Exposure to benzene in urban workers: environmental and biological monitoring of traYc police in Rome

Objectives—To evaluate the contribution of traYc fumes to exposure to benzene in urban workers, an investigation on personal exposure to benzene in traYc police from the city of Rome was carried out. Methods—The study was performed from December 1998 to June 1999. DiVusive Radiello personal samplers were used to measure external exposures to benzene and alkyl benzenes during the workshift in 139 policemen who controlled medium to high traYc areas and in 63 oYce police. Moreover, as biomarkers of internal exposure to benzene, blood benzene, and urinary trans, trans-muconic and S-phenyl mercapturic acids were measured at the beginning and at the end of the workshift in 124 traYc police and 58 oYce police. Results—Time weighted average (TWA) exposure to benzene was consistently higher among traYc police than among indoor workers (geometric mean 6.8 and 3.5 μg/m, respectively). Among the traYc police, the distribution of individual exposures was highly asymmetric, skewed toward higher values. Mean ambient benzene concentrations measured by municipal air monitoring stations during workshifts of traYc police were generally higher (geometric mean 12.6 μg/m) and did not correlat with personal exposure values. In particular, no association was found between highest personal exposure scores and environmental benzene concentrations. Among the exposure biomarkers investigated, only blood benzene correlated slightly with on-shift exposure to benzene, but significant increases in both urinary trans, trans-muconic and S-phenylmercapturic acids were found in active smokers compared with nonsmokers, irrespective of their job. Conclusion—The exposure to traYc fumes during working activities in medium to high traYc areas in Rome may give a relatively greater contribution to personal exposure to benzene than indoor sources present in confined environments. Smoking significantly contributed to internal exposure to benzene in both indoor and outdoor workers. (Occup Environ Med 2001;58:165–171)