Quietly, while no one seemed to be paying much attention, the Central Valley has become one of the smoggiest places in the nation. Kern, Fresno and Tulare counties rank third, fourth and fifth among those counties that exceeded federal ozone standards the most days from 1997 to 1999, according to the American Lung Association's 2001 State of the Air report. While car-crazy Los Angeles is most often associated with oddly orange skies, in truth, Los Angeles's reign as smog king is over. Today, it ranks a mere eighth on the list of America's 25 most ozone-polluted counties. The top two counties are San Bernardino and Riverside, whose western ends are intensely urbanized and industrial. But the next three counties on the list — Kern, Fresno and Tulare — are in a region more commonly associated with cotton and tomatoes than with third-stage alerts and respiratory distress. Cleaning up the valley's air is a tough challenge. Unlike many smoggy metropolitan areas, the ozone and particulate matter (soot and dust) contaminating Central Valley air do not typically emanate from large stationary sources such as factories and power plants. The pollution, instead, is the product of millions of small sources, many of them mobile, such as cars, and farm and construction equipment. Moreover, farming — the top source of valley air pollution — remains unregulated and politically untouchable. Faced with this challenge, air-quality managers and health activists alike have settled on a clean-air strategy that, while guaranteed to be costly, is unlikely to do much in the short term to make the valley's air more breathable: lawsuits. The most recent was filed in March, when the Sacramento Metropolitan Air Quality Management District (SMAQMD) sued the California Air Resources Board (CARB) over its failure to require the more rigorous Smog Check II vehicle emissions tests for cars and trucks in the San Francisco Bay Area. Autos statewide are required to undergo basic idling-engine smog tests every two years, but those in particularly polluted areas are also required to pass a more rigorous test that monitors the vehicle under a variety of engine speeds. The Bay Area is exempt from that program. In its suit, SMAQMD contends that the exemption is unfair and illegal. The federal Environmental Protection Agency (EPA) has designated the six-county Sacramento region a "severe nonattainment" area for ozone under the Clean Air Act. By law, SMAQMD argues, the CARB is required to reduce migrating Bay Area smog because the board concluded in 1993 that wind-blown pollutants contribute significantly to Sacramento's violation of the federal standards. The SMAQMD lawsuit is but the latest domino to fall. In February, the San Joaquin Valley Air District (SJVAD) also sued CARB, seeking a crackdown on smog getting blown into the valley from the Bay Area and the Sacramento region. Like their counterparts in the Sacramento district, SJVAD regulators blame migrating emissions and the Bay Area's Smog Check II exemption for the valley's failure to comply with federal pollution standards. "The Valley Air District is employing every means at its disposal to control emissions originating locally," air pollution control officer David Crow said when announcing the lawsuit. "Ignoring the impact from the Bay Area is no longer an option." Additionally, Assemblyman Dennis Cardoza (D-Merced) has introduced AB 2637, which would impose the Smog Check II system on the Bay Area. However, catching a few thousand Bay Area automobiles that pass existing inspections but might fail the more rigorous Smog Check II program will not significantly affect air pollution in Kern, Fresno and Tulare counties. The SJVAD's lawyer admitted to a New York Times reporter last month that the Bay Area sends only 8 to 11 tons a day of nitrous oxide (NOX) — the primary constituent of ozone formation — into the San Joaquin region, while the valley needs to reduce its total NOX emissions by about 300 tons a day to comply with EPA regulations. But Crow's comment contains a kernel of truth, as revealed by yet another lawsuit over Central Valley smog. In early February, a coalition of environmental and public health groups sued the EPA for approving 34 local air district pollution plans in California. All those plans exempt agricultural operations from having to obtain air pollution permits because state law authorizes the exemption. "Giant farms," the plaintiffs assert, "are the San Joaquin Valley's largest source of air pollution, putting out more smog and soot than any other source, including cars, trucks, oil refineries or power plants." The exemption produces some noteworthy incongruities: diesel engines that power irrigation pumps are not required to meet emission standards; the same engines, if used in oil fields, must meet such standards. California's agricultural lobby has so far managed to fend off efforts to subject farm operations to the same air and water pollution rules applied to other industries, depriving the local air agency of a potent tool in its anti-smog campaign. Besides suing the state, the San Joaquin District is pursuing another paperwork strategy in reaction to its persistent smog problem: It has asked the EPA to change its nonattainment designation from "severe" to "extreme." In a fact sheet on this tactic, the district calls this a "bold step" but notes it could have a downside. "The valley would face the stigma of being the only other region besides the Los Angeles area to be classified as extreme," the fact sheet notes. "This could negatively impact economic development." Whether the step is bold is debatable. The changed status would simply give the district until 2010 to meet federal pollution standards. Its current deadline, which district officials acknowledge they probably cannot meet, is 2005. Missing the deadline could cost the region $2 billion in federal highway funds. As for the other impacts, public health advocates no doubt find it disingenuous, at best, for the district to warn of the negative impacts its smog strategy might have on economic development. A study published March 6 in the Journal of the American Medical Association demonstrated a conclusive link between exposure to fine particulate matter — such as dust blowing off farms and soot emitted by diesel irrigation pumps — and increased risk of death from lung cancer. That report followed one in issued in February by the University of Southern California demonstrating a connection between air pollution and childhood asthma. The California Department of Health Services says that 12,000 people are hospitalized for asthma each year in the San Joaquin Valley. More than 5,000 of them are children. Contacts: Dr. David Pepper, Medical Alliance for Healthy Air: (559) 459-5705. Brian Smith, Earthjustice: (415) 627-6700. California Air Resources Board: (916) 322-2990. San Joaquin Valley Air District: (559) 230-6000. Sacramento Metropolitan Air Quality Management District: (916) 874-4800. American Lung Association State of the Air Report: www.lungusa.org/air2001/