Park Air Profiles - Great Sand Dunes National Park & Preserve

Cottonwood trees in front of sand dunes in Great Sand Dunes NP & Pres
Visitors come to Great Sand Dunes NP & Pres to enjoy scenic views of the Rocky Mountains and the tallest sand dunes in North America.

Air quality at Great Sand Dunes National Park & Preserve

Most visitors expect clean air and clear views in parks. Great Sand Dunes National Park & Preserve (NP & Pres), Colorado, home to the tallest dunes in North America, is downwind of many pollution sources. Air pollutants blown into the park can harm natural and scenic resources such as soils, surface waters, plants, wildlife, and visibility. The National Park Service works to address air pollution effects at Great Sand Dunes NP & Pres, and in parks across the U.S., through science, policy and planning, and by doing our part.

Nitrogen and sulfur

Nitrogen and sulfur compounds deposited from the air may have harmful effects, including acidification, of alpine lakes and loss of plant diversity from nitrogen enrichment in alpine tundra. High elevation ecosystems in the park are particularly vulnerable to nitrogen and sulfur deposition. These systems receive more deposition than lower elevation areas because of greater amounts of snow and rain. Additionally, short growing seasons and shallow soils limit the capacity of soils and plants to buffer or absorb sulfur and nitrogen. Risk assessments concluded that ecosystems in the park were at high risk from acidification and very high risk from nutrient enrichment (Nanus et al. 2009; Sullivan et al. 2011a; Sullivan et al. 2011b, Sullivan et al. 2011c; Sullivan et al. 2011d). Some plants are more sensitive to acidification than others, search for acid-sensitive plant species found at Great Sand Dunes NP & Pres.

Nitrogen and sulfur compounds have been detected in snowpack samples collected at the park (Ingersoll et al. 2007). 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).

Visit the NPS air quality conditions and trends website for park-specific nitrogen and sulfur deposition information.

Mercury and toxics

Airborne mercury, and other toxic air contaminants, when deposited are known to harm birds, salamanders, fish and other wildlife, and cause human health concerns. These substances enter the food chain and accumulate in the tissue of organisms causing reduced reproductive success, impaired growth and development, and decreased survival.

Air currents transport toxic contaminants such as pesticides, industrial pollutants, and mercury from their sources, and deposit these toxics in rain, snow, and dry deposition (e.g., dust) at Great Sand Dunes NP & Pres. Research findings from the Western Airborne Contaminants Assessment Project (WACAP) and Rocky Mountain Regional Snowpack Chemistry Monitoring Study found airborne contaminants in park air, vegetation, snow, and water (Ingersoll et al. 2007; Keteles 2011; Landers et al. 2010; Landers et al. 2008). Concentrations of current-use pesticides in air and vegetation samples at the park were elevated when compared to other national parks (Landers et al. 2010; Landers et al. 2008).

Follow-up research is examining the extent to which contaminants are causing abnormalities in reproductive organs in fish at Great Sand Dunes NP & Pres and other parks. Fish from other western parks, including Rocky Mountain NP and Glacier NP, have been found with reproductive abnormalities associated with airborne contaminant exposure (Schwindt et al. 2009). In addition, as part of the Dragonfly Mercury Project, dragonfly larvae have been collected by citizen scientists at the park and analyzed for mercury. See project results.

Ground-level ozone

Quaking Aspen trees are one of the ozone sensitive species found at Great Sand Dunes NP & Pres. Quaking Aspen trees are one of the ozone sensitive species found at Great Sand Dunes NP & Pres.

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 number of ozone-sensitive plants in Great Sand Dunes NP & Pres including Rudbeckia laciniata (cut-leaf coneflower) and Populus tremuloides (quaking aspen). 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 Great Sand Dunes NP & Pres.

Visit the NPS air quality conditions and trends website for park-specific ozone information.

Visibility

Sand Creek Basin in Great Sand Dunes NP & Pres Clean, clear air is essential to appreciating the scenic vistas at Great Sand Dunes NP & Pres.

Visitors come to Great Sand Dunes NP & Pres to enjoy views of impressive sand dunes against the backdrop of the Sangre de Cristo mountain range. 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, and dust reduce visibility as well. Significant improvements in park visibility on clearest days have been documented since the 1990’s. However, no significant trends have occurred on haziest days and visibility in the park still needs improvement to reach the Clean Air Act goal of no human caused impairment.

Visibility effects:
  • Reduction of the average natural visual range from about 170 miles (without the effects of pollution) to about 125 miles because of pollution at the park
  • Reduction of the visual range to below 85 miles on high pollution days

Visit the NPS air quality conditions and trends website for park-specific visibility information. Great Sand Dunes NP & Pres has been monitoring visibility since 1988. Explore air monitoring »

Baron, J. S. 2006. Hindcasting nitrogen deposition to determine an ecological critical load. Ecological Applications 16: 433–439.

Binkley, D., Giardina, C., Dockersmith, I., Morse, D., Scruggs, M., Tonnessen, K. 1997. Status of Air Quality and Related Values in Class I National Parks and Monuments of the Colorado Plateau. National Park Service, Air Resources Division, Denver, Colorado. Chapter 10: Great Sand Dunes National Park. Available at https://irma.nps.gov/DataStore/Reference/Profile/585485

Bowman, W. D., Gartner, J. R., Holland, K., Wiedermann, M. 2006. Nitrogen critical loads for alpine vegetation and terrestrial ecosystem response: are we there yet? Ecological Applications 16(3): 1183–1193.

Ingersoll, G. P., Mast, M. A., Nanus, L., Handran, H. H., Manthorne, D. J., and Hultstrand, D. M. 2007. Rocky Mountain snowpack chemistry at selected sites, 2004: U.S. Geological Survey Open-File Report 2007-1045, 15 p. Available at https://pubs.usgs.gov/of/2007/1045/

Keteles, K. 2011. Screening for Pesticides in High Elevation Lakes in Federal Lands. EPA Final Report. Denver, CO. 11 pp. Available at https://irma.nps.gov/DataStore/Reference/Profile/2184330

Kohut, R., Flanagan, C., Cheatham, J., Porter, E. Foliar Ozone Injury on Cutleaf Coneflower at Rocky Mountain National Park, Colorado, U.S.A. In Prep.

Kohut, R. 2004. Assessing the Risk of Foliar Injury from Ozone on Vegetation in Parks in the Rocky Mountain Network. Available at https://irma.nps.gov/DataStore/Reference/Profile/2181542

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

Landers, D. H., Simonich, S. M., Jaffe, D., Geiser, L., Campbell, D. H., Schwindt, A., Schreck, C., Kent, M., Hafner, W., Taylor, H. E., Hageman, K., Usenko, S., Ackerman, L., Schrlau, J., Rose, N., Blett, T., Erway, M. M. 2010. The Western Airborne Contaminant Assessment Project (WACAP): An Interdisciplinary Evaluation of the Impacts of Airborne Contaminants in Western U.S. National Parks. Environmental Science and Technology 44: 855–859.

Landers, D. H., S. L. Simonich, D. A. Jaffe, L. H. Geiser, D. H. Campbell, A. R. Schwindt, C. B. Schreck, M. L. Kent, W. D. Hafner, H. E. Taylor, K. J. Hageman, S. Usenko, L. K. Ackerman, J. E. Schrlau, N. L. Rose, T. F. Blett, and M. M. Erway. 2008. The Fate, Transport, and Ecological Impacts of Airborne Contaminants in Western National Parks (USA). EPA/600/R—07/138. U.S. Environmental Protection Agency, Office of Research and Development, NHEERL, Western Ecology Division, Corvallis, Oregon. Available at https://irma.nps.gov/DataStore/Reference/Profile/660829.

Nanus, L., Williams, M. W., Campbell, D. H., Tonnessen, K. A., Blett, T., and Clow, D. W. 2009. Assessment of lake sensitivity to acidic deposition in national parks of the Rocky Mountains. Ecological Applications 19(4): 961–973.

Porter, E., Blett, T., Potter, D.U., Huber, C. 2005. Protecting resources on federal lands: Implications of critical loads for atmospheric deposition of nitrogen and sulfur. BioScience 55(7): 603–612. https://doi.org/10.1641/0006-3568(2005)055[0603:PROFLI]2.0.CO;2

Porter, E. and Johnson, S. 2007. Translating science into policy: Using ecosystem thresholds to protect resources in Rocky Mountain National Park. Environmental Pollution 149: 268–280.

Saros, J. E., Clow, D. W., Blett, T., Wolfe, A. P. 2010. Critical nitrogen deposition loads in high-elevation lakes of the western U.S. inferred from paleolimnological records. Water, Air, and Soil Pollution 216(1–4): 193–202.

Schwindt, A. R., Kent, M. L., Ackerman, L. K., Massey Simonich, S. L., Landers, D. H., Blett, T., Schreck, C. B. 2009. Reproductive Abnormalities in Trout from Western U.S. National Parks. Transactions of the American Fisheries Society 138: 522–531.

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: Rocky Mountain Network (ROMN). Natural Resource Report NPS/NRPC/ARD/NRR—2011/324. National Park Service, Denver, Colorado. Available at https://irma.nps.gov/DataStore/Reference/Profile/2168730

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: Rocky Mountian Network (ROMN). Natural Resource Report NPS/NRPC/ARD/NRR—2011/360. National Park Service, Denver, Colorado. Available at https://irma.nps.gov/DataStore/Reference/Profile/2170599

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

Last updated: July 3, 2018