Determinants of residential indoor and transportation activity times in Korea.

Information on time spent in microenvironments has a critical role for personal exposure to environmental pollutants. Unlike several large-scale studies in Western countries, no comprehensive research on time-activity patterns for exposure assessment has been conducted in Korea. We investigated determinants of residential indoor and transportation times of individuals over 10-years old in the Korean population. The population-based study collected time-activity patterns of 31,634 Koreans for two consecutive days. The residential indoor and transportation times were collected for a weekday and a weekend day. The impact of sociodemographic factors on time-activity was assessed using multiple linear regression models. The residential indoor times were 14.23 h for the weekday and 16.13 h for the weekend and shorter than those in Western countries. The transportation times were 1.75 h for the weekday and 1.68 h for the weekend day. The most significant factors in residential indoor time were employment status, age, monthly income, and gender for the weekday and employment status and gender for the weekend day. The factors in transportation were gender, employment status, and monthly income for the weekday and gender, employment status, age, and marriage status for the weekend day. Determinants of the time-activity pattern need to be taken into account in exposure assessment, epidemiological analyses, and exposure simulations, as well as in the development of preventive strategies. As Korean population activity patterns are substantially different from those in Western countries such as USA, Germany, and UK, this information could be critical for exposure assessment in Korea and other Asian countries.