The RAC Foundation has said new research suggests that scrapping the oldest cars registered in urban areas would have a negligible effect on air quality.
Analysis of MOT information for 22 million cars has enabled a team of academics to use mileage, emissions and registered keeper data to map where the highest polluting vehicles are kept.
The RAC Foundation said it shows that vehicles responsible for emitting the most air pollution tend to be licensed at locations outside the most populous, relatively deprived urban areas, which are hardest hit by harmful emissions.
This applies on both a per kilometre and basis and annual basis, although the research highlights that the amount vehicles are used can be more important in determining their annual emissions than their per-kilometre emissions.
The most polluted areas tend to contain ‘older but cleaner cars’, the RAC Foundation said. Where older vehicles are registered in towns and cities they are likely to be driven less far and therefore produce, overall, relatively small amounts of nitrogen oxides, particulate matter and carbon dioxide.
Steve Gooding, director of the RAC Foundation, said: ‘The message is unmistakable. Targeting a scrappage scheme at the owners of old diesel cars in the most polluted areas is not going to get us where we need to be.
‘Scrappage might sound like a sensible quick fix, but the sad fact is that there is no easy solution to our air quality problems.
‘This report confirms that those on the lowest incomes are likely to have the oldest cars but reveals that more often than not they will be petrol rather than diesel. This probably reflects the fact that diesels only make up about a third of the total UK vehicle fleet and many of them will have been bought relatively recently by people thinking they were doing the environmentally-friendly thing.’
One of the report authors, Dr Tim Chatterton from the University of the West of England, Bristol, said: ‘It is time that UK air pollution policy stopped focussing solely on per-kilometre emissions from the vehicle fleet, and began to consider serious options for enabling less traffic on our urban roads.’