Air Quality at Lassen Volcanic National Park
Most visitors expect clean air and clear views in parks. Lassen Volcanic National Park (NP), California, well known for volcanic landforms and interesting geology, lies downwind of the populated Sacramento Valley and areas of agriculture and manufacturing. Air pollutants blown into the park can harm natural and scenic resources such as surface waters, plants, and visibility. The National Park Service works to address air pollution effects at Lassen Volcanic NP, and in parks across the U.S., through science, policy and planning, and by doing our part.
Nitrogen and Sulfur
Nitrogen (N) and sulfur (S) compounds deposited from the air may have harmful effects on ecosystem processes. Healthy ecosystems can naturally buffer a certain amount of pollution, but once a threshold is passed the ecosystem may respond negatively. This threshold is the critical load, or the amount of pollution above which harmful changes in sensitive ecosystems occur (Porter 2005). N and S deposition change ecosystems through eutrophication (N deposition) and acidification (N + S deposition). Eutrophication increases soil and water nutrients which causes some species to grow more quickly and changes community composition. Ecosystem sensitivity to nutrient N enrichment at Lassen Volcanic National Park (LAVO) relative to other national parks is high (Sullivan et al. 2016); for a full list of N sensitive ecosystem components, see: NPS ARD 2019. Acidification leaches important cations from soils, lakes, ponds, and streams which decreases habitat quality. Ecosystem sensitivity to acidification at LAVO relative to other national parks is very high (Sullivan et al. 2016); to search for acid-sensitive plant species, see: NPSpecies.
From 2017-2019 total N deposition in LAVO ranged from 3.0 to 3.7 kg-N ha-1 yr-1 and total S deposition ranged from 0.7 to 1.0 kg-S ha-1 yr-1 based on the TDep model (NADP, 2018). LAVO has been monitoring atmospheric N and S deposition since 2000, see the conditions and trends website for park-specific information.
In some areas of the country, increased N deposition has allowed weedy annual grasses to invade shrublands and grasslands, replacing native plants that evolved under N-poor conditions.
Volcanic formations at LAVO, including boiling mud pots and fumaroles, naturally emit S compounds such as sulfur dioxide and hydrogen sulfide. Concentrations of S from volcanic emissions are relatively low and are not known to cause acidification on sensitive resources like high elevation lakes.
Alpine ecosystem effects
Alpine environments are particularly vulnerable to large inputs of reactive nitrogen because of the sparse cover of vegetation, short growing seasons, large areas of exposed bedrock and talus, and snowmelt nutrient releases (Williams et al., 1996; Nanus et al., 2012). Approximately 7% of the land area in LAVO is alpine (~328 km2 above 1550 m). McClung et al. (2020) compared the 2015 estimated total N deposition (TDep; NADP, 2018) to the critical load of N for an increase in alpine sedge growth (alpine plant critical load = 3 kg-N ha-1yr-1) and the critical load of N for alpine soil nitrate leaching (alpine soil critical load = 10 kg-N ha-1yr-1; Bowman et al., 2012). They found that deposition exceeded the alpine plant critical load in 88% of the park’s alpine area, but was below the alpine soil critical load throughout the park’s entire alpine area.
Epiphytic macrolichen community responses
Epiphytic macrolichens grow on tree trunks, branches, and boles. Since these lichens grow above the ground, they obtain all their nutrients directly from precipitation and the air. Many epiphytic lichen species have narrow environmental niches and are extremely sensitive to changes in air pollution. Geiser et al. (2019) used a U.S. Forest Service national survey to develop critical loads of nitrogen (N) and critical loads of sulfur (S) to prevent more than a 20% decline in four lichen community metrics: total species richness, pollution sensitive species richness, forage lichen abundance, and cyanolichen abundance.
McCoy et al. (2021) used forested area from the National Land Cover Database to estimate the impact of air pollution on epiphytic lichen communities. Forested area makes up 269 km2 (61.9%) of the land area of Lassen Volcanic National Park.
- N deposition exceeded the 3.1 kg-N ha-1 yr-1 critical load to protect N-sensitive lichen species richness in 31.9% of the forested area.
- S deposition was below the 2.7 kg-S ha-1 yr-1 critical load to protect S-sensitive lichen species richness in every part of the forested area.
For exceedances of other lichen metrics and the predicted decline of lichen communities see Appendices A and B of McCoy et al. (2021).
Additional modeling was done on 459 lichen species to test the combined effects of air pollution and climate gradients (Geiser et al. 2021). A critical load indicative of initial shifts from pollution-sensitive toward pollution-tolerant species occurred at 1.5 kg-N ha-1 yr-1 and 2.7 kg-S ha-1 yr-1 even under changing climate regimes.
Plant species response
Plants vary in their tolerance of eutrophication and acidification, and some plant species respond to nitrogen (N) or sulfur (S) pollution with declines in growth, survival, or abundance on the landscape. Horn et al. (2018) used the U.S. Forest Service national forest survey to develop critical loads of N and critical loads of S to prevent declines in growth or survival of sensitive tree species. Clark et al. (2019) used a database of plant community survey to develop critical loads of N and critical loads of S to prevent a decline in abundance of sensitive herbaceous plant species. According to NPSpecies, Lassen Volcanic National Park contains:
- 5 N-sensitive tree species and 18 N-sensitive herbaceous species.
- 6 S-sensitive tree species and 15 S-sensitive herbaceous species.
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.
Mercury and toxics effects:
- Presence of mercury in high elevation lakes in the park (Krabbenhoft et al. 2002).
- Concentrations of mercury in fish at three lakes in the park ranged from low to high. Mercury concentrations were lowest in fish from Summit Lake. Fish from Ridge Lake and Horseshoe Lake had concentrations above the mean for all fish across 19 western national parks (Eagles-Smith et al. 2014).
- Elevated concentrations of combustion by-products (PAHs), current-use pesticides (endosulfans, dacthal), and historic-use pesticides (DDTs, HCB) found in park air and vegetation samples (Landers et al. 2010; Landers et al. 2008)
- High concentrations of dacthal in park fish (Flanagan Pritz et al 2014).
- Current-use pesticides (chlorpyrifos, dacthal, endosulfans) are particularly high in fish from parks in the Sierra Nevada (including Lassen Volcanic NP) compared to levels in fish from parks in Alaska and the Cascades (Flanagan Pritz et al 2014).
- Low frequency of intersex fish (the presence of both male and female reproductive structures in the same fish) found in the park, which indicates minimal exposure to contaminants (Schreck and Kent 2013).
- Through the Dragonfly Mercury Project, dragonfly larvae have been collected by citizen scientists at the park and analyzed for mercury. See project results.
Visitors come to Lassen Volcanic NP to enjoy spectacular volcanic landforms and relatively undisturbed natural resources, including forests, lakes, and streams. 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.
- Reduction of the average natural visual range from about 165 miles (without pollution) to about 130 miles because of pollution at the park
- Reduction of the visual range to below 70 miles on high pollution days
Explore scenic vistas through live webcams at Lassen Volcanic National Park.
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. In addition to the local and regional influence of ozone, research indicates global background ozone levels and nearby fires impact ozone exposures at the park (Jaffe et al. 2003; Jaffe et al. 2008).
Over the course of a growing season, ozone can damage plant tissues making it harder for plants to produce and store food. It also weakens plants making them less resistant to disease and insect infestations. Some plants are more sensitive to ozone than others. Assessments conducted in the late 1990’s discovered foliar ozone injury on greater than 25% of the Pinus jeffreyi (Jeffrey pine) and Pinus ponderosa (ponderosa pine) trees sampled in the park (Arbaugh et al. 1998). More recently, the U.S. Forest Service has found ozone injury on trees examined near the park in Lassen County (Campbell et al. 2007). Other plants sensitive to ozone include Populus tremuloides (quaking aspen) and Populus trichocarpa (black cottonwood). Search ozone-sensitive plant species found at Lassen Volcanic NP.
Visit the NPS air quality conditions and trends website for park-specific ozone information. Lassen Volcanic NP has been monitoring ozone since 1987. Check out the live ozone and meteorology data from Lassen Volcanic NP and explore air monitoring »
Arbaugh, M. J., Miller, P. R., Carroll, J. J., Takemoto, B., and Procter, T. 1998. Relationships of ozone exposure to pine injury in the Sierra Nevada and San Bernardino Mountains of California, USA. Environ. Pollut. 101: 291–301.
Bowman W, Murgel J, Blett T, Porter E. 2012. Nitrogen critical loads for alpine vegetation and soils in Rocky Mountain National Park. Journal of Environmental Management. 103:165-171
Campbell, S. J., Wanek, R., Coulston, J. W. 2007. Ozone injury in west coast forests: 6 years of monitoring. Gen. Tech. Rep. PNW-GTR-722. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 53 p. Available at https://www.fs.usda.gov/treesearch/pubs/27926
Clark, C.M., Simkin, S.M., Allen, E.B. et al. Potential vulnerability of 348 herbaceous species to atmospheric deposition of nitrogen and sulfur in the United States. Nat. Plants 5, 697–705 (2019). https://doi.org/10.1038/s41477-019-0442-8
Eagles-Smith, C.A., J.J. Willacker, and C.M.Flanagan Pritz. 2014. Mercury in fishes from 21 national parks in the Western United States—Inter and intra-park variation in concentrations and ecological risk: U.S. Geological Survey Open-File Report 2014-1051, 54 p. Available at: http://dx.doi.org/10.3133/ofr20141051.
Flanagan Pritz, C. M., J. E. Schrlau, S. L. Massey Simonich, T. F. Blett. 2014. Contaminants of Emerging Concern in Fish from Western U.S. and Alaskan National Parks – Spatial Distribution and Health Thresholds. Journal of American Water Resources Association 50 (2): 309–323. Available at https://irma.nps.gov/App/Reference/Profile/2210538.
Geiser, Linda & Nelson, Peter & Jovan, Sarah & Root, Heather & Clark, Christopher. (2019). Assessing Ecological Risks from Atmospheric Deposition of Nitrogen and Sulfur to US Forests Using Epiphytic Macrolichens. Diversity. 11. 87. 10.3390/d11060087.
Geiser, Linda & Root, Heather & Smith, Robert & Jovan, Sarah & Clair, Larry & Dillman, Karen. (2021). Lichen-based critical loads for deposition of nitrogen and sulfur in US forests. Environmental Pollution. 291. 118187. 10.1016/j.envpol.2021.118187.
Horn KJ, Thomas RQ, Clark CM, Pardo LH, Fenn ME, Lawrence GB, et al. (2018) Growth and survival relationships of 71 tree species with nitrogen and sulfur deposition across the conterminous U.S.. PLoS ONE 13(10): e0205296. https://doi.org/10.1371/journal.pone.0205296
Jaffe, D., Chand, D., Hafner, W., Westerling, A., and Spracklen, D. 2008. Influence of fires on O-3 concentrations in the western US. Environmental Science & Technology 42 (16): 5885–5891.
Jaffe, D., Price, H., Parrish, D., Goldstein, A., and Harris, J. 2003. Increasing background ozone during spring on the west coast of North America. Geophysical Research Letters 30 (12): 1613.
Krabbenhoft, D. P., Olson, M. L., Dewild, J. F., Clow, D. W., Striegl, R. G., Dornblaser, M. M., and VanMetre, P. 2002. Mercury loading and methylmercury production and cycling in high-altitude lakes from the western United States. Water, Air, and Soil Pollution, Focus 2: 233–249.
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.
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.
McClung JJ, Bell MD, Felker-Quinn E. 2021. Extrapolating critical loads of nitrogen for alpine vegetation and assessing exceedance in national parks based on TDep Total N from 2002–2016. Natural Resource Report. NPS/NRSS/ARD/NRR—2021/2240. National Park Service. Fort Collins, Colorado. https://doi.org/10.36967/nrr-2284914
McCoy K., M. D. Bell, and E. Felker-Quinn. 2021. Risk to epiphytic lichen communities in NPS units from atmospheric nitrogen and sulfur pollution: Changes in critical load exceedances from 2001‒2016. Natural Resource Report NPS/NRSS/ARD/NRR—2021/2299. National Park Service, Fort Collins, Colorado. https://doi.org/10.36967/nrr-2287254.
Nanus L, Clow D, Saros J, Stephens V, Campbell D. 2012. Mapping Critical Loads of Nitrogen Deposition for Aquatic Ecosystems in the Rocky Mountains, USA.. Environmental Pollution. 166:125-135
[NADP] National Atmospheric Deposition Program. 2018. NTN Data. Accessed January 20, 2022. Available at http://nadp.slh.wisc.edu/NADP/
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
Schreck, C.B. and M. Kent. 2013. Extent of Endocrine Disruption in Fish of Western and Alaskan National Parks. NPS-OSU Task Agreement J8W07080024. NPS Final Report, 72 pp.
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, CO.
Williams MW, Baron JS, Caine N, Sommerfeld R, Sanford R. 1996. Nitrogen saturation in the Rocky Mountains. Environmental Science & Technology. 30(2):640-646