# The Air Quality Standards (Wales) Regulations 2007, Paragraph 18


The uncertainty for modelling and objective estimation means the maximum deviation of the measured and calculated concentration levels, over the period for calculating the appropriate threshold, without taking into account the timing of events.

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Source: https://www.legislation.gov.uk/wsi/2007/717/schedule/8/paragraph/18 (the official version)
Page: https://openlegislation.uk/air-quality-standards-wales-regulations-2007/schedule-8/paragraph-18
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.