# Air Quality Regulations (Northern Ireland) 2003, Paragraph 3: Interpretation

Extent: N.I.
Status: prospective

(1) A maximum daily running 8-hour mean is calculated on a daily basis. The maximum daily running 8-hour mean for a particular substance at a particular location for a particular day is the maximum of the running 8-hour means ending during that day.
(2) For the purpose of sub-paragraph (1) a “running 8-hour mean” is a mean, which is calculated on an hourly basis, yielding one running 8 hour mean per hour. The running 8-hour mean for the relevant substance at the relevant location for a particular hour is the mean of the hourly means for the substance at the location for the hour and the preceding 7 hours.

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Source: https://www.legislation.gov.uk/nisr/2003/342/schedule/paragraph/3 (the official version)
Page: https://openlegislation.uk/air-quality-regulations-northern-ireland-2003/schedule/paragraph-3
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.