First Evidence of Pollution Sullying Other Continents Scientists Document How a Chinese Dust Storm Affected Air Quality in North America. Research May Lead to Call for More Global Antipollution Efforts

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When the sky turned white last April, Thomas Cahill at the University of California at Davis knew the great Chinese dust cloud he was expecting had arrived. He and a number of other researchers had been following it through satellite data since it rose out of the Gobi Desert a few days earlier.

Their feat typifies how, for the first time, scientists are proving that pollution from one continent can affect air quality on another.

Riding a channel of air that forms under specific atmospheric conditions, Asian pollution can cross the Pacific Ocean in four to 10 days, adding to local pollution, says Dan Jaffe of the University of Washington at Bothell. While he adds that the pollution is usually very diluted by the time it reaches North America - and there is much more research to be done - the findings may add to the call for global pollution controls, as nations try to improve their air- quality standards. Dr. Jaffe says that the dust-cloud study and other research presented this week at a meeting in San Francisco of the American Geophysical Union represent the "first time anyone has {actually} documented" that pollution released on one continent can travel all the way to another continent. Giving an overview of the research at a press conference, Jaffe noted that Asian pollution occasionally has significant impact in North America. Fine particles settling out of the Chinese dust cloud raised pollution levels to two-thirds of the Environmental Protection Agency air-quality standard in a number of locations over the western United States. Jaffe added that even low levels of intercontinental contamination can enhance pollution from local sources. Asian pollution comes from many different sources. Some is desert dust. Some is industrial. Some is from pesticides. Jaffe and several colleagues found clear signs of industrial pollution in measurements taken March 29, 1997, at the Cheeka Peak Observatory in Washington. They found contamination from the burning of fuels, for example. Furthermore, extensive research into prevailing meteorological conditions show the pollution came from Asia, Jaffe says. …