# The Air Quality (England) Regulations 2000, Paragraph 1: Interpretation


“PM10” means particulate matter which passes through a size-selective inlet with a 50% efficiency cut-off at 10μm aerodynamic diameter.

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Source: https://www.legislation.gov.uk/ukdsi/2000/0110987640/schedule/paragraph/1n2 (the official version)
Page: https://openlegislation.uk/draft-air-quality-england-regulations-2000/schedule/paragraph-1n2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.