Nitrogen dioxide and ozone exposures in a population sample from Ile-de-France

Background: Individual exposure to NO2 and O-3 has been estimated in an urb an population sample in southern France and the determinants identified. Th e present study was conducted to evaluated individual exposure to NO2 and O -3 and to identify the environmental determinants of exposure in a larger p opulation living in different environmental conditions. Methods: Two hundred ninety-four volunteers were recruited from the SUVIMAX sample in Ile-deFrance. The study covered 2 periods of 5 consecutive days, one in winter and rite other in the fall of 1998. Passive monitors were us ed to estimate individual exposure and indoor concentration at the particip ant's dwelling. Background atmosphere concentrations were obtained for the AIRPARIF surveillance network. Single and multiple ANOVA were used for stat istical analysis. Results: Individual exposures were low, especially for O-3 in the considere d periods of time. Mean NO2 and O-3 concentrations were 41 mu g/m(3)/h and 16 mu g/m(3)/h, respectively. The NO2 individual exposure increased with th e time spent in traffic and indoor concentration. The correlation coefficie nt between indoor and individual levels was r=0.73, and indoor concentratio n explained 50% of the variance in individual exposure. The sire of the dwe lling with regard to high traffic street, and most strongly the presence of a gas stove influenced indoor concentration. However, mechanical air extra ction decreased the mean indoor NO2 level of the dwellings. Conclusion: This study allowed identification of the environmental determin ants of NO2 exposure in an urban sample. These data, together with those ob tained previously, well be used to establish an exposure matrix for NO2.