Commonwealth of Pennsylvania 

Bureau of Air Quality 

Comments on Pennsylvania’s designation recommendations for the 

revised 2006 24-hour fine-particle (PM2.5) National Ambient Air Quality 

Standard (NAAQS). 

Enclosures 

Enclosure 1: Technical Discussion 

Enclosure 2: EPA Region II’s comments on designation of Warren 

County, New Jersey 

Enclosure 3: Pennsylvania’s enclosure to EPA’s proposed June 29, 2004 

designations for the 1997 PM2.5 NAAQS (2004) 
PA DEP Response to EPA PM2.5 Designations 

October 2008 

Page 1 of 1 

TECHNICAL DISCUSSION 

Inclusion of Knowlton Twp, Warren County, NJ in the Allentown-Bethlehem-Easton 

PM2.5 Nonattainment Area:

The New Jersey Department of Environmental Protection (NJ DEP) has recommended 

that a portion of Warren County be included as part of the Allentown-Bethlehem-Easton, 

PA, PM2.5 nonattainment area. The Department responded to NJ DEP on December 10, 

2007. We continue to believe that Knowlton Township in Warren County, NJ should not 

be included as part of the Allentown-Bethlehem-Easton, PA, PM2.5 nonattainment area. 

The NJ DEP has not demonstrated with Federal Reference Method (FRM) monitoring 

that PM2.5 concentrations within the township exceed the 2006 PM2.5 National Ambient 

Air Quality Standard (NAAQS). In fact, concentrations at the current monitoring site in 

Warren County (Phillipsburg) meet the 2006 PM2.5 NAAQS. This supports positions 

taken by EPA Region II and EPA Region III that Warren County, NJ be designated as an 

attainment county. (See EPA Technical Support Documents, August 14, 2008.) 

The use of modeling results to define nonattainment areas is not supported by current 

EPA guidance regarding the development of nonattainment area recommendations. 

While models have been used in the past to delineate nonattainment areas, as referenced 

in NJ DEP’s April 14, 2008 response to comments document, this technique is not 

specifically mentioned in the Robert Myers June 8, 2007 memorandum (Myers memo) 

regarding the factors that states and tribal organizations should consider when making 

their nonattainment area recommendations. The Myers memo outlined a set of nine 

factors that should be evaluated when developing PM2.5 nonattainment recommendations. 

These were the factors the Commonwealth used to develop its original recommendations 

provided to EPA in December 2007 and were the same factors EPA reviewed when they 

issued their intended nonattainment recommendations in August 2008. Therefore, NJ 

DEP’s modeling results are irrelevant to the final nonattainment designations, a point 

echoed in EPA Region II’s August 14, 2008 technical analysis (Enclosure 1), which 

states: 

“[W]hile the analysis indicates an impact in the Knowlton Township area, EPA 

has determined that there is insufficient information to conclude that the air 

quality violations of the fine particle NAAQS has occurred. Current regulations 

and policy require that violations of the PM2.5 standards be determined on the 

basis of complete, quality-assured ambient air quality monitoring data at a 

monitor in the area. The regulations and policy do not provide for PM2.5 violations 

to be determined through means other than ambient air quality monitoring.” 

New Jersey could have installed FRM monitoring in the township to support its 

recommendation, but chose not to do so. 

The American Lung Association, Earthjustice, Environmental Defense Fund and 

the Natural Resources Defense Council Comments Regarding the Liberty-Clairton 

Nonattainment Area: 
PA DEP Response to EPA PM2.5 Designations 

October 2008 

Page 2 of 2 

The Department agrees with EPA assessment that the Liberty-Clairton area should be its 

own separate area from the Pittsburgh-Beaver Valley nonattainment area. The 

nonattainment problem in the Liberty-Clairton region is a result of the complex 

interaction of a local emission source with meteorology and topography. The local 

source in question is the US Steel-Clairton Coke Works facility. 

Figure 1 (courtesy of Google Maps) shows the US Steel – Clairton Coke Works facility 

with respect to the Liberty monitor. 

Figure 1 
PA DEP Response to EPA PM2.5 Designations 

October 2008 

Page 3 of 3 

Figure 2 shows the terrain differences between the US Steel-Clairton Coke Works facility 

and the hillside across the river. 

Figure 2 

 

Since the Clairton Coke Works plant is to the south of the Liberty monitor, the highest 

PM2.5 levels at Liberty occur when the winds are out of the south-southwest (when the 

winds can blow over the top of the Coke Works and northward toward the monitor). This 

was demonstrated in the support documents for the designations of the 1997 PM2.5 

NAAQS standards (see the excerpt of that assessment on pages 16 to 23 in the attached 

Enclosure 3. This document can also be found on EPA’s website at 

http://www.epa.gov/pmdesignations/1997standards/rec/region3.htm under Appendix 1 of 

PA’s Remarks to EPA’s Response). 

In addition, the American Lung Association comment referenced a report entitled The 

Particulate-Related Health Benefits of Reducing Power Plant Emissions. Their reference 

of this report was to compare the local source of US Steel-Clairton Coke Works to that of 

large sources of particulates, such as power plants. However, the emissions from the 

Clairton Coke Works are much less than those from a power plant. In addition, the 

Clairton Coke Works facility has stack heights that are lower than normal power plant 
PA DEP Response to EPA PM2.5 Designations 

October 2008 

Page 4 of 4 

stacks. This would mean that the effects of a source like the Coke Works would impact 

the ground at a much closer location locally than a power plant. Using Figure 2 above, 

one can see that when the plume rises above the plant (and a southwesterly wind is 

blowing across the region), it would impact the hillside and the Liberty monitor. 

The highest fine particulate concentrations occur at Liberty when we see the southsouthwesterly winds along with a morning inversion. A morning inversion occurs when 

the ground is cooler than the air above it; normally at night, the area is under the control 

of high pressure and clear skies. With the warmer air being above the cooler air, vertical 

mixing is at a minimum. Therefore, anything exhausted in the boundary layer with an 

inversion in place will remain trapped in that layer. For example, as the Coke Works’ low 

level sources emit emissions, the plume of emissions will only rise to the top of the 

inversion layer. At that point, the pollution is spread out horizontally. These inversions 

usually set up only a few hundred feet above the surface. Therefore, fine particulate 

levels can become very high near the surface. In this case, the plume impacts the hillside 

across the river as well; the plume is actually not traveling large distances. This is 

evident from the speciation data from two sites, Liberty and Lawrenceville. The 

Lawrenceville monitor is actually downwind from the Pittsburgh metro area (the monitor 

sits atop the Allegheny County Health Department building in Lawrenceville, which is to 

the west of the Allegheny River). 

 The figures below display the results of the 2003-05 speciated components of the fine 

particulates at these two monitors. 

Figure 3: Lawrenceville Figure 4: Liberty 

 
PA DEP Response to EPA PM2.5 Designations 

October 2008 

Page 5 of 5 

Figure 5 looks at the difference between the Lawrenceville and Liberty monitors, also 

know as the Liberty Excess. 

Figure 5: Liberty Excess 

Regional pollutants, such as sulfates and nitrates, are not showing up in the Liberty 

Excess. In this case, carbon (elemental and organic) is playing a big role in the actual 

PM2.5 measurements at Liberty. The US Steel-Clairton Coke Works facility is a huge 

contributor to elemental and organic carbon. 

Therefore, from the analysis above and from the analysis that EPA provided as part of 

their response to the PA DEP 2006 PM2.5designations recommendation, the Department 

agrees with EPA’s assessment that the Liberty-Clairton area should be a separate 

nonattainment area from the Pittsburgh-Beaver Valley area. 

The American Lung Association, Earthjustice, Environmental Defense Fund and 

the Natural Resources Defense Council Comments Regarding the Use of 

Metropolitan Statistical Areas (MSAs) in Defining PM 2.5 Nonattainment Areas: 

The Department agrees with EPA’s use of the full nine-factor analysis when designating 

areas for nonattainment for fine particulates. One of the nine factors is the “population 

density and degree of urbanization” (the classification of Consolidated Statistical Areas, 

Core Based Statistical Areas and Metropolitan Statistical Areas (MSA) fall under this 

category). Consequently, MSA boundaries were indeed taken into consideration when 

EPA proposed the PM2.5 nonattainment areas. However, other factors, such as 

meteorology, topography and emissions data, play an important role in limiting the size 

of the nonattainment areas. In addition, jurisdictional boundaries, such as existing 

nonattainment boundaries, and traffic and commuting patterns were also considered. 


Attachment 1

NEW JERSEY 

Area Designations For the 

24-Hour Fine Particle National Ambient Air Quality Standard 

The table below identifies the counties in New Jersey that EPA intends to designate as 

not attaining the 2006 24-hour fine particle (PM2.5) standard.1

 A county will be 

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 

New Jersey Recommended 

Nonattainment Counties 

EPA’s Intended 

Nonattainment Counties 

Allentown-BethlehemEaston PA-NJ area Warren County (partial) - 

Knowlton Township 

None 

New York-Northern New 

Jersey-Long Island, NY-NJCT area 

Bergen County, Essex 

County, Hudson County, 

Mercer County, Middlesex 

County, Monmouth County, 

Morris County, Passaic 

County, Somerset County, 

and Union County 

No change 

Philadelphia-Wilmington, 

PA-NJ-DE area 

Burlington County, Camden 

County, and Gloucester 

County 

No change 

EPA intends to designate the remaining counties in the state as 

“attainment/unclassifiable.” 

EPA Technical Analysis for the Allentown-Bethlehem-Easton PA-NJ area 

Discussion 

Pursuant to section 107(d) of the Clean Air Act, EPA must designate as nonattainment 

those areas that violate the NAAQS and those areas that contribute to violations. This 

technical analysis for the Allentown-Bethlehem-Easton PA-NJ (Allentown, PA-NJ) area

 

1 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). 

1
identifies the counties with monitors that violate the 24-hour PM2.5 standard and evaluates 

the counties that potentially contribute to fine particle concentrations in the area. EPA 

has evaluated these counties based on the weight of evidence of the following nine 

factors recommended in EPA guidance and any other relevant information: 

- pollutant emissions 

- air quality data 

- population density and degree of urbanization 

- traffic and commuting patterns 

- growth 

- meteorology 

- geography and topography 

- jurisdictional boundaries 

- level of control of emissions sources 

Figure 1 is a map of the counties in the area and other relevant information such as the 

locations and design values of air quality monitors, the metropolitan area boundary, and 

counties recommended as nonattainment by the State. 

Allentown, PA

Counties labeled in bold reflect NAAs under 1997 NAAQS

34

Figure 1. Map of Allentown, PA area that includes Warren County, NJ

In December 2007, New Jersey recommended that Knowlton Township in Warren 

County be designated as “nonattainment” for the 2006 24-hour PM2.5 standard based on 

2
modeled violations in the Knowlton Township area of Warren County. New Jersey’s 

recommendation was received by EPA on December 18, 2007. 

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 Allentown area occur predominantly in the warm season. The PM2.5 urban 

increment as noted in the below figures is dominated by total carbon in both the warm 

and cold season months (i.e. 79 percent in the warm season, and 90 percent in the cold 

season). Sulfates are above 20 percent in the warm season. Crustal components in the 

warm season, sulfates in the cold season, and nitrates were not found. Crustal was 10 

percent of the cold season urban increment. Figures 2 and 3 show the “urban increment” 

to identify non-regional contribution of PM2.5 on high days for the Allentown, PA-NJ 

area. 

Warm Season (May-Sept)

Increments in ug/m3

Carbon - 6.5 ug/m3

79%

Nitrate - 0.0 ug/m3

0%

Sulfate - 1.7 ug/m3

21%

Crustal -0 ug/m3

0%

Figure 2. PM2.5 Compositional Analysis of Warm Season Urban Increment for Allentown, PA-NJ 

area. Total Urban Increment = 8.2 ug/m3

 

3
Cold Season (Jan-Apr, Oct-Dec)

Increments in ug/m3

Crustal - 0.1 ug/m3

10% Sulfate - 0 ug/m3

0%

Nitrate - 0 ug/m3

0%

Carbon - 0.9 

ug/m3

90%

Figure 3. PM2.5 Compositional Analysis of Cold Season Urban Increment for Allentown, PA-NJ 

area. Total Urban Increment = 1 ug/m3

 

Based on EPA's technical analysis described below, EPA proposes that Warren County, 

New Jersey, in its entirety, be designated attainment/ unclassifiable. EPA has taken the 

state’s request that Knowlton Township in Warren County be designated as 

“nonattainment” on the basis of air quality modeling analysis under consideration. 

However, current regulations for determining violations of the fine particle NAAQS2 and 

current policy for designating nonattainment areas for the fine particle NAAQS3

 require 

that violations of the PM2.5 standards be determined on the basis of complete, qualityassured ambient air quality monitoring data at a monitor in the area. These regulations 

and policy do not provide for PM2.5 violations to be determined through means other than 

ambient air quality monitoring. Thus, EPA finds that the information provided to date by 

the State does not adequately support a partial county nonattainment designation. EPA 

will consider any additional information provided by the State in making final decisions 

on the designations. 

 

2

 See the regulations on the revised standard at 40 CFR 50.13(c); 71 FR 61224, October 17, 2006. See also 

monitoring regulations at 40 CFR Part 58, as revised on 

October 17, 2006 (see 71 FR 61236); and procedures for using these data to determine whether a 

violation has occurred in 40 CFR Part 50 Appendix N, as revised on October 17, 2006 

(see 71 FR 61144).

3

 See “Area Designations for the 24-Hour Fine Particle National Ambient Air Quality Standard, “ signed by 

Robert J. Meyers, Acting Assistant Administrator, June 7, 2007; 

http://www.epa.gov/ttn/naaqs/pm/docs/june_2007_guidance_for_area_designations_for_2006_24-

hour_pm2.5.pdf 

4
Allentown, PA-NJ area State-Recommended 

Nonattainment Counties 

EPA-Proposed 

Nonattainment Counties 

New Jersey Warren County (Partial) - 

Knowlton Township 

None 

The following is a summary of the technical analysis, including 9-factor analysis, for the 

EPA Region 2 portion of the Allentown, PA-NJ area. 

EPA is proposing attainment/ unclassifiable for Warren, Sussex, and Hunterdon counties. 

These counties had low emissions, low Contributing Emission Scores (CES), low 

population, low commuting numbers, low growth, and low meteorological and 

geographical impact which indicates minimal contribution to violating monitors in the 

Allentown, PA-NJ area. These counties also do not have any violating ambient air 

quality monitors. Morris County has been recommended for inclusion in the Northern 

New Jersey-Long Island, NY-NJ-CT nonattainment area. Detailed information regarding 

the inclusion of Morris County into that area can be found in EPA’s Technical Analysis 

for the Northern New Jersey-Long Island, NY-NJ-CT nonattainment 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,” and “NOx”. “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. 

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 way for consideration of data for these 

factors. A summary of the CES is included in Attachment 2, and 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 Allentown, 

PA-NJ area. Counties are listed in descending order by CES. The counties that are 

5
currently designated nonattainment area for the 1997 PM2.5 NAAQS are shown in 

boldface. 

County State 

Recommended 

Non-attain 

ment? 

CES PM2.5 

emissions 

total 

(tpy)

PM2.5 

emissions 

carbon

(tpy) 

PM2.5 

emissions 

other 

(tpy)

SO2

(tpy) 

NOx

(tpy) 

Northampton, PA Yes 100 5,222 665 4,556 60,396 24,620 

Lehigh, PA Yes 35 1,328 501 828 3,749 11,503 

Berks, PA Yes-other 25 3,378 922 2,456 18,874 18,086 

Montgomery, PA Yes-other 23 2,597 1,118 1,477 5,411 23,306 

Bucks, PA Yes-other 19 2,022 876 1,146 3,951 16,792 

Warren, NJ Yes-Partial 12 1,105 588 517 563 5,088 

Monroe, PA No 12 1,153 590 563 1,022 5,245 

Hunterdon, NJ No 10 769 454 316 556 3,882 

Schuylkill, PA No 10 1,247 547 700 7,239 6,219 

Carbon, PA No 9 649 313 336 1,432 2,913 

Morris, NJ Yes-other 5 1,498 953 545 1,177 13,774 

Sussex, NJ No 3 1,270 744 526 669 2,726 

Pike, PA No 1 802 419 384 266 2,353 

Table 1. PM2.5 Related Emissions and Contributing Emissions Score

Generally, New Jersey Counties have lower emissions than the other potentially 

contributing counties. CES scores were generally low for the New Jersey counties, 

which is indicative of low impact on the violating monitors in the area. 

Hunterdon County, NJ has especially low emissions in comparison to the other counties 

in the area. Hunterdon, NJ emissions account for slightly over three percent of the total 

PM2.5 emissions, four percent of the carbon emissions, and about half of one percent of 

the total SO2 emissions for the area. The CES score of 10 was consistent with low 

contribution. 

Warren County, NJ also has relatively lower emissions than most of the other counties in 

the area. 2005 carbon emissions were 588 tons, which represents about six percent of the 

total emissions for the area under consideration. In comparison, other counties had much 

higher carbon emissions in the area, including Montgomery, PA (i.e. 1,118 tons), and 

Berks, PA (i.e. 922 tons). The CES score of 12 was consistent with lower contribution. 

Morris County, New Jersey also had relatively higher carbon emissions (i.e. 953 tons) 

than most of the other counties in the area. Total PM2.5 emissions were 1,498 tons, which 

was mid-range when compared to the other counties. However, the CES score was very 

low (5 on a scale of 100), and Morris County has been recommended for inclusion in the 

Northern New Jersey-Long Island, NY-NJ-CT area. Morris County has been included in 

this area for the current annual PM2.5 standard and EPA believes that it is appropriate to 

keep Morris County in the Northern New Jersey-Long Island, NY-NJ-CT nonattainment 

area. Detailed information regarding the inclusion of Morris County into the Northern 

New Jersey-Long Island, NY-NJ-CT nonattainment area can be found in EPA’s 

6
Technical Analysis for the New York-Northern New Jersey-Long Island, NY-NJ-CT 

area. 

Sussex County, NJ has very low SO2 emissions in comparison to the other counties (less 

than 1% of the total SO2 emissions). Carbon emissions were 744 tons, and total PM2.5

emissions were 1,270 tons, which was mid-range when compared to the other counties. 

However, the CES score was 3 on a scale of 100 indicating minimal contribution to the 

county with the violating monitor. 

In their December 2007 recommendation to EPA, New Jersey used 2002 emissions and 

projected 2009 emissions from the 2002 MANE-VU Modeling Inventory. New Jersey 

evaluated the same New Jersey Counties in their analysis (i.e. Warren, Hunterdon, 

Sussex, and Morris). New Jersey also showed relatively lower emissions than the other 

counties in the area. 

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 Allentown, PA-NJ 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 Allentown, PA-NJ area are shown in 

Table 2. 

County State Recommended Nonattainment? Design Values

2005-07

(μg/m3

) 

Northampton, PA Yes 37 

Lehigh, PA Yes No monitor 

Berks, PA Yes-other 40 

Montgomery, PA Yes-other No monitor 

Bucks, PA Yes-other 35 

Warren, NJ Partial 34 

Monroe, PA No No monitor 

Hunterdon, NJ No No monitor 

Schuylkill, PA No No monitor 

Carbon, PA No No monitor 

Morris, NJ Yes-other 32 

Sussex, NJ No No monitor 

Pike, PA No No monitor 

Table 2. Air Quality Data 

In EPA Region 2, there are no New Jersey counties in the Allentown, PA-NJ area that 

show a violation of the 24-hour PM2.5 standard as determined by air monitoring. The 

7
2005-2007 design values for Warren and Morris counties are 34 μg/m3

 and 32 μg/m3, 

respectively. The counties of Hunterdon, and Sussex, do not have monitors.

Northampton and Berks Counties in Pennsylvania, which are located in Region 3, violate 

the 24-hour PM2.5 standard. The proximity of the Northampton, PA and Warren County, 

NJ is presented in Figure 4. Figure 5 shows the results of New Jersey’s modeling 

analysis. Figures 6 and 7 show the similarity between the data collected from the 

monitors located in Northampton County, PA and Warren County, NJ. 

Figure 4. Map showing Freemansburg, PA and Phillipsburg, NJ. 

8
Figure 5. Map of the Allentown-Bethlehem-Easton PA-NJ area. The map insert shows modeling 

results provided by New Jersey, which the State identifies as information indicating a violation in 

Warren County. 

9
2004 PM2.5 Data

0

10

20

30

40

1 7 13 19 25 31 37 43 49 55 61 67 73 79 85 91 97 103

Common Sampling Days

ug/m 3

Warren (Phillipsburg) Northampton (Freemansburg)

Figure 6. Comparison of 2004 Phillipsburg and Freemansburg Monitoring data 

2005 PM2.5 Data

0

10

20

30

40

50

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

Common Sampling Days

ug/m3

Warren (Phillipsburg) Northampton (Freemansburg)

Figure 7. Comparison of 2005 Phillipsburg and Freemansburg Monitoring data 

10
Note: Eligible monitors for providing design value data generally include State and 

Local Air Monitoring Stations (SLAMS) at population-oriented locations with a FRM or 

FEM monitor. All data from Special Purpose Monitors (SPM) using an FRM, FEM, or 

Alternative Reference Method (ARM) which has operated for more than 24 months 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 3 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. 

Morris County ranks high in population and population density in comparison to other 

counties in the Allentown, PA-NJ Area. Morris County has been included in the New 

York City Metropolitan nonattainment area. 

Hunterdon and Sussex County rank low in population and population density in 

comparison to other counties in the area. Hunterdon County has less than half the 

population and population density of the violating county of Northampton, PA. Sussex 

County also has less than half the population density and approximately half (53%) the 

population of Northampton, PA. 

Warren County ranks low in terms of population and in population density in comparison 

to counties located near the violating monitor in Northampton. In comparison to the two 

counties that have been recommend as nonattainment for the Allentown, PA-NJ area, 

Warren County’s population and population density is below 50% that of Lehigh and 

Northampton. 

Population density and degree of urbanization for Hunterdon, Sussex, and Warren 

counties are low for the area of analysis. Population-based emissions did not play a role 

in designation. 

County State Recommended Nonattainment 2005 

Population 

2005 Population 

Density (pop/sq mi) 

Montgomery, 

PA Yes-other 774,666 1591 

Bucks, PA Yes-other 619,772 998 

11
Morris, NJ Yes-other 490,084 1019 

Berks, PA Yes-other 396,236 458 

Lehigh, PA Yes 330,168 948 

Northampton, PA Yes 287,334 762 

Monroe, PA No 162,415 264 

Sussex, NJ No 152,726 285 

Schuylkill, PA No 146,996 188 

Hunterdon, NJ No 130,042 297 

Warren, NJ Yes-Partial 110,317 305 

Carbon, PA No 61,876 160 

Pike, PA No 56,180 99 

The counties that are currently designated nonattainment for the 1997 PM2.5 NAAQS are shown in 

boldface. 

Table 3. Population 

Factor 4: Traffic and commuting patterns

This factor considers the number of commuters in each county who drive to another 

county within the Allentown-Bethlehem-Easton CBSA, the percent of total commuters in 

each county who commute to other counties within the Allentown, PA-NJ area, as well as 

the total Vehicle Miles Traveled (VMT) for each county in millions of miles (see Table 

4). A county with numerous commuters is generally an integral part of an urban area and 

could be an appropriate county for implementing mobile-source emission control 

strategies, thus warranting inclusion in the nonattainment area. 

County 

State 

Recommended 

Nonattainment? 

2005 VMT 

(million 

miles) 

Number 

Commuting 

to any 

violating 

counties 

Percent 

Commuting 

to any 

violating 

counties 

Number 

Commuting 

into 

statistical 

area 

Percent 

Commuting 

into 

statistical 

area 

Berks, PA Yes-other 3,320 147,990 83 7,250 4 

12
Lehigh, PA Yes 3,374 131,610 89 129,570 88 

Northampton, 

PA Yes 2,399 99,230 79 106,210 85 

Schuylkill, PA No 1,353 7,790 12 3,030 5 

Carbon, PA No 699 6,900 27 19,070 74 

Montgomery, 

PA Yes-other 7,527 6,660 2 2,480 1 

Monroe, PA No 1,556 5,140 8 7,060 11 

Bucks, PA Yes-other 5,250 3,980 1 3,870 1 

Warren, NJ Yes-Partial 1,342 2,410 5 23,440 47 

Hunterdon, NJ No 929 520 1 1,630 3 

Pike, PA No 584 200 1 360 2 

Morris, NJ Yes-other 5,398 130 0 1,760 1 

Sussex, NJ No 889 40 0 1,440 2 

The counties that are in the currently designated nonattainment for the 1997 PM2.5 NAAQS are shown 

in boldface. 

Table 4. Traffic and Commuting Patterns 

The listing of counties on Table 4 reflects a ranking based on the number of people 

commuting to other violating counties. 

The VMT for the residents of Warren County is low relative to other counties in the area. 

47% of the commuting from Warren County commute into the statistical area. The total 

number of Warren County commuters into the statistical area and violating counties is in 

the middle range of all the counties considered for contribution to the Allentown, PA-NJ 

area. Based on Factor 4, Warren County is a low traffic and commuting contributor to 

the Allentown, PA-NJ area. Warren County, NJ does not rank high with respect to this 

factor. 

For other counties in the Allentown, PA area, Morris, Hunterdon, and Sussex counties 

rank in the lower third for the number of commuters into the statistical area, and into the 

violating counties. Sussex and Hunterdon counties also have low VMT. Morris County, 

which is included as part of the New York City Metropolitan nonattainment area, has a 

high amount of VMT, but the low number of commuters into the Allentown-BethlehemEaston CBSA precludes the inclusion of Morris into the Allentown, PA nonattainment 

area. 

13
Projections from the Federal Highway Administration show that average annual daily 

truck traffic is projected to increase in the area through 2020 for two roads that run 

though Warren County (Interstate 78 and Interstate 80). Morris, Hunterdon, and Sussex 

counties are also projected to have increases in truck traffic. The projected increase for 

all of the counties considered was not significant enough to play a role in the designation 

of the counties Figure 8 shows projected 2020 annual average daily truck traffic. 

Figure 8. Estimated Average Annual Daily Truck Traffic in 2020

Note: The 2005 VMT data used for Table 4 and 5 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_mobile_nei_ve

rsion_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 looks at expected population for 2000-2005 and VMT from 1996-2005 in the 

Allentown, PA-NJ area, as well as patterns of population and VMT growth. A county 

14
with rapid population or VMT growth is generally an integral part of an urban area and 

could be an appropriate county for implementing mobile-source and other emissioncontrol strategies, thus warranting inclusion in the nonattainment area. 

Table 5 below shows population, population growth, VMT and VMT growth for counties 

that are included in the Allentown, PA-NJ area. Counties are listed in descending order 

based on VMT growth between 1996 and 2005. 

County 2005 Population 

Percent 

Population 

Change 

(2000-05) 

Vehicle Miles 

Traveled in 2005 

(millions 

annually) 

Percent VMT Growth 

(1996-2005) 

Montgomery, PA 774,666 3 7,527 73 

Morris, NJ 490,084 4 5,398 56 

Bucks, PA 619,772 3 5,250 49 

Lehigh, PA 330,168 6 3,374 34 

Northampton, PA 287,334 7 2,399 21 

Monroe, PA 162,415 16 1,556 19 

Berks, PA 396,236 6 3,320 11 

Warren, NJ 110,317 7 1,342 2 

Carbon, PA 61,876 5 699 0 

Schuylkill, PA 146,996 -2 1,353 -1 

Pike, PA 56,180 20 584 -8 

Sussex, NJ 152,726 6 889 -22 

Hunterdon, NJ 130,042 6 929 -42 

The counties that are currently designated nonattainment in Table 5 for the 1997 PM2.5 NAAQS are 

shown in boldface. 

Table 5. Population, VMT Growth, and Percent VMT Growth Change 

Warren County experienced 7% growth from 2000-2005. The growth rate for Warren 

County is average in comparison to other counties in the area and equivalent to 

Northampton and Lehigh. On a per person basis, the growth in the number of people 

residing in Warren County is low. Only Carbon and Schuylkill had a lower percentage of 

population change. Montgomery, Berks, and Monroe County had the largest growth in 

population from 2000-2005. 

VMT by the residents of Warren County are low in comparison with other counties in the 

area. The growth in VMT from 1996-2005 for Warren County is low in comparison with 

Northampton and Lehigh (21% and 34%, respectively). Hunterdon and Sussex counties 

had low population and negative VMT growth. The counties of Morris, Montgomery, and 

Bucks, had the highest percentage of growth from 1996-2005. Morris County is being 

included in the New York City Metropolitan nonattainment area. . 

Factor 6: Meteorology (weather/transport patterns)

For this factor, EPA considered the most representative National Weather Service wind 

direction and speed data throughout the year, 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. 

15
 

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 9 identifies 24-hour PM2.5 values by color; days exceeding 35 

ug/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. 

For this factor, EPA also considered each County’s CES, which includes an analysis of 

trajectories of air masses for high PM2.5 days. 

Figure 9. Pollution Rose for Northampton County, PA 

Table 6 shows the average prevailing surface wind directions for high PM2.5 days by 

quadrant for the proposed nonattaining counties in the Allentown, PA-NJ area, as well as 

Warren County, NJ. The data shows that 24-hour PM2.5 concentrations are influenced by 

emissions in any direction at various times and the data also suggest that emissions in 

some directions relative to the violation are more likely to contribute than emissions in 

other directions.

16
County Prevailing Wind Direction (%) 

NW SW SE NE 

Northhampton 

County, PA 

4% 74% 3% 19% 

Lehigh County, 

PA 

11% 78% 0% 11% 

Warren County, 

NJ 

0% 70% 10% 20% 

Table 6. Prevailing Wind Directions for High PM2.5 Days.

EPA’s analysis of meteorology shows that PM2.5 emissions during high PM2.5 days in 

2004-2006 primarily originated and/or passed through locations from a southwesterly 

direction. This is also evident upon examination of the pollution rose for Northampton 

County (see Figure 9). Since the winds are seldom from the Northeast, the emissions 

from Morris, Hunterdon, Sussex and Warren counties would have little or no impact on 

the PA counties. 

Based on our analysis, this factor does not support including Morris, Hunterdon, Sussex 

and Warren County in the Allentown, PA-NJ nonattainment area. 

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 looks at physical features of the land that might have 

an effect on the air shed and, therefore, on the distribution of PM2.5 over the Allentown, 

PA-NJ area. 

The Allentown, PA-NJ area does not have any geographical or topographical barriers 

significantly limiting air pollution transport within its airshed. The Delaware River 

separates Hunterdon and Warren counties from the other counties in the Allentown, PANJ area, however this is not a significant barrier that would influence the airshed. Morris 

and Sussex counties do not have any geographical or topographical barriers that could 

significantly limit air pollution transport. This factor did not play a significant role in the 

decision-making process 

. 

Factor 8: Jurisdictional boundaries (e.g., existing PM and ozone areas) 

In evaluating the jurisdictional boundary factor, consideration should be given to existing 

boundaries and organizations that may facilitate air quality planning and the 

implementation of control measures to attain the standard. Areas designated as 

17
nonattainment (e.g for PM2.5 or 8-hour ozone standard) represent important boundaries 

for state air quality planning. 

The major jurisdictional boundary in the Allentown, PA-NJ nonattainment area is the 

State line between Pennsylvania and New Jersey. 

While all of New Jersey has been previously designated nonattainment for 8-hour ozone, 

the New Jersey counties in the Allentown, PA-NJ area are not in the same 8-hour ozone 

nonattainment area as the counties from Pennsylvania. . 

The Allentown, PA-NJ area is also not an existing nonattainment area for the 1997 PM2.5

NAAQS. In EPA’s June 2007 Guidance for Area Designations for the 24-hr PM2.5 

NAAQS, EPA had indicated that we expected that the boundaries for the existing 1997 

PM2.5 nonattainment areas would have been appropriate for the boundaries of the new 

nonattainment areas for the 2006 PM2.5 NAAQS. 

Although we considered this information regarding jurisdictional boundaries, the 

jurisdictional boundaries factor did not influence heavily in our decision-making for the 

area. 

Factor 9: Level of control of emission sources 

This factor considers emission controls currently implemented in the Allentown, PA-NJ

area. This factor analysis generally considered the emissions controls currently in place. 

The emission estimates on Table 1 (under Factor 1) include any control strategies 

implemented by the States in the Allentown, PA-NJ area before 2005 that may influence 

emissions of any component of PM2.5 emissions (i.e., total carbon, SO2, NOx, and crustal 

PM2.5). Since we believe that the emissions listed in Table 1 have not changed 

significantly since 2005, this factor does not influence heavily in our decision-making. 

In considering county-level emissions, EPA considered 2005 emissions data from the 

National Emissions Inventory. EPA recognizes that certain power plants or large sources 

of emissions in this potential nonattainment area may have installed emission controls or 

otherwise significantly reduced emissions since 2005 and that this information may not 

be reflected in this analysis. EPA will consider additional information on emission 

controls in making final designation decisions. In cases where specific plants already 

have installed emission controls or plan to install such controls in the near future, EPA 

requests additional information on: 

- the plant name, city, county, and township/tax district 

- identification of emission units at the plant, fuel use, and megawatt capacity 

- identification of emission units on which controls will be installed, and units on which 

controls will not be installed 

18
- identification of the type of emission control that has been or will be installed on each 

unit, the date on which the control device became / will become operational, and the 

emission reduction efficiency of the control device 

- the estimated pollutant emissions for each unit before and after implementation of 

emission controls 

- whether the requirement to operate the emission control device will be federally 

enforceable by December 2008, and the instrument by which federal enforceability will 

be ensured (e.g. through source-specific SIP revision, operating permit requirement, 

consent decree) 

Other Relevant Information 

The New Jersey Department of Environmental Protection (DEP) has performed an 

analysis using the CALPUFF air quality model, which indicates modeled violations in the 

Knowlton Township area of Warren County. The DEP analysis concluded that the 

Reliant power plant in Northampton County, PA is the cause of this modeled violation. 

New Jersey seeks to have only the Knowlton Township area of Warren County 

designated as nonattainment. 

While the analysis indicates an impact in the Knowlton Township area, EPA has 

determined that there is insufficient information to conclude that the air quality violations 

of the fine particle NAAQS has occurred.. Current regulations and policy require that 

violations of the PM2.5 standards be determined on the basis of complete, quality-assured 

ambient air quality monitoring data at a monitor in the area. The regulations and policy 

do not provide for PM2.5 violations to be determined through means other than ambient 

air quality monitoring. Currently there is no violating monitor present in Warren County. 

EPA recognizes that an air quality monitor located in the area of impact as determined by 

air quality modeling could show a violation of the 24-hour PM2.5 standard. For this 

reason, EPA strongly advises that New Jersey place an air quality monitor in the vicinity 

of Knowlton Township, which is downwind of the Reliant power plant in Northampton 

County, to support the state’s determination that Warren County (or portions thereof) is 

violating the 24-hour PM2.5 standard. 

 EPA is recommending that the entire county of Warren be designated attainment/ 

unclassifiable for the 24-hour PM2.5 standard 

19
1

ENCLOSURE 

The Commonwealth of Pennsylvania’s Response to the U.S. Environmental 

Protection Agency’s Proposed PM2.5 Designations 

Executive Summary.

The Governor of the Commonwealth of Pennsylvania (Commonwealth or Pennsylvania), 

Edward G. Rendell, received notification via letter dated June 29, 2004 of the U.S. 

Environmental Protection Agency’s (EPA’s) modifications to Pennsylvania’s 

recommendations for particulate matter (PM2.5) nonattainment area boundaries. EPA’s 

proposed modifications add Lawrence, Butler, Armstrong and Greene counties to the 

Pittsburgh nonattainment area and add Mercer County to the Youngstown nonattainment 

area. The proposed modifications add three attainment counties (Indiana, Armstrong and 

Greene) to adjacent nonattainment areas solely because of the emissions from power 

plants located in Indiana, Armstrong and Greene counties. EPA’s modifications add 

Lebanon, Bucks and Montgomery counties to nonattainment areas, based primarily on 

Metropolitan Area definitions, despite the fact that the data strongly supports a 

designation of attainment for these counties.” (See Figure 1) 

The Pennsylvania Department of Environmental Protection (DEP or Department) has 

conducted a comprehensive evaluation of EPA’s proposed recommendations. Based on 

(1) further review and analysis of available data by the Department and the Allegheny 

County Health Department, (2) public input, and (3) EPA criteria regarding the 

designation process, Pennsylvania finds it necessary to amend our recommendations for 

the Pittsburgh area. The analysis shows that unique, local PM2.5 problems exist in the 

vicinities of the Liberty Borough, Clairton and North Braddock monitors. Pennsylvania 

recommends creation of two additional nonattainment areas within the Pittsburgh 

nonattainment area to address the unique needs of these two local areas. 

Liberty Borough, Clairton and North Braddock monitors. Allegheny County Health 

Department staff and Pennsylvania Bureau of Air Quality staff have been investigating 

PM2.5 concentrations in the vicinities of the Liberty Borough, Clairton and North 

Braddock monitors to assess evidence of localized air quality issues that are not 

representative of the conditions present in the rest of the Pittsburgh area. These two areas 

have had a history of PM10 nonattainment and are clearly impacted by nearby industrial 

sources that are already extensively controlled. Therefore, bringing this area into 

attainment will take longer than the rest of the Pittsburgh area. These factors necessitate 

creation of two additional nonattainment areas within the Pittsburgh nonattainment area. 

The attainment status of the entire EPA proposed eight-county Pittsburgh area must not 

be tied to unique, local problems that will require development of highly specialized local 

solutions in addition to any regional controls that are applied throughout the area. 

Additional analysis of the monitoring and meteorology data to support two partial county 

nonattainment areas for these communities has been conducted. The details of the 

analysis and recommendations for the boundaries of the two areas can be found on pages 

15 - 25 of this document. 
2

In addition to the necessary amendment to Pennsylvania’s recommendations for the 

Pittsburgh area, Pennsylvania has three major areas of concerns with EPA’s proposed 

modifications. EPA’s proposed modifications: 

• Append Mercer, Lawrence and Butler Counties to adjacent nonattainment areas 

• Designate counties as nonattainment solely due to the presence of a power plant 

• Include Lebanon, Bucks and Montgomery Counties in nonattainment areas, 

despite data that strongly supports a designation of attainment. 

Mercer, Lawrence, and Butler Counties. EPA’s proposed designations would include 

Mercer County as part of the Youngstown nonattainment area and Butler and Lawrence 

Counties as part of the Pittsburgh nonattainment area. Mercer County is monitoring 

attainment, has low population density and low vehicle miles traveled (VMT). In 

addition, Mercer County has low emissions which are also predominantly downwind of 

the nonattaining monitors and would contribute very little to nonattainment in the 

Youngstown area. More information about DEP’s analysis of Mercer County can be 

found on pages 27 - 28 of this document. 

Butler County has low emissions, low population density and low VMT. Butler County 

scores very low in EPA’s own weighted emissions analysis. There is no reason to 

conclude that this county should be nonattainment. DEP strongly believes that it is 

inappropriate to designate Butler County as nonattainment of the PM2.5 standard. 

Lawrence County has historically not been a part of the Pittsburgh planning area for 

ozone. Lawrence County has relatively low emissions. More information about DEP’s 

analysis of Butler and Lawrence Counties can be found on page 26 - 27 of this document. 

Power Plant Counties. EPA included Indiana, Armstrong and Greene Counties as 

nonattainment for PM2.5 solely because of the emissions from coal-fired power plants that 

are located in these counties. Pennsylvania strongly opposes this approach. It has been 

our position throughout this process that emissions from large point sources, including 

power plants must be addressed by national or regional legislation or regulation. More 

detailed discussion about Pennsylvania’s concerns about the proposed nonattainment 

designation of these counties can be found on page 7 for Indiana County, page 26 for 

Armstrong County and on page 25 for Greene County. 

Lebanon, Bucks and Montgomery Counties. Pennsylvania does not believe Lebanon 

County should be included in the Harrisburg nonattainment area. Lebanon County has 

low emissions and will have little or no effect on design values in the nonattainment area 

since Lebanon County is generally downwind of Cumberland and Dauphin counties. A 

more detailed discussion about Pennsylvania’s recommendation of Lebanon County as 

attainment can be found on pages 5 - 6. 

The Pennsylvania DEP disagrees with EPA’s recommendation to expand the Philadelphia 

nonattainment area to include Montgomery and Bucks Counties. Montgomery and Bucks 

Counties are monitoring attainment of the PM2.5 standard. In addition, it appears that 
3

EPA did not take into account the level of controls in the five-county Philadelphia region. 

Strict emission control programs have reduced nitrogen oxide (NOx) and volatile organic 

compound (VOC) emissions by 35% when the region’s population has increased by 

nearly half a million people. Our analysis indicates that the Philadelphia region’s PM2.5

nonattainment problem is more local in scope and expanding the nonattainment area to 

include Bucks and Montgomery Counties will not help the region attain the annual PM2.5

standard. For a more detailed discussion, see pages 7 - 14. 

Figure 2 provides annual wind roses for these areas demonstrating the downwind location 

of these counties to the core urban areas. Figure 3 shows the location and name of 

monitors throughout Pennsylvania and adjoining states. Figure 4 shows the design values 

for these monitors based on monitored data from 2001, 2002 and 2003. 
4

Background.

In February 2004, Pennsylvania submitted recommendations to the EPA to designate 

attainment and nonattainment areas for the fine particulate matter (PM2.5) national 

ambient air quality standard. At that time, Pennsylvania recommended 16 counties for 

nonattainment based on air quality monitoring data and other available information, 

including emissions, meteorology and demographics. Those counties included 

Philadelphia, Delaware, Chester, Bucks, Montgomery, Berks, Lancaster, York, Dauphin, 

Cumberland, Lebanon, Cambria, Westmoreland, Washington, Allegheny and Beaver. In 

June 2004, Pennsylvania revised the recommendations to exclude Bucks, Montgomery 

and Lebanon from that list based on further analysis and EPA’s recently established 

“weighted emissions scoring” guidance and data concerning the designation process. 

As required by the federal Clean Air Act, EPA notified Pennsylvania, in a letter dated 

June 29, 2004, of its intention to modify Pennsylvania’s recommendations for some 

counties. While the Clean Air Act requires that states be provided a 120-day opportunity 

to demonstrate why any proposed modification is inappropriate, EPA has requested state 

comments by September 1, 2004, effectively giving Pennsylvania only half of the 120 

days provided in the Act. Pennsylvania reserves the right to submit additional 

information through out the entire 120-day period required by law prior to promulgation 

by EPA. 

The June 29th letter to Governor Rendell identified 22 counties as proposed PM2.5

nonattainment in Pennsylvania. In addition to the 13 counties identified in 

Pennsylvania’s revised recommendations, EPA proposed the addition of Lebanon, 

Indiana, Montgomery, Bucks, Butler, Armstrong, Greene, Lawrence and Mercer as 

nonattainment areas. 

Pennsylvania’s recommendations were developed with consideration given to EPA 

guidance. The first guidance memo (dated April 1, 2003) from EPA Assistant 

Administrator Jeffrey R. Holmstead outlined EPA’s intention to apply a presumption that 

the boundaries for urban nonattainment areas should be based on Metropolitan Area 

boundaries, as defined by the Office of Management and Budget (OMB) and published 

on June 30, 1999. The guidance memo listed factors that EPA will consider if states 

request nonattainment area boundaries that are different from OMB’s metropolitan area 

definitions. These factors are: 

• Emissions in areas potentially included versus excluded from the nonattainment 

area 

• Air quality in potentially included versus excluded areas 

• Population density and degree of urbanization including commercial development 

in included versus excluded areas 

• Traffic and commuting patterns 

• Expected growth (including extent, pattern and rate of growth) 

• Meteorology (weather/transport patterns) 

• Geography/topography (mountain ranges or other air basin boundaries) 
5

• Jurisdictional boundaries (e.g., counties, air districts, Reservations, etc.) 

• Level of control of emission sources 

EPA issued additional guidance on February 12, 2004 on the PM2.5 designation process, 

in the form of a memo from Lydia N. Wegman. The additional guidance indicated that 

OMB’s revised Metropolitan Area boundaries, issued June 10, 2003, should also be 

considered in States’ recommendations and in EPA’s review and determination of PM2.5 

designation boundaries. 

Pennsylvania remains convinced that the 13 counties identified by both EPA and 

Pennsylvania as nonattainment are the only counties in Pennsylvania that should be 

designated nonattainment with regard to the PM2.5 standard. (emphasis added) 

Pennsylvania’s analysis and recommendations were completed in accordance with EPAissued guidance. EPA’s newly developed “weighted emissions” scoring process is 

arbitrary and appears to expand nonattainment areas to include counties monitoring 

attainment solely because of the relative emission levels without any demonstration of air 

quality impact. This process was never published for review and comment. It has long 

been Pennsylvania’s position that it is imperative that emissions from large point sources, 

including power plants, be addressed through a consistent national or regional control 

program. EPA’s recently proposed Clean Air Interstate Rule (CAIR) would be an 

appropriate mechanism for addressing these emissions provided more stringent emission 

caps and timely compliance schedules are promulgated. 

The following discussion provides relevant analysis and our comments on EPA’s 

intended designations for each area: 

HARRISBURG AREA

In the June 29, 2004 “120-day letter”, EPA gave notice of its intention to expand the 

Harrisburg nonattainment area to include Cumberland, Dauphin and Lebanon counties. 

Pennsylvania recommends that only Cumberland and Dauphin counties be included in 

the Harrisburg nonattainment area. Table 1 summarizes 2001-03 annual PM2.5 

concentrations in the Harrisburg region. 

Table 1. 

Harrisburg Region 2001-03 PM2.5 Annual Design Value 

Site County 2001-03 design Value 

(μg/m3)

Annual Standard 

(μg/m3)

Carlisle Cumberland 15.1** 15.0 

Harrisburg Dauphin 15.7 15.0 

Little Buffalo SP Perry 13.0 15.0 

**Combined data from two monitors 
6

There is a discrepancy between Cumberland County’s design value cited in EPA’s June 

29, 2004 letter and what’s listed in Table 1. EPA listed Cumberland County’s design 

value as 17.6 μg/m3

, but noted that the data for the county was incomplete. The Carlisle 

monitor was moved at the end of the first quarter of 2001. It appears EPA used the old 

monitoring site’s 1st quarter 2001 PM2.5 concentration as the county’s annual design 

value. Pennsylvania combined data from both sites to calculate the 2001-03 annual PM2.5

design value for Cumberland County. Both sites are within 3 miles of each other (see 

Appendix II, Figure 5). 

EPA’s Analysis in Support of an Expanded Nonattainment Area 

In its June 29, 2004 letter to Pennsylvania, EPA outlined its intentions for the Harrisburg 

nonattainment area. EPA cited lack of emissions and the county’s low annual design 

value as supporting factors for this decision. Lebanon County, however, was added to 

the nonattainment area; Pennsylvania had requested that only Dauphin and Cumberland 

counties be included in the Harrisburg nonattainment area. EPA cited Lebanon County’s 

location adjacent to several other nonattainment counties as supporting evidence for its 

position. Including Lebanon County “...completes a contiguous nonattainment 

boundary.” 

Pennsylvania’s Comments Regarding EPA’s Analysis 

Pennsylvania concurs with EPA’s proposed designation of attainment for Perry County. 

Pennsylvania opposes the inclusion of Lebanon County in the Harrisburg nonattainment 

area. Emissions from Lebanon County are roughly two thirds (2/3) of emissions from 

either Cumberland or Dauphin counties. Any emission controls imposed on Lebanon 

County will have little or no effect on design values in the nonattainment area since 

Lebanon County is generally downwind of Cumberland and Dauphin counties. The 

proposed inclusion of Lebanon County solely to establish a contiguous nonattainment 

area seems more of an aesthetic exercise rather than assisting the nonattainment area to 

attain the annual PM2.5 standard. Figure 4 shows that while the cities of Harrisburg, 

Lancaster and Reading show nonattainment, surrounding counties, particularly to the 

north such as most of Lebanon County, show attainment. 

JOHNSTOWN AREA

In the June 29, 2004 letter, EPA gave notice of its intention to expand the Johnstown 

nonattainment area to include Cambria and Indiana. Pennsylvania recommends that the 

nonattainment area include only Cambria. 

There is a discrepancy in the Johnstown PM2.5 annual design value. EPA’s analysis 

indicates the 2001-03-design value is 15.8 μg/m3

. Our analysis indicates Johnstown’s 

design value is slightly lower, 15.6 μg/m3

. 
7

Pennsylvania’s Comments Regarding EPA’s Analysis 

Pennsylvania remains convinced that Indiana County should be designated attainment for 

the PM2.5 standard. Indiana is a rural, non-industrial county that is not associated with 

any Metropolitan Statistical Area (MSA). Indiana has relatively high emissions, but 

these are mainly attributable to the county’s three power stations – accounting for 99.4% 

of the sulfur dioxide (SO2) and 91.5% of the nitrogen oxide (NOx) emissions. These are 

Seward Station, Conemaugh Station and Homer City Station. The Seward Station was 

recently shut down and replaced with modern well-controlled fluidized bed units, 

representing state of the art controls. The Conemaugh Station is equipped with SO2 

scrubbers and electrostatic precipitators (ESPs) on both units. The Homer City Station 

has one of its three units equipped with SO2 scrubbers and all three units are equipped 

with selective catalytic reducers (SCR), low NOx burners and ESPs. The remainder of 

emissions from Indiana would have a negligible impact on either the nonattainment area. 

Subjecting the entire county to nonattainment status due to speculation that these sources 

for which additional controls will be required under the Clean Air Act regional haze rule 

and proposed CAIR is inappropriate. 

LANCASTER AREA

Pennsylvania concurs with EPA’s proposed nonattainment designation for Lancaster 

County. 

NEW YORK AREA

Pennsylvania concurs with EPA’s proposed designation of attainment for Pike County. 

PHILADELPHIA AREA

In the June 29, 2004 letter to Pennsylvania, EPA gave notice of its intention to expand the 

Philadelphia nonattainment area to include five counties: Bucks, Chester, Delaware, 

Montgomery and Philadelphia. Pennsylvania’s proposed Philadelphia PM2.5 

nonattainment area did not include Bucks or Montgomery counties (June 1, 2004 Revised 

PM2.5 Designation Recommendations). Both of these counties have 2001-2003 design 

values below the annual PM2.5 standard (15.0 μg/m3

). Table 2 lists the annual design 

values for the counties in Pennsylvania included in EPA’s proposed Philadelphia 

nonattainment area. 

The five-county Philadelphia region’s 2001-03 PM2.5 design value is 15.5 μg/m3

, slightly 

above the annual standard of 15.0 μg/m3

. Both Bucks and Montgomery counties have 

design values less than the annual standard. Additionally, these counties are thought to 

be generally downwind and/or not significantly contributing to monitors exceeding the 

annual standard. 
8

Table 2. 

2001-03 PM2.5 Design Values in the Five-County Philadelphia Region 

Site County 2001-03 design Value 

(μg/m3)

Annual Standard (μg/m3)

Bristol Bucks 14.4 15.0 

New Garden Chester 15.2** 15.0 

Chester Delaware 15.5 15.0 

Norristown Montgomery 14.3 15.0 

AMS Lab Philadelphia 15.2 15.0 

Belmont Philadelphia 14.3 15.0 

N/E Airport Philadelphia 13.8 15.0 

Broad Street Philadelphia “Middle-scale” monitor Compare to 24-hr standard 

Elmwood Philadelphia 14.9 15.0 

MLK New Castle, DE 16.2 15.0 

Camden Camden, NJ 14.6 15.0 

Gibbstown Gloucester, NJ 13.8 15.0 

From EPA letters to Delaware and New Jersey, ** Incomplete data set (2002-03) 

EPA’s Analysis in Support of an Expanded Nonattainment Area 

Technical justifications for expanding the Philadelphia PM2.5 nonattainment area were 

included in Enclosure B of EPA’s June 29, 2004 letter sent to Pennsylvania. EPA used 

nine criteria to determine which counties should be included in the Philadelphia 

nonattainment area. These criteria included emissions, air quality, population, traffic and 

commuting patterns, expected growth, meteorology, geography/topography, jurisdictional 

boundaries, and level of emission controls. 

EPA placed a high emphasis on weighted countywide emissions in its supporting 

document. EPA concluded its weighted emissions analysis showed Montgomery County 

and Bucks County significantly contributed to the region’s nonattainment problem. 

Additional analysis factors including population density, growth and commuting, were 

also cited in support for expanding the Philadelphia nonattainment area to include Bucks 

and Montgomery counties. 

Pennsylvania’s Comments Regarding EPA’s Analysis 

Philadelphia Annual PM2.5 Design Value: PM2.5 design values listed in EPA’s June 29, 

2004 designation letter are different than those complied by Pennsylvania and listed in 

Table 2. The five-county Philadelphia region’s design value is less than the value listed 

in EPA’s designation letter (16.4 μg/m3

). Less than half of the monitors in the fivecounty Philadelphia region exceed the annual PM2.5 standard. Expanding the 

nonattainment area would place counties measuring attainment into a nonattainment area. 
9

EPA’s Weighted Emissions Analysis: EPA’s use of weighted emission scores is 

problematic. This recently developed method cannot gauge how emissions are affecting 

a particular monitor’s design value. EPA’s method does not differentiate between 

different emission sources. A modeling analysis would be more helpful in determining if 

emissions from a particular county or a particular source type are significantly 

contributing to a monitor’s design value. 

EPA’s Sector Wind Frequency/Weighted Emissions Analysis: EPA’s attempt to use 

sector wind frequency and distance to the design monitor to determine emission transport 

is over simplified. The methodology uses 10 years of wind direction data to gauge were 

emissions may be transported. This method does not take into account other 

meteorological factors such as wind speed and atmospheric stability, which influence 

atmospheric dispersion. This method also ignores source characteristics that affect 

emission dispersion such as release height, plume temperature, plume velocity and does 

not account for chemical transformation processes. The analysis does not make a 

determination if the meteorological data used in the analysis is representative over the 

entire nonattainment area in accordance with Section 3 of EPA’s Meteorological 

Monitoring Guidance for Regulatory Modeling Applications (EPA-454/R-99-005). 

Distance to the design monitor may be incorrect since there is a discrepancy between 

EPA’s regional design value and what is listed in Table 1. 

EPA’s VMT Analysis: EPA considered VMT in its analysis but did not establish a clear 

relationship between VMT and monitored PM2.5 design values. VMT in the Philadelphia 

region is much higher than any other region in Pennsylvania yet its design value is only 

slightly above the annual PM2.5 standard. Furthermore, monitors in Bucks and 

Montgomery counties are located near major highways yet both monitors’ 2001-03 PM2.5

design values are less than the annual standard. If a definitive link exists between VMT 

and PM2.5 design values, one would expect higher values for monitors in the Philadelphia 

region than portions of central and western Pennsylvania. 

Table 3 summarizes VMT-PM2.5 correlation coefficients for all Pennsylvania counties. 

VMT and design monitor concentrations are weakly correlated with one another. If an 

average value is substituted for a county’s design value (counties with multiple 

monitoring sites) there is no VMT-PM2.5 correlation. 

Table 3. 

VMT-PM2.5 Correlation Coefficients for the Commonwealth of Pennsylvania 

 2001-03 Annual PM2.5 

Design Value * 

2001-03 Average PM2.5 

Design Value ** 

VMT 0.6557 0.3119 

* County Design Value (Max) 

** Average Design Value for counties with multiple monitors 
10

Stringent Emission Control Programs/Population Growth/Density: EPA’s analysis 

failed to account for stringent emission control programs implemented in the five-county 

Philadelphia region. Air contamination sources in Southeast Pennsylvania and most of 

the metropolitan regions along the I-95 corridor must comply with some of the most 

stringent emission control requirements in the nation. These controls were enacted to 

bring the Ozone Transport Region (OTR) into attainment of the one-hour ozone standard. 

Controls on NOx and VOC-emitting sources have undoubtedly helped reduce PM2.5

concentrations. The Department estimates NOx and VOC emissions will be reduced by 

35% between 1990 and 2005 in the five-county Philadelphia region. These emission 

reductions have occurred even though the region’s population has increased by 10.4% 

(half a million people) between 1980 and 2000. 

Table 4 summarizes population density-PM2.5 correlation coefficients for all 

Pennsylvania monitors. The results show there is no correlation between a county’s 

population density and it’s design value. 

Table 4. 

Population Density-PM2.5 Correlation Coefficients 

 for the Commonwealth of Pennsylvania 

 2001-03 Annual PM2.5 

Design Value * 

2001-03 Average PM2.5 

Design Value ** 

Population Density 0.2373 0.0860 

* County Design Value (Max) 

** Average Design Value for counties with multiple monitors 

Design Value Contribution Analysis 

Overview 

The Department has completed a design value contribution analysis for all of the PM2.5

monitors in the five-county Philadelphia region. Our analysis attempts to determine a 

monitor sample’s contribution to its annual PM2.5 design value. Samples are grouped into 

different PM2.5 concentration ranges. An analysis of each range’s contribution can then 

be examined to determine which samples are contributing to the monitor’s design value. 

Sample dates can then be further analyzed to determine if there are specific 

meteorological conditions or sources that are adversely affecting the monitor’s design 

value. Results from our design value analysis for southeast Pennsylvania are summarized 

in Table 5. 

Our design value contribution analysis indicates the two monitors in the five-county 

Philadelphia region that exceeded the annual standard, Chester and PHL-Lab, have 

relatively few “clean” days (0-7.5 μg/m3). Their design value contributions from this 
11

range are less than the statewide average and less than other monitors in the Philadelphia 

region. Graph 1 confirms Chester has fewer “clean” days, PM2.5 concentrations in the 0 

to 7.5 μg/m3

 range. 

Table 5. 

Southeast Pennsylvania 

PM-2.5 Annual Design Value Contribution Analysis 

Add “Sum” to 15.0 to get monitor’s annual design value. 

Additional analyses were done to try and determine what was contributing to the lack of 

“clean” days at Chester. To do this we identified days when Chester’s PM2.5

concentrations were relatively high but regional monitoring concentrations were low. 

Between 2001 and 2003 we identified 72 days where Chester’s PM2.5 concentrations 

were 25% or greater than the regional average. The most extreme events were examined 

further to determine why Chester’s concentrations were high when regional 

concentrations were low. 

Site Name 0-7.5 7.5-15 15-22.5 22.5-30 30-37.5 37.5-45 45-52.5 52.5-60 60-67.5 67.5-75 Sum

Bristol -2.1945 -1.6299 0.7112 0.9525 0.8442 0.3879 0.2026 0.1363 0.0000 0.0000 -0.59

Chester -1.4321 -1.6780 0.8684 1.0791 0.8254 0.4275 0.0894 0.1239 0.1470 0.0000 0.45

Norristown -2.2976 -1.7091 0.6782 0.9489 0.8432 0.1636 0.3095 0.1467 0.1775 0.0000 -0.74

PHL-Belmont -2.1229 -1.6089 0.8339 0.9816 0.6281 0.2920 0.1906 0.1157 0.0000 0.0000 -0.69

PHL-Elmwood -1.8026 -1.6580 0.8068 0.9680 0.8544 0.3010 0.2685 0.1737 0.0000 0.0000 -0.09

PHL-LAB -1.7461 -1.6521 0.7268 1.1130 0.9363 0.5302 0.2413 0.0890 0.0000 0.0000 0.24

PHL-Northeast Airport -2.4223 -1.6391 0.6829 0.8288 0.7105 0.3262 0.1097 0.2540 0.0000 0.0000 -1.15

New Garden (incomplete) -1.9109 -1.4315 0.7571 0.9206 1.0716 0.3139 0.0000 0.1918 0.0000 0.2421 0.15

Five-County Phila Avg -1.9911 -1.6258 0.7582 0.9741 0.8392 0.3428 0.1765 0.1539 0.0406 0.0303 -0.30

State Average -1.8539 -1.6112 0.7704 0.9833 0.7858 0.4223 0.2478 0.2103 0.0464 0.0527 0.05
12

Graph 1. 

Analysis of Speciated Data 

Speciated data for Chester and New Garden, a monitoring site ~21 miles west of Chester, 

were examined to determine if there were any significant differences on days when 

regional concentrations were low but Chester’s were high. A total of eleven (11) days 

were examined. Data was missing for most of the more extreme events. Table 6 lists 

standard deviations, correlation coefficients and correlations of divergence for these 

eleven days. These analyses indicate major differences in sulfate and crustal components 

between the two sites. 

Table 6. 

Statistical Analysis Chester/New Garden Speciated Data

PM-2.5 Category Breakdown

2001-2003: SE Pennsylvania

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

30.0%

35.0%

40.0%

45.0%

0-7.5

7.5-15

15-22.5

22.5-3030-37.537.5-45

45-52.552.5-6060-67.567.5-75

Bristol

Chester

Norristown

Nitrate Sulfate Ammonium Organic Carbon Elemental Carbon Crustal Other

Standard Deviation 1.2748 1.6022 0.7094 1.4553 0.3444 0.9071 2.7151

Correlation Coefficient 0.9725 -0.3467 0.8875 0.8247 0.6032 0.4838 0.1228

Coefficients of Divergence 0.0684 0.5048 0.3261 0.1237 0.2325 1.2103 1.4793
13

Criteria Pollutant/Meteorological Data Analysis 

Twenty-four hour averaged wind direction, wind speed, PM10 and sulfur dioxide 

concentrations for Chester, Norristown and Bristol were compared for nineteen days 

when PM2.5 concentrations at Chester were significantly higher than regional averages. 

On a majority of these days, sixteen, Chester’s surface winds had strong easterly 

components. Chester’s PM10 and sulfur dioxide levels were also significantly higher than 

Norristown and Bristol on these days. These values are summarized in Table 7. 

Quarterly PM2.5 Concentration Analysis 

Regional 2001-03 annual design values were influenced by unusually high PM2.5

concentrations during the first quarter of 2001 (Table 8). Quarterly averages were well 

above normal across the Commonwealth. The cause of this anomaly is not known but is 

probably not due to sources solely within the five-county Philadelphia region. 

Table 7. 

Nineteen-Day Summary Chester/Bristol/Norristown 

Date Chester Bristol Norristown Chester Bristol Norristown Chester Bristol Norristown Chester Bristol Norristown

9/12/03 53 22 18 10 4 0 81 45 104 8.5 7.3 4.4

12/14/03 58 7 5 8 11 1 119 102 107 8.8 5.5 2.7

4/18/03 49 23 23 1 0 1 87 313 111 9.5 9.0 5.0

3/19/03 33 23 26 2 5 0 103 274 126 11.6 9.0 7.5

2/26/03 36 13 15 7 9 11 74 34 93 6.6 4.3 3.2

1/3/03 19 7 5 9 17 9 75 62 7.2 7.5

10/29/02 27 12 10 5 15 1 81 46 146 6.0 2.8 1.8

4/9/03 26 10 9 6 6 2 32 326 64 6.9 5.4 3.1

11/16/02 26 13 11 10 8 3 55 51 93 5.9 6.3 4.3

9/18/03 44 21 19 13 3 1 72 67 94 11.4 11.3 6.4

11/5/03 23 13 10 3 8 2 113 82 145 4.4 2.8 1.3

1/19/01 23 11 8 11 12 3 91 57 175 4.1 0.6 1.7

3/5/01 18 6 5 7 6 4 225 208 232 8.2 0.7 4.3

4/16/01 24 11 10 6 1 195 195 209 5.7 4.6 4.3

9/9/03 27 16 14 3 1 0 82 54 103 9.2 5.7 3.9

9/26/02 35 13 11 4 8 0 52 41 78 5.9 4.3 2.4

9/3/03 22 11 11 3 2 0 93 77 123 4.9 3.1 2.8

10/11/02 20 5 5 2 11 0 94 58 100 7.2 4.6 3.8

7/17/03 22 21 16 4 5 2 293 281 322 5.4 2.5 3.7

PM-10 SO2 VWD SWS
14

Table 8. 

Statewide/SE PA Quarterly PM2.5 Statistics 

Summary 

EPA’s designation proposal expands the Philadelphia nonattainment area to include 

Bucks and Montgomery counties. EPA used an analysis of 2001-03 regional PM2.5

annual design values, a weighted emissions analysis, an analysis of population density, an 

analysis of population growth and an analysis of commuting patterns as the basis for the 

expansion. 

The Pennsylvania DEP disagrees with EPA’s proposed PM2.5 designation for 

Philadelphia nonattainment area. EPA’s expansion of the area will include a number of 

counties that are attaining the annual PM2.5 standard. As shown in Appendix III, Figures 

6 and 7, attainment is monitored at all sites downwind of ”Center City” and Northeast 

Philadelphia. Also, a number of flaws with EPA’s analysis supporting expansion of the 

Philadelphia nonattainment area have been identified. EPA’s methodology does not 

establish a definitive relationship between countywide emissions and the region’s design 

value monitor. In addition, it appears that EPA did not take into account the level of 

controls in the five-county Philadelphia region that have reduced NOx and VOC 

emissions by 35% even as the region’s population has increased by half a million people 

since 1980. 

A review of monitoring data in the five-county Philadelphia region indicates the region’s 

peak monitor, Chester, is being adversely affected by local sources. Unusually high 

quarterly PM2.5 concentrations in the 1st Quarter of 2001 have also affected regional 

design values. This anomaly was observed across the Commonwealth making it unlikely 

that sources in the five-county Philadelphia region were solely responsible. Both of these 

observations indicate the Philadelphia regions PM2.5 nonattainment problem is more local 

in scope and expanding the nonattainment area to include Bucks and Montgomery 

counties will not help the region attain the annual PM2.5 standard. 

Avg StDev Max Min >15.0 Sites Bris Ches BEL-F ELM-FD LAB-FD NEA-F ROX-F SOA-F VET-F Norr NewG

1st Q 2001 15.6 2.328 21.3 11.9 22 41 15.18 17.40 16.93 19.11 18.70 16.48 15.60

2nd Q 2001 16.5 2.278 25.6 13.0 32 41 15.28 17.63 15.57 16.85 16.05 14.53 15.17

3rd Q 2001 17.2 2.155 25.6 13.5 36 41 13.87 16.37 16.41 16.29 16.18 15.34 16.94

4th Q 2001 13.2 1.949 21.4 10.4 5 41 13.99 12.47 12.57 14.67 15.12 12.31 12.70

1st Q 2002 12.6 1.813 18.3 9.2 4 43 14.29 13.23 12.67 13.81 14.21 12.71 13.44 12.87 13.83

2nd Q 2002 14.5 1.931 22.1 11.4 17 44 12.23 14.16 13.44 13.61 12.81 12.73 13.63 14.73 12.85 13.32

3rd Q 2002 18.5 2.457 25.2 13.5 41 44 15.20 16.00 15.30 15.90 17.00 14.90 14.30 22.00 15.40 17.20

4th Q 2002 12.7 2.097 18.2 8.6 6 44 14.84 15.15 13.81 12.74 13.51 14.47 14.58 11.32 13.83 14.60

1st Q 2003 14.8 2.042 20.7 10.0 21 43 15.13 16.61 13.79 16.13 16.70 13.05 11.95 14.84 16.98

2nd Q 2003 14.6 1.592 19.5 11.8 12 42 14.28 16.18 13.61 13.27 13.64 12.36 14.52 13.60 15.41

3rd Q 2003 17.8 2.303 23.0 14.5 40 42 15.47 17.19 16.06 14.52 15.60 16.36 15.08 15.58 16.48

4th Q 2003 12.3 2.198 21.3 9.0 3 42 13.13 12.99 11.58 12.05 13.33 10.98 11.55 11.75 13.41
15

PITTSBURGH AREA

In the June 29, 2004 letter, EPA proposed to expand the Pittsburgh nonattainment area to 

include eight counties: Allegheny, Beaver, Butler, Westmoreland, Washington, 

Armstrong, Greene and Lawrence. Pennsylvania recommends that this area be limited to 

Allegheny, Beaver, Westmoreland and Washington counties. In addition, Pennsylvania 

strongly recommends the creation of two nonattainment areas within the Pittsburgh area 

based on strong evidence of a localized problem affecting each of these monitors. These 

two locations are the area surrounding the Liberty monitor and the area surrounding the 

North Braddock monitor. An analysis of the monitoring data shows that these two 

monitors correlate poorly with the other monitors sited in the region. 

EPA’s Analysis in Support of an Expanded Nonattainment Area 

Technical justifications for expanding the Pittsburgh PM2.5 nonattainment area were 

included in Enclosure B of EPA’s June 29, 2004 letter sent to Pennsylvania. EPA used 

nine criteria to determine which counties should be included in the Pittsburgh 

nonattainment area. These criteria included emissions, air quality, population, traffic and 

commuting patterns, expected growth, meteorology, geography/topography, jurisdictional 

boundaries, and level of emission controls. 

EPA placed a high emphasis on the weighted emissions score in its supporting document. 

EPA concluded its weighted emissions analysis showed Butler County and three adjacent 

counties, Armstrong, Greene and Lawrence, significantly contribute to the region’s 

nonattainment problem. Additional analysis factors including population density, growth 

and commuting, were also cited in support for expanding the Pittsburgh nonattainment 

area to include these counties.

Pennsylvania Recommends the Creation of Two Separate and Smaller 

Nonattainment Areas within the Larger Proposed Pittsburgh Nonattainment Area 

Figure 8 shows a display of the PM2.5 monitor locations in EPA’s proposed Pittsburgh 

nonattainment area. Take note of the three monitor names with the blue background. 

The three monitors in question are the Clairton, Liberty and North Braddock. These three 

monitors have the highest PM2.5 design values in the proposed area, as can be seen on 

Figure 9. The Liberty monitor has the highest design value in the entire Northeastern US 

at 21.2 μg/m3

. The Clairton monitor at 17.3 μg/m3 and the North Braddock monitor at 

16.9 μg/m3 are the next highest design values in the region and have values at least 1 

μg/m3

 higher than the next highest in the proposed nonattainment area (Harrison at 15.9 

μg/m3). PM2.5 concentrations of monitors surrounding the three listed above show only 

levels at or slightly above the 15.0 μg/m3 standard. After further evaluation of the data, 

we have concluded that the resulting design values at each of the three high monitors 

indicated above are due to local influences. Consequently, Pennsylvania is 

recommending that two additional, smaller nonattainment areas inside of the bigger 

Pittsburgh nonattainment area be established. These areas will consist of the five 
16

municipalities in the Liberty area and the two municipalities in the North Braddock area, 

as shown in Figure 10. 

Liberty 

The proposed Liberty nonattainment area consists of five municipalities (City of Clairton, 

Borough of Glassport, Liberty Borough, Borough of Lincoln, and Port Vue Borough). 

This area consists of the same five municipalities designated by the US EPA and thus 

codified in 40 CFR Part 81 on November 6, 1991 for being in nonattainment of the PM10

24-hour and annual standards. This area includes the Total Suspended Particulate (TSP) 

nonattainment area #8 designated in 1981. It was not yet redesignated when the PM10

standards replaced the TSP standards in 1987. 

The complexity of the largest metallurgical coke plant in the United States contributes a 

combination of particulates, sulfur dioxide, ammonia, and literally hundreds of volatile 

organic chemicals, in an atmosphere actually created by this large plant – high humidity, 

gases and materials discharged at temperatures well above 1000 degrees. Due to the 

complexity of this local area, the PM10 State Implementation Plan (SIP) required the 

development of a hybrid model. The PM10 standards were met beginning in 1998, and 

the area redesignated in 2003. 

The Liberty area will include both the Clairton (in the City of Clairton) and Liberty (in 

Liberty Borough) PM2.5 monitors. An analysis was completed to help demonstrate that 

local influences are having an effect on the PM2.5 concentrations measured at each one of 

the monitors. Pennsylvania completed a contribution assessment analysis to try to 

characterize in what concentration range most of the contribution to the design value is 

occurring. 

An analysis of the data for the Liberty area revealed the following contribution 

assessment (expressed in PM2.5 in μg/m3

). 

Site Name 0-7.5 7.5-15 15-22.5 22.5-30 30-37.5 37.5-45 45-52.5 52.5-60 60-67.5 67.5-75 Sum 

Liberty -1.2230 -1.2147 0.6456 1.4657 1.6840 1.1766 1.4001 0.8007 0.6910 0.7319 6.16

 

The design value for each day was placed in one of the categories above. For example, 

on January 1, 2003, the PM2.5 measured at Liberty was 5.6 μg/m3

. Since this value falls 

in between 0-7.5 in the above chart, the type of contribution this daily value had on the 3-

year design value (by comparing this value to 15 μg/m3

, the current annual standard for 

PM2.5) was determined. Since there were 86 measurements recorded at Liberty between 

January 1 and March 31, 2003 and knowing there are 12 quarters (12 3-month periods) in 

order to calculate the 3-year design value, the Department determined that the January 1, 

2003 contribution assessment to the 2003 design value was –0.00911 μg/m3

. If this type 

of analysis is completed for every day of measurements from January 1, 2001 through 

December 31, 2003, the values set forth in the above table will be derived. The sum of 

all values in the above table equals 6.16 μg/m3

, which shows that the design value should 

be 6.16 μg/m3

 above 15 μg/m3. See Figure 9 for verification. 
17

Subsequently, this contribution assessment analysis was completed for every site in the 

proposed Pittsburgh nonattainment area. The contribution assessment average for all 

sites, not including the Liberty, Clairton, and North Braddock monitors is set forth below: 

Site Name 0-7.5 7.5-15 15-22.5 22.5-30 30-37.5 37.5-45 45-52.5 52.5-60 60-67.5 67.5-75 Sum

All Sites -1.6630 -1.6763 0.7806 0.8994 0.7594 0.3327 0.2024 0.2752 0.0174 0.0000 -0.07

 

For comparison, the results from Liberty analysis are shown again as follows: 

Site Name 0-7.5 7.5-15 15-22.5 22.5-30 30-37.5 37.5-45 45-52.5 52.5-60 60-67.5 67.5-75 Sum

Liberty -1.2230 -1.2147 0.6456 1.4657 1.6840 1.1766 1.4001 0.8007 0.6910 0.7319 6.16

 These data show the following: 

1. The heavy contribution of Liberty’s design value from 22.5 μg/m3

 and up as is 

significantly larger than the regional average. 

2. There are a lot more days when the regional concentration is at 15 μg/m3 as 

compared with the Liberty monitor. 

3. The regional average sum shows that the regional values have a negative impact 

on the design value, which, in turn, would allow the monitor to be below the 15 

μg/m3 annual threshold. 

The main question remains: Why is the Liberty monitor so much higher than the regional 

average? Graph 2 below shows Liberty’s categorical breakdown, compared with 

Clairton, North Braddock and the regional average. As can be seen from the above 

analysis and Graph 2, the answers should lie in the range of 22.5 μg/m3 and higher range 

of concentrations. The remainder of the contribution assessment analysis will focus on 

the higher range of concentrations. 
18

Graph 2 

The Department also completed a day-to-day comparison of actual measured PM2.5

concentrations at Liberty to the regional average. This range was selected to focus on 

the Liberty’s values that were considerably higher than the regional average to in order to 

determine what was contributing to Liberty’s high values. The day-to-day variance in 

standard deviation was determined and the daily difference in the Liberty value to that of 

the region was also calculated. The analysis also evaluated a certain number of days set 

to the criteria above (days where Liberty was at least one standard deviation greater than 

the regional average) and days when the regional levels were above 15 μg/m3 and the 

Liberty values were above 22.5 μg/m3

. 

In addition, the meteorology that was occurring at the monitor was also examined. The 

Liberty monitor measures meteorological parameters, including wind speed and wind 

direction. In fact, Figure 11 shows a wind rose at the Liberty monitor from January 1, 

2001 through December 31, 2003. The daily average wind direction over the three-year 

period was compared to those values with the daily PM2.5 concentrations at the Liberty 

monitor. Subsequently, this wind data was linked to the corresponding high days for 

Liberty as compared with the regional average. Based on the Department’s analysis, 

there were over 200 days during the three- year period where the Liberty concentrations 

were at least one standard deviation over the regional average. It is important to note that 

samples are taken at Liberty every day (1 in 1 monitor). However, the wind analysis on 

the top 50 days (top 25% of the 200 days) with regards to the days being ranked from 

highest to lowest with respect to the difference of Liberty’s concentration to the rest of 

the region. Figure 12 shows the wind directions for these top 50 days plotted in a 

geographic information system (GIS) application. On more than 80% of the days, the 
19

wind flow from the southwest, flowing right over top an industrial source is observed. 

This source is a possible contributor to the PM2.5 problem being experienced in Liberty, 

with the following emissions (direct PM emissions from filterable and condensable 

measurements and SO2 and NOx emissions that form sulfates and nitrates, constituents in 

secondary PM2.5 formation): 

Source Name Inventory Year NO2 PM2.5 PM10 PT 

PM 

Cond SO2 

Liberty Area Industrial Source 2002 5764.22 319.04 740.52 2461.20 109.06 1251.56

In November 1999, the Allegheny County Health Department (ACHD) began conducting 

continuous PM2.5 sampling at the Liberty monitor. Back in October 2003, the ACHD 

began conducting speciation monitoring at the Liberty monitor (a monitor which was 

moved from the Hazlewood monitoring location). An analysis was completed with the 

eight months (October 2003 through May 2004) of data that currently exists for Liberty 

monitor and then compared with other regional urban and rural sites. In fact, the PM2.5

being measured at the Liberty monitor is unique since it is unlike any other urban and 

rural PM2.5 monitor. The details of the analysis are below. 

First, we examined the PM2.5 continuous data from multiple monitoring locations across 

the Mid-Atlantic into the Northeast. We were able to look at the 2002 average diurnal 

cycle of PM2.5 at each of those monitors. Graph 3 displays the result. 

Graph 3 

The black line (with the white circles) displays the plot for the Liberty monitor. All of 

the other monitors are labeled on the right with their respective AIRS code as 

designation. The analysis immediately shows that the diurnal cycle displayed at Liberty 

is unlike that displayed at other monitored locations. The average difference between 

nighttime Liberty measurements and the other monitors’ measurements is on the order of 

10 to 15 μg/m3

 higher. This is mainly because of the river valley that encompasses the 
20

Liberty monitor. The higher peaks in the overnight hours are likely a result of a 

meteorological phenomenon known as an inversion. An inversion sets up as a result of 

high pressure positioned over the area or clear nights allowing the radiational cooling of 

the earth’s surface. When these inversions form, vertical mixing of air masses ceases. 

Since the cool air is displaced below the warmer air, the air will be unable to rise. In air 

quality terms, the PM2.5 concentrations will be concentrated near the surface. A local 

emission source, such as that seen in Figure 12, will then play an even bigger role in 

affecting air quality since most of the emission sources at the facility are unable to 

penetrate the inversion, thus remaining trapped near the surface. 

The second part of our analysis dealt with the speciated components of PM2.5 at the 

Liberty monitor compared with values at the ACHD operated Lawrenceville monitor. 

Only utilizing the data from October 2003 to May 2004, we were able to create graphs 

displaying the distribution of the major components of PM2.5 (sulfates, nitrates, carbons 

and ammonium). The Lawrenceville monitor is placed in a more urban environment than 

the Liberty monitor. 

Our analysis first focused on the sulfates and nitrates. For the most part, the sulfates and 

nitrates matched up pretty well, as can be see in Graph 4 for sulfates and Graph 5 for 

nitrates. 

Graph 4 
21

Graph 5 

These speciated values are fairly consistent with the sulfates and nitrates experienced 

across the other regional speciated monitors. 

The second part of our speciated analysis consisted of carbon (elemental and organic) and 

ammonium. Overall, vast differences between the Liberty and Lawrenceville were 

monitored. Graph 6 displays the elemental carbon, Graph 7 shows the organic carbon, 

and Graph 8 shows the ammonium. 

Graph 6 
22

Graph 7 

Graph 8 

The three graphs above display the variation of the carbon and ammonium portion of 

PM2.5. On the days when the Liberty monitor was high, the ammonium, organic and 

elemental carbon peak to levels higher than the Lawrenceville monitor. These graphs 

display that there is some sort of local phenomenon (most likely a local emission source) 

that is influencing the PM2.5 concentrations being reported at the Liberty monitor. 
23

Therefore, we strongly recommend that the proposed Liberty area be designated as a 

separate PM2.5 nonattainment area. Local influences, such as those from the industrial 

source labeled above, are contributing to the additional PM2.5 being measured at the 

Liberty monitor. 

North Braddock 

The proposed North Braddock nonattainment area consists of two municipalities 

(Braddock Borough and North Braddock Borough). The proposed North Braddock area 

includes the TSP nonattainment area designated as area #6 in 1981. It was not yet 

redesignated when the PM10 standards replaced the TSP standards in 1987. It was also 

listed as a Group II PM10 area in 1987, “where attainment of the PM10 NAAQS is 

uncertain,” likely due to the emission of the local steel plant. A Group II area SIP was 

submitted in 1988. The primary source of emissions in this area is a steel plant that is 

sited on a riverfront and affects the communities along the river and up the hillside. 

The North Braddock area will include the North Braddock (in North Braddock Borough) 

PM2.5 monitor. The analysis that the Department has completed demonstrates that local 

influences are having an effect on the PM2.5 concentrations measured at each one of the 

monitors. Pennsylvania completed a contribution assessment analysis to characterize in 

what concentration range most of the contribution to the design value is occurring. 

The Department initially evaluated data for the North Braddock area and observed the 

following contribution assessment expressed in PM2.5 in μg/m3). 

Site Name 0-7.5 7.5-15 15-22.5 22.5-30 30-37.5 37.5-45 45-52.5 52.5-60 60-67.5 67.5-75 Sum

North 

Braddock -1.2247 -1.3675 1.0383 1.2770 0.9955 0.5594 0.2116 0.2683 0.1497 0.0000 1.91

The design value for each day is included in one of the above categories. For example, 

on January 4, 2003, the PM2.5 measured at North Braddock was 11.7 μg/m3. Since this 

value falls in between 0-7.5 in the above chart, the type of contribution this daily value 

had on the 3-year design value (by comparing this value to 15 μg/m3

, the current annual 

standard for PM2.5) was calculated. Since there were 20 measurements recorded at North 

Braddock between January 1 and March 31, 2003 and knowing there are 12 quarters (12 

3-month periods) in order to calculate the 3-year design value, the Department 

determined that the January 4, 2003 contribution assessment to the 2001-2003 design 

value was –0.01375 μg/m3. If this type of analysis is completed for every day of 

measurements from January 1, 2001 through December 31, 2003, the values set forth in 

the above table will be achieved. The sum of all values in the above table equals 1.91 

μg/m3

, which shows that the design value should be 1.91 μg/m3 above 15 μg/m3. See 

Figure 9 for verification. 

The Department also completed this contribution assessment analysis for every site in the 

proposed Pittsburgh nonattainment area. The contribution assessment average for all 

sites, not including the Liberty, Clairton, and North Braddock monitors is set forth below: 
24

Site Name 0-7.5 7.5-15 15-22.5 22.5-30 30-37.5 37.5-45 45-52.5 52.5-60 60-67.5 67.5-75 Sum

All Sites -1.6630 -1.6763 0.7806 0.8994 0.7594 0.3327 0.2024 0.2752 0.0174 0.0000 -0.07

The following results from North Braddock analysis are provided below for comparison 

purposes. 

 

Site Name 0-7.5 7.5-15 15-22.5 22.5-30 30-37.5 37.5-45 45-52.5 52.5-60 60-67.5 67.5-75 Sum

North 

Braddock -1.2247 -1.3675 1.0383 1.2770 0.9955 0.5594 0.2116 0.2683 0.1497 0.0000 1.91

 Based on the data in these two tables the following should be noted: 

1. The heavy contribution of North Braddock’s design value from 15 μg/m3

 through 

to 45 μg/m3

 as compared to regional average. 

2. There are a lot more days when the regional concentration is at 15 μg/m3

 as 

compared with the Liberty monitor. 

3. The regional average sum shows that the regional values have a negative impact 

on the design value, which, in turn, would allow the monitor to be below the 15 

μg/m3 annual threshold. 

The main question remains: Why is the North Braddock monitor so much higher than the 

regional average? Graph 2 (in the Liberty section) shows North Braddock’s categorical 

breakdown, compared with Clairton, Liberty and the regional average. As can be seen 

from the above analysis and Graph 2, the answers should lie in the range of 15 and 45 

μg/m3

 concentrations. The remainder of the contribution assessment analysis will focus 

in the 15 – 45 μg/m3 range. 

The Department also completed a day-to-day comparison of actual measured PM2.5

concentrations at North Braddock to the regional average. The range of North 

Braddock’s values that were considerably higher than the regional average were 

evaluated to determine, if possible, the factors contributing to North Braddock’s high 

values. During this analysis the day-to-day variance in standard deviation and the daily 

difference in the North Braddock value to that of the region were determined. 

Subsequently, an analysis on a certain number of days set to the criteria above (days 

where North Braddock was at least one standard deviation greater than the regional 

average) was considered as well as the days when the regional levels were above 15 

μg/m3

 and the Liberty values ranged from 15 to 45 μg/m3. 

The Department also evaluated the meteorological conditions occurring at the monitor. 

The North Braddock monitor used to measure meteorological parameters, including wind 

speed and wind direction, between 1990 and 2000. For this portion of the analysis, the 

Department considered two of the years: 1999 and 2000 since both of these years have 

measured PM 2.5 and meteorological parameters. Figure 13 shows a wind rose at the 

North Braddock monitor from January 1, 1999 through December 31, 2000. The general 

wind flow through the river valley should be noted. There is a substantial amount of 

wind flow from the northwest and again out of the southeast. The Department calculated 
25

the daily average wind direction over the three-year period and compared those values 

with the daily PM2.5 concentrations at the Liberty. This wind data was linked to 

corresponding high days for Liberty as compared with the regional average. Based on 

the analysis, there were 45 days during the two-year period where the Liberty 

concentrations were at least one standard deviation over the regional average. It is 

important to note that samples are taken at Liberty every third day (1 in 3 monitor). 

Therefore, the wind analysis is based on the top 12 days (top 25% of the 45 days) with 

regards to the days being ranked from highest to lowest with respect to the difference of 

Liberty’s concentration to the rest of the region. Figure 14 shows the wind directions for 

these top 12 days plotted in a GIS application. On more than 80% of the days, the wind 

flow from the southeast, flowing right over top an industrial source is observed. This 

source is a possible contributor to the PM2.5 problem being experienced in North 

Braddock, with the following emissions (direct PM emissions from filterable and 

condensable measurements and SO2 and NOx emissions that form sulfates and nitrates, 

constituents in secondary PM2.5 formation): 

Source Name 

Inventory 

Year NO2 PM2.5 PM10 PT PMCond SO2 

North Braddock Industrial Source 2002 298.17 291.23 359.47 494.71 671.03 1356.49

Unfortunately, the North Braddock monitor lacks continuous and speciated monitored 

data so that the same type of comparison, as was concluded with the Liberty monitor 

above, cannot be completed. The Department feels that if the continuous and speciated 

data were to exist, it would show a similar result as that displayed at the Liberty monitor. 

Based on this analysis, the proposed North Braddock area should be designated as a 

separate PM2.5 Nonattainment area. Local influences, such as those from the industrial 

source labeled above, are contributing to the additional PM2.5 being measured at the 

North Braddock monitor. 

Pennsylvania’s Additional Comments Regarding EPA’s Analysis 

Greene County. Greene County is adjacent to the Pittsburgh MSA. Greene County is a 

rural, non-industrial county with very low population data and VMT. Emissions from 

Greene County are dominated by a single power plant, Allegheny Energy Supply’s 

Hatfield’s Ferry Power Station that is equipped with low NOx cell burners and ESPs. 

One of the units has rotating over-fire air and selective non-catalytic reducer (SNCR). 

Emissions from this single facility account for 99.5% of the county’s SO2 emissions and 

86.1% of the NOx emissions. This plant will also be subject to the Best Available 

Retrofit Technology (BART) requirement under the regional haze program. As discussed 

previously, Pennsylvania believes that a national or regional multi-pollutant rule is the 

appropriate mechanism to address emissions from large point sources. Adding Greene 

County to the Pittsburgh nonattainment area is not a logical or efficient way to address 

the emissions from the county’s power plant. Pennsylvania recommends that EPA 

designate Greene County as attainment. 
26

Butler County. Butler County contains no significant sources of emissions. Therefore, 

it does not contribute to the PM2.5 nonattainment levels monitored elsewhere in the 

Pittsburgh MSA. Based on monitored PM2.5 levels in similar non-urban, non-industrial 

counties, there is no reasonable basis to conclude that this county should be 

nonattainment. Figure 9 demonstrates monitored attainment in the adjacent counties of 

Mercer and Indiana. In addition adjacent monitors in Allegheny County also show 

attainment. After reviewing EPA’s weighted emissions scoring data for the Pittsburgh 

Area, it is apparent that Butler County scores very low in EPA’s own emission-weighting 

scheme. Additionally, the county has low population density and VMT. Based on all of 

these factors, DEP remains convinced that it is inappropriate to designate Butler as 

nonattainment for the PM2.5 standard. 

Armstrong County. Armstrong County was not included in the Pittsburgh MSA as 

defined by OMB in the June 30, 1999 definitions. It was added to the Pittsburgh MSA in 

the June 2003 OMB report. Armstrong County has very low population density and 

VMT. County population is projected to decline substantially over the next decade. In 

addition, DEP has collected monitoring data from a TEOM monitor in the Kittanning 

area. This monitor averaged 14.3 ug/m3

 (2001 – 2003 data) demonstrating that the 

county has PM2.5 levels that achieve the standard. Armstrong County does have 

substantial emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx). However, 

virtually all (99.8 % of the SO2 and 86.4% of the NOx) of these emissions can be 

attributed to the county’s two large power plants, Armstrong and Keystone. The 

Armstrong plant is equipped with rotating over-fire air, ESPs and low NOx burners. The 

larger of these two plants, Keystone, is located on Armstrong County’s eastern border 

and is equipped with SCR on both units to reduce emissions of nitrogen oxides. An 

examination of the wind rose from Pittsburgh supports the conclusion that these emission 

sources would have virtually no impact on the monitors in the Pittsburgh area that are 

monitoring nonattainment of the PM2.5 standard. In addition, it has long been 

Pennsylvania’s position that it is imperative that emissions from large point sources 

including power plants, be addressed through a consistent national or regional control 

program. EPA’s recently proposed CAIR would be an appropriate mechanism for 

addressing these emissions provided more stringent emission caps and timely compliance 

schedules are promulgated. 

Examining EPA’s weighted emissions scoring process for Armstrong and Washington 

demonstrates that absurd conclusions can be drawn from EPA’s ranking process. 

Washington County rates a weighted emissions score of 10.6. Depending on the “cut 

point” chosen, this would normally indicate that based on emissions this county could be 

excluded from the nonattainment area. Armstrong County had a weighted emissions 

score of 60.6 making it higher than Allegheny County, where the major nonattainment 

values exist. The problem is, interestingly, that Armstrong County monitors attainment 

while Washington County, with a five-fold lower weighted emissions score, monitors 

nonattainment. Clearly, the recently developed weighed emissions scoring rating process 

must be employed with extreme caution or merely disregarded. 
27

Lawrence County. Lawrence County was not included in the Pittsburgh MSA in the 

June 30, 1999 OMB definitions. OMB’s June 10, 2003 report added Lawrence County to 

the Pittsburgh MSA. For ozone, Lawrence County has historically been a stand-alone 

planning area not included in the Pittsburgh nonattainment area. Lawrence County has 

relatively low and declining population density. Lawrence County also has relatively low 

emissions and the bulk of the SO2 emission (81%) would be addressed by EPA’s 

proposed CAIR provided more stringent emission caps and timely compliance schedules 

are promulgated. These emissions are from the older, small New Castle power plant 

located in the county and covered by BART. All three of the units at the plant are 

controlled by SNCR and ESPs. Based on a review of the available data, DEP believes 

that attainment is the correct designation for Lawrence County. 

 

READING AREA

Pennsylvania concurs with EPA’s proposed nonattainment designation for Berks County. 

YORK AREA

There is a discrepancy in the York PM2.5 annual design value. EPA’s analysis indicates 

the 2001-03-design value is 17.3 μg/m3. Our analysis indicates York’s design value is 

slightly lower, 17.1 μg/m3

. 

Pennsylvania concurs with EPA’s proposed nonattainment designation for York County. 

YOUNGSTOWN AREA

On June 29, 2004 EPA released their intended PM2.5 designations for Pennsylvania. EPA 

expanded the Youngstown, Ohio nonattainment to include Mercer County. Three other 

Ohio counties, Columbiana, Mahoning and Trumbull, were included in the Youngstown 

nonattainment area. The design monitor for the Youngstown nonattainment area is in 

Mahoning County and has an annual PM2.5 design value of 15.2 μg/m3

. EPA’s report 

lists Mercer County’s design value as 14.3 μg/m3. Pennsylvania’s records indicate 

Mercer County’s design value is slightly lower at 14.2 μg/m3

. 

EPA’s Analysis in Support of an Expanded Nonattainment Area 

EPA noted a couple of factors supporting the addition of Mercer County into the 

Youngstown nonattainment area. The first was the inclusion of Mercer County in the 

2003 MSA. Additional factors include moderate contributions from population and 

commuting. 

Pennsylvania’s Comments Regarding EPA’s Analysis 

Mercer County should not be included in the Youngstown nonattainment area. The 

following comments to EPA’s analysis: 
28

Youngstown MSA: EPA’s primary reason for including Mercer County in the 

Youngstown nonattainment area was its inclusion in the Youngstown MSA. MSA 

boundaries were not restricting factors in other nonattainment areas in Pennsylvania. 

This application appears inconsistent. 

Monitored Values: The Mercer County monitor is well below the annual PM2.5

standard. Placing a county that’s monitoring attainment into a nonattainment area will 

cause difficulties in communication and emission control program implementation. 

Local officials and citizens will question the legitimacy of imposing control measures on 

an area that is attaining the standard and has not been shown definitely to be contributing 

to a nonattainment problem. 

Mercer County Emissions: Emissions from Mercer County are significantly less than 

the emissions of either Trumball or Mahoning counties. The same is true for Columbiana 

County in Ohio. In fact, the combined emissions of Mercer and Columbiana counties are 

well below the emissions of either Trumball or Mahoning counties. Emissions from 

Mercer County will have little or no effect on the design monitor since predominant 

winds place the county downwind of the Youngstown region. 

Mercer County’s Population: Mercer County’s population trends do not support 

adding this Pennsylvania county to the Youngstown nonattainment area. Census figures 

indicate the county’s population has decreased over the last 20 years, though numbers 

seem to have stabilized in the 1990s. 

Mercer County VMT: Mercer County’s VMT is approximately half of either Mahoning 

or Trumbull counties. Demographics show Mercer County’s work-age population (15-64 

year olds) has decreased by 1.5% between 1990 and 2000. This should place a ceiling on 

future VMT, if it is directly related.