Personal exposure levels of NO₂ for office workers and housewives living in Tokyo and neighboring prefectures were measured in four seasons with NO₂ filter badge.
NO₂ concentrations in indoor and outdoor air in their offices and houses were also measured in the same periods.
Personal exposure levels in winter ranged from 13 to 132 ppb and its distribution pattern was remarkably different from the other seasons. Furthermore, the mean value of the levels in winter (37.7 ppb) showed two times or more than those of the seasons (15.2-17.9 ppb). This fact suggests that use of heating apparatus affects largely NO₂ indoor air pollution in winter seasons. Actually, NO₂ exposure levels of subjects used kerosene heater (43.6 ppb) and gas heater (33.4 ppb) were higher than those of subjects unused heating apparatus (18.0 ppb). Personal exposure levels of NO₂ for man and woman living in the same houses were correlated well each other.
The time spent indoors for office workers and housewives were both longer than 22 hours a day. Home staying time was about 60% of total indoor staying time for office workers and 90% or more for housewives.
Personal exposure levels were significantly related to indoor exposure levels at home in all seasons, and at office and kitchen in spring. Furthermore, personal exposure levels could be estimated from NO₂ concentrations and staying times in various living environment.