Regions to Be Accountable for Their Traveling Smog : Environment: Downwind areas won’t be held responsible for pollution they inherit, state panel decides.

To find a more equitable way to measure whose smog is whose, the state Air Resources Board approved a policy resolution Friday that will hold regions accountable for the air pollution they generate, even after the smog has traveled miles from home.

Beginning immediately, the state will no longer hold downwind areas, such as San Diego and the San Joaquin Valley, responsible for the smog they inherit from upwind neighbors such as Los Angeles and San Francisco.

Instead, the resolution urges air quality districts that significantly harm their neighbors’ air quality to develop strategies to reduce transport smog.

Jerry Martin, a spokesman for the state board, said the state’s 41 air quality districts will now consider the board’s resolution and begin developing strategies. Friday’s action reaffirms a portion of the California Clean Air Act that requires regions to take their neighbors into consideration when implementing smog-reducing regulations. In the act, regional districts are asked to be good neighbors and impose extra controls, if necessary, to keep their pollution out of someone else’s back yard.

Bob Goggin, a spokesman for the San Diego County Air Pollution Control District, called the policy “significant” because it will clarify “who is responsible for what.” By the district’s own measure, 41 of the 55 days that San Diego County exceeded federal air quality standards in 1989 were caused by smog from Los Angeles. Of the 158 days that San Diego exceeded state standards, Goggin estimated 62 could be blamed on Los Angeles.

Under the policy, smoggy San Diego days judged to be caused by Los Angeles smog would not be counted as days that San Diego exceeded air quality standards. The result would put less pressure on San Diego County to impose stricter smog-control measures.

Although the pollution on those days would be racked up to Los Angeles, it also is unlikely that the new policy would mean stricter standards in that area, Goggin said. Los Angeles already has the strictest air quality plan in the nation, he said.

“They’re already doing what they can. They’re not going to make their plan any tougher,” Goggin said. “The policy just recognizes that they have the responsibility.”

The resolution, which specifies 14 sites around the state where boundary-crossing smog has been identified as a significant source of air pollution, likely will have a greater impact on areas that have not yet completed their air quality plans or areas where transport smog is responsible for the vast majority of smoggy days.

Martin said San Luis Obispo County, for example, which never violates federal standards and only rarely exceeds stricter state limits, could benefit greatly if its neighbors adopted stricter control measures.

The problem goes far beyond San Diego. San Bernardino, Riverside and Palm Springs have all inherited pollution generated in Los Angeles County. Los Angeles smog has been measured by scientists at Death Valley and the Grand Canyon. One study spotted California smog as far away as Colorado.