Polluting buses are set to be replaced with cleaner versions next month following years of campaigning for cleaner air in Putney.

Research found diesel buses accounted for more than two thirds of the high levels of Nitrogen Dioxide (NO2) emissions in Putney High Street, believed to cause heart problems.

Next month Transport for London (TfL) will start to replace the buses with cleaner models, following two years of campaigning by the Putney Society and a joint petition with Wandsworth Council.

There are currently 177 diesel buses using the high street, with 46 of the high polluting buses to be replaced in October.

TfL plans to use 10 low emission hybrid buses, while 85 of the diesel buses will be retrofitted with catalytic converters.

It is hoped the upgrade programme will be completed by March 2013.

The high level of pollution in the town is believed to be killing dozens of people prematurely and is likely to be contributing to cases of asthma, other respiratory conditions and heart disease.

A council air quality study found Putney High Street suffers from high levels of NO2, although fine particles (PM10) are within acceptable EU limits.

In January this year Putney was branded "a national disgrace" after it emerged levels of nitrogen dioxide (NO2) exceeded EU regulations 18 times. This was more high readings in a few weeks than is permitted for the whole year.

Councillor Jonathan Cook, executive member for the environment, said: "Buses are by far the greatest source of pollution on Putney High Street and these upgrades can't come soon enough.

"The council's air quality investigation is the only one of its kind in London and has pushed Putney right to the front of the queue for green bus funding.

"We built our case on solid scientific evidence and the result has been TfL prioritising investment in the local fleet."

The council said it will continue to fight for cleaner air in the borough, with proposals in place to help businesses reduce emissions and congestion caused by deliveries.

It is hoped the Barclays Cycle Hire Scheme and increased capacity on Putney trains will also help reduce the problem.

Visit wandsworth.gov.uk/airquality for more information