Zion National Park AQRV's
Most surface waters in Zion NP are likely to be well-buffered and, as a result, insensitive to acidic atmospheric deposition because of an abundance of base cations in underlying park soils and rocks.
While there have been no systematic studies, there is currently no information indicating that wildlife in Zion NP are being affected by air pollutants.
Dark night skies are considered an important air quality related value at Zion NP, possessing value as a cultural, scenic, natural, and scientific resource. Air pollution and poor quality outdoor lighting degrade night skies, lessening a viewer's ability to see stars and other astronomical objects, and altering the nocturnal scene. Use of high quality lighting that produces very little scattered light can greatly improve the night sky. Reduction of haze from air pollution can also improve the night sky.
Soils in Zion NP may be sensitive to atmospheric deposition of nitrogen compounds. In some areas of the country, elevated nitrogen deposition has been shown to alter soil nutrient cycling. Studies are underway in Canyonlands NP to investigate nitrogen effects on soil dynamics, exotic plant invasiveness, and biological soil crusts. Results from these studies may be applicable to Zion NP.
Several plant species that occur in Zion NP are known to be sensitive to ozone, including Populus tremuloides (quaking aspen), Symphoricarpos oreophilus (snowberry), and Pinus ponderosa (ponderosa pine). In 1999, the National Park Service Air Resources Division surveyed vegetation in Zion NP and found probable ozone injury on several species, including Symphoricarpos oreophilus. Surveys in nearby Cedar Breaks NM and Bryce Canyon NP also found symptoms of ozone injury on vegetation.
Vegetation in Zion NP may also be sensitive to nitrogen deposition. In some parts of the country, excess nitrogen deposition has resulted in changes in species composition and abundance; native plants adapted to nitrogen-poor conditions have been replaced by invasive and exotic species that are better able to utilize nitrogen.
- Ozone Sensitive Plant Species Listed by Park
- Ozone Sensitive Plant Species on NPS and U.S. FWS Lands
- Ozone Bioindicators on NPS and U.S. FWS Lands
Visibility is a sensitive AQRV at Zion NP. The data record at Zion NP (from the aerosol sampler) is insufficient to analyze temporal trends. However, an analysis of 1990-1999 data from the Colorado Plateau region indicates that visibility in other parks is improving somewhat on the clearest days, but degrading on the haziest days.