Project at a Glance

Title: Crop loss from air pollutants assessment program. interim report

Principal Investigator / Author(s): Thompson, C. R.

Contractor: Statewide Air Pollution Research Center, University of California, Riverside

Contract Number: A5-031-33 & A4-088-33

Research Program Area: Ecosystem & Multimedia Effects

Topic Areas: Agriculture, Ecosystem Impacts


The Statewide Air Pollution Research Center (SAPRC) with funding by the California Air Resources Board (CARB) has developed a comprehensive program to assess the yield losses to California crops from air pollutants. Research during the past year has focused on preparation of a comprehensive assessment of yield losses to California Crops from ozone using 1984 as a target for analysis. A literature search indicated ozone dose-yield loss equations for 19 of the 52 crops in the California Agricultural Resources (CAR) Model. A crop data base was constructed containing crop yield, acreage, growing season, and location information by county and crop. An air monitoring data base was constructed containing hourly ozone data for each site in California, and dose information for air monitoring sites and time periods corresponding to the location and growing season of each crop in each county. Three ozone doses were calculated to correspond to growing season data required by the individual crop loss models: hours x pphm > 10 pphm, 7-hr seasonal average between 0900-1559 and 12-hour seasonal average between 0800-1959.

Nine crops were calculated to have losses of greater than or equal to 7% as compared to the potential yield at a background concentration of 2.5 pphm: alfalfa hay - 9%, dry beans - 23%, sweet corn - 7%, cotton - 20%, grapes - 21%, lemons - 28%, onions - 23%, oranges - 19%, and rice - 10%. Ten crops were calculated to have little yield loss (25%): barley - 0%, grain-corn - 2%, lettuce - 0%, corn silage - 5%, sorghum - 0%, spinach - 0%, strawberries - 0%, sugar beets - 0%, fresh tomatoes - 3%, processing tomatoes - 5%, and wheat - 2%. Of the remaining 33 crops in the data base 16 are at potential risk and 14 are not at risk from ozone as determined by the crops occurrence, or non-occurrence, respectively, in geographical areas where or seasons when ozone is > 5.0 pphm. Three "crops" are difficult to assess because they actually contain a large number of species: i.e., nursery, greenhouse and miscellaneous vegetable crops. The yield losses will be used for economic analysis by researchers at the University of California at Davis.

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

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