Air Pollution Nitrogen Dioxide

7. General Conclusions

• 7.1 Recommendations
• 7.2 What other aspects of air pollution are important to address in the development of air pollution policy in Europe?
• 7.3 Concluding remarks

7.1 Recommendations

Clean air policies aim to develop strategies to reduce the risk of adverse consequences of ambient air pollution for human health and for the environment as a whole. In the case of air pollutants, the concept of thresholds may no longer be useful in setting standards to protect public health. This is because certain population groups are very susceptible and are affected even at low levels, and because we are now able to detect even rare cases. Therefore, the application of the policy principle of providing an adequate margin of safety in order to eliminate adverse effects even for the most susceptible groups may not be realistic.

Risk reduction strategies are nevertheless effective in promoting public health. To develop such strategies, both qualitative and quantitative knowledge about the most relevant effects is required.

Therefore, for ozone and particulate matter, a meta-analysis of available data was recommended. This analysis should evaluate the relative risk increase (risk coefficients) related to ozone and to specific fractions of particulate matter for different health effects (endpoints).

It was also recommended:

• to update the concentration-response table for ozone in the current WHO Air quality guidelines,
• to identify which risk coefficients should be used in order to estimate long term mortality in relation to PM exposure, and
• to carry out a more comprehensive monitoring programme for PM-related health effects (not only relying on PM_2.5) in different European cities.

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7.2 What other aspects of air pollution are important to address in the development of air pollution policy in Europe?

Other substances and pollutants posing risk to health which are currently not adequately addressed in the development of air pollution policy in Europe include:

• Carbon monoxide (CO) and sulphur dioxide (SO₂), with new evidence of links to severe health effects.
• Persistent organic pollutants (POP) such as PAH.
• Heavy metals, in particular lead and some transition metals. Lead is of concern since there are new studies suggesting effects at low concentrations.
• The carcinogenic volatile organic compounds 1.3-butadiene and benzene.
• Nitrogen trichloride, since there is evidence of health effects from this substance from epidemiological studies.

Few experts suggested assessing the health effects from diesel versus gasoline exhaust fumes.

An important issue that remains unresolved concerns the combined effects on health of urban air pollution mix. More...

7.3 Concluding remarks

• The body of evidence has grown stronger over the past few years regarding the health effects of air pollution at levels currently common in Europe.
• There is sufficient evidence to strongly recommend further policy action to reduce levels of particulate matter (PM), nitrogen dioxide (NO₂), and ozone (O₃) in air. This would lead to considerable health benefits.
• Further targeted research and subsequent systematic evaluation is needed to reduce the existing uncertainty.

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