# Commission Implementing Decision of 12 December 2011 laying down rules for Directives 2004/107/EC and 2008/50/EC of the European Parliament and of the Council as regards the reciprocal exchange of information and reporting on ambient air quality (notified under document C(2011) 9068) (2011/850/EU), Division: Calculation of the Average Exposure Indicator (AEI) in accordance with Part A of Annex XIV to Directive 2008/50/EC

Extent: E+W+S+N.I.

Calculation is made for each individual year, calculating PM2,5 annual means for each of the selected sampling points. The selection of the sampling points has to be evident from the appropriate information made available.
Valid annual means complying with the data quality objectives are averaged over all designated AEI sites of the appropriate authorities and the appropriate authorities in Wales, Scotland and Northern Ireland and the competent authority in England must cooperate with the Secretary of State to ensure the Secretary of State is able to obtain an annual average.
The procedure is repeated for each of the 3 years, and the three annual averages are then averaged to obtain the AEI.
The AEI shall be made available annually as a three-year running mean. In case of a need to update any of the data that could directly or indirectly (through selection of sampling point) influence the AEI, the complete update of all affected information is necessary.

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Source: https://www.legislation.gov.uk/eudn/2011/850/annex/I/division/A/division/5/division/2 (the official version)
Page: https://openlegislation.uk/eu-decision-2011-850/annex-I/division-A/division-5/division-2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.