# The Air Quality Standards (Wales) Regulations 2007, Paragraph 8: Benzene and carbon monoxide


The uncertainty for modelling and objective estimation is defined as the maximum deviation of the measured and calculated concentration levels, over the period considered by the limit value, without taking into account the timing of the events.

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