Air Quality

Air quality can affect park vistas, vegetation, water resources, wildlife, and overall ecosystems. Air quality is difficult to manage at the park level; influencing factors may come from hundreds of miles away.

Although air quality is not actively monitored at the park, the NPS Air Resources Division (ARD) uses data from the surrounding area to understand air quality trends and conditions for Curecanti National Recreation Area. Understanding air quality within and outside a park assists staff with planning decisions that could improve or stabilize air resources.

Clean Air Act

The Clean Air Act gives special air quality and visibility protection to national parks larger than 6,000 acres and national wilderness areas larger than 5,000 acres that were in existence when it was amended in 1977. These areas are "Class I" areas.

Curecanti National Recreation Area is a designated Class II area, which is an area that may receive more manmade air pollution than Class I areas. The adjacent Black Canyon of the Gunnison National Park, West Elk Wilderness to the north, and Weminuche Wilderness managed by the U.S. Forest Service to the south are Class I areas.

Air Quality Indicators

Air pollution can reduce visibility, increase ozone levels, and cause excess atmospheric deposition.

Visibility

The viewshed of Curecanti enhances recreation and offers opportunities to view expansive western landscapes. They are a fundamental resource of the park. Threats to scenic views come from changes in weather, light pollution, low flying aircraft, urban development, air quality, and increased fire activity. Dust storms have been an issue in the past.

Haze, which reduces visibility, is caused by tiny particles in the air. These particles can be a variety of different elements or compounds, some of which affect human health. Visibility is fair at Curecanti. The overall trend in visibility has remained relatively unchanged for the past decade. Visibility ranges from 95 to 196 miles (153 to 315 km). Without the effects of pollution, visual range could be up to 208 miles (196 to 335 km).

Ozone/Human Health

Ozone is harmful to both park ecosystems and human health. Ground-level ozone is formed when pollutants such as nitrogen oxides and volatile organic compounds react in the presence of sunlight. Coyote willow (Salix exigua) and quaking aspen (Populus tremuloides) are both park species at risk of ozone effects.

When humans breathe ground-level ozone from air pollutants, it can irritate the respiratory system and reduce lung function. Ground-level ozone concentrations for vegetation health and human health are both fair at Curecanti National Recreation Area.

Atmospheric Deposition

Airborne pollutants can be deposited in the park by wet (rain or snow) and dry (dust, particles, gas) deposition. The NPS ARD monitors nitrogen and sulfur deposition; either of these compounds in excess can be problematic for ecosystem health. High-elevation ecosystems can be more sensitive to nitrogen deposition. Excess nitrogen can over fertilize soil, affect the cycling of other nutrients, and alter plant communities. Nitrogen and sulfur can also accumulate in rivers, streams, lakes, and other bodies of water. This contributes to acidification and negative impacts to aquatic life and adjacent ecosystems.

Ecosystems naturally can buffer some pollution, but they do have a threshold called the critical load. Critical load is the amount of pollution above which harmful changes in sensitive ecosystems occur.

Wet nitrogen deposition levels at Curecanti are poor. Some of the most sensitive ecosystem components, like some herbaceous species, may be experiencing harm from deposition levels. Despite low measurements, sulfur deposition levels are fair due to the park’s highly sensitive ecosystems to acidification.

Monitoring & Data Collection

In the past, the Northern Colorado Plateau Network (NCPN) compiled information from the NPS ARD and other cooperating programs. Air quality monitoring reports were published for parks within the network.

Currently, park managers and the public can view data on air quality indicators of ozone, visibility, and deposition on the Air Resources Division website. Information is available on more than 350 NPS units. Some parameter data goes back to 1989; others start in the early 2000s.