Time spent in the home by different family members

The study objective was to assess the length of time spent inside the home for each family member in a sample population in the southwest of England. Such information is vital in any study concerned with exposure to pollutants in the home environment, in order to calculate a dose response for a specific health effect in the individual. The design was a longitudinal observational study which started in pregnancy and was carried out for one week in each month over a 12 month period. The setting was a sample of 170 families within the Avon Longitudinal Study of pregnancy and Childhood (ALSPAC) where indoor air pollutants were being measured. The number of hours spent in the home each day for each family member was obtained from self-report using weekly diary sheets. The results indicated that mothers, fathers and young infants spent an average of 18.4 (76.7%), 14.7 (61.3%) and 19.3 (80.4%) hours per day, respectively, in the home, In winter, infants spent longer in the home than in the summer months. At weekends, the amount of time spent at home by the father increased, but that of the mother and infant decreased. The results emphasize the importance of assessing duration of exposure in any study concerned with the health effects of air pollution.