Health effects of volcanic ash: a repeat study.

The Mount Sakurajima volcano in Kyushu, Japan, is proximal to a large residential area, and it emits an enormous amount of volcanic ash during frequent eruptions. In our previous study, we investigated, for the first time, respiratory effects of chronic exposure to volcanic ash. The study demonstrated a low prevalence of respiratory symptoms, even in the area of highest exposure; only a slight excess prevalence of symptoms appeared to be associated with exposure to volcanic ash. To confirm the findings of our previous study, the prevalence study of chronic respiratory symptoms for residents was repeated in Kanoya and Tashiro, which are located 25 and 50 km, respectively, from the crater of Mt. Sakurajima. The concentration of suspended particulate matter in Kanoya frequently exceeded the national environmental quality standards and, during summer and winter, was 2-3 times higher than that found in Tashiro. Women who were 30-59 y of age and who had resided in Kanoya or Tashiro for more than 3 y completed a modified ATS-DLD questionnaire. The prevalence of nonspecific respiratory disease was low, i.e., 6.5% in Kanoya and 6.2% in Tashiro; similar prevalences were found in women who had never smoked. When we restricted the analysis to individuals without a history of occupational exposure to dusts and who had no exposure to passive smoking, there was a slightly higher prevalence of nonspecific respiratory disease in Kanoya than Tashiro, but the difference was not significant. Eye symptoms were equally prevalent in the two areas.(ABSTRACT TRUNCATED AT 250 WORDS)