# The Air Quality Standards Regulations 2010, Schedule 6: Critical levels for the protection of vegetation


Oxides of Nitrogen
Averaging period
Critical level
Calendar year
30 µg/m3 NOx
Sulphur dioxide
Averaging period
Critical level
Calendar year and winter (1st October to 31st March)
20 µg/m3

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Source: https://www.legislation.gov.uk/uksi/2010/1001/schedule/6 (the official version)
Page: https://openlegislation.uk/air-quality-standards-regulations-2010/schedule-6
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.