# The Air Quality Standards (Wales) Regulations 2007, Part 3: Group B pollutants


Population of zone (thousands)
If maximum concentrations exceed the upper assessment threshold
If maximum concentrations are between the upper and lower assessment thresholds
Arsenic, Cadmium, Nickel
Benzo(a) pyrene
Arsenic, Cadmium, Nickel
Benzo(a)pyrene
(1) To include at least one urban-background station and for benzo(a)pyrene also one traffic-oriented station provided this does not increase the number of sampling points.
0—749
1
1
1
1
750—1,999
2
2
1
1
2,000—3,749
2
3
1
1
3,750—4,749
3
4
2
2
4,750—5,999
4
5
2
2
=<6,000
5
5
2
2

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Source: https://www.legislation.gov.uk/wsi/2007/717/schedule/6/part/3 (the official version)
Page: https://openlegislation.uk/air-quality-standards-wales-regulations-2007/schedule-6/part-3
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.