# The Air Quality Standards (Wales) Regulations 2007, Part 2: Assessment thresholds for Group B pollutants


Upper assessment threshold
60% of target value (3.6 ng/m3)
Lower assessment threshold
40% of target value (2.4 ng/m3)

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Source: https://www.legislation.gov.uk/wsi/2007/717/schedule/4/part/2 (the official version)
Page: https://openlegislation.uk/air-quality-standards-wales-regulations-2007/schedule-4/part-2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.