According to his death certificate, Devra Davis’ uncle died of a heart attack. But in the book When Smoke Ran Like Water, Davis, an epidemiologist, provides a more compelling explanation for why Uncle Len died suddenly at the age of 50 during his daily game of handball: He had sucked in too much of Southern California’s lethal air. “Pollution itself never shows up on death certificates,” writes Davis. “With rare exceptions, the diseases worsened by bad air are among the most common afflictions in the modern world: heart disease, cancer, and asthma.” Reading about public health statistics, on the other hand, can only bore you to death. Luckily for her readers, Davis is no dullard. Throughout the book, she breathes life into such potentially suffocating subjects as global warming and the dangers of lead poisoning, distilling each epidemiologic trend into a personal tale of tragedy, often involving members of her own family. She’s in town at 7 p.m. at Politics and Prose, 5015 Connecticut Ave. NW. Free. (202) 364-1919. (Felix Gillette)