Review: The Applicability of Epidemiological Methods to the Assessment of the Risks to Human Health of Indoor Air Pollution: An Overview

Western populations spend the vast majority of their time indoors, and can be exposed to a range of indoor pollutants that may have adverse effects on health. Scientists and regulators need to be able to understand and quantify the nature of the potential risks posed by the indoor environment. Epidemiological methods are available to investigate relationships between indoor pollutant exposure and health impacts, but involve many assumptions and have inherent uncertainties. To establish an accurate understanding of the knowledge base and a sound interpretation of the significance of the results obtained, it is essential that epidemiological study findings are not accepted uncritically and that the advantages/weaknesses of each design are fully understood. This overview identifies the strengths and weaknesses of the various epidemiological techniques used to study indoor air pollution, and considers the place of epidemiological data within the wider weight of evidence considerations necessary to establish causality of associations and accurately determine potential risk. It is evident that epidemiology remains a key science in the study of associations between indoor air pollutants and diseases like asthma, and a number of recommendations are made that may improve the application of this methodology and the interpretation of derived results.