Research Contracts

New Search

Project at a Glance

Project Status: complete

Title: Measurements of dry deposition parameters for the California acid deposition monitoring program

Principal Investigator / Author(s): Watson, John G

Contractor: Desert Research Institute and AtmAA, Inc.

Contract Number: A6-076-32

Topic Areas: Acid Deposition, Monitoring


The concentrations of acidic gases and particles are measured at 10 sites throughout the State of California. Seven of these sampling sites represent urban areas (South Coast Air Basin, San Francisco Bay Area, Bakersfield, Santa Barbara and Sacramento) and three represent forested areas (Sequoia, Yosemite, and Redwood National Parks). Several of these sampling sites are collocated with sites, which are part of other air quality compliance and forest response monitoring networks. Hourly average values for ozone, wind speed, wind direction, atmospheric stability, temperature, dew point, time of wetness and solar radiation are obtained from continuous monitors, Daytime and nighttime measurements are taken every sixth day for sulfur dioxide, ammonia, nitrogen dioxide, and nitric acid gases on absorbing substrates. Mass, sulfate, nitrate, chloride, ammonium, sodium, magnesium, potassium and calcium ion measurements are made on filter samples of particles in the PM and PM size ranges. The substrate-based measurements are taken following the EPA and ARB regulatory sampling schedules for suspended particulate matter. Weekly average wet deposition samples are taken at or near the dry deposition sampling sites. The first year of the routine monitoring program included installation of the network, training of technicians, acquisition and validation of data and transfer of the sampling and analysis technology to Air Resources Board (ARB) operating divisions. Data have been validated and catalogued for the period May 1988 through September 1989.


For questions regarding this research project, including available data and progress status, contact: Research Division staff at (916) 445-0753

Stay involved, sign up with CARB's Research Email Distribution List