Personal measurement of exposure to black carbon and ultrafine particles in French schoolchildren

Abstract

Introduction Black carbon (BC) and ultrafine particles (UFP) are suspected to be damaging components of traffic related air pollution. However personal BC and UFP exposure in children is poorly documented. Our study aimed to measure these personal exposures in French children and quantify the contribution of different microenvironments (home, school, places of extra-scholar activities, transport) to their total exposure. Methods The study was conducted in 96 9-year-old children from a French birth cohort. BC and UFP were continuously measured by portable devices (microAeth® AE51 and DISCmini®) for a minimum of 24 hours. At the same time, participating families progressively filled in a space-time-activities budget questionnaire. The equivalent of one hour exposure (EHE) to BC and UFP was calculated by attended microenvironment. Results The children were more exposed to BC in trips and to UFP during indoor activities and in trips (see EHE in table). The most important UFP exposure peaks were recorded at home, especially during cooking. Home and school together accounted for much of the total exposure, 83.8% for BC and 85.3% for UFP. The contribution of transport to total exposure was 12.4% for BC and 9.7% for UFP, while extra-scholar activities were responsible for 3.8% and 5% of the total exposure to BC and UFP, respectively. Conclusion This study allowed to document for the first time in France the BC and UFP schoolchildren’s exposure in their daily lives. It showed levels varying widely between microenvironments, transport being responsible for the highest levels.