New tool aims to pinpoint which cities have the worst air

A view of downtown Los Angeles,California is seen on a smoggy afternoon, 02 November 2006. Due to the city's geography making it susceptible to atmospheric inversion as well as the heavy reliance on automobiles as a major source of transportation, the city suffers from air pollution in the form of smog.

California's Environmental Protection Agency is rolling out a new tool on Tuesday, to help pinpoint communities that may be particularly vulnerable to pollution. It's the first environmental index of its kind in the nation, measuring a broad range of pollutants and health indicators in every zip code across the state.

California's Environmental Protection Agency is rolling out a new tool on Tuesday, to help pinpoint communities that may be particularly vulnerable to pollution. It's the first environmental index of its kind in the nation, measuring a broad range of pollutants and health indicators in every zip code across the state.

But the tool is already proving controversial, as the California Report's Central Valley Bureau Chief Sasha Khokha explains.