COMPARISON OF THE HEALTH-EFFECTS BETWEEN INDOOR AND OUTDOOR AIR-POLLUTION IN NORTHEASTERN JAPAN

In January-February 1984, more than 30000 inhabitants, aged 40 years or more, of three regions in the Miyagi prefecture, Japan, responded (response rate: 87%) to questionnaires on subjective symptoms (sixteen questions, including six on the respiratory system and three on the eyes) caused by the type of space heaters used at their homes, smoking habits, and location of their homes in relation to heavy traffic roads. Nonsmokers (2389 men and 10321 women, 12710 total) were selected for analysis. The analysis on the relationship between the type of heaters and ophthalmo-respiratory subjective symptoms showed that one symptom in men and two symptoms in women were significantly more prevalent among those who use indoor air-polluting heaters (e.g., unvented kerosene/gas stoves) than those who use nonpolluting ones (e.g., vented heaters). When the relationship of home location and symptom prevalence was similarly examined, those in homes located at heavy traffic roads had more symptoms (three and seven symptoms among men and women, respectively) than those in homes which were not at heavy traffic roads. The comparison in the numbers of symptoms (with a significant increase in prevalence) between those associated with indoor pollution and that with outdoor pollution suggests that the effects of indoor pollution caused by pollutant-emitting heaters are less intensive than the effects of outdoor pollution by traffic.