Importance/Issues

Park resources affected by air quality include scenery and vistas, vegetation, water, and wildlife. Both the Clean Air Act and the NPS Organic Act protect air resources in national parks, with particular emphasis on parks containing designated wilderness. Chiricahua NM and Saguaro NM contain wilderness areas that are designated Class 1 airsheds: the highest standard for air quality.

Parks Monitored

Chiricahua NM, Fort Bowie NHS, Gila Cliff Dwellings NM, Organ Pipe Cactus NM, Saguaro NP, Tonto NM

Monitoring Objectives

The NPS monitors air quality parameters in SODN park units in cooperation with national air quality monitoring programs. Air quality data are summarized and analyzed for conditions and trends by both the NPS Air Resources Division and other national programs, and the SODN will not replicate these analyses. Instead, the network will compile the data summaries created by these groups, report on them, and analyze them in conjunction with other SODN vital signs.

SODN air quality monitoring questions are:

What are the conditions and spatial and temporal trends in ozone, nitrogen deposition, sulfur deposition, and visibility-reducing pollutants in SODN park units?

How do ozone, nitrogen deposition, sulfur deposition, and visibility-reducing pollutants vary with associated vital signs (e.g., vegetation community composition, exotic plant status, climate)?

Potential Measures

Diurnal concentration (ppb) of ozone.

Annual concentration (mg/L) and deposition (kg/ha) of sulfate, nitrate, ammonium.

Mean daily light extinction (%) and aerosol composition (% by class).

Management Applications

Because emission of harmful air pollutants occurs over broad spatial scales, park managers have little direct control over the atmospheric conditions of the parks they manage. However, documenting the status and trends of air quality constituents can provide managers with regulatory and policy tools to influence off-site emitters and indirectly stabilize or improve park air resources. Accounting for the potential effects of air quality may also help clarify the consequences of stressors that park managers can directly affect.

Protocol Development Status

Protocol completed in Spring 2007; currently under revision. Annual data will be used, based on fiscal year.

Status & Trends

Determination of air quality status and trends is ongoing using current and archived data.

Project Leads

Andy Hubbard, Network Program Manager