Air quality improvements around some London roads flatlined in the decade between 2005 and 2014 and in some areas even got worse, one of the most extensive environmental studies of its kind ever carried out suggests.
This is despite thousands of early deaths each year resulting from dirty air in the city – something described as a public health emergency by campaigners.
Academics Dr Gary Fuller and Dr Anna Font from King’s College London measured levels of pollutants like nitrogen dioxide (NO2), carbon dioxide (CO2) and various particles in the air around 65 traffic routes in the capital.
The pair found high levels of variability, with the air around some routes having improved over this time – though in other areas, air quality did not get better, and in some places it even went downhill.
For example, NO2 from traffic along Putney High Street improved thanks to what Dr Fuller said was an “intensive initiative to make things better” there, but there was a deterioration along Upper Thames Street in the City.
There were improvements in airborne particles on Marylebone Road in Westminster – a notoriously dirty stretch of the road network – but there was an increase in harmful particles swirling around in the air in some suburban areas in Ealing and Eltham.
Generally speaking, air quality did not improve between 2005 and 2010, but things started to get better in some areas after this time.
Perplexingly, changes in CO2 from 2010 onwards did not match downward predictions from reduced traffic flows and improved fleet efficiency, however.
CO2 was said to have increased along with increasing numbers of HGVs and buses.
Technology fitted to diesel exhausts of HGVs helped clean them up, the authors of the study concluded, but numbers of potentially dangerous particles from wear of tyres and breaks increased in areas with fast traffic flows such as the North Circular.
This study, entitled “Did policies to abate atmospheric emissions from traffic have a positive effect in London?”, was part funded by Transport for London and the Greater London Authority.
It concluded that heavy vehicles were “clearly an important factor” in urban air pollution.
And its authors wrote that, while increasing numbers of buses on the roads “might be desirable for many social and environmental reasons”, this would have to happen in conjunction with investment in cleaner emissions technologies.
They also recommended “greater management” of HGVs.
Launching the report, Dr 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 is 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.”
Various initiatives to try and improve London’s air have been ongoing since the 1990s.