Move over, Los Angeles: The Nation's Worst Air Has Shifted from City to Farms. (Lay of the Land)

Article excerpt

In satellite photographs, the `Los Angeles basin looks a little hazy, but California's much less populated San Joaquin Valley (the southern portion of the great central valley) is cloaked under a murky brown shroud. With its once-fresh country air now a serious health threat, the valley has just overtaken L.A. as having the nation's most frequently dirty skies.

Valley dwellers not only see the junk, they feel it: A study by the Center for Health Policy Research at the University of California, Los Angeles, finds that asthma rates for the valley's Fresno County are almost twice as high as those for residents of LA County. Yet while eyes burn and lungs ache in the state's 240-mile-long agricultural midsection, it has taken citizen action to force local and federal agencies to do their job.

Home to nearly 3.5 million people and a half-million cows, the trough-like valley traps vehicle exhaust as well as pollution from the oil refineries in its westside foothills and from its myriad farms and dairies. A combination of pesticide spraying, heavy-duty diesel equipment, dust stirred up during tilling and harvest, and ammonia and particulate matter from livestock waste makes industrial agriculture the region's biggest polluter. Part of the reason is that the EPA has exempted California farms and dairies from federal pollution rules. …