fewer Montgomery County commuters travel into the area. 

Note:  The 2005 VMT data used for table 5 and 6 of the 9-factor analysis
has been derived using methodology similar to that described in
“Documentation for the final 2002 Mobile National Emissions Inventory,
Version 3, September 2007, prepared for the Emission Inventory Group,
U.S. EPA.  This document may be found at:
ftp://ftp.epa.gov/EmisInventory/2002finalnei/documentation/mobile/2002_m
obile_nei_version_3_report_092807.pdf.  The 2005 VMT data were taken
from documentation which is still draft, but which should be released in
2008.

Factor 5:  Growth rates and patterns  

This factor considers population growth for 2000-2005 and growth in
vehicle miles traveled for 1996-2005 for counties in the St. Louis area,
as well as patterns of population and VMT growth.  A county with rapid
population or VMT growth is generally an integral part of an urban area
and likely to be contributing to fine particle concentrations in the
area.

Table 6 below shows population, population growth, VMT, and VMT growth
for counties that are included in the St. Louis area.  Counties are
listed in descending order based on VMT growth between 1996 and 2005.

Table 6.  Population and VMT Growth and Percent Change.

County	Population (2005)	Population % change (2000-2005)	2005 VMT

(106 mi)	VMT % 

change

(1996-2005)

Monroe, IL	     31,289 	13 	        359 	          47 

St. Louis, MO	 1,002,258 	-1	    14,165 	          33 

St. Charles, MO	    329,606 	15 	     3,185 	          28 

Montgomery, IL	     30,304 	-1	        525 	          27 

Franklin, MO	     98,987 	5 	     1,436 	          19 

St. Clair, IL	    259,388 	1 	     3,019 	          13

Clinton, IL	     36,138 	2 	        378 	          11 

Randolph, IL	     33,116 	-2	        261 	            2 

Jefferson, MO	    213,011 	7 	     2,241 	            1

St. Louis City, MO	    352,572 	2 	     3,638 	          -8

Madison, IL	    263,975 	2 	     2,318 	          -12 



The counties that experienced the highest growth rates are some of the
smaller counties, such as Monroe County, Illinois.  Thus, the growth
rates are not expected to yield significant changes in the distribution
of population in the area, so this factor did not significantly
influence the decision-making process.

Factor 6:  Meteorology (weather/transport patterns)

For this factor, EPA considered data from National Weather Service
instruments and other meteorological monitoring sites in the area.  Wind
direction and wind speed data for 2005-2007 were analyzed, with an
emphasis on “high PM2.5 days” for each of two seasons, an
October-April “cold” season and a May-September “warm” season. 
These high days are defined as days where any FRM or FEM air quality
monitors had 24-hour PM2.5 concentrations above 95% on a frequency
distribution curve of PM2.5 24-hour values.

For each air quality monitoring site, EPA developed a “pollution
rose” to understand the prevailing wind direction and wind speed on
the days with highest fine particle concentrations.  The figure
identifies 24-hour PM2.5 values by color; days exceeding 35 μg/m3 are
denoted with a red or black icon.  A dot indicates the day occurred in
the warm season; a triangle indicates the day occurred in the cool
season.  The center of the figure indicates the location of the air
quality monitoring site, and the location of the icon in relation to the
center indicates the direction from which the wind was blowing on that
day.  An icon that is close to the center indicates a low average wind
speed on that day.  Higher wind speeds are indicated when the icon is
further away from the center.

The pollution rose for the St. Louis area is provided below in Figure 2.
 Emissions from the southwest and southeast are most prone to contribute
to nonattainment.  Thus, Monroe, St. Clair, Madison and Randolph
Counties in Illinois are appropriate for consideration under this
factor. 

 

Figure 2

Note:  the meteorology factor is also considered in each county’s
Contributing Emissions Score because the method for deriving this metric
included an analysis of trajectories of air masses for high PM2.5 days.

Factor 7:  Geography/topography (mountain ranges or other air basin
boundaries)

The geography/topography analysis evaluates the physical features of the
land that might have an effect on the air shed and, therefore, on the
distribution of PM2.5 over the area.

The St. Louis area does not have any geographical or topographical
barriers significantly limiting air-pollution transport within its air
shed.  Therefore, this factor did not play a significant role in the
decision-making process.

Factor 8:  Jurisdictional boundaries

In evaluating the jurisdictional boundary factor, EPA gave special
consideration to areas that were already designated nonattainment in
2005 for violating the 1997 fine particle standards.  Analysis of
chemical composition data in these areas indicates that the same
components that make up most of the PM2.5 mass in the area on an annual
average basis such as sulfate and direct PM2.5 carbon in many eastern
areas also are key contributors to the PM2.5 mass on days exceeding the
24-hour PM2.5 standard.  These data indicate that in many cities, the
same source categories that contribute to violations of the annual
standard also contribute to exceedances of the 24-hour standard.  

Most areas that were originally designated nonattainment for the PM2.5
standards still have not attained the air quality standards.  Thus, EPA
has generally concluded that counties that were designated as having
emissions sources contributing to fine particle concentrations which
continue to exceed the 1997 standards (all areas violated the annual
standard, two also violated the previous 24-hour standard) also
contribute to fine particle concentrations on the highest days.  For
this reason, EPA believes that for most existing nonattainment areas,
the nonattainment area for the 2006 24-hour standard should be the same.
 Consideration also should be given to existing boundaries and
organizations as they may facilitate air quality planning and the
implementation of control measures to attain the standard.  Areas
already designated as nonattainment represent important boundaries for
state air quality planning.

As noted, Madison, St. Clair, Monroe and a portion (Baldwin Township) of
Randolph Counties are included in the PM2.5 nonattainment area for the
1997 standards.  Under this factor it is appropriate to consider these
same counties for designation for the 2006 standards.

The Ease-West Gateway Council of Governments (EWGCG) is the Metropolitan
Planning Organization (MPO) for the bi-state St. Louis area.  The EWGCG
web site is:   HYPERLINK "http://www.ewgateway.org/" 
http://www.ewgateway.org/ .

The Illinois portion of the St. Louis ozone nonattainment area consists
of Jersey, Madison, Monroe, and St. Clair Counties.

Factor 9:  Level of control of emission sources 

Under this factor, the existing level of control of emission sources is
taken into consideration.  The emissions data used by EPA in this
technical analysis and provided in Table 1 under Factor 1 represent
emissions levels taking into account any control strategies implemented
in the St. Louis area before 2005 on stationary, mobile, and area
sources.  Data are presented for PM2.5 components that are directly
emitted, carbonaceous PM2.5 and crustal PM2.5, and for pollutants which
react in the atmosphere to form fine particles such as SO2, NOx, VOC,
and ammonia.  

In considering county-level emissions, EPA used data from the 2005
National Emissions Inventory, the most updated version of the national
inventory available at the beginning of the designations process in late
2007.  However, EPA recognized that for certain counties, emissions may
have changed since 2005.  For example, certain power plants or large
sources of emissions in or near this area may have installed emission
controls or otherwise significantly reduced emissions since 2005.  Some
States provided updated information on emissions and emission controls
in their comments to EPA.  EPA considered such additional information in
making final designation decisions.  

With regard to nearby power plants, EPA considered information about
whether a specific plant installed federally enforceable emission
controls by December 2008 resulting in significant emissions reductions.
 A control requirement is considered to be federally-enforceable if it
is required by a State regulation adopted in a State implementation
plan, if it is included in a federally-enforceable Title V operating
permit, or if it is required by a consent decree which also requires the
controls to be included in federally enforceable permit upon termination
of the consent decree.  In making final decisions, EPA also considered
whether a facility would continue to emit pollutants which contribute to
PM2.5 exceedances even after emission controls are operational. 

No information was provided regarding recent emission controls installed
at power plants or any other large sources in the Illinois portion of
the St. Louis area.  Thus, this factor was not significant in
determining the boundary of the nonattainment area.

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and St. Clair Counties were shown to be nonattainment candidates based
on several of the factors.  The emissions from the partial county area
in Randolph County combined with the county being low for other factors
including population and commuting made EPA determine a partial county
designation was reasonable.

 

 EPA designated nonattainment areas for the 1997 fine particle standards
in 2005.  In 2006, the 24-hour PM2.5 standard was revised from 65
micrograms per cubic meter (average of 98th percentile values for 3
consecutive years) to 35 micrograms per cubic meter; the level of the
annual standard for PM2.5 remained unchanged at 15 micrograms per cubic
meter (average of annual averages for 3 consecutive years).  

 PAGE   

 PAGE   1 

 Figure 1. Paducah-Mayfield, KY-IL 24-hr PM2.5 Nonattainment Area

