The Air Quality Standards (Scotland) Regulations 2010

CHAPTER 1 S Sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter, lead, benzene and carbon monoxide

Assessment thresholds S

5.—(1) The Scottish Ministers must classify each zone according to whether or not the upper or lower assessment thresholds specified in Section A of Annex II to Directive 2008/50/EC are exceeded in relation to sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter, lead, benzene and carbon monoxide.

(2) The Scottish Ministers must review the classification of zones carried out in accordance with paragraph (1) at least every five years, and must do so more frequently than every five years if there are significant changes in the activities which may affect levels of sulphur dioxide, nitrogen dioxide or oxides of nitrogen, particulate matter, lead, benzene or carbon monoxide in ambient air.

(3) When reviewing the classification of zones in accordance with assessment thresholds, the Scottish Ministers must comply with Section B of Annex II to Directive 2008/50/EC.

Assessment criteria S

6.—(1) The Scottish Ministers must assess the level of sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter, lead, benzene and carbon monoxide in ambient air in all zones.

(2) In all zones where the level of any pollutant mentioned in paragraph (1) exceeds the upper assessment threshold for that pollutant referred to in regulation 5, fixed measurements must be used in relation to that pollutant, but may be supplemented by modelling or indicative measurements or both in order to provide adequate information on the spatial distribution of the ambient air quality.

(3) In all zones where the level of any pollutant mentioned in paragraph (1) is below the lower assessment threshold for that pollutant referred to in regulation 5, modelling or estimation techniques or both may be used instead of fixed measurements in relation to that pollutant.

(4) In zones where the level of any pollutant mentioned in paragraph (1) is at or between the upper and lower assessment thresholds for that pollutant, a combination of fixed measurements together with modelling or indicative measurements or both may be used in relation to that pollutant.

(5) In addition to the measurements referred to in paragraphs (1) to (4), the Scottish Ministers must measure PM_2.5 at rural background locations away from significant sources of air pollution, in order to provide information on an annual average basis on the total mass concentration and chemical speciation concentrations of that pollutant.

(6) For the purposes of paragraphs (1) to (5), measurements must be carried out in accordance with the data quality objectives set out in Sections A and C of Annex I to Directive 2008/50/EC, and for the purposes of paragraph (5), measurements must also be carried out in accordance with the criteria set out in Annex IV to the same Directive.

(7) Save as provided for in paragraph (8), measurements for the purposes of this regulation must be taken in accordance with the reference measurement methods specified in Sections A and Section C of Annex VI to Directive 2008/50/EC.

(8) Alternative methods to those referred to in paragraph (7) may be used provided the conditions set out in Section B of that Annex are complied with.

(9) Where measurements are supplemented by modelling or indicative measurements the Scottish Ministers must take account of the results of those supplementary methods in assessing ambient air quality for the purposes of these Regulations.

(10) In this regulation, “chemical speciation concentrations” means the concentrations of different chemical components or species of PM_2.5.

Location and number of sampling points S

7.—(1) The Scottish Ministers must install sampling points in accordance with Schedule 1 for the assessment of sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter, 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 more 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 limit values and alert thresholds.

(3) In zones other than agglomerations where fixed measurement is 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 more 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 may be reduced by up to 50 per cent 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 or 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 to enable assessment results to meet the criteria in Section B of that Annex; and

(b) the number of sampling points in Section C of Annex V to Directive 2008/50/EC may be reduced by up to 50 per cent 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) For the measurement of PM_2.5 in rural background locations, the Scottish Ministers must install a sampling point for every 100,000km².