New research by Dr Anna Font and Dr Gary Fuller at King’s College London suggests that air pollution from London’s roads is improving overall but more work may be needed to tackle some sources of traffic pollution, which continue to breach limits in many parts of the city.

The study looked at trends in air pollution over a ten-year period spanning 2005 to 2014, using data collected from 65 roads. Researchers looked at changes in a number of pollutants including nitrogen dioxide (NO2), particulate matter as fine (PM2.5) and coarser (PM10) particles, carbon dioxide (CO2) and black carbon.

This new view of city-wide air pollution revealed significant variability across with some roads showing significant decreases but others did not improve. Examples include the notable improvement in nitrogen dioxide from traffic alongside Putney High Street and the deterioration along Upper Thames Street; the improvements in airborne particles on Marylebone Road in central London contrasting with the increase in coarse particles alongside some busy roads in outer London including Westhorne Avenue, part of the south circular in Eltham.

Since 2010 most roads showed some improvement in NO2 with an average decrease of five per cent per year but around three-quarters of roads still exceeded the NO2 EU Limit Value in 2015.

PM2.5 dropped after 2010 due to the exhaust abatement technologies such as particle filters on newer diesel vehicles. However, on some roads in outer London, such as Westhorne Avenue and Eltham that experienced decreases in PM2.5 but increased PM10. Alongside these roads the decrease in exhaust emissions may have been offset by greater releases of coarse particles from dust resuspension and wear-and-tear on tyres and brakes from larger number of heavy goods vehicles (HGVs).

Dr Gary Fuller, said: ‘It is great that evidence shows that policies are starting to have an impact, but we need to expand on these to reduce the health burden from breathing polluted air. Achieving the EU Limit Value for nitrogen dioxide by 2030 is likely to remain a challenge for many major roads in London.
‘Tighter management of HGVs needed to ensure that the greater number of vehicles on the road do not offset the benefits from pollution abatement. Non-exhaust traffic emissions appear to becoming more important sources of particulate matter and new policies may be needed to tackle them.’

‘Did policies to abate atmospheric emissions from traffic have a positive effect in London?’ is published in Environmental Pollution and is available online.

Photo by Connie Smith at Flickr

Item date 02/09/2016