Photocatalytic technology can be used on roads and buildings to effectively ‘eat’ excess levels of nitrogen dioxide and nitric oxide (NOx) in the air.

Marley Eternit currently manufactures its Ecologic range of tiles containing titanium dioxide which speeds up the naturally occurring nitrogen cycle.

The coating reacts with asthma-causing nitrogen oxides in the air to convert them to nitric acid, which is then neutralised to form calcium nitrate, a liquid fertiliser that is harmless to the environment.

Gavin White, product manager at Marley Eternit, said: “The UK is in breach of its air pollution targets in 16 areas, mainly busy cities.

“If it only addresses the polluter, rather than the pollution itself, then the UK is missing a trick.

“A better option is to take a two pronged approach and also look to reduce the amount of pollution that is still being produced with the use of photocatalytic technology on our buildings and roads to absorb the toxic mix of NOx generated by road traffic exhaust fumes.

“It sounds incredulous but the technology exists right now to use photocatalytic coatings on roof tiles to ‘eat’ pollution from the air but we are the only manufacturer that does it.

“We estimate that over the lifespan of an average sized roof, the amount of NOx the tiles will remove could be equivalent to that emitted by a modern car covering over 100,000 miles.”

The technology is already used in cement on pavements in countries such as Japan, America and the Netherlands to cut pollution at the roadside.

White said: “Using photocatalytic technology on just one roof has an impact on surrounding air pollution levels, but imagine the impact that thousands or millions of roofs could have.”