# The Air Quality Limit Values (Wales) Regulations 2001, Part III: PARTICULATE MATTER (PM10)


Averaging Period
Limit value
Margin of tolerance
Date by which limit value is to be met
1 24-hour limit value for the protection of human health
24 hours
50μg/m3 PM10 not to be exceeded more than 35 times a calendar year
50% on 19 July 1999, reducing on 1 January 2001 and every 12 months thereafter by equal annual percentages to reach 0% by 1 January 205
1 January 2005
2 Annual limit value for the protection of human health
Calendar year
40 μg/m3PM10
20% on 19 July 1999 reducing on 1 January 2001 and every 12 months thereafter by equal annual percentages to reach 0% by 1 January 2005
1 January 2005

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Source: https://www.legislation.gov.uk/wsi/2001/2683/schedule/1/part/III (the official version)
Page: https://openlegislation.uk/air-quality-limit-values-wales-regulations-2001/schedule-1/part-III
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.