The purpose of this report is to review air quality in London during the 3rd quarter of 2002 and to report detailed measurement results for the year ending 30th September 2002.

During the quarter 2 new monitoring sites joined the London Air Quality Network.

Widespread ‘high’ O3 was measured in London during late July 2002.

Measurements during the 12 months ending 30th September 2002 have been compared to the Air Quality Strategy (AQS) Objectives:

• The Redbridge 2 kerbside site exceeded the CO objective.
• The annual mean NO2 objective was exceeded at all kerbside and roadside measurement sites. This objective was also exceeded at background locations in inner London and at sites in West London; the Hillingdon AURN site, Heathrow Airport and Hounslow 2.
• The incident based NO2 objective was exceeded at the kerbside site Redbridge 2, and at the roadside site Kensington & Chelsea 3.
• Widespread exceedences of the O3 objective were measured in outer London and at sites in the Home Counties.
• The incident based PM10 objective was exceeded at several near road sites; the kerbside sites Barnet 1, Marylebone Road and Redbridge 3, and the roadside sites Bexley 4, Brent 2, Enfield 2, Enfield 4, Hounslow 3, Lambeth 1, Lambeth 2 and Redbridge 4.
• The annual mean PM10 objective was exceeded at Bexley 4, Enfield 4 and Marylebone Road.
• The SO2 objective was not exceeded at any LAQN site.