- Air quality at Guadalupe Mountains National Park
- Related references
Air quality at Guadalupe Mountains National Park
Most visitors expect clean air and clear views in parks. Guadalupe Mountains National Park (NP), Texas—home to portions of the world’s most extensive and significant limestone fossil reef, and diverse biological areas from the Chihuahuan Desert to conifer forest—experiences moderately good air quality. The park is downwind of pollution from oil and gas development, power plants, and even sources in Mexico. The National Park Service works to address air pollution effects at Guadalupe Mountains NP, and in parks across the U.S., through science, policy and planning, and by doing our part.
Visitors come to Guadalupe Mountains NP to enjoy views of mountain and desert land in West Texas. Park vistas are sometimes obscured by haze, reducing how well and how far people can see. Visibility reducing haze is caused by tiny particles in the air, and these particles can also affect human health. Many of the same pollutants that ultimately fall out as nitrogen and sulfur deposition contribute to this haze. Organic compounds, soot, dust, and wood smoke reduce visibility as well. Significant improvements in park visibility on the clearest days have been documented since the 1990’s. Still, visibility in the park has not improved significantly on the haziest days, and park visibility is a long way from the Clean Air Act goal of no human caused impairment.
- Reduced visibility, at times, due to both natural and human-caused haze and fine particles of air pollution, including dust and wildfires;
- Reduction of the average natural visual range from about 175 miles (without pollution) to about 90 miles because of pollution at the park;
- Reduction of the visual range to below 55 miles on very hazy days.
Nitrogen and sulfur
Nitrogen and sulfur compounds deposited from the air may have harmful effects, on soils, lakes, ponds, and streams. Healthy ecosystems can naturally buffer a certain amount of pollution, but as nitrogen and sulfur accumulate, a threshold is passed where the ecosystem is harmed. “Critical load” is a term used to describe the amount of pollution above which harmful changes in sensitive ecosystems occur (Porter 2005). Nitrogen deposition exceeds the critical load for one or more park ecosystems (NPS ARD 2018). Additionally, ecosystems are very highly sensitive to nutrient enrichment at Guadalupe Mountains NP relative to other national parks (Sullivan et al. 2011a; Sullivan et al. 2011b).
Arid shrublands and grasslands in the park are particularly vulnerable to changes caused by nitrogen deposition. Increases in nitrogen have been found to promote the growth of invasive annual grasses and forbs (e.g., Russian thistle) at the expense of native species (Brooks 2003; Schwinning et al. 2005; Allen et al. 2009). Fires occur naturally in the northern Chihuahuan Desert (Gebow and Halvoson 2004), but invasive grasses can increase fire risk (Rao et al. 2010; Balch et al. 2013) and affect plant biodiversity. Weed density is also known to increase in post-fire environments with higher nitrogen levels in soil (Floyd-Hanna et al. 2004). Experiments in similar oak-pine forests show that nitrogen additions affect the diversity of soil microbes (Zak 2006).
Nitrogen, together with sulfur, can also acidify surface waters and soils. Given the abundance of base cations in underlying park soils and rocks, surface waters in Guadalupe Mountains NP are generally well-buffered from acidification. However, small streams with steep-sided canyon walls in the park have little ability to retain nutrients and water, offering the landscape little opportunity to buffer potentially acidic run-off (Sullivan et al. 2011c; Sullivan et al. 2011d). Some plant species are sensitive to acidification, search for acid-sensitive plant species found at Guadalupe Mountains NP.
Visit the NPS air quality conditions and trends website for park-specific nitrogen and sulfur deposition information. Guadalupe Mountains NP has been monitoring atmospheric deposition of nitrogen and sulfur since 1984. Explore air monitoring »
At ground level, ozone is harmful to human health and the environment. Ground-level ozone does not come directly from smokestacks or vehicles, but instead is formed when other pollutants, mainly nitrogen oxides and volatile organic compounds, react in the presence of sunlight.
Over the course of a growing season, ozone can damage the leaves of plants, reducing their growth rate and making them less resistant to disease and insect infestations. Some plants are more sensitive to ozone than others. There are a few ozone-sensitive plants in Guadalupe Mountains NP including Populus tremuloides (quaking aspen), Rhus trilobata (skunkbush), and Salix gooddingii (Goodding’s willow). A risk assessment that considered ozone exposure, soil moisture, and sensitive plant species concluded that plants in Guadalupe Mountains NP were at low risk of damage to plant leaves (see network report: Kohut 2004). Generally, dry conditions in the park during peak ozone concentrations are likely to limit ozone uptake by plants. However, along streams and seeps where conditions are wetter, plants may have higher ozone uptake and injury (Kohut et al. 2012). Search ozone-sensitive plant species found at Guadalupe Mountains NP.
Visit the NPS air quality conditions and trends website for park-specific ozone information.
Allen, E. B., L. E. Rao, R. J. Steers, A. Bytnerowicz, and M. E. Fenn. 2009. Impacts of atmospheric nitrogen deposition on vegetation and soils in Joshua Tree National Park. Pages 78–100 in R. H. Webb, L. F. Fenstermaker, J. S. Heaton, D. L. Hughson, E. V. McDonald, and D. M. Miller, editors. The Mojave Desert: ecosystem processes and sustainability. University of Nevada Press, Las Vegas, Nevada, USA.
Allen, E. B. and L. H. Geiser. 2011. North American Deserts. In L.H. Pardo, M.J. Robin-Abbott and C.T. Driscoll (Eds.). Assessment of Nitrogen Deposition Effects and Empirical Critical Loads of Nitrogen for Ecoregions of the United States. General Technical Report NRS–80. U.S. Forest Service, Newtown Square, PA. pp. 133–142. Available at: http://nrs.fs.fed.us/pubs/38109.
Balch, J. K., Bradley, B. A., D’Antonio, C. M., Gomez-Dans, J. 2013. Introduced annual grass increases regional fire activity across the arid western USA (1980–2009). Global Change Biology 19: 173–183.
Brooks, M.L. 2003. Effects of increased soil nitrogen on the dominance of alien annual plants in the Mojave Desert. Journal of Applied Ecology. 40:344–353.
Fenn, M. E. and L. H. Geiser. 2011. Temperate Sierra. In L.H. Pardo, M.J. Robin-Abbott and C.T. Driscoll (Eds.). Assessment of Nitrogen Deposition Effects and Empirical Critical Loads of Nitrogen for Ecoregions of the United States. General Technical Report NRS–80. U.S. Forest Service, Newtown Square, PA. pp. 133–142. Available at: http://nrs.fs.fed.us/pubs/38109.
Floyd-Hanna, L., Hanna, D., Romme, W. H., Crews, T. 2004. Non-native invasions following fire in Southwestern Colorado: Long-term effectiveness of mitigation treatments and future predictions. Joint Fire Science Program, product number 1496–BLM2–454.
Gebow, B. S., and W. L. Halvoson. 2004. Managing Fire in the Northern Chihuahuan Desert: A Review and Analysis of the Literature. USGS Open-File Report SBSC-SDRS–2004–1001. U.S. Geological Survey, Southwest Biological Science Center, Sonoran Desert Research Station, University of Arizona, Tucson, AZ. Available at https://pubs.usgs.gov/of/2005/1157/.
Kohut, B. 2004. Assessing the Risk of Foliar Injury from Ozone on Vegetation in Parks in the Sonoran Desert Network. Available at https://irma.nps.gov/DataStore/Reference/Profile/2181558.
Kohut R.J. 2007. Ozone Risk Assessment for Vital Signs Monitoring Networks, Appalachian National Scenic Trail, and Natchez Trace National Scenic Trail. NPS/NRPC/ARD/NRTR—2007/001. National Park Service. Fort Collins, Colorado. Available at https://www.nps.gov/articles/ozone-risk-assessment.htm
Kohut, B., C. Flanagan, E. Porter, J. Cheatham. 2012. Foliar Ozone Injury on Cutleaf Coneflower at Rocky Mountain National Park, Utah. Western North American Naturalist 72(1): 32–42.
[NPS] National Park Service. 2012. 2006–2010 5–Year Average Ozone Estimates. Air Resources Division: Denver, CO.
Pardo, L. H., M. J. Robin-Abbott, C. T. Driscoll, eds. 2011. Assessment of Nitrogen deposition effects and empirical critical loads of Nitrogen for ecoregions of the United States. Gen. Tech. Rep. NRS–80. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 291 p. Available at: http://nrs.fs.fed.us/pubs/38109.
Rao, L. E., E. B. Allen, and T. Meixner. 2010. Risk-based determination of critical nitrogen deposition loads for fire spread in southern California deserts. Ecological Applications 20:1320–1335.
Schwinning, S., B. I. Starr, N. J. Wojcik, M. E. Miller, J. E. Ehleringer, R. L. Sanford. 2005. Effects of nitrogen deposition on an arid grassland in the Colorado plateau cold desert. Rangeland Ecology and Management. 58: 565–574.
Sullivan, T. J., McDonnell, T. C., McPherson, G. T., Mackey, S. D., Moore, D. 2011a. Evaluation of the sensitivity of inventory and monitoring national parks to nutrient enrichment effects from atmospheric nitrogen deposition: main report. Natural Resource Report NPS/NRPC/ARD/NRR—2011/313. National Park Service, Denver, Colorado. Available at https://www.nps.gov/articles/nitrogen-risk-assessment.htm.
Sullivan, T. J., McDonnell, T. C., McPherson, G. T., Mackey, S. D., Moore, D. 2011b. Evaluation of the sensitivity of inventory and monitoring national parks to nutrient enrichment effects from atmospheric nitrogen deposition: Chihuahuan Desert Network (CHDN). Natural Resource Report NPS/NRPC/ARD/NRR—2011/330. National Park Service, Denver, Colorado. Available at https://irma.nps.gov/DataStore/Reference/Profile/2168613.
Sullivan, T. J., McPherson, G. T., McDonnell, T. C., Mackey, S. D., Moore, D. 2011c. Evaluation of the sensitivity of inventory and monitoring national parks to acidification effects from atmospheric sulfur and nitrogen deposition: main report. Natural Resource Report NPS/NRPC/ARD/NRR—2011/349. National Park Service, Denver, Colorado. Available at https://www.nps.gov/articles/acidification-risk-assessment.htm.
Sullivan, T. J., McPherson, G. T., McDonnell, T. C., Mackey, S. D., Moore, D. 2011d. Evaluation of the sensitivity of inventory and monitoring national parks to acidification effects from atmospheric sulfur and nitrogen deposition: Chihuahuan Desert Network (CHDN). Natural Resource Report NPS/NRPC/ARD/NRR—2011/353. National Park Service, Denver, Colorado. Available at https://irma.nps.gov/DataStore/Reference/Profile/2170574.
Sullivan T.J. 2016. Air quality related values (AQRVs) in national parks: Effects from ozone; visibility reducing particles; and atmospheric deposition of acids, nutrients and toxics. Natural Resource Report. NPS/NRSS/ARD/NRR—2016/1196. National Park Service. Fort Collins, Colorado. Available at https://www.nps.gov/articles/aqrv-assessment.htm.
Zak, J. 2006. Impacts of Atmospheric Nitrogen Deposition and Climate Change on Desert Ecosystems. Big Bend National Park. NPS Final Report. 15 pp.