Air Quality

On clear days, park visitors can see for miles at various overlooks.

NPS Photo

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 be coming from hundreds of miles away.

Although air quality is not actively monitored at the park, the NPS Air Resources Division utilizes data from the surrounding area to understand air quality trends and conditions for Black Canyon of the Gunnison National Park. 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.

Black Canyon of the Gunnison National Park is a designated Class I area. Air quality standards are stricter in these parks than in other network parks. The West Elk Wilderness to the north and Weminuche Wilderness to the south are also Class I areas managed by the U.S. Forest Service.

 

Threats to views can come from weather, light pollution, air quality, and increased fire activity.

NPS Photo

Air Quality Indicators

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

Visibility

Spectacular views are one of the fundamental resources of the park. Threats to these views come from changes in weather, light pollution, urban development, air quality, and increased fire activity.

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. The overall trend in visibility has improved at Black Canyon since the 1990s and continues to be good. Visibility ranges from 96 to 187 miles (154 to 301 km) but could be up to 200 miles (322 km) without the effects of pollution.

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. Ponderosa pine (Pinus ponderosa) 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 Black Canyon of the Gunnison National Park.

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, such as the canyon rim of Black Canyon and surrounding ridges, 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 Black Canyon are fair and some of the most sensitive ecosystem components may be experiencing harm. Sulfur deposition levels are considered good as of 2022.

 

Monitoring & Data Collection

In the past, the Northern Colorado Plateau Network (NCPN) compiled information from the NPS Air Resources Division 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. Information is available on more than 350 NPS units. Some parameter data for Black Canyon of the Gunnison National Park goes back to 1989; others start in the early 2000s.

 

Visibility on Haziest and Clearest Days from 2013-2022 at Black Canyon

NPS Air Resources Division