Environmental tobacco smoke exposure patterns: a subanalysis of the Canadian Human Time-Activity Pattern Survey.

This subanalysis of the Canadian Human Activity Pattern Survey examines environmental tobacco smoke (ETS) exposure in non-smoking respondents relative to age, sex, socioeconomic status and prevalence of asthma. 2,381 respondents (response rate 64.5%) from Toronto, Vancouver, Edmonton and Saint John completed a 24-hour recall time-activity diary. For each activity and location, respondents were asked, "was there any smoking during the activity?" Among non-smoking adults, youth, children and asthmatics, the rates of ETS exposure were 32%, 34%, 30% and 42% respectively. Regarding the location of exposure, adults reported ETS exposure in various locations (work, bars and restaurants), including home. Children experienced the most exposure at home, primarily between 4 p.m. and midnight. Adults reported ETS mainly in the living room (16%) and vehicles (13%); for children, the living room (22%) and the bedroom (13%) were the most common locations. Determining characteristic time and location patterns for ETS exposure underpins educational strategies to help non-smokers avoid ETS exposure.