This story was originally published by CityLab and appears here as part of the Climate Desk collaboration. Until she moved to Fresno, California in 2003, Janet DietzKamei had never experienced asthma. But after just a few years in a city notorious for its filthy air—the American Lung Association lists it in the five worst US cities for air quality—DietzKamei found herself in the emergency room struggling to breathe. She soon started staying inside on days when the air was thick with smog from nearby industry or traffic, and would check the local air-quality alerts every morning.