Protecting Clean Air in National Parks and Wilderness Areas

November 2, 2016

Protecting Clean Air in National Parks and Wilderness Areas

In 1977, major amendments to the Clean Air Act (CAA)

included provisions for the prevention of significant

deterioration (PSD) of air quality. The PSD provisions were

enacted for several purposes, including

to preserve, protect, and enhance the air quality in

national parks, national wilderness areas, national

monuments, national seashores, and other areas of

special national or regional natural, recreational,

scenic, or historic value; [and]

to insure that economic growth will occur in a

manner consistent with the preservation of existing

clean air resources....

Two significant aspects of the PSD provisions relate to

federal lands and federal land managers: the classification

of areas for air quality protection and management, and the

role of federal land managers in maintaining and improving

air quality under the CAA.

Classification of Areas

The PSD provisions establish classifications of air quality

(42 U.S.C. §7472). Class I areas are those with the highest

air quality and whose air quality is most stringently

protected. Class II includes all other areas, unless they are

designated “nonattainment” for one of the U.S.

Environmental Protection Agency’s (EPA’s) National

Ambient Air Quality Standards. The CAA provides that in

areas designated as Class I, the “maximum allowable

increase” in the concentration of particulate matter (5 µg/m3

annually, or a maximum of 10 µg/m3 during a 24-hour

period) may be only about one-fourth the allowable

increase in a Class II area (19 µg/m3 and 37 µg/m3,

respectively). The allowable increase of sulfur dioxide

concentrations in Class I areas is even more strictly

controlled as compared to the allowable increase in a Class

II area.

As specified in the statute, the Class I areas consist of

certain federally protected sites that were in existence on

the amendments’ date of enactment, August 7, 1977. The

areas that were designated as Class I included national

parks larger than 6,000 acres, national wilderness areas

larger than 5,000 acres, and certain other sites. Altogether,

48 National Park System units (managed by the National

Park Service, in the Department of the Interior);

21 wilderness areas in the National Wildlife Refuge System

(managed by the Fish and Wildlife Service, in the

Department of the Interior); 86 wilderness areas in the

National Forest System (managed by the U.S. Forest

Service, in the Department of Agriculture); and

1 international park (managed by a U.S.-Canadian

commission) were designated as Class I areas—156 sites

in all (see Figure 1).

The PSD provisions (42 U.S.C. §7474) established a

process by which the states can change area designations.

However, the initial Class I areas cannot be redesignated.

Figure 1. Mandatory Class I National Parks and Wilderness Areas Under the Clean Air Act

Source: CRS, using data from EPA, “Visibility—Regional Haze Program,” at https://www.epa.gov/visibility/visibility-regional-haze-program.

Note: Territories other than the U.S. Virgin Islands are not shown because they contain no Class I areas.

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Protecting Clean Air in National Parks and Wilderness Areas

For new protected areas established after the enactment of

the 1977 CAA amendments, the act does not provide for the

areas’ automatic designation as Class I. Rather, new

federally protected areas can only be redesignated as Class I

by the state, under the process established in the CAA. The

CAA does not specify which agency or official within the

state may redesignate an area as Class I; the legislation

merely states in Section 164(a) that “a State may

redesignate such areas as it deems appropriate as Class I

areas.” The section requires public hearings and an analysis

of the “health, environmental, economic, social, and energy

effects of the proposed redesignation,” which must be made

available for public inspection prior to redesignation. To

date, no state has redesignated as Class I any national park

or wilderness area established after August 7, 1977.

To date, no state has redesignated as Class I any

national park or wilderness area established after

August 7, 1977.

In addition to Class I and Class II, the statute envisioned the

possibility of redesignating some areas to a less stringently

protected Class III, but no state has done so.

Role of Federal Land Managers

Under land management laws such as the National Park

System Organic Act and the Wilderness Act, federal land

managers (FLMs) are responsible for protecting the air

quality for the lands they administer. The CAA also

provides FLMs with means and opportunities to protect air

quality for the lands they manage.

An FLM is defined in the CAA as the Secretary of the

department with authority over the lands in question. In

practice, the Secretary has delegated this authority to an air

quality branch or to the official charged with direct

responsibility for the land in question. The CAA gives the

FLMs certain roles and responsibilities in regulatory

decisions that might affect air quality in federally protected

areas.

All CAA regulatory decisions require public notice of the

proposed actions and opportunity for comment. Many CAA

provisions also require consultation with FLMs. For

example, EPA or the states must consult with FLMs of

Class I areas regarding permits for new major sources of air

pollution that might degrade the air quality of the areas.

FLMs would have the opportunity to demonstrate that the

increased pollution would harm the air quality, such as by

reducing visibility.

The FLM’s role is an advisory one. As noted in a 2010

interagency guidance document known as the FLAG

Report, “Although the FLMs have an ‘affirmative

responsibility’ to protect AQRVs [air quality-related

values], they have no permitting authority under the CAA,

and they have no authority under the CAA to establish air

quality-related rules or standards. The FLM role within the

regulatory context consists of considering whether

emissions from a new source, or emission increases from a

modified source, may have an adverse impact on AQRVs

and providing comments to permitting authorities (States or

EPA).” (See http://www.nature.nps.gov/air/Pubs/pdf/flag/

FLAG_2010.pdf.)

The CAA does not specify how close a new major source

must be to a Class I area to trigger the consultation

requirement. The FLAG Report states, “Generally, the

permitting authority should notify the FLM of all new or

modified major facilities proposing to locate within 100 km

(62 miles) of a Class I area. In addition, the permitting

authority should notify the FLM of ‘very large sources’

with the potential to affect Class I areas proposing to locate

at distances greater than 100 km.”

The FLM’s role in CAA decisions is most explicit for, but

is not limited to, Class I areas. FLMs also can be involved

in CAA decisions that affect Class II areas, particularly

when scenic vistas are a significant value for the areas.

According to the FLAG Report, similar criteria apply to

Class II areas: “Under the Clean Air Act, the FLM formal

‘affirmative responsibility’ role in the permitting process is

limited to the extent a proposed new or modified source

may affect AQRVs in a Class I area.... Nevertheless, the

FLMs are also concerned about resources in Class II parks

and wilderness areas because they have other mandates to

protect those areas as well. The information and procedures

outlined in this document are generally applicable to

evaluating the effect of new or modified sources on the

AQRVs in both Class I and Class II areas.”

Besides requiring that major emitting facilities obtain preconstruction PSD permits, the CAA sets a national goal of

preventing future impairment of visibility in Class I areas

and remedying existing impairment. The states are to

develop implementation plans (SIPs) demonstrating

reasonable progress toward this regional haze goal at 10year intervals. On May 4, 2016, EPA proposed revisions to

its Regional Haze Rule (81 Fed. Reg. 26942) that would

strengthen the role of FLMs in the development of these

SIPs by requiring states to consult with FLMs earlier in the

process of developing the plans.

Additionally, FLMs fulfill their responsibilities for

protection of AQRVs by participating in EPA’s

development of air quality regulations. For example, FLMs

may participate in scoping meetings and other public

forums as regulations are being developed. They also may

support scientific research on the sources and effects of air

pollution on federal lands and resources—for example, by

conducting projects to monitor AQRVs on federal lands and

by participating in interagency research committees.

For Additional Reading

For additional information, see CRS Report RL30853,

Clean Air Act: A Summary of the Act and Its Major

Requirements, by James E. McCarthy and Claudia

Copeland.

James E. McCarthy, Specialist in Environmental Policy

Laura B. Comay, Analyst in Natural Resources Policy

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IF10496

Protecting Clean Air in National Parks and Wilderness Areas

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