Air quality plans - Article 23
Target values of air quality plan
Article 23 deals with the situation that, in a given zone or agglomeration of a Member State, limit values, including a relevant margin of tolerance, are exceeded. The provision also applies when target values that were fixed in Directive 2008/50/EC, are exceeded.
Target values are values that were fixed in order to prevent, avoid or reduce harmful effects on humans or the environment. After the transition period of target values for PM2.5 , specified in Article 15 and Article 16(1) of Directive 2008/50/EC, expired on 1 January 2015, target values now only exist for ground-level ozone. Annex VII Section A.1 provides for this:
| Objective | Averaging period | Target value |
| Protection of Human Health | maximum daily eight-hour mean | 120 microgram/m³* |
| Protection of vegetation | May to July | 18.000 microgram/m³** |
* the first target value may be exceeded on up to 25 days per calendar year, averaged over three years.
** averaged over 5 years