Human exposure to complex mixtures of polycyclic organic matter (POM) from the products of incomplete combustion contribute to the potential lung cancer risk in urban areas. The most ubiquitous emission sources outdoors in populated areas are residential motor vehicles and residential heating, while environmental tobacco smoke is usually the major combustion source in indoor air. In addition to these urban combustion sources, there are industrial and municipal sources that may also have a significant impact on human exposure to carcinogenic agents due to their high DNA adduct and tumor initiating potency. This review focuses on new approaches to assess human exposure to POM using source apportionment, personal exposure monitoring, and biomarker methods.