Air Resources Management

Definitions

Air quality related value (AQRV): A resource that may be adversely affected by a change in air quality. The resource may include visibility or a specific scenic, cultural, physical, biological, ecological, or recreational resource.

Adverse impact on an AQRV: An unacceptable effect that results from current, or would result from predicted, deterioration of air quality in a unit of the National Park System. A determination of unacceptable effect shall be made on a case-by-case basis for each area, taking into account existing air quality conditions. The determination should be based on a demonstration that the current or predicted deterioration of air quality will cause or contribute to a diminishment of the area's national significance, impairment of the structure and functioning of the area's ecosystem, or impairment of the quality of the visitor experience in the area.

Attainment area: A geographic area in which the quality of the air is better than the applicable national ambient air quality standards. This classification is pollutant specific.

Best management practice: A practice, or combination of practices that apply the most current means and technologies available to comply with mandatory environmental regulations and maintain a superior level of environmental performance. (DO 13 Environmental Leadership.)

Class I, II, and III areas: The area classification scheme established by Congress to facilitate implementation of the prevention of significant deterioration (see definition below) of the air quality provisions of the Clean Air Act.

Class I areas receive the highest degree of protection, with only a small amount of certain kinds of additional air pollution allowed (see Increments, below).
Mandatory Class I areas were designated by Congress and include international parks, national wilderness areas or national memorial parks larger than 5,000 acres, or national parks larger than 6,000 acres, that were in existence (or authorized) on August 7, 1977. The 1990 amendments to the Clean Air Act specified that acreage added to these areas after 1977 must also receive Class I designation. Mandatory Class I areas may not be redesignated to any other classification.

Congress initially designated all other attainment areas as Class II and allowed a moderate increase in certain air pollutants. Congress prohibited redesignation of some Class II areas exceeding 10,000 acres to the less protective Class III status. These include national monuments, national primitive areas, national preserves, national recreation areas, national wild and scenic rivers, national wildlife refuges, and national lakeshores or seashores that were in existence (or authorized) on August 7, 1977, and national parks and wilderness areas established after August 7, 1977. These areas are called Class II floor areas. (See Exhibit 1 for a list of NPS units designated as Class I or Class II floor areas.)

No Class III areas, where a large amount of new air pollution would be allowed, were designated by Congress, but a process was established for redesignating Class II areas to the more protective Class I or the less protective Class III status. Only states or Native American governing bodies have authority to redesignate these areas, except as noted above.

Criteria pollutant: A pollutant for which a national ambient air quality standard has been established (i.e., sulfur dioxide (SO₂), carbon monoxide (CO), ozone (O₃), lead (Pb), nitrogen dioxide (NO₂), particulate matter less than 10 microns in diameter (PM₁₀), and particulate matter less than 2.5 microns in diameter (PM_2.5).

Environmental leadership: Demonstrating on a personal and organizational level a commitment to comprehensive environmental compliance, the use of best management practices, the principles of sustainability and the active communication of these actions to others. (DO 13 Environmental Leadership.)

Increments: Maximum allowable increases of certain air pollutants (i.e., SO₂, NO₂, PM₁₀) in Class I, II, and III areas. Small increases are allowed in Class I areas, moderate increases are allowed in Class II areas, and large increases are allowed in Class III areas. These increments have been established by Congress or the EPA to prevent significant deterioration of air quality in attainment areas.

Major stationary source: Any source in a fixed location that emits at least 250 tons per year of any pollutant regulated under the Clean Air Act or any source from among 28 source categories that emits at least 100 tons per year of any regulated pollutant.

National Ambient Air Quality Standard (NAAQS): National standards established by the EPA under the Clean Air Act for various air pollutants to protect public health (primary NAAQS) and public welfare (secondary NAAQS). These standards are applicable nationwide and are not to be violated.

Nonattainment area: A geographic area in which the NAAQS are violated. This classification is pollutant specific.

Pollution prevention: The use of materials, processes, or practices that reduce or eliminate the quantity and/or toxicity of wastes at the source of generation or at the site of release. (DO 13 Environmental Leadership.)

Prevention of Significant Deterioration (PSD): The program established under the Clean Air Act to regulate allowable future increases in air pollution in clean air regions of the country and for the planning and management of the allocation and use of air resources.

State Implementation Plan: A plan devised by a state (or the EPA if a state fails to adopt an acceptable plan) to implement and enforce Clean Air Act requirements. Each State Implementation Plan must include provisions to attain and maintain NAAQS, to prevent significant deterioration of air quality, and to protect visibility in mandatory Class I areas.

Sustainability: Actions that promote social equity, economic viability, and ecological integrity and biodiversity, so as to meet the needs of the present, without compromising the ability of future generations to meet their own needs. (DO 13 Environmental Leadership).