Since the year 2000, evaluation of the impact of air pollution on people's health has drawn the attention of the general public and has led decision-makers to develop specific health policies. In most of the health impact assessment literature, investigators have reported on long- and short-term effects of air pollution. Here the authors present results of a health impact assessment of short-term effects of particulate matter ≤10 μm in diameter (PM(10)) in the Lombardy region of Italy (2003-2006). The impact was evaluated in terms of numbers of attributable deaths under several counterfactual scenarios of air pollution reduction based on World Health Organization guidelines and European Union limits. The authors found that annual average PM(10) levels exceeding the World Health Organization threshold of 20 μg/m(3) and the European Union limit of 40 μg/m(3) were responsible for 302 and 109 attributable deaths per year, corresponding to attributable community rates of 13 and 5 deaths per 100,000 inhabitants per year, respectively. A 20% reduction in existing PM(10) levels could reduce by more than 30% the burden of short-term deaths linked to ambient air pollution. Therefore, policies for air pollution reduction appear to be necessary in order to protect and improve individual and community health.