Review of evidence on health aspects of air pollution

This report presents answers to 22 questions relevant for the review of European policies on air pollution and addressing health aspects of these policies. The answers were developed by a large group of researchers engaged in the WHO project ‘Review of evidence on health aspects of air pollution – REVIHAAP’. The experts reviewed and discussed the newly accumulated scientific evidence on health effects of air pollution, formulating science-based conclusions and drafting the answers.

The review concludes that a considerable amount of new scientific information on health effects of particulate matter, ozone and nitrogen dioxide, observed at levels commonly present in Europe, has been published in the recent years. This new evidence supports the scientific conclusions of the WHO Air Quality Guidelines, last updated in 2005, and indicates that the effects can occur at air pollution concentrations lower than those serving to establish the 2005 Guidelines. It also provides scientific arguments for the decisive actions to improve air quality and reduce the burden of disease associated with air pollution in Europe.

The authors suggest that the current guidelines for some particulate matter (PM2.5) should be re-examined in the light of recent results from long-term studies that have shown increased rates of mortality at concentrations well below the current guidelines of 10 micrograms per m3. The evidence suggests that there is no ‘safe’ threshold.

Extensive rationale for the answers, including the list of key references, will be provided in the final report from the project.