Delaware’s Good Nature depends on you!

STATE OF DELAWARE

DEPARTMENT OF NATURAL RESOURCES

AND ENVIRONMENTAL CONTROL

89 KINGS HIGHWAY

DOVER, DELAWARE 19901

Office of the

Secretary

Phone: (302) 739-9000

Fax: (302) 739-6242

October 28, 2011

Mr. Shawn M. Garvin 

Region 3 Office Administrator

US Environmental Protection Agency

1650 Arch Street

Philadelphia, PA 19103-2029

Dear Administrator Garvin:

In a March 18, 2009 letter Delaware provided the U.S. Environmental Protection Agency 

(EPA) with a timely recommendation regarding designation of areas and the establishment of 

non-attainment area boundaries under the EPA’s March 2008 0.075 parts per million (ppm) 

ozone National Ambient Air Quality Standard (NAAQS) (see Attachment 1). On January 6, 

2010, the EPA extended by one year the deadline under which it was required to finalize area 

designations and establish non-attainment area boundaries while it reconsidered the standard. 

This one-year extension – to March 12, 2011 – represented the latest date that the Clean Air Act 

(CAA) provides for EPA to finalize area designations and boundaries for the 2008 ozone 

NAAQS. We are disappointed that EPA’s decision was ultimately not to change the standard to 

a level more protective of public health in the range recommended by its science advisory board 

(0.060 and 0.070ppm) at this time. 

On September 22, 2011, the EPA announced that it intends to resume the designation 

process for the 0.075ppm ozone NAAQS by issuing “120-day letters” by December 15, 2011. 

Because more than 21⁄2 years have elapsed since Delaware submitted its timely recommendation, 

and more than 7-months have elapsed since the latest date that the CAA provides for the EPA to 

finalize designations and boundaries, Delaware requests the EPA consider in the designation 

process 1) Delaware’s most recent ozone monitoring data, 2) the updated technical information 

and analysis in this letter and in the attached “9-factor analysis” regarding non-attainment area 

boundaries (see attachment 2). Delaware understands that the EPA has agreed to consider such 

information it receives by October 28, 2011.

Regarding Delaware’s most recent ozone monitoring data, as a result of the 

implementation of state and federal control measures the air quality in Delaware has improved 

significantly since our March 2009 letter. Design values for the 2006-2008 period (i.e., the most 
Shawn M. Garvin

October 28, 2011

Page 2

recent at the time of our March 2009 letter) are compared to design values for the most recent 

two years in the table below. 

1

 

County

2006-2008 Design 

Values (ppm) 

2008-2010 Design 

Values (ppm)

2009-20112 Design 

Values (ppm)

New Castle 0.083 0.076 0.077

Kent 0.081 0.074 0.071

Sussex 0.081 0.077 0.076

These recent design values indicate that the air quality in New Castle and Sussex counties 

are not in attainment, and the air quality in Kent County is in attainment relative to the 0.075ppm 

ozone NAAQS. 

Regarding non-attainment area boundaries, the recommendations provided in Delaware’s 

March 18, 2009 letter, and the rationale and analysis provided in that letter have not changed. 

Except as detailed below, this letter and the attached 9-factor analysis are not a replacement for, 

but rather are in addition to the information presented in the March 2009 letter. 

• Revision to Delaware’s Non-Attainment Boundary Recommendation. In the March 18, 

2009 letter Delaware recommended that the following ten (10) states, plus District of 

Columbia (D.C.), be included in a single, large ozone non-attainment area: Delaware, 

Maryland, Michigan, New Jersey, New York, North Carolina, Ohio, Pennsylvania, 

Virginia, and West Virginia. Based on the EPA’s recent Cross State Air Pollution Rule 

(CSAPR) modeling, Delaware is revising this recommendation to include the following 

six (6) additional States: Kentucky, Indiana, Illinois, Missouri, Tennessee, and 

Wisconsin. 

The emissions from these sixteen (16) states plus D.C. are the emissions that are causing 

or contributing significantly to the 0.075ppm ozone non-attainment and maintenance 

problems in and around Delaware, and that continue to cause great harm to public health 

and the economy of Delaware. It is untenable that these other states may be subject to 

less strict air pollution standards than Delaware, when it is the emissions from these 

states that cause Delaware’s attainment problems. When a state has implemented 

necessary controls at great cost to their citizens and industry, all areas that are sufficiently 

near to it so that their emissions contribute to impeded air quality must be subject to the 

same standards. 

• Great Economic Harm and Unfairness is Being Levied on Delaware. Emission controls 

have been established and implemented in Delaware at a great economic cost to 

Delaware citizens and industry. After many rounds of regulation3 Delaware’s sources 

 1 Note that the current ozone design values are at the levels predicted in Delaware’s 2007 Attainment 

Demonstration SIP for the 0.08ppm ozone NAAQS which is currently pending EPA approval. 2 Based on preliminary 2011 data. 3 For example, all Delaware electric generating units (EGUs) have been subject to reasonably available control 

requirements (RACT) in 1995, the OTC NOx Budget Program in 1998, the EPA NOx SIP Call in 2002, the EPA 

CAIR in 2006, and 7 DE Admin Code 1146 in 2008. All Delaware EGUs are now subject to unit specific best 
Shawn M. Garvin

October 28, 2011

Page 3

that cause and contribute to ozone formation (i.e., volatile organic compound (VOC) and 

nitrogen oxides (NOx) emitting sources) are well controlled. Both large and small new 

and modified sources have been subject to costly non-attainment New Source Review 

control and offset requirements for more than two decades. Sources with the potential-toemit either VOC or NOx at levels as low as twenty-five (25) tons per year are subject to 

Title V permitting requirements. Power plants, industrial boilers, consumer products and 

paints are regulated in Delaware at levels far below national levels – and the list goes on. 

While these programs have significantly reduced emissions, they have also been an 

impediment to economic development and have placed Delaware at a competitive 

disadvantage. This is because these other areas that cause and contribute to our air 

quality problems have not been subject to similar requirements, because they have not 

been properly designated non-attainment by the EPA. 

Delaware’s emissions are likely controlled to a much greater level than any other state 

that impacts Delaware’s air quality – yet Delaware’s air quality remains unhealthy 

because of high ozone concentrations. Many studies have shown that the health benefits 

of clean air far outweigh the cost of controls needed to clean the air; typically by more 

than 10:1. Delaware citizens and industry have endured the cost of controls (i.e., 

whammy 1), and despite this have not reaped the economic benefit of clean air (i.e., 

whammy 2) because of uncontrolled emissions generated outside of Delaware’s borders. 

Delaware is being hit by an economic double whammy. 

If the EPA again establishes small, metropolitan based non-attainment areas, Delaware’s 

well controlled sources will undergo another round of costly regulation, and any 

additional emission reductions will come at a high cost, with control strategies generally 

being technology forcing. In contrast, very cost effective emissions reduction 

opportunities outside this small non-attainment area will not be realized, and the 

uncontrolled sources that are contributing to the problem will remain uncontrolled. This 

is unfair, and contrary to the CAA.

• EPA’s Presumptive Approach is Ineffective. Inclusion of Delaware’s three (3) counties 

in a Philadelphia-Wilmington-Trenton non-attainment area, like was done under the 1997 

8-hour ozone NAAQS, would yet again yield ineffective results. The results are 

ineffective because the inclusion of Delaware within this small non-attainment area 

would again subject all of Delaware to another round of CAA non-attainment 

requirements, while all or parts

4 of the following states, whose emissions significantly 

impact the Philadelphia area would not be subject to the CAA non-attainment 

requirements: Illinois, Indiana, Kentucky, Maryland, Michigan, Missouri, New Jersey, 

New York, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia, and 

Wisconsin. 

Establishing boundaries of a non-attainment area in a manner that is designed to address 

any transport issues is a critical first step in the non-attainment process because these 

 available control technology (BACT) controls that were installed at a cost of between $1,200 and $11,000 per ton 

of NOx reduced. In contrast, EPA’s recent CSAPR is based on NOx controls costing $500 per ton of NOx 

reduced. 4 Under EPA’s presumptive approach only a portion of some states have been subject to CAA non-attainment 

requirements. 
Shawn M. Garvin

October 28, 2011

Page 4

boundaries establish the areas that are subject to the CAA emission control requirements. 

Consider the problem we are preparing to solve; air monitors in Delaware and other parts 

of the Philadelphia area are recording ozone concentrations in excess of the 0.075ppm 

ozone standard. Consider the facts that are generally agreed to: 1) VOC and NOx 

emissions cause the high ozone concentrations, and 2) these VOC and NOx emissions are 

substantially generated from within the sixteen (16) state plus D.C. region identified 

above. It is fairly obvious that to solve the problem, the VOC and NOx emissions that 

are causing the problem must be reduced.

The EPA designed an approach to address air pollution by creating small, metropolitanbased non-attainment areas. Unfortunately, it has turned out that this presumptive 

approach that EPA outlined in its policies5 sets up artificial non-attainment area 

boundaries that fail to address the problem on the regional scope that is necessary to 

adequately address the emissions that are causing the problem: 

o VOC and NOx emitting sources within small non-attainment areas are subject to the 

CAA non-attainment requirements, and as a result the VOC and NOx emitting 

sources in these areas become well controlled. 

o However, VOC and NOx emitting sources outside each small non-attainment area 

(i.e., those that EPA has excluded in its narrow metropolitan area approach6) are not 

subject to CAA non-attainment requirements. The EPA has chosen to partially 

regulate a subset of the NOx emitting sources – those sources that in EPA’s judgment 

can be easily regulated at the federal level, where in EPA’s judgment NOx controls 

are “highly cost effective,” and that are in EPA’s judgment located in states that 

“significantly” contribute to non-attainment or maintenance – through rules like the 

Clean Air Interstate Rule (CAIR) and the more recent CSAPR7

. This is very narrow 

criteria, and as a result many of the emitting sources whose emissions contribute to 

the problem remain uncontrolled.

So, under the EPA approach some of the emitting sources that are causing the problem 

are required to be well controlled (i.e., those within the small non-attainment boundaries), 

and some of the emitting sources that are causing the problem are not required to be 

controlled at all (i.e., all of the VOC sources, and many of the NOx sources that are 

outside the small non-attainment boundaries). Worse yet, emitting sources within the 

small-attainment boundaries are subject to higher and higher costs for smaller and smaller 

incremental emission reductions, while highly polluting sources that are contributing to 

non-attainment in the same area because of transport are allowed to continue to operate 

without controls. 

 5 “Area Designations for the 2008 Revised Ozone National Ambient Air Quality Standards,” December 2008 6 EPA’s interpretation of the term “nearby” is not consistent with the CAA relative to the pollutant ozone. For the 

reasons discussed in our March 18, 2009 letter, the term "nearby" must be interpreted consistent with the scale of 

the problem. 7 CSAPR was designed to mitigate transport at the 0.085ppm level. Delaware does not agree that CSAPR mitigated 

the impact at this level, and despite this disagreement, it is a fact that EPA has not even attempted to mitigate any 

impact between 0.075ppm and 0.085ppm.
Shawn M. Garvin

October 28, 2011

Page 5

This problem can be addressed by EPA scrutinizing the approach it has taken to defining 

“nearby” sources, which are supposed to be subject to the same requirements. A more 

workable definition of “nearby” would be whether a source is “near enough to 

contribute” to nonattainment or interfere with maintenance. Delaware appreciates that 

EPA initially took an approach that was narrowly tailored in an effort to see if it could 

reach air quality improvements in that manner. Unfortunately, time has shown that the 

narrow view of “near” needs to be adjusted in a manner that fulfills the intent of the 

Clean Air Act. 

Here is a perfect example to illustrate why the metropolitan area approach is insufficient 

to fulfill the intent of the CAA. On many days the air coming into Delaware and the 

Philadelphia area contains ozone concentrations in excess of 0.075ppm. This means that 

no matter what is done – no matter how high an emission control cost imposed, the ozone 

non-attainment problem cannot be solved because sources outside the area are not 

controlled. And these sources will not be subject to the CAA requirements that require 

them to be controlled because the EPA has made an arbitrary presumption that they are 

not “nearby.” Further, Delaware and other small metropolitan based non-attainment 

areas will continue to endure the economic and public health burden associated with poor 

air quality. This is untenable, and is totally avoidable.

The EPA must establish a large non-attainment area that fully encompasses all areas that 

are “near” enough to be causing the problem. Delaware recommends that its three (3) counties 

(Kent, New Castle and Sussex) be designated non-attainment, and placed in a sixteen (16) state 

(plus D.C.) non-attainment area that consists of the entire states of Delaware, Illinois, Indiana, 

Kentucky, Maryland, Michigan, Missouri, New Jersey, New York, North Carolina, Ohio, 

Pennsylvania, Tennessee, Virginia, West Virginia, and Wisconsin. Establishing a large nonattainment area is required by the CAA, and is the most effective and economical way to address 

the pervasive ozone nonattainment problem in the northeast region. Delaware recommended this 

approach before, as did Maryland and New Jersey as one of their proposed alternatives. 

However, if the EPA chooses to not establish large non-attainment boundaries, we 

request that Delaware be established as a standalone non-attainment area, such that the 

geographical boundaries of the State of Delaware constitute Delaware's ozone non-attainment 

boundaries. This request is based on the facts that Delaware sources are now well controlled, 

and Delaware's ozone nonattainment and maintenance problems are mainly caused by ozone and 

ozone precursors transported into Delaware from upwind states8

. Under this approach the EPA 

would need to commit to develop and implement effective regional controls to completely 

mitigate ozone/precursor transport in the timeframe of Delaware (and other downwind states) 

attainment schedule according to the CAA. Delaware intends to use every tool available to 

ensure unlawful upwind emissions are mitigated. 

Finally, to be clear, under no circumstances should the EPA construe this 

recommendation to imply that Kent County Delaware be designated non-attainment and included 

 8 EPA’s recent CSAPR modeling indicates that about 90% of Delaware’s ozone problem is caused by emissions 

from outside of Delaware. And, the Delaware emissions that contribute to Delaware and downwind states 

attainment and maintenance problems are well controlled under enforceable state and federal requirements.
Shawn M. Garvin

October 28, 2011

Page 6

within any non-attainment area boundaries other than the large non-attainment area or the 

Delaware stand alone non-attainment area, as recommended in this letter. This is because Kent 

County Delaware is not part of the Philadelphia Consolidated Metropolitan Statistical Area 

(CMSA), has very low emissions due to the implementation of state and federal emissions 

control requirements, and has been monitoring attainment for the 0.075ppm ozone NAAQS for 

the past two years (see the table above). 

 

Thank you for your consideration of our recommendations. If you have any question

regarding this letter or our March 18, 2009 letter, or would like to discuss the relevant issues 

further, please contact Mr. Ali Mirzakhalili, Director of our Division of Air Quality, at (302)739-

9402.

Sincerely,

Collin P. O’Mara

Secretary

pc: Ali Mirzakhalili, Director of DAQ-DNREC
JHh A. lVL-\Rl\.EL.i 

CO\' l-l(:'~ (j IZ 

March 18, 2009 

Mr. William T. Wisniewski (3RAOO) 

Acting Regional Administrator 

Region III 

U.S. Environmental Protection Agency 

1650 Arch Street 

Philadelphia, Pennsylvania 19103-2029 

Dear Administrator Wisniewski: 

On March 12, 2i~08, the EPA revised the primary and secondary National Ambient Air 

Quality Standards (NAAQS) for ground-level ozone from the current 0.08 parts per million (ppm) 

to a new 0.075 ppm. 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. It also recommends the placement of Delaware's counties in nonattainment status under the new 0.075 ppm standard in a non-attainment area. 

Area Description and Attainment/Nonattainment Status 

Dela\vare is composed of three counties, namely New Castle, Kent and Sussex, laying 

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

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

part of New Castle 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 southern pOliion of New Castle County, and all of Kent and Sussex Counties. All 

three counties share similar air quality problems with respect to ozone, because the problem is 

predominantly caused by ozone and ozone precursor emissions from upwind states. 

Delaware's ozone monitoring network includes ambient ozone monitors in each of its 

counties (three monitors in New Castle, one monitor in Kent, and one monitor in Sussex). Based 

on 2006 through 2008 ozone monitoring data (i.e., the most recent three years), the 8-hour ozone 
Mr. VliHiam T, Wisniewski 

March 18, 2009 

Page 2 

design values for New Castle, Kent and Sussex counties are 0.083 ppm, 0.081 ppm, and 0.081 

ppm, respectively. Since these design values are all greater than the 0.075 ppm standard, all 

three counties in Delaware should be designated as non-attainment for both the primary and 

secondary 8-hour ozone NAAQS. 

Pla,rement of Delaware's COIU.nties In a Large Nonattainment Area 

Ground-level ozone and ozone precursor emissions are pervasive and readily transported. 

Numerous epidemiological studies conducted during the past decade have revealed that 

prolonged (i.e., 8-hour) exposure to ozone is associated with increased mortality and a range of 

serious morbidity health effects, including aggravation of a variety of respiratory symptoms and 

lung impairment, asthma attacks, respiratory hospital admissions and emergency department 

visits, and cardiovascular problems. This level of ozone concentration is also associated with 

adverse public welfare effects, which include impacts on vegetation, and forest ecosystems, and 

agricultural crop yields. The pervasive nature of ozone, and the serious adverse health and 

welfare effects associated with ozone non-attainment make non-attainment boundary 

determinations criticaL 

Under the 1997 8-hour ozone NAAQS, the EPA included Delaware's three counties in 

the Philadelphia-Wilmington-Trenton Nonattainment Area. In establishing this area the EPA 

relied on their policy presumption of using Consolidated Metropolitan Statistical Area (CMSA) 

boundaries and the prior I-hour nonattainment area (NAA) boundaries as 8-hour nonattainment 

area boundaries, except they also considered the impact of upwind emissions and included Ocean 

County, NJ, despite Ocean County, NJ being part of the New York CMSA. Delaware believes 

that full consideration of upwind contribution when establishing non-attainment boundaries is 

necessary because ozone and ozone precursor emissions are pervasive and readily transported. It 

is important that the emissions that are causing Delaware's ozone problem be subject to the CAA 

non-attainment requirements. 

In its guidance entitled "Area Designation for the 2008 Revised Ozone NAAQS 

(December 4, 2008)," EPA recommends using the Core Based Statistical Area (CBSA) or 

Combined Statistical Area (CSA), similar to the previous CMSA concept, to delineate 

nonattainment boundaries. In the guidance, EPA recognizes that upwind contribution is 

significant, and indicates that "In addition to nearby areas with sources contributing to 

nonattainment, ozone concentrations in a local area may be affected by long-range transport of 

ozone and its precursors (notably nitrogen oxides). In certain parts of the country, such as the 

eastern United States, ozone is a widespread problem." However, in this guidance document 

EPA also indicted that where this is the case, the CAA does not require that all contributing areas 

be designated nonattainment, but only the nearby areas; and that regional strategies, such as 

those employed in the Ozone Transport Region and EPA's NOx SIP Call are needed to address 

the long-range transport component of ozone nonattainment, while the local component must be 

addressed through local planning in and around the designated nonattainment area. The EPA's 

practice being guided by this interpretation has led to a separation bet\veen regional controls and 

local controls, which has been proved to be substantially ineffective in ozone NAAQS strategy 
NIL William T. Wisniewski 

March 18, 2009 

Page 3 

planning and attainment. In particular, this interpretation has led ineffective, insuf±1cient and 

delayed regional controls, and insufficient and even no local controls being installed in many 

areas due to exclusion of many contributing areas/counties in the nonattainment designation. 

Section 107(d)(1) of the CAA defines a nonattainment area as "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 po!1utmt." In the context of a regional 

problem like ozone nonattainment, the term "nearby" must be interpreted consistent with the 

scale of the problem and the nature of the pollutant. For the purposes of solving air quality 

problems associated with pollutants like sulfur dioxide and carbon monoxide, CMSA or 

CBSA/CSA scale boundaries have proven adequate. This is because concentrations of these 

pollutants above the standard are generally driven by emission sources that are very close, 

geographically and do not involve complex atmospheric chemistry. However, this is not the case 

with ozone. Over the past 35+ years, and in particular since 1990, Delaware's local sources of 

ozone precursor emissions have all been well controlled, yet Delaware's air quality remains nonattainment relative to ozone. High ozone concentrations in Delayvare are not driven by emission 

sources that are geographically close, but rather emissions sources that are many miles away. 

Given this, Delaware believes that it is necessary to consider regional transport of ozone and 

ozone precursor emissions in establishing non-attainment area boundaries. More specific 

reasons for this belief include: 

e	 The CBSA/CSA approach is based on census data rather than air-shed monitoring and/or 

analysis data. Census data, in comparison to air-shed data, represents a poor surrogate 

for determining ozone non-attainment boundaries. This is particularly true for areas like 

Delaware that are heavily affected by long-range transport of ozone and ozone precursors. 

•	 Detailed regional air-shed studies have been completed in the past decade or so, such as 

the Regional Oxidant Modeling (ROM) project covering most of the Ozone TranspOli 

Region (OTR) states, the Ozone Transpoli Assessment Group (OTAG) project, the NOx 

SIP Call analysis covering most of the Eastern U.S., and the EPA Clean Air Interstate 

Rule (CAIR) analysis. These studies have demonstrated that the ozone problem is 

transport-driven and regional in scope, rather than localized or confined to the relatively 

small CBSA/CSA domains. 

•	 The studies mentioned above have further demonstrated that individual CBSA/CSA 

based non-attainment areas do not have the ability to achieve attainment regardless of the 

levels of emission controls they implement within their own jurisdictional boundaries. 

Delaware believes that this conclusion should become the cornerstone of good air quality 

planning and policy, statiing with the crucial boundary determinations. 

•	 In many downwind nonattainment areas, including Delaware, the air coming into a 

county is often with ozone concentration greater than 0.075 ppm (i.e., greater than 

NAAQS). Therefore, it becomes impossible for such an area to solve its non-attainment 

problem under its own authority. The CBSA/CSA approach has led to situations where 

many downwind areas are struggling with non-cost-effective controls to reduce ambient 

ozone components that come from upwind areas that are not subject to the reasonable 

emission control requirements. As a result, protection of public health in those 
Mr. William T. Wisniewski 

March 18, 2009 

Page 4 

downwind areas has been severely hindered and delayed because reasonable emission controls 

are not in place in the upwind areas. 

e	 The CBSA/CSA approach has led to stringent controls being implemented within 

individual non-attainment areas. This approach has had success in the OTR toward 

achieving attainment of both I-hour (0.12 ppm) and the current 8-hour (0.08 ppm) ozone 

NAAQS, however, the most success toward attainment of ozone NAAQS in the OTR to 

date is attributable to national measures taken by the EPA, and regional measures 

developed and adopted by the Ozone Transport Commission (OTC) member states. The 

area is also facing with having to implement measures that will provide diminishing 

returns. We are revisiting standards for a second or third time for sectors that go 

uncontrolled in the contributing upwind states. 

In its December 4, 2008 guidance, EPA recommends nine factors for states to use to 

justify their boundary recommendations. The EPA states its rationale for recommending these 

factors as being that they are similar to the ones used to establish CBSAs and CSAs. Delaware 

believes, however, using these factors to justify ozone non-attainment boundaries because they 

are similar to the ones used to establish CBSAs and CSAs is not appropriate. Instead, boundary 

recommendations must be evaluated with consideration given to the pervasive nature of the 

pollutant ozone, and the ozone/precursor transport issue discussed above. 

Based on the above discussion Delaware recommends that EPA include Delaware's three 

counties in a single multi-state regional large nonattainment area (NAA) that includes all 

counties in the states of Maryland, Michigan, New Jersey, New York, North Carolina, Ohio, 

Pennsylvania, Virginia, and West Virginia. This area encompasses the emissions that are 

causing Delaware's ozone non-attaimnent problems, and rationale for it is more fully described 

in the CAA Section 126 petition that Delaware submitted to the EPA on December 15, 2008. A 

map that details Delaware's recommended nonattainment area boundaries is attached to this 

letter. Delaware believes that this approach would: 

•	 Reinforce the science-based and wide-accepted fact that ozone non-attainment IS a 

"regional problem" and not only a "local problem"; 

•	 Include all or most of the counties necessary to solve this regional problem, give them a 

vested interest in solving this regional problem, and foster cooperative development and 

implementation of control strategies that are most effective to solving the wide-spread 

ozone nonattaimnent problem; 

•	 Remove political barriers and level the playing field by setting the consistent baseline of 

control requirements of Subpart 2 of Title I, Part D of the CAA within the region, which 

include New Source Review (NSR), vehicle Inspection and Maintenance, and highly 

cost effective Reasonably Available Control Technology (RACT) requirements; 

•	 Effectively compliment national and regional rules that address regional transport; 

•	 Greatly simplify and provide equity to the process of implementing the new 8-hour 

NAAQS. 
My. William T.Wisniewski 

March 18, 2009 

Page 5 

implementation of control strategies that are most effective to solving the wide-spread 

ozone nonattain:ment problem; 

1;1 Remove political barriers and level the playing field by setting the consistent baseline of 

control requirements of Subpart 2 of Title I, Part D of the CAA 'vvithin the region, which 

include New Source Review (NSR), vehicle Inspection and Maintenance, and highly 

cost effective Reasonably Available Control Technology (RA.CT) requirements; 

Effectively compliment national and regional rules that address regional transport; 

til Greatly simplify and provide equity to the process of implementing the new 8-hour 

NAAQS. 

Delaware believes that the above large-NAA recommendation represents the most 

effective and economical way to address the pervasive ozone nonattainment problem in the 

northeast region. If, however, the EPA chooses not to embrace the above recommendation (i.e., 

not to fully consider upwind contribution in setting nonattainment boundaries, and not to 

establish a large regional ozone non-attainment area), despite our confidence that is a better 

course of action, then Delaware proposes that the EPA establish Delaware as a stand-alone ozone 

nonattainment area (i.e., the geographical boundaries of Delaware constitute Delaware's ozone 

nonattainment boundaries). Delaware suggests this stand-alone alternative not because it is the 

best approach to clean the air, but rather because it is more rationale than a CBSA/CSA 

supported designation under the muse that emissions within the CBSA/CSA area are causing the 

nonattainment problem. Note that Delaware's ozone nonattainment problems are mainly caused 

by long-range ozone/precursor transport from upwind sources, and under this approach the EPA 

would need to commit to develop and implement effective regional controls to completely 

mitigate ozone/precursor transport in the timeframe of Delaware (and other downwind states) 

attainment schedule according to the CAA. 

Thank you for your consideration of the above recommendations. If you feel you cannot 

support the large non-attainment boundary approach discussed above Dela'vvare would like to 

have an opportunity to continue this discussion before you propose any modification. If you 

have any questions concerning this submittal or would like to discuss it further, please contact 

rvlr. Ali Mirzakhalili, the administrator of our air quality management section, at (302)739-9402. 

Sinc.erelv.")''.(

/T}/Ij -~.__. ~Vv

Jack A. Markell 

Governor 

pc: Dave Small 

Jim Werner 

Ali Mirzakhalili 

Judith Katz 
Mr> V'/iHiam T> "NlSIlie'Nski 

March 18, 2009 

Page 6 

Delaware Recommendation of Large
 

NDiilattainment Area BmUlldaries for the 2008 Revised Ozone NAAQS
 

Delaware Recommended 8~hour Ozone Non5 attainment Boundaries 

North Carolina 

New York 
1 

Attachment 2 

Supplemental Information to Delaware’s Ozone Non-Attainment Boundary 

Recommendation Letter to US EPA on 10/28/2011 

The 9-Factor Analyses 

For Designation of Nonattainment Area Boundaries for the 0.075 ppm 

Ozone NAAQS 

As a framework for area-specific analyses, the EPA has recommended that states and 

tribes base their boundary recommendations on an evaluation of the following 9 factors: 1 air 

quality data, emission data, population density and degree of urbanization, traffic and 

commuting patterns, growth rates and patterns, meteorology, geography and topography, 

jurisdictional boundaries, and level of control of emission sources. These factors are 

consistent with those used in the designation process for the 1997 ozone standard and are 

factors EPA plans to consider in evaluating and making decisions on the nonattainment area 

boundaries for the 2008 0.075 ppm ozone standards. Additionally, states and tribes may 

identify and evaluate other relevant factors or circumstances specific to a particular area. 

Delaware hereby provides some detailed discussions and analyses on those 9 factors. 

The approach that Delaware follows in the discussions is (1) to see if the factor(s) would 

have a direct relation with the ambient air quality and ozone precursor emissions, (2) to 

assess if the factor(s) could lead to meaningful and reasonable designation results, and (3) to 

evaluate that the designation results would lead to effective future controls to reduce 

emissions and to mitigate upwind transport. As indicated in the discussions and analyses 

below, Delaware strongly suggests that EPA consider the 9 factors together with their 

relations with, effects on, and contributions to ambient air quality and to ozone/precursor 

transport. The lessons in the past decade or so have shown that these factors, if not 

considered closely together with the large-scale nature of the ambient ozone (or, its 

association with the large-scale air-shed) and the transport issues, could not make much 

practical sense in nonattainment area (NAA) designation. A few factors may not be directly 

related to the transport issues, and Delaware believes that these factors are more applicable to 

developing proper control strategies for specific counties or zones within the non-attainment 

area after a large non-attainment area boundary is established. 

1. Air quality data 

 The ambient monitoring data continuously show that the 8-hour ozone nonattainment 

is a large-scale or regional problem. Table 1 below is a list of the 2008-10 design values of 

northeastern and mid-western states,2

 most of them are in the Delaware recommended large

NAA. 

 

1 Memorandum: Area Designations for the 2008 Revised Ozone National Ambient Air Quality 

Standard; Robert J. Meyers, Principal Deputy Assistant Administrator, US EPA, December 4, 2008. 

2 EPA’s Air Quality System (AQS) data query (6/27/2011); a complete list is at 

http://www.epa.gov/airtrends/values.html..
2 

 

 Table 1. Northeastern and Mid-Western States 2008-10 Design Values* 

State 2008-10 Design Value (ppm) 

Connecticut 0.081 

Delaware 0.077 

District of Columbia 0.079 

Illinois 0.074 

Indiana 0.073 

Kentucky 0.075 

Maryland 0.089 

Massachusetts 0.077 

Michigan 0.075 

Missouri 0.077 

New Jersey 0.081 

New York 0.084 

North Carolina 0.082 

Ohio 0.079 

Pennsylvania 0.083 

Rhode Island 0.076 

Tennessee 0.077 

Virginia 0.081 

West Virginia 0.073 

Wisconsin 0.078 

*The values are the highest 2008-10 design values of individual states. 

 The data in Table 1 indicate clearly that almost all northeastern states are to be in 

non-attainment status under the 0.075 ppm ozone standard. In addition, EPA’s Air Now 

maps clearly show that on many days ozone episodes are broad in nature, covering much of 

the mid-west and eastern portions of the U.S. Very few ozone episodes are observed as 

being limited in scale to metropolitan areas. Therefore, Delaware believes that ambient air 

quality is not a local factor and must be considered on a regional basis in the upcoming 

designation process. 

 

 Due to its regional nature, the air quality with respect to ozone in a downwind 

CBSA/CSA (core based statistical area/combined statistical area) is significantly affected by 

upwind sources and therefore can be significantly improved by regional controls. Figure 1 

presents the design values of all monitors in the Philadelphia-Wilmington-Atlantic City 

nonattainment area in the past decade or so. The data in Fig. 1 indicates that the air quality 

within the Philadelphia CBSA-based NAA has been significantly improved by the regional 

control of NOx SIP Call, which became effective in 2003-2004 timeframe.3

 

 

3 Note that this does not indicate that establishment of small metropolitan based non-attainment areas, coupled 

with programs like CAIR and CSAPR are allowed by the CAA to address ozone nonattainment. To the 

contrary, this clearly shows that ozone non-attainment problem is broad, reductions over a broad area work. 

The CAA requires this broad area to be subject to the CAA non-attainment requirements. Regional control 

programs like CAIR and CSAPR address EGUs, but leave many cost effective controls that can be applied to 

other source categories on the table. And, because of this, downwind states are put at a disadvantage by being 

forced to adopt higher cost control measures to compensate for the lack of cost effective upwind controls. 
3 

The data in Fig. 1 also indicates that all of the monitors in the Philadelphia area move 

together, meaning that when one monitor is recording high ozone concentrations all monitors 

in the region are recording high concentrations. This same pattern is, generally, observed 

beyond the Philadelphia area, which indicates that the ozone problem and emission that are 

driving the ozone problem are occurring over a large area. 

The air quality data within a CBSA/CSA, if not interpreted with consideration given 

the transport of ozone and its precursors, would lead to improper or contradictory 

conclusions and ineffective control strategy. For example, ambient ozone concentrations at 

Fair Hill monitor, Cecil County, Maryland, has been among the highest in the Philadelphia 

NAA. Historically, Cecil County has been included in the Philadelphia NAA based on those 

monitored air quality data. However, the air quality around the Fair Hill monitor is believed 

to be predominantly affected by emission sources outside the county, with the exception of 

mobile emissions along Interstate Highway 95. Emission inventory review indicates that 

there are no major point and area sources in Cecil County, and non-road activity level is 

relatively low. In addition, emissions, population density, traffic patterns, and growth rates 

and patterns in Cecil County are all different from some major metropolitan counties in the 

Philadelphia NAA. Designating Cecil County as part of a small non-attainment area, like the 

Philadelphia nonattainment area, based solely on its monitored air quality data is contrary to 

conclusions from analyses of those additional factors. EPA’s CAIR and CSAPR modeling 

both confirm that many upwind states, Illinois, Indiana, Kentucky, North Carolina, 

Tennessee, Pennsylvania, New Jersey, Maryland, New York, Ohio, Virginia and West 

Virginia, contribute significantly to the violating air quality in Cecil County. Additionally, 

placing Cecil County within a small non-attainment area, like the Philadelphia NAA, and not 

including the upwind states that are causing/contributing to the problem, will not lead to any 

effective controls in those upwind states and will therefore not address the problem. 

The Fair Hill monitor in the example above is not a unique case. Analyzing most 

other ozone monitors in the eastern half of the United States will lead to a similar conclusion, 

that is, upwind emissions and transport is a driving force of the high ozone concentrations 

detected in many downwind states’ monitors. 

Fig. 1 Philadelphia Ozone Non-Attainment Area 8-Hour Ozone Design Value Trend 

 

Regional programs like CSAPR are good, and they can help states mitigate their impact on downwind areas, but 

they are not a substitute for establishing proper ozone non-attainment area boundaries. 
4 

 

Analysis of the “air quality data” factor indicates that the area that many monitors 

throughout the eastern half of the United States are violating the 0.075ppm ozone standard. 

Analysis of the “air quality data” factor also indicates that the ozone precursor emissions 

over a large, contiguous area have a direct relation with the ambient air quality throughout 

the area, and the emissions cause and contribute to this large-scale non-attainment. Delaware 

concludes that because the area violating the standard is large, and because the nearby 

emissions from a large area are the cause of the violations, the air quality data supports the 

establishment of large non-attainment area boundaries, and the establishment of these 

boundaries would lead to effective future controls to reduce emissions and to mitigate 

upwind transport. 

2. Emissions data (location of sources and contribution to ozone concentrations) 

 Emission sources in one county or CBSA/CSA have been proven to contribute not 

only to local or close-by ambient ozone concentrations but also to ozone concentrations in 

many downwind areas far away from the sources. This factor has been extensively studies in 

the past decade or so. For example, both NOx SIP Call study and EPA’s CAIR/CSAPR 

modeling analyses have shown that major point sources such as EGUs in many counties 

upwind of OTR have significant contributions to OTR’s ozone nonattainment problems 

under the 1997 0.08 ppm ozone standard and the 2008 0.075 ppm ozone standard. Many of 

those upwind counties, however, have not been classified as nonattainment with respect to 

the relevant standards. Therefore, this factor must be considered in the designation process 

closely together with the transport issues, so that major emission sources in the upwind states 
5 

can be properly controlled under the 0.075 ppm ozone standard. A detailed example analysis 

for this factor follows. 

Using the same methodology EPA used in their recent CSAPR modeling analysis, 

Delaware concludes that at least one monitor in the Philadelphia NAA are significantly 

affected, relative to the 0.075ppm ozone standard, by emissions in the following states: 

 Delaware 

 Illinois 

Indiana 

Kentucky 

Maryland 

 Michigan 

 Missouri 

 New Jersey 

 New York 

 North Carolina 

 Ohio 

 Pennsylvania 

 Tennessee 

 Virginia 

 West Virginia 

 Wisconsin 

It should be pointed out that 11 of the above 16 states are over hundreds of miles 

away from the small, CMSA-based Philadelphia NAA that EPA has established to address 

prior ozone standards, and their emission sources are still making significant contributions to 

the Philadelphia NAA’s ozone nonattainment problem. It becomes very clear that these 

upwind emissions must be considered in the designation process so that their impacts on 

Delaware and other downwind states can be addressed properly and effectively later. 

Our modeling experience with CALGRID v2.45, a photochemical model designed as 

an OTC Platform, provided useful information on the impacts of other states on the OTR. A 

zero-out modeling conducted by zeroing out all anthropogenic emissions in OTR for July 6-

23, 2002 meteorological episode informs us that the OTR is likely to receive transported 

ozone, especially the southern OTR region, at levels higher than the current ozone NAAQS 

(see Figure 2 below). 

Fig. 2. Result from CALGRID v2.45 Modeling for Zero-out Emission Scenario 
6 

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170

0

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Maximum 8-Hour Ozone Concentrations

Zero Out Anthropogenic Emissions in the OTR

CALGRID 2.45 Modeling Domain - July 6-23, 2002

Ozone

Concentrations

(PPB)

10/17/11

 In addition, emission source locations and their contributions to ozone formation 

within a CBSA/CSA vary significantly, which further disqualifies, rather than supports, the 

CBSA/CSA-based nonattainment designation approach. More analyses and discussions of 

Delaware’s three counties, a part of the CBSA/CSA-based Philadelphia NAA, are provided 

in the next section. 

The above analysis of emission data together with the regional nature of air quality 

clearly demonstrates that emissions of local sources in many upwind states not only cause 

local air quality problems but also contribute significantly to ozone air quality problems in 

many downwind states. The transported ozone and its precursors are the root of the 

widespread regional ozone non-attainment situation in the northeastern U.S. Upcoming 

designation of ozone non-attainment area boundaries must not be based on a source’s locality, 

but on a source’s impact and contribution to the regional non-attainment situation. 

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

 Population and urbanization usually show similar levels in the cities and counties 

within a CBSA/CSA, and have a significant impact on daily-activity based emissions and 

local traffic emissions. Also, they may or may not, have a direct relation with major point 

sources. For example, some mega power plants are located in areas far away from urban 

centers and even outside a CBSA/CSA. Delaware believes that this factor must be analyzed 

with consideration given to together with other factors and the transport issues. A high 

population density or degree of urbanization is a driver of significant activity based 

emissions and local mobile source emissions, and these emissions contribute to ozone and 
7 

ozone precursor concentrations in downwind states, the same way that power plants and 

other industrial sources contribute. Delaware believes that this factor should not be 

considered alone in establishing non-attainment area boundaries. Rather this factor should be 

given much consideration in the design of control strategies within large non-attainment 

boundaries. 

 The population and urbanization, as well the traffic patterns (Factor 4) and the growth 

rates/patterns (Factor 5), are closely related to the air quality factor (Factor 1) and the 

emission factor (Factor 2). They have to be analyzed together. The following analysis is 

based on data from Delaware 2002 emission inventory (the most recent State Implementation 

Plan (SIP) inventory), and will provide demonstrative examples and some insight discussions 

of how these factors (i.e., population, urbanization, and traffic patterns) are related to the 

emission factor and the air quality factor. In a later section (Factor 5, Growth), the relation of 

population and growth will be discussed. 

 Table 2 is the demographic data from Delaware’s 2002 SIP inventory. Table 3 is the 

emission data for the three counties from the 2002 SIP inventory. Table 4 is the countywide 

total emission densities, where the total emission of a county is the sum of emissions from all 

source sectors in the county (i.e., point, non-point, non-road mobile and on-road mobile 

sectors). The emission densities are defined in two terms, one by population in TPD (tons per 

day) emission per 10,000 population, and one by land area in TPD per 10 square miles. 

Table 2. Demographic data of Delaware’s three counties.* 

Demographic Parameter Kent New Castle Sussex

Population 131,069 512,360 163,946

Households 49,127 191,787 66,471

Land Area (square miles) 594 439 950

Annual VMT (million miles) 1,406 5,338 2,091

Population Density per sq. mile** 221 1167 173

*Data from Delaware 2002 SIP Emission Inventory. 

** Not in the original 2002 SIP Inventory, but calculated from the data in Table 2. 

Table 3. Ozone precursor emissions in Delaware’s three counties.* 

County VOC, TPD NOx, TPD

Kent 16.86 34.50

New Castle 58.66 107.22

Sussex 40.02 57.37

*Data from Delaware 2002 SIP Emission Inventory. 

Table 4. Countywide total emission density.* 
8 

VOC Emis. NOx Emis.

County TPD/10000cap. TPD/10sq.mile TPD/10000cap. TPD/10sq.mile

Kent 1.29 0.28 2.63 0.58

New Castle 1.14 1.34 2.09 2.44

Sussex 2.44 0.42 3.50 0.60

* Total emission of a county is the sum of emissions from all source sectors in a county, as shown in 

Table 3. 

 An initial review of data in Table 2 and Table 3 indicates that the total emissions from 

Delaware’s three individual counties follow relatively well the patterns of their populations, 

households and annual VMT (vehicle miles traveled), that is, New Castle is the highest, 

followed by Sussex, and then Kent. However, more careful review of the data, plus those in 

Table 4, reveals that these data can provide other meaningful indications for the NAA 

designation. 

 First, both VOC and NOx emissions in New Castle are significantly higher than those 

in Kent and Sussex. In addition, New Castle has the smallest land area, which makes its 

area-based emission densities are 3 to 4 times as big as those in Kent and Sussex (Table 4). 

However, the 2008-10 design value (DV) of New Castle is 0.076 ppm, while the 2008-10 

DVs of Kent and Sussex are 0.074 ppm and 0.077 ppm, respectively. In other words, the 

ambient ozone concentration in New Castle is not significantly different from those in Kent 

and Sussex, even though New Castle County bears much heavier VOC and NOx emission 

loads from local sources. This fact can reasonably lead to the conclusion that the air quality 

in Delaware must not be determined by its own population distribution, urbanization patterns, 

and local emissions, but rather by impacts from factors outside Delaware’s boundary, in 

particular, ozone and its precursors transported from upwind states or areas. 

 Second, Table 4 shows that Sussex has population-based emission densities much 

higher than those of New Castle and Kent, although Sussex is a less urbanized county. The 

indication is that there are significant major emission sources in Sussex that are not 

proportional or compatible to its population and urbanization pattern (See also analyses of 

Tables 5, 8 and 9 below). This indication strongly suggests that the population-urbanization 

factor be closely considered together with the emission data, specifically, using the 

population-based emission density, in the upcoming NAA designation process. If not, 

Delaware believes that many upwind counties would be left once again outside NAA, which 

would make many major sources in those counties escape again from the next round of 

control efforts, thus consequently sabotaging and delaying the attainment process of the 

0.075 ppm ozone NAAQS. 

 Table 5 presents the countywide point source emission density data for the three 

counties in Delaware. Again, Table 5 shows that Sussex has much higher population-based 

VOC and NOx emission densities than New Castle and Kent. The data in Table 5 helps 

explain the higher total emission densities of Sussex in Table 4, that is, Sussex has major 

point sources for both VOC and NOx that are not compatible to its population and 

urbanization level. Delaware wants to point out that (1) those major point sources have been 
9 

identified in Sussex (Maritrans lightering operation as the major VOC point source, and 

Indian River power plant as the major NOx point source) for decades, (2) Delaware had 

difficulties in implementing effective controls on those sources under the 1-hour ozone 

standard since Sussex was not designated as a severe nonattainment area under the 1-hour 

standard, and (3) after Sussex was classified as nonattainment area together with Kent and 

New Castle in 2004, emission control efforts in Sussex has become streamlined with those in 

Kent and New Castle, and timely and stringent controls have been implemented to control 

emissions from those sources (for Maritrans, Regulation 1124.46 became effective in May 

2007, and for Indian River plant, Regulation 1146 became effective in December 2007). The 

experience indicates clearly that including a rural county with a small population but major 

emission source(s) in a NAA can significantly enhance and streamline implementation of 

effective controls in the NAA. 

Table 5. Countywide point source emission density. 

VOC Emis. NOx Emis.

County TPD/10000cap. TPD/10sq.mile TPD/10000cap. TPD/10sq.mile

Kent 0.04 0.01 0.39 0.09

New Castle 0.18 0.21 0.86 1.00

Sussex 0.82 0.14 1.52 0.26

Table 6 presents the countywide non-point source emission density data for the three 

counties in Delaware. The non-point source emissions (formerly termed as area source 

emissions) are mainly derived from human-activity levels. Therefore, activity level, 

population density and degree of urbanization will be reflected in the non-point source 

emission density. In Table 6, population-based emission densities of both VOC and NOx are 

more or less the same for all three counties in Delaware, indicating that the related activity 

levels are about the same throughout Delaware. However, area-based emission densities in 

New Castle are much higher than those in Kent and Sussex, reflecting the higher activity 

density in New Castle County (i.e., more people engaging in the same activity on a unit area). 

Table 6. Countywide non-point source emission density. 

VOC Emis. NOx Emis.

County TPD/10000cap. TPD/10sq.mile TPD/10000cap. TPD/10sq.mile

Kent 0.44 0.10 0.03 0.01

New Castle 0.39 0.46 0.04 0.04

Sussex 0.45 0.08 0.05 0.01

Table 7 presents the countywide non-road mobile source emission density data for the 

three counties in Delaware. Since a significant portion of non-road mobile emissions is also 

activity-derived, a discussion similar to Table 6 will apply to Table 7. For example, areabased emission densities in New Castle are much higher than those in Kent and Sussex, 

reflecting the higher activity density in New Castle (i.e., more people engaging in the same 
10 

activity on a unit area). In addition, Table 7 shows that the population-based emission 

densities in both Kent and Sussex are higher than that in New Castle. Possible explanations 

include (1) more agricultural equipments being operated in Kent and Sussex, (2) more marine 

vessel activities in Kent and Sussex, (3) more recreational non-road activities in Sussex 

County, and (4) intensive Air Force Base activity in Kent County. 

Table 7. Countywide non-road mobile source emission density. 

VOC Emis. NOx Emis.

County TPD/10000cap. TPD/10sq.mile TPD/10000cap. TPD/10sq.mile

Kent 0.39 0.09 1.15 0.25

New Castle 0.24 0.28 0.48 0.56

Sussex 0.57 0.10 0.80 0.14

 Table 8 presents the countywide annual VMT (vehicle miles traveled) density data for 

the three counties in Delaware. Table 9 presents the countywide on-road mobile source 

emission density data for the three counties in Delaware. The data in these two tables reveals 

some meaningful messages. 

Table 8. Countywide annual VMT density. 

Kent New Castle Sussex

VMT/Population, 1000mile/cap. 10.7 10.4 12.8

VMT/Household, 1000mile/Hshd 28.6 27.8 31.5

Table 9. Countywide on-road mobile source emission density. 

VOC Emis. NOx Emis.

County TPD/10000cap. TPD/10sq.mile TPD/10000cap. TPD/10sq.mile

Kent 0.42 0.09 1.07 0.24

New Castle 0.33 0.39 0.71 0.83

Sussex 0.61 0.10 1.13 0.19

First, Table 8 shows that the population VMT density and the household VMT 

density are very close in Kent and New Castle, but significantly higher (>10%) in Sussex. 

Explanations may include that (1) a significant portion of VMT in Sussex is created by 

outstate and out-county drivers who are traveling to the highly attractive beach areas in 

Sussex (Lewes Beach, Rehoboth Beach and Bethany Beach), (2) outstate and out-county 

drivers in Kent (those by-passing drivers to Sussex and commuters to New Castle) also 

contributes to Kent’s VMT, but not as significantly as to Sussex’s, (3) outstate drivers in 

New Castle (such as those on I-95) contribute to New Castle’s VMT as well, but the much 

higher population and household numbers of New Castle make the contribution less 

significant or less noticeable, and (4) the explanations in (2) and (3) help explain why Kent 

and New Castle have similar population and household VMT densities. 
11 

Second, Table 9 shows that New Castle has a much higher area-based on-road mobile 

emission density, reflecting its more urbanized nature, i.e., many more drivers within a unit 

area. However, Table 9 also shows that New Castle has the lowest population-based on-road 

mobile emission density, followed by Kent, while Sussex has the highest. The implication of 

this set of data is that vehicles in New Castle have average VOC and NOx emission rates 

lower than those in Kent and Sussex. Explanations may include the following. 

• New Castle has the most stringent on-road mobile source controls due to its 

nonattainment status and the relevant transportation planning requirements under the 

associated transportation conformity requirements. 

• Sussex has the least stringent controls on on-road mobile sources. Historically, 

Sussex was not designated as a severe NAA under the 1-hour ozone standard. In fact, 

a less stringent vehicle inspection and maintenance (I/M) program was still in effect 

in Sussex when the 2002 emission inventory was compiled. 

• Outstate vehicles from “attainment counties” have contributed significantly to Kent 

and Sussex’s VMTs (see the discussion in the previous paragraph). Those vehicles 

are not subject to stringent inspection and maintenance requirements in their home 

counties and are very likely to have higher emission rates. A preliminary review of 

attainment or nonattainment statuses of the Delmarva Peninsula under the 1997 0.08 

ppm standard indicates that all counties adjacent to Kent and Sussex to the west and 

to the south are in attainment status. It can be reasonably assumed that proper 

inspection and maintenance programs do not exist in those counties. Vehicles from 

those counties, however, are constantly visiting Kent and Sussex, and very likely 

bringing up vehicle emission rates in Kent and Sussex. 

The above discussion on on-road mobile emission densities has a meaningful 

indication, that is, vehicles from adjacent “attainment counties” may contribute significantly 

to VMTs and on-road mobile emission loads in the neighboring nonattainment counties. To 

reduce the VMT contribution seems unfeasible (e.g., Delaware cannot and will not prohibit 

those outstate vehicles from running on Delaware’s land). However, it should be reasonable 

and fair for the affected counties (e.g., Kent and Sussex) to expect those contributing 

counties to implement adequate I/M programs for their vehicles. One feasible way is that 

EPA could place those contributing counties under the same nonattainment and 

transportation conformity requirements. 

 In summary, the analysis of this factor for the three counties in Delaware has 

demonstrated that population and urbanization levels, which are believed to be good 

indicators for defining CBSA/CSA, and good factors for designing control strategies within a 

non-attainment area, are not good factors in designating attainment or nonattainment areas, or 

establishing non-attainment area boundaries for the 0.075 ppm ozone standard. 

4. Traffic and commuting patterns 
12 

 Traffic and commuting patterns usually show similarities in cities and counties with 

similar rural or urban patterns, such as within a CBSA/CSA. Their relations with local onroad mobile emissions seem to be more apparent or more easily identified on a local scale, as 

discussed in Factor 3 above. Delaware believes that it is not appropriate to consider traffic 

activities and commuting patterns solely in a local scale, while ignoring their connections 

with the regional ozone non-attainment problem. 

National, regional and local emission inventory data have shown for many years that 

the on-road mobile source emissions remain a major portion of an area’s or county’s total 

emission inventory. Consequently, mobile source emissions from upwind areas/counties 

continue contributing to the ozone nonattainment problems in the downwind states through 

transport of ozone and its precursors. Therefore, it is imperative that EPA continue 

implementing stringent national/regional rules and emission limits on vehicles so that their 

impacts on downwind states can be effectively mitigated. On the other hand, improvements 

in traffic and commuting patterns are important to reduce the total emission load within an 

area, and its contribution to downwind areas. Delaware believes that this factor should not 

be considered as a decisive factor as used in defining CMSA r CSA. Instead, it would be 

more applicable for state/county/city authorities to develop local traffic management 

strategies after regional nonattainment areas are established. 

 

5. Growth Rates and Patterns 

The growth and development of an area can be reflected in various demographic and 

economic aspects, such as population and household growths, urbanization development, 

employment increase, and local GDP (gross domestic product) growth. The discussions in 

Factor 3 (Population and Urbanization) have provided some analyses on static population and 

urban data (i.e., one year data) and their relations with the emission data. This section 

provides discussions on dynamic demographic and economic data (i.e., growth). 

First, Delaware believes that local (or state) demographic and economic growth data 

should be analyzed with regional and even national data. Table 10 presents some population 

estimates extracted from the US Census Bureau March 2011 Release.4

 According to the data 

in Table 10, the population growth rate in Delaware between 2000 and 2010 is the biggest 

among the neighboring states. However, the absolute number of population increase in 

Delaware is the smallest. During this period, the population increases in Maryland, New 

Jersey and Pennsylvania are approximately 3 to 4 times as many as that in Delaware. 

Table 10. Population estimates of Delaware and neighboring states. 

 Population Counted 2000-2010 Change 

 2000 2010 Number % 

Delaware 783,600 897,934 114,334 14.6%

 

4 Population Distribution and Change: 2000 to 2010. U.S. Census Bureau, U.S. Department of 

Commerce, March 2011: http://www.census.gov/prod/cen2010/briefs/c2010br-01.pdf. 
13 

Maryland 5,296,486 5,773,552 477,066 9.0%

New Jersey 8,414,350 8,791,894 377,544 4.5%

Pennsylvania 12,281,054 12,702,379 421,325 3.4%

United States 281,421,906 308,745,538 27,323,632 9.7%

 

In addition, the population growth data does not reflect the actual economic 

development. In the past few years, GDP for Delaware has experienced its ups and downs, 

but the overall GDP growth in Delaware has lagged behind the US GDP growth. For 

example, Delaware’s GDP fell by 4.8% in 2007-2008, increased by 2.1% in 2008-2009, and 

then increased again by 1.3% in 2009-2010.5 The GDP data for the neighboring states for the 

past years are not readily available. However, the most recent available data from the Bureau 

of Economic Analysis show that the GDP growths for Delaware, Maryland, New Jersey, 

Pennsylvania, and US in the 2009-2010 period are 1.3%, 2.9%, 2.5%, 3.0%, and 2.6%, 

respectively.6 Apparently, Delaware’s GDP growth is lower than those of its neighboring 

states and the national average. Therefore, from the economic development viewpoint, 

Delaware should not be designated as nonattainment area along with its neighboring states. 

Second, Delaware believes that population and economic growth do not necessarily 

have direct relations with local emission changes and the ozone/precursor transport. Since 

1990, ozone NAAs like Delaware have been required to reduce their VOC and/or NOx 

emissions not only to offset their economic growths but also to meet the stringent RFP 

(reasonable further progress) and AD (attainment demonstration) provisions in the CAA. To 

achieve such significant emission reductions, Delaware and other NAAs have implemented 

numerous controls within their boundaries, including many regional, NAA-wide, and local 

controls. On the other hand, areas and counties throughout the country with attainment or 

marginal nonattainment statuses have implemented minimum local controls over their 

emission sources. Those areas/counties have enjoyed their economic growths, but have not 

done much to reduce their emissions to offset such economic growths. The fact is, however, 

emissions from those counties have been, and will continue to be, parts of upwind 

contributions to downwind ozone nonattainment problems. 

Third, economic growth of an area or county does not necessarily have a direct 

relation with its ambient ozone air quality. Since 1990, the nationwide ozone ambient air 

quality has been continuously improving along with the nation’s economic growth. This 

improvement in ozone air quality has been believed to be one of the greatest achievements of 

the CAA since it has mandated or laid foundation for the following: (1) federally-mandated 

national controls such as standards over vehicle emissions and fuels, (2) regionally-adopted 

controls to address ozone and/or its precursor transport such as NOx SIP Call and model 

rules of OTR states, and (3) countless controls over emission sources within NAAs. The 

 

5

The 2010 Delaware Annual Economic Report, Delaware Department of Labor, September 2011.

6 Economic Recovery Widespread across States in 2010, Advance Statistics of GDP by States. Bureau 

of Economic Analysis, US Department of Commerce, June 2011: 

http://www.bea.gov/newsreleases/regional/gdp_state/gsp_highlights.pdf. 
14 

ambient ozone air quality in many counties with an “attainment” status under the previous 1-

hour standard (0.12 ppm) and the 1997 standard (0.08 ppm) has been improving as well. 

In general, higher growth rates and uncontrolled urban development patterns (i.e., 

sprawling) are thought to be associated with increases in emissions and deterioration in 

ambient air quality. However, in order to connect the growth factor with the ozone 

nonattainment designation, a comprehensive analysis, which is much broader beyond a state 

scale, would be needed. Therefore, Delaware believes that the growth factor should not 

influence much in the upcoming NAA designation process, unless a comprehensive and indepth analysis together with other factors (such as Factor 1, ambient air quality, and Factor 2, 

emission data) and the transport issues could be conducted in a regional and national scale. 

Delaware thinks that this factor would be more applicable for developing local control 

strategies to manage economic growth and urban planning after nonattainment areas are 

established. 

6. Meteorology (weather/transport patterns) 

 There are many components in meteorology, such as precipitation, cloud coverage, 

solar radiation, temperature gradients and wind, which affect ozone formation and transport. 

Extensive studies have been done on effects of meteorological components on ozone 

formation and transports, and the results are consistently supporting the vast range of the 

ozone problem and its transport (see “The Nature of the Ozone Air Quality Problem in the 

Ozone Transport Region: A Conceptual Description,” Final Report by NESCAUM, October 

2006; “A conceptual Model for Ozone Transport,” by Dr. Robert Hudson, University of 

Maryland, January, 2006; and “A Guide to Mid-Atlantic Regional Air Quality,” by 

MARAMA, October 2005.). 

In brief, a number of meteorological processes affect local ozone levels within the 

Ozone Transport Region (OTR). Transport within the OTR can be divided into three 

principle components: ground level transport at the surface, transport by the nocturnal low 

level jet, and transport aloft. All three modes of transport depend on the location of the high 

pressure system. Ground level transport is the result of interaction between the synoptic flow 

and local effects, such as the sea breeze and the Appalachian lee side trough (See Factor 7 

next). Transport within the OTR can occur by the nocturnal low level jet that forms late at 

night or in the very early morning hours. This phenomenon is a result of the differential 

heating of the air between the Appalachian Mountains and the Atlantic Ocean. It has been 

observed from Georgia to Maine. The nocturnal low level jet can transport ozone that formed 

within the OTR or was transported into the OTR from outside the region. Transport aloft is 

dominated by the anti-cyclonic flow around a high pressure system, which can lead to 

transport of an ozone reservoir, created by emissions in areas that lie outside the OTR, into 

the OTR. Local emissions within the OTR add to the polluted air mixing down from above 

that arrived from more distant locations. A number of modeling studies indicate that 

pollution sources in the Ohio River Valley and the Southeast significantly contribute to 

ozone nonattainment problems in various portions of the OTR. In fact, meteorology and its 

impact on ozone and ozone precursor transport, and its impact on the formation of ozone in 
15 

the atmosphere, make this a main factor that sets ozone part from other criteria pollutants. 

Delaware believes that the meteorology factor strongly supports the establishment of large 

nonattainment boundaries due its wide-range impacts. 

 

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

The geography-topography analysis looks at physical features of the land that might 

have an effect on the air shed and, therefore, on the formation, distribution and transport of 

ozone and its precursors. Within OTR, most of the land surface is coastal and relatively 

level, and presents no significant barriers for ozone/precursor transport. The Appalachian 

Mountain seems to present a barrier for ozone/precursor transport from the mid-Atlantic 

region to the northeast region. However, a study by MARAMA (“A Guide to Mid-Atlantic 

Regional Air Quality,” October 2005.) points out that the pollutants, like ozone and its 

precursors, can make its way over the mountain from the west and will then turn 

northeastward once it reaches the coastal plain, due to the existence of the so-called 

Appalachian Lee-Side Through. Therefore, long-range transport and contribution does not 

seem to be significantly blocked or hindered by the Appalachian Mountain. In fact, the 

effect of the Appalachian Lee-Side Through, which helps to channel a more concentrated 

ozone plume and contribute to the formation of nocturnal low level jets, is the engine of rapid 

nighttime transport (See Factor 6 above). 

In addition, the Appalachian Mountains act as a physical barrier confining, to some 

degree, pollution to the coastal plain. They also induce local effects such as mountain and 

valley breezes, which, in the case of down-slope winds, can raise surface temperatures, 

thereby enhancing photo-chemical reactivity. Therefore, the Appalachian Mountains may be 

a factor enhancing the formation and transport of ozone to and within the OTR. 

8. Jurisdictional boundaries (e.g., counties, air districts, existing nonattainment 

areas, reservations, metropolitan planning organizations (MPOs)) 

 Delaware believes that this is an important factor to be considered in the designation 

process because the jurisdictional boundary is a major drawback of the CBSA/CSA -based 

nonattainment designation. The jurisdictional boundary limits the authority of a 

nonattainment area (a county or state within CBSA/CSA) to address upwind impacts on its 

nonattainment problems. Although Sections 110 and 126 of the Clean Air Act provide states 

an option to petition to EPA for controls on upwind emission sources, previous experiences 

have shown that this option is resource-intensive, extremely time-consuming, and practically 

very difficult to achieve actual results in downwind air quality improvement. 

 Discussions in the previous sections (such as Factor 1, air quality, Factor 2, emission 

data, Factor 3, population and urbanization, Factor 5, Growth) have indicated the necessity of 

designating ozone NAA boundaries beyond jurisdictional boundaries. Additional discussions 

are also provided in the following section. 
16 

9. Level of control of emission sources 

This factor is very important in nonattainment area designation and must be 

considered with the ozone/precursor transport. The key point is that if the nonattainment 

areas are not defined large and comprehensive enough, many upwind contributing 

counties/areas will not implement necessary control measures over emission sources within 

their boundaries. As a result, the pervasive transport impacts to downwind nonattainment 

areas will not be solved in a timely and cost-effective manner. 

The EPA indicates that this factor looks at the levels of controls of emission sources 

to assess whether to include additional nearby areas outside the metropolitan area as part of 

the designated nonattainment area. This approach, if and only if implemented properly, will 

be appropriate and effective in addressing transport and contribution issues because it will 

strongly support the establishment of a large nonattainment area. For the pollutant ozone 

and its precursors, the term “nearby” must be interpreted not only by geographical locations 

but also by transport and contribution scales. For example, Delaware has met reasonable 

available control technology (RACT) requirements over all major sources of volatile organic 

compounds (VOCs) and nitrogen oxides (NOx). Delaware has also adopted rules that reduce 

emissions from diesel generators, and distributed generation sources. Delaware’s mobile 

source emissions must conform to stringent emission budgets. Delaware’s power plants are 

subject to unit specific requirements that go beyond RACT. All these control levels are 

significantly greater than the levels of controls in many upwind States or areas, although 

extensive analyses have demonstrated that those states and area have contributed, are still 

contributing, and will continue to contribute significantly to Delaware’s ozone nonattainment 

problem. A proper solution of this problem is to include those upwind states and areas as 

“nearby” areas and thus as a part of the large nonattainment area, so that they will be subject 

to the same levels of controls over their major emission sources. 

For example, Delaware modeling study has shown that upwind NOx reductions 

similar in magnitude to the reductions achieved by the NOx SIP Call are needed for 

Delaware to attain the new 0.075 ppm ozone NAAQS. The data in Table 11 below shows 

that the NOx SIP call got about 140,050 tons/year of NOx reduction from power plants in the 

states that impact Delaware (i.e., difference between 2003-2007 actual emissions). If the 

power plants in these upwind states could be subject to the same levels of controls as the 

levels for the power plants in Delaware, NOx emissions in those states would be reduced by 

about 91,280 tons/year (at Phase I level) and about 108,350 tons/year (at Phase II level) tons 

from current NOx SIP Call levels (i.e., the multi-P 2007 actual emission levels). Those NOx 

reductions are so significant, although just from one major point-source subsector. The 

importance of implementing the same control levels over a large region becomes so clear. 

Table 11. NOx Emission Reductions from Upwind Power Plants* 
17 

State

2003 

Actual 

O.S. NOx 

Mass

2007 

Actual 

O.S. NOx 

Mass

CAIR 

O.S. 

2009-

2014 State 

Allocation

CAIR 

O.S. 2015 

and 

Beyond 

State 

Allocation

Estimated 

O.S. NOx 

With Phase 

I MultiP/No 

Backsliding

Estimated 

O.S. With 

NOx Phase 

II MultiP/No 

Backsliding

DE 3755 4074 2226 1855 2074 1742 

MD 18048 14907 12834 10695 7875 7033 

MI 46531 36252 28971 24142 22785 19507 

NC 48965 24167 28392 23660 17219 15320 

NJ 8152 5004 6654 5545 3116 2858 

NY 24109 16691 20632 17193 13510 12296 

OH 129209 55373 45664 39945 32242 28734 

PA 46057 52073 42171 35143 29311 26392 

VA 24895 17110 15994 13328 9472 8169 

WV 59465 26682 26859 26525 17300 16108 

 

Total 409187 252333 230397 198031 154904 138160 

 

*Note: Data are obtained from Delaware Multi-Pollutant Regulation 1146 Analysis. 

These reductions are similar in magnitude to those of the NOx SIP Call. These 

reductions, plus reductions from CAA requirements like transportation conformity and 

RACT on all major sources in these upwind states, are necessary to bring Delaware and other 

OTR non-attainment areas into attainment. Creating a large nonattainment area that includes 

the 16 states in Delaware’s recommendation would require all these upwind states to comply 

with requirements similar to Delaware (i.e., the CAA nonattainment requirements). 

Conversely, if this large nonattainment area cannot be defined in the upcoming designation 

process, many upwind contributing counties/areas will not implement necessary, costeffective control measures over emission sources within their boundaries. As a result, the 

pervasive transport impacts to downwind nonattainment areas will not be solved in a timely 

and cost-effective manner. 

The EPA also implemented or plans to implement more stringent national limits for 

vehicle emissions and fuel standards. The regional NOx controls, however, have been so far 

focused on EGU (electric generating units) emissions, which constitute only a portion of the 

whole emission inventory. The national on-road mobile controls, though proved to be 

efficient and cost-effective, also cover a portion of the emission inventory. Table 12 

provides proportional estimates of the emission inventory in the east half of the country. 

Table 12. Proportional Estimates of Emission Inventory* 

Midwest Region (Including IL, MI, ND, IN, MN, OH, IA, MO, SD, KS, NE, WI) 

EGU section: 25% 

Non-EGU section: 20% 

Non-Point section: 10% 
18 

Non-road section: 20% 

On-road section: 25% 

Southeast (Including AL, KY, SC, AR, LA, TN, DC, MS, VA, FL, NC, WV, GA) 

EGU section: 20% 

Non-EGU section: 20% 

Non-Point section: 10% 

Non-road section: 30% 

On-road section: 20% 

Northeast (Including CT, MA, PA, DE, NH, RI, ME, NJ, VT, MD, NY) 

EGU section: 15% 

Non-EGU section: 15% 

Non-Point section: 15% 

Non-road section: 25% 

On-road section: 30% 

Midwest + Southeast + Northeast: 

 Total NOx: Approximately ~8,000,000 Ton/Year 

EGU section: 20% 

Non-EGU section: 20% 

Non-Point section: 10% 

Non-road section: 25% 

On-road section: 25% 

 

*Note: Emission percentages are estimated from a 2020 emission analysis, presented by Marc 

Houyoux, OAQPS, US EPA, dated 04/27/2010. The percent numbers are further rounded to 5%-

intervals for simplification and demonstration purposes. 

From Table 12, it can be seen that the EGU emissions represent about 20% of the 

total emission inventory and the on-road vehicles represent about 25% of the total emission 

inventory. If a large NAA boundary could be established, as Delaware recommends, 

implementation of comprehensive controls in other emission sections under the CAA in the 

upwind states will help addressing the remaining 55% of emission sources. For example, 

there are many RACT sources remaining uncontrolled in the eastern US in all previously 

classified “attainment counties.” If all those sources could be controlled with the costeffective RACTs, the regional baseline of VOC and NOx emissions could be lowered 

significantly. The collective result from RACT controls in a large NAA would be another 

effective “regional” SIP Call. 

The analysis of this factor (level of emission controls) has clearly shown an 

inconsistency in control levels over the same emission sources between the CBSA/CSAbased non-attainment areas and attainment areas. The analysis again supports Delaware’s 

large NAA recommendation, but not the traditional CMSA/CSA based designation. 
Attachment 3