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SCHEDULE 6 continued PART 2
6. The sites of sampling points shall be selected in such a way as to provide data on—
(a) the areas within zones where the population is likely to be directly or indirectly exposed to the highest concentrations averaged over a calendar year;
(b) concentrations in other areas within zones which are representative of the exposure of the general population;
(c) deposition rates representing the indirect exposure of the population through the food chain.
7. Sampling points shall in general be sited so as to avoid measuring very small micro-environments in their immediate vicinity. Where possible, the Secretary of State shall locate sampling points so as to be representative of air quality in surrounding areas of no less than 200 m² at traffic-orientated sites, at least 250 m × 250 m at industrial sites, where feasible, and several square kilometres at urban-background sites.
8. Where the objective is to assess background levels the sampling site shall not be influenced by agglomerations or industrial sites in its vicinity, i.e. sites closer than a few kilometres (as the Secretary of State may determine in light of the circumstances of each case).
9. Where contributions from industrial sources are to be assessed, at least one sampling point shall be installed downwind of the source in the nearest residential area. Where the background concentration is not known, an additional sampling point shall be situated within the main wind direction. In particular in cases falling within regulation 9(1)(a), the sampling points shall be sited such that the application of the measures referred to at regulation 7(2)(b) can be monitored.
10. Sampling points shall also, where possible, be representative of similar locations not in their immediate vicinity. Where appropriate they shall be co-located with sampling points for PM10.
11. Sampling points for ozone shall be located in accordance with the considerations set out in the following table—
(1)
Sampling points shall also, where possible, be representative of similar locations not in their immediate vicinity. |
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| Type of station | Objective of measurement | Representativeness(1) | Macroscale siting criteria |
|---|---|---|---|
| Urban | Protection of human health: to assess the exposure of the urban population to ozone, i.e. where the population density and ozone concentration are relatively high and representative of the exposure of the general population | A few km2 | Away from the influence of local emissions such as traffic, petrol stations etc; vented locations where the urban population to well mixed levels can be measured; locations such as residential and commercial areas of cities, parks (away from the trees), big streets or squares with very little or no traffic open areas characteristic of education, sports or recreation facilities |
| Suburban | Protection of human health and vegetation: to assess the exposure of the population and vegetation located in the outskirts of the agglomeration, where the highest ozone levels, to which the population and vegetation is likely to be directly or indirectly exposed, occur | Some tens of km2 | At a certain distance from the area of maximum emissions, downwind following the main wind direction during conditions favourable to ozone formation; where population, sensitive crops or natural ecosystems located in the outer fringe of an agglomeration are exposed to high ozone levels; where appropriate, some sub urban stations also upwind of the area of maximum emissions, in order to determine the regional background levels of ozone |
| Rural | Protection of human health and vegetation: to assess the exposure of population, crops and natural ecosystems to sub-regional scale ozone concentrations | Sub-regional levels (a few km2) | Stations can be located in small settlements and/or areas with natural ecosystems, forests or crops; representative for ozone away from the influence of immediate local emissions such as industrial installations and roads; at open area sites, but not on higher mountain-tops |
| Rural background | Protection of vegetation and human health: to assess the exposure of crops and natural ecosystems to regional-scale ozone concentrations as well as exposure of the populations | Regional/national/continental levels (1,000 to 10,000 km2) | Station located in areas with lower population density, e.g. with natural ecosystems, forests, far removed from urban and industrial areas and away from local emissions; avoid locations which are subject to locally enhanced formation of near-ground inversion conditions, also summits of higher mountains; coastal sites with pronounced diurnal wind cycles of local character are not recommended by Directive 2002/3/EC |
12. For rural and rural background stations, consideration shall be given, where appropriate, to co-ordination with the monitoring requirements of Commission Regulation 1091/94(18) concerning protection of the Community’s forests against atmospheric pollution.
OJ No L 125, 18.05.94, p.1. Back [18]
The Air Quality Standards Regulations 2007