# The Air Quality Standards Regulations (Northern Ireland) 2010, Paragraph 9: Microscale siting of sampling points

Extent: N.I.

Insofar as is practicable, sampling points shall be situated in accordance with the following criteria—
(a) the flow around the inlet sampling probe shall be unrestricted (in general free in an arc of at least 270° or 180° for sampling points at the building line) without any obstructions affecting the airflow in the vicinity of the inlet (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);
(b) in general, the inlet sampling point shall be between 1.5 m (the breathing zone) and 4 m above the ground. Higher siting may also be appropriate if the station is representative of a large area and any derogations should be fully documented;
(c) the inlet probe shall not be positioned in the immediate vicinity of sources in order to avoid the direct intake of emissions unmixed with ambient air;
(d) the sampler’s exhaust outlet must be positioned so that recirculation of exhaust air to the sampler inlet is avoided;
(e) in relation to the location of traffic-orientated samplers, sampling points must be at least 25 m from the edge of major junctions and no more than 10 m from the kerbside. A “major junction” is a junction which interrupts the traffic flow and causes different emissions (due to vehicles stopping and starting) from the rest of the road.

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Source: https://www.legislation.gov.uk/nisr/2010/188/schedule/1/paragraph/9 (the official version)
Page: https://openlegislation.uk/air-quality-standards-regulations-northern-ireland-2010/schedule-1/paragraph-9
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.