San Francisco, CA —

In a victory for clean air advocates and residents of California’s Central Valley, a federal appeals court on Friday January 20, rejected an inadequate ozone air pollution plan for the San Joaquin Valley. The court found the Environmental Protection Agency’s approval of the plan was arbitrary and capricious.

Thick layer of air pollution above the San Joaquin Valley, as viewed from Sequoia and Kings Canyon National Parks. (Richard Cain / NPS)

The San Joaquin Valley Air Pollution Control District adopted its plan in 2004 to meet federal limits on the maximum levels of harmful air pollution known as ozone or smog, that Central Valley residents can be exposed to in a one-hour period. EPA approved the 2004 plan in 2010, ignoring that fact that the plan was based on outdated air pollution data that the agencies knew to be incorrect.

Specifically, the 2004 plan was built on data from a model that estimated diesel truck air pollution emissions based on where trucks were registered, instead of where they actually drove. Before EPA approved the plan in 2010, that modeling defect had been fixed and the resulting emission projections were radically different. But EPA refused to consider this new information.

The court noted that, “The agency did not adequately address the staleness of its data and availability of more current data before reaching its conclusion.” Writing the opinion for the three-judge panel of the Ninth Circuit Court of Appeals, Judge Ronald M. Gould stated, “EPA knew that a new computer modeling tool was available and had access to data compiled through the use of the more current tool.” The ruling concluded, “We hold that EPA’s failure to even consider the new data and to provide an explanation for its choice rooted in the data presented was arbitrary and capricious.”

Paul Cort, attorney for the public interest law firm Earthjustice, which represented the Sierra Club and Medical Advocates for Healthy Air in the lawsuit, hailed the decision. “The court has ordered the Air Board and the EPA to stop playing legal games and come up with a proper plan to reduce air pollution in the real world. This is not just a paperwork exercise. The plan needs to address the real ozone levels in the Valley that are sending real people to the hospital.”

Kevin Hamilton, a registered respiratory therapist and founder of the group Medical Advocates for Healthy Air of Fresno, said, “As health practitioners we see first hand the effects of dirty air in the Valley. We must continue to hold these agencies accountable, to make sure that they obey the law and clean up our air.”

Gary Lasky, Vice Chair of the Tehipite Chapter of the Sierra Club, also applauded the court ruling. “Today’s decision is an important step toward cleaning the air in the Central Valley. We will be watching closely to see that EPA follows the court order and conducts a proper review of the plan. Only then can we actually start to see any improvement in air quality.”

Ozone, a major component of smog pollution, is a long-standing health threat across central California’s San Joaquin Valley. Of the ten U.S. cities with the worst air quality, four are in the San Joaquin Valley, according to the American Lung Association’s annual State of the Air report released in April of 2011.

Ozone is a toxic air pollutant formed by the chemical reaction between oxides of nitrogen and volatile organic compounds in the presence of sunlight. These compounds come from the exhaust of cars, trucks, construction and farm equipment, oil refineries, factories and other air pollution sources.

Ozone reacts with internal body tissues causing damage to lungs, exacerbation of asthma, reduction of lung capacity, increased respiratory-related hospital admissions, and even premature death. The health impacts are disproportionately felt by the most vulnerable—children, the elderly, and persons already suffering from respiratory ailments.

The one-hour ozone standard is aimed at limiting dangerous peaks in air pollution that are linked to spikes in emergency room visits and deaths. Congress amended the Clean Air Act in 1990, setting firm deadlines for meeting the 1-hour ozone pollution standard, and outlining the new minimum requirements for state and local air quality plans.