Life in America’s most polluted city

Every night, not long after the sun drops below the dusty horizon on the outskirts of Bakersfield, Jesus Alonso begins the ritual of safely putting his 8-year-old son, also named Jesus, to bed.

In the same home he grew up in, in the same bedroom where he slept throughout his own adolescence, the older Jesus goes to his child’s bedside and sets him at a 45-degree angle, so his head is elevated, to help him breathe, and always on his side — in case he throws up in his sleep. He puts a bucket beside the mattress for the same reason. A freshly cleaned and refilled humidifier infused with a liquid cough suppressant exhales camphor- and menthol-scented mist. Jesus aims an air purifier at his son’s bed, but not directly; the air is angled to blow onto him from off the wall so it works without hitting him too hard. Jesus developed this routine out of desperation. It’s the only measure — despite dozens of medications and doctor visits — that seems to work...