A five-year prospective field study of early obstructive airway disease.
D000397:Air Pollution; D001991:Bronchitis / Q000209:etiology*; D002908:Chronic Disease; D006801:Humans; D008131:London; D009093:Mucus / Q000378:metabolism; D011446:Prospective Studies; D011656:Pulmonary Emphysema / Q000209:etiology; D012907:Smoking; D013147:Spirometry; D013183:Sputum