Directive 2008/50/EC of the European Parliament and of the CouncilShow full title

C. Microscale siting of sampling points

In so far as is practicable, the following shall apply:

• the flow around the inlet sampling probe shall be unrestricted (free in an arc of at least 270°) without any obstructions affecting the airflow in the vicinity of the sampler (normally some metres away from buildings, balconies, trees and other obstacles and at least 0,5 m from the nearest building in the case of sampling points representing air quality at the building line),

• in general, the inlet sampling point shall be between 1,5 m (the breathing zone) and 4 m above the ground. Higher positions (up to 8 m) may be necessary in some circumstances. Higher siting may also be appropriate if the station is representative of a large area,

• the inlet probe shall not be positioned in the immediate vicinity of sources in order to avoid the direct intake of emissions unmixed with ambient air,

• the sampler's exhaust outlet shall be positioned so that recirculation of exhaust air to the sampler inlet is avoided,

• for all pollutants, traffic-orientated sampling probes shall be at least 25 m from the edge of major junctions and no more than 10 m from the kerbside.,

The following factors may also be taken into account:

• interfering sources,

• security,

• access,

• availability of electrical power and telephone communications,

• visibility of the site in relation to its surroundings,

• safety of the public and operators,

• the desirability of co-locating sampling points for different pollutants,

• planning requirements.,