Air quality progress report raises doubts on NO2 standard

The Environment Department has given its strongest signal yet that it is looking for a relaxation of a problematic air quality standard for nitrogen dioxide.

In late November, DEFRA issued a consultation paper on the UK's report to the European Commission on progress towards standards set by the first air quality daughter Directive.1For the purposes of the Directive, the UK has been divided into 43 "zones and agglomerations". The report assesses the number of zones in 2001 which recorded an exceedence of the limit value plus a "margin of tolerance" which shrinks as the compliance year approaches.

The report confirms that the UK is currently off track in the following areas:

  • Nitrogen dioxide: The main problem concerns annual levels of NO2, where roadside exceedences have been measured or modelled in 21 zones. The hourly mean limit plus tolerance margin for NO2 was also exceeded at background sites in Greater London.

  • Particles: The annual and 24-hour limit values plus margins of tolerance for PM10 were both exceeded at roadside locations in Greater London.

  • Sulphur dioxide: The 24-hour limit value plus tolerance margin for sulphur dioxide was exceeded in Belfast. However, DEFRA is confident that the shift away from domestic coal burning should ensure compliance by 2005.

    DEFRA says that 122 local authorities have declared air quality management areas, the vast majority in respect of traffic-related NO2 and, to a less extent, PM10. It lists 49 authorities which have produced action plans, of which 22 are in London - but fails to mention moves to scrap air quality plans in many areas (see below).

    DEFRA also sees "an urgent need to address the question regarding the cost-benefit wisdom of reducing levels of NO2 in the relatively small number of 'hot spots'. It may be the case that actions to reach the limit values would be disproportionately expensive in a small number of cases." The comments reflect a growing debate about the health impacts of NO2 (ENDS Report 340, p 12 ).

    The report warns that "the ability of Member States to take further action to meet limit values is limited." It sees a "definite need" to explore further action at EU level to reduce emissions from traffic - and "to remove as far as possible the air quality disadvantages of diesel vehicles in comparison to petrol vehicles."

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