Urbanization and the growth of cities have contributed to increase the load of contaminants in the environment. Among contaminants, air pollutants remain a major cause of concern due to their capacity to affect large populations and the fact that several adverse health effects associated with exposure to air pollution have been described in the past few years. This article reviews and discusses some methodological issues involved in the assessment of these health effects. The first issue relates to environmental health indicators (EHI). These indicators can be seen as measures that summarize aspects of the relationship between health and the environment. The EHI methodology proposed by the World Health Organisation for the development of environmental health actions has been applied in the area of air quality. A second aspect relates to the assessment of exposure to air pollution. This is perhaps the most difficult task for studies in this area. Issues concerning different microenvironments (indoor and outdoor) are relevant and should be taken in to account in order to minimize the errors associated with the correct assessment of exposure to air pollutants. Lastly, a brief discussion of the main epidemiological study designs used to examine the association between air pollution and health effects is presented. The advantages and disadvantages of the main study types and their main applications are discussed. These are not the only essential issues when studying the deleterious health effects of air pollution on health. However, in order to have sound environmental health policies one needs well designed and conducted epidemiological studies taking in to account these main issues. In this manner, better information will be available to those involved in the decision-making process regarding air quality in our cities.
Air pollution; Health effects; Environmental health indicators; Exposure assessment; Epidemiological studies
