The San Jose–San Francisco–Oakland metro area has been ranked among the worst in the U.S. for air pollution, according to the State of the Air report by the American Lung Association. The region is among the top 25 worst for ozone pollution and short-term particle pollution, largely due to wildfire smoke spikes. Despite this, the Bay Area is showing improvement, recording its lowest-ever level of particle pollution for the second consecutive year. About 44% of Americans live in counties with high levels of ozone or particle pollution.