The scheme is drawing sharp criticism from scientists, but Johnson calls his fleet of three smog-busting trucks “wonderful contraptions.”
After the roads are swept and jet-washed following the evening rush hour, the trucks spray a solution of calcium and water on about 20 miles of London’s most polluted stretches of roadway.
Soot particles from exhaust, brakes and tires called PM10s stick to the film, allegedly helping to prevent asthma and other health problems, albeit in a very small area.
"As a health research scientist, I am just aghast that they are trying to hide the problem in this way," professor Frank Kelly of King’s College London told The Guardian.
The Green Party claims it's no coincidence that the one air monitoring station used by the mayor to report to the commission is on one of the routes being sprayed.
“They are cheating, making it look as if targets are being met when they are not with the use of this road glue,” said Jenny Jones, a Green member of the London Assembly.