New analysis by Professor Mike Pilling of Leeds University has shown that Chiswick High Road has become one of the twenty worst polluted spots in the capital. It joins places like the Cromwell Road, Marylebone Road and Shaftesbury Avenue on the list.

Chiswick's air quality seems to have undergone a rapid deterioration over the last year to 18 months against a trend of cleaner air elsewhere in the capital. More stringent emission standards and the scrapping of older more polluting buses have led to a general improvement.

Figures released by Hounslow Council earlier in the year showed Chiswick High Road having poorer air quality than the Cromwell Road after a dramatic deterioration during 2003 as measured by the concentration of nitrogen dioxide (NO2). This rose by an astonishing 43%.

The deterioration appears to be confirmed by Professor Pelling's observations which showed Chiswick High Road having 56 microgrammes of NO2 per cubic metre of air. The recommended safe limit is 40. Prof. Pelling believes that Chiswick's air quality will improve to around the safe limit by 2010.

In the absence of any official explanation for the specific deterioration in Chiswick there has been speculation as to why this particular area has been so badly affected. Theories include the impact of junction changes in and around Chiswick High Road, the increased number of buses, displaced traffic from the congestion charge zone, traffic calming and bus priority measures, the growth of Chiswick Business Park and even the growing number of 4x4s.

Transport for London's own numbers show that vehicular traffic in central London has been declining at a rate of 4% per annum since 1999 so the explanation is apparently not an increased number of cars on the road.

There are concerns that specific local factors may mean that the problem in Chiswick will continue to worsen. The extension of the congestion charge zone to Shepherd's Bush, the further expansion of Chiswick Business Park and the possibility of displaced traffic from the West London Transit System will all increase congestion in the area. Unlike many of the other areas currently on the list of those with the worst air quality, there are no significant improvements planned for the Chiswick area for at least the next decade.

We asked Transport for London to comment on this issue but are still awaiting their reply.

Nitrogen Dioxide Rates on Chiswick High Road

Source: London Borough of Hounslow