# The Air Quality Standards Regulations 2010, Paragraph 2


Sampling points must in general be sited to avoid measuring very small micro-environments in their immediate vicinity. Where feasible, the Secretary of State must locate sampling points so as to be representative of air quality in a street segment of no less than 100m in length at traffic-orientated sites or an area of at least 250mx 250m at industrial sites.

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Source: https://www.legislation.gov.uk/uksi/2010/1001/schedule/1/part/2/paragraph/2 (the official version)
Page: https://openlegislation.uk/air-quality-standards-regulations-2010/schedule-1/part-2/paragraph-2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.