# The Air Quality Limit Values (Wales) Regulations 2002, Paragraph

Extent: E+W

The uncertainty (on a 95% confidence interval) of the assessment methods shall be evaluated in accordance with the “Guide to the Expression of Uncertainty of Measurements" (ISO 1993) or the methodology of ISO 5725:1994 . The percentages for uncertainty in the above table are given for individual measurements averaged over the period considered by the limit value, for a 95% confidence interval. The uncertainty for the fixed measurements should be interpreted as being applicable in the region of the appropriate limit value.

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Source: https://www.legislation.gov.uk/wsi/2002/3183/schedule/5/part/I/paragraph/wrapper20n1 (the official version)
Page: https://openlegislation.uk/air-quality-limit-values-wales-regulations-2002/schedule-5/part-I/paragraph-wrapper20n1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.