Boris Johnson has spent £1.43m “gluing” pollution from vehicles to London’s roads using a method that air-quality experts have found does not work.

In 2010 Transport for London started a trial using dust suppressants – calcium magnesium acetate (CMA) – on some of the city’s dirtiest roads and industrial sites. The mayor said at the time it was a “wonderful contraption that tackles air quality head on” and that he expected it would have an immediate impact on air quality in the most polluted areas of central London. The process was extended into 2012 to tackle potential increases in pollution caused by the Olympic Games lanes.

But a study by scientists at King’s College London of the effectiveness of the glue at five major roads over the last two years showed it is ineffective at tackling PM10s – tiny particulates that have been shown to be harmful to human health – from car, van and lorry emissions. Most PM10 pollution is caused by traffic, in particular diesel fumes.

Benjamin Barratt, a lecturer in air quality science at King’s, said: “The bottom line is [the gluing method] is not going to work in many of the sites in London where the problem is purely down to traffic, but there are other locations in London where we have severe PM10 problems relating to industrial activity and it has been shown to have a role in those locations.”

A member of the mayor’s team said in 2011 that the scheme had cost £905,000 in its first year, and although the total cumulative cost has not been publicly available subsequently, it has been running since then.

Green party London assembly member Jenny Jones said: “Boris Johnson’s attempt at a quick fix of gluing pollution to London’s polluted highways such as Marylebone Road has proved to be a failure and a waste of taxpayers’ money.”

The finding comes as Johnson announced a package of measures to improve the capital’s air, which is among Europe’s worst. He called these new moves a “game-changing moment” – despite simultaneously watering down a pollution charging scheme.Johnson said London would establish an “ultra-low emission zone” to tackle air quality problems, but did not offer specific details as to what it would entail, other than outlining his “vision” that one day most or all cars in central London would be electric or hybrid vehicles.

“Creating the world’s first big-city ultra-low emission zone has the potential to be a game-changing moment in the quality of life of our great capital,” the mayor said. “My vision is a central zone where almost all the vehicles running during working hours are either zero- or low-emission. This would deliver incredible benefits in air quality and stimulate the delivery and mass use of low-emission technology.”

He said all buses in central London would use hybrid engines by 2020, zero-emission taxis would be encouraged and that he was giving £20m for London boroughs to address the worst pollution blackspots.

continue reading… Boris Johnson’s sticky pollution solution shown to be a £1.4m failure | Environment | The Guardian.