Aromatic DNA adduct levels were determined by the 32P-postlabelling assay in lymphocytes isolated from newspaper vendors working at urban high traffic areas (n = 31) and suburban low traffic areas (n = 22) in Milan, Italy. The DNA adduct levels ranged from 0.7 to 6.7/10(8) nucleotides, while most of them were between 1.0 and 3.0/10(8) nucleotides. No difference was found between the DNA adduct levels of the high-exposed group (2.2/10(8) and the low-exposed group (2.2/10(8). The heavy smokers (n = 8) had 23% higher DNA adduct level (2.7/10(8)) than the non-smokers (n = 37, 2.2/10(8) (P = 0.27), but no correlation was found between the adduct level and the number of cigarettes/day. Analysis of variance of the DNA adduct levels among the 14 pairs of individuals working at the same news-stands revealed little effect of the environmental air exposure on the DNA adduct level.