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Valley air remains among worst in nation
State of Air graphic

Stanislaus County received a big red “F” on its report card in the American Lung Association’s State of the Air 2022 report. The region is also ranked amongst the most polluted in the country.

The San Jose-San Francisco-Oakland region — which includes all of Stanislaus County — made the top 5 list for worst air quality in the nation in the year-round particle pollution and short-term particle pollution categories and in the top 15 list of worst regions for ozone.

Stanislaus County had 51 unhealthy air days for sensitive groups and four unhealthy for everyone days between 2018 and 2020 because of ozone pollution and 40 unhealthy days for sensitive groups and 26 for everyone for short-term pollution, earning an F grade in both categories from the American Lung Association.

The San Jose-San Francisco-Oakland region ranked fourth in the nation as the worst for both year-round particle pollution and short-term particle pollution and 13th for high ozone days.

It’s not just the San Jose-San Francisco-Oakland area that is falling short in air quality, according to the report, all eight counties in the San Joaquin Valley received failing grades.

The “State of the Air” 2022 report finds that despite decades of progress on cleaning up sources of air pollution, more than 40% of Americans—over 137 million people—are living in places with failing grades for unhealthy levels of particle pollution or ozone. This is 2.1 million more people breathing unhealthy air compared to last year’s report. Nearly 9 million more people were impacted by daily spikes in deadly particle pollution than reported last year. In the three years covered by this report, Americans experienced more days of “very unhealthy” and “hazardous” air quality than ever before in the two-decade history of “State of the Air." 

“‘State of the Air 2022’ shows that an unacceptable number of Americans are still living in areas with poor air quality that could impact their health,” said Harold Wimmer, National President and CEO of the American Lung Association. “More than 137 million Americans live in counties that had unhealthy levels of particle pollution or ozone. In addition, communities of color are disproportionately exposed to unhealthy air. The report found that people of color were 61% more likely than white people to live in a county with a failing grade for at least one pollutant, and 3.6 times as likely to live in a county with a failing grade for all three pollutants.”

The Lung Association’s annual air quality “report card” tracks and grades Americans’ exposure to unhealthy levels of short-term spikes in particle pollution (also known as soot), annual particle pollution and ground-level ozone air pollution (also known as smog) over a three-year period. This year’s report covers 2018-2020.

The report continues to show long-term improvement in the nation’s air quality thanks to decades of work to reduce emissions. However, this has been offset in part by the negative impacts of hotter, drier conditions caused by climate change. Wildfires in the western U.S. were responsible for a sharp rise in particle pollution spikes in several states.

Learn more about California’s grades including local air quality data for each county and metropolitan area at