Recent outcomes in European multicentre projects on ambient particulate air pollution.

The adverse health effects associated with ambient air pollution have triggered epidemiologists, toxicologists and chemists to combine their experience to investigate the toxicity of ambient PM (particulate matter) from European sites with differing traffic intensity, in order to increase the understanding of the role of fine and coarse PM, the role of chemical characteristics and relate that to health effects. Under the European Union 5th Framework Programme (FP5), the HEPMEAP, RAIAP and PAMCHAR projects have utilised high-volume samplers to collect PM in European locations with contrasting PM sources and performed a range of different laboratory investigations. The PM investigated generally induced significant biological responses, with both coarse (2.5-10 microm) and fine (0.1-2.5 microm) PM being able to induce toxic effects. The chemical composition of the PM (also reflecting the differences in the emission-source contribution) has been suggested to play an important role in these responses. Oxidative and immune effects have been demonstrated in several in vitro and animal models. Investigations have also given support for the assumption that asthmatic and elderly subjects with chronic obstructive pulmonary disease may be more susceptible to PM exposure.