Helping crops breathe easier would generate about $120 million annually in net benefits for the San Joaquin Valley, according to three research economists. Richard E. Howitt, a professor of agricultural and resource economics at UC Davis, and his co-researchers conducted a study unusual because it considered the effects of ozone on agricultural production as well as human health to determine that the most economically efficient standard for ozone control is 0.14 to 0.12 parts per million. "Because plants dislike ozone as much as we do," Howitt says, "controlling ozone is not just good for human health, it's profitable in major agricultural areas." The San Joaquin Valley, which produces about 60 percent of the total value of state crops, has the second worst air quality in California with ozone concentrations exceeding the state standard of 0.09 ppm and sometimes reaching 0.17 ppm. High concentrations of ozone, which interfere with photosynthesis, can result in crop losses ranging from 8.4 percent for alfalfa hay to 32 percent for oranges, according to another study. The UC Davis study considered the costs of two different methods for controlling certain emissions that contribute to ozone pollution. Interestingly, the researchers found that the costs and benefits of achieving the federal ozone standard of 0.12 ppm vary by region. Only in the valley's central area of Fresno, Tulare, Madera and Kings counties did the benefits exceed the costs. The study was published in a recent issue of the Journal of Agricultural and Resource Economics. At the time of the study, co-authors Hong Jin Kim of the U.S. Environmental Protection Agency and associate professor Gloria E. Helfand of the University of Michigan were a graduate student and a faculty member, respectively, at UC Davis.