Search Legislation

The Air Quality Standards (Wales) Regulations 2007

Status:

This is the original version (as it was originally made). This item of legislation is currently only available in its original format.

Regulation 13(5)

SCHEDULE 4Assessment thresholds

PART 1Assessment thresholds for Group A pollutants

Benzene

Annual average
Upper assessment threshold70% of limit value (3.5 μg/m3)
Lower assessment threshold40% of limit value (2 μg/m3)

Carbon monoxide

Eight-hour average
Upper assessment threshold70% of limit value (7 mg/m3)
Lower assessment threshold50% of limit value (5 mg/m3)

Lead

Annual average
Upper assessment threshold70% of limit value (0.35 μg/m3)
Lower assessment threshold50% of limit value (0.25 μg/m3)

Nitrogen dioxide (NO2) and oxides of nitrogen (NOx)

Hourly limit value for the protection of human health (NO2)Annual limit value for the protection of human health (NO2)Annual limit value for the protection of vegetation (NOx)
Upper assessment threshold70% of limit value (140 μg/m3), not to be exceeded more than 18 times in any calendar year80% of limit value (32 μg/m3)80% of limit value (24 μg/m3)
Lower assessment threshold50% of limit value (100 μg/m3), not to be exceeded more than 18 times in any calendar year65% of limit value (26 μg/m3)65% of limit value (19.5 μg/m3)

PM10

24-hour averageAnnual average
Upper assessment threshold60% of limit value (30 μg/m3), not to be exceeded more than 7 times in any calendar year70% of limit value (14 μg/m3)
Lower assessment threshold40% of limit value (20 μg/m3), not to be exceeded more than 7 times in any calendar year50% of limit value (10 μg/m3)

Sulphur dioxide

Health protectionEcosystem protection
Upper assessment threshold60% of 24-hour limit value (75 μg/m3), not to be exceeded more than 3 times in any calendar year60% of winter limit value (12 μg/m3)
Lower assessment threshold40% of 24-hour limit value (50 μg/m3), not to be exceeded more than 3 times in any calendar year40% of winter limit value (8 μg/m3)

PART 2Assessment thresholds for Group B pollutants

Arsenic

Upper assessment threshold60% of target value (3.6 ng/m3)
Lower assessment threshold40% of target value (2.4 ng/m3)

Benzo(a)pyrene

Upper assessment threshold60% of target value (0.6 ng/m3)
Lower assessment threshold40% of target value (0.4 ng/m3)

Cadmium

Upper assessment threshold60% of target value (3 ng/m3)
Lower assessment threshold40% of target value (2 ng/m3)

Nickel

Upper assessment threshold70% of target value (14 ng/m3)
Lower assessment threshold50% of target value (10 ng/m3)

PART 3Determination of when assessment thresholds are exceeded

1.  Exceedances of upper and lower assessment thresholds must be determined on the basis of concentrations during the previous five years where sufficient data are available. An assessment threshold will be deemed to have been exceeded if it has been exceeded during at least three separate years out of the previous five years.

2.  Where fewer than five years' data are available, measurement campaigns of short duration during the period of the year and at locations likely to be typical of the highest concentrations may be combined with results obtained from emission inventories and modelling to determine exceedances of the upper and lower assessment thresholds.

Back to top

Options/Help

Print Options

Close

Legislation is available in different versions:

Latest Available (revised):The latest available updated version of the legislation incorporating changes made by subsequent legislation and applied by our editorial team. Changes we have not yet applied to the text, can be found in the ‘Changes to Legislation’ area. The revised version is currently only available in English.

Original (As Enacted or Made) - English: The original English language version of the legislation as it stood when it was enacted or made. No changes have been applied to the text.

Original (As Enacted or Made) - Welsh:The original Welsh language version of the legislation as it stood when it was enacted or made. No changes have been applied to the text.

Close

Opening Options

Different options to open legislation in order to view more content on screen at once

Close

More Resources

Access essential accompanying documents and information for this legislation item from this tab. Dependent on the legislation item being viewed this may include:

  • the original print PDF of the as enacted version that was used for the print copy
  • lists of changes made by and/or affecting this legislation item
  • confers power and blanket amendment details
  • all formats of all associated documents
  • correction slips
  • links to related legislation and further information resources
Close

More Resources

Use this menu to access essential accompanying documents and information for this legislation item. Dependent on the legislation item being viewed this may include:

  • the original print PDF of the as made version that was used for the print copy
  • correction slips

Click 'View More' or select 'More Resources' tab for additional information including:

  • lists of changes made by and/or affecting this legislation item
  • confers power and blanket amendment details
  • all formats of all associated documents
  • links to related legislation and further information resources