{
  "url": "https://openlegislation.uk/air-quality-limit-values-wales-regulations-2002/schedule-2/part-I/paragraph-wrapper3n1",
  "json_url": "https://openlegislation.uk/air-quality-limit-values-wales-regulations-2002/schedule-2/part-I/paragraph-wrapper3n1.json",
  "legislation": "wsi/2002/3183",
  "legislation_title": "The Air Quality Limit Values (Wales) Regulations 2002",
  "legislation_url": "https://openlegislation.uk/air-quality-limit-values-wales-regulations-2002",
  "path": "schedule/2/part/I/paragraph/wrapper3n1",
  "kind": "paragraph",
  "number": null,
  "heading": null,
  "text": "The following upper and lower assessment thresholds will apply:\nSULPHUR DIOXIDE\n(a)\nHealth protection\nEcosystem protection\nUpper assessment threshold\n60% of 24-hour limit value (75μg/m3, not to be exceeded more than 3 times in any calendar year)\n60% of winter limit value (12μg/m3)\nLower assessment threshold\n40% of 24-hour limit value (50μg/m3), not to be exceeded more than 3 times in any calendar year)\n40% of winter limit value (8μg/m3)\nNITROGEN DIOXIDE AND OXIDES OF NITROGEN\n(b)\nHourly limit value for the protection of human health (NO2)\nAnnual limit value for the protection of human health (NO2)\nAnnual limit value for the protection of vegetation (NOx)\nUpper assessment value\n70% of limit value (140μg/m3, not to be exceeded more than 18 times in any calendar year)\n80% of limit value (32μg/m3)\n80% of limit value (24μg/m3)\nLower assessment value\n50% of limit value (100μg/m3, not to be exceeded more than 18 times in any calendar year).\n65% of limit value (26μg/m3)\n65% of limit value (19.5μg/m3)\nPARTICULATE MATTER\n(c)\n24-hour average\nAnnual average\nUpper assessment threshold\n60% of limit value (30μg/m3, not to be exceeded more than seven times in any calendar year).\n70% of limit value (14μg/m3)\nLower assessment threshold\n40% of limit value (20μg/m3, not to be exceeded more than seven times in any calendar year).\n50% of limit value (10μg/m3)\nLEAD\n(d)\nAnnual average\nUpper assessment threshold\n70% of limit value (0.35μg/m3)\nLower assessment threshold\n50% of limit value (0.25μg/m3)\nBENZENE\n(e)\nAnnual average\nUpper assessment threshold\n70% of limit value (3.5μg/m3)\nLower assessment threshold\n40% of limit value (2μg/m3)\nCARBON monoxide\n(f)\nEight-hour average\nUpper assessment threshold\n70% of limit value (7 mg/m3)\nLower assessment threshold\n50% of limit value (5 mg/m3)",
  "extent": "E+W",
  "status": null,
  "version": "current",
  "annotations": [
    {
      "type": "M",
      "label": "M1",
      "text": "The upper and lower assessment thresholds for PM10 are based on the indicative limit values for 1 January 2010, which will be reviewed in the light of further information on health and environmental effects, technical feasibility and experience in the application of the existing “Stage 1\" limit values.See Article 10 of Directive 99/30/EC."
    }
  ],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/wsi/2002/3183/schedule/2/part/I/paragraph/wrapper3n1",
    "retrieved_at": "2026-10-29T00:12:37.924889+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."
}