Wisconsin Area Designations For the 

24-Hour Fine Particle National Ambient Air Quality Standard

The table below identifies the counties in Wisconsin that EPA has
designated as not attaining the 2006 24-hour fine particle (PM2.5)
standard.  The nonattainment areas include any tribal lands within the
identified areas.  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 	Wisconsin Recommended Nonattainment Counties	EPA’s Designated
Nonattainment Counties

Green Bay	None	Brown

Madison	None	Columbia* (partial)

Dane

Milwaukee	None	Milwaukee

Racine

Waukesha



EPA is designating the remaining counties or portions thereof in the
state as “attainment/unclassifiable.”  

*Within Columbia County, EPA is designating only Pacific Township as
part of the Madison nonattainment area.

EPA Technical Analysis for Green Bay, Wisconsin 

The Green Bay area is currently designated attainment for PM2.5.  One
monitor in Brown County is clearly showing a violation of the standard,
and an additional monitor with incomplete data may also be indicating a
violation.  Despite these violations, Wisconsin recommended that the
Green Bay area be designated attainment, based on projections that the
area will attain the standards by 2015.  However, the Clean Air Act
requires that EPA designate as nonattainment any area that is currently
violating the standard or contributing to such violation, irrespective
of whether the area is expected to attain the standard at some time in
the future.  Therefore, EPA reviewed relevant information for the three
counties in the metropolitan statistical area and for surrounding
counties to determine the most appropriate boundaries for the area in
and around Green Bay to be designated nonattainment.

EPA determined that the appropriate nonattainment area consists of Brown
County.  Brown County has substantially greater emissions and more
population than any surrounding county.  While Outagamie County has
moderate emissions and population similar to that of Brown County, these
emissions and this population are primarily associated with Appleton,
which is a separate urban area that is monitoring attainment of the
standard.  Only a small fraction of commuters from the Appleton area
commute into the Green Bay area.  Appleton is at the southern end of
Outagamie County, further reducing its impact on concentrations in Green
Bay, at the northern end of Brown County.  No other factor warrants
inclusion of any other county besides Brown County 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 December 18, 2007 letter, Wisconsin recommended that no counties
be designated as “nonattainment” for the 2006 24-hour PM2.5
standard.

In August 2008, EPA notified Wisconsin 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 designated one
Wisconsin county as nonattainment for the 24-hour PM2.5 air-quality
standard as the Green Bay nonattainment area, based upon currently
available information.

The following is a review of data for relevant factors for the Green
Bay, Wisconsin 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 Green Bay area.  Counties that are part of
the Green Bay 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

(tpy)	PM2.5

emissions 

carbon

(tpy)	PM2.5

emissions 

other

(tpy)	SO2

(tpy)	NOx

(tpy)	VOCs

(tpy)	NH3

(tpy)

Brown, WI	No	100	2,541	879	1,662	29,780	24,197	18,272	3,295

Outagamie, WI	No	22	1,525	632	894	11,572	9,663	11,671	3,090

Manitowoc, WI	No	12	949	348	600	4,392	5,831	5,893	3,111

Kewaunee, WI	No	4	371	127	244	277	1,258	2,116	1,966

Oconto, WI	No	2	445	227	218	151	1,588	3,868	1,698



Brown County has the highest CES and emissions in the area.  Outagamie
County is the next highest in emissions and CES.  Outagamie County is in
the Appleton metropolitan statistical area.  The other area counties
have low emissions. 

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)

Brown	100	100	99	12.4

Outagamie	22	87	83	24.2

Manitowoc	12	84	97	25.2

Kewaunee	4	75	83	17.7

Oconto	2	65	50	42.2



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 Green Bay area based on data for
the 2005-2007 period.  These data are from Federal Reference Method
(FRM) monitors.  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 Green Bay area are
shown in Table 3.  

	Table 3.  Air Quality Data

County	State 

Recommended

 Nonattainment?	Design Values

2004-2006

	Design Values

2005-2007

Brown, WI	No	37	37

Kewaunee, WI	No



Oconto, WI	No



Outagamie, WI	No	34	34

Manitowoc, WI	No	29	32



Brown County has a 2005-2007 design value that exceeds the 2006 PM2.5
standards.  Outagamie and Manitowoc Counties meet the air quality
standards.  Kewaunee and Oconto Counties do not have PM2.5 air quality
monitoring data.

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 Green Bay area occur about 22% in the
warm season and 78% in the cool season.  In the warm season, the average
chemical composition of the highest days is 72% sulfate, no nitrate, 24%
carbon, and 3% crustal.  In the cool season, the average chemical
composition of the highest days is 34% sulfate, 34% nitrate, 29% carbon,
and 3% crustal.  These data indicate that sources of SO2, NOx, and
direct PM2.5 emissions contribute to violations in the area.

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.  Brown County has the highest population.  Kewaunee and
Oconto Counties have small populations.  Outagamie County has moderate
population, but its population density is well less than the Brown
County population density.  

Table 4.  Population

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

Brown, WI	No	    238,610 	447

Kewaunee, WI	No	     20,746 	60

Oconto, WI	No	     37,727 	37

Outagamie, WI	No	    170,930 	266

Manitowoc, WI	No	     81,828 	138



Factor 4: Traffic and commuting patterns 

This factor considers the number of commuters in each county who drive
to another county within the Green Bay area, the percent of total
commuters in each county who commute within the area, and 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/to
statistical area 	Percent

Commuting within/to statistical area 

Brown, WI	No	    2,643 	108,890 	92 	    110,410 	          93 

Oconto, WI	No	       413 	6,520 	38 	      15,330 	          88 

Outagamie, WI	No	    1,750 	5,570 	7 	        5,630 	            7 

Kewaunee, WI	No	       234 	3,450 	33 	        9,370 	          89 

Manitowoc, WI	No	    1,130 	1,580 	4 	        1,870 	            4 



The listing of counties on Table 5 reflects a ranking based on the
number of people commuting within or into the Green Bay area.  The
commuting within or into the statistical area data shows a high percent
of commuting in Brown, Kewaunee, and Oconto Counties while Outagamie and
Manitowoc Counties have limited commuting.  This suggests that Brown,
Kewaunee, and Oconto Counties are integrated.  It also implies that
there is not a strong relationship between Outagamie and Manitowoc
Counties workers and the Green Bay area, reflecting the fact that
Appleton (Outagamie County) and Manitowoc (Manitowoc County) are
separate urban areas from Green Bay.  The VMT is low in Kewaunee and
Oconto Counties.   

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 Green Bay 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 Green Bay 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)

Kewaunee, WI	     20,746 	3 	        234 	          35 

Outagamie, WI	    170,930 	6 	     1,750 	          29 

Brown, WI	    238,610 	5 	     2,643 	          28 

Oconto, WI	     37,727 	5 	        413 	          24 

Manitowoc, WI	     81,828 	-1	     1,130 	          15 



There was moderate population growth for all the area counties with the
exception of Manitowoc County.  Manitowoc County experienced a small
decrease in its population from 2000 to 2005.  The VMT grew a high rate
through the area.  Kewaunee County led with a 35% increase from 1996 to
2005 to its small VMT.  Brown and Outagamie Counties follow closely with
VMT growth approaching 30%.  The other counties also observed rapid VMT
growth.  These data suggest that the distribution of population and
emissions are not changing in a way that would significantly influence
the choice of boundaries of the nonattainment area.

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 Green Bay area is provided as Figure 2. 
Winds on high concentration days show a slight tendency to come from the
South to Southwest.  

 

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 Green Bay 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 metropolitan planning organization for Green Bay is the Brown County
Planning Commission.  Its web site is   HYPERLINK
"http://www.co.brown.wi.us/planning_and_land_services/" 
http://www.co.brown.wi.us/planning_and_land_services/ 
planning/county_web//transportation.html. 

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 Green Bay 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 did not provide additional information regarding power plants
or other large sources in the Green Bay area. 

EPA Technical Analysis for Madison, Wisconsin 

The Madison area is currently designated attainment for PM2.5.  One
monitor in Dane County is showing a violation of the standard based on
2005 to 2007 data.  Wisconsin did not acknowledge this violation and
made no recommendations specifically addressing this nonattainment area.
 Therefore, EPA reviewed relevant information for the four counties in
the metropolitan statistical area and for surrounding counties to
determine the most appropriate boundaries for the area in and around
Madison to be designated nonattainment.

EPA is designating a Madison nonattainment area that includes Dane
County and Pacific Township within Columbia County.  Dane County is
recording a violation, and the full county contributes to that
violation.  Columbia County does not have a monitor, and upon further
review, EPA finds that only a portion of Columbia County contributes to
the violation in Dane County.

Emissions in Columbia County are dominated by the emissions of a power
plant known as Columbia Station.  This plant emits by far most of the
sulfur dioxide emitted in the Madison area, and the plant also emits a
significant fraction of the nitrogen oxides emitted in the area.  The
remainder of Columbia County has almost no SO2 emissions and
significantly less emissions than Dane County of other pollutants as
well.  The population of Columbia County is only 12 of the population of
Dane County.  Thus, EPA has judged that portions of Columbia County
other than Pacific Township do not contribute to the violations in Dane
County, and EPA has judged that Pacific Township, containing Columbia
Station, is the only portion of Columbia County that contributes to the
violations in Dane County.

The other counties in and near the Madison area have substantially lower
emissions, and no other factor warrants inclusion of any other county
besides Columbia and Dane 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 April 2008, EPA notified Wisconsin that a monitor in the Madison area
was violating based on 2005-2007 data.  In August 2008, EPA notified
Wisconsin 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.  

In its October 20, 2008 letter, Wisconsin provided EPA with a
recommendation of attainment for this area.  Wisconsin considers that
Dane County is meeting the 2006 24-hour PM2.5 standard based projects of
future air quality.  Dane County is currently monitoring nonattainment
for the 2006 24-hour PM2.5 standard based on air quality data from
2005-2007.  

Based on EPA's technical analysis described below, EPA has designated
one full and one partial county in the Wisconsin as nonattainment for
the 24-hour PM2.5 air-quality standard as part of the Madison
nonattainment area, based upon currently available information.

The following is a review of data for relevant factors for the Madison,
Wisconsin 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 Madison area.  Counties that are part of
the Madison 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



Dane, WI	No	 100	4,263	1,700	2,562	8,717	18,818	29,797	5,091

Columbia, WI	No	 36	1,281	373	908	26,406	11,514	6,718	2,321

Sauk, WI	No	 7	902	410	493	365	2,936	5,309	2,601

Iowa, WI	No	 3	364	141	223	97	1,024	2,132	2,572



The CES show that Dane County has distinctly higher emissions than
nearby counties, except for the higher SO2 emissions of Columbia County.
 Columbia County has a CES that trails well below Dane County, but it
still has substantial emissions.  Columbia County has the highest sulfur
dioxide emissions in the area.  Most of Columbia County’s emissions
come from a single facility.  Thus, it was appropriate to designate a
partial county area containing the power plant as nonattainment.  The
CES and emissions are low in Iowa and Sauk 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.  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)

Dane, WI	 100	100	93	19.6

Columbia, WI	 36	66	62	28.0

Sauk, WI	 7	56	61	32.7

Iowa, WI	 3	68	76	36.1



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 Madison area based on data for
the 2005-2007 period.  These data are from Federal Reference Method
(FRM) monitors.  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 Madison area are
shown in Table 3.  Dane County has a 2005-2007 design value that
violates the 2006 standards while Sauk County monitoring data shows it
meets the standards.  There is no PM2.5 air quality monitoring data for
Columbia and Iowa Counties.  

	Table 3.  Air Quality Data

County	State 

Recommended

Nonattainment?	Design Values

2004-2006	Design Values

2005-2007

Dane, WI	No	35	37

Columbia, WI	No



Sauk, WI	No	29	28

Iowa, WI	No





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 Madison area occur about 26% in the warm
season and 74% in the cool season.  In the warm season, the average
chemical composition of the highest days is 72% sulfate, no nitrate, 24%
carbon, and 3% crustal.  In the cool season, the average chemical
composition of the highest days is 34% sulfate, 34% nitrate, 29% carbon,
and 3% crustal.  These data indicate that sources of SO2, NOx, and
direct PM2.5 emissions contribute to violations in the area.  Sources of
these types of emissions are located throughout the seven counties that
EPA has concluded should be designated nonattainment for the 2006 PM2.5
NAAQS. 

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 give an indication of whether it is likely that
population-based emissions might contribute to violations of the 24-hour
PM2.5 standards.  Dane County easily has the largest population and the
highest population density in the Madison area.  Columbia, Iowa, and
Sauk Counties all have small populations.

Table 4.  Population

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

Dane, WI	No	    458,333 	371

Columbia, WI	No	     55,122 	69

Sauk, WI	No	     57,738 	68

Iowa, WI	No	     23,535 	31



Factor 4: Traffic and commuting patterns 

This factor considers the number of commuters in each county who drive
to another county within the Madison area, the percent of total
commuters in each county who commute within the area, and 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 

Dane, WI	No	    4,584 	229,390 	95 	    233,440 	          96 

Sauk, WI	No	       706 	3,430 	12 	      27,460 	          96 

Columbia, WI	No	       916 	8,930 	33 	      24,810 	          92 

Iowa, WI	No	       266 	3,160 	26 	      11,490 	          93 



The listing of counties on Table 5 reflects a ranking based on the
number of people commuting within the statistical area.  Dane County has
the highest VMT in the area.  The other counties all have much lower
VMT.  Columbia County has a moderate percent of commuters going to Dane
County, the violating county.  The number of Columbia County commuters
is still small when compared with Dane County.  The VMT and commuting to
a violating county statistics are low for Iowa and Columbia Counties.

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 Madison 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 Madison area.  Counties are listed
in descending order based on VMT growth between 1996 and 2005.  Dane
County experienced the most growth in both population and VMT.  All area
counties had limited growth from 2000 to 2005.  Dane County had VMT
growth that exceeded 20% from 1996 to 2005.  Columbia and Iowa had
better than 10% VMT growth over that period.  Sauk County had a little
less VMT growth.  These data suggest that the distribution of population
and emissions are not changing in a way that would significantly
influence the choice of boundaries of the nonattainment area.

Table 6.  Population and VMT Growth and Percent Change.

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

(106 mi)	VMT

% change

(1996-2005)

Dane, WI	    458,333 	7 	     4,584 	          21 

Iowa, WI	     23,535 	3 	        266 	          15 

Columbia, WI	     55,122 	5 	        916 	          11 

Sauk, WI	     57,738 	4 	        706 	            8 



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 Madison area is provided as Figure 2.  Winds
on high and moderate concentration days come from a variety of
directions.  So, counties in all directions from the violations in Dane
County were considered.

 

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 Madison 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 Madison Area Transportation Board is the metropolitan planning
organization for Dane County, Wisconsin.  Its web site is   HYPERLINK
"http://www.madisonareampo.org"  www.madisonareampo.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 Madison 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 did not provide additional information regarding power plants
or other large sources in the Madison area. 

EPA Technical Analysis for Milwaukee, Wisconsin 

The Milwaukee area is currently designated attainment for PM2.5. 
Several monitors in Milwaukee County are showing violations of the
standard, several of which are well above the standard.  Despite these
violations, Wisconsin recommended that the Milwaukee area be designated
attainment, based on projections that the area will attain the standards
by 2015.  However, the Clean Air Act requires that EPA designate as
nonattainment any area that is currently violating the standard or
contributing to such violation, irrespective of whether the area is
expected to attain the standard at some time in the future.  Therefore,
EPA reviewed relevant information for the five counties in the combined
statistical area and for surrounding counties to determine the most
appropriate boundaries for the area in and around Milwaukee to be
designated nonattainment.

EPA is designating a Milwaukee nonattainment area consisting of
Milwaukee, Racine, and Waukesha Counties.  As noted above, Milwaukee
County is observing violations at multiple locations.  Waukesha County
has relatively high emissions, and the winds commonly blow these
emissions into Milwaukee County on high concentration days.  Waukesha
also has substantial population, a high percentage of which population
commutes into Milwaukee County.  Racine County also has relatively high
emissions which commonly blow into Milwaukee County.

EPA has judged that Kenosha, Ozaukee, and Washington Counties do not
contribute to violations in the nonattainment area.  The 2005 emissions
inventory shows high emissions in Kenosha County, but these 2005
emissions were attributable in large part to the WEPCO Pleasant Prairie
power plant.  By the end of 2006, this plant had highly effective NOx
control equipment in place on both units, and by the end of 2007 the
plant had highly effective SO2 control equipment in place on both units.
 As a result, Kenosha County now has relatively low emissions which EPA
believes no longer contribute to violations in Milwaukee County.  A
federally enforceable consent decree, which must be replaced with a
permit establishing the same requirements before the terms of the
consent decree expire, assures that these emissions will remain low. 
Ozaukee and Washington Counties have moderate emissions and a moderate
fraction of the commuters from these counties commute into Milwaukee
County.  However, the population in these counties is lower than the
population in Milwaukee, Racine, and Waukesha Counties, the frequency
with which the wind blows from these counties into Milwaukee County on
high concentration days is lower, and the emissions are enough lower
than the emissions of Milwaukee, Racine, and Waukesha Counties for EPA
to judge that these counties do not contribute to the violations.  

EPA also reviewed relevant information for counties adjacent to the
combined statistical area in order to determine the appropriate
nonattainment area.  These other counties 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 December 18, 2007 letter, Wisconsin recommended that no counties
be designated as “nonattainment” for the 2006 24-hour PM2.5
standard.

In August 2008, EPA notified Wisconsin 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 designated three
Wisconsin counties as nonattainment for the 24-hour PM2.5 air-quality
standard as the Milwaukee nonattainment area, based upon currently
available information.

The following is a review of data for relevant factors for the
Milwaukee, Wisconsin 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 Milwaukee area.  Counties that are part of
the Milwaukee 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



Milwaukee, WI	No	100	5,802	2,583	3,219	24,239	36,376	48,898	1,181

Waukesha, WI	No	34	2,134	1,132	1,002	1,020	12,168	24,705	893

Kenosha, WI	No	17	1,489	460	1,030	33,988	15,967	7,857	647

Racine, WI	No	12	1,242	547	695	761	5,858	11,809	791

Lake, IL	Other	12	2,657	1,070	1,587	14,719	29,478	32,778	747

McHenry, IL	Other	7	2,102	634	1,468	592	9,493	10,596	1,224

Ozaukee, WI	No	5	841	344	496	377	4,492	5,421	871

Washington, WI	No	5	807	391	416	337	4,090	9,053	1,410



Milwaukee County has the highest emissions for most of the pollutants
and the highest CES in the area.  Waukesha and Racine Counties have
lower emissions and CES.  Still, the emissions and scores indicate that
the counties may contribute the violations in the area.  Kenosha County
also has a moderate CES, but this is due to the high sulfur dioxide
emissions.  The CES was calculated using 2005 emissions data.  As shown
on Table 1, the sulfur dioxide emissions for Kenosha County were the
highest in the area.  Sharp sulfur dioxide emissions reductions,
mandated under a federal consent decree, have occurred at a Kenosha
County power plant which has greatly reduced the county’s impact on
the Milwaukee area violations. 

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)

Milwaukee, WI	100	100	100	8.1

Waukesha, WI	34	70	88	16.6

Kenosha, WI	17	71	88	30.5

Racine, WI	12	86	97	20.4

Lake, IL	12	51	70	48

McHenry, WI	7	39	59	53.8

Ozaukee, WI	5	58	68	24.2

Washington, WI	5	42	64	27.5



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 Milwaukee area based on data for
the 2005-2007 period.  These data are from Federal Reference Method
(FRM) monitors.  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 Milwaukee area are
shown in Table 3.  

	Table 3.  Air Quality Data

County	State 

Recommended

Nonattainment?	Design Values

2004-2006	Design Values

2005-2007

Milwaukee, WI	No	41	41

Waukesha, WI	No	36	34

Racine, WI	No	0	0

Ozaukee, WI	No	31	34

Washington, WI	No	0	0

Kenosha, WI	No	32	34

Lake, IL	Other	33	35

McHenry, IL	Other	31	31



The design value for Milwaukee County exceeds the 2006 PM2.5 standards. 
The 2004-2006 design value for Waukesha County was above the standard,
but it is now below the standards based on 2005-2007 data.  Kenosha and
Ozaukee Counties also meet the air quality standards.  There are no
PM2.5 air quality data for Racine and Washington Counties.

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 Milwaukee area occur about 27% in the
warm season and 73% in the cool season.  In the warm season, the average
chemical composition of the highest days is 73% sulfate, no nitrate, 24%
carbon, and 3% crustal.  In the cool season, the average chemical
composition of the highest days is 20% sulfate, 58% nitrate, 19% carbon,
and 3% crustal.  These data indicate that sources of SO2, NOx, and
direct PM2.5 emissions contribute to violations in the area.

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.  Milwaukee County has the largest population and
highest population density.  Waukesha County has the next largest
population.  Racine, Kenosha, and Washington Counties follow with lower
populations.  Lake County, Illinois has a significant population, but it
is in the Chicago nonattainment area.

Table 4.  Population

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

Milwaukee, WI	No	    918,673 	3788

Lake, IL	Other	    704,086 	1504

Waukesha, WI	No	    378,804 	654

McHenry, IL	Other	    304,701 	499

Racine, WI	No	    195,219 	574

Kenosha, WI	No	    160,382 	574

Washington, WI	No	    125,928 	289

Ozaukee, WI	No	     85,983 	368



Factor 4: Traffic and commuting patterns 

This factor considers the number of commuters in each county who drive
to another county within the Milwaukee area, the percent of total
commuters in each county who commute within the area, and 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/to
statistical area 	Percent

Commuting within/to statistical area 

Milwaukee, WI	No	    8,924 	402,450 	94 	    419,000 	          98 

Waukesha, WI	No	    3,423 	180,500 	94 	    186,020 	          97 

Racine, WI	No	    1,395 	17,060 	19 	      78,740 	          88 

Washington, WI	No	    1,107 	24,320 	38 	      61,010 	          96 

Ozaukee, WI	No	       967 	17,420 	40 	      41,900 	          96 

Kenosha, WI	No	    1,250 	2,990 	4 	        9,660 	          13 

Lake, IL	Other	    6,016 	950 	0 	        1,430 	            1 

McHenry, IL	Other	    2,104 	130 	0 	           200 	            0 



The listing of counties on Table 5 reflects a ranking based on the
number of people commuting to other counties.  Kenosha County along with
Lake and McHenry Counties in Illinois have rather limited commuting to
the Milwaukee statistical area.  All three counties are in the Chicago
statistical area.  The commuting statistics also show a link between the
other counties as all have a high percent of commuting within the
Milwaukee area.  Milwaukee and Waukesha Counties have the highest number
and percentage of workers who commute to a violating county.

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 Milwaukee 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 Milwaukee 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 (2000-05)	2005 VMT

(106 mi)	VMT

% change

(1996-2005)

McHenry, IL	    304,701 	16 	     2,104 	        196 

Lake, IL	    704,086 	9 	     6,016 	          82 

Kenosha, WI	    160,382 	7 	     1,250 	          12 

Washington, WI	    125,928 	7 	     1,107 	          10 

Ozaukee, WI	     85,983 	4 	        967 	            9 

Racine, WI	    195,219 	3 	     1,395 	            7 

Waukesha, WI	    378,804 	5 	     3,423 	            4 

Milwaukee, WI	    918,673 	-2	     8,924 	            1 



The counties in the Chicago statistical area, Kenosha and Lake and
McHenry, Illinois, have the highest growth rates.  The population and
VMT growth is higher for these three than for the five counties in the
Milwaukee statistical area.  The population growth is limited for the
Milwaukee area counties.  Milwaukee County lost population from 2000 to
2005.  The growth of VMT was moderate for the Milwaukee area counties
from 1996 to 2005.  These data suggest that the distribution of
population and emissions within the Milwaukee area are not changing in a
way that would significantly influence the choice of boundaries of the
nonattainment area.

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. 

 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 Milwaukee area is provided as Figure 2. 
Winds on high and moderate concentration days come from a variety of
directions.  So, counties in all directions from the violations were
considered.

 

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 Milwaukee 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 Southeastern Wisconsin Regional Planning Commission is the
metropolitan planning organization for the Milwaukee area.  Its web site
is   HYPERLINK "http://www.sewrpc.org"  www.sewrpc.org .

The Milwaukee, Wisconsin ozone nonattainment area is composed of
Kenosha, Milwaukee, Ozaukee, Racine, Washington, and Waukesha 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 Milwaukee 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. 

 

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s promulgation of boundaries of areas that currently contribute to
current violations.

 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).  

