Predicting personal exposure of pregnant women to traffic-related air pollutants

As epidemiological studies report associations between ambient air pollution and adverse birth outcomes, it is important to understand determinants of exposures among pregnant women. We measured (48-h, personal exposure) and modeled (using outdoor ambient monitors and a traffic-based land-use regression model) NO, NO2, fine particle mass and absorbance in 62 non-smoking pregnant women in Vancouver, Canada on 1–3 occasions during pregnancy (total N=127).We developed predictive models for personalmeasurements using modeled ambient concentrations and individual determinants of exposure. Geometricmean exposures of personal sampleswere relatively low(GM(GSD)NO=37 ppb (2.0); NO2=17 ppb (1.6); ‘soot’, as filter absorbance=0.8 10−5m−1 (1.5); PM2.2=10 μgm−3 (1.6)). Having a gas stove (vs. electric stove) in the home was associated with exposure increases of 89% (NO), 44%(NO2), 20%(absorbance) and35%(fine PM). Interpolated concentrations fromoutdoor fixedsite monitors were associated with all personal exposures except NO2. Land-use regression model estimates of outdoor air pollution were associated with personal NO and NO2 only. The effects of outdoor air pollution on personal samples were consistent, with and without adjustment for other individual determinants (e.g. gas stove). These findings improve our understandingof sources of exposure to airpollutants amongpregnantwomenandsupport the use of outdoor concentration estimates as proxies for exposure in epidemiologic studies.