Exposure to air pollution in general population living in urban and rural environment: urinary benzene as biological index of exposure

Evidence is needed regarding air pollutant exposure in general population. One of the most important contributors to airurban pollution is benzene, a widespread air pollutant present both in outdoor and indoor environments, and a well knownhuman carcinogen. The aim of our study was to investigate the use of urinary (u) unmodified benzene (UB) as a biomarkerof air environmental pollution for general population. u-UB and u-cotinine were measured in urine samples of 243 Italianchildren (5-11 years) recruited in a cross-sectional study. Urine samples were collected at the end of the day, an analyticaldetermination of benzene was performed by solid-phase micro-extraction (SPME) - GC/MS. Analytical results werecompared with data obtained from questionnaires about participants' main potential exposure factors. The main findingswere that u-UB levels were influenced by secondhand smoke (SHS) exposure and urbanization of residence areas. Inaddition, data showed that, excluding children exposed to SHS, u-UB concentrations were about 2-fold higher in subjectsliving in urban areas than in those in the rural environment (medians=210.50 and 92.50 ng/L, respectively). These resultswere confirmed by multivariate linear regression model. In conclusion, we found that u-UB is a good biomarker of benzeneexposure in general population. In addition, u-UB could be considered as a synthetic biological index for the assessment ofpopulation exposure to atmospheric pollution.