Chapter 17 Urban air pollution

Current scientific evidence, derived largely from studies in North America and Western Europe (NAWE), indicates that urban air pollution, which is derived largely from combustion sources, causes a spectrum of health effects ranging from eye irritation to death. Recent assessments suggest that the impacts on public health may be considerable. This evidence has increasingly been used by national and international agencies to inform environmental policies, and quantification of the impact of air pollution on public health has gradually become a critical component in policy discussions as governments weigh options for the control of pollution. Quantifying the magnitude of these health impacts in cities worldwide, however, presents considerable challenges owing to the limited availability of information on both effects on health and on exposures to air pollution in many parts of the world. Man-made urban air pollution is a complex mixture with many toxic components. We have chosen to index this mixture in terms of particulate matter (PM), a component that has been linked consistently with serious health effects, and, importantly, levels of which can be estimated worldwide. Exposure to PM has been associated with a wide range of effects on health, but effects on mortality are arguably the most important, and are also most amenable to global assessment. Our estimates, therefore, consider only mortality. Currently, most epidemiological evidence and data on air quality that could be used for such estimates comes from developed countries. We have had, therefore, to make assumptions concerning factors such as the transferability of risk functions, exposure of the population and their underlying vulnerability to air pollution, while trying to ensure that these assumptions are transparent and that the uncertainty associated with them is assessed through appropriate sensitivity analyses. Chapter 17