Atmospheric pollution represents a relevant environ-and smoking habits) not exposed to traffic pollutmental hazard which has been associated with con-ants. The aim of this study was to assess the cytogesiderable excess mortality, morbidity, and in-netic effects, such as micronucleus frequency in pecreased rates of respiratory diseases in humans. ripheral blood lymphocytes, and to estimate the To date, more than 3,000 environmental chemical association with individual exposure to PAH. Statiscompounds have been identified in the ambient at-tical analysis of the frequency of micronuclei in binumosphere, including a variety of mutagenic and/ cleated cells showed higher mean levels in referent or carcinogenic agents, such as polycyclic aromatic subjects (4.03%) than in traffic police officers hydrocarbons (PAHs), aromatic amines, and het-(3.73%). Smoking showed no effect on the freerocyclic compounds. Positive associations be-quency of micronuclei. The study failed to detect tween cytogenetic markers and airborne levels of any association between micronucleus frequency PAHs have been reported by experimental and hu-and individual level of benzo(a)pyrene, considered man studies. Traffic has been implicated as the ma-a marker of exposure to PAHs. These findings indijor determinant for the concentration of PAHs and, cate that exposure to urban air pollutants does not therefore, for the genotoxic activity of urban air. A result in increased levels of micronuclei in periphbiomonitoring study has been conducted in 82 Ital-eral white blood cells. Environ.