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Studies and Monitoring

Sequoia & Kings Canyon National Parks

Sequoia & Kings Canyon National Parks (NPs), California, have their own unique environmental concerns based on their particular ecology. Air quality studies and monitoring programs at Sequoia & Kings Canyon NPs focus on ozone, nitrogen deposition, toxic air contaminants, and visibility. Click on the tabs below to review air quality studies and key scientific references at Sequoia & Kings Canyon NPs, as well as to access information on air quality monitoring in the parks.

  • Studies & Projects
  • Monitoring & Data
  • Key References

Ongoing research in Sequoia & Kings Canyon NPs, California:

Ground-Level Ozone Impacts

High ozone levels on the west edge of the Sierra Nevada causes widespread and severe injury to ponderosa and Jeffrey pines in the parks (Arbaugh et al. 1998). Chronic, long-term ozone exposure has reduced tree growth in some locations (Peterson et al. 1987; Ewell et al. 1989; Peterson et al. 1991; Duriscoe and Stolte 1992; Peterson and Arbaugh 1992). Needle injury has also been found in giant sequoia seedlings (Grulke and Miller 1994; Miller and Grulke 1994 [pdf, 2.04 MB]). The parks have ongoing programs to monitor ozone injury, forest condition, and productivity. In addition to harming trees, ozone concentrations in the parks frequently exceed standards set by the U.S. Environmental Protection Agency to protect human health. Park managers continue to work on a variety of programs related to ozone monitoring, research, and emissions reductions.

Sulfur & Nitrogen Impacts

High elevation lakes and streams in the parks are extremely dilute. Streams become temporarily acidified during snowmelt, as accumulated acids from nitrogen and sulfur deposition are released from the snow (Stoddard 1995). In addition, nitrogen by itself causes fertilization, which can upset the balance of natural ecosystems (Sickman 2003). Preliminary research has identified the nitrogen critical load for the most sensitive of aquatic plants (i.e., diatoms) as 1.4 kg/ha/yr (Saros 2009 [pdf, 565 KB]). Follow-up research is underway to determine the nitrogen critical load for high elevation lakes across the Sierra Nevada, including at Sequoia & Kings Canyon NPs. The nitrogen critical load for lichen communities in the mixed conifer forests of the parks has been determined to be 3.1 kg/ha/yr (Fenn et al. 2008). Above this critical load, certain lichen species decline. Current N deposition reaches 6–7 kg/ha/yr (Sickman et al. 2001), suggesting that deposition reductions are needed to protect and restore certain park ecosystems. Sources of nitrogen in the parks include the Central Valley and San Francisco Bay Area (LeNoir et al. 1999; Bytnerowicz et al. 2002; Hageman et al. 2006).

Airborne Toxic Contaminants Impacts

Air currents transport contaminants such as pesticides, industrial pollutants and heavy metals from their sources, and deposit these toxics in rain, snow, and dryfall at Sequoia & Kings Canyon NPs (McConnell et al. 1998; Hageman et al. 2006; Landers et al. 2008). The Western Airborne Contaminants Assessment Project found airborne contaminants in fish, vegetation, snow and lake sediments in the parks. Pesticide and mercury concentrations in some park fish exceeded human and/or wildlife health thresholds (Ackerman et al. 2008; Landers et al. 2008; Schwindt et al. 2008). Research suggests that pesticides from the adjacent Central Valley contributed to the disappearance of the Foothill Yellow-legged Frog, and in the ongoing decline of other amphibians in these parks, including Mountain Yellow-legged Frogs (McConnell et al. 1998; LeNoir et al. 1999; Sparling et al. 2001; Fellers et al. 2004; Hageman et al. 2006; Davidson and Knapp 2007). The Sierra Nevada—Southern Cascades (SNSC) Contaminants Workshop was held to address regional concerns regarding contaminant distribution and effects. A research and monitoring strategy is under development to examine conditions and trends in toxic air contaminants in the region. Additional research is examining whether contaminants disrupt reproductive organs in park fish.

Air quality monitoring information and data access:

Air Pollutant/Impact

Monitoring Program

Sites and Data Access

Nitrogen Wet deposition NADP/NTN
Dry deposition CASTNet
Mercury NADP/MDN
Other Toxics & Mercury WACAP
Visibility IMPROVE

Abbreviations in the above table:

    CASTNet: EPA Clean Air Status and Trends Network
    GPMP: Gaseous Pollutant Monitoring Program
    IMPROVE: Interagency Monitoring of Protected Visual Environments
    MDN: Mercury Deposition Network
    NADP: National Atmospheric Deposition Program
    NPS: National Park Service
    NTN: National Trends Network
    VIEWS: Visibility Information Exchange Web System
    WACAP: Western Airborne Contaminants Assessment Project

For more information regarding monitoring and data assessments conducted by the National Park Service, link to the NPS Air Quality Monitoring Program or to the NPS Air Quality Monitoring History Database for a history of active and inactive monitoring sites at Sequoia & Kings Canyon NPs.

Key air quality related references from Sequoia & Kings Canyon NPs, California:

Ackerman, L. K., Schwindt, A. R., Massey Simonich S. L., Koch, D. C., Blett, T. F., Schreck, C. B., Kent, M. L., Landers, D. H. 2008. Atmospherically Deposited PBDEs, Pesticides, PCBs, and PAHs in Western U.S. National Park Fish: Concentrations and Consumption Guidelines. Environmental Science & Technology 42: 2334–2341.

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.

Bytnerowicz, A., Dawson, P. J., Morrison, C. L. and Poe, M. P. 1992. Atmospheric Dry Deposition of Pines in the Eastern Brook Lake Watershed, Sierra Nevada, California. Atmospheric Environment Part A—General Topics 26: 3195–3201.

Bytnerowicz, A., Dawson, P. J., Morrison, C. L. and Poe, M. P. 1991. Deposition of Atmospheric Ions to Pine Branches and Surrogate Surfaces in the Vicinity of Emerald Lake Watershed, Sequoia National Park. Atmospheric Environment Part A—General Topics 25: 2203–2210.

Bytnerowicz, A., Tausz, M., Alonso, R., Jones, D., Johnson, R. and Grulke, N. 2002. Summer-time distribution of air pollutants in Sequoia National Park, California. Environmental Pollution 118: 187–203.

Clow, D. W., Striegl, R. G., Campbell, D. H., and Mast, M. A. 2000. Survey of high-altitude lake chemistry in national parks in the western United States, In Proceedings of the International Symposium on High Mountain Lakes and Streams. Innsbruck, Austria.

Davidson, C. and Knapp, R. A. 2007. Multiple stressors and amphibian declines: Dual impacts of pesticides and fish on yellow-legged frogs. Ecol Appl 17: 587–597.

Duriscoe, D. M. and Stolte, K. W. 1992. Decreased foliage production and longevity observed in ozone-injured Jeffrey and ponderosa pines in Sequoia National Park, California. In Tropospheric Ozone and the Environment: Effects Modeling and Control. Air Waste Manage. Assoc.: Pittsburgh, PA. pp. 663–680.

Ewell, D. M., Mazzu, L. C., and Duriscoe, D. M. 1989. Specific leaf weight and other characteristics of ponderosa pine as related to visible ozone injury. Air Pollution Control Assoc. 16: 411–418.

Fellers, G. M., McConnell, L. L., Pratt, D., Datta, S. 2004. Environmental Toxicology and Chemistry 23 (9): 2170–2177.

Fenn, M. E., Jovan, S., Yuan, F., Geiser, L., Meixner, T., Gimeno, B. S. 2008. Empirical and simulated critical loads for nitrogen deposition in California mixed conifer forests. Environmental Pollution 155: 492–511.

Grulke, N. E. and Miller, P. R. 1994. Changes in Gas-Exchange Characteristics during the Life-Span of Giant Sequoia—Implications for Response to Current and Future Concentrations of Atmospheric Ozone. Tree Physiology 14: 659–668.

Hageman, K. J., Simonich, S. L., Campbell, D. H., Wilson, G. R., Landers, D. H. 2006. Atmospheric deposition of current-use and historic-use pesticides in snow at national parks in the Western United States. Environmental Science & Technology 40: 3174–3180.

[IMPROVE] Interagency Monitoring of Protected Visual Environments. 2010.Improve Summary Data. Available at

Jarman W. M. 1994. Levels and trends of DDE in California peregrines. U.S. Fish and Wildlife Service Report. 16 pp.

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., Simonich, S. L., Jaffe, D. A., Geiser, L. H., Campbell, D. H., Schwindt, A. R., Schreck, C. B., Kent, M. L., Hafner, W. D., Taylor, H. E., Hageman, K. J., Usenko, S., Ackerman, L. K., Schrlau, J. E., Rose, N. L., Blett, T. F., Erway, M. M. 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, OR. Available at

LeNoir, J. S., McConnell, L. L., Fellers, G. M., Cahill, T. M., Seiber, J. N. 1999. Summertime transport of current-use pesticides from California’s Central Valley to the Sierra Nevada Mountain Range, USA. Environmental Toxicology and Chemistry 18: 2715–2722.

Leydecker, A., Sickman, J. O. and Melack, J. M. 1999. Episodic lake acidification in the Sierra Nevada, California. Water Resources Research 35: 2793–2804.

McConnell, L. L., LeNoir, J. S., Datta, S. and Seiber, J. N. 1998. Wet deposition of current-use pesticides in the Sierra Nevada mountain range, California, USA. Environmental Toxicology and Chemistry 17: 1908–1916.

Miller, P. R. and Grulke, N. E. 1994. Air pollution effects on giant sequoia ecosystems. In P. S. Aune (tech. coord.). Proceedings of the symposium on giant sequoias: their place in the ecosystem and society. USDA Forest Service Gen. Tech. Rep. PSW-GTR-151. pp. 90–98. Available at
(pdf, 2.04 MB).

Peterson, D. L. and Arbaugh, M. J. 1992. Mixed conifer forests of the Sierra Nevada. In R. K. Olson, D. Binkley, and M. Böhm (eds.), Response of Western Forests to Air Pollution. Springer-Verlag, New York. pp. 433–459.

Peterson, D. L., Arbaugh, M. J., Robinson, L. J. 1991. Regional growth changes in ozone-stressed ponderosa pine (Pinus ponderosa) in the Sierra Nevada, California, USA. The Holocene 1: 50–61.

Peterson, D. L., Arbaugh, M. J., Wakefield, V. A. and Miller, P. R. 1987. Evidence of growth reduction in ozone-injured Jeffrey pine (Pinus jeffreyi Grev. and Balf.) in Sequoia and Kings Canyon National Parks. Journal of the Air Pollution Control Association 37: 906–912.

Saros, J. 2009. Inferring Critical Nitrogen Deposition Loads to Alpine Lakes of Western National Parks and Diatom Fossil Records. National Park Service: Final Report. 13 pp. Available at
(pdf, 565 KB).

Schwindt, A. R., Fournie, J. W., Landers, D. H., Schreck, C. B., Kent, M. 2008. Mercury Concentrations in Salmonids from Western U.S. National Parks and Relationships with Age and Macrophage Aggregates. Environmental Science & Technology 42 (4): 1365–1370.

Sickman, J. O., Leydecker, A., and Melack, J. M. 2001. Nitrogen mass balances and abiotic controls on N retention and yield in high-elevation catchments of the Sierra Nevada, California, United States. Water Resources Research 37: 1445–1461.

Sickman, J. O., Melack, J. M. and Clow, D. W. 2003. Evidence for nutrient enrichment of high-elevation lakes in the Sierra Nevada, California. Limnology and Oceanography 48: 1885–1892.

Sparling, D. W., Fellers G. M., McConnell L. L. 2001. Pesticides and amphibian population declines in California, USA. Environmental Toxicology and Chemistry 20: 1591–1595.

Stoddard, J. L. 1995. Episodic Acidification During Snowmelt of High Elevation Lakes in the Sierra Nevada Mountains of California. Water, Air and Soil Pollution. 85:353–358.

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

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: Sierra Nevada Network (SIEN). Natural Resource Report NPS/NRPC/ARD/NRR—2011/330. National Park Service, Denver, Colorado. Available at (pdf, 7.4 MB).

Sullivan, T. J., Peterson, D. L., Blanchard, C. L. 2001. Assessment of Air Quality and Air Pollutant Impacts in Class I National Parks of California. National Park Service. 421 pp. Available at (pdf, 6.3 MB).

Warner, T. E., Wallner, D. W. and Vogler, D. R. 1983. Ozone injury to ponderosa and Jeffrey pines in Sequoia & Kings Canyon National Parks. In Proceedings First Biennial Conference of Research in California’s National Parks. pp. 1–7.

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Pollutants including sulfur, nitrogen, fine particles and ozone affect resources such as streams, soils, and scenic vistas. Find out how on our Sequoia & Kings Canyon NPs Air Pollution Impacts web page.

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Last Updated: June 14, 2011