Cities: Western Wind, When Wilt Thou Blow?

From above, it looked like a dirty blanket enfolding the whole northeast. Pilots dipping from crystalline skies prepared abruptly to make instrument landings. In midmorning, motorists inched through the Stygian haze with smarting eyes and headlights ablaze. Skyscrapers were amputated at the midriff. Pedestrians in city streets gasped at the miasmal murk even as newspaper headlines screamed that their next breath might be a dose of poison.

From Boston to Baltimore, smog's grey, grimy pall settled in for three days and nights, frightening residents with the specter of killer fogs such as...