1 

### Delaware Area Designations for the
20 08 Ozone National Ambient Air Q uality Standard s

In March 2009, the State of Delaware recommended a large, multi

- state nonattainment area, covering the entire States of Delaware, Maryland, Michigan, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Virginia, and West Virginia , plus the District of Columbia

. Alternatively, Delaware recommended that the entire State of Delaware be designated as a stand

alone nonattainment area. In October 2011, Delaware updat ed its recommendations. In that letter, Delaware expanded its recommended large multi

- state nonattainment area to include the States of Kentucky, Indiana, Illinois, Missouri, Tennessee, and Wisconsin. In addition, in its October 2011 letter, the State of Delaware specified that if EPA did not accept either of its designation options, then Kent County should not be designated nonattainment. That
recommendation wa s based on 2008

- 2010 data and preliminary 2009

- 2011 data. On February 29, 2012, Delaware submi tted comments on EPA’s preliminary nonattainment area boundary
decisions. In th at letter , Delaware commented on EPA’s intended nonattainment area boundaries as well as EPA’s methodology for determining those boundaries. Delaware also commented on
EPA’s r ejection of the large multi

- state nonattainment area.

EPA has addressed Delaware’s comments in the Responses to Significant Comments on the State and Tribal Designation Recommendations for the 2008 Ozone National Ambient Air Quality
Standards document in the docket for these designations. In section 3.1.2 of this document, EPA addresses the concept of a large, multi

- state nonattainment area and states that we do not believe that creation of a super

- regional nonattainment area to address pollution transp ort is the appropriate approach. As an initial matter, Clean Air Act (CAA) section 107(d)(1) provides that areas designated nonattainment should include any “nearby” area contributing to a violation of the NAAQS. We believe that broad super

- regional areas go beyond this by including areas that are not necessarily “nearby” but contribute to nonattainment through long

- range transport. The CAA has separate provisions to address this phenomenon. Section 110(a)(2)(D) requires states to address ozone transport t hat contributes to a violation of the NAAQS in another State. In addition, section 184, creates the northeast ozone transport region and also grants EPA authority to establish additional transport regions, as appropriate. Finally, we note that the approac h taken by EPA is consistent with the approach Congress specified for serious and above areas for the 1

- hour NAAQS, where in section 107(d)(4)A), Congress set the Consolidated Metropolitan
Statistical Area ( CMSA ) boundaries as the presumptive boundaries of the nonattainment area. In
Catawba Co. v. EPA 1 , the Court upheld that “contribute” under §107(a)(1)(A) of the CAA does not necessarily mean “any contribution” to nonattainment but rather a degree of contribution sufficient to deem an area nonattainment, that is, sufficient enough to warrant designation as nonattainment. “Section 107(d) is ambiguous as to how EPA should measure contribution and what degree of contribution is sufficient to deem an area nonattainment ...” Catawba County v.
EPA , 571 F.3d 20 , 39 (D. C. Cir. 2009) (Internal citation omitted but with emphasis added)

. “Thus, reasonably exercising the discretion that Congress delegated to it, EPA interpreted “contribute” to mean “sufficiently contribute,” and then applied the CMSA presumption and
nine

- fa ctor test precisely to identify those areas that meet that definition.” Id.

1 Catawba County v. EPA , 571 F.3d 20, (D.C. Cir. 2009)2 For the reasons stated above, EPA does not intend to designate a large nonattainment area as suggested by Delaware.

The table below identifies the areas and associated counties or pa rts of counties in Delaware that
EPA is designat ing as nonattainment for the 2008 ozone national ambient air quality standards (2008 ozone NAAQS). In accordance with section 107(d) of the Clean Air Act, EPA must designate an area “nonattainment” if it is violating the 2008 ozone NAAQS or if it is contributing to a violation of the 2008 ozone NAAQS in a nearby area. The technical analyses supporting the boundaries for the individual nonattainment areas are provided below.

Nonattainment Areas in Delaware

Area Delaware Recommended
Nonattainment Counties EPA’s Designated
Nonattainment Counties Philadelphia

- Wilmington

Atlantic City , PA

- NJ

- MD

DE none New Castle

Seaford , DE none Sussex The Philadelphia

- Wilmington

- Atlantic City , PA

- NJ

- MD

- DE Area is a multi

- state nonattainment
area. Table 1 in the Technical Analysis for the Philadelphia

- Wilmington

- Atlantic City , PA

- NJ

MD

- DE Area, below, identifies the counties in the other states that EPA is designat ing as part of
the nonattainment area.

EPA is designat ing the remaining county in Delaware that is not listed in the table above , Kent County, as “unclassifiable/attainment ” for the 2008 ozone NAAQS.

The analysis below provides the basis for the nonattainment area boundaries. It relies on our analysis of whether and which monitors are violating the 2008 ozone NAAQS, based on certified air quality monitoring data from 2008

- 2010 and an evaluation of whe ther nearby areas are contributing to such violations. EPA has evaluated contributions from nearby areas based on a weight of evidence analysis considering the factors identified below. EPA issued guidance on December 4, 2008 that identified these factor s as ones EPA would consider in determining ozone nonattainment area boundaries and recommended that states consider these factors in making their designation recommendations to EPA. 2

1. Air quality data (including the design value calculated for each FRM or FEM monitor in the area);
2. Emissions and emissions

- related data (including location of sources and population, amount of emissions and emissions controls, and urban growth patterns);
3. Meteorology (weather/transport patterns);
4. Geography and topography (mou ntain ranges or other basin boundaries);

2 The December 4, 2008 guidance memorandum “Area Designations for the 2008 Revised Ozone National Ambient Air Quality Standards” refers to 9 factors. In this technical support document we have grouped the emissions

related factors together under the headin g of “Emissions and Emissions

- Related Data

, ” which results in 5 categories
of factors.3 5. Jurisdictional boundaries (e.g., counties, air districts, existing nonattainment areas, Indian country, metropolitan planning organizations (MPOs))

Ground

- level ozone is not emitted directly into the air, but is cr eated by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC) in the presence of sunlight. Because NOx and VOC emissions from a broad range of sources over a wide area typically contribute to violations of the ozone sta ndards, EPA believes it is important to consider whether there are contributing emissions from a broad geographic area. Accordingly, EPA chose to examine the 5 factors with respect to the larger of the Combined Statistical Area (CSA) or
Core Based Statist ical Area (CBSA) within which is located the violating monitor(s). 3 All data and information used by EPA in this evaluation are the latest available to EPA and/or provided to EPA by states or tribes.

In EPA’s designations guidance for the 2008 ozone NAAQ S EPA recommended examining CSA/CBSAs because certain factors (such as population) used to establish CSAs and CBSAs are similar to the factors EPA is using in this technical analysis to determine if a nearby area is contributing to a violation of the 2008 ozone NAAQS. EPA used the same basic approach in the designation process for the 1997 ozone NAAQS. Where a violating monitor is not located in a CSA or CBSA, EPA’s guidance recommended using the boundary of the county containing the violating monito r as the sta rting point for considering th e nonattainment area’s boundary.

3 Lists of CBSAs and CSAs and their geographic components are provided at www.census.gov/popu lation/www/metroareas/metrodef.html . The lists are periodically updated by the Office of Management and Budget. EPA used the most recent update, based on 2008 population estimates, issued on December 1, 2009 (OMB Bulletin No. 10

- 02).4 Technical Analysis for the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD Area

Figure 1 is a map of the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD nonattainment

area

. The map provides other relevant information including the locations and 2010 design values of air quality monitors , county and other jurisdictional boundaries

. The map shows the boundaries of the Philadelphia

- Camden

- Vineland, PA

- NJ

- DE

- MD CSA, the existi ng nonattainment area boundary for the 1997 ozone NAAQS, and EPA’s nonattainment boundary for the 2008 ozone NAAQS.

Figure 1.

For purposes of the 1997 8

- hour ozone NAAQS, much of this area was designated nonattainment. The Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- MD

- DE nonattainment area
at that time included the entire counties of Kent, Ne w Castle, and Sussex in Delaware; Ceci l in Maryland ; Atlan tic, Burlington, Camden, Cape May, Cumberland, Gloucester, Mercer, Ocean, and Salem in New Jersey; and Bucks, Chester, Delaware, Montgomery, and Philadelphia in Pennsylvania.

In March 2009, the State of Delaware recommended that no co unties in Delaware be included in
the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD area for the 2008 ozone NAAQS based on air quality data from 2006

- 2008. Instead, Delaware recommend a large, multi

- state nonattainment area, covering the entire State s of Delaware, Maryland, Michigan, New Jersey,5 New York, North Carolina, Ohio, Pennsylvania, Virginia, and West Virginia, and the District of Columbia. Alternatively, Delaware recommended that the entire State of Delaware be designated as a stand

- alone no nattainment area. In October 2011, Delaware updated its recommendations. In that letter, Delaware expanded its recommended large multi

- state nonattainment area to include the States of Kentucky, Indiana, Illinois, Missouri, Tennessee, and
Wisconsin. In a ddition, in its October 2011 letter, the State of Delaware specified that if EPA did not accept either of its designation options, then Kent County should not be designated nonattainment.
This recommendation was based on 2008

- 2010 data and continues to be true based on preliminary
2009

- 2011 data. The data are from Federal Reference Method (FRM) monitors or Federal Equivalent Method (FEM) monitors sited and operated in a ccordance with 40 CFR Part 58. (See the March 18, 2009 letter from Governor Jack A. Mar kell to EPA, received on April 3, 2009; and the October 28, 2011 letter from the Delaware Department o f Natural Resources a nd
Environmental Control

. )

In March 2009, the State of Maryland recommended that Cecil County be designated as
nonattainment as part of the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD area for the 2008 ozone NAAQS based on air quality data from 2006

- 2008. This is the same Maryland County that was included in the Philadelphia

- Wilmington

- Atlantic City nonattainment area for
the 1 997 ozone NAAQS. This recommendation was based on data from FRM monitors or FEM monitors sited and operated in accordance with 40 CFR Part 58. (See the March 10, 2009 letter
from Governor M artin O’M alley to EPA, rece i v ed on March 16, 2009.) EPA has confirmed that the area is still nonattainment, based on the design value for 2010, which uses data from 2008 through 2010.

In April 2009, the State of New Jersey recommended that the same nine counties in New Jersey
that were included in the Phi ladelphia

- Wilmington

- Atlantic City nonattainment area for the 1997 ozone NAAQS be designated as nonattainment in the Philadelphia

- Wilmington

- Atlantic City,
PA

- NJ

- DE

- MD area for the 2008 ozone NAAQS based on air quality data from 2006

- 2008.
This recommenda tion was based on data from FRM monitors or FEM monitors sited and operated in accordance with 40 CFR Part 58. (See the April 1, 2009 letter from the New Jersey
D epartment o f Environmental Protection to EPA.) EPA has confirmed that the area is still

nona ttainment, based on the design value for 2010, which uses data from 2008 through 2010.

In March 2009, the Commonwealth of Pennsylvania recommended that the same five counties in Pennsylvania that were included in the Philadelphia

- Wilmington

- Atlantic City nonattainment area for the 1997 ozone NAAQS be designated as nonattainment in the Philadelphia

Wilmington

- Atlantic City, PA

- NJ

- DE

- MD for the 2008 ozone NAAQS based on air quality data
from 2006

- 2008. Pennsylvania provided an update to the original recomme ndation in November
2011 based on air quality data from 2009

- 2011. That recommendation was to remove Chester
and Delaware Counties from the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD , and designate those counties as attainment. This recommendatio n was based on data from FRM monitors or FEM monitors sited and operated in accordance with 40 CFR Part 58. (See the March 17, 2009 and November 22, 2011 letter s from the Pennsylvania Department of
Environmental Pro tection to EPA.)

After considering th ese recommendations and based on EPA's technical analysis described below, EPA is designating 16 counties in Delaware, Maryland, New Jersey, and Pennsylvania6 (identified in Table 1 below) as “nonattainment” for the 2008 ozone NAAQS as the Philadelphia

- Wilm ington

- Atlantic City, PA

- NJ

- DE

- MD nonattainment area.

Table 1. State's Recommended and EPA’s Designated Nonattainment Counties for the Philadelphia

- Wilmington

- Atlantic City , PA

- NJ

- MD

- DE Area

. Philadelphia State

- Recommended
Nonattainment Counties Counties Designated by EPA

as Nonattainment
Delaware None New Castle Maryland Cecil Cecil

New Jersey Atlan tic, Burlington, Camden, Cape May, Cumberland, Gloucester, Mercer, Ocean, and Salem Atlan tic, Burlington, Camden, Cape May, Cumberland, Gloucester, Mercer, Ocean, and Salem

Pennsylvania Bucks, Montgomery, and Philadelphia Bucks, Chester, Delaware, Montgomery, and Philadelphia

Factor Assessment

The counties evaluated in this analysis include all counties in the Philadelphia

- Camden

Vineland, PA

- NJ

- MD

- DE CSA plus the counties outside the CSA that were included in the Philadelphia

- Wilmington

- Atlantic City nonattainment area for the 1997 ozone NAAQS. A more detailed meteorological assessment is included in a factor a ssessment for New Jersey’s request
for Ocean and Mercer Counties is attached.



### Factor 1: Air Quality Data

For this factor , we considered 8

- hour o zone design values (in parts per billion (ppb)) for air quality monitors in counties in the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD area
based on data for the 2008

- 2010 period (i.e., the 2010 design value, or DV) , which are the most

recent years with fully

- certified air quality data for the entire area

.

However, Pennsylvania submit ted certified 2011 air quality data to EPA in November 2011. The only effect of using 2011 data is a slight change in the highest design value for the nonattainment area and the location of the highest design value. Since none of the other states in the

n onattainment area submitted certified 2011 data to EPA while EPA was in the process of evaluating the states submittal, that is, though March 2011, EPA is using 2010 ozone data as the last year of data for evaluation of these requests. In ordinary circums tances, EPA does not use data from different years in different parts of nonattainment areas. The effects of using 2011 data from Pennsylvania are noted in Appendix C.

A monitor’s DV is the metric or statistic that indicates whether that monitor attains a specified air quality standard. The 2008 o zone NAAQS are met when the annual f ourth

- highest daily
maximum 8

- hour average concentration, averaged over 3 years is 0.075 ppm or less

. A DV is only valid if minimum data completeness criteria are met. See 4 0 CFR part 50 App endix P

. Where several monitors are located in a county (or a designated nonattainment area or maintenance area ), the DV for the county or area is determined by the monitor with the highest
level.7 Note: Monitors that are eligible for pro viding design value data generally include State and Local Air Monitoring Stations (SLAMS) that are sited in accordance with 40 CFR Part 58, Appendix D (Section 4.1) and operating with a federal reference method (FRM) or federal equivalent method (FEM) mon itor that meets the requirements of 40 CFR part 58, appendix A. All data from a special purpose monitor (SPM) using an FRM or FEM which has operated for more than 24 months is eligible for comparison to the NAAQS unless the monitoring agency
demonstrates t hat the data came from a particular period during which the requirements of appendix A (quality assurance requirements) or appendix E (probe and monitoring path siting criteria) were not met.

The 2010 DVs for the o zone NAAQS for counties in the Philadelphia

- Wilmington

- Atlantic City,
PA

- NJ

- DE

- MD CSA and several nearby surrounding counties are shown in Table 2

.

Table 2 . Air Quality Data

.

County State Recommended
Nonattainment? 2010 8

- hour Ozone DV (ppb)
Atlantic, NJ Yes 74
Berks, PA Yes, other area 79
Bucks, PA Yes 83 Burlington, NJ Yes

-- Camden, NJ Yes 80 Cape May, NJ Yes

-- Cecil, MD Yes 80
Chester, PA No 76
Cumberland, NJ Yes 76
Delaware, PA No 74
Gloucester, NJ Yes 81
Kent, DE No 74
Mercer, NJ Yes 78 Montgomery, PA Yes 78
New Castle, DE Yes, other area 76
Ocean, NJ Yes 81 Philadelphia, PA Yes 82
Salem, NJ Yes

-- Sussex, DE Yes, other area 77

Note: Counties with no ozone monitor are identified with “

-- “ in the 2010 8

- hour Ozone DV column

.

In accordance with section 107(d) of the Clean Air Act, EPA must designate an area
nonattainment if it is violating the 2008 ozone NAAQS. New Castle and Sussex Counties in
Delaware ; Cecil County, Maryland; Berks, Buck s , Montgomery, and Philadelphia Counties in Pennsylvania; and Cam den, Cumberland, Gloucester, Mercer, and Ocean Co unties in New Jersey show violations of the 2008 ozone NAAQS . Therefore , these counties must be included
in a nonattainment area. A cou nty (or partial county) must also be designated nonattainment if it

c ontributes to a violation in a nearby area. Each county without a violating monitor that is8 located near a county with a violating monitor has been evaluated based on the weight of
evidence of the five factors and other relevant information to determine w hether it contributes to the nearby violation

.



### Factor 2: Emissions and Emissions

- Related Data

EPA evaluated emissions of ozone precursors ( NO
x and VOC ) and other emissions

- related data that provide information on areas contributing to violating monitors.

Emissions Data

EPA evaluated county

- level emission data for NO
x and VOC derived from the 200 8 National Emissions Inventory (NEI), version 1.5

. This is the most recently available NEI. (See http://www.epa.gov/ttn/chief/net/2008inventory.html ) Significant emissions levels in a nearby area indicate the potential for the area to contribute to observed violations. We will also consider any additional information we receive on changes to emissions levels that are not reflected in recent inventories. These changes include emissions reductions due to permanent and enforceable emissions controls that will be in place before final designations are issued and
emissions increases due to new sources.

Table 3 shows emissions of NO
x and VOC (given in tons per year) for counties in the area of analysis.

Table 3. Total 2008 NO
x and VOC Emissions.

County State Recommended
Nonattainment? NO

x (tpy) VOC (tpy) Atlantic, NJ Yes 6,143 10,713 Berks, PA Yes, other area 18,908 15,918 Bucks, PA Yes 17,736 21,160 Burlington, NJ Yes 10,919 12,909 Camden, NJ Yes 12,725 10,731 Cape May, NJ Yes 6,407 7,774 Cecil, MD Yes 4,763 3,715 Chester, PA No 16,806 16,351 Cumberland, NJ Yes 4,916 5,727 Delaware, PA No 28,118 15,881 Gloucester, NJ Yes 18,335 11,756
Kent, DE No 7,667 5,381
Mercer, NJ Yes 9,909 8,160 Montgomery, PA Yes 22,741 26,372 New Castle, DE Yes, other area 22,633 14,133
Ocean, NJ Yes 9,909 19,572 Philadelphia, PA Yes 33,176 32,021 Salem, NJ Yes 6,106 3,308
Sussex, DE Yes, other area 14,870 9,9729 Philadelphia County, PA has the highest NOx and VOC emissions in the area of analysis. Other
counties with comparat ively high emissions are New Castle County in Delaware ; Delaware and Montgomery Counties in Pennsylvania and Ocean and Burlington Counties in New Jersey.
Counties with comparatively low emissions are Kent County, Delaware ; Cecil County, Maryland ; and Salem County in New Jersey

.

P opulation density and degree of urbanization

EPA evaluated the population and vehicle use characteristics and trends of the area as indicators of the probable location and magnitude of non

- point source emissions . These include ozone

creating emissions from on

- road and off

- road vehi cles and engines, consumer products, residential fuel combustion, and consumer services. Areas of dense population or commercial development are an indicator of area source and mobile source NO
x and VOC emissions that may contribute to ozone formation

. T able 4 shows the population, population density, and population growth information for each county in the area.

Table 4 . Population and Growth.

County State
Recommended
Nonattainment? 2010 Population 2010 Population Density (1000

pop/sq mi) Absolute change in population (2000

- 2010) Population % change (2000

- 2010)
Atlantic, NJ Yes 274,549 0.45 21,569 +9%
Berks, PA Yes, other area 411,442 0.48 36,945 +10%
Bucks, PA Yes 625,249 1.01 25,841 +4% Burlington, NJ Yes 448,734 0.55 24,255 +6%
Camden, NJ Yes 513,657 2.26 6,064 +1% Cape May, NJ Yes 97,265 0.34 (5,043)

- 5%
Cecil, MD Yes 101,108 0.27 14,643 +17%
Chester, PA No 498,886 0.66 63,107 +14%
Cumberland, NJ Yes 156,898 0.31 10,547 +7%
Delaware, PA No 558,979 2.93 6,938 +1%
Gloucester, NJ Yes 288,288 0.86 31,962 +12%
Kent, DE No 162,310 0.27 35,200 +28%
Mercer, NJ Yes 366,513 1.60 14,979 +4% Montgomery, PA Yes 799,874 1.64 48,936 +7%
New Castle, DE Yes, other area 538,479 1.11 36,620 +7%
Ocean, NJ Yes 576,567 0.76 62,913 +12% Philadelphia, PA Yes 1,526,006 10.71 12,194 +1%
Salem, NJ Yes 66,083 0.19 1,867 +3%
Sussex, DE Yes, other area 197,145 0.20 39,710 +25% Sources: U.S. Census Bureau population estimates for 2010 as of August 4, 2011. ( http://factfinder2.census.gov/faces/tableservices/jsf/pages/productview.xhtml?pid=DEC_10_PL _GCTPL2.STO5&prodType=tab le )10 Philadelphia County, Pennsylvania has the highest population and population density in the area of analysis. Bucks, Chester, Montgomery, and Delaware Counties, in Pennsylvania; New Castle County in De laware; and Ocean County in New Jersey also have comparatively large populations compared to Kent County, Delaware and Salem County in New Jersey with comparatively small populations and population densities. Most counties in the analysis have experienced some population growth.

Traffic and commuting patterns

EPA evaluated the total Vehicle Miles Traveled (VMT) for each county in the area . In combination with the population/population density data and the location of main transportation arteries (see Figure 1, above), this information helps identify the probable location of non

- point
source emissions. A county with high VMT is generally a n integral part of an urban area and indicates the presence of motor vehicle emissions that may contribute to ozone formation. Rapid population or VMT growth in a county on the urban perimeter signifies increasing integration with the core urban area, and indicates that the associated area source and mobile source emissions may be appropriate to include in the nonattainment area. Table 5 shows total 2008
VMT for each county.

Table 5 . Traffic (VMT) Data

.

County State Recommended
Nonattainment? 2008 VMT* ( million miles)

Atlantic, NJ Yes 2,863
Berks, PA Yes, other area 3,335
Bucks, PA Yes 5,021
Burlington, NJ Yes 4,524
Camden, NJ Yes 3,923
Cape May, NJ Yes 1,040
Cecil, MD Yes 1,350
Chester, PA No 4,410
Cumberland, NJ Yes 1,163
Delaware, PA No 3,782
Gloucester, NJ Yes 2,645

Kent, DE No 1,565

Mercer, NJ Yes 3,306
Montgomery, PA Yes 6,883
New Castle, DE Yes, other area 5,266 Ocean, NJ Yes 3,834 Philadelphia, PA Yes 5,955
Salem, NJ Yes 992
Sussex, DE Yes, other area 2,122 * MOBILE model VMT are those inputs into the NEI version 1.5.11 New Castle County, Delaware; and Bucks, Montgomery, and Philadelphia Counties in Pennsylvania; and Burlington County in New Jersey have the highest VMT in the area of analysis. Kent County, Delaware; Cecil County, Maryland; and several counties in New Jersey have relatively low VMT.

Ta ble 6. County to County Worker Flow.

Residence County Kent,
DE New Castle,
DE Sussex,
DE Cecil,
MD Berks,
PA Bucks,
PA Chester,
PA Delaware,
PA Montgomery,
PA Philadelphia,
PA Workplace County Kent, DE 47,455 3,927 5,704 186 157 18 131 112 41 65 New Castle, DE 6,058 209,742 1,119 14,059 493 12,976 9,002 1,201 1,856 Sussex, DE 3,779 319 52,073 33 29 15 6 39 Cecil, MD 243 3,379 42 18,446 18 557 192 52 Atlantic, NJ 11 142 31 4 172 73 231 181 831 Burlington, NJ 40 475 25 27 40 4,250 426 1,306 1,559 5,087 Camden, NJ 55 434 10 72 27 2,039 539 2,287 1,844 7,196 Cape May, NJ 27 20 13 54 81 118 95 324 Cumberland, NJ 26 164 5 19 42 24 103 66 140 Gloucester, NJ 750 19 82 16 362 411 1,251 405 1,502 Mercer, NJ 10 78 12 7 37 20,812 222 345 1,298 1,676 Ocean, NJ 13 30 8 5 220 23 10 13 86 Salem, NJ 32 1,841 11 139 37 155 245 59 84 Berks, PA 4 48 5 140,819 410 1,916 187 4,231 243 Bucks, PA 12 261 12 22 675 168,090 1,133 2,060 23,722 23,248 Chester, PA 37 4,738 33 941 5,596 3,036 137,678 18,504 25,006 7,810 Delaware, PA 125 8,150 61 373 505 2,754 17,870 137,988 11,758 21,802 Montgomery, PA 27 1,851 53 176 12,727 48,414 25,673 28,144 245,619 59,970 Philadelphia, PA 83 5,386 131 254 702 31,892 10,568 48,151 54,576 429,667 Source: US Census Bureau County

- To

- County Worker Flow Files http://www.census.gov/population/www/cen2000/commuting/index.html

Bucks, Chester, Delaware, Montgomery, and Philadelphia Counties in Pennsylvania have the highest numbers of commuters to other counties in the Philadelphia

- Camden

- Vineland PA

- NJ

MD

- DE CSA

. New Castle County, Delaware, Cecil County, Maryland, and Berks County, Pennsylva nia have moderate numbers of commuters into other counties in the CSA. Sussex and Kent Counties in Delaware, which are not in the Philadelphia

- Camden

- Vineland PA

- NJ

- MD

- DE CSA, have the fewest commuters into the CSA

. More about Ocean and Mercer Counties i n Appendix A.



### Factor 3: Meteorology (weather/transport patterns)

EPA evaluate d available meteorological data , consisting of 30

- year average s ummertime w ind
d irections from the National Weather Service

, and trajectories on high ozone days to help determine how meteorological conditions, such as weather, transport patterns and stagnation conditions, would affect the fate and transport of precursor emissions contributing to ozone
formation.

The highest ozone design values, over 80 ppb, are in Bucks and Philadelphia Counties, in12 Pennsylvania, and Ocean County in New Jersey. Buck s County had the highest 2010 DV in the Philadelphia area, while Philadelphia County has the highest 2011 DV. Wind rose and trajectory analyses for Bucks and Philade lphia Counties provide data on the influence of weather on the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD nonattainment area in general. An analysis for Ocean County, the third highest site, is in Appendix A, where the wind and trajectories analyse s are used to determine if Ocean (and nearby Mercer) Counties are better suited to be in the Philadelphia

- Wilmington

- Atlantic City area or the New York

– Northern New Jersey

- Long Island area.

The NWS 30

- year average summertime wind directions are shown in Figure 2 for both Bucks and Philadelphia Counties. As can be seen from Figure 2, the winds during the ozone season come predominantly from the southwest. This indicates that emissions from Chester and Delaware Counties in Pennsylvania; New Castle County , Delaware; Cecil County, Maryland; and counties in southwest New Jersey contribute to the downwind violations in Bucks

, Philadelphia and Ocean Counties during most of the ozone season. Considering prevailing wind patterns and the location of the highest violating monitors, Berks County, Pennsylvania and Kent and Sussex Counties in Delaware are less likely to contribute to downwind violations dur ing most of the ozone season, and Ocean and Mercer are more likely to be affected by emissions in
the core of the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD area than the core of the New York City area.

This is supported by two more detailed analy ses for wind flows affecting monitors in Philadelphia and Bucks Counties (below) and Ocean and Mercer Counties (in Appendix A).

Detailed Analysis of Meteorological Transport Conditions for the Philadelphia
Nonattainment Area

Figure 1 . 30

- Year Average Su mmertime Wind Directions in the Philadelphia Area13 To further understand the meteorological transport conditions within the area around the Philadelphia area , we also evaluated 24

- hour back trajectories for the 2007

- 2011 time period, using the National Oceanic and Atmospheric Administration (NOAA) Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. The model uses the monitoring location as a starting point, and goes back in time using meteorological data to determine how a parcel of air would have traveled on a given day. EPA evaluated three separate elevations for each exceedance day to better characterize the wind pattern and pollution transport to the monitor.
EPA used monitor 42

- 101

- 0024 in Bucks County as the starting point for the HYSPLIT back trajectories, as it currently has the highest DV in the Philadelphia

- Wilmington

- Atlantic City, PA

NJ

- DE

- MD area

. The air quality monitoring data and HYSPLIT results for those exceedance days are available in the docket for this action.

Table 1 . 2007 to 2011 Exceedance

- Day 8

- Hour Ozone Values at Monitor 42

- 101

- 0024

Exceedance Day 8

- hour

average (ppm ozone) Exceedance Day 8

- hour

average (p pm ozone ) Exceedance Day 8

- hour

average (ppm ozone )

5/29/2006 0.077 7/28/2007 0.079 6/26/2010 0.084

5/30/2006 0.086 8/2/2007 0.104 7/5/2010 0.082

6/1/2006 0.084 8/3/2007 0.082 7/6/2010 0.084

6/17/2006 0.082 8/4/2007 0.08 7/7/2010 0.077

6/18/2006 0.096 8/17/2007 0.079 7/16/2010 0.08

6/19/2006 0.077 8/29/2007 0.077 7/19/2010 0.076

6/22/2006 0.081 8/30/2007 0.087 7/23/2010 0.088

7/11/2006 0.078 9/21/2007 0.083 7/28/2010 0.076

7/17/2006 0.085 4/19/2008 0.087 8/10/2010 0.088

7/18/2006 0.087 6/7/2008 0.079 8/19/2010 0.094

7/19/2006 0.077 6/10/2008 0.099 8/20/2010 0.062

7/31/2006 0.079 6/13/2008 0.08 8/29/2010 0.076

8/1/2006 0.08 6/14/2008 0.082 8/30/2010 0.079

8/2/2006 0.077 6/21/2008 0.079 9/1/2010 0.092

8/3/2006 0.077 7/3/2008 0.083 9/22/2010 0.079

8/6/2006 0.077 7/11/2008 0.082 6/1/2011 0.094

5/15/2007 0.076 7/12/2008 0.077 6/7/2011 0.089

5/25/2007 0.084 7/17/2008 0.078 6/8/2011 0.092

5/27/2007 0.087 7/18/2008 0.088 6/9/2011 0.093

5/30/2007 0.076 7/22/2008 0.085 6/10/2011 0.081

5/31/2007 0.095 7/29/2008 0.08 7/6/2011 0.076

6/1/2007 0.079 7/30/2008 0.087 7/7/2011 0.082

6/8/2007 0.097 9/4/2008 0.079 7/10/2011 0.077

6/19/2007 0.087 8/15/2009 0.084 7/18/2011 0.087

6/26/2007 0.095 5/1/2010 0.078 7/21/2011 0.085

7/9/2007 0.106 6/2/2010 0.08 7/22/2011 0.08614 Exceedance Day 8

- hour

average (ppm ozone) Exceedance Day 8

- hour

average (p pm ozone ) Exceedance Day 8

- hour

average (ppm ozone )

7/14/2007 0.076 6/4/2010 0.079 7/29/2011 0.079

7/15/2007 0.076 6/19/2010 0.078

7/17/2007 0.081 6/22/2010 0.082

F igure 2 overlays HYSPLIT 24

- hour back trajectories for all the 2007

- 2011 ozone exceedances

at monitor 42

- 101

- 0024 on a Google Earth map of the northeastern United States. It gives an overview of long

- range transport to the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD

a re a. As seen in Figure 2 , the 24

- hour back trajectories indicate regional transport from many
directions and over several states.

Figure 2 . NOAA HYSPLIT 24

- Hour Back Trajectories for 2007

- 2011 Exceedances Days

- Overview

I n Figure 3 , bel ow, these EPA has zoomed in on these same 24

- hour HYSPLIT back trajectories, showing more of the nearby transport on high ozone days. This zoomed in perspective shows that on exceedance days, winds are predominantly from the south and southwest. This cor relates15 reasonably well with the NWS 30

- year average wind directly given above, which gave prevailing
winds as from the west

- southwes t and south

- southwest. Figure 3 also shows a large percent of exceedance days with winds coming from the northwest, and several exceedance days with winds coming from the east.

Figure 3 . NOAA HYSPLIT 24

- Hour Back Trajectories for 2006

- 2010 Exceedances Days

- Zoom View

To further illustrate the local transport situation in the Philadelphia

- Wilmington

- Atlantic City,
PA

- N J

- DE

- MD a rea, EPA has selected specific trajectories for two “ozone episodes,” periods when the ozone levels are high for several consec utive days. As shown in Table 1 , the 8

- hour average ozone value at monitor 42

- 101

- 0024 was above the standard for three days in a row in 2011 (June 7

- 9) and 2007 (May 30

- J une 1). Figure 4 shows that at the start of the 2011 episode, winds came from the predominant southwesterly direction. Figures 5 and 6 show that during the second and third days of the 2011 episode, win s were mainly from the west. Figures 7 through 9 depict the HYSPLIT back trajectories for the 2007 episode. These figures show that the while
winds can start out northwest of at monitor 42

- 101

- 0024, throughout most of the 2007 episode
winds were from the southwest.16 Figures 4

, 5 & 6

, NOAA HYSPLIT 24

- Hour Back Trajectories June 7

- 9, 201117 Figures 7

, 8, & 9 NOAA HYSPLIT 24

- Hour Back Trajectories May 30

- June 1, 200718 

### Factor 4: Geography/topography (mountain ranges or other air basin boundaries)

The geography/topography analysis evaluates the physical features of the land that might affect the airshed and, therefore, the distribution of ozone over the area

.

The Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD a rea does not have any geographical or topographical barriers significantly limiting air pollution transport within its air shed. Therefore, there are no barriers to contribution from upwind areas.



### Factor 5: Jurisdictional boundaries

EPA consider s existing jurisdictional boundaries for the purposes of providing a clearly defined legal boundary and so that areas designated nonattainment have the legal authority and cooperative planning necessary to carrying out the air quality planning and enforceme nt functions for nonattainment areas. Examples of jurisdictional boundaries include existing/prior
nonattainment areas for ozone or other urban

- scale pollutants, counties, air districts, townships, metropolitan planning organizations, state lines, urban g rowth boundary, etc. Where existing jurisdictional boundaries are not adequate to describe the nonattainment area, other clearly defined and permanent landmarks or geographic c oordinates are used.

T he major jurisdictional boundaries in the Philadelphia

- W ilmington

- Atlantic City, PA

- NJ

- DE

MD area are the state lines between Pennsylvania, Delaware, and New Jersey. A ir

- quality
monitors that violate the 2008 8

- hour ozone NAAQS in the Philadelphia Area are located in Delaware, Maryland, New Jersey, and Pennsyl vania.

The Philadelphia

- Camden

- Vineland CSA consists of New Castl e County, Delaware; Cecil County, Maryland; Burlington

, Camden

, Cumberland, Gloucester, and Salem Counties in New Jersey, and Berks, Bucks , Chester, Delaware, Montgomery, and Philadelphia Counties in Pennsylvania. All those counties, except for Berks County, Pennsylvania are included in the Philadelphia

- Wilmington

- Atlantic City nonattainment area for the 1997 8

- hour ozone NAAQS.
The nonattainment area also includes Kent and Sussex Countie s, Delaware and Atlan tic, Cape May, Mercer, and Ocean Counties, New Jersey.

Mercer and Ocean Counties, New Jersey are part of the New York

- Newark

- Bridgeport, NY

- NJ

CT

- PA CSA. Atlantic County makes up the Atlantic City

- Hammonton, NJ MSA. Cape May County makes up the Ocean City, NJ MSA

. In Delaware, Kent County, Delaware makes up the
Dover MSA a nd Sussex County makes up the Seaford Micropolitan Statistical Area.

T he Delaware Valley Regional Planning Commission (DVRPC)

, the metropolitan planning organization (MPO) in the Philadelphia Area, serves Bucks, Chester, Delaware, Montgomery

, and Philad elphia Counties in Pennsylvania, and Burlington, Camden, Gloucester

, and Mercer Counties in New Jersey. New Castle County, DE and Cecil County, Maryland are in a separate MPO, the Wilmington Area Planning Council (WILMAPCO)

.19 Delaware New Castle County has historically been part of the Philadelphia

- Wilmington

- Atlantic City, PA

NJ

- DE

- MD nonattainment area for ozone (1

- hour and 8

- hour) and fine p articulate matter (PM 2.5 ). New Castle County is part of the Wilmington, DE

- MD

- NJ Metropolitan Division of
the Philadelphia

- Camden

- Wilmington Metropolitan Statistical Area ( MSA ) in the Philadelphia

Camden

- Vineland CSA

. Being part of a statistical area indicates that counties are linked through employment and commuting. According to the Office of Management and Budget’s “ Standards for Defining Metropolitan and Micropolitan Statistical Areas,” published in the Federal Register

on December 27, 2000 (65 F R 82228) , the “general concept of a Metropolitan Statistical Area or a Micropolitan Statistical Area is that of an area containing a recognized population nucleus and adjacent communities that have a high degree of integration with that nucleus.” D elaware

, Pennsylvania, Maryland and New Jersey have a long history of working cooperatively through
the Ozone Transport Commission ( OT C) and the Mid

- Atlantic Northeast Visibility Union (MANE

- VU) with ozone attainment planning. Furthermore, the two local MPOs, DV RPC and
WILMAPCO , have worked together for decades.

Kent and Sussex Counties are less connected to the Philadelphia

- Wilmington

- Atlantic City, PA

NJ

- DE

- MD area. They are not part of the Philadelphia

- Camden

- Vineland CSA . Kent County makes up the Dover MSA, and Sussex County makes up the Seaford Micropolitan Statistical
Area. The Dover/Kent County MPO is the planning organization for Kent County, Delaware. This MPO covers 20 municipalities including all of Smyrna, whic h is also in New Castle County and all of Milford, which is also in Sussex County. Planning for Sussex County is done by the Sussex County Planning and Zoning Commission While Kent County was part of the Philadelphia

- Wilmington

- Trenton nonattainment area for the 1

- hour ozone NAAQS, Sussex County was a separate nonattainment area.

Maryland Cecil County has historically been part of the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

DE

- MD nonattainment area for ozo ne (1

- hour and 8

- hour) and PM 2.5

. Cecil C ounty is part of
the Wilmington, DE

- MD

- NJ Metropolitan Division of the Philadelphia

- Camden

- Wilmington MSA in the Philadelphia

- Camden

- Vineland CSA

. Maryland, D elaware, Pennsylvania, and New Jersey have a long history of working cooperatively through the OT C and MANE

- VU and with ozone attainment planning. Furthermore, the two local MPOs, DVRPC and WILMAPCO , have worked together for decades.

Pennsylvania Bucks, Chester, Delaware, Montgomery, and Philadelphia Counties have historically been part
of the Phi ladelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD nonattainment area for ozone (1

- hour and 8

- hour) and PM 2.5

. These five counties are part of the Philadelphia, PA Metropolitan
Division of the Philadelphia

- Camden

- Wilmington MSA in the Philadelphia

- Camden

- Vi neland
CSA

. These counties are part of DVRPC, the main MPO for the Philadelphia Area.

Berks County is less connected to the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD
nonattainment area . While it was added to the Philadelphia

- Camden

- Vineland CSA in December 2005, it’s in a separate MSA, the Reading, PA MSA. Berks County has historically not been part of the Philadelphia nonattainment area for 8

- hour ozone and PM 2.5 , but has been designated separately as the Reading area. Berks County was design ated20 attainment/unclassifiable for 1

- hour ozone. In addition, Berks County is covered by a separate MPO, the Berks County Planning Commission.

See Appendix B for EPA’s response to comments on the boundaries of the Philadelphia

Wilmington

- Atlantic City, P A

- NJ

- DE

- MD area in Pennsylvania.

New Jersey

Southern New Jersey, from Mercer and Ocean Counties southward, are part of the Philadelphia

Wilmington

- Atlantic City, PA

- NJ

- DE

- MD ozone nonattainment area since EPA’s previous eight

- hour ozone standard designations in 2004, which were upheld by the US Court. Ocean County is part of the NYC transportation planning area and Mercer County is part of the Philadelphia planning area. We note that New Jersey’s desire to continue to include Ocean and
Mercer Counties in the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD area is important to this factor, since New Jersey has to balance inconveniences due to transportation planning

areas t hat are differe nt from the nonattainment areas with benefits of including Ocean and Mercer Counties in the Philadelphia nonattainment area.

New Jersey also requested that EPA designate all of the counties from New Jersey that were designated as nonattainment for Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD area for the 2008 ozone standard be designated as nonattainment for the 2011 ozone standard, even those counties that are not in the Philadelphia

- Canden

- Vineland CSA.



### Conclusion

Based on the assessment of factors described above, and with additional details in the enclosed Appendices, EPA concluded that the following counties meet the CAA criteria for inclusion in
the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD nonattainment area for the 2008 eight

- hour ozone standard : New Castle County, Delaware; Cecil County, Maryland; Atlan tic, Burlington, Camden, Cape May, Cumberland, Gl oucester, Mercer, Ocean, and Salem Counties in New Jersey; and Bucks, Chester, Delaware, Montgomery, and Philadelphia Counties in Pennsylvania. The Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD nonattainment area
for the 1997 8

- hour ozone NAAQS includ ed these same counties, plus Kent and Sussex Counties
in Delaware.

New Castle Count y in Delaware ; Cecil County in M aryland; Berks, Bucks , Montgomery and Philadelphia Counties in Pennsylvania and Camden, Cumberland, Gloucester, Mercer and Ocean
Counties in New Jersey show violations of the 2008 ozone NAAQS based on 2010 design values. Maryland and Pennsylvania have requested that these violating counties in their respective States be included as part of the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

MD nonattainment area, which is consistent with their inclusion of that area for the 1

- hour and
1997 8

- hour NAAQS and the PM2.5 NAAQS. New Jersey requested that its violating counties
listed above be included in the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD area, as21 they were for the 1997 8

- hour NAAQS. The factors above support inclusion of these counties and neighboring counties recommended by the states in that nonattainment area. Therefore, we will include them as part of the Philadelphia

- Wilm ington

- Atlantic City, PA

- NJ

- DE

- MD nonattainment area for the 2008 ozone NAAQS.

We have made a further analysis of the other counties in the area that Delaware and Pennsylvania did not include in their request for the Philadelphia

- Wilmington

- Atlantic Cit y, PA

NJ

- DE

- MD nonattainment area, as well as further analysis of New Jersey’s request for Ocean
and Mercer Counties to be included in the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

MD area, summarized as follows.

New Castle County, Delaware has rela tively high emissions, high population, and high VMT. Considering prevailing winds from the southwest, this county likely contributes to downwind violations of the ozone NAAQS in the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD
Area

. Furthermore, N ew Castle County is part of the Philadelphia

- Wilmington

- Atlantic City 8

- hour ozone nonattainment area for the 1997 ozone standard and the Philadelphia

- Camden

Vineland CSA. New Castle County has a moderate degree of commuting into the other counties
in the CSA, including over 24,000 commuters into Cecil, Chester, Delaware, Montgomery, and Philadelphia Counties. Therefore, EPA will designate New Castle County as nonattainment as part of the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD Area.

Chester a nd Delaware Counties in Pennsylvania are part of the Philadelphia, PA Metropolitan Division of the Philadelphia

- Camden

- Wilmington MSA in the Philadelphia

- Camden

- Vineland
CSA. These counties have been historically part of the Philadelphia

- Wilmington

- Atlant ic City,
PA

- NJ

- DE

- MD nonattainment areas for ozone (8

- hour and 1

- hour) and PM 2.5 and are linked together with significant commuting throughout the 5 counties. These counties have relatively high populations and population densities. Delaware County has t he second highest NOx emissions in the areas of analysis and among the highest VOC emissions. Taking into account
the prevailing winds during the ozone season are predominantly from the south west, emissions from Chester and Delaware Counties likely contrib ute to downwind violations in Bucks and Philadelphia Counties during most of the ozone season. Considering all these factors, EPA has
concluded that Chester and Delaware Counties are included in the Philadelphia

- Wilmington

Atlantic City, PA

- NJ

- DE

- MD area.

In addition, monitors in Sussex County, Delaware and Berks County, Pennsylvania show violations of the 2008 ozone NAAQS and must be designated nonattainment. We believe that Sussex County, Delaware and Berks County, Pennsylvania should be designated as in separate nonattainment areas, and explained below.

Berks County, Pennsylvania has a violating monitor, but relatively moderate emissions, population, and VMT. There is some commuting from Berks County to the other counties in the Philadelphia Area, and Berks County is part of the Philadelphia

- Camden

- Vineland CSA. However, Berks C ounty has historically been a separate ozone and PM2.5 nonattainment area. The County’s MPO, the Berks County Planning Commission, is separate from the Philadelphia Area’s MPO, DVRPC. Furthermore, meteorology indicates that on typical summer days when
th e violating monitors are experiencing exceedances of the ozone NAAQS, emissions from22 Berks County are not upwind of those monitors in the Philadelphia

- Wilmington

- Atlantic City,
PA

- NJ

- DE

- MD Area and thus we believe emissions from Berks County do not signifi cantly contribute to nonattainment at those monitors. Therefore, EPA has concluded that Berks County
should not be included in the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD Area, and should be designated as nonattainment in a separate area 4

.

Sussex County, Delaware has a monitor that is violating the 2008 ozone NAAQS. It has
moderate emissions and population in the area as compared with the other counties in the area of analysis. It is not part of the Philadelphia

- Camden

- Vineland CSA. Furth ermore, c onsidering prevailing winds from the southwest and the location of the highest violating monitors in the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD Area, it is not likely that Sussex County is contributing significantly to the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD area. Therefore, EPA has concluded that Sussex County should not be included in the Philadelphia

Wilmington

- Atlantic City, PA

- NJ

- DE

- MD area, and should be designated as nonattainment in a separate area 5

.

Kent County , Delaware has a monitor that meets the 2008 8

- hour ozone NAAQS. This county has comparatively low emissions, population and VMT, and is not part of the Philadelphia

Camden

- Vineland CSA. Therefore, EPA has concluded that Kent County should not be
include d in the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD area, and should be designated as unclassifiable/attainment.

Ocean and Mercer Counties are more affected by emissions from counties in the Philadelphia metropolitan area than emissions from count ies in the New York City metropolitan area and EPA
concludes that Ocean and Mercer Counties should be included in the Philadelphia

- Wilmington

Atlantic City, PA

- NJ

- DE

- MD a rea, as they were for the 1997 8

- hour ozone NAAQS.

New Jersey requested all of the co unties in the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

DE

- MD nonattainment area for the 1997 ozone NAAQS designations should be included in the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD nonattainment area for the 2008 ozone NAAQS designations. As noted in the beginning of this TSD, the issue placing Ocean and
Mercer Counties in the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD area when they are in the New York CSA is decided on the basis of the factor analysis. However, the other counties recommended by New Jersey for inclusion in the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD area that were in the Philadelphia

- Wilmin gton

- Atlantic City, PA

- NJ

- DE

MD area for the 1997 ozone NAAQS designations are approved by EPA, since New Jersey’s
counties that are outside the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD CSA are not in a metropolitan area shared by another state. Thus, EPA concurs with New Jersey’s
recommendation for Atlan tic, Burlington, Camden, Cape May, Cumberland, Gloucester,
and Salem Counties to be included in the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

MD nonattainment area for the 2008 ozone NAAQS.

4 See EPA’s Technic al Analysis for the Reading Area, sent to the Commonwealth of Pennsylvania by EPA Region
III.

5 See EPA’s Technical Analysis for the Seaford Area, sent to the State of Delaware by EPA Region III.23 

### Appendix A. Factor Analysis for New Jersey’s Request to Include Ocean and Mercer Counties in the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD Nonattainment Area

New Jersey proposes that the entire state be designated as nonattainment for the 2 008 ozone NAAQS 6 , but requested that the boundary between the New York City nonattainment area and Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- DE

- MD (Philadelphia nonattainment area) be
different from the CSA boundaries.

EPA has determined that severa l factors are relevant to determining if the boundaries of the New York City and Philadelphia areas proposed by the State of New Jersey are approvable. The following sections provide additional information, as available and relevant.



### Factor 1: Air Quality Data

Air quality data is based on the 8

- hour o zone design values (in pp b ) for air quality monitors in New Jersey, based on data for the 2008

- 2010 period (i.e., the 2010 design value, or DV). These

are the most recent years with fully

- certified air quality data

. A monitor’s DV is the metric or
statistic that indicates whether that monitor attains a specified air quality standard. The 2008

o zone NAAQS are met when the annual f ourth

- highest daily maximum 8

- hour average
concentrati on, averaged over 3 years is 0.075 ppm (75ppb) or less

. A DV is only valid if minimum data completeness criteria are met. See 40 CFR part 50 App endix P . Where several monitors are located in a county (or a designated nonattainment area or maintenance ar ea ), the
DV for the county or area is determined by the monitor with the highest level.

The 2010 DVs for the ozone NAAQS for counties New Jersey are in Table 2.

Table 2 . Air Quality Data

.

County State Recommended
Nonattainment? 2010 8

- hour Ozone
DV (ppb)
Atlantic, NJ Yes 74
Berks, PA Yes, other area 79
Bucks, PA Yes 83 Burlington, NJ Yes

-- Camden, NJ Yes 80 Cape May, NJ Yes

-- Cecil, MD Yes 80
Chester, PA No 76
Cumberland, NJ Yes 76

6 New Jersey (as well as Maryland, Delaware and Connecticut ) requested a large, regional nonattainment area, with local designations if EPA did not approve the larger area designation. See EPA’s separate response to the states, elsewhere in these Technical Support Documents.24 Delaware, PA No 74
Gloucester, NJ Yes 81
Kent, DE No 74
Mercer, NJ Yes 78 Montgomery, PA Yes 78
New Castle, DE Yes, other area 76
Ocean, NJ Yes 81 Philadelphia, PA Yes 82
Salem, NJ Yes

-- Sussex, DE Yes, other area 77

Note: Counties with no ozone monitor are identified with “

-- “ in the 2010 8

- hour Ozone DV column

The highest design value in NJ is 81ppb in Ocean and Gloucester Counties. The highest design value in the Philadelphia nonattainment area is 83ppb in Bucks Co., PA. The highest design value in the New York City nonattainment area is 84 ppb in Suffolk County, Long Island, NY

. The elevated design values in Ocean County is a reason for including Ocean in the Philadelphia

Wilmington

- Atlantic City nonattainment area, as other factors show its ozone is mostly from Philadelphia, not New York.

The air quality monitoring data are included in the docket for this action

.

As shown in Figures 1 and 2, design values decrease further north and east from Ocean County, until the next set of peak design values occur downwind of New York City on Long Isl and and in Connecticut. This is an indication that Ocean County is affected strongly and mostly by sources to the south and west, which includes the Philadelphia area. This is typical of the northeastern United States, since most of peak ozone design val ues are found north and east of the centers of major urban areas.



### Factor 2: Emissions and Emissions

- Related Data

This factor does not provide much information related to New Jersey’s request for Ocean and Mercer Counties to be included in the prospectiv e Philadelphia nonattainment area.

Emissions Data

Not evaluated because New Jersey has proposed that every county in New Jersey is proposed to
be nonattainment. There are no counties proposed to be attainment in New Jersey.

The only issue, whether Mer cer and Ocean Counties should continue to be included with the Philadelphia area as opposed to the New York area, does not use this factor as a deciding factor. The question that needs a multi

- factor analysis is about whose emissions affect Ocean and
Merc er Counties the most, which is best determined by analysis of transport of ozone and ozone

forming emissions.25 Population density and degree of urbanization

Not evaluated since the question is the impact of urban ozone on Ocean and Mercer County and
less so about whether Ocean and Mercer Counties affect other areas.

Traffic and commuting patterns

EPA evaluated the commuting patterns of residents in the are a

. A neighboring county with high
VMT and/or a high num b er of commuters coming into the county with a violating monitor is generally an integral part of an urban area and indicates the presence of motor vehicle emissions that may contribute to ozone forma tion. Rapid population or VMT growth in a county on the urban perimeter signifies increasing integration with the core urban area, and indicates that the
associated area source and mobile source emissions may be appropriate to include in the
nonattainment area. The attached spreadsheet shows traffic and commuting pattern data, including total 2008 VMT* and 10

- year VMT growth, number of commuters in each county who drive to another county within the area , the percent of total commuters in each county who

co mmute to other counties within the area ** , and the total vehicle miles traveled (VMT) for each county.

* MOBILE model VMTs are those inputs into the NEI version 1.5. ** U.S. Census Bureau estimates for 2000 County

- to

- County Worker Flow http://www.census.gov/hhes/commuting/data/commuting.html

.

The County

- to

- County Worker Flow data from 2000 was used in the previous 2004 analysis for
the 1997 ozone standard.

Based on 2000 data, t he 2004 analysis noted that more commuters either stay in Ocean County
or Mercer Counties or go to the Philadelphia area than go to the New York City area

.

The data are included in the docket for this action

.

Commuting from Ocean and Merce r Counties into central Philadelphia is much lower than the counties with the highest numbers of commuters heading into Philadelphia. For Ocean County, most of the top

- ranked counties for its commuters are in the New York

- Newark

- Bridgeport, NY

NJ

- CT

- PA CS A. Mercer County’s second

- ranked destination is New York County (Manhattan). However, the reason for including Ocean and Mercer Counties in the Philadelphia

- Wilimington

Atlantic City nonattanment area is due to the impact that the Philadelphia area has o n Ocean and Mercer Counties, not their impact on Philadelphia. 

### Factor 3: Meteorology (weather/transport patterns)

EPA evaluate d available meteorological data to help determine how meteorological conditions, such as weather, transport patterns and stagnation conditions, would affect the fate and transport of precursor emissions contributing to ozone formation.26 Wind rose for 1988

- 1992

. Figure 3

- 1. Daytime wind rose during ozone season, Philadelphia, PA.

The 1997 designation assessment showed, via wind roses (see above), trajectory analysis and contribution assessments, that Ocean County (and by extension, Mercer County) are downwind

o f the Philadelphia metropolitan area and are not as strongly affected by emissions from the New York City metropolitan area. More recent trajectory analyses continue to support New Jersey’s request.

EPA produced trajectories from NOAA’s HYSPLIT program for days when monitoring sites in Mercer and Ocean Counties had the highest ozone concentrations from 2008 through 2011. Trajectories were run backwards from the monitoring site with the arrival time at the monitoring
site at 1400 local standard time. Th ree trajectories were run for each day

– starting at different
altitudes that are climatologically within the mixed layer during the afternoon, when peak ozone typically occurs and thermal mixing from sunshine is at a maximum. These trajectories predomina ntly come through eastern Pennsylvania and less frequently from southeastern New York. Thus, emissions from the Philadelphia metropolitan area are more likely to affect Ocean and Mercer Counties than the New York City metropolitan area.27 In summary, thes e trajectories show when the air comes from on high ozone days at these monitoring sites in recent years.

Figure 3

- 2. Trajectories for high ozone days at monitors in Ocean and Mercer Counties.

Figure 3

- 2, with all of the trajectories for the three moni toring sites in Ocean and Mercer Counties, is too busy to examine closely. However, it shows that the thicket of trajectories is thickest over eastern Pennsylvania, and markedly less so over New York. This is not surprising, since the basic conceptual mo del for ozone formation in the metropolises of the northeastern corridor of the United States is for ozone to form on sunny days with surface winds from the
southwest and winds aloft from the west.

Here’s the classic example of the conceptual model from the University of Maryland:28 Figure 3

- 3. Conceptual model of ozone transport

Here are composite graphics of the trajectories for each site in Ocean and Mercer Counties, as
well as for each of the three altitudes:

Figure 3

- 4. Trajectories to the ozone monitor in Ocean County, ending at 100 meters above ground level in mid

- afternoon on high ozone days.29 Figure 3

- 5. Trajectories to the ozone monitor in Ocean County, ending at 500 meters above ground level in mid

- afternoon on high ozone days.

Figure 3

- 6. Trajectories to the ozone monitor in Ocean County, ending at 1000 meters above ground level in mid

- afternoon on high ozone days.30 Figure 3

- 7. Trajectories to the Rider University ozone monitor in Mercer County, ending at 100 meters above gr ound level in mid

- afternoon on high ozone days.

Figure 3

- 8. Trajectories to the Rider University ozone monitor in Mercer County, ending at 500 meters above ground level in mid

- afternoon on high ozone days.31 Figure 3

- 9. Trajectories to the Rider Univ ersity ozone monitor in Mercer County, ending at 1000 meters above ground level in mid

- afternoon on high ozone days.

Figure 3

- 10. Trajectories to the Washington Crossing ozone monitor in Mercer County, ending at 100 meters above ground level in mid

- aft ernoon on high ozone days.32 Figure 3

- 11. Trajectories to the Washington Crossing ozone monitor in Mercer County, ending at 500 meters above ground level in mid

- afternoon on high ozone days.

Figure 3

- 12. Trajectories to the Washington Crossing ozone monitor in Mercer County, ending at 1000 meters above ground level in mid

- afternoon on high ozone days.33 The original mapping file for the trajectory analysis is included in the docket for this action.



### Factor 4: Geography/topography (mountain ranges or other air basin boundaries)

New Jersey’s division of its nonattainment areas into two areas is not based on, nor affected by, topographic barriers.



### Fa ctor 5: Jurisdictional boundaries

On ce the general areas to be included in the nonattainment area were determined, EPA
consider ed existing jurisdictional boundaries for the purposes of providing a clearly defined legal boundary and carrying out the air quality planning and enforcement functions for nonattainment

areas. Examples of jurisdictional boundaries include existing/prior nonattainment areas for
ozone or other urban

- scale pollutants, counties, air districts, townships, metropolitan planning organizations, state lines, Reservations, urban gro wth boundary, etc. Where existing jurisdictional boundaries are not adequate to describe the nonattainment area, other clearly defined and permanent landmarks or geographic c oordinates were considered.

EPA approved the inclusion of Ocean and Mercer Count ies into the Philadelphia nonattainment area for the 2004 ozone nonattainment designations.

Ocean County is in the New York City metropolitan transportation planning organization. Mercer County is in the Philadelphia metropolitan transportation plannin g organization. Since 2004, New Jersey has worked with Ocean County being within the Philadelphia nonattainment area and in the New York City

- centered transportation planning organization. If New Jersey requests that Ocean County should be included with the Philadelphia nonattainment area despite the possible difficulties of this situation, this factor should not be a reason for declining New Jersey’s request.



### Summary

EPA has determined that ozone concentrations in Mercer and Ocean Counties are more strongly affected by emissions from the Philadelphia metro area in eastern Pennsylvania than the New York City metro area in southeastern New York. Ocean and Mercer Countie s should be in the Philadelphia ozone nonattainment area as they were for designations for the previous 1997 eight

hour ozone standard.

EPA uses five types of factors when we consider how to determine the boundaries of a
nonattainment area:
1. Air quality d ata ( including the design value calculated for each FRM or FEM monitor in
the area );34 Both Ocean and Mercer Counties violate the air quality standard; with Ocean County having a higher design value than any monitors further downwind of Ocean County, except the peak monitors downwind of New York City.
2. Emissions and emissions

- related data (including location of sources and population

, amount of emissions and emissions controls , and urban growth patterns); This factor has a limited relevance to this issue, as the issue is whether the Ocean and Mercer Counties are more affected by the Philade lphia nonattainment area than the New York City area. However, one factor from the 2004 analysis noted that more commuters stay in Ocean County or go to the Philadelphia area than go to the New York City area. 7
3. Meteorology (weather/transport patterns) ; Th e 2004 analyses of the evaluation of boundaries for the 1997 ozone NAAQS 8 show that Ocean County is much more likely to be impacted by winds from the Philadelphia area than winds from the New York City area. However, more recent wind rose data and trajecto ry analyses support New Jersey’s recommendation that Mercer and Ocean County are affected more strongly by the Philadelphia area than the New York area.
4. Geography and topography (mountain ranges or other basin boundaries) ; Not much of a factor, since there are no major topographic features affecting conclusions from the wind flow analyses.
5. Jurisdictional boundaries (e.g., counties, air districts, existing nonattainment areas, Indian country , metropolitan planning organizations (MPOs)) Ocean County is part of the NYC transportation planning area and Mercer County is part of the Philadelphia planning area. However, Ocean and Mercer Counties have been in the Philadelphia nonattainment area since 2004. New Jersey’s desire to continue to
include Ocean and Mer cer Counties in the Philadelphia area prevails, since New Jersey has to deal with any inconveniences due to transportation planning areas that are different
from the nonattainment areas.

EPA received no negative comments during the comment period about t he assignment of Ocean and Mercer Counties to the Philadelphia nonattainment area.

7 This factor uses Census Bureau data from 2000, which will be updated if newer data are available.

8 http://www.epa.gov/ozonedesignations/1997standards/documents/tsd/ch3.pdf35 Appendix B: Response to Comments on Berks County and the Philadelphia
Nonattainment Area

In Pennsylvania’s February 28, 2012 response to EPA’s December 9, 2011 “120

- day letter”, the Commonwealth provided information to respond to public comments on EPA’s preliminary
recommendations. Comments were submitted to EPA, recommending that the agency include Reading (Berks County) in Philadelphia area because Reading is part of the Philadelphia

Camden

- Vineland Consolidated Statistical Area (CSA). The Commonwealth disagreed with this suggestion and supported EPA’s proposal to designate Berks County as a single county nonattainment area for the following reasons:

• The Commonwealth’s recommendation and EPA’s preliminary response are consistent with
the Of fice of Management and Budget (O MB) definition. The O MB defines the Reading metropolitan statistical area as an area that consists of on ly Berks County. Although the
O M B added Berks County to the Philadelphia CSA in 2006 because of increasing commuting ties to the larger area, Berks County traditionally has its own planning functions, including its own countywide transportation planning organization.

• EPA designated Berk s County as a single

- county nonattainment area for the 1

- hour ozone standard, the 1997 8

- hour ozone standard and the 1997 fine particulate matter standard.

• Analysis of the most current work destination data for Berks County’ indicates that in 2009, 57.7 pe rcent of the employment of Berks County residents was in Berks County.

• The Reading Air Basin, defined in 25 Pa. Code 

## § 121,1 and codified in 40 CFR 52.2020, covers portions of Berks County and no other county.

• Based on the 2008 National Emissions Inventory shown below, 

### VOC and NOx emissions (tons per year) in Berks County are low compared to emissions in the 5

- county Philadelphia Area. The five Pennsylvania counties (Bucks, Chester, Delaware, Montgomery and Philadelphia) are part of a much larger CSA, which in turn is only part of the proposed four

state Philadelphia

- Wilmington

- Atlantic City nonattainment area. Therefore, the inclusion of Berks County in the Philadelphia

- Wilmington

- Atlantic City area is unlikely to have a significant effect on the area attai ning the standard

.36 Appendix C. Ozone Design Values in Pennsylvania Calculated I ncluding 2011 Ozone Data

Pennsylvania submitted certified ozone data for 2011 to EPA in November 2011. Since no other states in the Philadelphia Area submitted certified ozone data for 2011 during EPA’s review process, EPA will not include Pennsylvania’s 2011 ozone data in calculating design values for designations . The effect of using 2011 data from Pennsylvania is listed below for information

purposes , with the 2011 des ign value being calculated with air quality data from 2009, 2010 and
2011

.

County State Recommended
Nonattainment? 2010 8

- hour Ozone DV (ppb) 2011 8

- hour Ozone DV (ppb)
Atlantic, NJ Yes 74
Berks, PA Yes, other area 79 77

Bucks, PA Yes 83 80
Burlington, NJ Yes

-- Camden, NJ Yes 80 Cape May, NJ Yes

-- Cecil, MD Yes 80
Chester, PA No 76 74

Cumberland, NJ Yes 76
Delaware, PA No 74 73

Gloucester, NJ Yes 81
Kent, DE No 74
Mercer, NJ Yes 78 Montgomery, PA Yes 78 77

New Castle, DE Yes, other area 76
Ocean, NJ Yes 81 Philadelphia, PA Yes 82 83

Salem, NJ Yes

-- Sussex, DE Yes, other area 77

Notes: Counties with no ozone monitor are identified with “

-- “ in the 2010 8

- hour Ozone DV column

. 2001 DVs are included for Pennsylvania counties because Pennsylvania submitted certified 2011 data to E P A in
November 2011.

The highest ozone design values, over 80 ppb, are in Bucks and Philadelphia Counties, in Pennsylvania, and Ocean County in New Jersey. Buck County had the h ighest 2010 DV in the Philadelphia area, while Philadelphia County has the highest 2011 DV

.37 Technical A nalysis for the Seaford Area

Figure 1 is a map of the Seaford, DE nonattainment area

. The map provides other relevant
information including the locations and design values of air quality monitors , county and other jurisdictional boundaries

. The map shows the boundaries of the Seaford Micropolitan Statistical Area (Sussex County, Delaware), the Dover Metropolitan Statistical Area (MSA) (Kent County, Delaware), the Philadelphia

- Camden

- Vineland CSA, the existing nonattainment area boundary
for the 1997 ozone NAAQS, and EPA’s nonattainment boundary for the 2008 ozone NAAQS.

Figure 1.

For purposes of the 1997 ozone NAAQS, the entire State of Delaware, including the Seaford Area, was designated nonattainment and was included in the Philadelphia

- Wilmington

- Atlantic City, PA

- NJ

- MD

- DE nonattainment area.

In March 2009, the State of Delaware recommended a large, multi

- state nonattainment area,

cov ering the entire States of Delaware, Maryland, Michigan, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Virginia, and West Virginia, and the District of Columbia. Alternatively, Delaware recommended that the entire State of Delaware be designat ed as a stand

alone nonattainment area. In October 2011, Delaware updated its recommendations. In that letter, Delaware expanded its recommended large multi

- state nonattainment area to include the States of Kentucky, Indiana, Illinois, Missouri, Tennesse e, and Wisconsin. In addition, in its38 October 2011 letter, the State of Delaware specified that if EPA did not accept either of its designation options, then Kent County should not be designated nonattainment. This
recommendation is based on 2008

- 2010 dat a and preliminary 2009

- 2011 data. The
recommendations were based on data from Federal Reference Method (FRM) monitors or Federal Equivalent Method (FEM) sited and operated in a ccordance with 40 CFR Part 58. (See the March 18, 2009 letter from Governor Jack A. Markell to EPA, received on April 3, 2009; and the October 28, 2011 letter from the Delaware Department o f Natural Resources a nd
Environmental Control

. )

After considering these recommendations and based on EPA's technical analysis described below, EPA is designating a new nonattainment area, the Seaford area, which consists of one county in Delaware

, Sussex County (identified in Table 1 below) as “nonattainment” for the 2008 ozone NAAQS

.

Table 1. State's Recommended and EPA’s Designated Nonattainment Counties for the Seaford
Area.

Seaford State

- Recommended
Nonattainment Counties EPA Designated
Nonattainment Counties
Delaware None Sussex

Factor Assessment

The area covered by this analysis is the Seaford Micropolitan Statistical Area (Sussex County, Delaware) and surrounding counties , except for Cape M ay and Cumberland Counties, New Jersey

. Based on EPA’s five

- factor analyses, EPA has determined that Cape M ay and Cumberland Counties should be designated as nonattainment in the Philade lphia

- Wilmington

Atlantic City Area for the 2008 ozone NAAQS

. See EPA’s technical analyses for the Philadelphia

- Wilmington

- Atlantic City A rea for EPA’s rationale supporting our nonattainment designation for these counties. To the extent that emissions fr om the Cape M ay and Cumberland Counties may contribute ozone concentrations in the Seaford nonattainment area, that contribution will be lessened by emission controls put in place in those separate nonattainment

areas

. Therefore, EPA is not including Cape M ay and Cumberland Counties in this analysis for
the Seaford nonattainment area.



### Factor 1: Air Quality Data

For this factor , we considered 8

- hour o zone design values (DV) (in parts per billion (ppb) ) for air quality monitors in the count y in the Seaford Area (Sussex County, Delaware) and counties in the nearby surrounding area based on data for the 2008

- 2010 period (i.e., the 2010 design value, or DV) , which are the most recent years with fully

- certified air quality data

. A monitor’s DV is
the me tric or statistic that indicates whether that monitor attains a specified air quality standard.
The 2008 o zone NAAQS are met when the annual f ourth

- highest daily maximum 8

- hour average concentration, averaged over 3 years is 0.075 ppm (75 ppb) or less

. A DV is only valid if minimum data completeness criteria are met. See 40 CFR part 50 App endix P . Where several39 monitors are located in a county (or a designated nonattainment area or maintenance area ), the
DV for the county or area is determined by the mo nitor with the highest DV

.

Note: Eligible monitors for providing design value data generally include State and Local Air Monitoring Stations (SLAMS) at population

- oriented locations with an FRM or FEM monitor. All data from Special Purpose Monitors (SPM) using an FRM or FEM are 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 2008 ozone NAAQS for designation purposes.

The 2010 DVs for the o zone NAAQS for counties in the Seaford Area (Sussex County, Delaware) and nearby surrou nding area are shown in Table 2

.

Table 2 . Air Quality Data

.

County State Recommended
Nonattainment? 2010 8

- hour Ozone DV (ppb)
Caroline, MD No

-- Dorchester, MD No

-- Kent, DE No 74
Sussex, DE Yes, other area 77
Talbot, MD No

-- Wicomico, MD No

-- Worcester, MD No

-- Note: Counties with no ozone monitor are indicated with “

-- “ in the 2010 8

- hour Ozone DV
column.

In accordance with section 107(d) of the Clean Air Act, EPA must designate an area nonattainment if it is violating the 2008 ozone NAAQS. Sussex County, Delaware show s a violation of the 2008 ozone NAAQS . Therefore , th is c ounty must be included in a
nonattainment area.

Note that the absence of a violating monitor is not a sufficient reason to eliminate counties a s candidates for nonattainment status based upon contribution to violations in other nearby areas

. Each county is evaluate d based on the weight o f evidence of the five factors.



### Factor 2: Emissions and Emissions

- Related Data

EPA evaluated emissions of ozone precursors ( NO
x and VOC ) and other emissions

- related data that provide information on areas contributing to violating monitors.

Emissions Data

EPA evaluated county

- level emission data for NO
x and VOC derived from the 200 8 National
Emissions Inve ntory (NEI), version 1.5

. This is the most recently available NEI. (See40 http://www.epa.gov/ttn/chief/net/2008inventory.html ) Significant emissions levels in a nearby area indicate the pote ntial for the area to contribute to observed violations. For this factor, we
also consider ed any additional information we receive on changes to emissions levels that are not reflected in recent inventories. These changes include emissions reductions due to permanent
and enforceable emissions controls that are in place before final designations are issued and
emissions increases due to new sources. EPA received no such additional emissions data for the
Seaford Area.

Table 3 shows emissions of NO
x and VOC ( in tons per year (tpy) ) for violating and potentially contributing counties in the Seaford Area

.

Table 3. Total 2008 NO
x and VOC Emissions.

County State Recommended
Nonattainment? NO

x (tpy) VOC (tpy) Caroline, MD No 983 1,324
Dorchester, MD No 1,666 3,516
Kent, DE No 7,667 5,381
Sussex, DE Yes, other area 14,870 9,972
Talbot, MD No 1,822 2,869
Wicomico, MD No 2,391 3,669
Worcester, MD No 2,154 4,860

Sussex County, Delaware has the highest NOx and VOC emissions in the area of analysis. Kent County, Delaware has the next highest emissions, but those emissions are about half that of Sussex County’s. Caroline and Talbot Counties, Maryland, have the lowest emissions. Thus, the most likely source of ozone precursors for the Seaford Area is Sussex County, Delawa re

.

P opulation density and degree of urbanization

EPA evaluated the population and vehicle use characteristics and trends in the Seaford Area and the nearby surrounding area as indicators of the probable location and magnitude of non

- point

source emissi ons . These include ozone

- creating emissions from sources such as on

- road and off

road vehicles and engines, consumer products, residential fuel combustion, and consumer
services. Areas of dense population or commercial development are an indicator of are a source and mobile source NO
x and VOC emissions that may contribute to ozone formation. Table 4
shows the population, population density, and population growth information for each county in
the area.41 Table 4 . Population and Growth.

County State
Recommended
Nonattainment? 2010 Population 2010 Population Density (1000

pop/sq mi) Absolute change in population (2000

- 2010) Population % change (2000

- 2010)
Caroline, MD No 33,066 0.10 3,241 +11%

Dorchester, MD No 32,618 0.05 35,200 +28

Kent, DE No 162,310 0.27 35,200 +28%
Sussex, DE Yes, other area 197,145 0.20 39,710 +25%

Talbot, MD No 37,782 0.12 3,890 +11%

Wicomico, MD No 98,733 0.25 13,872 +16%

Worcester, MD No 51,454 0.09 4,678 +10%
Sources: U.S. Census Bureau population estimates for 2010 as of August 4, 2011. ( http://factfinder2.census.gov/faces/tableservices/jsf/pages/productview.xhtml?pid=DEC_10_PL_GCTPL2. STO5&p rodType=table )

Sussex and Kent Count ies

, Delaware have the largest population s. Caroline, Dorchester, Talbot, and Worcester Counties in Maryland have the smallest population and are the least densely populat ed in the area of analysis. All counties in the area of analysis have experienced population growth from 2000 to 2010. Note that the eastern coast of Sussex County, Delaware has several popular beaches, including Lewes and Rehoboth. The population of these beach areas increases substantially i n the summertime (i.e., in the ozone season). Thus, non

- point

source emissions in Sussex County are higher in the ozone season than the rest of the year.

Traffic and commuting patterns

EPA evaluated the total Vehicle Miles Traveled (VMT) for each county in the Seaford Area and nearby surrounding area . In combination with the population/population density data and the location of main transportation arteries (see Figure 1, above), this information helps identify the probable location of non

- point source emissions. A county with high VMT is generally an integral part of an urban area and indicates the presence of motor vehicle emissions that may
contribute to ozone formation. Rapid population or VMT growth in a county on the urban perimeter signifies incr easing integration with the core urban area, and indicates that the
associated area source and mobile source emissions may be appropriate to include in the
nonattainment area. Table 5 shows the total VMT for each county in 2008

.

Table 5 . Traffic (VMT) D ata

. County State Recommended
Nonattainment? 2008 VMT* (million miles)
Caroline, MD No 371

Dorchester, MD No 395

Kent, DE No 1,565
Sussex, DE Yes, other area 2,122
Talbot, MD No 614

Wicomico, MD No 1,008
Worcester, MD No 645

* MOBILE model VMT are those inputs into the NEI version 1.5.42 Sussex County, Delaware has the highest VMT in the area of analysis. Furthermore, a s stated
above , the eastern coast of Sussex County, Delaware has several popular beaches, including Lewes and Rehoboth. The traffic through Sussex County to the beach areas increases substantially in the summertime (i.e., in the ozone season). Thus, VMT and mobile sourc e emissions in Sussex County are higher in the ozone season than the rest of the year. Caroline and Dorchester Counties, Maryland have the lowest VMT.

Table 6. County to County Worker Flow.

Residence County Kent,
DE Sussex,
DE Caroline,
MD Dorchester,
MD Talbot,
MD Wicomico,
MD Worcester,
MD Workplace County
Kent, DE 47,455 5,704 731 55 51 109 28 Sussex, DE 3,779 52,073 504 416 43 2,422 1,112 Caroline, MD 297 607 6,219 734 598 104 13 Dorchester, MD 68 373 566 9,391 774 844 20 Talbot, MD 121 371 3,221 1,955 12,194 274 21 Wicomico, MD 112 3,518 120 646 74 32,576 2,896 Worcester, MD 29 1,869 8 43 2 2,954 15,463 Source: US Census Bureau County

- To

- County Worker Flow Files http://www.census.gov/population/www/cen2000/commuting/index.html

As shown in Table 6, above, Kent County, Delaware; and Wicomico and Worcester Counties, Maryland have the most commuting to and from Sussex County, Delaware. Caroline, Dorchester, and Talbot Counties, Maryland have comparatively little commuting to and from Sussex County, Delaware. The counties in New Jersey have no commuters to and from Sussex
Cou nty, Delaware.



### Factor 3: Meteorology (weather/transport patterns)

EPA evaluate d available meteorological data , consisting of 30

- year average s ummertime w ind
d irections from the National Weather Service

, to help determine how weather, transport pattern s and stagnation conditions, would affect the fate and transport of precursor emissions contributing
to ozone formation in the Seaford Area

.

As shown in Figure 2 below, in Sussex County, Delaware, t he prevailing winds during the ozone

season come predomi nantly from the south

- south west

. This indicates that emissions from Kent County, Delaware and the counties in New Jersey are not expected to contribute to violations at the Sussex County, Delaware monitors. Dorchester, Wicomico, and Worcester Counties in Maryland are upwind of the violating monitors. Although emissions from those counties might contribute to violations in downwind Sussex County, Delaware, the emissions levels from those counties are so low that little actual contribution is expected.43 Figure 2. 30

- Year Average Summertime Wind Directions in Sussex County, Delaware

.

To further understand the meteorological transport conditions within the area around Seaford , we also evaluated 24

- hour back trajectories for the 2006

- 2010 time period, using the National Oceanic and Atmospheric Administration (NOAA) Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. The model uses the monitoring location as a starting point, and goes back in time using meteorological data to deter mine how a parcel of air would have traveled on a given day. EPA evaluated three separate elevations for each exceedance day to better characterize the wind pattern and pollution transport to the monitor.

For this analysis, EPA used monitor 10

- 005

- 1002 a s the starting point for the HYSPLIT back trajectories. EPA selected monitor 10

- 005

- 1002 because, of the two violating monitors in the Seaford Area, this monitor has the highest 2010 DV , 77 .3 ppb versus 77.0 ppb at monitor 10

- 005

- 100 3. EPA used HYSPILT t o evaluated wind patterns at the violating monitor for all days
where the 8

- hour average was above the 0.075 ppm standard (exceedance days) at monitor 10

- 005

- 1002

. The air quality monitoring data and HYSPLIT results for those exceedance days are
availabl e in the docket for this action. Table 7 lists the exceedance days and corresponding 8

- hour average ozone values for each exceedance day. Please note that there were no exceedance days in the Seaford Area in 2009.

Table 7. 2006 to 2010 Exceedance

- Day 8

- Hour Ozon e Values at Monitor 10

- 005

- 1002
Exceedance Day 8

- hour average (ppm ozone) Exceedance Day 8

- hour average (ppm ozone )

5/30/2006 0.083 6/12/2008 0.081

6/20/2006 0.081 6/26/2008 0.078

6/21/2006 0.079 7/12/2008 0.077

7/18/2006 0.076 7/16/2008 0.081

8/2/2006 0.082 7/17/2008 0.091

8/3/2006 0.089 7/18/2008 0.08544 Exceedance Day 8

- hour average (ppm ozone) Exceedance Day 8

- hour average (ppm ozone )

8/23/2006 0.083 8/1/2008 0.079

8/25/2006 0.078 5/6/2010 0.079

5/26/2007 0.084 6/23/2010 0.084

6/18/2007 0.081 7/5/2010 0.087

6/21/2007 0.076 7/6/2010 0.078

7/7/2007 0.078 7/7/2010 0.091

8/4/2007 0.081 8/10/2010 0.08

8/8/2007 0.084 8/11/2010 0.086

8/30/2007 0.077 8/30/2010 0.078

8/31/2007 0.078 9/24/2010 0.077

4/18/2008 0.079

Figure 3 overlays HYSPLIT 24

- hour back trajectories for all the 2006

- 2010 ozone exceedances

at monitor 10

- 005

- 1002 on a Google Earth map of the northeastern United States. It gives an overview of long

- range transport to the Seaford Area

. As seen in Figure 3, the 24

- hour back trajectories indicate regional transport f rom many directions and over several states.

Figure 3. NOAA HYSPLIT 24

- Hour Back Trajectories for 2006

- 2010 Exceedances Days

- Overview

In Figure 4, below, these EPA has zoomed in on these same 24

- hour HYSPLIT back trajectories, showing more of the ne arby transport on high ozone days. This zoomed in perspective shows45 that on exceedance days , there is no one dominant wind direction. However, on exceedance days, winds from the north, northwest, west, and southwest are more likely than winds from the east, southeast, and south.

Figure 4. NOAA HYSPLIT 24

- Hour Back Trajectories for 2006

- 2010 Exceedances Days

- Zoom View

To further illu strate the local transport situation in the Seaford Area , EPA has selected specific trajectories for two “ozone epis ode s, ” periods when the ozone levels are high for several consecutive days. As shown in Table 7 , the 8

- hour average ozone value at monitor 10

- 005

- 1002
was above the standard for three days in a row in 2008 ( July 16

- 18) and 2010 ( July 5

- 7). As
shown in Fi gures 5 through 7 , during the ozone episode in 2008, winds passed through almost all of the counties surrounding Sussex County . In Figure 5, the back trajectories pass through Kent County, Delaware , and Cape May and Cumberland Counties in New Jersey . In Figure 6, back trajectories pass through Caroline and Talbot Counties in Maryland , and Kent County, Delaware

. In Figure 7, back trajectories pass through Dorchester, Wicomico, and Worcester Counties in Maryland, and Cape May County, New Jersey

. Alt hough emissions from those counties might contribute to violations in downwind Sussex County, Delaware, the emissions levels from those counties are relatively low, and relatively little actual contribution is expected, compared to the
contribution of ozon e precursors from Sussex County.46 Figures 5, 6 & 7, NOAA HYSPLIT 24

- Hour Back Trajectories July 16

- 1 8 , 200 847 Figures 8, 9 & 10

, NOAA HYSPLIT 24

- Hour Back Trajectories July 5

- 7, 20 1048 The ozone episode in 2010 shows winds coming to Sussex County from the north, the west via Baltimore and Washington, DC, and the east via the Atlantic Ocean and New York City. This episode illustrates the regional nature of ozone. While this goes beyond the scope of the designation process, which focuses on nearby contribution to attainment, this highlights the need for rules to address transport ozone precursors, such as the Cross State Air Pollution Rule ( currently stayed by the court).



### Factor 4: Geography/topography (mountain ranges or other air basin
b oundaries)

The geography/topography analysis evaluates the physical features of the land that might affect the airshed and, therefore, the distribution of ozone over the area

.

The Seaford Area does not have any geographical or topographical barriers sign ificantly limiting
air pollution transport within its air shed. Therefore, there are no barriers to contribution from upwind areas.



### Factor 5: Jurisdictional boundaries

EPA consider s existing jurisdictional boundaries for the purposes of providing a clearly defined legal boundary and so that areas designated nonattainment have the legal authority and cooperative planning necessary to carrying out the air quality planning and enforceme nt functions for nonattainment areas. Examples of jurisdictional boundaries include existing/prior
nonattainment areas for ozone or other urban

- scale pollutants, counties, air districts, townships, metropolitan planning organizations, state lines, Reserva tions, urban growth boundary, etc. Where existing jurisdictional boundaries are not adequate to describe the nonattainment area, other clearly defined and permanent landmarks or geographic c oordinates are used.

Kent and Sussex Counties, Delaware were inc luded in the Philadelphia

- Wilmington

- Atlantic City nonattainment area for the 1997 ozone N AAQS. However, EPA is not including them in that area for the 2008 ozone NAAQS, as supported by EPA’s five

- factor analysis for the Philadelphia

- Wilmington

- Atlantic C ity area 9

.

Sussex and Kent Counties in Delaware are in separate statistical areas. Being part of a statistical

area indicates that counties are linked through employment and commuting. According to the Office of Management and Budget’s “ Standards for Defining Metropolitan and Micropolitan Statistical Areas,” published in the Federal Register on December 27, 2000 (65 FR 82228)

, the

“ general concept of a Metropolitan Statistical Area or a Micropolitan Statistical Area is that of an

area con taining a recognized population nucleus and adjacent communities that have a high degree of integration with that nucleus. ” Sussex County makes up the Seaford M icropolitan
Statistical Area

, while Kent County, Delaware makes up the Dover MSA

. The Dover/Ke nt County MPO is the planning organization for Kent County . This MPO covers 20 municipalities

9 See EPA’s Technical Analysis for the Philadelphia

- Wilmington

- Atlantic City nonattainment area.49 including all of Smyrna, which is also in New Castle County

, and all of Milford, which is also in Sussex County. While Kent County was part of the Philadelphia

- Wilmington

- Trenton
nonattainment area for the 1

- hour ozone NAAQS, Sussex County was a separate nonattainment

area.

The main jurisdiction boundaries that separate Caroline, Dorchester, Talbot, Wicomico, and
Worcester Counties

, Maryland; and Cape May and Cumberland Counties , N ew Jersey from the Seaford Area are state boundaries. Furthermore, these counties are not part of the Seaford
M icropolitan Statistical Area

. Cape May County , N ew J ersey is in the Ocean City, NJ MSA. Cumberland County, New Jersey is in the Vineland

- Millville

- Bridgeton , NJ MSA, which is part
of the Philadelphia

- Camden

- Vineland , DE

- MD

- NJ

- PA CSA. Dorchester County

, Maryland is in
the Cambridge , MD Micropolitan Statis tical Area. Talbot County, Maryland makes up the Easton, MD M icropolitan Statistical Area. Worcester County, Maryland makes up the Ocean
Pines , MD micropolitan statistical area and Wicomico County, Maryland is in the Salisbury , MD MSA, which are both par t of the Salisbury

- Ocean Pines , MD CSA. Therefore, the Seaford Area is generally unconn ected with these other counties.



### Conclusion

Based on the assessment of factors described above, EPA has concluded that Sussex County,
Delaware meets the Clean Air Ac t criteria for inclusion in its own nonattainment area, the
Seaford nonattainment area

.

Sussex County, Delaware has violating monitors and the highest emissions, population, and VMT in the area of analysis. EPA has concluded that inclusion of the other counties in this analysis in the Seaford Area is not warranted. These counties have comparatively low emissions, populations, and VMT

. Kent County, Delaware; and Cape May County, New Jersey have the next highest emissions, but those counties emissions ar e about half that of Sussex County’s. Furthermore, Cape May County is being designated in the Philadelphia

- Wilmington

- Atlantic City nonattainment area. To the exte nt that emissions from the Cape May County may contribute ozone concentrations in the Seaf ord nonattainment area, that contribution will be lessened by emission controls put in place in th at separate nonattainment area. Wind directions on ozone exceedance days show potential impacts from all counties in the area of analysis. Although emission s from those counties might contribute to violations in downwind Sussex County, Delaware, the emissions levels from those counties are relatively low, and relatively little actual contribution is expected, compared to the contribution of ozone precursors f rom Sussex County. Furthermore, the other counties in the area of analysis are not linked jurisdictionally to Sussex County and are not part of the Seaford Microplitan Statistical Area.