‘SMOG stoppers’ could improve the air quality for Prestwich, Whitefield and Simister residents.

The Highways Agency is set to spend £2.5 million putting up the special 4ft walls by the side of the road near Simister Island – junction 18 of the M62 – in September in the hope that they disperse vehicle emissions.

Transport chiefs will spend a year monitoring if the walls work and the project could be expanded if so.

A Highways Agency spokesman said: “The barriers, which have been trialled in other European countries, work by dispersing emissions and can act as an effective safeguard to communities near busy roads.

“The results of international studies so far show the barriers can reduce the level of oxides of nitrogen by up to 20 per cent in some areas.

“If successful, the barriers could shape the future design of other major road schemes where air pollution exceeds legal thresholds.”

The wooden barriers will be 100m long and 4m high in most places and 6m high in other areas.

State-of-the-art air quality monitoring equipment will be placed near the barriers.

Highways Agency senior project manager Jacqui Allen said: “We need to ensure that whilst government spending to improve England’s road network is tripling to over £3 billion by 2021, it is vital we also look after our environment.

“This pilot will provide us with more evidence as to whether these barriers can be effective, and is just one part of our research to find new ways of dispersing harmful emissions.”