Commuters on public transport 'exposed to higher pollution levels'

Commuters using public transport are exposed to up to eight times more pollution than car users, research suggests.

Even though motorists produce the most pollution per commuter, they are the least exposed to harmful particulate matter as they are sealed off from the outside, the study by the University of Surrey found.

The team compared how commuters using cars, buses and the underground in different areas of London were exposed to a range of pollutants.

The study, published in the journal Environment International, found that commuters on some underground lines are the most exposed to poor air quality, followed by those on buses.

Monitors worn by commuters found those 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.

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. There is an interesting trade-off of pollution exposure between different modes of transport. For example, commuters travelling to work on underground trains are exposed to the highest levels of large-sized particles while being exposed to the highest level of black carbon and ultrafine particles during commute in buses. The relatively new airtight trains with closed windows showed a significant difference to the levels of particles people are exposed to over time, suggesting that operators should consider this aspect during any upgrade of underground trains, along with the ways to improve ventilation in underground tunnels.

Dr Prashant Kumar, University of Surrey