{
  "url": "https://openlegislation.uk/air-quality-wales-regulations-2000/schedule/part-II/paragraph-1n2",
  "json_url": "https://openlegislation.uk/air-quality-wales-regulations-2000/schedule/part-II/paragraph-1n2.json",
  "legislation": "wsi/2000/1940",
  "legislation_title": "The Air Quality (Wales) Regulations 2000",
  "legislation_url": "https://openlegislation.uk/air-quality-wales-regulations-2000",
  "path": "schedule/part/II/paragraph/1n2",
  "kind": "paragraph",
  "number": "1",
  "heading": null,
  "text": "(1) A running annual mean is a mean which is calculated on an hourly basis, yielding one running annual mean per hour. The running annual mean for a substance at a particular location for a particular hour is the mean of the hourly levels for that substance at that location for that hour and the preceding 8759 hours.\n(2) For the purpose of the calculation of a running annual mean, the hourly level for a substance at a particular location is either:\n(a) the level at which that substance is recorded as being present in the air at that location during the hour on the basis of a continuous sample of air taken during that hour for at least 30 minutes; or\n(b) the mean of the levels recorded at that location on the basis of 2 or more samples of air taken during the hour for an aggregate period of at least 30 minutes.",
  "extent": "E+W",
  "status": null,
  "version": "current",
  "annotations": [
    {
      "type": "I",
      "label": "I1",
      "text": "Sch. Pt. 2 para. 1 in force at 1.8.2000, see reg. 1(1)"
    }
  ],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/wsi/2000/1940/schedule/part/II/paragraph/1n2",
    "retrieved_at": "2026-10-29T00:18:33.450536+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."
}