Bay Area declared one of country’s smoggiest regions

The American Lung Association (ALA), a health organization based in Chicago, released its annual State of the Air report and rankings of America’s smoggiest cities this week. Its findings revealed that the Bay Area ranks as one of the country’s most troubled locales for air quality.

ALA lumps nearly the entire Bay Area together in its rankings, placing a joint San Francisco-Oakland-San Jose designation in eighth place for ozone pollution, sixth place for “year-round particle pollution,” and fourth place for “short-term particle pollution.”

Southern California locations, like Los Angeles and Bakersfield, ranked first in all categories except for year-round particle pollution, in which Fresno took the unwanted top spot.

Short-term particle pollution rankings compare pollution levels across all regions on a single day. Year-round particle pollution represents the average exposure across an entire year.

The Bay Area’s bad marks seem surprising; San Francisco, in particular, usually enjoys sterling air quality.

Jenny Bard, a program director for ALA, tells Curbed SF that the rankings can be counterintuitive because of how the federal government defines regions.

“When we look at metro areas, these are what the [federal] Office of Management and Budget considers your metro area,” says Bard.

The federal government considers commute networks a big part of the definition of a metro region.

“They look at where people are coming from,” says Bard, explaining that “last October they added Stanislaus and Merced” to what’s designated the SF metro.

“That’s why the rankings jumped,” she adds.

Those communities used to be classified as part of the Central Valley, but now so many people are commuting from those counties—with their lower housing costs—to San Francisco instead that they’re effectively part of a huge, sprawling SF-centric zone.

On one hand, it may seem like this association is giving the Bay Area a bad rap. With the exception of certain bad days exacerbated by wildfires or heatwaves, our air quality is enviable.

But because of the way that SF’s economy now works, the Bay Area is by extension generating huge amounts of air pollution in other Northern California cities, and the rankings reflect that phenomena.

Note that this report covers a period from 2015 through 2017, meaning that these figures do not reflect the 2018 NorCal wildfires and their effect on SF’s direct air quality at the time.