{
  "url": "https://openlegislation.uk/eu-directive-2008-50/annex-VII/division-A/division-2",
  "json_url": "https://openlegislation.uk/eu-directive-2008-50/annex-VII/division-A/division-2.json",
  "legislation": "eudr/2008/50",
  "legislation_title": "Directive 2008/50/EC of the European Parliament and of the Council of 21 May 2008 on ambient air quality and cleaner air for Europe",
  "legislation_url": "https://openlegislation.uk/eu-directive-2008-50",
  "path": "annex/VII/division/A/division/2",
  "kind": "division",
  "number": "2",
  "heading": "Criteria",
  "text": "The following criteria shall be used for checking validity when aggregating data and calculating statistical parameters:\nIn cases where all possible measured data are not available, the following factor shall be used to calculate AOT40 values:\nAOT40estimate = AOT40measured ×\ntotal possible number of hours (*)\nnumber of measured hourly values\n(*)\nbeing the number of hours within the time period of AOT40 definition, (i.e. 08:00 to 20:00 CET from 1 May to 31 July each year, for vegetation protection and from 1 April to 30 September each year for forest protection).\nParameter\nRequired proportion of valid data\nOne hour values\n75 % (i.e. 45 minutes)\nEight hours values\n75 % of values (i.e. six hours)\nMaximum daily 8 hours mean from hourly running 8 hours\n75 % of the hourly running eight hours averages (i.e. 18 eight-hourly averages per day)\nAOT40\n90 % of the one hour values over the time period defined for calculating the AOT40 value\nAnnual mean\n75 % of the one hour values over summer (April to September) and 75 % over winter (January to March, October to December) seasons separately\nNumber of exceedances and maximum values per month\n90 % of the daily maximum eight hours mean values (27 available daily values per month)\n90 % of the one hour values between 8.00 and 20.00 CET\nNumber of exceedances and maximum values per year\nfive out of six months over the summer season (April to September)",
  "extent": "E+W+S+N.I.",
  "status": null,
  "version": "current",
  "annotations": [
    {
      "type": "footnote",
      "label": "f1",
      "text": "In cases where all possible measured data are not available, the following factor shall be used to calculate AOT40 values: AOT40estimate = AOT40measured ×total possible number of hours (*)number of measured hourly values (*) being the number of hours within the time period of AOT40 definition, (i.e. 08:00 to 20:00 CET from 1 May to 31 July each year, for vegetation protection and from 1 April to 30 September each year for forest protection)."
    }
  ],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/eudr/2008/50/annex/VII/division/A/division/2",
    "retrieved_at": "2026-11-01T15:22:21.245568+00:00"
  },
  "licence": "Open Government Licence v3.0",
  "licence_url": "https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/",
  "attribution": "Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives."
}