Bus and tube users exposed to 'up to eight times' more pollution than car users

A new study has revealed that although motorists produce the most pollution per commuter, being sealed inside their cars means they are the least exposed to harmful particulate matter (PM) from the outside.

Experts at the University of Surrey compared how commuters using cars, buses and the underground in different parts of London were exposed to a range of pollutants.

Figures showed that passengers on underground trains with opening windows were exposed to the worst air quality, followed by those on buses.

Above ground, bus travellers were found to be exposed to higher levels of black carbon and particles than car users.

Dr Prashant Kumar, who led the study, said: "We found that there is definitely an element of environmental injustice among those commuting in London, with those who create the most pollution having the least exposure to it."

The latest study involved commuters wearing air pollution monitors as they undertook hundreds of journeys by car, bus and tube.

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They found people on the tube were exposed to 68 micrograms of PM10 - tiny particles of soot that are breathed into the lungs - compared to eight micrograms of exposure experienced by motorists.

Levels of PM2.5 fine particles, which can be more lethal as they are drawn deep into the lungs, were twice as high on buses as in cars.

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The study did not find conclusive evidence to link deprived areas with higher exposure, but found that people from affluent areas tend to breathe in less pollutants because more people use cars.

"There is an interesting trade-off of pollution exposure between different modes of transport," said Dr Kumar.

Drivers commuting in diesel cars produced the most pollutants, the study found.

London Mayor Sadiq Khan is due to introduce a £10 daily "toxicity charge" on diesel cars made before 2005 which travel into central London.

And he has called for a national scrappage scheme to encourage diesel drivers to buy cleaner cars.

The latest findings are being published in the journal Environment International.