An epidemiologic study on 94 traffic police officers exposed to airborne polycyclic aromatic hydrocarbons (PAH) and 52 age-matched urban residents working in confined spaces considered as referent subjects without occupational exposure to PAH was conducted to characterize individual exposure to benzo(a)pyrene (BaP), benzo(b)-, and benzo(k)fluoranthene (BbF and BkF) and the occurrence of DNA adducts and micronuclei in white blood cells (WBC). The study's findings indicated that mean concentrations of PAH in the city air were 10 to 30 times higher among the traffic police officers compared with referent subjects (4.55 +/- 3.44 ng/m3 and 0.15 +/- 0.30 ng/m3 of BaP among police officers and referents, respectively). 32P-postlabeling DNA adducts in WBC obtained from police officers (1.48 +/- 1.35 RAL/10(8)) were significantly higher than in referent subjects (1.01 +/- 0.63 RAL/10(8), P = 0.007), suggesting a possible role of exposure to airborne PAH in the DNA damage. The frequency of micronuclei was significantly increased (P = 0.02) in referent subjects (4.49 +/- 2.0% cells) compared with police officers (3.75 +/- 1.65% cells) due to the large proportion of females in the former group. Comparison of the mean micronuclei frequencies among 82 male police officers (3.73 +/- 1.6% cells) and referents (4.03 +/- 1.61% cells) failed to reveal a statistically significant difference (P = 0.38). Our findings support the evidence of a noxious effect of the exposure to airborne PAH found in large cities on the occurrence of DNA adducts in WBC, whereas there seems to be no effect on the cytogenetic risk assessed as micronuclei frequency.