The UK will spend 9.3 billion ($14.56 billion), according to Bloomberg, to build facilities for the Games, making it one of Europe's largest construction projects. But despite the huge spending, the authorities haven't done enough to improve London's air quality during the Olympics, says Kelly, whose KCL team runs 160 monitoring sites across the city and analyses data for the UK Department for Environment, Food and Rural Affairs.

London Mayor Boris Johnson, who is also a member of the Olympic Board that is overseeing the Games' planning, has said larger vans and minibuses will not be required to meet low-emission zone (LEZ) standards until January 2012. These vehicles were originally due to be included in the LEZ from October 2010 and would have had to pay fines for not meeting emission standards.

The former mayor of London, Ken Livingstone, introduced the LEZ in February 2008, which required large trucks, buses and minibuses to meet emission standards.

Johnson's cleanup plan includes buses powered by diesel-electric hybrid engines, banning older taxis and upgrading the public transport system. And his office has said that "the smooth running of London's Olympic Games will not be affected by poor air quality".

But Kelly is not so optimistic. If the weather is not good then there's a possibility that "we will have air pollution episodes". To improve the air quality, he suggests local authorities extend the LEZ and the government upgrade "all our buses and taxis as quickly as financially feasible".

But since the 2012 Olympics is less than two years away, London doesn't have enough time to accomplish the massive upgrade, he says. "Therefore, I think they'll have to consider having plans in place if the weather is not favorable and that will involve some kind of traffic regulation."

During the 2008 Games, Beijing authorities implemented tough measures, shifting polluting factories from the city to other places and restricting the number of cars on the roads by allowing drivers of vehicles with odd and even plate numbers to drive on alternate days.

Describing Beijing's measures a "successful scheme", Kelly says regulating traffic, the main source of London's air pollution, would be a useful way to improve the city's air quality during the 2012 Games. "(If) you don't have vehicles, you don't have pollution in London. That is very simple," he says.

"The last thing we want is very bad weather and not have any controls in place, and end up with headlines saying: 'Pollution concentration in London exceeds the European guidelines, WHO levels'. That will not be good publicity for London."

To have "controls in place" for eventualities, Kelly hopes that London officials would talk to their Beijing counterparts "who implemented those successful schemes". This sure is taking a green leaf out of Beijing's book on its Olympic chapter.

The author is a European correspondent of China Daily.