Total personal exposure to fine particulate matter in an urban adult population:: the role of ambient air and transport

The objectives of this study were to evaluate the total personal exposure to fine particulate matter (PM 2.5 mu m) of an urban adult population and to estimate the fraction of this exposure associated with ambient air and with traffic exhausts. Portable monitors were used to evaluate exposure; these results are compared with fixed ambient air measurements. Forty volunteers, scattered across the Grenoble metropolitan area and commuting by various means, were followed during the summer of 1996 for 48 hours. They carried a case containing two PM 2.5 personal monitors and filled in time-activity diaries as well as life environment questionnaires. The average total PM 2.5 mass collected over 48 h. was 104 mu g; 33% of this mass was attributable to ambient air, and time spent outdoors was only to 11% of the total. These data will allow the contribution of urban traffic to total and ambient air PM 2.5 exposures to be evaluated.