The Air Quality Standards Regulations (Northern Ireland) 2010 No. 188

SCHEDULE 1 Sampling points for measurement of sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter, lead, benzene and carbon monoxide in ambient air

PART 2 Macroscale siting of sampling points

Sampling points for the protection of human health

5.  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.