The research discovered that the damage was occurring twice as fast as on the Acropolis in Athens - which has come to epitomise the ravages of air pollution - and faster even than under experimental conditions where stone was exposed to high levels of sulphur dioxide.
Many of the city's most famous Victorian buildings are being eroded by the pollution. The gargoyles on Alfred Waterhouse's celebrated town hall are losing their sharpness, the stone of the Central Library is becoming mottled and eroded by dirt from car exhausts, and the Whitworth Art Gallery is also among those affected.
Manchester City Council, which is busily trying to build a new reputation for the fading industrial centre as an attractive conference venue, is reluctant to accept the study's findings, insisting that it has been reducing pollution in the city over recent years. But Richard Lewis, of the council's pollution monitoring group, says: "It is quite clear that there is erosion just by looking at the gargoyles on the Town Hall. You can see the damage to the sandstone."
And Councillor Kenneth Franklin, chairman of the city's environmental planning committee, added: "The architectural qualities of our buildings are there, but they are at risk because of pollution and the kind of stone that was used at the time they were built. We are concerned and are getting a team together to look at what measures need to be taken."
Manchester is not only one of the cradles of the Industrial Revolution, it is also the home of acid rain. It was first described there 143 years ago by the pioneering chemist, Robert Angus Smith, who coined the evocative phrase. Six years later he reported how "stones and bricks crumble more rapidly" due to "the slow, but constant, action of the acid rain" caused by the industrial pollution of the time.
Scientists now agree that the crumbling of Britain's historic buildings has accelerated over the last few decades even though emissions from factories have greatly declined. The main culprit is thought to be pollution from car exhausts.
The new study - carried out by scientists at Trinity College, Dublin, and financed by the EU - put hemispheres of sandstone, limestone and marble in Antwerp, Copenhagen, Athens, Dublin, Amsterdam, Manchester, in rural Donegal and on an experimental site at Liphook on the Sussex-Hampshire border, where they were deliberately exposed to high levels of sulphur dioxide. They then measured what happened to them over 20 months.
In Manchester the stones were placed on the roof of a building in the city centre which, the study says, "would have been subjected to pollution from traffic and office heating". In Athens they were exposed on the Acropolis where the four draped female statues (the caryatids) have been so badly damaged by air pollution that they have had to be replaced by replicas.
The study concludes: "The greatest loss of stone was recorded at Manchester." The only other places that recorded comparable - if lesser - damage were the experimental site at Liphook and in Antwerp. The rate of erosion was twice as bad in Manchester as at the Acropolis.
The city also came out twice as badly as Copenhagen, Dublin or Amsterdam - and was eroding three times as fast as Padua.
The leader of the study, Dr. Paul O'Brien - who has now started a consultancy to follow up the work - says that it confirms earlier research he co- ordinated in European cities which also found the greatest damage in Manchester. He says that the most harm is not done by acid rain itself (it was surprisingly dry in Manchester during the study period) but by sulphur dioxide pollution settling on the stones directly from the air and interreacting with the city's damp atmosphere.
The level of the pollution, he said, was higher in Manchester than anywhere else, except at Liphook where high levels were deliberately produced under carefully controlled conditions.Reuse content