Quantification of health effects of exposure to air pollution

Air pollution is a significant factor shaping public health Over the past decade epidemiological studies in Europe and worldwide have measured increases in mortality and morbidity associated with air pollution.1,2 As evidence of health effects of air pollution has accumulated, European governments, the World Health Organisation (WHO), and other groups have begun to use data from these studies to inform environmental policies through, for example, quantitative estimates of impact of air pollution on public health.3–6 Health impact assessment involves extrapolation of exposure-health associations measured in epidemiological studies to a target population characterised by a certain observed or predicted exposure pattern.7 The analysis must address important methodological issues relevant to both its design and conduct. Clarity in defining these issues is a prerequisite for proper interpretation of the results in the policy arena. Nevertheless, the results are often prone to misinterpretation, even when the assessment is done carefully, and its multiple uncertainties are carefully presented and explained to decision makers, the press, and the public. WHO recently convened a Working Group to examine key methodological issues in health impact assessment of air pollution using epidemiological data, and to recommend approaches to the conduct of such assessments. The Working Group comprised experts who develop and apply methods for health risk analysis, and scientists involved in the communication of the results of the analysis to the public or decision makers. The Working Group formulated recommendations on the framework and methods of health impact assessment. Their discussions focused on the conditions pertinent to the developed countries, where most of the studies documenting the relations between air pollution and health were performed. The WHO report presenting the Working Group discussions and its recommendations has been published recently.8 This paper summarises the WHO report and communicates its main messages to …