Ozone Exposure and Blood Antioxidants: A Study in a Periurban Area in Southern France

Abstract

Major carotenoids in plasma–especially β-carotene–are affected by oxidative stress (e.g., tobacco smoking). Environmental ozone induced oxidative stress in experimental in vitro and in vivo studies, and it also increased the incidence of lung cancer in mice. We proposed to measure, after controlling for other determinants, the impact of personal ozone exposure on carotenoids levels in plasma. During the summer, we recruited 58 volunteer subjects who worked in a periurban zone. We asked each subject to wear a passive sample, which measured ozone exposure for 5 consecutive d. At the end of this period, we assessed plasma antioxidants. We observed a negative significant regression coefficient between α- or β-carotene and ozone exposure (r = -.39, p < .01, and r = -.45, p = .02, respectively). In a subsample of 45 nonsmoker subjects, among whom carotene intake was lower than the median intake value (i.e., 6.6 mg/d) of the overall group, we noted that a relatively low exposure to ozone (≥ 50 μg/m³ · h or ≥ 23.8 ppb) induced a significant decrease in plasma β-carotene levels (i.e., 0.7 μmol/l to 0.4 μmol/l). This significant decrease suggested that a high dietary intake of fruit or vegetables can have a beneficial influence on the levels of plasma antioxidants generated in response to ozone exposure.