Information about time spent in microenvironments plays a critical role in exposure assessment of the person concerned, considering that personal exposure relies on the characterization of time-activity patterns of the population at risk as human activities impact the timing, location, and level of personal pollutant exposure. The purpose of this paper was to present the time-activity patterns of Korean adults from a population-based study, and to determine the time spent each day in microenvironments. The population-based study collected time-activity data of about 46,000 adults for two consecutive days on weekdays (n=28,152) and weekends (n=18,800). The mean times spent at one’s own house, workplace or school, other’s house house, restaurant or bar, other places, and transportation related to the whole sample of 28,152 people were 14.90 hrs (62.08%), 4.28 hrs (17.81%), 0.24 hrs (1.01%), 0.51 hrs (2.14%), 2.45 hrs (10.21%), and 1.62 hrs (6.74%) on weekdays, respectively. Looking at the total time spent indoors by adults in different countries, the following four countries were ranked as follows, from lowest to highest: USA > Canada > Korea > Hong Kong. Due to cultural, socioeconomic and climatic differences, it may not be appropriate to directly apply statistical data of other countries to the Korean situation. This paper provides information on how the proportion of persons in different locations changes by time of day, on weekdays and weekends. Here, we can see that over 90% of respondents were in a residence from about 11 PM to 5 AM, and the largest proportion of respondents in workplaces or schools and other places is found between 8 AM and 5 PM.

The consumer products in the living environments include a variety of chemicals which could be harmful in the human health. The aim of this study was to assess the inhalation exposure and risk for cleaning workers who had used bleach in the university. A total of 81 cleaning workers took part in this study. Frequency and amount of cleaning bleach during working hours were investigated by questionnaire interviews. Exposure assessment was used by the exposure algorithm and exposure factors. Used cleaning bleaches were analyzed to identify the ingredients, and risk by exposure was assessed by separating as carcinogen and non-carcinogen substances. The results of chemical substances and the questionnaire were used to assess the exposure factors, and the inhalation doses were calculated through inhalation exposure algorithm. According to the questionnaires for the cleaning workers, frequence of cleaning bleach was 11.66 ± 7.21 times per month. And average usage time and amount per cleaning work were 30.78 ± 36.00 minute and 20099.53 ± 12998.60 mg, respectively. Risks for carcinogenic substances of formaldehyde, ethylbenzene, and chloroform were exceeded by 56.79%, 27.16%, and 82.72% as the reference value of 10−6, respectively.