http://ec.europa.eu/environment/air/quality/standards.htm
Humans can be adversely affected by exposure to air pollutants in ambient air. In response, the European Union has developed an extensive body of legislation which establishes health based standards and objectives for a number of pollutants in air. These standards and objectives are summarised in the table below. These apply over differing periods of time because the observed health impacts associated with the various pollutants occur over different exposure times.
| Pollutant | Concentration | Averaging period | Legal nature | Permitted exceedences each year |
| Fine articles (PM2.5) | 25 µg/m3*** | 1 year | Target value entered into force 1.1.2010 Limit value enters into force 1.1.2015 |
n/a |
| Sulphur dioxide (SO2) | 350 µg/m3 | 1 hour | Limit value entered into force 1.1.2005 | 24 |
| 125 µg/m3 | 24 hours | Limit value entered into force 1.1.2005 | 3 | |
| Nitrogen dioxide (NO2) | 200 µg/m3 | 1 hour | Limit value entered into force 1.1.2010 | 18 |
| 40 µg/m3 | 1 year | Limit value entered into force 1.1.2010* | n/a | |
| PM10 | 50 µg/m3 | 24 hours | Limit value entered into force 1.1.2005** | 35 |
| 40 µg/m3 | 1 year | Limit value entered into force 1.1.2005** | n/a | |
| Lead (Pb) | 0.5 µg/m3 | 1 year | Limit value entered into force 1.1.2005 (or 1.1.2010 in the immediate vicinity of specific, notified industrial sources; and a 1.0 µg/m3 limit value applied from 1.1.2005 to 31.12.2009) | n/a |
| Carbon monoxide (CO) | 10 mg/m3 | Maximum daily 8 hour mean | Limit value entered into force 1.1.2005 | n/a |
| Benzene | 5 µg/m3 | 1 year | Limit value entered into force 1.1.2010** | n/a |
| Ozone | 120 µg/m3 | Maximum daily 8 hour mean | Target value entered into force 1.1.2010 | 25 days averaged over 3 years |
| Arsenic (As) | 6 ng/m3 | 1 year | Target value enters into force 31.12.2012 | n/a |
| Cadmium (Cd) | 5 ng/m3 | 1 year | Target value enters into force 31.12.2012 | n/a |
| Nickel (Ni) | 20 ng/m3 | 1 year | Target value enters into force 31.12.2012 | n/a |
| Polycyclic Aromatic Hydrocarbons | 1 ng/m3 (expressed as concentration of Benzo(a)pyrene) |
1 year | Target value enters into force 31.12.2012 | n/a |
*Under the new Directive the member State can apply for an extension of up to five years (i.e. maximum up to 2015) in a specific zone. Request is subject to assessment by the Commission. . In such cases within the time extension period the limit value applies at the level of the limit value + maximum margin of tolerance ( 48 µg/m3 for annual NO2 limit value).
**Under the new Directive the Member State was able to apply for an extension until three years after the date of entry into force of the new Directive (i.e. May 2011) in a specific zone. Request was subject to assessment by the Commission. In such cases within the time extension period the limit value applies at the level of the limit value + maximum margin of tolerance (35 days at 75µg/m3 for daily PM10 limit value, 48 µg/m3 for annual Pm10 limit value).
***Standard introduced by the new Directive.
Under EU law a limit value is legally binding from the date it enters into force subject to any exceedances permitted by the legislation. A target value is to be attained as far as possible by the attainment date and so is less strict than a limit value.
The new Directive is introducing additional PM2.5 objectives targetting the exposure of the population to fine particles. These objectives are set at the national level and are based on the average exposure indicator (AEI).
AEI is determined as a 3-year running annual mean PM2.5 concentration averaged over the selected monitoring stations in agglomerations and larger urban areas, set in urban background locations to best assess the PM2.5 exposure to the general population.
| Title | Metric | Averaging period | Legal nature | Permitted exceedences each year |
| PM2.5 Exposure concentration obligation |
20 µg/m3 (AEI) |
Based on 3 year average | Legally binding in 2015 (years 2013,2014,2015) | n/a |
| PM2.5 Exposure reduction target |
Percentage reduction* + all measures to reach 18 µg/m3 (AEI) |
Based on 3 year average | Reduction to be attained where possible in 2020, determined on the basis of the value of exposure indicator in 2010 | n/a |
* Depending on the value of AEI in 2010, a percentage reduction requirement ( 0,10,15, or 20%) is set in the Directive. If AEI in 2010 is assessed to be over 22 µg/m3, all appropriate measures need to be taken to achieve 18 µg/m3 by 2020.
Principles
European legislation on air quality is built on certain principles. The first of these is that the Member States divide their territory into a number of zones and agglomerations. In these zones and agglomerations, the Member States should undertake assessments of air pollution levels using measurements and modelling and other empirical techniques. Where levels are elevated, the Member States should prepare an air quality plan or programme to ensure compliance with the limit value before the date when the limit value formally enters into force. In addition, information on air quality should be disseminated to the public. See more under Implementation.