Beginnings of bronchitis.
D001991:Bronchitis / Q000209:etiology*; D002648:Child; D004785:Environmental Pollutants / Q000009:adverse effects; D004812:Epidemiologic Methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000150:complications; D012140:Respiratory Tract Diseases / Q000150:complications; D014028:Tobacco Smoke Pollution
D004785:Environmental Pollutants; D014028:Tobacco Smoke Pollution