Question to the Department for Transport:

To ask the Secretary of State for Transport, how many air pollution monitors there are in which location within Heathrow Airport's perimeter from which official data on air quality is collected.

Heathrow Airport Ltd (HAL) has monitored air quality since 1993 at its site located near the northern runway (LHR2), however this does not provide official data for Defra’s national air quality monitoring network - The Automatic Urban and Rural Network (AURN).

Heathrow also now monitors air quality at three other sites around the airport — Harlington, Longford (Green Gates) and Stanwell (Oaks Road). The Harlington site is included within AURN.

Further information is available on the Heathrow Airwatch website at: http://www.heathrowairwatch.org.uk/