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This image of Yosemite National Park is a composite of two photographs recorded automatically at the visibility monitoring station in Yosemite Valley. Ninety-nine percent of the time, visibility in the valley is better than that depicted in the right half of the image (“bad” visibility, or less than 10 miles visual range); 1% of the time, visibility is better than that shown in the left half (“excellent” visibility, or greater than 125 miles). Half Dome is circled to show its location.
Annie Esperanza
Air Resources Specialist, Sequoia and Kings Canyon National Parks, California
Judy Rocchio
Air Resources Specialist, Pacific West Region
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| “Class I national parks in California experience some of the best and worst air quality found in any park area in the country.” |
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Back to Chapter 2:Science-Based Management
Articles
Lynx inventories under way in the Intermountain Region
By Laura Hudson
Inventories yield large benefits for Devils Postpile National Monument
By Linda Mutch
Carl Sandburg Home: Biodiversity in a small park
By Anne Ulinski
Assessing potential social consequences of deer management in Cuyahoga Valley
By Kevin L. Skerl
“Flightlines”: Developing partnerships for migratory bird conservation in the North Cascades
By Robert C. Kuntz II
USGS science supports NPS in managing park resources
By John Dennis, Sharon Kliwinski, and Lindsay McClelland
Other Developments
USGS science helps protect Congaree Swamp
Effects of snowmobiles on wildlife
MGM2: Economic analysis for park-community planning
Process emerges for park vital signs water quality monitoring
Award-winner profiles - Weber and Finley honored for science-based management efforts
Ungulate management - Tule elk at Point Reyes
Technology in monitoring - Knowing where the falcons go
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By Annie Esperanza and Judy Rocchio
The landscape diversity of California includes remote, pristine views and large, rapidly developing urban areas such as the San Francisco Bay Area, the Los Angeles Basin, and the Central Valley. Its mostly Mediterranean climate helps make California one of the world’s most productive agricultural areas. Its population is the highest of all the states, made up of millions of people who drive vehicles. All of these factors contribute to levels of air pollution that adversely affect human health and the natural resources found within airsheds of several California Class I national parks. Class I areas, as defined in the Clean Air Act, include national parks greater than 6,000 acres and national wilderness areas greater than 5,000 acres that were in existence before August 1977. Class I areas are given the most stringent protection under the act.
Class I national parks in California experience some of the best and worst air quality found in any park area in the country. Low levels of air pollutants are more common in coastal area parks, such as Redwood National Park and Point Reyes National Seashore, and parks far from urban areas, like Lava Beds National Monument. In the Sierra Nevada, cleaner air is evident to the north at Lassen Volcanic National Park but then degrades toward Yosemite, with the highest levels of air pollutants in the Sierra found south of Yosemite in Sequoia and Kings Canyon National Parks. Urban areas produce pollutants, which are then transported via air currents to downwind park areas, such as Sequoia and Kings Canyon National Parks, Joshua Tree National Park, and Pinnacles National Monument.
In April 2001, under contract to the Air Resources Division of the National Park Service, Tim Sullivan (E&S Environmental Chemistry, Inc.), Dave Peterson (USGS Biological Resources Division), and Charlie Blanchard (EnvAir) completed the “Assessment of Air Quality and Air Pollutant Impacts in Class I National Parks of California.” This report summarizes current and potential air pollution conditions of nine Class I park areas in California, including Joshua Tree National Park, Lassen Volcanic National Park, Lava Beds National Monument, Pinnacles National Monument, Point Reyes National Seashore, Redwood National Park, Sequoia and Kings Canyon National Parks, and Yosemite National Park.
The report uses scientific information provided by research and monitoring of air quality effects in these nine parks to help park managers understand and address the effects of air pollutants on visibility and other components of natural ecosystems. Included in the investigations are terrestrial resource threats such as nitrogen and sulfur deposition and ozone exposure, aquatic resource threats like sulfur and nitrogen deposition, and visibility threats from particulates and aerosols.
This report supports the National Park Service’s mandate to protect air quality–related values in Class I areas by providing the following critical information: (1) a summary of terrestrial and aquatic systems for each Class I area; (2) a review of monitoring data for key pollutants; (3) a review of literature on ecological effects of air pollution; (4) an assessment of additional information needed to protect resources from air pollution; and (5) a park-specific assessment of pollution vulnerability. Although the science of monitoring air pollution and assessing associated biological effects is still evolving, park managers can now refer to a single document for the most recent information regarding air pollution impacts on park resources. Copies of the report are available on the Web (www2.nature.nps.gov/ard/YearInReview/careview/).
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