The study, led by Professor Frank Kelly of King’s College London is part of HEI’s research program to measure the possible health outcomes associated with actions taken to improve air quality. The HEI’s Review Committee concluded that Kelly and colleagues’ investigation represents a creative effort to explore a subtle change in air quality associated with a complex intervention to reduce traffic congestion. Although they were unable to demonstrate a clear effect of the CCS either on individual air pollutant levels or on oxidative potential of particulate matter, their study offers many lessons for future studies of interventions that are expected to influence air quality.

Dan Greenbaum, HEI’s President said "The Congestion Charging Scheme was one of the first to be implemented in a major city in Europe or the US and did show measurable reductions in traffic volume but air pollution does not know precise boundaries so any benefit of the CCS or air quality appears to have been lost in the larger regional pollution mix."

Professor Frank Kelly from the Environmental Research Group at King’s College London, said:"The London Congestion Charging Scheme was a world leading traffic intervention aimed at controlling excessive vehicle flows in central London. The findings reported in this HEI study will be of use to other administrations considering introducing traffic management schemes so that they can achieve vehicle reductions as well as improving air quality at the same time."

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Item date 27/04/2011