Research Projects

Project at a Glance

Project Status: complete

Title: Monitoring of atmospheric particles and ozone in Sequoia National Park

Principal Investigator / Author(s): Cahill, Thomas A

Contractor: Air Quality Group, Crocker Nuclear Laboratory, University of California, Davis

Contract Number: A5-180-32

Research Program Area: Atmospheric Processes


The report describes a three-year project (1985-87) conducted by the Air Quality Group of Crocker Nuclear Laboratory to monitor atmospheric particles and ozone in Sequoia National Park, as part of an attempt to understand the impact of acid deposition and other air pollutants on the park's ecosystem.

The project undertook extensive measurements of particulate matter, which were then correlated with meteorology, known elemental sources, and wet and dry deposition. For high-altitude ozone measurement, the project developed a new solar-powered ozone monitoring system.

After background discussion of the air pollution meteorology of Sequoia and the surrounding area, the report discusses first atmospheric particle monitoring and then ozone monitoring, along with the results of each.

The results show that particulate matter at Sequoia is similar to that present at other sites on the western slope of the Sierra Nevada range at equivalent elevations, although some anthropogenic species including nickel and sulfate are higher at Sequoia than at Yosemite National Park. The source of most of the particles is the San Joaquin Valley, with efficient transport by terrain-effect winds to elevations above 6,000 feet. By 10,000 feet, however, this transport is greatly weakened. The ozone profiles show a similar behavior with elevation. Daytime ozone levels at 6000 feet are equivalent to those on the valley floor, but decrease abruptly by 10,000 feet.


For questions regarding this research project, including available data and progress status, contact: Heather Choi at (916) 322-3893

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