http://www.nature.com/nsu/020624/020624-12.html

"Identifying which parts of a city's hustle and bustle contribute to global warming or other forms of atmospheric pollution is crucial to accurate climate modelling and policy-making."

"They found peaks of CO2 concentrations during rush-hour traffic, and from gas-powered heating for homes. They also identified the vast construction site for the new Scottish Parliament building in the east of the city as a major CO2 source."

"We need to know how much [of these pollutants] comes from each source to know how much effect our emissions controls are having,"

""Regional and global models need to take into account the nature of the urban environment," agrees Sue Grimmond, a meteorologist at Indiana University in Bloomington. Cities, she says, are growing and are where most of a region's greenhouse-gas emission is concentrated."

"Grimmond and colleagues are using eddy monitoring in other cities in Europe and North America. They find that, by day at least, cars are the most important source of CO2 in city centres. But surprisingly, they find that leafy suburban neighbourhoods - because of CO2-hungry plants - actually absorb more of the gas than they produce. "What is emerging from these studies is how diverse urban areas are," Grimmond says."