"Pediatric asthma is common in Calipatria, where young athletes compete despite extreme heat and air pollution. "On a baseball diamond about five miles from the southeastern shores of California’s Salton Sea, 12-year-old Christopher Leon steps up to the plate. It’s a balmy spring evening in mid-April in Calipatria — population 6,012 — and, thankfully for these young athletes, there’s little wind. The nearby Salton Sea, a land-locked, saline lake, is drying, and gusty winds whip up toxic dust and particulate pollution from the exposed lakebed. Among the Calipatria Little League athletes, asthma and allergies are common.