Cytogenetic damage in buccal epithelia and peripheral lymphocytes of young healthy individuals exposed to ozone

Ozone (O-3) is an important component of air pollution and a potent oxidant of biomolecules. To address the hypothesis that elevated ambient O-3 can induce cytogenetic damage in healthy people, we collected buccal cells from two groups of students (N = 126) from University of California, Berkeley, in the spring and again in the fall. One group spent their summer in the Los Angeles (LA) area where summer O-3 concentrations are significantly higher than in the San Francisco Bay (SF) area, and another remained in SF. During the school year, all students were exposed to low O-3 levels in SF. The micronucleus assay in a total of 611 000 buccal cells demonstrated that, in the fall, micronuclei (MN) in normal cells for the LA group had increased 39% relative to levels in the spring (1.52 and 0.87 MN/1000 cells, respectively, P = 0.001). Students who spent the summer in SF had a 12.7% increase (P = 0.48). A similar effect of season was seen in degenerated buccal cells for the LA group (3.23 versus 1.88 MN/1000 cells, P = 0.003). LA but not SF subjects also had more degenerated cells in the fall sample (P = 0.003). These findings were paralleled by an increase in MN and nucleoplasmic bridges in lymphocytes and MN in buccal cells in a sub-group of 15 students who underwent a 4-h controlled exposure to 200 p.p.b. O-3. This cytogenetic evidence, along with recent studies linking O-3 exposure to elevated lung cancer risk and mortality, suggest potential public health implications from exposures to high oxidant environments.