Location and number of sampling points
7.—(1) The Welsh Ministers must install sampling points in accordance with the criteria set out in Annex III to Directive 2008/50/EC for the assessment of sulphur dioxide, nitrogen dioxide and oxides of nitrogen, PM10, PM2·5, lead, benzene and carbon monoxide.
(2) In zones where fixed measurements are the sole source of information for the assessment of air quality in relation to any pollutant mentioned in paragraph (1), the number of sampling points for that pollutant must be greater than or equal to the minimum number specified in Section A of Annex V to Directive 2008/50/EC for the purpose of assessing compliance with alert thresholds and limit values for the protection of human health.
(3) In zones other than agglomerations where fixed measurements are the sole source of information for the assessment of air quality in relation to sulphur dioxide or oxides of nitrogen, the number of sampling points for that pollutant must be greater than or equal to the minimum number specified in Section C of Annex V to Directive 2008/50/EC for the purpose of assessing compliance with critical levels for the protection of vegetation.
(4) In zones where the information from fixed measurements is supplemented by information from modelling or indicative measurements or both–
(a)the number of sampling points specified in Section A of Annex V to Directive 2008/50/EC may be reduced by up to 50% provided that the following conditions are met–
(i)the supplementary methods provide sufficient information for the assessment of air quality in relation to limit values and alert thresholds,
(ii)the supplementary methods provide sufficient information to inform the public as to the state of ambient air quality, and
(iii)the number of sampling points to be installed and the spatial resolution of other techniques are sufficient for the concentration of the relevant pollutant to be established in accordance with the data quality objectives specified in Section A of Annex I to Directive 2008/50/EC and enable assessment results to meet the criteria in Section B of the same Annex; and
(b)the number of sampling points specified in Section C of Annex V to Directive 2008/50/EC may be reduced by up to 50% provided that the assessed concentrations of the relevant pollutant can be established in accordance with the data quality objectives specified in Section A of Annex I to Directive 2008/50/EC.
(5) The Welsh Ministers must install at least one sampling point for the measurement of PM2·5 in rural background locations.