London road-tests paving stones that 'eat' pollution

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The Independent Online

The streets of London may never be paved with gold, but they may soon be paved with stuff that sucks up pollution.

The streets of London may never be paved with gold, but they may soon be paved with stuff that sucks up pollution.

Westminster City Council is demonstrating its determination to improve air quality by becoming the first city in Europe to test a groundbreakingpollution-eating paving stone.

Pioneered by Japan's Mitsubishi Materials Corporation, the paving blocks break downpollution from car exhausts.They contain titanium dioxide, the council said yesterday, which uses sunlight to absorb harmful nitrogen oxides in the atmosphere and convert them into harmless nitrogen and oxygen. The chemical reaction works in both wet and dry conditions, it said.

The blocks have recently been tested in Osaka, Japan, the only city in the world currently using them. Westminster will be analysing the stones, looking particularly at issues of durability and area density, and discussing with Mitsubishi the potential for a trial in central London streets.

The stones could be laid as paving is renewed, the council said, at the rate of 10 to 20 miles a year. What the streets of Westminster - all 400 miles of them - are currently paved with is ASP or artificial square paving, a type of pre-cast concrete, which last about 20 years. Other materials include tarmac, block paving, mastic asphalt and York Stone.

"This is an innovative approach to the age-old problem of pollution, particularly on the kerbside," said Councillor Frixos Tombolis, vicechairman of Westminster's Transportation and Highways Committee. "These paving slabs serve a dual purpose: they effectively tackle a major urban pollutant and protect the environment without penalising drivers.

"I hope the tests prove to be successful, and that we will soon be seeing these pollution-busting paving stones, not just in Westminster, but across the country."

Don't build up your hopes too much, though. At the moment it's strictly oxides of nitrogen, and there is no evidence that pollution-busting paving can do anything about pizza crusts, chip wrappers, cigarette packets, Coke cans or dog mess.