# The Air Quality Limit Values (Wales) Regulations 2002, Paragraph

Extent: E+W

The following data-quality objectives for the required accuracy of assessment methods, of minimum time coverage and of data capture of measurement are laid down to guide quality-assurance programmes.
Sulphur dioxide, nitrogen dioxide and oxides of nitrogen
Particulate matter and lead
Continuous measurement
Accuracy
15%
25%
Minimum data capture
90%
90%
Indicative measurement
Accuracy
25%
50%
Minimum data capture
90%
90%
Minimum time coverage
14% (One measurement a week at random, evenly distributed over the year, or eight weeks evenly distributed over the year.)
14% (One measurement a week at random, evenly distributed over the year, or eight weeks evenly distributed over the year.)
Modelling
Accuracy:
Hourly averages
50%—60%
Daily averages
50%
Annual averages
30%
50%
Objective estimation
Accuracy:
75%
100%

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Source: https://www.legislation.gov.uk/wsi/2002/3183/schedule/5/part/I/paragraph/wrapper14n1 (the official version)
Page: https://openlegislation.uk/air-quality-limit-values-wales-regulations-2002/schedule-5/part-I/paragraph-wrapper14n1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.