Chronic pulmonary effects of volcanic ash: an epidemiologic study.

The chronic pulmonary effects of exposure to volcanic ash were investigated by conducting a cross-sectional epidemiological study of 2,006 women between 30 and 59 yr of age who lived in three areas subjected to different levels of airborne ash. In the three areas prevalences of chronic bronchitis and other respiratory symptoms were so low that volcanic ash did not seem to be a major cause of respiratory disease. In the highly exposed area, however, 9.9% of the women experienced symptoms of one or more respiratory diseases, while 6.4% of the women in the medium- and 5.4% of the women in the low-exposure area had these symptoms. Prevalences of each disease and symptom increased as total suspended particulate level increased, suggestive of an association of mild respiratory symptoms with volcanic ash.