Well, just a half mask, a green gauze mask, of the kind that medical workers wear. Not a full-face mask—that would be ridiculous. Even before the floods, landslides, and firestorms of the past several years, Luce (sometimes) wore a gauze mask. Not in public! Just at home. Especially from the south. There are industrial cities to the south. Her town, Hazelton-on-Hudson, is a hundred miles from New York City, and far fewer from the notorious power plant, with its majestic white plumes of poisonous smoke that are sometimes visible to those who search the sky with binoculars whenever there is an air-quality alert. This mask, acquired at a medical-supply store, Luce hurriedly removes if Andrew returns home unexpectedly, for her husband disapproves of what he calls her “overreacting” or “catastrophizing.” (Is that even a word—“catastrophizing”? Luce understands that Andrew means to affect a comical tone, a sort of cartoon rhetoric, to soften the mockery and the annoyance he so clearly feels; yet “catastrophizing” also acknowledges the very real, the surely imminent catastrophe.) Today, Luce is not wearing the mask, though the wind from the south does indeed smell funny, wrong. And th...