The ultimate goal of any clean air policy is to develop strategies to reduce the risk of adverse effects on human health and the environment as a whole caused by ambient air pollution. With the existence of very susceptible populations and the ability to detect effects even if they are infrequent, we may be confronted with situations when the concept of thresholds is no longer useful in setting standards to protect public health. The principle of eliminating adverse effects with an adequate margin of safety even for the most susceptible groups may not be realistic. However, risk reduction strategies are and will continue to be powerful tools in promoting public health. The development of such strategies requires not only qualitative, but also quantitative knowledge on the most relevant adverse effects.
Therefore, the working group recommended, as a follow up of this work, a meta-analysis using the bibliographic database developed at the St George’s Hospital Medical School. This meta-analysis should be guided by a small task group and should derive updated cause-specific risk coefficients for the following health endpoints, which can also be used in subsequent health impact assessments:
- Mortality short-term: all causes all ages
- Respiratory hospital admissions: adults, children, elderly
- Symptom exacerbation in asthmatics
PM (PPM2.5; coarse; BS; PM10)
- Mortality short-term
- Hospital admissions/Emergency room visits
The working group also recommended
- an update of the concentration-response table for O3 in the current WHO AQG, which is based on controlled exposure, considering lung function and inflammation under new evidence and
- an identification of those risk coefficients to be used within CAFE to estimate long term mortality in relation to PM exposure.
In addition, the working group noted that the recommendation to use PM2.5 as indicator for PM- related health effects does not imply that PM2.5 is the only relevant parameter to characterize PM pollution. Therefore, it was recommended to set up a more comprehensive monitoring programme in different European cities (possibly including PM10, PM2.5, PM1, BS, PM composition, gases), which, in combination with properly designed health studies, could lead to an additional gain in knowledge on the health effects of ambient air pollution in the coming years.