Series: Park Air Profiles

Park Air Profiles - Redwood National and State Parks

Visitor on a trail in Redwood NSP
Visitors come to Redwood NSP to enjoy scenic views of the California coastline, river-ways, and the tallest trees on Earth.

Air quality at Redwood National and State Parks

Most visitors expect clean air and clear views in parks. Redwood National and State Park (NSP), California, home to the world’s tallest trees, is upwind from many pollution sources. Still, emissions from nearby logging and mining operations, wood smoke, vehicles, power plants, and agriculture can harm the park’s natural and scenic resources such as, surface waters, plants, and visibility. The National Park Service works to address air pollution effects at Redwood NSP, and in parks across the U.S., through science, policy and planning, and by doing our part.

Visibility

Coastal view on Yurok loop trail Clean, clear air is essential to appreciating the scenic vistas at Redwood NSP.

Many visitors come to Redwood NSP to enjoy views of primeval redwood forests against the rugged coastline of the Pacific Ocean. 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. Naturally-occurring marine fog, which also limits visibility at the park, provides necessary water to the moisture-loving redwood needles. Significant improvement in park visibility on both the clearest and haziest days have been documented since the late 1980’s Still, visibility 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 110 miles (without the effects of pollution) to about 90 miles because of pollution at the park
  • Reduction of the visual range to below 45 miles on high pollution days

Visit the NPS air quality conditions and trends website for park-specific visibility information. Redwood NSP has been monitoring visibility since 1988. Explore air monitoring »

Nitrogen and sulfur

Nitrogen and sulfur compounds deposited from the air may have harmful effects, including acidification, on soils, lakes, ponds, and streams. Atmospheric nitrogen and sulfur inputs are relatively low at Redwood NSP, but the park's steeper slopes and low buffering capacity make certain streams susceptible to acidification (Sullivan et al. 2011c; Sullivan et al. 2011d; Dinger 2010). Additionally, some plants are sensitive to acidification. Search for acid-sensitive plant species found at Redwood NSP.

Excess nitrogen can also lead to nutrient enrichment, a process that changes nutrient cycling and alters plant communities. 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. While Redwood NSP trees and streams are not particularly sensitive to nutrient enrichment (Sullivan et al. 2011a; Sullivan et al. 2011b), some species of forest lichens are very sensitive, and may decrease in abundance as nitrogen increases (Fenn et al. 2010). “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.

Ground-level ozone

Red alder leaves Red Alder is one of the ozone-sensitive species found at Redwood NSP.

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 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. An ozone monitor from 1987–1995 at Redwood NSP reported low ozone concentrations compared to other California parks (Sullivan et al. 2001). A risk assessment that concluded that plants in Redwood NSP were at moderate risk of ozone injury on plant leaves (Kohut 2007; Kohut 2004). The U.S. Forest Service did not find ozone injury on trees examined near the park (specifically, in the northern end of the North Coast air basin) (Campbell et al. 2007). However, that survey did not look at understory plants. Some plants are more sensitive to ozone than others. Ozone-sensitive plants in Redwood NSP include Pinus jeffreyi (Jeffrey pine), Alnus rubra (red alder), and Artemisia douglasiana (Sagebrush). Search for more ozone-sensitive plant species found at Redwood NSP.

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

Campbell, S. J., Wanek, R. Coulston, J. W. 2007. Ozone injury in west coast forests: 6 years of monitoring. General Technical Report. 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/pnw-beta/publications/ozone-injury-west-coast-forests-6-years-monitoring.

Dinger, E. C. 2010. Integrated aquatic community and water quality monitoring of wadeable streams in the Klamath Network – Annual report. 2009 results from pilot project in Redwood National and State Parks. National Park Service, Fort Collins, Colorado. Available at https://irma.nps.gov/DataStore/Reference/Profile/2171612.

Fenn, M. E., Allen, E. B., Weiss, S. B., Jovan, S., Geiser, L. H., Tonnesen, G. S., Johnson, R. F., Rao, L. E., Gimeno, B. S., Yuan, F., Meixner, T., Bytnerowicz, A. 2010. Nitrogen critical loads and management alternatives for N-impacted ecosystems in California. Journal of Environmental Management 91 (12): 2404–2423.

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.

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

Rao L. E., Allen E. B., Meixner T. 2010. Risk-based determination of critical nitrogen deposition loads for fire spread in southern California deserts. Ecological Applications 20 (5): 1320–1335.

Sullivan T.J., Peterson, D.L., Blanchard, C.L., Tannebaum, S.J. 2001. Assessment of Air Quality and Air Pollutant Impacts in Class I National Parks of California. National Park Service. Available at https://irma.nps.gov/DataStore/Reference/Profile/2082158.

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: Klamath Network (KLMN). Natural Resource Report NPS/NRPC/ARD/NRR—2011/313. National Park Service, Denver, Colorado. Available at https://irma.nps.gov/DataStore/Reference/Profile/2168683.

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: Klamath Network (KLMN). Natural Resource Report NPS/NRPC/ARD/NRR—2011/349. National Park Service, Denver, Colorado. Available at https://irma.nps.gov/DataStore/Reference/Profile/2170588.

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.