Air quality management

The EU Ambient Air Quality Directives (AAQDs) oblige EU Member States to divide their territories in zones and agglomerations for the purposes of air quality assessment and management. 

Air quality assessment and air quality management should be carried out in all zones and agglomerations, and each zone and agglomeration should be classified in relation to the assessment thresholds for the ambient concentrations of sulphur dioxide (SO₂), nitrogen dioxide (NO₂) or nitrogen oxides (NO_x), particulate matter (PM₁₀, PM_2.5), lead, benzene or carbon monoxide as specified in the AAQDs.

The AAQDs also require Member States to take appropriate measures to ensure compliance with the limit and target values within a specified deadline and/or to maintain compliance once the limit and target values have been met. Therefore, air quality plans are required in polluted zones and agglomerations where air quality standards are exceeded and/or in zones and agglomerations where there is a risk of exceedances.

These plans aim to reduce concentrations of air pollutants to below the legislative limit and target values specified in the Directives in the shortest possible time. Details of the plans must be reported by Member States to the European Commission via the European Environment Agency (EEA). This is the information reported by Member States according to the rules of Commission Implementing Decision 2011/850/EU.

When and where concentrations of pollutants in ambient air exceed the relevant target values or limit values, the AAQ Directives require Member States to develop air quality plans and/or take appropriate measures (depending on the pollutant), so that the related target values or limit values are achieved in the respective zones and agglomerations, and that exceedance periods are kept as short as possible.

In many Member States, responsibility for developing and implementing air quality plans has been devolved by national authorities to local governments.

Air quality plans typically include a series of measures based on an assessment of air quality and trend forecasts for the future, and detailed analysis of the high level of concentrations, including the sources responsible. Understanding the reasons for high levels of air pollution is crucial for decision-making on urban air quality management.