Ozone exposure and blood antioxidants: A study in a periurban area in Southern France

Major carotenoids in plasma-especially beta-caarotene-are affected by oxida tive 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 control ling for other determinants, the impact of personal ozone exposure on carot enoids levels in plasma. During the summer, we recruited 58 volunteer subje cts 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 t his period, we assessed plasma antioxidants. We observed a negative signifi cant regression coefficient between (alpha- or beta-carotene and ozone expo sure (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 me dian intake value (i.e., 6.6 mg/d) of the overall group, we noted that a re latively low exposure to ozone (greater than or equal to 50 mu g/m(3).h or greater than or equal to 23.8 ppb) induced a significant decrease in plasma beta-carotene levels (i.e., 0.7 mu mol/l to 0.4 mu mol/l). This significan t 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.