The Air Quality Standards (Scotland) Regulations 2010

PART 2 S Assessment of ambient air quality

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.

CHAPTER 2 S Ozone

Assessment criteria S

8.—(1) The Scottish Ministers must assess the level of ozone in ambient air in all zones.

(2) The Scottish Ministers must ensure that fixed measurements are taken in any zone where concentrations of ozone have exceeded the long-term objectives specified in Schedule 4 during any of the five years preceding those measurements.

(3) For the purposes of paragraph (1), 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.

(4) Save as provided for in paragraph (5), for the purposes of paragraph (2), measurements must be taken in accordance with the reference measurement method specified in point 8 of Section A of Annex VI to Directive 2008/50/EC.

(5) Alternative methods to that referred to in paragraph (4) may be used provided the conditions set out in Section B of that Annex are complied with.

(6) Where fixed 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.

Location and number of sampling points S

9.—(1) The Scottish Ministers must install sampling points in accordance with the criteria set out in Annex VIII to Directive 2008/50/EC.

(2) In zones where fixed measurement is the sole source of information for the assessment of air quality, the number of sampling points must be more than or equal to the minimum number specified in Section A of Annex IX to Directive 2008/50/EC.

(3) In zones where concentrations of ozone have been below the long-term objectives for each of the previous five years of measurement, the number of sampling points must be determined in accordance with the criteria set out in Section B of Annex IX to Directive 2008/50/EC.

(4) In zones where the information from fixed measurements is supplemented by information from modelling or indicative measurements or both, the number of sampling points referred to in paragraph (2) may be reduced provided that the following conditions are met:—

(a) the supplementary methods provide sufficient information for the assessment of air quality in relation to target values, long-term objectives, information and alert thresholds;

(b) the number of sampling points to be installed and the spatial resolution of supplementary methods are sufficient for the concentration of ozone to be established in accordance with the data quality objectives set out in Section A of Annex I to Directive 2008/50/EC and to enable assessment results to meet the criteria specified in Section B of the same Annex;

(c) there is at least one sampling point in each zone, with a minimum of one sampling point per two million inhabitants or one sampling point per 50,000km², whichever produces the greater number of sampling points; and

(d) nitrogen dioxide is measured at all remaining sampling points except at rural background stations as referred to in Section A of Annex VIII to Directive 2008/50/EC.

(5) The Scottish Ministers must ensure that nitrogen dioxide is measured at no less than 50 per cent of the sampling points required under Section A of Annex IX to Directive 2008/50/EC.

(6) The measurement referred to in paragraph (5) must be continuous except at rural background stations.

(7) In choosing the location and number of sampling points for measurements of ozone precursor substances, the Scottish Ministers must take into account the objectives and methods set out in Annex X to Directive 2008/50/EC.

CHAPTER 3 S Arsenic, cadmium, nickel, mercury, benzo(a)pyrene and other polycyclic aromatic hydrocarbons

Assessment thresholds S

10.—(1) The Scottish Ministers must classify each zone according to whether or not the upper and lower assessment thresholds specified in Section I of Annex II to Directive 2004/107/EC are exceeded in relation to arsenic, cadmium, nickel and benzo(a)pyrene.

(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 the pollutants referred to in paragraph (1) in ambient air.

(3) When considering the classification of zones in accordance with assessment thresholds, the Scottish Ministers must comply with Section II of Annex II to Directive 2004/107/EC.

Assessment criteria S

11.—(1) The Scottish Ministers must assess concentrations of arsenic, cadmium, nickel and benzo(a)pyrene in ambient air in all zones.

(2) In zones where the level of any pollutant mentioned in paragraph (1) is above the upper assessment threshold for that pollutant, fixed measurements must be used in relation to that pollutant but may be supplemented by modelling techniques to provide an adequate level of information on ambient air quality.

(3) In zones where the level of any pollutant mentioned in paragraph (1) is above the lower assessment threshold but below the upper assessment threshold for that pollutant, fixed measurements must be used in relation to that pollutant but may be supplemented by indicative measurements as referred to in Section I of Annex IV to Directive 2004/107/EC or modelling, or both, to assess the level of these pollutants in ambient air.

(4) In zones where the level of any pollutant mentioned in paragraph (1) is below the lower assessment threshold for that pollutant, modelling or objective estimation techniques may be used instead of measurement in relation to that pollutant.

Location and number of sampling points S

12.  The Scottish Ministers must determine the location and number of sampling points for the assessment of arsenic, cadmium, nickel and benzo(a)pyrene in accordance with Annex III to Directive 2004/107/EC.

Monitoring of polycyclic aromatic hydrocarbons S

13.—(1) The Scottish Ministers must monitor concentrations of other relevant polycyclic aromatic hydrocarbons in addition to benzo(a)pyrene as they think fit, including at least the following:—

(a) benzo(a)anthracene;

(b) benzo(b)fluoranthene;

(c) benzo(j)fluoranthene;

(d) benzo(k)fluoranthene;

(e) indeno(1,2,3-cd)pyrene; and

(f) dibenz(a,h)anthracene.

(2) Monitoring sites must be located together with sampling points for benzo(a)pyrene.

(3) Monitoring sites must be selected so that geographical variations and long term trends in the concentrations of polycyclic aromatic hydrocarbons can be identified.

(4) Monitoring sites must be selected in accordance with the criteria in Sections I to III of Annex III to Directive 2004/107/EC.

Background monitoring S

14.—(1) The Scottish Ministers must operate background sampling points to provide the indicative measurements of—

(a) concentrations of—

(i) arsenic, cadmium, nickel and benzo(a)pyrene;

(ii) the polycyclic aromatic hydrocarbons referred to in paragraph (1) of regulation 13;

(iii) total gaseous mercury.

(b) total depositions of—

(i) arsenic, cadmium, nickel and benzo(a)pyrene within the PM₁₀ fraction;

(ii) the polycyclic aromatic hydrocarbons referred to in paragraph (1) of regulation 13;

(iii) mercury.

(2) For the purposes of paragraph (1) the Scottish Ministers must ensure that—

(a) at least one sampling point is installed for every 100,000 km² ; and

(b) each sampling point is located in accordance with Sections I to III of Annex III to Directive 2004/107/EC.

Data quality objectives S

15.  When assessing levels of arsenic, cadmium, nickel, benzo(a)pyrene and other polycyclic aromatic hydrocarbons and total gaseous mercury, the Scottish Ministers must apply the data quality objectives and other standards contained in Annex IV to Directive 2004/107/EC.

Reference methods for sampling and analysis S

16.  Measurements of arsenic, cadmium, mercury, nickel, benzo(a)pyrene and other polycyclic aromatic hydrocarbons in ambient air and deposition of those pollutants must be made in accordance with the reference methods set out in Annex V to Directive 2004/107/EC.