The proportion of Americans, or more than 137 million people, who live in areas with poor air quality, according to a new report. Only one of the top 25 worst cities with particulate matter pollution was east of the Rocky Mountains and California had 11 of the top 25 polluted cities. Fresno, Calif., had the worst short-term particulate matter pollution and Los Angeles had the worst ozone levels. People of color were almost four times more likely to live in a county with poor air quality compared to white people.
