jACK A. MARKELL 

GovERNOR 

Mr. Shawn Garvin (3RAOO), 

STATE OF DELAWARE 

OFFICE OF THE GOVERNOR 

TATNALL BUILDING, SECOND FLOOR 

WILLIAM PENN STREET, DOVER, DE 19901 

November 21,2013 

Regional Administrator, Region III 

U.S. Environmental Protection Agency 

1650 Arch Street 

Philadelphia, PA, 19103-2029 

Dear Mr. Garvin: 

RECEIVED 

r. r:c 

,,J~ 1 ~(. 7013 

EPA, RCG;\}N 10 

01T!C6 OF REGIONAL ADMINISTR/·,TOR 

3 

PI-lONE: 302-744-4101 

E\X: 302-739-2775 

On December 14, 2012 the U.S. Environmental Protection Agency (EPA) strengthened the 

National Ambient Air Quality Standards (NAAQS) for fine particulate matter (PM2.

5) by lowering 

the annual primary standard from 15 micrograms per cubic meter (1-!g/m3

) to12 11-g/m3. Section 

107 (d) of the Clean Air Act (CAA) requires the Governor of each State to submit to the EPA a list 

of all areas (or portions thereof) in the State, designating each as nonattainment, attainment, or 

unclassifiable. This letter fulfills Delaware's obligations under Section 107 (d) of the CAA. 

Area Description and Monitoring Data 

Delaware is composed of three counties, namely New Casde, Kent and Sussex, laying from 

north to south. The northern portion of New Casde County lies above the Chesapeake and 

Delaware Canal, a waterway that connects the Chesapeake Bay with the Delaware Bay. This part of 

New Cas de County is more metropolitan and industrialized than the remainder of Delaware. The 

remainder of Delaware lies south of the Chesapeake and Delaware Canal, and comprises the 

soud1ern portion of New Casde County, and all of Kent and Sussex Counties. 

Delaware currendy monitors PM2.

5 at seven locations throughout the State. The design 

values based upon 2010 through 2012 complete and certified monitoring data are 10.4 11-g/m3

, 

9.0f-lg/m3 and 8.9 11-g/m3 for New Casde, Kent and Sussex County, respectively. This monitoring 

data indicates that PM2.

5 concentrations in Delaware's air are well below the 12 11-g/m3 NAAQS 

throughout the State. 

Attainment/N onattainment Recommendation 

Section 107 (d) of the CAA requires the EPA to designate an area "nonattainment" if it is 

violating the NAAQS, or if it is contributing to a nearby area where a violation of the NAAQS 

occurs. RECEIVED 

DEC 1 7 2013 

3AP30 
Mr. Shawn Garvin 

November 21,2013 

Page2 

RECEIVED 

D~C 11 2013 

EPA, f;.EG!G!~ !E 

1 • • 1::01- !t!~Giull! .. L AD,vlfNISTR. cl I'C 

Delaware has controlled every non-trivial source of PM2_

5 and its precur or , and all - --- · 

Delaware emission sources are now well controlled. This is demonstrated by our emissions 

inventory- between 2002 and 2012 Delaware implemented control strategies that reduced its overall 

emissions of direct PM2_

5 by 46%, and precursor's sulfur dioxide by 95%, nitrogen oxides by 47%, 

volatile organic compounds by 42% and ammonia by 52%. Monitoring data conftrms the 

effectiveness of these control strategies- in 2002 the PM2.

5 design value in New Casde County was 

16.2 f.-lg/m3

, and the emission reductions between 2002 and 2012 have reduced the design value to 

10.4 f.-lg/m3

. 

Because PM2_

5 concentrations throughout Delaware are well below the 2012 PM2_5 NAAQS, 

and because every non-trivial source of PMz.5 and its precursors are well controlled, emissions from 

Delaware do not contribute to the nonattainment of the PM2_

5 NAAQS in any area. Given this, 

each of Delaware's three counties should be designated as attainment for the annual PM2_

5 NAAQS. 

Additional documentation and analysis to support a designation of attainment is provided in the 

enclosed technical support document which address each of the ftve factors that the EPA has 

suggested in guidance (i.e., air quality data, emissions and emissions-related data, meteorology, 

geography/topography, and jurisdictional boundaries). 

Thank you for your consideration of these recommendations. If you have any questions 

concerning this submittal or would like to discuss it further, please contact Mr. Ali Mirzakhalili, 

Director of the Division of Air Quality at (302) 739-9402. 

Enclosure 

cc: Collin P. O'Mara, DNREC 

Dave Small, DNREC 

Ali Mirzakhalili, DNREC 

Diana Esher, EPA, Region III 

Sincerely, 

5~ f()~ Jack A. Markell 

Governor 
State of Delaware

Department of Natural Resources and 

Environmental Control

Division of Air Quality

Technical Support Document to Support a 

Designation of Attainment of the 2012

Fine Particle (PM2.5) NAAQS

November 21, 2013
2

Table of Contents

1 INTRODUCTION .................................................................................................................................5

2 AIR QUALITY DATA IN THE REGION............................................................................................6

2.1 Delaware PM2.5 Monitoring Network and Data ..............................................................................6

2.2 Delaware, Maryland, New Jersey and Pennsylvania Annual PM2.5 Design Values.......................8

2.3 Philadelphia County Monitoring Data for the “LAB” (ID 421010004)........................................10

2.4 Air Quality Rankings in the Philadelphia CBSA and Surrounding Counties (CBSA+)...............11

2.5 Philadelphia CBSA Trends, Seasonal and Wind Patterns.............................................................14

2.6 Speciation and “SANDWICH” Analysis ......................................................................................20

2.7 Chester Monitor (Delaware County, PA)......................................................................................24

2.8 Summary of Air Quality Analysis.................................................................................................25

3 METEOROLOGY (WEATHER/TRANSPORT PATTERNS) ..........................................................27

3.1 General Comments........................................................................................................................27

3.2 Trajectory Cluster Analysis...........................................................................................................27

3.3 Summary of Trajectory Cluster Analysis......................................................................................33

4 EMISSIONS AND EMISSIONS-RELATED DATA .........................................................................34

4.1 2011 EPA National Emissions Inventory......................................................................................34

4.2 Emissions Related Data.................................................................................................................35

4.2.1 Population ..............................................................................................................................35

4.2.2 Expected growth.....................................................................................................................39

4.2.3 Traffic and commuting patterns.............................................................................................40

4.2.4 Vehicle Miles Traveled..........................................................................................................41

4.3 Emission Reductions.....................................................................................................................42

4.3.1 General Discussion.................................................................................................................42

4.3.2 Delaware’s 2012 Point Source Reductions Since 2002 .........................................................43

4.3.3 CBSA Emission Reductions between 2002 and 2011 ...........................................................43

4.3.4 Philadelphia CBSA and CBSA+ 2002 and 2011 Emissions and Reductions........................47

4.4 Control Measure Analysis for PM2.5-Related Pollutants...............................................................50

4.4.1 Sulfur Dioxide (SO2)..............................................................................................................50

4.4.2 Oxides of Nitrogen (NOx) .....................................................................................................51

4.4.3 Direct PM2.5............................................................................................................................52

4.4.4 Volatile Organic Compounds (VOC) ....................................................................................52

4.4.5 Ammonia (NH3).....................................................................................................................52

4.5 Summary of Emissions and Control Measure Analysis................................................................53

5 GEOGRAPHY/TOPOGRAPHY.........................................................................................................53

6 JURISDICTIONAL BOUNDARIES ..................................................................................................53

7 CONCLUSIONS..................................................................................................................................54
3

List of Figures

Figure 2.1: Delaware PM2.5 Air Monitoring Locations ................................................................................7

Figure 2.2: CBSA+ Violating Counties and Color-Coded Design Values per County ...............................10

Figure 2.3: Philadelphia County 2010-2012 PM2.5 annual averages ..........................................................11

Figure 2.4: Trends in annual average design values...................................................................................14

Figure 2.5: Average DV Trends for New Castle, Chester and Delaware Counties....................................15

Figure 2.6: MLK, Chester and New Garden Cool vs. Warm Season .........................................................16

Figure 2.7: MLK, Chester and New Garden No. of High Days..................................................................16

Figure 2.8: MLK/Chester High Concentration Days..................................................................................17

Figure 2.9: MLK/Chester High Day Difference .........................................................................................18

Figure 2.10: Chester PM2.5 Concentrations by Wind Direction (WD) Radar Plot .....................................19

Figure 2.11: Chester PM2.5 Concentrations by Wind Direction Bar Chart.................................................19

Figure 2.12: MLK PM2.5 Concentrations by Wind Direction (WD) Radar Plot.........................................19

Figure 2.13: MLK PM2.5 Concentrations by Wind Direction (WD) Bar Chart..........................................20

Figure 2.14: Brigantine Speciated SANDWICH ........................................................................................21

Figure 2.15: MLK Speciated SANDWICH ................................................................................................21

Figure 2.16: Chester Speciated SANDWICH.............................................................................................22

Figure 2.17: MLK and Chester vs. Brigantine Urban Excess.....................................................................23

Figure 2.18: MLK non-SANDWICH data..................................................................................................23

Figure 2.19: 2011 Points Source Emissions vs. Distance from Chester Monitor.......................................24

Figure 3.1: 24-hour HYSPLIT back trajectories originated at 2:00 pm from MLK DE (top) and Chester 

PA (bottom) monitors for 2010-2012 colored by PM2.5 concentration (μg/m3

)..........................................28

Figure 3.2: Six clusters to back trajectories at MLK DE (top) and Chester PA (bottom) monitors for 

2010-2012 showing the mean trajectory for each cluster ............................................................................29

Figure 3.3: Variation of PM2.5 by month and hour of the day by wind direction cluster at MLK DE (top) 

and Chester PA (bottom) monitors for 2010................................................................................................31

Figure 3.4: Variation of PM2.5 by month and hour of the day by wind direction cluster at MLK DE (top) 

and Chester PA (bottom) monitors for 2011................................................................................................32

Figure 3.5: Variation of PM2.5 by month and hour of the day by wind direction cluster at MLK DE (top) 

and Chester PA (bottom) monitors for 2012................................................................................................33

Figure 4.1: NCC 3-year Rolling DVs vs. NCC Population (over 10 years)...............................................38

Figure 4.2: Philadelphia CBSA 2002-2011 Reductions and Rankings ......................................................45

Figure 4.3: Philadelphia CBSA 2002-2011 Percent Reductions ................................................................46
4

List of Tables

Table 2.1: Delaware PM2.5 Annual Mean Concentrations; NAAQS = 12 μg/m3

, 3- year average ..............8

Table 2.2: 2010-2012 DV for the Philadelphia CBSA+ ...............................................................................8

Table 2.3: Philadelphia CBSA Monitors: annual PM2.5 mean and 2010-2012 DVs ..................................12

Table 2.4: Philadelphia 2010-2012 DVs (Spatial Averaging) ....................................................................12

Table 2.5: New Castle and Adjacent Counties’ 2010-2012 Design Values (ranked low-to-high).............13

Table 2.6: 2009 Speciated SANDWICH Data............................................................................................20

Table 2.7: MLK and Chester vs. Brigantine Urban Excess........................................................................22

Table 3.1: Numbers of Each Cluster by Monitor........................................................................................30

Table 4.1: 2011 NEI Philadelphia CBSA+ .................................................................................................34

Table 4.2: 2011 NEI Philadelphia CBSA ...................................................................................................35

Table 4.3: 2000-2010 Population Statistics - Philadelphia CBSA+ ...........................................................36

Table 4.4: Top 25 CBSA - Attainment Status (2009-2011 DVs) ...............................................................37

Table 4.5: 2010-2035 Population, Growth and Rankings – Philadelphia CBSA+.....................................39

Table 4.6: CBSA+ Commuting Patterns.....................................................................................................40

Table 4.7: CBSA+ 2002-2010 Vehicle Miles Traveled and Rankings.......................................................41

Table 4.8: New Castle County - Top Point Source Emitters in 2002 and 2012 .........................................43

Table 4.9: Philadelphia CBSA 2002 Emissions and Rank .........................................................................44

Table 4.10: Philadelphia CBSA 2011 Emissions and Rank .......................................................................44

Table 4.11: Philadelphia CBSA 2002-2011 Reductions and Rankings......................................................45

Table 4.12: Philadelphia CBSA 2002-2011 Percent Reductions................................................................46

Table 4.13: Philadelphia CBSA+ 2002 Emissions and Total Rank............................................................47

Table 4.14: Philadelphia CBSA+ 2011 Emissions and Rankings ..............................................................48

Table 4.15: Philadelphia CBSA+ 2002-2011 Emission Reductions and Rankings....................................49

Table 4.16: Philadelphia CBSA+ 2002-2011 Percent Reductions and Rankings.......................................49
5

1 INTRODUCTION

On December 14, 2012 the U.S. Environmental Protection Agency (EPA) strengthened the National 

Ambient Air Quality Standards (NAAQS) for fine particulate matter (PM2.5) by lowering the annual 

primary standard from 15 micrograms per cubic meter (μg/m3

) to 12 μg/m3. Section 107(d) of the Clean 

Air Act (CAA) requires “... not later than 1 year after promulgation of a new or revised national ambient 

air quality standard ... the Governor of each State shall ... submit to the Administrator a list of all areas 

(or portions thereof) in the State, designating as— (i) nonattainment, any area that does not meet (or that 

contributes to ambient air quality in a nearby area that does not meet) the national primary or secondary 

ambient air quality standard for the pollutant...”

The CAA uses the nonattainment designation to establish the area where CAA control requirements are 

applied. Both areas that do not meet a NAAQS, and areas that contribute to air quality in a nearby area 

that does not meet a NAAQS are required to apply the CAA control requirements. The CAA clearly and 

completely sets a path that leads to attainment -- requiring controls, in both the area with bad air quality 

and the nearby areas that are causing the bad air quality, will lead to clean air; while controlling only one 

area but not the other may not.

Regarding air quality in Delaware, Delaware currently monitors PM2.5 at seven locations throughout the 

State. The design values based upon 2010 through 2012 complete and certified monitoring data are 10.4 

μg/m3, 9.0 μg/m3 and 8.9 μg/m3 for New Castle, Kent and Sussex County, respectively. This monitoring 

data indicates that PM2.5 concentrations in Delaware’s air are well below the 12 μg/m3 NAAQS 

throughout the State.

Regarding Delaware’s contribution to air quality in any nearby area, the word “contributes” in context of 

CAA 107 does not necessarily mean “any contribution,” but rather a degree of contribution sufficient to 

deem an area nonattainment. Given that the purpose of a nonattainment designation is to establish the 

area where the CAA control requirements are to be applied, it is reasonable to conclude that an area 

contributes if the application of CAA control requirements in that area would result in emission 

reductions that will help the nearby area meet a NAAQS. Conversely, if the application of CAA control 

requirements will not result in emission reductions in the area, then that area does not contribute to the air 

quality and would not be designated nonattainment.

This document presents Delaware data and analysis relevant to five factors EPA outlines in their April 

2013 guidance1 which they believe are appropriate to consider when making nonattainment boundary 

recommendations (i.e., air quality data, emissions and emissions-related data, meteorology, 

geography/topography, and jurisdictional boundaries). This technical analysis focuses on the 

Philadelphia-Camden-Wilmington, PA-NJ-DE-MD Combined Statistical Area (CBSA) area and a ring of 

counties surrounding that area (hereafter referred to as the “CBSA+”). The data and analysis in this 

document indicate that Delaware does contribute a small amount to air quality in nearby areas that do not 

meet the PM2.5 NAAQS, and that 1) the air quality in those areas is impacted by a different set of sources, 

and is otherwise different than the air quality in Delaware, and 2) Delaware PM2.5 and PM2.5 precursor 

emission sources are currently well controlled, and the application of CAA control requirements in 

Delaware would result in no additional emission reductions. Delaware concludes based on this data and 

analysis that Delaware emissions do not contribute a sufficient amount to any area to deem any part of 

Delaware nonattainment for PM2.5.

 1 “Designations for the Fine Particle National Ambient Air Quality Standards,” April 2013
6

2 AIR QUALITY DATA IN THE REGION

EPA recommends that states consider the air quality in areas included versus excluded from the 

nonattainment area as one of the factors in determining appropriate nonattainment area boundaries. Given 

that monitoring data indicates all areas of Delaware are attaining the PM2.5 standard, this analysis focuses 

on how the air quality in Delaware compares to the air quality in any nearby area that the EPA may 

associate with Delaware. In this Section Delaware evaluates the air quality within the Philadelphia CBSA 

and CBSA+, and demonstrates that the New Castle County attainment area is separate and distinct from 

any nonattainment problems in the CBSA. 

2.1 Delaware PM2.5 Monitoring Network and Data

Delaware began official PM2.5 monitoring in 1999. Delaware’s PM2.5 network consists of seven (7) 

monitoring sites. There are four (4) sites in New Castle County, two (2) in Kent County and one (1) in 

Sussex County. 

The primary goal of the PM2.5 monitoring network in Delaware is to determine the status of the ambient 

air with respect to the 24-hour and annual average PM2.5 NAAQS. In accordance with federal regulations, 

state agencies must operate at least the minimum number of required PM2.5 sites listed in 40 CFR Part 58 

Appendix D Table D-5. These required monitoring stations or sites must be sited to represent 

community-wide air quality. In addition, the following specific criteria also apply:

(1) At least one monitoring station is to be sited in a population-oriented area of expected maximum 

concentration. 

(2) For areas with more than one required station, a monitoring station is to be sited in an area of poor 

air quality.

(3) Each State shall install and operate at least one PM2.5 site to monitor for regional background and 

at least one PM2.5 site to monitor regional transport. 

Figure 2.1 shows the locations of Delaware’s PM2.5 monitors. All data from these monitors are measured 

using EPA approved federal reference methods (FRM). All PM2.5 monitoring sites are located

appropriately and are eligible for comparison to the annual and daily PM2.5 NAAQS. The standard 

monitoring schedule is one in three days, with one site, Martin Luther King (MLK) in Wilmington, 

monitoring every day. MLK is also designated a collocated site, with the collocated monitor designated 

as MLK-b operating on a one in six day schedule. All data are submitted to EPA’s Air Quality System 

(AQS) in a timely manner in accordance with the schedule prescribed by EPA.

Chemical speciation is encouraged at sites where the chemically resolved data would be useful in 

developing SIPs and supporting atmospheric or health effects related studies. Chemical speciation is 

conducted at MLK in Wilmington and Dover in Kent County. The PM2.5 chemical speciation sites 

include analysis for elements, selected anions and cations, and carbon. 
7

Figure 2.1: Delaware PM2.5 Air Monitoring Locations

Delaware’s original PM2.5 monitoring network design and monitor siting were completed in accordance 

with EPA requirements and guidance as stated in 40 CFR Part 58 Appendices D and E, and the EPA 

Office of Air Quality Planning & Standards (OAQPS) document “Guidance for Network Design and 

Optimum Site Exposure for PM2.5 and PM10” (EPA 1997a). Final network documents were submitted to 

EPA Region 3 in June 1998, and EPA approved Delaware’s PM2.5 monitoring network. 

Delaware Annual Ambient Air Monitoring Network Reviews, including PM2.5, have been completed each 

year in accordance with 40 CFR Part 58 Appendix D and subsequently submitted to EPA Region 3 for 

approval.

In fulfillment of the federal CAA 103 grant requirements, Delaware submits annual Delaware Data 

Quality Assessments for PM2.5 speciation data and PM2.5 FRM data to EPA Region 3. All data complies

with appropriate federal and state requirements, including 40 CFR Part 50 Appendices L and N, and 40 

CFR Part 58 Appendix A.

In fulfillment of the federal CAA 103 grant requirements, Delaware also submits annual PM2.5 Speciation 

Monitoring Network Review and Monitoring Strategy reports to EPA Region 3. The PM2.5 speciation 

network design and monitor siting follows EPA requirements and guidance as stated in 40 CFR Part 58 

Appendices D and E, and the documents “Guidance for Network Design and Optimum Site Exposure for 

PM2.5 and PM10" (EPA 1997a), “Particulate Matter (PM2.5) Speciation Guidance” (EPA 1999), and 

“Guideline on Speciated Particulate Monitoring” (EPA 1999a).

Delaware has quality assured all data in accordance with 40 CFR 58.10 and all other federal requirements. 

Delaware has recorded the data in the AQS database and, therefore, the data are available to the public. 
8

The Delaware-monitored annual mean PM2.5 concentrations and site information for 2010-2012 are 

provided in Table 2.1, and show that all sites are monitoring PM2.5 concentrations that are well below the 

2012 PM2.5 NAAQS. 

Table 2.1: Delaware PM2.5 Annual Mean Concentrations; NAAQS = 12 μg/m3

, 3-

year average

County Site Name and ID Number 2010 2011 2012 3-year Average

New Castle

Bellefonte 10-003-1003 10.2 9.4 9.3 9.6

MLK 10-003-2004 10.6 10.3 10.3 10.4

Newark 10-003-1012 10.4 10.4 9.4 10.1

Lums Pond 10-003-1007 10.0 8.8 8.5 9.1

Kent Dover 10-001-0003 9.7 9.1 8.1 9.0

Killens Pond 10-001-0002 9.3 8.6 8.1 8.7

Sussex Seaford 10-005-1002 9.9 8.7 8.2 8.9

2.2 Delaware, Maryland, New Jersey and Pennsylvania Annual PM2.5 Design Values

Table 2.2 shows the 2010-2012 annual PM2.5 design values (DV) and rankings for counties within the 

CBSA+. 

Table 2.2: 2010-2012 DV for the Philadelphia CBSA+

State County** CBSA Site

2010-2012 

Annual 

DV 

(μg/m3) Rank

PA Philadelphia

Philadelphia-CamdenWilmington, PA-NJ-DE-MD 421010004 13.5 NA 1.

PA Northampton

Allentown-Bethlehem-Easton, 

PA-NJ 420950025 13.2 1

PA Delaware

Philadelphia-CamdenWilmington, PA-NJ-DE-MD 420450002 13.1 2

PA Chester

Philadelphia-CamdenWilmington, PA-NJ-DE-MD 420290100 12.3 3

PA Lancaster Lancaster, PA 420710007 12.1 4

PA York York-Hanover, PA 421330008 11.7 5

PA Philadelphia

Philadelphia-CamdenWilmington, PA-NJ-DE-MD 421010055 11.0 6

PA Berks Reading, PA 420110011 10.9 7

PA Bucks

Philadelphia-CamdenWilmington, PA-NJ-DE-MD 420170012 10.9 8

PA Philadelphia

Philadelphia-CamdenWilmington, PA-NJ-DE-MD 421010047 10.9 8

PA Philadelphia

Philadelphia-CamdenWilmington, PA-NJ-DE-MD 421010057 10.8 9
9

State County** CBSA Site

2010-2012 

Annual 

DV 

(μg/m3) Rank

MD Cecil

Philadelphia-CamdenWilmington, PA-NJ-DE-MD 240150003 10.4 10

DE New Castle

Philadelphia-CamdenWilmington, PA-NJ-DE-MD 100032004 10.4 10

MD Kent Not Applicable 240290002 10.3 11

DE New Castle

Philadelphia-CamdenWilmington, PA-NJ-DE-MD 100031012 10.1 12

PA Montgomery

Philadelphia-CamdenWilmington, PA-NJ-DE-MD 420910013 9.8 13

NJ Camden

Philadelphia-CamdenWilmington, PA-NJ-DE-MD 340070002 9.7 14

DE New Castle

Philadelphia-CamdenWilmington, PA-NJ-DE-MD 100031003 9.6 15

PA Philadelphia

Philadelphia-CamdenWilmington, PA-NJ-DE-MD 421010024 9.6 15

PA Philadelphia

Philadelphia-CamdenWilmington, PA-NJ-DE-MD 421011002 9.6 15

NJ Camden

Philadelphia-CamdenWilmington, PA-NJ-DE-MD 340071007 9.5 16

NJ Mercer Trenton, NJ 340210008 9.5 17

NJ Warren

Allentown-Bethlehem-Easton, 

PA-NJ 340410006 9.4 18

NJ Gloucester

Philadelphia-CamdenWilmington, PA-NJ-DE-MD 340150004 9.3 19

DE New Castle

Philadelphia-CamdenWilmington, PA-NJ-DE-MD 100031007 9.1 20

DE Kent Dover, DE 100010003 9.0 21

NJ Atlantic Atlantic City-Hammonton, NJ 340011006 8.9 22

DE Kent Felton, DE 100010002 8.7 23

NJ Warren

Allentown-Bethlehem-Easton, 

PA-NJ 340410007 8.6 24

NJ Ocean

New York-Newark-Jersey City, 

NY-NJ-PA 340292002 8.5 25

NJ Atlantic Atlantic City-Hammonton, NJ 340010006 8.2 26

NJ Mercer Trenton, NJ 340218001 8.2 26

NJ Middlesex

New York-Newark-Jersey City, 

NY-NJ-PA 340230006 8.0 27

** Counties within the Philadelphia CBSA are in bold font

NA = Not applicable

1. Philadelphia monitor ID 421010024 (LAB) is only included in this table for completeness (i.e., to show all monitors in the 

CBSA+). Delaware agrees with the City of Philadelphia that this monitor is not appropriate for comparison to the 2012 PM2.5

NAAQS designations, for reasons discussed in Section 2.3. 

As can be seen in Table 2.2, four counties in the CBSA+, all in Pennsylvania, have 2010-2012 DV’s that 

exceed the NAAQS, and design values outside of these four counties are well in compliance with the 

NAAQS. The highest monitor in Delaware’s New Castle County (i.e., the MLK monitor in downtown 

Wilmington) ranks 10th out of the 33 monitors in the CBSA+ (tied with the rural Cecil County, MD
10

monitor), and the lowest monitor in New Castle County ranks 20th. These data indicate that the air quality 

in the CBSA+ is well below the NAAQS except for the four, non-contiguous Pennsylvania counties. 

Figure 2.2 illustrates the color-coded DVs in one μg/m3 increments using 2010-2012 PM2.5 data for each 

county in the CBSA+.

2

 The map also shows the violating monitors/DVs in southeast PA, and also 

demonstrates the relatively low DVs for those counties encircling the violating monitors. 

Figure 2.2: CBSA+ Violating Counties and Color-Coded Design Values per County

2.3 Philadelphia County Monitoring Data for the “LAB” (ID 421010004)

In accordance with the PM2.5 NAAQS rule published on January 15th, 2013 (78 FR 3086), and specific to 

the provisions detailed in §58.10 (b)(13) and §58.11(e), the City of Philadelphia Air Management 

Services (AMS) requested EPA not use the Federal Equivalent Method (FEM) data from the “LAB” (ID 

 2 See map legend for description of the incremental maximum (Max) DV.
11

421010004) for NAAQS designation purposes for the years 2011 – 2013, Quarter 1.3

 In 2011 this 

monitor was switched from Federal Reference Method (FRM) to FEM. Delaware agrees with 

Philadelphia’s rationale for this request. Figure 2.3 provides annual means for 2010, 2011 and 2012 and 

demonstrates how the other Philadelphia county monitors are trending downward, while the LAB’s PM2.5

values show an unusually sharp rise beginning in 2011 with the installation of the FEM monitor.

4

 The 

LAB FEM monitor annual mean is ≥ 60% higher than the other monitors in the same county. 

Figure 2.3: Philadelphia County 2010-2012 PM2.5 annual averages

Delaware does not consider the Philadelphia LAB station to be reflective of the PM2.5 NAAQS regional 

contributions, and does not consider it suitable for comparison to the NAAQS. Delaware will not include 

this monitor further in this document. 

2.4 Air Quality Rankings in the Philadelphia CBSA and Surrounding Counties (CBSA+)

Table 2.3 shows the 2010-2012 monitoring data for all of the monitors in the Philadelphia CBSA.

 3 40 CFR Part 58.11(e) documents the process for excluding PM2.5 FEM data from comparison to the NAAQS and/or AQI if 

the performance criteria described in Table C-4 of Subpart C are not met when assessed with a collocated FRM monitor. In 

their 2013-2014 Air Monitoring Network Plan, the City of Philadelphia AMS requested PM2.5 FEM data from 2011 through the 

first quarter of 2013 at the LAB monitoring site (AQS ID 421010004) be excluded from comparison to the NAAQS and Air 

Quality Index. The request to exclude data and the assessment generated to determine FEM incomparability to a collocated 

Federal Reference Method is located in Appendix B of their report located at: 

http://www.phila.gov/health/pdfs/2013_14AMNPFinalwAppendices__20130628.pdf 4 421010024 was shutdown in 2011 and 421011002 begin operations in 2011. 

8.0

9.0

10.0

11.0

12.0

13.0

14.0

15.0

16.0

17.0

μg/m3

Philadelphia Monitor ID

2010

2011

2012
12

Table 2.3: Philadelphia CBSA Monitors: annual PM2.5 mean and 2010-2012 DVs

State County Site ID 2010 2011 2012

2010-

2012 DV Rank

PA Delaware 420450002 13.5 12.9 12.8 13.1 1

PA Chester 420290100 13.8 13.3 9.8 12.3 2

PA Philadelphia 421010055 11.3 11.4 10.3 11.0 3

PA Bucks 420170012 10.5 11.5 10.7 10.9 4

PA Philadelphia 421010047 10.9 11.3 10.2 10.8 5

PA Philadelphia 421010057 10.9 11.4 10.1 10.8 6

MD Cecil 240150003 11 10.9 9.3 10.4 7

DE New Castle 100032004 10.6 10.3 10.3 10.4 7

DE New Castle 100031012 10.4 10.4 9.4 10.1 8

PA Montgomery 420910013 9.5 10.3 9.7 9.8 9

NJ Camden 340070002 * * 9.7 9.7 10

PA Philadelphia 421011002 * 9 10.3 9.7 10

DE New Castle 100031003 10.2 9.4 9.3 9.6 11

PA Philadelphia 421010024 9.6 * * 9.6 11

NJ Camden 340071007 9.5 10.1 9 9.5 12

NJ Gloucester 340150004 9.1 9.4 9.4 9.3 13

DE New Castle 100031007 10 8.8 8.5 9.1 14

Table 2.3 shows that the air quality in two Pennsylvania CBSA counties exceed the NAAQS, and that the 

air quality in New Castle County is significantly better. The air quality in New Castle County ranks 7th

(tied with Cecil County, MD) at its worst monitor, and has the best air quality in the entire CBSA at its 

lowest monitor.5

 

In order to better illustrate county-wide air quality Delaware incorporated spatial averaging for those 

Philadelphia CBSA counties that have more than one monitoring site. Table 2.4 presents the resultant 

DVs.

Table 2.4: Philadelphia 2010-2012 DVs (Spatial Averaging)

State County Site ID 2010-2012 AVG. Rank

PA Delaware 420450002 13.1 1

PA Chester 420290100 12.3 2

PA Bucks 420170012 10.9 3

MD Cecil 240150003 10.4 4

PA Philadelphia AVERAGE 10.4 5

PA Montgomery 420910013 9.8 6

DE New Castle AVERAGE 9.8 6

NJ Camden AVERAGE 9.6 7

NJ Gloucester 340150004 9.3 8

 5 Note that New Castle County ranked 2nd highest DV in the Philadelphia CBSA under the previous 1997 annual NAAQS, 

which shows that Delaware’s PM2.5 control strategies have been effective. This is discussed in detail in Section 4.4 of this 

document.
13

Note that only two counties in Pennsylvania exceed the NAAQS, and that the air quality in the other 

CBSA counties is significantly cleaner. Of the 8 CBSA counties New Castle County is tied at 6th place 

with Montgomery County at 9.8 μg/m3.

6

Relative to New Castle County, Delaware there are five CBSA counties in four states which encircle and 

are adjacent to New Castle County, Delaware. The 2010-2012 DVs for each of these counties, and the 

percentage the DV is above or below the NAAQS, is shown in Table 2.5. 

Table 2.5: New Castle and Adjacent Counties’ 2010-2012 Design Values (ranked low-to-high)

County/State Site Name and ID Number 2010-2012

Design Value

Percent

Below/Above NAAQS

Gloucester, NJ Gibbstown Municipal Bldg.

34-015-5001 9.7 -19% 

New Castle, DE MLK (highest of 4 monitors in New

Castle County),

10-003-2004

10.4 -13%

Cecil, MD Fair Hill

24-015-0003

10.4 -13%

Philadelphia, PA RIT (24th and Ratner)

42-101-0055 11.0 -8%

Chester, PA New Garden Airport

42-029-0100

12.3 +2%

Delaware, PA

Front St & Norris St

42-045-0002 13.1 +8%

Table 2.5 shows there are two violations of the 2012 PM2.5 NAAQS which are occurring solely in the 

Pennsylvania Counties (assuming EPA will exclude the Philadelphia “LAB” for designation purposes). 

Based on the data in Table 2.4 and Table 2.5 it is evident that; 1) Delaware county is significantly above 

the NAAQS, 2) Chester county is slightly above the NAAQS, 3) New Castle County is significantly 

below the NAAQS, and 4) New Castle County’s highest DV (of 4 monitors) is 21% lower than the 

Chester monitor DV. 

 6 Note that the average of New Castle County’s four monitors is below that of Cecil County MD, which EPA excluded from 

the Philadelphia based non-attainment boundaries under the 1997 and 2006 PM2.5 NAAQS due to low DVs, and because it was 

not as “industrialized” as the rest of the CBSA. Delaware believes this low New Castle County averaged DV is a direct result 

of Delaware’s control strategies implemented under the last two rounds of PM2.5 standards.
14

2.5 Philadelphia CBSA Trends, Seasonal and Wind Patterns 

Air quality in the Philadelphia CBSA has shown significant improvement in relation to PM2.5

concentrations. Trends in annual average design values are shown in Figure 2.4, which for clarity 

includes only those sites in the CBSA with data through 2012. The dashed line indicates the PM2.5

national ambient air quality standard for the annual average. Only two sites in New Castle County (the 

highest concentration site at MLK in downtown Wilmington and the Bellefonte site located between 

MLK and the Delaware County, PA monitoring site in Chester) are shown.

Figure 2.4: Trends in annual average design values

Figure 2.4 demonstrates the continued improvement in air quality as shown by the decreasing trends in 

annual average design values. It should be noted that in the 2007 – 2009 time frame two sites began to 

show somewhat different trends –New Garden in Chester County PA and Chester in Delaware County PA

which are the only two sites in the CBSA that are currently monitoring nonattainment for the 2012 

NAAQS. The New Garden site changed methods from FRM to FEM in 2009, which has a possible high 

bias in comparison to the FRM. According to data submitted to EPA AQS, the FRM resumed sampling at 

New Garden in 2012, and there was a corresponding drop in design value (see Table 2.3, Site ID 

420290100); which is more in line with other regional sites. It is likely that considering the past trend 

when the FRM monitor was in use at this site, in the future when additional years of data from the FRM 

monitor are incorporated we will see that PM2.5 concentrations do actually trend with the other CBSA 

sites, and that the design value at New Garden will be below the annual NAAQS.

The Chester site in Delaware County PA showed a slower rate of improvement beginning in 2007-2009, 

and slightly increased in annual average design value concentrations in the most recent three year period 

(2010-2012). As trends in other regional monitors indicate, as regional PM2.5 ambient concentrations and 

transport levels continue to improve, nearby local sources may become relatively more significant. It is 

8.0

9.0

10.0

11.0

12.0

13.0

14.0

15.0

16.0

17.0

Phila. Area Design Values Fair Hill MD

Bellefonte DE

MLK DE

New Garden PA

Chester PA

Bristol PA

Lycoming PA*

Norristown PA

S. Broad PA

Ritner PA

Sp. Grdn PA

Camden NJ

Gloucester NJ
15

likely that local sources have a significant influence on the Chester PA monitor and that local sources are 

the reason the Chester PA monitor does not follow the trend of the other CBSA monitors. The siting of 

the Chester monitor is discussed in detail in section 2.7 of this document.

Figure 2.5 shows annual average design value trends for PM2.5 sites in New Castle County DE along with 

the New Garden and Chester monitors in the adjoining PA counties (Chester and Delaware Counties, 

respectively). The same trends discussed above are more clearly seen in this chart with the PA monitors 

showing clear differences compared to the New Castle County DE monitors.

Figure 2.5: Average DV Trends for New Castle, Chester and Delaware Counties

To further examine similarities and differences in the PM2.5 concentrations and trends among the sites, the 

highest concentration monitoring site in New Castle County (MLK in Wilmington) DE was compared to 

the New Garden PA (Chester County) and Chester PA (Delaware County) monitoring sites. Following 

EPA guidance as contained in the April 13, 2013 PM2.5 Designation Guidance Memo to EPA Regional 

Administrators, high concentration days were identified and assessed for each monitoring site by 

occurrences in warm or cool season as well as by month.

For each site, the 95th percentile was calculated for the three year period of 2010-2012 as per EPA 

guidance, and high concentration days were defined as exceeding that concentration. Cool and warm 

seasons were defined as per EPA guidance as cool season equal to October through December and 

January through April, and warm season as May through September for each calendar year.

Figure 2.6 shows that both MLK in DE and Chester in PA have more high concentration days in the cool 

season while New Garden has more high concentration days in the warm season. 

8.0

9.0

10.0

11.0

12.0

13.0

14.0

15.0

16.0

17.0

ug/m3

Annual Standard Design Value Trends

New Garden. PA Chester, PA MLK, DE

Bellefonte, DE Newark, DE Lums Pond, DE
16

Figure 2.6: MLK, Chester and New Garden Cool vs. Warm Season

Further breakdown of high concentration days by month in Figure 2.7 confirms this pattern. 

Figure 2.7: MLK, Chester and New Garden No. of High Days 

0

5

10

15

20

25

30

35

Cool Warm

Number high days by cool or warm season 

2010-2012

MLK Chester New Garden

0

2

4

6

8

10

12

14

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Number high days per month 2010-2012

MLK Chester New Garden
17

In the warm season, sulfates dominate the composition of PM2.5 and are generally an indication of 

regional transport; high concentrations in the cool season are dominated by shorter range components and 

are generally more indicative of local source impacts. More information on PM2.5 composition is 

presented in section 2.6.

The seasonal breakdown and design value trends indicate that the New Garden monitor in Chester 

County, PA is not representative of PM2.5 concentrations or trends in the New Castle County, DE or 

Delaware County, PA areas. Since the ambient data from the New Garden site is only slightly above the 

annual average NAAQS and shows decreasing concentrations, and given the likely problem with the FEM 

monitor discussed above, further detailed analysis of the data from this site is not included in the 

following analyses which focus on identifying characteristics of the PM2.5 data from the highest 

Philadelphia CBSA design value site at Chester (Delaware County, PA) and the MLK site which is the 

highest concentration monitor in New Castle County, DE.

Because the Chester PA site is similar in seasonal pattern to the MLK DE site, same day high 

concentrations for both sites were compared and the difference in concentration plotted as time series 

graphs as seen in Figure 2.8 and Figure 2.9.

Figure 2.8: MLK/Chester High Concentration Days

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

1/14/2010

2/2/2010

3/11/20106/27/2010

7/6/2010

8/10/20109/24/2010

12/17/201012/19/201012/30/2010

1/1/20116/1/2011

7/20/20117/22/2011

12/13/2011

6/22/2012

11/10/201212/15/2012

ug/m3

2010-2012 High Concentration Days 

MLK and Chester

MLK-a Chester
18

Figure 2.9: MLK/Chester High Day Difference

Figure 2.9 shows an increasing difference with time between concentrations at MLK and Chester, which 

is in agreement with the decreasing trend in average concentrations at MLK and a flat or slightly 

increasing trend at Chester. All other monitoring sites in the Philadelphia CBSA also show the decreasing 

trend similar to MLK (Figure 2.5). This data supports the interpretation that as regional transport PM2.5

contributions decrease, local sources are becoming more significant at the Chester PA site. As the 

Chester site is becoming dominated by local source influences, it can therefore no longer be considered as 

representative of the wider Philadelphia CBSA

To further examine local versus regional influences on PM2.5 concentrations, analysis of wind directions 

associated with PM2.5 concentrations is useful. Both MLK and Chester have continuous PM2.5 FEM 

monitor data, which is more meaningful for comparison with wind direction data than 24-hour average 

PM2.5 data. The hourly PM2.5 FEM concentrations at MLK DE and Chester PA for 2010 through 2012 

were plotted by hourly average wind direction as shown in the following figures. Both radar plots and bar 

charts are shown as different ways to visualize the same data.

The Chester site shows higher average concentrations when winds are from the Northeast (40 to 80 

degrees) and Southwest (200 to 280 degrees) as shown in Figure 2.10 and Figure 2.11, while the MLK 

DE site shows a less pronounced broader range of high concentrations associated with winds from 

Southeast through Southwest (100 degrees to 240 degrees), as shown in Figure 2.12 and Figure 2.13.

-4.0

-2.0

0.0

2.0

4.0

6.0

8.0

10.0

12.0

1/14/2010

2/2/2010

3/11/20106/27/2010

7/6/2010

8/10/20109/24/2010

12/17/201012/19/201012/30/2010

1/1/20116/1/2011

7/20/20117/22/2011

12/13/2011

6/22/2012

11/10/201212/15/2012

ug/m3

Chester - MLK Difference 

high concentration days 2010-2012
19

Figure 2.10: Chester PM2.5 Concentrations by Wind Direction (WD) Radar Plot

Figure 2.11: Chester PM2.5 Concentrations by Wind Direction Bar Chart

Figure 2.12: MLK PM2.5 Concentrations by Wind Direction (WD) Radar Plot

0.00

5.00

10.00

15.00

20.00

0

20

40

60

80

100

120

140

160

180

200

220

240

260

280

300

320

340

Chester PM2.5 FEM by WD

PM2.5

Avg

0.00

5.00

10.00

15.00

20.00

0-20

21-4041-6061-80

81-100

101-120121-140141-160161-180181-200201-220221-240241-260261-280281-300301-320321-340341-360

Chester PM2.5 FEM by WD

PM2.5 Avg

0.00

5.00

10.00

15.00

0

20

40

60

80

100

120

140

160

180

200

220

240

260

280

300

320

340

MLK PM2.5 FEM by WD

PM2.5

Avg PM2.5
20

Figure 2.13: MLK PM2.5 Concentrations by Wind Direction (WD) Bar Chart 

This supports the interpretation that while both MLK and Chester are impacted by regional transport 

(southwest), Chester also shows significant impact from the northeast, probably reflecting local sources. 

Further examination of transport and trajectories are discussed in section 3. 

2.6 Speciation and “SANDWICH” Analysis

EPA guidance also discusses the use of PM2.5 compositional analysis through use of speciated data from 

the chemical speciation network (CSN) and Improve networks. While MLK has CSN speciation data 

from 2002 through 2012, the Chester PA CSN speciation monitoring ended after 2009. Therefore, only 

2009 speciated data was used to examine similarities and differences between the two sites as well as a 

regional background at Brigantine NJ’s IMPROVE site (Interagency Monitoring of Protected Visual 

Environments). The EPA also recommends the use of the SANDWICH method to compare CSN and 

IMPROVE data.

Table 2.6 shows the 2009 speciated SANDWICH (Sulfate, Adjusted Nitrate, Derived Water, Inferred 

Carbon Hybrid) data for each site as average μg/m3 mass concentrations.

Table 2.6: 2009 Speciated SANDWICH Data

Year Site Name

SANDWICH 

Sulfate 

SANDWICH 

Nitrate 

SANDWICH 

Organic 

Carbon 

SANDWICH 

Elemental 

Carbon 

SANDWICH 

Crustal 

2009 Chester 3.3 2.2 2.6 0.9 0.4

2009 MLK 5.4 1.4 2.9 0.7 0.5

2009 Brigantine 3.8 0.4 1.7 0.3 0.5

Figure 2.14, Figure 2.15, and Figure 2.16 are pie charts with the data in Table 2.6 shown as percentages of 

total PM2.5 mass. The rural Brigantine background site is dominated by transport as shown by the high 

percentage of sulfates. The MLK site shows a combination of transport and local sources as shown by the 

slightly lower percentage of sulfates and higher percentage of nitrates and organic carbon, while the 

Chester site shows even stronger local source impact as seen by the lower sulfate and higher nitrate, 

organic carbon and elemental carbon components. 

0.00

5.00

10.00

15.00

20.00

0-20

21-4041-6061-80

81-100

101-120121-140141-160161-180181-200201-220221-240241-260261-280281-300301-320321-340341-360

MLK PM2.5 FEM by WD

PM2.5 Avg PM2.5
21

Figure 2.14: Brigantine Speciated SANDWICH

Figure 2.15: MLK Speciated SANDWICH

57%

6%

25%

5%

7%

Brigantine 2009 SANDWICH

Sulfates

Nitrates

Organic Carbon

Elemental Carbon

Crustal

49%

13%

27%

6% 5%

MLK 2009 SANDWICH 

Sulfates

Nitrates

Organic Carbon

Elemental Carbon

Crustal
22

Figure 2.16: Chester Speciated SANDWICH

EPA guidance also discusses the use of this SANDWICH data to estimate the urban excess by subtracting 

the rural site background concentrations (Brigantine) from the urban site concentrations (MLK and 

Chester). Table 2.7 shows the urban excess calculated values for MLK and Chester for 2009.

Table 2.7: MLK and Chester vs. Brigantine Urban Excess

Sulfates Nitrates

Organic 

Carbon

Elemental 

Carbon Crustal

MLK – Brigantine 1.6 1.0 1.2 0.4 0.0

Chester -

Brigantine -0.5 1.8 0.9 0.6 -0.1

Figure 2.17 is a graphical presentation of the data in Table 2.7, which shows the speciated data and urban 

excess calculations support the different nature of the PM2.5 concentrations between MLK and Chester;

the Chester site shows more local source influence (greater excess in the nitrate and elemental carbon 

fractions) compared to MLK urban excess (sulfates and organic carbon).

35%

23%

28%

10%

4%

Chester 2009 SANDWICH 

Sulfates

Nitrates

Organic Carbon

Elemental Carbon

Crustal
23

Figure 2.17: MLK and Chester vs. Brigantine Urban Excess

Trends in PM2.5 composition at the MLK DE site are shown in Figure 2.18 using speciation data (nonSANDWICH). The most significant decrease over time is shown in the sulfate component (associated 

with regional transport) followed by the organic carbon, ammonium and nitrate fractions. Equivalent data 

from the Chester site was not available after 2009 and is therefore not included here.

Figure 2.18: MLK non-SANDWICH data

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Sulfates Nitrates Organic 

Carbon

Elemental 

Carbon

Crustal

Diff in ug/m3

2009 SANDWICH - Calculated Urban 

Excess

Chester MLK

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

ug/m3

MLK PM2.5 Speciation Trends

Sulfate Nitrate Ammonium EC OC Crustal
24

2.7 Chester Monitor (Delaware County, PA)

As discussed previously, the ambient data analyses indicate that the Chester monitoring site likely has 

significant impact from local sources. Local impact was indicated by 1) the Chester monitor deviating 

significantly from the downward trend of the other CBSA monitors, 2) the increasing difference with time 

between concentrations at MLK and Chester, 3) the more pronounced higher average concentrations when 

winds are from specific directions, and 4) the analysis of speciated data. 

Delaware notes that the Chester monitor is located near the Delaware River waterfront in a heavily 

industrialized area. About 2-miles to the southwest is the Marcus Hook Petroleum refinery, and about 3-

miles to the northeast is Exelon’s Eddystone Generating Station, and there are many other heavy 

industrial sources in this 5-mile stretch between this refinery and power plant. 

Figure 2.19 illustrates the magnitude of the point sources within 0-10 km of the Chester monitor. Figure 

2.19 shows that there are significant point source emissions close to the Chester monitor, and that 

emissions decrease significantly with distance from the Chester monitor, based upon 5 kilometer 

increments.

7,8

 

Figure 2.19: 2011 Points Source Emissions vs. Distance from Chester Monitor

Delaware also notes that the Chester monitor is located on an unpaved area within the fence line of the

Evonik Corporation (see Picture 1). Evonik manufactures silica from sodium silicate using spray dryers, 

silos, granulator system, and packaging system, and is a significant source of direct PM2.5 emissions.

 7 DAQ believes regional factors play a bigger role beyond 15 km, so the evaluation only involved 0-15 km. 8 The 5 km cutoff captured only facilities located in Delaware County, PA.

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

NOX SO2 PM25 VOC NH3

TPY

5 km

>5-10 km

>10-15 km
25

Picture 1: Chester Monitor Located Within the Fence Line of Evonik Corporation 

Given that the air quality analysis and a physical evaluation of the Chester monitor indicates that the 

monitor is significantly influenced by local sources, Delaware does not believe that data from this monitor 

is appropriate for use in setting nonattainment boundaries that encompass any area broader than the 

footprint of such local sources.

2.8 Summary of Air Quality Analysis 

In summary, this ambient air quality analysis indicates that all areas of Delaware are monitoring PM2.5

concentrations that are well below the NAAQS, and that two nearby sites in Pennsylvania are currently 

monitoring PM2.5 concentrations that exceed the annual average PM2.5 NAAQS. This analysis indicates 

that the air quality in New Castle County is different than the air quality at the two Pennsylvania sites, and 

the air quality analysis supports not associating any part of Delaware with those two areas.

• The New Garden site in Chester County data is typical of a site dominated by regional transport as 

shown by the seasonal and annual trends analysis. The change in monitoring method from the 

FRM to an FEM appears to have introduced a high bias into recent design values. Returning that 

site to the FRM appears to be returning data from that site to trends that are expected, and that 

follow the trends of other sites within the Philadelphia CBSA that are below the annual average 

NAAQS.

• The Chester site in Delaware County is significantly impacted by local sources as shown by 

ambient air quality trends and seasonal patterns, evaluation of high concentration days, speciation 

data analysis (SANDWICH and urban excess calculations), and emissions vs. distance (Figure 

2.19). The Chester site is therefore not representative of the larger Philadelphia CBSA. 
26

Examination of the specific site characteristics also indicates high potential for nearby source 

impact.

Delaware concludes from this ambient air quality analysis that the New Garden and Chester monitoring 

sites are not representative of the larger Philadelphia CBSA, and that no part of Delaware, including New 

Castle County, should be designated as nonattainment due to the air quality in any nearby area.
27

3 METEOROLOGY (WEATHER/TRANSPORT PATTERNS) 

3.1 General Comments

EPA recommends that states consider meteorology in areas included versus excluded from the 

nonattainment area, as one of the factors in determining appropriate nonattainment area boundaries.

Given that monitoring data indicates all areas of Delaware are attaining the PM2.5 standard, this analysis 

focuses on how meteorology may link Delaware to any nearby nonattainment area that the EPA may 

associate with Delaware. 

3.2 Trajectory Cluster Analysis

Back trajectories provide information on the origins of air mass and often used in air pollution analysis. 

Cluster analysis groups similar air masses originating from similar geographic regions, and it can provide 

information on pollution species with similar chemical histories. They are useful in evaluating trends in 

concentrations by air mass. Delaware performed back trajectory cluster analyses for its MLK site in 

Wilmington, and the Chester monitoring site in Pennsylvania, and evaluated if the two sites are impacted 

differently.

Back trajectories needed for the cluster analysis are generated for these two locations with the Hybrid 

Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT).9

 We limit the analysis to the most

recent three years of meteorological data – 2010 to 2012. For our initial analysis we generated 24-hour 

back trajectories for these two locations at 2:00 pm using the EDAS (Eta Data Assimilation System) data 

archives produced by the National Weather Service's National Centers for Environmental Prediction 

(NCEP). 

Additional information on this model can be found on NCEP's website.10 The tools that we used in the 

trajectory cluster analysis are R11 (A Language and Environment for Statistical Computing), and openair 

package for R12,13.

For our initial analysis we plotted back trajectories colored by the PM2.5 concentrations observed at MLK 

DE and Chester PA monitors shown in Figure 3.1. From this figure we can make out that MLK DE and 

Chester PA monitors are impacted differently, that is; different air masses are bringing different levels of 

PM2.5 to these two monitors. Without further analysis, however, we cannot make out what these 

differences are. 

 9 http://ready.arl.noaa.gov/HYSPLIT.php

10 http://www.nco.ncep.noaa.gov/pmb/products/ 11 http://www.R-project.org

12 Carslaw, D.C. and K. Ropkins, (2012). Open air — an R package for air quality data analysis. Environmental Modelling & 

Software. Volume 27-28, 52-61.

Carslaw, D.C. (2013). The open air manual — open-source tools for analyzing air pollution data. Manual for version 0.8-0, 

King’s College London.

13 http://www.openair-project.org
28

Figure 3.1: 24-hour HYSPLIT back trajectories originated at 2:00 pm from MLK DE (top) and 

Chester PA (bottom) monitors for 2010-2012 colored by PM2.5 concentration (μg/m3

)

Back trajectory cluster analysis is likely to explain the differences in impacts at these monitors. For this 

analysis we generated 24-hour back trajectories at 3-hour intervals starting at hour 0. We chose to lump 

the trajectories into six clusters. To simplify the analysis we chose to display the mean trajectories for 

each of the clusters, and they are shown in Figure 3.2. In general, clusters 1 through 4 seem to represent 

flows from west, south-west or north-west directions, whereas clusters 5 and 6 from north-east/east and 

east. The directions of the clusters can change significantly from year to year as noticed in Figure 3.2. 

The mean cluster paths, although they can explain the origins of the clusters, cannot explain how the 

PM2.5 concentrations vary from cluster to cluster and how they vary temporally.
29

Figure 3.2: Six clusters to back trajectories at MLK DE (top) and Chester PA (bottom) monitors 

for 2010-2012 showing the mean trajectory for each cluster

To further explain the differences in the mean cluster paths, we analyzed how the PM2.5 concentrations 

vary by cluster and by month. In order to accomplish this, we merged the cluster data with 24-hour PM2.5

measurements at MLK DE and Chester PA; this makes it possible to identify the data by cluster size. In 

merging the two datasets it is not necessary to retain information for all 24 back trajectory hours; 

therefore we extracted the cluster size for the first hour, which provides PM2.5 data identified by cluster. 

The numbers of trajectories in each cluster by monitor are summarized in Table 3.1.
30

Table 3.1: Numbers of Each Cluster by Monitor

Monitor Year C1 C2 C3 C4 C5 C6

MLK DE 2010 585 558 494 306 429 298

2011 715 700 520 357 302 295

2012 584 448 718 529 339 300

Chester PA 2010 585 581 483 298 433 289

2011 693 685 549 350 315 297

2012 557 438 738 543 343 300

We notice that for the MLK DE monitor the sequence of dominant clusters in 2010 is 1, 2, 3, 5, 4, and 6; 

in 2011 it is 1, 2, 3, 4, 5, and 6; in 2012 it is 3, 1, 4, and 2, followed by 5 and 6. We also notice the same 

behavior at the Chester PA monitor. Although the dominant clusters vary from year to year (from west, 

north-west, south-west, and south), they are the same for both the monitors.

The analysis of how the PM2.5 concentrations vary temporally by cluster is more meaningful. A graphical 

representation of the variation in the mean PM2.5 concentrations by month and hour of the day at both the 

monitors is displayed in Figure 3.3, Figure 3.4, and Figure 3.5. 

Although the dominant clusters are the same for both the monitors, the differences in temporal behavior 

are clearly evident in these figures. For example, in year 2010 cluster 1 (north-west) at MLK DE is 

impacted more in the winter and summer months while cluster 1 at Chester PA monitor is impacted more 

in the winter months; furthermore, morning and afternoon differences in PM2.5 variations are also evident, 

which is a sign of local, rather than regional, impacts at the Chester PA monitor. Similar temporal 

differences are also observed in clusters 3, 4 and 5. Clusters 5 and 6 (easterly flows) show somewhat 

different behavior; in winter the Chester PA monitor is impacted more than the MLK DE monitor. In 

general in winter months the Chester PA monitor shows more variation in PM2.5 concentrations in all the 

clusters, which is a sign of local impacts.
31

Figure 3.3: Variation of PM2.5 by month and hour of the day by wind direction cluster at MLK DE 

(top) and Chester PA (bottom) monitors for 2010

The sequence of dominant clusters at both the monitors in 2011 is the same. The behavior in variation of 

PM-2.5 concentrations by cluster in 2011 is similar to that observed for 2010.
32

Figure 3.4: Variation of PM2.5 by month and hour of the day by wind direction cluster at MLK DE 

(top) and Chester PA (bottom) monitors for 2011

The sequence of dominant clusters in 2012 is the same at both the monitors. The behavior in variation of 

PM-2.5 concentrations by cluster in 2012 is similar to that observed in 2010 and 2011.
33

Figure 3.5: Variation of PM2.5 by month and hour of the day by wind direction cluster at MLK DE 

(top) and Chester PA (bottom) monitors for 2012

3.3 Summary of Trajectory Cluster Analysis 

In this analysis for three years of meteorology, we noticed that the dominant clusters are the same for both 

the monitors. Between the two monitors, we witnessed temporal differences in PM2.5 concentrations from 

cluster to cluster. In the morning hours the Chester PA monitor shows higher PM2.5 concentrations than 

the MLK DE monitor, and also in winter months the Chester PA monitor shows more variation in PM2.5

concentrations in all the clusters. These observations demonstrate that while both the monitors are 

impacted by regional sources, the Chester PA monitor is impacted more by local sources when compared 

to the MLK DE monitor.
34

4 EMISSIONS AND EMISSIONS-RELATED DATA 

As in past PM2.5 designations, EPA will be evaluating the entire Philadelphia CBSA, plus adjacent 

counties (CBSA+) that may contribute to a violation. Thus, EPA recommends that states consider 

emissions potentially included versus excluded from the CBSA nonattainment area as one of the factors in 

determining appropriate nonattainment area boundaries. 

4.1 2011 EPA National Emissions Inventory 

The latest inventory available is the 2011 National Emissions Inventory (NEI), version 1. The 2011 NEI

tons per year (tpy) emission data for counties in the Philadelphia CBSA+ are provided below in Table 

4.1.

14 The data shows that in 2011, New Castle County total PM2.5-related pollutant emissions were 

ranked 10th.

15

Table 4.1: 2011 NEI Philadelphia CBSA+

State County NH3

NH3 

Rank NOX

NOX 

Rank PM25

PM25

Rank SO2

SO2 

Rank VOC

VOC 

Rank SUM

SUM 

Rank

PA York 3495 3 33810 1 3758 2 26590 1 14024 5 81677 1

PA Lancaster 15753 1 13881 9 4107 1 1802 11 13584 6 49127 2

PA Philadelphia 801 9 22394 2 2722 4 2788 5 17548 1 46254 3

PA Northampton 614 17 14074 8 2274 7 20024 2 5404 20 42390 4

PA Berks 4095 2 14390 7 3023 3 6140 4 12848 8 40495 5

PA Montgomery 779 10 17275 4 2508 6 2522 6 15308 4 38393 6

PA Delaware 595 18 17964 3 2579 5 6559 3 10166 12 37863 7

NJ Middlesex 526 20 14766 6 1843 11 771 17 16651 2 34558 8

PA Bucks 1024 7 13277 10 1965 10 2040 9 15477 3 33783 9

DE New Castle 922 8 15866 5 2099 8 2383 7 11469 10 32739 10

PA Chester 1906 5 12177 11 2002 9 2178 8 10454 11 28717 11

NJ Monmouth 740 12 10365 12 1307 16 670 18 12541 9 25624 12

NJ Ocean 335 25 7972 17 1397 15 479 22 13185 7 23367 13

PA Lehigh 620 16 8921 13 1398 14 1323 14 9748 14 22010 14

NJ Burlington 556 19 8448 15 1405 13 525 21 9981 13 20915 15

NJ Camden 244 28 8660 14 1772 12 611 19 9203 15 20490 16

NJ Gloucester 362 24 8015 16 1113 18 1366 13 8940 16 19796 17

NJ Mercer 254 27 7513 18 1260 17 948 15 7560 17 17535 18

DE Kent 2462 4 5673 21 922 21 1839 10 4298 23 15193 19

NJ Somerset 264 26 5960 20 665 23 241 28 7015 19 14145 20

NJ Atlantic 241 29 4905 22 900 22 425 24 7062 18 13534 21

MD Harford 495 21 6169 19 945 20 525 20 5163 21 13298 22

 14 Paved road dust emissions were not included in the summaries due to inconsistencies in data (e.g. Philadelphia County had 

2011 NEI emissions of 17 tpy of PM2.5 from paved road dust while New Castle County had 408 tpy). Wildfires were also 

removed, since they are not an anthropogenic source and uncontrollable. They were also calculated by EPA using satellites, 

which do not match DAQ’s estimates (EPA 502 tpy vs. DE 20 tpy of PM2.5). Biogenic emissions are also not included in any 

of the emission tables in this TSD.

15 Due to the EME Homer City vs. EPA court decision, VOC and ammonia are required to be considered as precursors. 

Henceforth, the “SUM” of all PM2.5-related pollutants will be used as the final indicator of relative rankings (NOTE: Delaware 

could not perform a weighted emissions score due to lack of recent speciated data for each county in the CBSA). 
35

State County NH3

NH3 

Rank NOX

NOX 

Rank PM25

PM25

Rank SO2

SO2 

Rank VOC

VOC 

Rank SUM

SUM 

Rank

NJ Cumberland 459 22 4078 23 1081 19 792 16 4888 22 11299 23

MD Cecil 651 15 3653 24 589 25 323 27 2788 26 8005 24

NJ Salem 708 14 3239 26 453 28 1405 12 2122 27 7926 25

NJ Hunterdon 450 23 3446 25 434 29 328 25 3139 24 7797 26

MD Queen Anne's 1897 6 2943 27 626 24 449 23 1727 28 7643 27

NJ Warren 710 13 2622 28 521 26 328 26 3010 25 7192 28

MD Kent 744 11 1026 29 487 27 204 29 1215 29 3675 29

** Bold font indicates those counties which are part of the Philadelphia CBSA

Table 4.2 shows only the Philadelphia CBSA counties, and that in 2011, New Castle County’s total 

PM2.5- related pollutant emissions were ranked No. 5th (down from 1st in 2002) and barely above 

Delaware County. Furthermore, although New Castle’s emissions are about the same as Delaware 

County, the closest DE monitor to the Chester monitor in Delaware County is Bellefonte (~8 mi.), with a 

2010-2012 DV of only 9.8 μg/m3. This is significantly less than the Chester DV of 13.1 μg/m3, leading 

Delaware to conclude that local emissions significantly influence the Chester monitor. Details on how 

New Castle compares with other counties’ emission reductions are discussed in section 4.3.

Table 4.2: 2011 NEI Philadelphia CBSA

State County NH3

NH3 

Rank NOX

NOX 

Rank PM25

PM25

Rank SO2

SO2 

Rank VOC

VOC 

Rank SUM

SUM 

Rank

PA Philadelphia County 801 4 22394 1 2722 1 2788 2 17548 1 46254 1

PA Montgomery County 779 5 17275 3 2508 3 2522 3 15308 3 38393 2

PA Delaware County 595 7 17964 2 2579 2 6559 1 10166 6 37863 3

PA Bucks County 1024 2 13277 5 1965 6 2040 6 15477 2 33783 4

DE New Castle County 922 3 15866 4 2099 4 2383 4 11469 4 32739 5

PA Chester County 1906 1 12177 6 2002 5 2178 5 10454 5 28717 6

NJ Burlington County 556 8 8448 8 1405 8 525 10 9981 7 20915 7

NJ Camden County 244 11 8660 7 1772 7 611 9 9203 8 20490 8

NJ Gloucester County 362 10 8015 9 1113 9 1366 7 8940 9 19796 9

MD Cecil County 651 6 3653 11 589 11 323 11 2788 11 8005 11

4.2 Emissions Related Data

4.2.1 Population

EPA recommends that states consider the population density and the degree of urbanization in areas 

included versus excluded from the nonattainment area as one of the factors in determining appropriate 

nonattainment area boundaries. Population, growth rates, population densities and rankings for the 

Philadelphia CBSA and surrounding counties (CBSA+) are presented in Table 4.3, and shows that New 

Castle County ranks:

• 7th for 2010 population for the CBSA+

• 12th in population growth between 2000-2010 for the CBSA+

• 7th in 2010 population density CBSA+
36

• 5th for 2010 population for the CBSA

• 4th in population growth between 2000-2010 for the CBSA

• 5th in 2010 population density CBSA

Table 4.3: 2000-2010 Population Statistics - Philadelphia CBSA+

State County 20001 20102

2010 

Rank

CBSA

Rank

% 

Growth

CBSA+

Rank

CBSA

Rank

Sq. 

Miles

Pop. 

Density

CBSA+

Rank

CBSA

Rank

PA Philadelphia 1,517,562 1,526,006 1 1 1% 25 8 135 11,304 1 1

PA Montgomery 749,409 799,874 2 2 7% 14 5 483 1,656 4 4

NJ Monmouth 615,253 630,380 3 2% 22 472 1,336 6

PA Bucks 597,548 625,249 4 3 5% 19 7 607 1,030 8 6

NJ Ocean 510,950 576,567 5 13% 4 636 907 10

PA Delaware 551,722 558,979 6 4 1% 23 8 184 3,038 2 2

DE New Castle 500,294 538,479 7 5 8% 12 4 426 1,264 7 5

PA Lancaster 470,783 519,445 8 10% 9 949 547 16

NJ Camden 507,075 513,657 9 6 1% 24 222 2,314 3 3

PA Chester 433,208 498,886 10 7 15% 3 2 756 660 13 8

NJ Burlington 423,329 448,734 11 8 6% 16 6 805 557 14 9

PA Berks 373,712 411,442 12 10% 10 859 479 18

NJ Mercer 350,773 366,513 13 4% 20 226 1,622 5

PA Lehigh 311,746 349,497 14 12% 6 347 1,007 9

PA Northampton 267,446 297,735 15 11% 8 374 796 12

NJ Gloucester 255,946 288,288 16 9 13% 5 3 325 887 11 7

NJ Atlantic 253,210 274,549 17 8% 11 561 489 17

MD Harford 218,914 244,826 18 12% 7 440 556 15

DE Kent 126,771 162,310 19 28% 1 591 275 24

NJ Cumberland 146,454 156,898 20 7% 13 489 321 20

NJ Hunterdon 122,110 128,349 21 5% 18 430 298 22

NJ Warren 102,383 108,692 22 6% 15 358 304 21

MD Cecil 85,964 101,108 23 10 18% 2 1 348 291 23 10

NJ Cape May 102,323 97,265 24 -5% 26 255 381 19

NJ Salem 64,272 66,083 25 3% 21 338 196 25

MD Kent 19,201 20,197 26 5% 17 279 72 26

1 The April 1, 2000 Population Estimates base reflects changes to the Census 2000 population from the Count Question Resolution program, 

legal boundary updates, and other geographic program revisions."

2 The data source for April 1, 2010 is the 2010 Census count. Note: All geographic boundaries for the 2000-2010 intercensal estimates are 

defined as of January 1, 2010.

Citation 2000-2010 data: Table 1. Intercensal Estimates of the Resident Population for Counties of Delaware: April 1, 2000 to July 1, 

2010 (CO-EST00INT-01-10). Source: U.S. Census Bureau, Population Division, Release Date: September 2011

http://www.census.gov/popest/data/intercensal/county/CO-EST00INT-01.html

** Bold font indicates those counties which are part of the Philadelphia CBSA

Based on population vs. air quality data, Delaware believes that ambient concentrations of PM2.5 do not 

necessarily correlate with population parameters. For instance, Philadelphia County is not violating the 

NAAQS, while its population and population density is almost three and four times greater, respectively, 

than Delaware County (nonattainment). Furthermore, the highest Philadelphia County design value is 

only 11.0 μg/m3 while Delaware County’s is 13.1 μg/m3

, a difference of 3.1 μg/m3; or about 25% of the 

NAAQS. Similarly, Camden County NJ has almost twice the population density as New Castle, DE yet 

Camden’s 2012 DVs is only 9.5 μg/m3, compared to New Castle’s highest DV of 10.4 μg/m3.
37

To further evaluate the relationship of population vs. DVs, Delaware obtained a listing of the top 25 

CBSAs by population from EPA’s website, and then looked at the attainment status using 2009-2011 

DVs. Delaware performed a statistical analysis of population vs. design values and found insignificant 

correlation between the two datasets (r = 0.31).

16 Table 4.4 ranks the top CBSAs by population with 

their corresponding 2009-2011 DVs. 

Table 4.4: Top 25 CBSA17 - Attainment Status (2009-2011 DVs)

CBSA Name Population 2010 2009-2011 DV

New York-Northern New Jersey-Long Island, NY-NJ-PA 18,919,649 11.9

Los Angeles-Long Beach-Santa Ana, CA 12,844,371 13.9

Chicago-Joliet-Naperville, IL-IN-WI 9,472,584 12.7

Dallas-Fort Worth-Arlington, TX 6,400,511 10.6

Houston-Sugar Land-Baytown, TX 5,976,470 12.4

Philadelphia-Camden-Wilmington, PA-NJ-DE-MD 5,971,589 13.1

Washington-Arlington-Alexandria, DC-VA-MD-WV 5,609,150 10.8

Miami-Fort Lauderdale-Pompano Beach, FL 5,578,080 7.5

Atlanta-Sandy Springs-Marietta, GA 5,286,296 13.2

Boston-Cambridge-Quincy, MA-NH 4,559,372 10.2

San Francisco-Oakland-Fremont, CA 4,343,381 9.9

Detroit-Warren-Livonia, MI 4,290,722 11.6

Riverside-San Bernardino-Ontario, CA 4,245,005 16.2

Phoenix-Mesa-Glendale, AZ 4,209,070 9.9

Seattle-Tacoma-Bellevue, WA 3,447,886 8.3

Minneapolis-St. Paul-Bloomington, MN-WI 3,285,913 9.7

San Diego-Carlsbad-San Marcos, CA 3,105,115 13.1

St. Louis, MO-IL 2,814,722 13.1

Tampa-St. Petersburg-Clearwater, FL 2,788,151 7.8

Baltimore-Towson, MD 2,714,546 11.1

Denver-Aurora-Broomfield, CO 2,554,569 8.1

Pittsburgh, PA 2,357,951 13.7

Portland-Vancouver-Hillsboro, OR-WA 2,232,896 7.9

Sacramento--Arden-Arcade--Roseville, CA 2,154,583 10

San Antonio-New Braunfels, TX 2,153,891 9.2

Correlation of Population vs. Design Values 0.31

Setting the low correlation score of 0.31 (population vs. DV) aside for the moment, Delaware is well 

aware that some source categories utilize population as the activity data in non-point (area) source 

emission calculations. Based on previous EPA designation letters to Delaware, this is one of the main 

reasons EPA includes population as one of the 5-factor analysis. However, in the case of Delaware 

emissions, the only area source categories in the 2011 NEI that are strictly population-dependent are: 

 16 An r score of 0.75 or higher would suggest a correlation, therefore a score of 0.31 is highly non-correlated. 17 http://www.city-data.com/top1.html
38

• Consumer and Commercial Products,

• Industrial Adhesives,

• AIM Coatings, and

• Commercial Cooking 

• Stage I and Stage 2 

• Dry Cleaning

Of these source categories, all but commercial cooking exclusively emits VOC, which are already strictly 

controlled via reasonably available control technology (RACT) under 7 DE Admin. Code 1124. The 

commercial cooking category includes both PM2.5 and VOC which are not economically conducive to 

emission control (discussed in more detail in Section 4.4). Furthermore, due to low stack heights and 

flow rates, Delaware considers VOC and PM2.5 from commercial cooking to be localized, and not a 

regional contributor. 

There are also some categories that rely on occupied housing numbers, which are indirectly related to 

human population. The residential open burning category and residential wood combustion are the two 

categories which use housing data. Delaware already strictly regulates open burning through 7 DE 

Admin. Code 1113, and woodstoves are regulated by the EPA under New Source Performance Standards. 

Either way, due to low stack heights and flow rates from fireplaces and ground-level open burning, 

Delaware considers emission contribution from these categories to be localized and not contributors to 

PM2.5 concentrations at the Chester monitor. 

Figure 4.1 plots New Castle County’s population against New Castle DVs. This figure illustrates that 

population is not well correlated with air quality data. 

Figure 4.1: NCC 3-year Rolling DVs vs. NCC Population (over 10 years)

In summary, Delaware believes population and related criteria are not suitable as a tool in making 

boundary determinations for New Castle County, or at the very least should be low priority in EPA 

boundary considerations. 

490,000

500,000

510,000

520,000

530,000

540,000

550,000

10

11

12

13

14

15

16

17

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

ug/m3

YEAR

Population vs. PM25 DVs

New Castle DV (μg/m3) Population
39

4.2.2 Expected growth 

Growth in New Castle County is likely to be regulated beyond most other areas because of Delaware’s 

existing environmentally protective programs. These include Delaware’s New Source Review (NSR) 

program, Delaware’s Coastal Zone Program, where offsets are required for any increase in emissions (no 

de minimis), and the Livable Delaware initiative which is designed to promote smart growth principles. 

Table 4.5 shows the 2010 and 203518 populations, rankings and growth rates of counties within the 

CBSA/CBSA+. It can be seen that of the CBSA+ nonattaining counties, Chester and Delaware are 

ranked 8th and 10th for population growth in 2035, and 7th and 25th for growth rate rankings, respectively. 

Meanwhile, New Castle County ranks 9th and 21st for 2035 population and 2035 growth rate, respectively. 

Thus, while all three nearby counties have similar rankings in 2010, New Castle County has one of the 

lowest projected growth rates for 2035. Note that in the CBSA, New Castle is ranked 7th out of 10 

counties. Consequently, New Castle future emission increases due to population can reasonably be 

expected to be minimal. 

Table 4.5: 2010-2035 Population, Growth and Rankings – Philadelphia CBSA+

State County ** 2010 2035 (1)

CBSA+

Rank

Absolute 

Change

2035

Growth 

Rate

CBSA+

Rank

CBSA

Rank

PA Lehigh 349,497 833,441 3 483,944 58% 1

MD Cecil 101,108 156,133 21 55,025 35% 2 1

NJ Ocean 576,567 776,300 4 199,733 26% 3

NJ Atlantic 274,549 357,570 17 83,021 23% 4

PA Northampton 297,735 384,873 15 87,138 23% 5

NJ Gloucester 288,288 369,370 16 81,082 22% 6 2

PA Chester 498,886 622,500 8 123,614 20% 7 3

NJ Warren 108,692 134,200 23 25,508 19% 8

DE Kent 162,310 199,065 19 36,755 18% 9

PA Lancaster 519,445 632,595 7 113,150 18% 10

NJ Burlington 448,734 541,200 11 92,466 17% 11 4

PA Bucks 625,249 753,780 5 128,531 17% 12 5

MD Harford 244,826 292,620 18 47,794 16% 13

NJ Cape May 97,265 116,010 24 18,745 16% 14

MD Kent 20,197 23,850 26 3,653 15% 15

NJ Hunterdon 128,349 147,800 22 19,451 13% 16

NJ Monmouth 630,380 717,900 6 87,520 12% 17

NJ Cumberland 156,898 176,060 20 19,162 11% 18

PA Montgomery 799,874 894,140 2 94,266 11% 19 6

PA Berks 411,442 459,221 13 47,779 10% 20

DE New Castle 538,479 598,312 9 59,833 10% 21 7

NJ Mercer 366,513 403,980 14 37,467 9% 22

NJ Salem 66,083 72,710 25 6,627 9% 23

NJ Camden 513,657 524,680 12 11,023 2% 24 8

 18 The year 2035 was chosen because States have at least until 2020 to achieve compliance with the 2012 NAAQS, and 

subsequent maintenance plans typically address emissions and control measures, such as mobile budgets maintenance at least 

15 years later or more.
40

State County ** 2010 2035 (1)

CBSA+

Rank

Absolute 

Change

2035

Growth 

Rate

CBSA+

Rank

CBSA

Rank

PA Delaware 558,979 559,960 10 981 0% 25 9

PA Philadelphia 1,526,006 1,480,000 1 -46,006 -3% 26 10

Delaware 2010-2035 projections data: Wilmington Area Planning Council, WILMAPCO 2012 Inter-Regional Report. 

http://www.wilmapco.org/wilmapco-council/

** Bold font indicates those counties which are part of the Philadelphia CBSA

4.2.3 Traffic and commuting patterns 

Table 4.6 shows that New Castle County ranks 5th (on average) for 1) Number of residents commuting to 

any violating counties, 2) Percent Commuting to any violating counties, 3) Number commuting into and 

within the CBSA/CBSA+ and 4) Percent commuting into and within CBSA. Of particular importance is 

the data showing only 6.2% of Delaware commuters going to either Delaware or Chester Counties. And, 

although this presents evidence that Delaware citizens/commuters contribute some pollution via cars to air 

quality monitored in each of those Counties, it is small in relation to the previously discussed 

contributions of local point sources, particularly the Chester monitor in Delaware County19 as discussed 

in section 2.7.

Table 4.6: CBSA+ Commuting Patterns 

State County**

Number 

commuting 

to any 

violating 

counties

CBSA+

Rank

Percent 

Commuting 

to any 

violating 

counties

CBSA+

Rank

Number 

commuting 

into and 

within 

CBSA+

CBSA+

Rank

Percent 

commuting 

into and 

within 

CBSA+

CBSA+

Rank

CBSA 

Rank

PA Chester 172,644 1 70.9% 1 232,571 6 95.6% 4 1

PA Delaware 157,218 2 60.9% 2 254,548 4 98.6% 1 2

PA Montgomery 37,819 3 9.4% 3 387,702 2 96.9% 3 3

PA Philadelphia 25,038 4 4.2% 6 588,694 1 98.4% 2 4

DE New Castle 15,794 5 6.2% 4 243,130 5 94.7% 5 5

PA Berks 8,687 6 4.6% 5 26,410 10 13.9% 12

PA Lancaster 8,421 7 3.4% 7 11,661 14 4.8% 19

PA Bucks 5,177 8 1.7% 11 270,365 3 87.5% 8 6

NJ Gloucester 4,226 9 3.1% 8 123,031 9 89.8% 7 7

NJ Camden 2,922 10 1.2% 12 222,034 7 93.4% 6 8

NJ Burlington 1,751 11 0.8% 13 174,516 8 81.5% 9 9

MD Cecil 1,363 12 2.9% 9 14,359 11 30.2% 11 10

PA Lehigh 706 13 0.4% 14 12,057 13 7.6% 16

NJ Salem 604 14 2.1% 10 10,736 15 37.1% 10

PA Northampton 359 15 0.3% 18 4,813 20 3.6% 20

NJ Mercer 309 16 0.2% 20 13,545 12 8.3% 15

DE Kent 294 17 0.4% 16 9,635 16 13.8% 13

 19 Based on trends and changing their monitor from FEM to FRM, DAQ believes the New Garden monitor in Chester County 

PA is likely to be attainment based upon 2011-2013 data.
41

State County**

Number 

commuting 

to any 

violating 

counties

CBSA+

Rank

Percent 

Commuting 

to any 

violating 

counties

CBSA+

Rank

Number 

commuting 

into and 

within 

CBSA+

CBSA+

Rank

Percent 

commuting 

into and 

within 

CBSA+

CBSA+

Rank

CBSA 

Rank

NJ Atlantic 265 18 0.2% 19 8,953 17 7.2% 17

MD Harford 231 19 0.2% 21 1,764 23 1.4% 23

NJ Cumberland 213 20 0.3% 17 6,522 19 10.6% 14

NJ Monmouth 196 21 0.1% 23 2,842 21 1.1% 24

NJ Ocean 145 22 0.1% 24 6,902 18 3.0% 22

NJ Warren 71 23 0.1% 22 430 25 0.8% 25

MD Kent 40 24 0.4% 15 670 24 7.1% 18

NJ Hunterdon 21 25 0.0% 25 2,012 22 3.3% 21

MD Queen Anne's 0 26 0.0% 26 0 26 0.0% 26

NJ Middlesex 0 26 0.0% 27 0 26 0.0% 26

NJ Somerset 0 26 0.0% 28 0 26 0.0% 26

PA York 0 26 0.0% 29 0 26 0.0% 26

** Bold font indicates those counties which are part of the Philadelphia CBSA

4.2.4 Vehicle Miles Traveled 

Table 4.7 shows that while New Castle County is ranked 4th in the CBSA+ for 2010 vehicle miles 

traveled (VMT), relative to 2002 vehicle miles traveled (VMT), New Castle County had the 18th lowest 

growth rate at negative 3%, and was ranked 8th out of 10 Counties in the Philadelphia CBSA.

Table 4.7: CBSA+ 2002-2010 Vehicle Miles Traveled and Rankings

State County**

2002 (million 

VMT)

2010 (million 

VMT)

CBSA+

Rank

% 

Growth

CBSA+

Rank

CBSA 

Rank

PA Montgomery 4,677 6,452 1 38% 1 1

NJ Salem 734 977 25 33% 2

PA Chester 3,128 4,134 7 32% 3 2

NJ Cape May 749 987 24 32% 4

NJ Atlantic 2,236 2,766 14 24% 5

PA Bucks 3,830 4,686 5 22% 6 3

NJ Burlington 3,748 4,449 6 19% 7 4

NJ Monmouth 5,146 6,098 2 18% 8

NJ Gloucester 2,312 2,610 16 13% 9 5

NJ Warren 1,473 1,556 21 6% 10

MD Harford 2,208 2,322 17 5% 11

NJ Ocean 3,641 3,705 10 2% 12

PA Delaware 3,513 3,545 11 1% 13 6

PA Cecil 1,340 1,350 22 1% 14 7

PA Lehigh 2,738 2,720 15 -1% 15

DE Kent 1,633 1,620 20 -1% 16
42

State County**

2002 (million 

VMT)

2010 (million 

VMT)

CBSA+

Rank

% 

Growth

CBSA+

Rank

CBSA 

Rank

PA Lancaster 4,004 3,964 8 -1% 17

DE New Castle 5,338 5,201 4 -3% 18 8

NJ Hunterdon 1,893 1,843 19 -3% 19

NJ Cumberland 1,166 1,115 23 -4% 20

NJ Camden 4,332 3,880 9 -10% 21 9

PA Northampton 2,132 1,871 18 -12% 22

NJ Mercer 3,869 3,286 12 -15% 23

PA Berks 3,952 3,128 13 -21% 24

PA Philadelphia 10,213 5,579 3 -45% 25 10

Data sources: 

2010 non-DE VMT - http://www.epa.gov/airquality/particlepollution/designations/2012standards/techinfo.htm

2002 and 2010 Delaware VMT: http://www.deldot.gov/information/projects/hpms/pages/hpms_2011.shtml

** Bold font indicates those counties which are part of the Philadelphia CBSA

Regardless of the fact that Montgomery County, PA ranks 1st in 2010 VMT, and also 1st in 2002-2010 

VMT growth, the Montgomery County, PA 2012 DV is only 9.8 μg/m3. And, although Delaware county 

VMT has stayed relatively the same since 2002, its 2010-2012 DV remains the highest in the CBSA. 

Therefore, if increasing levels of VMT can result in non-violations, and New Castle VMT growth has 

been negative, Delaware believes EPA should not consider VMT (and thus commuting) as a possible 

reason to include New Castle County in any nonattainment area. 

4.3 Emission Reductions 

4.3.1 General Discussion

Over the past decade Delaware and Regional Planning Organizations have conducted many studies 

relative to visibility and fine particulate matter (PM2.5) concerns.20,21,22,23 The studies included modeling, 

emissions analysis and source contribution assessments. As a result, Delaware learned that sulfate was 

the largest contributor to PM2.5 nonattainment in the eastern United States, followed by nitrates, organic 

compounds and, depending on the location of the monitor to highways and/or point sources, direct PM2.5. 

These studies also reveal that the previous PM2.5 nonattainment status for both Delaware and the 

Philadelphia Combined Statistical Area CSA (Philadelphia-Camden-Wilmington, PA-NJ-DE-MD) was 

caused primarily by a combination of underlying long-range interstate transport of sulfate and nitrates 

from power plants in the Ohio River valley, and local sources of direct PM2.5 (mobile and point). Since 

sulfur dioxide (SO2) and oxides of nitrogen (NOx) are precursors to sulfate and nitrate; SO2 and NOx are 

 20 Contributions to Regional Haze in the Northeast and Mid-Atlantic United States Mid-Atlantic/Northeast Visibility Union 

(MANE-VU) Contribution Assessment, Prepared by NESCAUM for the Mid-Atlantic/Northeast Visibility Union (MANEVU), August 2006

21 A Guide to Mid-Atlantic Regional Air Quality, Mid-Atlantic Regional Air Management Association, October 2005 22 The Nature of the Fine Particle and Regional Haze Air Quality Problems in the MANE-VU Region: A Conceptual 

Description, by NESCAUM Boston, MA November 2, 2006

23 Philip K. Hopke and Eugene Kim, Analysis of Speciation Trends Network Data Measured at the State of Delaware, Center 

for Air Resources Engineering and Science Clarkson University, Potsdam, NY, January 20, 2005
43

the largest pollutants of concern due to regional and long-range transport, while emissions of direct PM2.5

and certain carbonaceous compounds tend to affect air quality more on a local level, particularly onroad 

mobile sources. Thus, it is generally understood that sulfates and nitrates are more regional in nature, 

while direct PM2.5 and volatile organic compounds (VOC) are more locally-oriented. 

All non-trivial Delaware sources of PM2.5-related pollutants are currently well controlled. 

4.3.2 Delaware’s 2012 Point Source Reductions Since 2002

As can be seen in Table 4.8, total 2012 emissions of direct PM2.5 and its precursors from New Castle 

County’s largest point sources24 decreased 87% between 2002 and 2012. This included a massive 99% 

reduction in SO2, followed by a 65% reduction in direct PM2.5, and a 52% decrease of NOx. VOC 

reductions of 54% have taken place since the early 1990s due to Delaware’s ozone nonattainment issues 

over the years. NH3 emissions have been reduced 52%, even though New Castle County emissions of 

ammonia in 2002 from these largest point sources were only 82 tons per year (tpy). 

Table 4.8: New Castle County - Top Point Source Emitters in 2002 and 2012

New Castle Top 

Emitting Facilities NH3 NOx SO2 PM2.5 VOC

Sum of PM2.5 

related Pollutants

2002 2012 2002 2012 2002 2012 2002 2012 2002 2012 2002 2012

Calpine Edge Moor 30 16 3,138 463 9,854 48 517 4 36 33 13,575 564

Calpine Hay Road 0 1 566 696 11 13 3 142 10 45 590 897

DE City Refinery 43 12 3,555 2,083 34,096 304 905 312 829 208 39,428 2,919

DuPont Edgemoor 1 1 35 29 92 21 27 1 83 98 239 150

DuPont Experimental 

Station 3 3 208 176 593 226 37 18 8 11 849 434

Evraz Steel 0 0 125 227 11 40 45 59 67 67 248 393

Formosa 4 6 31 31 0 1 35 15 124 69 194 122

TOTALS 82 39 7,658 3,705 44,658 653 1,569 551 1,157 531 57,126 7,491

2002-2012 % Reduction 52% 52% 99% 65% 54% 87%

4.3.3 CBSA Emission Reductions between 2002 and 2011

Table 4.9, Table 4.10, and Table 4.11 contain emissions data showing the Philadelphia CBSA emissions 

in 2002 and 2011, along with the corresponding emission reductions and rankings. As can be seen from 

the tables, New Castle ranked 1st of the 10 counties in total PM2.5-related emissions during 2002. On the 

other hand, due to the significant control measures Delaware has implemented since 2002, New Castle 

now ranks 5th in total emissions, and more importantly, ranks 1st in total emission reductions. 

 24 2012 emissions ≥ 50 tpy for any PM2.5-related pollutant
44

Table 4.9: Philadelphia CBSA 2002 Emissions and Rank

State County NH3 NOX PM25 SO2 VOC SUM

SUM

Rank

DE New Castle 1940 29995 3920 50155 19917 105926 1

PA Philadelphia 1084 30595 2988 9508 35725 79900 2

PA Montgomery 1450 25686 3642 5171 29971 65920 3

PA Delaware 870 23699 2292 16028 17287 60175 4

PA Bucks 1774 19800 2881 3825 23218 51497 5

PA Chester 2521 18476 3075 5507 17853 47432 6

NJ Burlington 1524 17832 2102 3429 18599 43486 7

NJ Gloucester 1003 14106 1411 7169 16008 39696 8

NJ Camden 1207 14785 1461 1909 16352 35713 9

MD Cecil 530 4669 1019 640 6050 12908 11

Table 4.10: Philadelphia CBSA 2011 Emissions and Rank 

State County NH3 NOX PM25 SO2 VOC SUM Rank

PA Philadelphia 801 22394 2722 2788 17548 46254 1

PA Montgomery 779 17275 2508 2522 15308 38393 2

PA Delaware 595 17964 2579 6559 10166 37863 3

PA Bucks 1024 13277 1965 2040 15477 33783 4

DE New Castle 922 15866 2099 2383 11469 32739 5

PA Chester 1906 12177 2002 2178 10454 28717 6

NJ Burlington 556 8448 1405 525 9981 20915 7

NJ Camden 244 8660 1772 611 9203 20490 8

NJ Gloucester 362 8015 1113 1366 8940 19796 9

MD Cecil 651 3653 589 323 2788 8005 11
45

Table 4.11: Philadelphia CBSA 2002-2011 Reductions and Rankings

State County NH3

NH3 

Rank NOX

NOX 

Rank PM25

PM25

Rank SO2

SO2 

Rank VOC

VOC 

Rank SUM

SUM 

Rank

DE New Castle 1018 1 14129 1 1821 1 47772 1 8448 4 73188 1

PA Philadelphia 283 8 8201 4 266 8 6720 3 18177 1 33646 2

PA Montgomery 671 5 8411 3 1134 2 2649 7 14663 2 27527 3

NJ Burlington 968 2 9384 2 697 5 2904 6 8618 3 22571 4

PA Delaware 275 9 5735 9 -287 10 9469 2 7121 8 22313 5

NJ Gloucester 641 6 6091 8 298 7 5803 4 7068 9 19901 6

PA Chester 615 7 6299 6 1073 3 3329 5 7399 6 18715 7

PA Bucks 750 4 6523 5 916 4 1785 9 7741 5 17715 8

NJ Camden 963 3 6125 7 -311 11 1298 10 7149 7 15224 9

MD Cecil -121 11 1016 11 430 6 317 11 3262 10 4903 11

Figure 4.2 illustrates the emission reductions (“SUM”) from Table 4.11, and it is important to note that 

New Castle County obtained more than double the reductions than the next highest ranking County –

Philadelphia County – and over three times more than Delaware County.

Figure 4.2: Philadelphia CBSA 2002-2011 Reductions and Rankings

0

10000

20000

30000

40000

50000

60000

70000

80000

tons per year 
46

Table 4.12 shows the data in Table 4.11 in terms of percent reductions, with New Castle County being 

number one with a 69% reduction of PM2.5-related pollutants. Again, it is noteworthy that the next 

highest County (Philadelphia) has comparative 42% reductions, and the two nonattaining CBSA counties 

of Chester and Delaware both have only 39% and 37% reductions, respectively. 

Table 4.12: Philadelphia CBSA 2002-2011 Percent Reductions

State County NH3 NOX PM25 SO2 VOC SUM

DE New Castle 52% 47% 46% 95% 42% 69%

NJ Burlington 64% 53% 33% 85% 46% 52%

NJ Gloucester 64% 43% 21% 81% 44% 50%

NJ Camden 80% 41% -21% 68% 44% 43%

PA Philadelphia 26% 27% 9% 71% 51% 42%

PA Montgomery 46% 33% 31% 51% 49% 42%

PA Chester 24% 34% 35% 60% 41% 39%

MD Cecil -23% 22% 42% 49% 54% 38%

PA Delaware 32% 24% -13% 59% 41% 37%

PA Bucks 42% 33% 32% 47% 33% 34%

Figure 4.3 illustrates the data in Table 4.12

Figure 4.3: Philadelphia CBSA 2002-2011 Percent Reductions

0%

10%

20%

30%

40%

50%

60%

70%
47

4.3.4 Philadelphia CBSA and CBSA+ 2002 and 2011 Emissions and Reductions 

Table 4.13, Table 4.14, Table 4.15, and Table 4.16 contain emissions data showing the Philadelphia 

CBSA+ emissions in 2002 and 2011, along with the corresponding emission reductions, rankings and 

percent reductions. As can be seen from tables, New Castle ranked 2nd of the 29 counties in total PM2.5-

related emissions during 2002. However, due to the significant control measures Delaware has 

implemented since 2002, New Castle now ranks 10th in total CBSA+ emissions, and again ranks 1st in 

total emission reductions, as well as in terms of total percent reductions (out of 29 counties). This data 

shows that Delaware has led the Philadelphia CBSA and surrounding counties in developing post-2002 

control measures. As discussed in the next section, either EPA or Delaware has already regulated every 

non-trivial source with reasonable available control technology. 

Table 4.13: Philadelphia CBSA+ 2002 Emissions and Total Rank

State County FIPS NH3 NOX PM25 SO2 VOC

SUM

Rank

PA York 42133 3862 37634 5647 82669 20079 149891 1

DE New Castle 10003 1940 29995 3920 50155 19917 105926 2

PA Northampton 42095 722 24212 3473 58764 10648 97819 3

PA Philadelphia 42101 1084 30595 2988 9508 35725 79900 4

PA Lancaster 42071 16400 19652 4529 3974 25647 70203 5

PA Berks 42011 4610 21748 3585 17595 19341 66880 6

PA Montgomery 42091 1450 25686 3642 5171 29971 65920 7

NJ Middlesex 34023 2032 25931 2193 2117 30993 63267 8

PA Delaware 42045 870 23699 2292 16028 17287 60175 9

NJ Mercer 34021 1012 24978 1369 15508 12719 55585 10

PA Bucks 42017 1774 19800 2881 3825 23218 51497 11

PA Chester 42029 2521 18476 3075 5507 17853 47432 12

NJ Monmouth 34025 1714 17316 1722 1670 24780 47200 13

NJ Burlington 34005 1524 17832 2102 3429 18599 43486 14

NJ Ocean 34029 1214 10120 2363 1074 27598 42369 15

NJ Gloucester 34015 1003 14106 1411 7169 16008 39696 16

NJ Camden 34007 1207 14785 1461 1909 16352 35713 17

PA Lehigh 42077 825 14203 1893 3764 13855 34541 18

NJ Somerset 34035 1100 9970 1732 637 15032 28472 19

NJ Atlantic 34001 832 8152 1080 885 15277 26226 20

DE Kent 10001 2191 10095 1228 4039 6384 23937 21

MD Harford 24025 980 8218 1738 1205 10200 22341 22

NJ Cumberland 34011 644 6865 927 3217 8077 19730 23

NJ Hunterdon 34019 962 6323 1270 613 9024 18193 24

NJ Salem 34033 656 6498 784 5452 4736 18127 25

NJ Warren 34041 706 5006 1119 565 7284 14679 26

MD Cecil 24015 530 4669 1019 640 6050 12908 27

MD Queen Anne's 24035 1550 2780 946 551 3864 9691 28

MD Kent 24029 719 1166 594 386 2356 5221 29
48

** Bold font indicates those counties which are part of the Philadelphia CBSA

Table 4.14: Philadelphia CBSA+ 2011 Emissions and Rankings

State County FIPS NH3 NOX PM25 SO2 VOC SUM Rank

PA York County 42133 3495 33810 3758 26590 14024 81677 1

PA Lancaster 42071 15753 13881 4107 1802 13584 49127 2

PA Philadelphia 42101 801 22394 2722 2788 17548 46254 3

PA Northampton 42095 614 14074 2274 20024 5404 42390 4

PA Berks 42011 4095 14390 3023 6140 12848 40495 5

PA Montgomery 42091 779 17275 2508 2522 15308 38393 6

PA Delaware 42045 595 17964 2579 6559 10166 37863 7

NJ Middlesex 34023 526 14766 1843 771 16651 34558 8

PA Bucks 42017 1024 13277 1965 2040 15477 33783 9

DE New Castle 10003 922 15866 2099 2383 11469 32739 10

PA Chester 42029 1906 12177 2002 2178 10454 28717 11

NJ Monmouth 34025 740 10365 1307 670 12541 25624 12

NJ Ocean 34029 335 7972 1397 479 13185 23367 13

PA Lehigh 42077 620 8921 1398 1323 9748 22010 14

NJ Burlington 34005 556 8448 1405 525 9981 20915 15

NJ Camden 34007 244 8660 1772 611 9203 20490 16

NJ Gloucester 34015 362 8015 1113 1366 8940 19796 17

NJ Mercer 34021 254 7513 1260 948 7560 17535 18

DE Kent 10001 2462 5673 922 1839 4298 15193 19

NJ Somerset 34035 264 5960 665 241 7015 14145 20

NJ Atlantic 34001 241 4905 900 425 7062 13534 21

MD Harford 24025 495 6169 945 525 5163 13298 22

NJ Cumberland 34011 459 4078 1081 792 4888 11299 23

MD Cecil 24015 651 3653 589 323 2788 8005 24

NJ Salem 34033 708 3239 453 1405 2122 7926 25

NJ Hunterdon 34019 450 3446 434 328 3139 7797 26

MD Queen Anne's 24035 1897 2943 626 449 1727 7643 27

NJ Warren 34041 710 2622 521 328 3010 7192 28

MD Kent 24029 744 1026 487 204 1215 3675 29

** Bold font indicates those counties which are part of the Philadelphia CBSA
49

Table 4.15: Philadelphia CBSA+ 2002-2011 Emission Reductions and Rankings

State County FIPS NH3 NOX PM25 SO2 VOC SUM Rank

DE New Castle 10003 1018 14129 1821 47772 8448 73187 1

PA York 42133 367 3824 1889 56079 6055 68214 2

PA Northampton 42095 108 10138 1199 38740 5244 55429 3

NJ Mercer 34021 758 17465 109 14560 5159 38050 4

PA Philadelphia 42101 283 8201 266 6720 18177 33646 5

NJ Middlesex 34023 1506 11165 350 1346 14342 28709 6

PA Montgomery 42091 671 8411 1134 2649 14663 27527 7

PA Berks 42011 515 7358 562 11455 6493 26385 8

NJ Burlington 34005 968 9384 697 2904 8618 22571 9

PA Delaware 42045 275 5735 -287 9469 7121 22312 10

NJ Monmouth 34025 974 6951 415 1000 12239 21576 11

PA Lancaster 42071 647 5771 422 2172 12063 21076 12

NJ Gloucester 34015 641 6091 298 5803 7068 19900 13

NJ Ocean 34029 879 2148 966 595 14413 19002 14

PA Chester 42029 615 6299 1073 3329 7399 18715 15

PA Bucks 42017 750 6523 916 1785 7741 17714 16

NJ Camden 34007 963 6125 -311 1298 7149 15223 17

NJ Somerset 34035 836 4010 1067 396 8017 14327 18

NJ Atlantic 34001 591 3247 180 460 8215 12692 19

PA Lehigh 42077 205 5282 495 2441 4107 12531 20

NJ Hunterdon 34019 512 2877 836 285 5885 10396 21

NJ Salem 34033 -52 3259 331 4047 2614 10201 22

MD Harford 24025 485 2049 793 680 5037 9043 23

DE Kent 10001 -271 4422 306 2200 2086 8744 24

NJ Cumberland 34011 185 2787 -154 2425 3189 8431 25

NJ Warren 34041 -4 2384 598 237 4274 7487 26

MD Cecil 24015 -121 1016 430 317 3262 4903 27

MD Queen Anne's 24035 -347 -163 320 102 2137 2048 28

MD Kent 24029 -25 140 107 182 1141 1546 29

** Bold font indicates those counties which are part of the Philadelphia CBSA

Table 4.16: Philadelphia CBSA+ 2002-2011 Percent Reductions and Rankings

State County FIPS NH3 NOX PM25 SO2 VOC SUM Rank

DE New Castle 10003 52% 47% 46% 95% 42% 69% 1

NJ Mercer 34021 75% 70% 8% 94% 41% 68% 2

NJ Hunterdon 34019 53% 46% 66% 46% 65% 57% 3

PA Northampton 42095 15% 42% 35% 66% 49% 57% 4

NJ Salem 34033 -8% 50% 42% 74% 55% 56% 5

NJ Burlington 34005 64% 53% 33% 85% 46% 52% 6

NJ Warren 34041 -1% 48% 53% 42% 59% 51% 7

NJ Somerset 34035 76% 40% 62% 62% 53% 50% 8

NJ Gloucester 34015 64% 43% 21% 81% 44% 50% 9

NJ Atlantic 34001 71% 40% 17% 52% 54% 48% 10

NJ Monmouth 34025 57% 40% 24% 60% 49% 46% 11

PA York 42133 10% 10% 33% 68% 30% 46% 12

NJ Middlesex 34023 74% 43% 16% 64% 46% 45% 13
50

State County FIPS NH3 NOX PM25 SO2 VOC SUM Rank

NJ Ocean 34029 72% 21% 41% 55% 52% 45% 14

NJ Cumberland 34011 29% 41% -17% 75% 39% 43% 15

NJ Camden 34007 80% 41% -21% 68% 44% 43% 16

PA Philadelphia 42101 26% 27% 9% 71% 51% 42% 17

PA Montgomery 42091 46% 33% 31% 51% 49% 42% 18

MD Harford 24025 49% 25% 46% 56% 49% 40% 19

PA Chester 42029 24% 34% 35% 60% 41% 39% 20

PA Berks 42011 11% 34% 16% 65% 34% 39% 21

MD Cecil 24015 -23% 22% 42% 49% 54% 38% 22

PA Delaware 42045 32% 24% -13% 59% 41% 37% 23

DE Kent 10001 -12% 44% 25% 54% 33% 37% 24

PA Lehigh 42077 25% 37% 26% 65% 30% 36% 25

PA Bucks 42017 42% 33% 32% 47% 33% 34% 26

PA Lancaster 42071 4% 29% 9% 55% 47% 30% 27

MD Kent 24029 -3% 12% 18% 47% 48% 30% 28

MD Queen Anne's 24035 -22% -6% 34% 19% 55% 21% 29

** Bold font indicates those counties which are part of the Philadelphia CBSA

4.4 Control Measure Analysis for PM2.5-Related Pollutants

Delaware’s 2011 NEI encompasses all emissions that could contribute to downwind areas. Delaware has 

used this inventory for a control measure analysis. The sections that follow present Delaware’s analyses 

of federal and Delaware control measures on a pollutant-by-pollutant basis, demonstrating that Delaware 

has controlled emission sources causing local ambient PM2.5 issues, and that may contribute to 

nonattainment and/or maintenance areas downwind. The analysis includes every source for each pollutant 

that is ≥ 25 tpy or ≥ 95% of all sources, and shows that all non-trivial sources are already controlled. 

Including New Castle in a nonattainment area under CAA 107(d)(1) would result in no additional

emission reductions in New Castle County. 

4.4.1 Sulfur Dioxide (SO2)

Because sulfates were determined to be the largest contributor to PM2.5 nonattainment in the northeast, 

Delaware adopted and implemented SIP provisions that cover all SO2 emitting sources and source 

categories and all such emissions in Delaware are now well controlled. 

In June 2013, Delaware submitted a technical support document to EPA, which presented a combination 

of ambient monitoring data analysis and conservative source-specific modeling to support a designation 

of attainment for the 2010 1-hour SO2 NAAQS for the entire state of Delaware. In summary, Delaware’s 

SO2 control efforts have focused primarily on requiring advanced SO2 emission controls on its largest 

point sources, and lowering the sulfur content of fuel used by all in-state sources, e.g.: 

• Recent amendments to 7 DE Admin. Code 1108 will reduce the sulfur limit for residual oil to 

0.5%, statewide, for all source sectors. 

• As of 12/31/2012, New Castle County’s two coal-fired EGUs, switched to natural gas, with one 

using residual oil. SO2 emission rates have been set at or below 0.26 lb/mmbtu since 2006 (7 DE 

Admin. Code 1146). 
51

• The allowable sulfur content of residual oil fired EGUs was reduced to an allowable level of 0.5% 

in 2006 (7 DE Admin. Code 1146).

• The carbon monoxide (CO) boilers at the Delaware City Refinery, historically the largest SO2

emitters in the state, were controlled with scrubbers in 2007/8 (Consent Decree). 

• Distillate oil has been regulated statewide at a level of 3000 ppm since 1971 (7 DE Admin. Code 

1108), and recent amendments to this regulation effective 07/2013 reduce the allowable limit to 15 

ppm. 

These controls, along with federal on-and-off-road fuel sulfur limits, have dramatically reduced New 

Castle’s SO2 emissions inventory. Delaware’s first SO2 SIP from 1970 indicates that statewide 1970 SO2

emissions were 232,000 tons per year, and in 2011 they have been reduced to 14,273 tons (a 94% 

reduction). This indicates that Delaware’s SO2 control strategy has been very effective. Appendix A, 

Table 1 discusses the emission sources and federal and Delaware controls that have been implemented for 

those sources. 

4.4.2 Oxides of Nitrogen (NOx)

Delaware has been nonattainment for the pollutant ozone since a standard was first established in 1971. 

Over the past 40 years Delaware has learned that transport is very significant relative to ozone, and that 

the only way to reduce ozone concentrations is to reduce the volatile organic compound (VOC) and 

nitrogen oxides (NOx) emissions that are causing them. As discussed above, VOC and NOx are also 

precursors to PM2.5. Over the last twenty years Delaware has adopted and implemented SIP provisions 

that cover all NOx emitting sources and source categories, and all such emissions in Delaware are now 

well controlled. 

Appendix A, Table 2 demonstrates 1) that the Delaware SIP contains measures that cover every nontrivial NOx emitting source and source category in the State. Thus, Delaware concludes that the 

Delaware emissions that would contribute to nonattainment and maintenance in downwind areas are those 

NOx emissions that are already reduced by the following adequate measures in Delaware’s SIP:

• Vehicle I/M requirements, which is one of the few cost effective means available to States to 

significantly reduce on-road mobile emissions (7 DE Admin. Code 1126 and 1136)

• RACT on all major NOx stationary sources, which establishes a baseline level of control and 

achieves large, cost effective reductions (7 DE Admin. Code 1112 and 1125).

• BACT on all coal and residual oil fired EGUs, and large industrial boilers, which ensure the 

largest emitters are well controlled (7 DE Admin. Code 1142 and 1146)

• BACT on all sources with high daily emissions, despite low annual emissions, which ensure all 

emissions on high PM2.5 days are controlled (7 DE Admin. Code 1144 and 1148.)

• Adoption of available regional measures to reduce emission from large non-point source 

categories (7 DE Admin. Code 1141, Sections 1, 2 and 4)

• Major and minor new source review, which ensures new units are well controlled (7 DE Admin. 

Code 1125)
52

4.4.3 Direct PM2.5

Delaware has been nonattainment for the pollutant PM2.5 since 2005 under the 1997 annual PM2.5

NAAQS, and since 2009 under the 2006 daily PM2.5 NAAQS. In November, 2012 EPA proposed a rule 

approving Delaware’s 2008 PM2.5 Attainment Demonstration and a 2012 revision to that SIP to address 

MOVES.25 Since then, Delaware’s monitors are showing attainment and Delaware has submitted a 

redesignation request and maintenance plan to EPA under the annual and daily PM2.5 NAAQS. Appendix 

A, Table 3 discusses the emission sources and federal and Delaware controls that have been implemented 

for those PM2.5 sources.

4.4.4 Volatile Organic Compounds (VOC)

Delaware has been nonattainment for the pollutant ozone since a standard was first established in 1971. 

Appendix A, Table 4 demonstrates that the Delaware SIP contains measures that cover every non-trivial 

VOC emitting source and source category in the State. Thus, Delaware concludes that the Delaware 

emissions that would contribute to nonattainment and maintenance in downwind areas are those VOC 

emissions that are already significantly controlled by the following measures in Delaware’s SIP:

• Vehicle I/M requirements, which is one of the few cost effective means available to States to 

significantly reduce on-road mobile emissions (7 DE Admin. Code 1126 and 1136)

• RACT on all major NOx and VOC stationary sources, which establishes a baseline level of control 

and achieves large, cost effective reductions (7 DE Admin. Code 1112 and 1125).

• BACT on all coal and residual oil fired EGUs, and large industrial boilers, which ensure the 

largest emitters are well controlled (7 DE Admin. Code 1142 and 1146)

• BACT on all sources with high daily emissions, despite low annual emissions, which ensure all 

emissions on high PM2.5 days are controlled (7 DE Admin. Code 1144 and 1148.)

• Adoption of available regional measures to reduce emission from large non-point source 

categories (7 DE Admin. Code 1141, Sections 1, 2 and 4)

• Adopting all federal Control Techniques Guidelines (CTGs) or issuance of a negative declaration

• Major and minor new source review, which ensures new units are well-controlled (7 DE Admin. 

Code 1125)

• VOC Control Measures on numerous area sources (7 DE Admin. Code 1124)

4.4.5 Ammonia (NH3)

Due to the lack of quality emission factors, effective control measures and relatively low emissions in 

New Castle County, Delaware has not focused on controlling ammonia emissions. Nonetheless, 2011 

emissions of ammonia have decreased 1,018 tpy from 2002 levels (1,940 vs. 922), or a 52 percent 

reduction. Appendix A, Table 5 discusses Delaware’s ammonia analysis. 

 25 The Homer vs. EPA ruling has held up final approval of this SIP but DNREC and EPA expect it to be approved. 
53

4.5 Summary of Emissions and Control Measure Analysis

The previous discussions in Section 4, as well as Appendix A demonstrate that:

1. the Delaware SIP contains measures that cover every non-trivial PM2.5-related pollutant emitting 

source and source category in the State, and 

2. that implementation of these measures has resulted in significant emission reductions in New 

Castle County (and Delaware has achieved more reductions than any other county since 2002) 

Thus, Delaware concludes based on this analysis of emissions and emissions related data that no part of 

Delaware should be designated as nonattainment due to the air quality in any nearby area. 

5 GEOGRAPHY/TOPOGRAPHY

Not applicable to Delaware and surrounding counties. The terrain is relatively flat.

6 JURISDICTIONAL BOUNDARIES 

All of New Castle County’s air quality management is under the jurisdictional authority of the State of 

Delaware. Air quality issues are handled by a single agency, the Delaware Department of Natural 

Resources and Environmental Control. 

Delaware does not participate as a member of Delaware Valley Regional Planning Commission, which 

serves PA and NJ mobile planning efforts. As such, there have been no coordinated planning efforts for 

mobile control measures between Delaware, NJ and PA for PM2.5. Mobile source controls are planned 

and implemented exclusively through DNREC, DELDOT and the Kent and Wilmington Area Planning 

Councils. In addition, since 2002 when Delaware was first designated nonattainment under the 1997 

annual NAAQS, no coordination of control measures occurred between Delaware and Pennsylvania for 

the other sources sectors (this included ozone control coordination as well). Furthermore, given that New 

Castle County ambient concentrations are well below the 2012 annual standard, DNREC does not foresee 

any multi-jurisdictional controls as a viable option. And finally, Delaware believes that 1) since the 

violations in PA appear to be highly influence by local emissions, and 2) the dominant boundary is the 

state lines and not the CBSA, then 3) it is impractical for Delaware to coordinate with PA on their local 

control measures, in order to bring PA violating monitors into attainment (e.g. Delaware has no influence 

on PA’s regulation determinations).

Designating New Castle County as a stand-alone attainment area, separate from the Philadelphia CBSA, 

will continue to simplify administrative and legal authorities relative to nonattainment requirements. 

Delaware will continue to actively interact with EPA and the regional planning organizations (OTC, 

MANEVU).
54

7 CONCLUSIONS

• All of Delaware’s monitors are recording PM2.5 concentrations that are significantly below the 

2012 NAAQS. In the Philadelphia CBSA, only Delaware and Chester Counties in Pennsylvania 

are monitoring concentrations that are above the 2012 NAAQS. 

• Ambient air quality analysis indicates that the nearby sites in Pennsylvania currently exceeding the 

annual average PM2.5 NAAQS are not representative of air quality in New Castle County, 

Delaware, and the air quality analysis supports not associating any part of Delaware with those 

two areas for the following reasons. 

o The New Garden site in Chester County data is typical of a site dominated by regional 

transport as shown by the seasonal and annual trends analysis. The change in monitoring 

method from the FRM to an FEM appears to have introduced a high bias into recent design 

values. Returning that site to the FRM appears to be returning data from that site to trends 

that are expected, and that follow the trends of other sites within the Philadelphia CBSA 

that are below the annual average NAAQS.

o The Chester site in Delaware County is significantly impacted by local sources as shown 

by ambient air quality trends and seasonal patterns, evaluation of high concentration days, 

speciation data analysis (SANDWICH and urban excess calculations), and emissions vs. 

distance. The Chester site is therefore not representative of the larger Philadelphia CBSA. 

Examination of the specific site characteristics also indicates high potential for nearby 

source impact. The Chester monitor is located within the fence line of a point source which 

manufactures sodium silicate and is also installed in an unpaved area. 

• Analysis of three years of meteorology indicates that while both Delaware’s MLK monitor and 

Pennsylvania’s Chester monitor are impacted by regional sources, the Chester monitor is impacted 

more by local sources when compared to the MLK monitor.

• In 2002, New Castle County’s total PM2.5- related pollutant emissions were ranked 1st in the 

CBSA. In 2011 New Castle ranked 5th in the CBSA – with approximately 5,000 tpy less than 

Delaware County’s total PM2.5-related emissions. 

• Although New Castle’s emissions are only two ranks below only two ranks below Delaware 

County, the closest DE monitor to the Chester monitor in Delaware County is Bellefonte (~8 mi.), 

with a 2010-2012 DV of only 9.8 μg/m3

. This is significantly less than the Chester DV (13.1 

μg/m3), leading Delaware to conclude local emissions play a major role in violations at the Chester 

monitor.

• Based on population vs. DVs over the years, Delaware believes population is not suitable as a tool 

in making boundary determinations for New Castle County because they are in fact inversely 

related. Since increased VMT and commuting are related to population, and Delaware statewide 

VMT does not correlate with air quality data, it also follows that these parameters should not be 

used in boundary designations. Also, relative to 2002 vehicle miles traveled (VMT), New Castle 

2010 VMT growth was negative 3%, the 18th lowest growth rate in the CBSA+ and ranked 8th in 

the CBSA.
55

• Total 2012 emissions of direct PM2.5 and its precursors from Delaware’s largest point sources 

decreased 87% between 2002 and 2012. This included a massive 99% reduction in SO2, followed 

by a 65% reduction in direct PM2.5, and NOx with a 52% decrease. VOC reductions of 54% have 

been taking place since the early 1990s due to Delaware’s ozone nonattainment issues over the 

years. Although NH3 has been reduced around 52%, this is still a significant reduction, since total 

New Castle County 2002 point source emissions were only 82 tons per year (tpy). 

• Based on 2002 emission inventories, New Castle ranked as the highest emitter in the Philadelphia 

CBSA of all PM2.5-related pollutants. However, due to the significant control measures Delaware 

has implemented since 2002, New Castle now ranks the highest in total emission reductions, 

both for the CBSA and CBSA+. 

• In terms of percent reductions between 2002 and 2011 in the CBSA, New Castle County is 

number one with a 69% overall reduction of PM2.5-related pollutants. The 2nd ranking County has 

a 52% overall reduction, and the two nonattaining counties Chester and Delaware have 39% and 

37% reductions, respectively. This demonstrates that Delaware emission sources are well 

controlled.

Based on this analysis Delaware concludes that the air quality in all of Delaware is below the 2012 

NAAQS, and that emissions from Delaware do not contribute to violations of the NAAQS in any nearby 

area, and that no part of Delaware, including New Castle County, should be designated as nonattainment

under CAA 107(d).
APPENDIX A 

CONTROL MEASURE ANALYSIS 

FOR PM2.5-RELATED POLLUTANTS 
2 

Table 1: SO2 Emission and Control Analysis –NCC 2011 NEI (≥ 25 TPY and ≥ 95%) 

Source Category 

2011 TPY % of 2011 NEI 

Description of Federal Control Measures and 

Measures in Delaware's SIP Potential Ad

Commercial Marine Vessels (primarily in-transit emissions from residual oil combustion)

972 40.8% Commercial Marine Vessels include ocean-going 

ships and other large craft. This category is subject to applicable federal measures such as the EPA C-3 Marine Engine Rule, and the Emission Control Areas established by the IMO, which require usage of ≤10,000 ppm sulfur residual fuel beginning in 2011, and ≤ 1,000 ppm beginning in 2017. 

Delaware has lito regulate off-r

Commercial/Industrial/Residential Combustion fired on Oil 

441 18.5% The commercial/institutional fuel combustion 

category includes small boilers, furnaces, heaters, and other heating units too small to be considered point sources. The commercial/institutional sector includes wholesale and retail businesses; health institutions; social and educational institutions; and federal, state, and local governments (i.e., prisons, office buildings) and are defined by SIC codes 50-99. The fuel types included in this source category are coal (SCC 2103002000), distillate oil (SCC 2103004000), residual oil (SCC 2103005000), natural gas (SCC 2103006000), and liquefied petroleum gas (LPG) (SCC 2103007000). Uses of distillate oil and kerosene include space and water heating. Emissions in this category are from many small units throughout the State. Recent amendments to 7 DE Admin. Code 1108 reduced the sulfur limit for residual oil to 0.5%, statewide, for all source sectors. Distillate oil has been regulated statewide at a level of 3,000 ppm since 1971 (7 DE Admin. Code 1108), and recent amendments to this regulation reduced the allowable limit to 15 ppm. 

This source catestringent allowaDE Admin. Codfeasible additioidentified. 
3 

Table 1: SO2 Emission and Control Analysis –NCC 2011 NEI (≥ 25 TPY and ≥ 95%) 

Source Category 

2011 TPY % of 2011 NEI 

Description of Federal Control Measures and 

Measures in Delaware's SIP Potential Ad

Delaware City Refinery (Premcor) 333 14.0% The main SO2 emission sources at the refinery are the 

Coker and Cracker CO boilers. Both of these units are well controlled with scrubbers that were installed under a federal consent decree. 2005 emissions from these two units were > 29,000 tpy, and 2012 emissions were less than 304 tpy. 

No strategies hareduce SO2 emi

DuPont Experimental Station 248 10.4% This facility has four (4) residual oil fired boilers and 

one (1) gas fired boiler, all rated at 96 mmBTU/hr each. All four oil fired boilers are currently permitted to use 

residual oil with a sulfur content not to exceed 0.5%. DuPont Experimental Station is currently paying for the installation of a natural gas line to the facility, after which all boilers will operate using natural gas. The goal is to have all boilers converted to natural gas by mid-2017. 

No strategies hareduce SO2 emi

Calpine - Edge Moor (Conectiv) 83 3.5% This facility is a power plant that consists of three 

gas/oil fired EGUs. (i.e., 86 MW, 174 MW, and 450 MW). All of Delaware EGUs 25 MW and greater are subject 

to 7 DE Admin. Code 1146, Electric Generating Unit (EGU) Multi-Pollutant Regulation. 1146 limits SO2

emissions from oil fired EGUs to a rate resulting from combusting 0.5% sulfur oil.Unit 3 fires gas as a primary fuel, with oil as a backup. Unit 3 has taken permit (permit AQM003/00007) conditions that include a restriction on the annual total hours of operation on residual fuel oil (no greater than 876 hrs/yr) and a restriction on total annual operating hours to not exceed 59% capacity 

No additional e

control measure
4 

Table 1: SO2 Emission and Control Analysis –NCC 2011 NEI (≥ 25 TPY and ≥ 95%) 

Source Category 

2011 TPY % of 2011 NEI 

Description of Federal Control Measures and 

Measures in Delaware's SIP Potential Ad

factor. The 0.5% sulfur in fuel limit of 7 DE Admin Code 1146 and these operating limits effectively cap the annual SO2 mass emissions levels below those 

included in 7 DE Admin Code 1146. Unit 4 fires gas as a primary fuel, with oil as a backup. Unit 4 has taken permit (permit AQM003/00007) conditions that include a restriction on the annual total hours of operation on residual fuel oil (no greater than 876 hrs/yr) and a restriction on total annual operating hours to not exceed 59% capacity factor. The 0.5% sulfur in fuel limit of 7 DE Admin Code 1146 and these operating limits effectively cap the annual SO2 mass emissions levels below those included in 7 DE Admin Code 1146. Unit 5, using residual fuel oil as primary fuel, is subject to the 0.5% sulfur in fuel limit of 7 DE Admin Code 1146, and the associated annual SO2 mass 

emissions cap. 

DuPont - Chestnut Run 67 2.8% SO2 emissions are from a 48 mmbtu/hr boiler and a 96 

mmbtu/hr boiler. Both boilers converted to gas in 2011, and are no longer allowed to fire oil. The firing of gas itself ensures these units are well controlled for SO2. 

No additional sfurther reduce S
5 

Table 1: SO2 Emission and Control Analysis –NCC 2011 NEI (≥ 25 TPY and ≥ 95%) 

Source Category 

2011 TPY % of 2011 NEI 

Description of Federal Control Measures and 

Measures in Delaware's SIP Potential Ad

On-Road Mobile 48 2.0% New vehicles must meet California vehicle emission 

standards (CA LEV 3) under 7 DE Admin. Code 1140. New and existing vehicles must be maintained under Delaware’s vehicle Inspection and Maintenance program, 7 DE Admin. Code 1126 and 1131. Extended idling of heavy duty vehicles is prohibited under 7 DE Admin Code 1145. EPA 2007 Heavy-Duty Highway Rule (40 CFR Part 86, Subpart P) limits the sulfur content in on-road diesel to 15ppm. 

No additional sfurther reduce S

category. 

DuPont - Red Lion 46 1.9% This facility is a Sulfuric Acid Plant. The emissions 

from this facility are primarily from the flare. The flare is the control device, and at this time no reasonable control measures to reduce flaredemissions have been identified. 

No additional sfurther reduce S

Evraz Claymont Steel 42 1.8% This facility ceased operations beginning December, 

2013. 

Not Applicable 

Total - categories covering all 2011 NEI sources that emit more than 25 TPY and ≥ 95% of SO2

2280 95.7% 

Total - all other 2011 NEI facilities and source categories not included above 

102 4.3% This SO2 quantity also includes many combustion 

turbines and diesel generators with very low TPY emissions. These units’ fuel sulfur limits are regulated under 7 DE Admin. Code 1108. 

Total 2011 Anthropogenic Emissions (TPY)

2,383 100% 
6 

Table 2: NOx Emission and Control Analysis – NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 TPY 

% of 

2011 NEI 

Description of Federal Control Measures and 

Measures in Delaware's SIP Potential Ad

On-Road Mobile 7,495 47.2% New vehicles must meet California vehicle emission 

standards (CA LEV 3) under 7 DE Admin. Code 1140. New and existing vehicles must be maintained under Delaware’s vehicle Inspection and Maintenance program, 7 DE Admin. Code 1126 and 1131. Extended idling of heavy duty vehicles is prohibited under 7 DE Admin Code 1145. Overall on-road mobile NOx emissions are capped in each of Delaware’s three counties by ozone SIP budgets, which are managed under 7 DE Admin. Code 1132, transportation conformity. 

Delaware has nfurther regulate Aside from I/M identified meastransportation cgenerally gain s(i.e., on the ordof tons per year$50,000 to over 

Commercial Marine Vessels 2,256 14.2% Commercial Marine Vessels include ocean-going 

ships and other large craft. This category is subject to applicable federal measures such as the EPA C-3 Marine Engine Rule, which specifically regulates NOx emissions from new engines. 

Delaware has lito regulate off-r

Non-Road equipment 1,659 10.5% These categories are subject to applicable federal 

measures only. 

Delaware has lito regulate off-rDelaware, as Commission (Ofeasibility of an Other potentiasuch as lawn-mgenerally gain (i.e., on the ordtons per year), 
7 

Table 2: NOx Emission and Control Analysis – NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 TPY 

% of 

2011 NEI 

Description of Federal Control Measures and 

Measures in Delaware's SIP Potential Ad

$50,000 to over 

Commercial/ Industrial/ Residential Combustion fired on Gas 

1,177 7.4% The commercial/institutional fuel combustion 

category includes small boilers, furnaces, heaters, and other heating units too small to be considered point sources. The commercial/institutional sector includes wholesale and retail businesses; health institutions; social and educational institutions; and federal, state, and local governments (i.e., prisons, office buildings) and are defined by SIC codes 50-99. The fuel types included in this source category are coal (SCC 2103002000), distillate oil (SCC 2103004000), residual oil (SCC 2103005000), natural gas (SCC 2103006000), and liquefied petroleum gas (LPG) (SCC 2103007000). Uses of natural gas and LPG in this sector include space heating, water heating, and cooking. Uses of distillate oil and kerosene include space and water heating. Emissions in this category are from many small units throughout the State, where facility-wide NOx emissions are generally less than 25 TPY (i.e., those not covered in the point source inventory). 7 DE Admin Code 1112 requires the control of NOx

emissions from fuel burning equipment. Under 1112, units with maximum rated heat input capacities equal to or larger than 50 MMBtu/hr must be controlled by installation of either low excess air and low NOx

burner technology or flue gas recirculation technology. Units between 15 and 50 MMBtu/hr must receive an annual tune up performed by qualified personnel to minimize NOx emissions. Most commercial/institutional combustion units are subject to the annual tune-up requirements, or are less than 15MMBtu/hr and are exempt from the requirements of 1112. 

Additional contare possible. 7 be revised to acreductions:  1112 could 

applicable with the pothresholds; 1112 could to 5MMBTpredominatannual tuneabout 5% f

 1112 could 

the 25 MMrange to inlow NOx bu

recirculatioreduce NOunit

Other measures similar reductioGiven the high number of very this category is of equipment (NAdmin. Code 1source that emit
8 

Table 2: NOx Emission and Control Analysis – NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 TPY 

% of 

2011 NEI 

Description of Federal Control Measures and 

Measures in Delaware's SIP Potential Ad

Delaware City Refinery 1,072 6.8% The Delaware City Refinery is a petroleum refinery. 

NOx emissions are controlled under 7 DE Admin Code 1112 (NOx RACT), and also under a NOx cap/PAL established pursuant to Section 2.0 of 7 DE Admin Code 1142 and 1125. The NOx cap began in 2011 at 2,525 TPY (i.e., actual 2008 emission levels), and decreases to 1,650 TPY beginning 2015. Delaware’s March 15, 2011 SIP revision, “Demonstration that Amendments to Section 2.0 of 7 DE Admin Code 1142, Control of NOx Emissions from 

Industrial Boilers and Process Heaters at Petroleum Refineries Do not Interfere with Any Applicable 

Requirement of the Clean Air Act” provides a detailed discussion of the facility-wide NOx cap. The following information demonstrates the stringency of the facility-wide NOx cap:  Thirteen of the refinery’s industrial boilers were 

subject to the EPA NOx SIP Call, which was implemented in Delaware under 7 DE Admin Code 1139. 

 The initial 2,525 TPY NOx cap is significantly 

less than the annualized NOx SIP Call cap1, 3,333 

TPY, which indicates that implementation of RACT and NSR at the refinery have resulted in the implementation of NOx controls at the refinery. 

 The 1,650 TPY NOx cap represents a 35% 

Delaware concllower the NOx additional contridentified that wlevels below the 

1 The referenced SIP revision includes a demonstration that the refinery emissions are uniform across the year, and regulation on a TPY basi

basis is acceptable. Based on this the 1139 budgets were annualized by multiplying by 12/5. 
9 

Table 2: NOx Emission and Control Analysis – NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 TPY 

% of 

2011 NEI 

Description of Federal Control Measures and 

Measures in Delaware's SIP Potential Ad

reduction beyond RACT limits (i.e., actual 2008 levels), and more than an additional 50% reduction below NOx SIP Call levels. In addition, all future growth at the refinery must occur under this NOx cap. 

Calpine - Hay Road (Conectiv) 602 3.8% This facility is a power plant that consists of six 

combined cycle gas-fired (oil backup) EGUs. Units 1-3 are subject to 7 DE Admin Code 1112 (NOx RACT) limits of 25 to 88 ppm, 1-hour average, depending on fuel and firing mode. Units 5-7 are subject to 7 DE Admin. Code 1112, plus they are 

controlled by SCR as required by 7 DE Admin. Code 1125 (NOx LAER plus offsets). 

SCR is the mosavailable NOx ecommercially aand combined csuch as those inHay Road units SCR. It is technically Hay Road units presently incorpyear life and usit is estimated threducing NOx fcollectively is aincremental ton reduce NOx ma72% (or 433 T

Calpine - Edge Moor (Conectiv) 346 2.2% This facility is a power plant that consists of three 

gas/oil fired EGUs. (i.e., 86 MW, 174 MW, and 450 MW). NOx emissions are regulated under 7 DE Admin Code 1112, NOx RACT, and 7 DE Admin Code 1146 Electric Generating Unit (EGU) Multi-Pollutant Regulation. All units complied with 1112 through the installation of low NOx burners. 1146 imposes both a unit specific annual NOx cap, and a 0.125 lb/MMBTU emission limitation, demonstrated on a 

SCR is the mosavailable NOx efor a gas/oil fireas these at the CAdditional contexisting low Ntechnology with the following tw
10 

Table 2: NOx Emission and Control Analysis – NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 TPY 

% of 

2011 NEI 

Description of Federal Control Measures and 

Measures in Delaware's SIP Potential Ad

rolling 24-hour average basis. Unit 3 fires gas as a primary fuel, with oil as a backup. Unit 3 NOx emissions are controlled by: low-NOx burners, overfire air, and SNCR. Unit 3 has taken permit (permit AQM-003/00007) conditions that include a restriction on the annual total hours of operation on residual fuel oil (no greater than 876 hrs/yr) and a restriction on total annual operating hours to not exceed 59% capacity factor. The use of gas as a primary fuel, and the 0.125 lb/MMBTU limit of 7 DE Admin Code 1146 and these operating limits effectively cap the annual NOx mass emissions levels below those included in 7 DE Admin Code 1146. Unit 4 fires gas as a primary fuel, with oil as a backup. Unit 4 has taken permit (permit AQM003/00007) conditions that include a restriction on the annual total hours of operation on residual fuel oil (no greater than 876 hrs/yr) and a restriction on total annual operating hours to not exceed 59% capacity factor. The use of gas as a primary fuel, and the 0.125 lb/MMBTU limit of 7 DE Admin Code 1146 and these operating limits effectively cap the annual NOx mass emissions levels below those included in 7 DE Admin Code 1146. Unit 5’s primary fuel is residual fuel oil, and incorporates low-NOx burners, overfire air, and SNCR for NOx emissions rate reduction. Unit 5 is subject to the 0.125 lb/MMBTU limit of 7 DE Admin Code 1146 and the associated annual NOx mass cap in 7 DE Admin Code 1146. 

 Unit 3: Th

reducing ththe unit’s 2(assuming annual heat lb/MMBTU basement) of NOx redemissions bactual 2011 

 Unit 4: Th

reducing ththe unit’s 2(assuming annual heat lb/MMBTU basement) of NOx redemissions bactual 2011 
11 

Table 2: NOx Emission and Control Analysis – NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 TPY 

% of 

2011 NEI 

Description of Federal Control Measures and 

Measures in Delaware's SIP Potential Ad

Locomotives 272 1.7% These categories are subject to applicable federal 

measures only. 

Delaware has lito regulate off-r

DuPont Experimental Station 180 1.1% This facility has four (4) residual oil fired boilers and 

one gas fired boiler, each rated at 96 mmBTU/hr each. Each boiler is equipped with low NOx burner and low excess air technology under 7 DE Admin Code 1112 (NOx RACT). DuPont Experimental Station is currently paying for the installation of a natural gas line to the facility, after which all boilers will operate using natural gas. The goal is to have all boilers converted to natural gas by mid-2017. 

SNCR and SCR combustion NOapplicable to gacosts would be boilers. 

Commercial/ Industrial/ Residential Combustion fired on Oil 

175 1.1% The commercial/institutional fuel combustion 

category includes small boilers, furnaces, heaters, and 

other heating units too small to be considered point sources. The commercial/institutional sector includes wholesale and retail businesses; health institutions; social and educational institutions; and federal, state, and local governments (i.e., prisons, office buildings) and are defined by SIC codes 50-99. The fuel types included in this source category are coal (SCC 2103002000), distillate oil (SCC 2103004000), residual oil (SCC 2103005000), natural gas (SCC 2103006000), and liquefied petroleum gas (LPG) (SCC 2103007000). Uses of natural gas and LPG in this sector include space heating, water heating, and cooking. Uses of distillate oil and kerosene include space and water heating. Emissions in this category are from many small units 

Additional contare possible. 7 be revised to acreductions:  1112 could 

applicable with the pothresholds; 1112 could to 5MMBTpredominatannual tuneabout 5% f

 1112 could 

the 25 MMrange to inNOx burner 
12 

Table 2: NOx Emission and Control Analysis – NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 TPY 

% of 

2011 NEI 

Description of Federal Control Measures and 

Measures in Delaware's SIP Potential Ad

throughout the State, where facility-wide NOx emissions are generally less than 25 TPY (i.e., those not covered in the point source inventory). Most commercial/institutional combustion units are subject to the annual tune-up requirements, or are less than 15MMBtu/hr and are exempt from the requirements of 1112. 

recirculatioreduce NOunit. Other identified aeffectivene

Given the high number of very this category is of equipment (NAdmin. Code 1source that emit

Evraz Claymont Steel 166 1.0% This facility ceased operations beginning December, 

2013. 

Not Applicable 

Residential Wood Combustion 60 0.4% This category is regulated under 40 C.F.R. Part 60 

Subpart AAA New Source Performance Standards (“NSPS”) 

No economicallcontrol strategiebeen identified. 

Sunoco 54 0.3% This facility was subject to 7 DE Admin. Code 1112 

(NOx RACT). It was subject to beyond-RACT NOx control under Section 1 of 7 DE Admin. Code 1142. 

The facility is n

DuPont - Chestnut Run 48 0.3% 48 mmbtu/hr boiler subject to annual tune-up to 

minimize NOx emission under 7 DE Admin Code 1112 (NOx RACT). 96 mmbtu/hr boiler equipped with low NOx burner and low excess air technology under 7 DE Admin Code 1112 (NOx RACT). All boilers at this facility converted to gas in 2011, and are no longer allowed to fire oil. 

SNCR and SCR combustion NOapplicable to oicosts would be fired boilers. 
13 

Table 2: NOx Emission and Control Analysis – NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 TPY 

% of 

2011 NEI 

Description of Federal Control Measures and 

Measures in Delaware's SIP Potential Ad

Formosa Plastics 32 0.2% This facility produces vinyl chloride monomer. 

NOx emissions are from a 30 and a 40 mmBTU/hr boiler, subject to annual tune-up requirements to minimize NOx emissions under 7 DE Admin Code 1112 (NOx RACT). 

SNCR and SCR combustion NOapplicable to oi The estima

retrofit of Sfrom $5,54reduction tof NOx redreduction o

 The estima

retrofit of Sfrom $12,1reduction tof NOx redreduction o

Given that these and that emissiobe low in the fuRACT is not wa

FMC 31 0.2% NOx emissions from two 25 mmBTU/hr boilers and 

three small spray dryers. Annual tune-ups to minimize NOx emissions on all NOx emitting units is required by 7 DE Admin. Code 1112 (NOx RACT). 

No control meafrom this facilitGiven that these and that emissiobe low in the fuRACT is not wa
14 

Table 2: NOx Emission and Control Analysis – NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 TPY 

% of 

2011 NEI 

Description of Federal Control Measures and 

Measures in Delaware's SIP Potential Ad

DuPont - Edge Moor 27 0.2% NOx emissions are from small (<50 mmBTU/hr) 

combustion units, which are subject to annual tune-up requirements to minimize NOx under 7 DE Admin 

Code 1112 (NOx RACT). 

No control meafrom this facilitGiven that these and that emissiobe low in the fuRACT is not wa

Total - categories covering all 

2011 NEI sources that emit more 

than 25 TPY and ≥ 95% of NOx. 

15,654 98.7% 

Total - all other 2011 NEI facilities 

and source categories not included 

above.

212 1.3% Many of these small sources are also controlled under 

the measures in Delaware's SIP. This includes small sources covered by 7 DE Admin. Code 1112, 1144 and 1148. 

Total 2011 Anthropogenic Emissions (TPY) 

15,866 100 
15 

Table 3: PM2.5 Emission and Control Analysis – NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 TPY 

% of 

2011 NEI 

Description of Federal Control Measures and 

Control Measures in Delaware's SIP Potential Add

Residential Wood Combustion 521 20.8% This category is regulated under 40 C.F.R. Part 60 

Subpart AAA New Source Performance Standards (“NSPS”) and 7 DE Admin. Code 1114 and 7 DE Admin. Code 1114, Visible Emissions. 

The NSPS covers npotential additionawood stove changestudy done by New 

their change-out prton of PM2.5 reduce

reductions of PM2.5

Paved Road Dust 408 16.3% This is an on-road category and no reasonable 

measures have been identified to reduce these 

emissions. Delaware does not regulate this category in its SIP. Note: these emissions do not take into account the transport fraction. 

None 

Delaware City Refinery (Premcor) 

281 11.2% The main PM2.5 emission sources at the refinery 

are the Coker and Catalytic Cracker CO boilers. Both of these units are well controlled with scrubbers that were installed under a federal consent decree. 2002 emissions from these two units were 1,241 tpy and total 2012 PM2.5 from the 

entire refinery was 312 TPY. 

No economically femeasures have beePM2.5 emissions fro

On-road Mobile 241 9.6% New vehicles must meet California vehicle emission

standards (CA LEV 3) under 7 DE Admin. Code 1140. New and existing vehicles must be maintained under Delaware’s vehicle Inspection and Maintenance program, 7 DE Admin. Code 1126 and 1131. Extended idling of heavy duty vehicles is prohibited under 7 DE Admin Code 1145. 

Delaware has no aufurther regulate tailAside from I/M proidentified measures transportation contgenerally gain smaon the order of tonper year), and that over $1 million. 

2 Keene Woodstove Changeout Campaign 2009-2010, Final Report. New Hampshire Department of Environmental Services, September 201
16 

Table 3: PM2.5 Emission and Control Analysis – NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 TPY 

% of 

2011 NEI 

Description of Federal Control Measures and 

Control Measures in Delaware's SIP Potential Add

Overall on-road mobile emissions are capped in New Castle County by PM2.5 SIP budgets, which 

are managed under 7 DE Admin. Code 1132, transportation conformity. 

Construction Dust (road, residential and commercial) 

174 6.9% Delaware Admin Code 1106 - Particulate 

Emissions from Construction and Materials Handling (effective 2/01/1981, administratively revised 9/01/2008). In summary, regulation 1106 states that any persons doing demolition, land clearing, land grading (including grading for roads), excavation, material transport, or the use of non-paved roads on private property are required to employ control dust control measures, when the Department determines that such activities could emit dust in quantities sufficient to cause air pollution. 

EPA’s Menu of Opcontrol plan includwater treatment of sites.” However, iPM10” and DNREcontrol measures fotransport fraction n

Non-Road Equipment 161 6.4% These categories are subject to applicable federal 

measures only. 

Delaware has limitregulate off-road mDelaware, as paCommission (OTCfeasibility of an offOther potential melawn-mower tradegain small incremorder of tenths of a 

Commercial Marine Vessels (primarily in-transit emissions from residual oil combustion) 

138 5.5% Commercial Marine Vessels include ocean-going 

ships and other large craft. This category is subject to applicable federal measures only, such 

as the EPA C-3 Marine Engine Rule. 

Delaware has limitregulate off-road m

Commercial Cooking 135 5.4% 7 DE Admin. Code 1114, Visible Emissions, 

applies to this source category. 

Additional control of Options lists onlcontrollable. Chain 
17 

Table 3: PM2.5 Emission and Control Analysis – NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 TPY 

% of 

2011 NEI 

Description of Federal Control Measures and 

Control Measures in Delaware's SIP Potential Add

estimated at 1.8 tpy 

emissions inventoroverall emissions treductions are sma

Calpine - Hay Road (Conectiv) 106 4.2% The Hay Road EGUs are fired on natural gas and 

distillate oil. Much of the PM2.5 emissions are 

condensable. Direct PM2.5emissions are limited to 0.3 lb/mmbtu 

under 7 DE Admin. Code 1104, Particulate Emissions From Fuel Burning Equipment. 

No economically fetechnology to redu

this facility has beeCode 1108 and 111

and NOx, and ensucontrolled relative 

concentrations. 

Evraz Claymont Steel 63 2.5% This facility ceased operations beginning 

December, 2013. 

Not Applicable 

Crop Production 47 1.9% Delaware farmers employ crop rotation and no-till 

practices. [Note that transport fraction not yet applied] 

No additional contr

due to farming hav

Formosa Plastics 33 1.3% This facility produces vinyl chloride monomer. 

Emissions almost exclusively from polymer drying (presumable from VOC condensation). PM2.5 is 

controlled by baghouses. 

No additional direc

been identified for 

Sunoco 30 1.2% Not applicable – this facility is now closed. Not Applicable Commercial/ Industrial/ Residential Combustion fired on Oil

21 0.8% The commercial/institutional fuel combustion 

category includes small boilers, furnaces, heaters, 

and other heating units too small to be considered point sources. The commercial/institutional sector includes wholesale and retail businesses; health institutions; social and educational institutions; and federal, state, and local governments (i.e., prisons, office buildings) and are defined by SIC codes 50-99. The fuel types included in this source category are coal (SCC 2103002000), distillate oil (SCC 2103004000), residual oil (SCC 2103005000), natural gas (SCC 2103006000), and liquefied petroleum gas (LPG) (SCC 2103007000). Uses of natural gas and LPG in this 

No economically fetechnology to redu

this source categorAdmin. Code 1108 precursors SO2 and 

category is well coambient PM2.5 conc
18 

Table 3: PM2.5 Emission and Control Analysis – NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 TPY 

% of 

2011 NEI 

Description of Federal Control Measures and 

Control Measures in Delaware's SIP Potential Add

sector include space heating, water heating, and cooking. Uses of distillate oil and kerosene include space and water heating. Emissions in this category are from many small units throughout the State,. Direct PM2.5 emissions are limited to 0.3 lb/mmbtu under 7 DE Admin. Code 1104, Particulate Emissions From Fuel Burning Equipment. 

FMC Biopolymer 19 0.8% Emissions are primarily from the “Air Dryers”. 

Control device for PM is scrubbers. 

No economically fetechnology to redu

this facility has bee

DuPont Experimental Station 19 0.7% This facility has four (4) residual oil fired boilers 

and one gas fired boiler, each rated at 96 mmBTU/hr each. Direct PM2.5 emissions are limited to 0.3 lb/mmbtu 

under 7 DE Admin. Code 1104, Particulate Emissions From Fuel Burning Equipment. DuPont Experimental Station is currently paying for the installation of a natural gas line to the facility, after which all boilers will operate using natural gas. The goal is to have all boilers converted to natural gas by mid-2017. 

No economically fetechnology to redu

these units has been SO2 and NOx are w

these units are well impact on ambient 

Total - categories covering all 2011 NEI sources that emit more than 25 TPY and ≥ 95% of PM2.5 

2,396 95.6% 

Total - all other 2011 NEI facilities and source categories not included above 

112 4.4% 
19 

Table 3: PM2.5 Emission and Control Analysis – NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 TPY 

% of 

2011 NEI 

Description of Federal Control Measures and 

Control Measures in Delaware's SIP Potential Add

Total 2011 Anthropogenic Emissions (TPY) 

2,507 100% 
20 

Table 4: VOC Emission and Control Analysis - NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 

TPY % of 2011 Inventory

Description of Federal Control Measures and 

Control Measures in Delaware's SIP Potential Add

On-Road Mobile 3,285 28.6% New vehicles must meet California vehicle 

emission standards (CA LEV 3) under 7 DE Admin. Code 1140. New and existing vehicles must be maintained under Delaware’s vehicle Inspection and Maintenance program, 7 DE Admin. Code 1126 and 1131. Extended idling of heavy duty vehicles is prohibited under 7 DE Admin Code 1145. Overall on-road mobile emissions are capped in each of Delaware’s three counties by ozone SIP budgets, which are managed under 7 DE Admin. Code 1132, transportation conformity. 

Delaware has no afurther regulate taAside from I/M pridentified measuretransportation congenerally gain smon the order of tonper year), and that over $1 million. 

Non-Road equipment 2,094 18.3% These categories are subject to applicable federal 

measures only. Delaware has limi

regulate off-road mDelaware, as pCommission (OTfeasibility of an ofOther potential mas lawn-mower generally gain smon the order of teyear), and that hover $1 million. 

Commercial/Consumer Products 1,245 10.9% Commercial and consumer products are defined 

as non-industrial products used around the home, 

Delaware’s SIP custringent provision
21 

Table 4: VOC Emission and Control Analysis - NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 

TPY % of 2011 Inventory

Description of Federal Control Measures and 

Control Measures in Delaware's SIP Potential Add

office, institution, or similar settings. Included are hundreds of individual products, including personal care products (SCC 2460100000), household products (SCC 2460200000), automotive aftermarket products (SCC 2460400000), coatings and related products (SCC 2460500000), adhesives and sealants (SCC 2460600000), Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) related products (SCC 2460800000), and other miscellaneous products (SCC 2460900000). The VOCs in these products may act either as the carriers for the active product ingredients or as the active ingredients themselves. This category has undergone three rounds of regulation in Delaware. First under a 1998 National Rule (63 FR 48819), then under a more stringent 2002 Delaware regulation (Section 2.0 of 7 DE Admin. Code 1141) which was based on an OTC model rule. Finally, under an update to Section 2.0 of 7 DE Admin. Code 1141 which was based on a 2006 revised OTC model rule, and which had a 2009 compliance date. 

those of the most by any state). 3

Delaware does noregulate manufactof the State of Delonly means availaemission in this caallowable VOC coDelaware. Delaware representhese manufactureto further reduce aown would result in Delaware, ratheof reformulation tIn other words, Denot large enough fexpense of reformfrom a national or for Delaware to re

Residential Wood Combustion 633 5.5% Delaware does not regulate this category in its 

SIP. Woodstoves are regulated under 40 C.F.R. Part 60 Subpart AAA New Source Performance Standards (“NSPS”). 

No economically strategies for this identified. 

Architectural and Industrial Maintenance (AIM) Coatings 

619 5.4% Architectural surface coating operations consist 

of applying a thin layer of coating such as paint, 

Delaware’s SIP custringent provision

3 The OTC commissioners approved an updated consumer products model rule in May 2012. Delaware plans to propose an update to its reg

rule in the future 

4 Note that the OTR states are currently considering an update to their model rule. This is based on CARB 2006 amendments, plus potential 

paint thinner and multi-purpose solvents, and has the potential to reduce Delaware VOC emissions by 365 TPY. 
22 

Table 4: VOC Emission and Control Analysis - NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 

TPY % of 2011 Inventory

Description of Federal Control Measures and 

Control Measures in Delaware's SIP Potential Add

(Area Source Category) paint primer, varnish, or lacquer to architectural 

surfaces, and the use of solvents as thinners and for cleanup. Surface coatings include either a water-based or solvent-based liquid carrier that generally evaporates in the curing process. Architectural surface coatings are applied to protect the substrate and/or to increase the aesthetic value of a structure. Industrial maintenance coatings include primers, sealers, undercoats, and intermediate and topcoats formulated for and applied to substrates in industrial, commercial, coastal, or institutional situations that are exposed to extreme environmental and physical conditions. These conditions include immersion in water, chemical solutions and corrosives, and exposures to high temperatures. AIM coatings are regulated under Section 1 of 7 DE Admin. Code 1141. This regulation is based on an Ozone Transport Commission (OTC) model rule (which was based on California regulations), and which is much more stringent than the current federal rule. The compliance date of this regulation was 1/1/2005. 

those of the most by any state)5. Delaware does noregulate manufactof the State of Delonly means availaemission in this caallowable VOC coDelaware. Delaware representhese manufactureto further reduce aown would result in Delaware, ratheof reformulation tIn other words, Denot large enough fexpense of reformfrom a national or for Delaware to re

Graphic Arts (Area Source Category) 

507 4.4% Printing operations are a source of VOC 

emissions due to the volatile organic content of inks and thinners used in the industry. It is estimated that, on average, half of the graphic arts establishments are in-house printing services in non-printing industries. The remaining establishments are located at businesses whose 

Delaware’s SIP custringent identifiepoint (i.e., those o

5 An update AIM model rule was approved by the OTC on June 3, 2010, which has not yet been adopted by any state. Delaware plans to pro

regulations based on this model rule in the future. 
23 

Table 4: VOC Emission and Control Analysis - NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 

TPY % of 2011 Inventory

Description of Federal Control Measures and 

Control Measures in Delaware's SIP Potential Add

main function is printing or graphic arts. Large printing operations with VOC emissions of 10 TPY or more are included in the point source inventory. All sources with maximum theoretical emissions equal to or greater than 7.7 TPY are subject to the CTG based requirements in Section 37 of 7 DE Admin Code 1124 (VOC RACT). Offset lithographic and letterpress emission sources with maximum theoretical emissions equal to or greater than 15 pounds per day are subject to the CTG based requirements in Section 47 of 7 DE Admin Code 1124 (VOC RACT). 

Retail Gasoline Marketing –  Stage I Vapor Recovery  Stage II Vapor Recovery 

 Tank Breathing  Trucks in Transit

442 3.9% Stage I emissions (i.e., tank truck refilling of 

storage tanks) are controlled by vapor balancing under Section 26 of 7 DE Admin. Code 1124 (VOC RACT). Stage II emissions (i.e., refueling of vehicles) are controlled by vapor balancing under Section 36 of 7 DE Admin. Code 1124 (VOC RACT). Gasoline tank breathing emissions are subject to annual leak testing and permitting requirements under Section 36 of 7 DE Admin. Code 1124 (VOC RACT) Gasoline tank truck emissions are subject to annual leak testing and permitting requirements under Section 27 of 7 DE Admin. Code 1124 (VOC RACT). 

No control measufrom Tank Breathbeen identified. Additional reductirevising Stage I anCalifornia EVR reDelaware has begStage I and Stage could yield VOC 

Auto body Refinishing 404 3.5% Auto refinishing is the repairing of worn or 

damaged automobiles, light trucks, and other vehicles, and refers to any coating applications that occur subsequent to those at original 

Delaware’s SIP retechnology for thi
24 

Table 4: VOC Emission and Control Analysis - NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 

TPY % of 2011 Inventory

Description of Federal Control Measures and 

Control Measures in Delaware's SIP Potential Add

equipment manufacturer (OEM) assembly plants (i.e., coating of new cars is not included in this category). The majority of these operations occur at small body shops that repair and refinish automobiles. This category covers solvent emissions from the refinishing of automobiles, including paint solvents, thinning solvents, and solvents used for surface preparation and cleanup. Autobody refinishing is regulated under Section 11 of 7 DE Admin Code 1124. This source category has undergone three rounds of regulation in Delaware since 1990 (i.e., 1st CTG RACT, then OTC Model Rule 1 in 2002, and now OTC Model Rule 2 which had a compliance date of 1/1/2012). 

Gasoline Marketing - Portable Fuel Containers 

374 3.3% Portable fuel containers are regulated nationally 

by the EPA under 40 CFR Part 59, Subpart F. 

No control measufrom this category 

Industrial Adhesives (Area Source Category) 

294 2.6% Regulated under Section 4.0 of 7 DE Admin. 

Code 1141. 1141 is much more stringent than the most recent EPA CTG, and has broader coverage than the CTG (i.e., it covers field applied roofing adhesives and sealants not covered by the CTG). These requirements took effect on 5/1/2009. 

Delaware’s SIP rtechnology for thiAdditional regulatfeasible at this tim

Degreasing (Area Source Category) 

191 1.7% Solvent cleaning is the process of using organic 

solvents to remove grease, fats, oils, wax or soil from various metal, glass, or plastic items. Nonaqueous solvents such as petroleum distillates, chlorinated hydrocarbons, ketones, and alcohols have been used historically; however, the use of aqueous cleaning systems for some applications has recently gained acceptance. The types of equipment used in this method are categorized as cold cleaners, open top vapor degreasers, or conveyorized degreasers. 

This category has regulation in DelaOTC Model Rule regulated much mthe CTG. DNREC has starteAdmin Code 1124Cleaning and Dryreduce VOC emis
25 

Table 4: VOC Emission and Control Analysis - NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 

TPY % of 2011 Inventory

Description of Federal Control Measures and 

Control Measures in Delaware's SIP Potential Add

Degreasing is regulated under Section 33 of 7 DE Admin. Code 1124. 

Gasoline Marketing – Commercial Marine Vessel Evaporation Losses 

142 1.2% Not regulated beyond any applicable federal 

measures. 

No control measucategory have bee

Delaware City Refinery 139 1.2% The Delaware City Refinery is a petroleum 

refinery. VOC emissions are subject to 7 DE Admin Code 

1124 (VOC RACT). In addition, numerous sources at the facility are subject to emission limits established under 7 DE Admin. Code 1125 (LAER plus offsets). 

The OTC finalized address VOC emiVOC storage tankDelaware and othsigned a MOU, wOTC members to revise existing rulJanuary 2014 or aDelaware is pursu

Industrial Surface Coatings (Area Source Category) 

139 1.2% This source category is covered under Section 1 

of 7 DE Admin. Code 1141 and several sections of 7 DE Admin. Code 1124, based on CTGs. 

Delaware’s SIP rtechnology for thiAdditional regulafeasible at this tim

Land application of Agriculture Herbicides & Pesticides 

114 1.0% None. Regulation of this 

State of DelawareThe only identifiethis source categoof the herbicide or command sufficiefeasible. This cateEPA under a natio
26 

Table 4: VOC Emission and Control Analysis - NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 

TPY % of 2011 Inventory

Description of Federal Control Measures and 

Control Measures in Delaware's SIP Potential Add

DuPont - Edge Moor 99 0.9% VOC emissions are subject to an 81% reduction 

under Section 50 of 7 DE Admin Code 1124 (VOC RACT). 

No control measufrom this facility h

Commercial Marine Vessels 71 0.6% Commercial Marine Vessels include ocean-going 

ships and other large craft. This category is subject to the federal EPA C-3 Marine Engine Rule, which established standards for emissions of hydrocarbons from new Category 3 engines. 

Delaware has limiregulate off-road m

Evraz Claymont Steel 69 0.6% This facility ceased operations beginning 

December, 2013. 

Not Applicable 

Formosa Plastics 59 0.5% This facility produces vinyl chloride monomer. 

This facility is subject to 7 DE Admin. Code 1112 and 1124 (VOC RACT). 

No additional feasidentified to reducfacility. 

Commercial/Industrial/ Residential Combustion fired on Gas

56 0.5% The commercial/institutional fuel combustion 

category includes small boilers, furnaces, heaters, and other heating units too small to be considered point sources. The commercial/institutional sector includes wholesale and retail businesses; health institutions; social and educational institutions; and federal, state, and local governments (i.e., prisons, office buildings) and are defined by SIC codes 50-99. The fuel types included in this source category are coal (SCC 2103002000), distillate oil (SCC 2103004000), residual oil (SCC 2103005000), natural gas (SCC 2103006000), and liquefied petroleum gas (LPG) (SCC 2103007000). Uses of natural gas and LPG in this sector include space heating, water heating, and cooking. Uses of distillate oil and kerosene include space and water heating. 

No economically technology to redusource category hAdmin. Code 110precursors SO2 an

category is well coon ambient PM2.5 
27 

Table 4: VOC Emission and Control Analysis - NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 

TPY % of 2011 Inventory

Description of Federal Control Measures and 

Control Measures in Delaware's SIP Potential Add

Emissions in this category are from many small units throughout the State, where facility-wide VOC emissions are generally less than 5 TPY (i.e., those not covered in the point source inventory). VOC emissions from this source category are not regulated. 

Prescribed Fires 52 0.5% Open burning is restricted under 7 DE Admin. 

Code 1113. 

No economically measures to reducsource category h

Sunoco 46 0.4% This facility was subject to 7 DE Admin. Code 

1112 and 1124 (VOC RACT). 

The facility is now 

Printpack 44 0.4% The emissions from the facility are from seven 

flexographic printing presses, a photopolymer plate making system, and automatic parts washer, and a waste solvent tank. Emissions are controlled by a regenerative thermal oxidizer operated pursuant to 7 DE Admin. Code 1124 (VOC RACT). 

No economically further reduce VOhave been identifi

Magellan Terminals 39 0.3% Magellan Terminals is a liquid fuels marketing 

and bulk fuels terminal and subject to 7 DE Admin. Code 1124 (VOC RACT), Sections , 30, 31, and 49. Magellan, to avoid Nonattainment New Source Review, plans to keep their net emission increase per unit below the significant emission rate of 25 TPY. 

The OTC finalized address VOC emiVOC storage tankDelaware and othsigned a MOU, wOTC members to revise existing rulJanuary 2014 or aDelaware is pursu
28 

Table 4: VOC Emission and Control Analysis - NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 

2011 

TPY % of 2011 Inventory

Description of Federal Control Measures and 

Control Measures in Delaware's SIP Potential Add

Traffic Markings (Area Source Category) 

37 0.3% The VOC of traffic marking coatings is limited to 

150 grams of VOC per liter of coating under Section 1 of 7 DE Admin. Code 1141, Architectural and Industrial Maintenance Coatings. 

No feasible additibeen identified to this source catego

Calpine - Hay Road (Conectiv) 33 0.3% This facility is a power plant that consists of six 

combined cycle gas fired (oil backup) EGUs. 

No feasible additibeen identified to gas-and oil-fired E

Calpine - Edge Moor (Conectiv) 25 0.2% This facility is a power plant that consists of 

three gas/oil fired EGUs. (i.e., 86 MW, 174 MW, and 450 MW). Calpine’s permit establishes a facility-wide VOC limit of 148 tpy. 

No feasible additibeen identified to gas-and oil-fired E

Total - categories covering all 

2011 NEI sources that emit more 

than 25 TPY and ≥ 95% of VOC 

11,254 98.1% 

Total - all other 2011 NEI facilities 

and source categories not included 

above 

215 1.9% Many of these small sources are also controlled 

under the adequate measures in Delaware's SIP. This includes small sources covered by CTG and non-CTG RACT that are established under 7 DE Admin. Code 1124. 

Total 2011 Anthropogenic 

Emissions (TPY)

11,469 100% 
29 

Table 5: NH3 Emission and Control Analysis –NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

Source Category 2011 TPY % of 2011 Inventory Description of Federal Control Measures and Control Measures in Delaware's SIP Potential Add

Animal Husbandry 230 25.0% Delaware regulates Concentrated Animal Feeding 

Operation (CAFO) under State regulations and permitting program that meet the requirements of the federal Clean Water Act (§2202, Title 3 of the Delaware Code. 

No feasible additbeen identified to this source catego

Fertilizers 229 24.9% Not regulated. Regulation of thi

State of DelawarThe only identifithis source catego

of the fertilizer. sufficient market This category is ba national rule.

On-road Mobile 189 20.5% New vehicles must meet California vehicle 

emission standards (CA LEV 3) under 7 DE Admin. Code 1140. New and existing vehicles must be maintained under Delaware’s vehicle Inspection and Maintenance program, 7 DE Admin. Code 1126 and 1131. Extended idling of heavy duty vehicles is prohibited under 7 DE Admin Code 1145. 

Delaware has no further regulate tAside from I/M pidentified measurtransportation cogenerally gain sm

Commercial/ Industrial/ Residential Combustion fired on Gas 

122 13.2% The commercial/institutional fuel combustion 

category includes small boilers, furnaces, heaters, 

and other heating units too small to be considered point sources. The commercial/institutional sector includes wholesale and retail businesses; health institutions; social and educational institutions; and federal, state, and local governments (i.e., prisons, office buildings) and are defined by SIC 

No additional ecocontrol technolog

from this source 
30 

Table 5: NH3 Emission and Control Analysis –NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

codes 50-99. The fuel types included in this source category are coal (SCC 2103002000), distillate oil (SCC 2103004000), residual oil (SCC 2103005000), natural gas (SCC 2103006000), and liquefied petroleum gas (LPG) (SCC 2103007000). Uses of distillate oil and kerosene include space and water heating. Emissions in this category are from many small units throughout the State. NH3 emissions for this source category are not regulated. 

Hay Road 53 5.7% No known ammonia controls for fuel combustion 

Note: ammonia injection to reduce NOx contributes to additional NH3 emissions, but this trade-off is necessary 

Not applicable. 

Residential Wood Combustion 

32 3.5% Delaware does not regulate this category in its SIP. 

It is regulated under 40 C.F.R. Part 60 Subpart AAA New Source Performance Standards (“NSPS”) 

Because all four are significantly bNAAQS, economwould have to be could adopt measunless those meaDelaware is curreAdvance program

voluntarily reduccategories. 

Calpine - Edge Moor (Conectiv) 

11 1.2% This facility is a power plant that consists of three 

gas/oil fired EGUs. (i.e., 86 MW, 174 MW, and 450 MW). Note: Calpine may use urea injection to reduce NOx, but urea contributes to additional NH3

emissions. This trade-off is necessary to reduce NOx for helping meet the ozone NAAQS. 

No feasible additbeen identified to 

these units. 

6 http://epa.gov/ozonepmadvance/index.html
31 

Table 5: NH3 Emission and Control Analysis –NCC 2011 NEI (≥ 25 TPY and ≥ 95%)

However, the urea injection is not needed at the present time. NH3 limits will be established only 

if urea is required to meet NOx emission standards. 

Formosa Plastics 11 1.1% NH3 emissions from this facility are not regulated. No feasible addit

been identified to 

this facility. 

Total - categories covering all 2011 NEI sources that emit more than 25 TPY and ≥ 95% of NH3 

876 95.1% 

Total - all other 2011 NEI facilities and source categories not included above 

45 4.9% 

Total 2011 Anthropogenic Emissions (TPY) 

922 100%