Pollution of the air.
D000397:Air Pollution; D001991:Bronchitis / Q000209:etiology; D002249:Carbon Monoxide Poisoning / Q000453:epidemiology; D006801:Humans; D008131:London; D008854:Microscopy, Electron; D012905:Smog; D012906:Smoke
D012905:Smog; D012906:Smoke