The purpose of this report is to review air quality in London during the first quarter of 2001 and to report detailed measurement results for the year ending 31st March 2001.

The Croydon 6 and Richmond 5 monitoring sites joined the London Air Quality Network (LAQN) during the quarter.

Pollution during the first quarter of 2001 was dominated by widespread NO2 and PM10 incidents during the middle of January. Each of these episodes was caused by settled weather conditions and consequently poor pollution dispersion.

Measurements during the 12 months ending 31st March 2001 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 except Croydon 2. The annual mean NO2 objective was also exceeded at background and suburban locations in inner and west London.
• The incident based NO2 objective was exceeded at the kerbside sites Marylebone Road and Redbridge 2, and at the roadside site Kensington & Chelsea 3.
• The incident based PM10 objective was exceeded at the kerbside sites Marylebone Road and Rebridge 3, and the roadside sites Bexley 4, Enfield 2, Haringey 3, Hounslow 3 and Redbridge 4.
• The annual mean PM10 objective was exceeded at Marylebone Road and Enfield 2 only.
• The SO2 objective was not exceeded at any site.