Assessment of the cancer risk posed by complex PAH mixtures in air or soil is commonly preformed using Benzo(a)pyrene (BP) as an indicator or by applying toxic equivalency factors (TEFs). These concepts might grossly underestimate the risk as ours and others data show strong synergistic effects between PAHs. The objective of the present research is to study inflammatory and carcinogenic effects of ambient air PM and to assess the health risk that can be ascribed to combination effects of the complex mixture of PAHs and particles in the air PM. The research is important for sustainable development as human exposure to PM air pollution have been linked with adverse health effects such as lung cancer, cardiovascular and respiratory diseases, premature mortality among adults and even increased infant mortality. The project is a true multidisciplinary collaboration that involves toxicology, analytical chemistry and atmospheric science. It combines cell exposure systems, chemical fractionation of carcinogenic PAHs with molecular toxicological methods and population exposure modeling. It will produce unique data that can be used for improved risk assessment and abatement strategies.