The exposure-response function (quantitative variation of a health outcome per unit of pollutant load) was derived by a meta-analytical assessment of various (international) studies selected from the peer-reviewed epidemiological literature. The effect estimate (gradient) was calculated as the variance weighted average across the results of all studies included in the meta-analysis. In this project, the impact of air pollution on mortality is based on the long-term effect. This approach is chosen because the impact of air pollution is a combination of acute short-term as well as cumulative long-term effects. For example, lifetime air pollution exposure may lead to recurrent injury and, in the long term, cause.
