Cleaner air in the Bay

The Bay Area is no longer on the list of the 25 most polluted areas in the nation, according to a recent American Lung Association report.

The study looked at particle and ozone pollution, noting that California in general has reduced car exhaust and soot immensely over the last decade, according to SFGate.com. Three of the nine least-smoggy counties in California are in the Bay Area, with San Francisco County ranking among the cleanest counties in the nation in terms of air quality.

Following the implementation of tight wood-burning regulations and California Air Resources Board greenhouse-gas emission standards, San Francisco County did not have a single day that exceeded federal ozone-pollution standards in 2011. Annual levels of Bay Area particulate pollution have declined between 15 and 30 percent every year since 2004.