{
  "url": "https://openlegislation.uk/air-quality-limit-values-regulations-2001/schedule-2/part-I",
  "json_url": "https://openlegislation.uk/air-quality-limit-values-regulations-2001/schedule-2/part-I.json",
  "legislation": "uksi/2001/2315",
  "legislation_title": "The Air Quality Limit Values Regulations 2001",
  "legislation_url": "https://openlegislation.uk/air-quality-limit-values-regulations-2001",
  "path": "schedule/2/part/I",
  "kind": "part",
  "number": "I",
  "heading": "Upper and lower assessment thresholds",
  "text": "The following upper and lower assessment thresholds will apply:\n(a)\nSULPHUR DIOXIDE\nHealth protection\nEcosystem protection\nUpper assessment threshold\n60% of 24-hour limit value (75 μg/m3), not to be exceeded more than 3 times in any calendar year\n60% of winter limit value (12 μg/m3)\nLower assessment threshold\n40% of 24-hour limit value (50 μg/m3), not to be exceeded more than 3 times in any calendar year\n40% of winter limit value (8 μg/m3)\n(b)\nNITROGEN DIOXIDE AND OXIDES OF NITROGEN\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 (140 μg/m3), not to be exceeded more than 18 times in any calendar year\n80% of limit value (32 μg/m3)\n80% of limit value (24 μg/m3)\nLower assessment value\n50% of limit value (100 μg/m3), not to be exceeded more than 18 times in any calendar year\n65% of limit value (26 μg/m3)\n65% of limit value (19.5 μg/m3)\n(c)\nPARTICULATE MATTER\n24-hour average\nAnnual average\nUpper assessment threshold\n60% of limit value (30 μg/m3), not to be exceeded more than seven times in any calendar year\n70% of limit value (14 μg/m3)\nLower assessment threshold\n40% of limit value (20 μg/m3), not to be exceeded more than seven times in any calendar year\n50% of limit value (10 μg/m3)\n(d)\nLEAD\nAnnual average\nUpper assessment threshold\n70% of limit value (0.35 μg/m3)\nLower assessment threshold\n50% of limit value (0.25 μg/m3)",
  "extent": null,
  "status": null,
  "version": "current",
  "annotations": [],
  "outstanding_effects": [
    {
      "type": "words substituted",
      "affecting": "uksi/2002/3117",
      "affecting_title": "The Air Quality Limit Values (Amendment) Regulations 2002"
    },
    {
      "type": "inserted",
      "affecting": "uksi/2002/3117",
      "affecting_title": "The Air Quality Limit Values (Amendment) Regulations 2002"
    }
  ],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/uksi/2001/2315/schedule/2/part/I",
    "retrieved_at": "2026-10-29T07:45:21.655109+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."
}