The ambient air of urban centres is polluted with potentially toxic chemicals mostly arising from the combustion or fuels used for transport, heating and industrial activities. Alongside the risk to the general public, atmospheric pollution could be considered an occupational health hazard to professional groups, such us traffic police or professional drivers working in urban areas. Molecular epidemiology can facilitate health risk assessment by investigating the relationship between exposure to environmental pollutants and quantification of biomarkers that lie on the pathway of carcinogenesis upstream of clinical disease. In particularly, biomarkers of early effects and susceptibility are playing an increase role in the investigation of the impact of air pollution on human carcinogenesis.