California Air Resources Board

SACRAMENTO –  The California Environmental Protection Agency's (Cal/EPA) Air Resources Board (ARB) today launched a four-month, multi-million dollar study of smog in Southern California.

        "Smog remains a serious environmental challenge in the Southern California air basin and its impact on its neighboring states and Mexico. This study utilizes sophisticated technology that will improve our understanding of how smog is formed and how it moves from one region of Southern California to another," Acting Secretary for Environmental Protection Peter Rooney said. "While information from this study will be used to reduce smog and protect public health in Southern California, the study's data will also prove valuable to other states and ultimately to other nations around the world as they battle air pollution," Rooney added.

        The $5 million Southern California Ozone Study 1997 (SCOS97) will stretch over all of Southern California, from San Luis Obispo and Kern counties into the northern fringe of Mexico, and from the Pacific Ocean to the Arizona-Nevada border, an area of approximately 55,000 square miles. It will last from June 15 to October 15.

        The study will focus on ozone, the eye-stinging, lung-damaging pollutant that is one of the major constituents of smog. Ozone continues to be a troublesome problem despite major reductions in southland smog through Cal/EPA-sponsored programs, along with work by local air districts and industry Cleaner vehicles, cleaner gasoline and diesel fuel, and industrial emission controls reduced average exposure to ozone in the greater Los Angeles area by 80 percent between 1981 and 1995. But the region's air still contains the highest ozone levels in the United States, and winds transport ozone from Los Angeles to other areas of Southern California.

        The SCOS97 researchers will focus particularly on ozone formation up to two miles above ground level, since information on air quality and meteorological conditions aloft were not the main focus of previous Southern California smog studies. The researchers will also try to quantify the amount of hydrocarbons and nitrogen oxides (the two main contributors to ozone) coming from sources such as motor vehicles, airplanes, ships, factories, power plants, oil refineries and even from various types of vegetation.

        Data gathered will be used to gain a better understanding of how ozone is formed and how it moves from one area to another. Ultimately, this information will be used to devise more precise and effective measures to reduce ozone in Southern California.

        Daily ozone readings will be taken from a network of more than 100 air monitoring stations that already exist across Southern California. Approximately 30 new monitoring stations will be added during the study to gather more information on air movement, and ozone.

        An equipment-packed trailer at the El Monte Airport, operated by the National Oceanic and Atmospheric Administration, will send laser beams into the air as part of a lidar system to measure ozone concentrations up to 10,000 feet. Lidar is similar to radar but uses laser beams rather than radio waves. The absorption of particular wave lengths of light will show the location and amount of ozone aloft. "This lidar system is particularly important because it provides a continuous picture of ozone formation and movement in the heart of the study area," ARB Chairman John Dunlap said.

        SCOS97 staff will also set up a network of radar wind profilers -- ground radar units that measure wind speed and direction. The radar units will also take temperature readings.

        Other equipment to be used includes more than 1,000 weather balloons that will be launched from 17 sites over the life of the study and six airplanes that will take air samples, read temperatures and track air movement. The airplanes and weather balloons will be used extensively to take readings on 15 days when ozone readings are high.

        "Tracking air movement is a major part of the study because Southern California's complex geography of oceans, deserts, mountains and valleys create some of the most complex wind-flow patterns in the world," Dunlap said. Some of the equipment, Dunlap noted, will even measure the amount of sunlight hitting the ground. (Sunlight reacting with air pollutants is one of the main factors in the creation of smog. )

        Participating in the study with ARB are the Mojave Desert, San Diego County, Santa Barbara County, South Coast, and Ventura County air districts; the U.S. Environmental Protection Agency, U.S. Navy, the Coordinating Research Council (a research arm of the auto and oil industries) and NARSTO, a composite organization of approximately 100 government, industry and academic organizations from Canada, Mexico and the United States. NARSTO's main mission is determining ways to control ozone in the lower atmosphere.