Personal exposure to nitrogen dioxide pollution and effect on plasma antioxidants

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 time study, Sociodemographic and environmental data, as well as beta-carotene intake, were recorded, We mainly attributed the mean nitrogen dioxide personal exposure (31.9 +/- 12.7 mu g/m(3) [0.017 ppm or 0.70 mu M.m(3)]) (R-2 = 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 beta-carotene level was evident among subjects who consumed less than or equal to 4.5 mg/jour of carotene and who were exposed to nitrogen dioxide levels that exceeded 40 mu g/m(3) (0.021 ppm or 0.87 mu M/m(3)) of nitrogen dioxide.