United States Court of Appeals

FOR THE DISTRICT OF COLUMBIA CIRCUIT

Decided November 29, 2005

Reissued January 18, 2006

No. 04-1211

COMMONWEALTH OF PENNSYLVANIA,

DEPARTMENT OF ENVIRONMENTAL PROTECTION AND

STATE OF DELAWARE,

PETITIONERS

v.

ENVIRONMENTAL PROTECTION AGENCY,

RESPONDENT

AMERICAN LUNG ASSOCIATION, ET AL.,

INTERVENORS

On Petition for Review of an Order of the

Environmental Protection Agency

Richard P. Mather, Sr., Kristen M. Campfield,

Commonwealth of Pennsylvania, Department of Environmental

Protection, M. Jane Brady, Attorney General, Attorney

General’s Office of the State of Delaware, and Valerie S.

Csizmadia, Deputy Attorney General, were on the briefs for

petitioners.

Kelly A. Johnson, Acting Assistant Attorney General, U.S.
2

*Senior Circuit Judge Edwards was in regular active

service at the time of oral argument.

Department of Justice, John C. Cruden, Deputy Assistant

Attorney General, Lily N. Chinn, and Jan Tierney, U.S.

Environmental Protection Agency, were on the brief for

respondent. Eric G. Hostetler, U.S. Department of Justice,

entered an appearance. 

Before: TATEL and BROWN, Circuit Judges, and EDWARDS,

Senior Circuit Judge.

*

Opinion for the Court filed by Circuit Judge TATEL.

TATEL, Circuit Judge: Pennsylvania and Delaware each

challenges Environmental Protection Agency boundaries for

areas not in compliance with Clean Air Act ozone pollution

standards. Finding EPA’s boundaries neither arbitrary nor

capricious, we deny the petitions for review.

I.

Title I of the Clean Air Act (CAA) charges EPA with

formulating National Ambient Air Quality Standards (NAAQS).

42 U.S.C. §§ 7408-09. NAAQS set maximum permissible

concentrations of certain specified pollutants in the ambient air.

Id. In 1997, EPA established an 8-hour standard for ozone that

required areas to stay below 0.08 parts per million of ozone

concentration averaged over 8 hours. 40 C.F.R. § 50.10. 

According to CAA procedures, once EPA promulgates a

NAAQS, each State must submit proposed designations for all

areas within its borders. States designate areas as “attainment”

or “nonattainment” depending on the level of compliance or,

absent adequate information, as “unclassifiable.” 42 U.S.C.

§ 7407(d)(1). After receiving state recommendations, EPA
3

promulgates final designations. The statute grants EPA the

following authority to modify state suggestions:

[T]he Administrator may make such modifications as

the Administrator deems necessary to the designations

of the areas (or portions thereof) submitted [by the

States] (including to the boundaries of such areas or

portions thereof). Whenever the Administrator

intends to make a modification, the Administrator

shall notify the State and provide such State with an

opportunity to demonstrate why any proposed

modification is inappropriate.

42 U.S.C. § 7407(d)(1)(B)(ii). 

The CAA establishes either the Metropolitan Statistical

Area (MSA) or the Consolidated Metropolitan Statistical Area

(C/MSA) as the presumptive boundary for nonattainment areas

classified as serious, severe, or extreme. 42 U.S.C. §

7407(d)(4)(A)(iv). The CAA is silent, however, with respect to

boundary setting for areas designated as “moderate”—such as

the areas at issue in this case. See Air Quality Designations and

Classifications for the 8-Hour Ozone National Ambient Air

Quality Standards; Early Action Compact Areas with Deferred

Effective Dates, 69 Fed. Reg. 23,858, 23,909 (Apr. 30, 2004) (to

be codified at 40 C.F.R. pt. 81) (“Designation Rule”)

(designating Cecil County, Maryland as “moderate”); id. at

23,921 (designating Ocean County, New Jersey as “moderate”).

As a result, EPA promulgated a policy to guide States through

the designation process for all areas within their boundaries. See

8-Hour Ozone NAAQS Guidance on Nonattainment

Designations (Mar. 28, 2000) (“Designation Guidance”).

Mirroring the CAA, the Designation Guidance sets the MSA or

C/MSA as the presumptive boundary for all nonattainment areas

regardless of the severity of their nonattainment status. Id. at 3.
4

For areas designated nonattainment for the 1-hour ozone

standard (the standard in place before the 8-hour NAAQS), the

Designation Guidance sets the larger of the C/MSA or the 1-

hour nonattainment area as the presumptive boundary. Id. at 6.

Under the Designation Guidance, States wishing to modify

presumptive boundaries must undertake a detailed analysis of

eleven specified factors—including population density, location

of emission sources, traffic and commuting patterns,

meteorology, and geography. See id. at 4 (listing the eleven

factors); see also 42 U.S.C. § 7407(d)(4)(A)(v) (enumerating six

similar factors the Administrator should consider when asked to

amend the presumptive boundaries for serious, severe, and

extreme areas).

 

This case concerns EPA’s placement of two counties:

Ocean County, New Jersey and Cecil County, Maryland. Ocean

County is in the New York-Northern New Jersey-Long Island 1-

hour nonattainment area, its presumptive location for the 8-hour

NAAQS. See Letter from Jane M. Kenny, Regional

Administrator, EPA Region II, to James E. McGreevey,

Governor of New Jersey (Dec. 3, 2003); see also Designation

Guidance 6 (designating 1-hour nonattainment area boundaries

as presumptive locations for nonattaining counties). Cecil

County is in the Philadelphia-Wilmington-Atlantic City

nonattainment area, its presumptive location. See Letter from

Donald D. Welsh, Regional Administrator, EPA Region III, to

Robert L. Ehrlich Jr., Governor, State of Maryland (Dec. 3,

2003); see also Designation Guidance 6. In a letter to EPA,

New Jersey asked the Agency to transfer Ocean County to the

Philadelphia nonattainment area and Cecil County to the

Baltimore-Washington-Northern Virginia nonattainment area.

According to New Jersey, because Ocean County lies downwind

from Philadelphia, the Philadelphia nonattainment area affects

that county’s air quality far more than does the New York

nonattainment area. Similarly, New Jersey argued that because
5

Cecil County lies downwind of Baltimore, the Baltimore

nonattainment area affects that county’s air quality more than

does the Philadelphia nonattainment area. Id. Connecticut and

New York supported New Jersey’s request. Maryland

disagreed, recommending that Cecil County remain in the

Philadelphia area. Pennsylvania said nothing about Cecil

County’s placement, but recommended that Ocean County

remain in the New York area, arguing that Ocean County

emissions affect New York’s air quality more than

Philadelphia’s. Taking an entirely different approach, Delaware

urged EPA to create one regional nonattainment area spanning

from Northern Virginia to Maine. No State submitted the

required eleven-factor analysis.

EPA declined to transfer either county, citing Ocean

County’s location within the New York nonattainment area and

Maryland’s recommendation that Cecil County remain in the

Philadelphia nonattainment area. In follow-up letters to EPA,

New Jersey, New York, Connecticut, Delaware, and

Pennsylvania each reiterated their recommendations and

supplied additional information. Only New Jersey submitted the

required eleven-factor analysis, but only in support of its

recommendation to transfer Ocean County to the Philadelphia

nonattainment area. Maryland, which supported keeping Cecil

County in its presumptive location, filed no new information. 

 In a Federal Register announcement issued on April 30,

2004, EPA designated and established the geographic

boundaries for attainment, nonattainment, or unclassifiable areas

throughout the nation. See Designation Rule, 69 Fed. Reg. at

23,877-23,951. The final rule included both Ocean and Cecil

counties in the Philadelphia nonattainment area. Id. at 23,921,

23,909. In other words, EPA moved Ocean County from its

presumptive location in the New York area to the Philadelphia

area (as New Jersey had requested), but left Cecil County in its
6

presumptive location in the Philadelphia area (as Maryland had

requested). 

Petitioners, Pennsylvania’s Department of Environmental

Protection and Delaware, challenge EPA’s Designation Rule,

arguing that the Agency’s inconsistent consideration of

downwind effects renders the Ocean and Cecil County

designations arbitrary and capricious. In addition, Delaware

reiterates its view that EPA should have established a much

larger nonattainment area encompassing the entire northeast

corridor. In reviewing these claims, we set aside EPA’s air

quality designations only if we find them “arbitrary, capricious,

an abuse of discretion, or otherwise not in accordance with law.”

5 U.S.C. § 706(2)(A). Under this standard, we will not

substitute our judgment for the agency’s, especially where the

challenged decision implicates substantial agency expertise.

Huls America Inc. v. Browner, 83 F.3d 445, 452 (D.C. Cir.

1996); see also Appalachian Power Co. v. EPA, 135 F.3d 791,

801-02 (D.C. Cir. 1998) (“Our analysis is guided by the

deference traditionally given to agency expertise, particularly

when dealing with a statutory scheme as unwieldy and sciencedriven as the Clean Air Act.”). 

II.

We begin with EPA’s decision to place both Ocean and

Cecil counties in the Philadelphia nonattainment area.

According to Pennsylvania and Delaware, these placements are

contradictory. Although both areas are affected by downwind

pollution (Ocean County by Philadelphia and Cecil County by

Baltimore), EPA assigned Ocean County on the basis of its

vulnerability to Philadelphia’s downwind pollution, but left

Cecil County in its presumptive Philadelphia location

notwithstanding Baltimore’s downwind effects. The two States

also contend that EPA simply deferred to Maryland’s

recommendation that Cecil County remain in its presumptive
7

location, thus abdicating its statutory responsibility to make final

nonattainment decisions.

EPA defends its action on two grounds. First, relying on

the primary emphasis it gives to “the recommendations made by

States for the areas within their borders,” Resp’t’s Br. 13, it

points out that New Jersey supported transferring Ocean County

to the Philadelphia nonattainment area while Maryland opposed

transferring Cecil County to Baltimore. As EPA observes, the

CAA gives great deference to governors’ recommendations for

areas within their states, providing only that EPA “may” make

any modifications it “deems necessary.” 42 U.S.C. §

7407(d)(1)(B)(ii) (emphasis added). Second, EPA relies on

New Jersey’s eleven-factor analysis, which provides evidence,

supported by EPA’s own modeling of wind trajectories, that

“New York state contributes very little to Ocean County’s ozone

violations, particularly when compared to Pennsylvania.”

Resp’t’s Br. 16. As to Cecil County, EPA points out that

contrary to its Designation Guidance, no State submitted an

eleven-factor analysis supporting the county’s transfer to the

Baltimore area. 

Given our highly deferential standard of review, we see no

basis for upsetting EPA’s designations. In the Designation

Guidance—which neither Pennsylvania nor Delaware

challenges—EPA says quite clearly it will exercise its discretion

to modify home state recommendations only when it receives

evidence on eleven relevant factors which, together with data

collected by the Agency, demonstrate that the presumptive

boundary—the 1-hour nonattainment area in this case—is

inappropriate. See Designation Guidance 4, 6. In assigning

Ocean and Cecil counties to the Philadelphia nonattainment

area, EPA adhered to this policy. As to Cecil County, since no

one provided an eleven-factor analysis to overcome the county’s

presumptive placement, EPA deferred to the home state
8

(Maryland) recommendation, and placed the county within the

Philadelphia nonattainment area. As to Ocean County, not only

did the home state (New Jersey) recommend placing the county

in the Philadelphia nonattainment area rather than the New York

area, but the State provided a supporting eleven-factor analysis.

To be sure, the two placement decisions appear inconsistent

with respect to EPA’s consideration of downwind effects.

Under EPA’s own standards, however, the decisions are

perfectly consistent: In both cases, EPA deferred to home state

recommendations and adhered to the Designation Guidance

requirement that those seeking to amend presumptive

boundaries must submit an eleven-factor analysis. We will

therefore deny the petitions for review on this issue.

III.

This brings us to Delaware’s challenge to EPA’s placement

of nonattaining counties in locally based C/MSAs or 1-hour

nonattainment areas rather than in the “broader, contiguous,

interstate nonattainment area” proposed by Delaware. Pet’rs’

Br. 32. Citing “undisputed evidence that ground level ozone is

a regional problem in the Mid-Atlantic, with transport being a

significant issue of concern,” Delaware argues that EPA has

impaired CAA goals by refusing to create one large

nonattainment area consisting of all States whose contributions

to pollutants affect each other’s ability to reach attainment. Id.

at 28. 

The CAA refers to the designation of nonattaining counties

and “nearby area[s]” that contribute to exceedances. 42 U.S.C.

§ 7407(d)(1)(A)(i). EPA interprets “nearby” to require locallybased nonattainment areas, explaining that “Congress has

established a different mechanism to deal with . . . [the] longrange ozone transport problem.” Resp’t’s Br. 27. Offering a

different interpretation of the CAA, Delaware contends that
9

since all counties from Virginia to Maine are nonattainment

areas, all are “nearby” and that nothing in the statute prevents

placing them in one contiguous area. While this construction of

“nearby” may well be sensible, Chevron requires that we defer

to the agency’s reasonable interpretation of the term, and

Delaware has given us no reason to think that EPA’s

interpretation is unreasonable. Chevron U.S.A. Inc. v. Natural

Res. Def. Council, Inc., 467 U.S. 837, 843 (1984) (“[I]f the

statute is silent or ambiguous with respect to the specific issue,

the question for the court is whether the agency’s answer is

based on a permissible construction of the statute.”). 

Defending its failure to produce an eleven-factor analysis,

Delaware argues that “in practice” the Designation Guidance

promotes smaller nonattainment areas, “exactly the opposite of

what Delaware believes should be done under the CAA.” Reply

Br. 10. But Delaware has offered no evidence that “in practice”

EPA will not enlarge a nonattainment area in response to an

eleven-factor analysis. Indeed, in this case EPA did just that:

Responding to New Jersey’s eleven-factor analysis, it enlarged

the Philadelphia area to include Ocean County. 

In sum, given EPA’s broad discretion under the CAA to

determine when to modify state proposals, and given Delaware’s

failure either to produce the eleven-factor analysis or to

challenge the Designation Guidance, Delaware has offered us no

basis for questioning EPA’s rejection of its proposal to establish

a broad, interstate nonattainment area. 

IV.

The petitions for review are denied.

So ordered.