{
  "url": "https://openlegislation.uk/air-quality-limit-values-regulations-2001/schedule-3/part-II",
  "json_url": "https://openlegislation.uk/air-quality-limit-values-regulations-2001/schedule-3/part-II.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/3/part/II",
  "kind": "part",
  "number": "II",
  "heading": "Microscale siting",
  "text": "The following guidelines should be met as far as practicable:\nthe flow around the inlet sampling probe should be unrestricted without any obstructions affecting the airflow in the vicinity of the sampler (normally some metres away from buildings, balconies, trees and other obstacles and at least 0.5 m from the nearest building in the case of sampling points representing air quality at the building line);\nin general, the inlet sampling point should be between 1.5 m (the breathing zone) and 4 m above the ground. Higher positions (up to 8 m) may be necessary in some circumstances. Higher siting may also be appropriate if the station is representative of a large area;\nthe inlet probe should not be positioned in the immediate vicinity of sources in order to avoid the direct intake of emissions unmixed with ambient air;\nthe sampler’s exhaust outlet should be positioned so that recirculation of exhaust air to the sampler inlet is avoided;\nlocation of traffic-orientated samplers;\nfor all pollutants, such sampling points should be at least 25 m from the edge of major junctions and at least 4 m from the centre of the nearest traffic lane,\nfor nitrogen dioxide, inlets should be no more than 5 m from the kerbside,\nfor particulate matter and lead, inlets should be sited so as to be representative of air quality near to the building line.\nThe following factors may also be taken into account:\ninterfering sources;\nsecurity;\naccess;\navailability of electrical power and telephone communications;\nvisibility of the site in relation to its surroundings;\nsafety of public and operators;\nthe desirability of co-locating sampling points for different pollutants;\nplanning requirements.",
  "extent": null,
  "status": null,
  "version": "current",
  "annotations": [],
  "outstanding_effects": [
    {
      "type": "substituted",
      "affecting": "uksi/2002/3117",
      "affecting_title": "The Air Quality Limit Values (Amendment) Regulations 2002"
    },
    {
      "type": "words inserted",
      "affecting": "uksi/2002/3117",
      "affecting_title": "The Air Quality Limit Values (Amendment) Regulations 2002"
    },
    {
      "type": "words substituted",
      "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/3/part/II",
    "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."
}