The report, for the British Lung Foundation (BLF), concludes that "vehicle users pay only around a third of the costs that they impose on society." It was prepared by a group of noted environmental economists, led by David Pearce of the Centre for Social and Economic Research on the Global Environment. It is mostly a rehash of earlier work, notably Professor Pearce's 1996 book Blueprint 5: The True Costs of Road Transport.
The study uses the "willingness to pay" approach in which questionnaires are used to assess how much members of the public would pay to avoid an adverse outcome such as premature death. The economists derived a £2 million "value of a statistical life", roughly twice that used in official appraisals of the benefits of road construction projects.
Numbers of pollution-related deaths, hospital admissions and respiratory illnesses were estimated, mainly from overseas studies. Overall costs were then calculated by multiplying each "illness event" by the "willingness to pay" to avoid it.
Professor Pearce concludes that the health costs of pollution are £11 billion annually, split evenly between premature deaths and illness. He then throws in conclusions from earlier work which calculated the total environmental costs of road transport at £46-53 billion - the figure used to support the claim that motorists only pay a third of their costs. Other studies cited by the Royal Commission on Environmental Pollution produced much lower figures (ENDS Report 272, pp 11-12 ).
Professor John Ayres, a leading specialist on the health effects of air pollution, told ENDS that the conclusions were "nonsense". Professor Ayres led work by a DoH committee which recently concluded that air pollution may cause 12,000-24,000 deaths in the UK (ENDS Report 276, pp 4-5 ) - considerably more than the 3,000 estimated by the BLF report.
The committee found, however, that most health impacts occur in individuals with severe pre-existing disease, and that most deaths are brought forward by only a few days or weeks. The BLF report takes no account of this "harvesting" effect.
"Any methodology which puts the same cost on the death of a healthy 20-year-old and that of an 83-year-old who dies a day early is very suspect," Professor Ayres commented.
Moreover, the DoH committee felt unable to quantify less severe health effects because of a lack of UK data. "It's crazy even to try and assess the costs without a proper basis for quantification [of effects]," Professor Ayres says. Health Secretary Frank Dobson has also warned that uncertainties in the effects of air pollution make costings "wildly difficult".
Nevertheless, the DoH itself has set up an expert group to appraise the costs and benefits of reducing air pollution. The group is still discussing whether to use "willingness to pay" methodology. Its work will inform the Government's air quality strategy review (ENDS Report 270, pp 34-35 ).