Potential sources of bias in the use of individual's recall of the frequency of exposure to air pollution for use in exposure assessment in epidemiological studies: a cross-sectional survey.

Background: In a previous study it has been shown that mean population perception of air pollution correlates well with physical measures of actual air pollution and could be used as a measure of exposure to air pollution, at least for those forms of pollution perceptible to humans. However, for such a measure to be valid researchers would need to be confident that it was not strongly biased by possible confounding variables. This study reports the association between perception of above average levels of air pollution compared with others in the neighbourhood and a number of factors that may influence reporting.

The prevalence of self-reported symptoms of respiratory disease and community belief about the severity of pollution from various sources.

It is postulated that health effects of air pollution may be direct and indirect through people's perception about the severity of pollution and concerns over its impact on their health. A cross sectional postal survey of some 6,559 households was conducted in the area of Ellesmere Port and Neston Borough Council. A total of 3,402 (51.