Modelling the dispersion of particulate matter in air

Europe is poised to establish regulations to limit the concentration of particulate matter (PM) in ambient air under the auspices of the Air Quality and Assessment Directive. PM10, PM2.5 and PM0.1 are defined as particulate matter with a diameter smaller than 10 µm, 2.5 µm and 0.1 µm respectively. These regulations are intended to set mandatory air quality standards with which Member States will be expected to comply, yet a number of recent studies suggest that elevated particulate concentrations in urban areas during pollution episodes are related to non-local or even transboundary pollution. These studies raise serious concerns about how best to control ambient concentrations of PM, and about the effectiveness of national air quality regulations to control exposure to particulate matter in urban areas. At the same time, certain Member States have expressed a wish to carry out modelling exercises to explore the cost-effectiveness of vehicle emission abatement measures as part of the Auto/Oil-2 Programme.