Personal Exposure to Nitrogen Dioxide Pollution and Effect on Plasma Antioxidants

ABSTRACT

We conducted a cross-sectional epidemiological study to evaluate personal exposure to nitrogen dioxide and its effect on blood antioxidants. Personal exposure of 107 volunteers was assessed for 14 d with passive monitors. We excluded heavy smokers (>10 cigarettes/d) from the study. Sociodemographic and environmental data, as well as βcarotene intake, were recorded. We mainly attributed the mean nitrogen dioxide personal exposure (31.9 ± 12.7 μg/m³ [0.017 ppm or 0.70 μM/m³]) (R² = 0.75) to residence site in the city, time spent in urban traffic, and use of gas stoves. The correlation between nitrogen dioxide exposure and blood antioxidant concentration was weak; in addition, the correlation coefficients for men and women were inconsistent. Nonetheless, we found some evidence of an interaction between carotene intake and nitrogen dioxide exposure: a significantly lower plasma (β-carotene level was evident among subjects who consumed ≤ 4.5 mg/jour of carotene and who were exposed to nitrogen dioxide levels that exceeded 40 μg/m³ (0.021 ppm or 0.87 μM/m³) of nitrogen dioxide.