London Underground commuters most exposed to pollution

A study conducted by the University of Surrey has found that car drivers in London are causing the most pollution per commuter, but are least exposed to harmful particulate matter (PM), when compared with those taking public transport.

The research, published in Environment International, concluded that people travelling via the London Underground are the most exposed to poor air quality during their commutes to work, followed by those on buses.

It indicated that passengers on the District line in trains with closed windows were exposed to far lower concentrations of PM than those travelling on trains with open windows on the same line. PM levels were higher on trains on the Victoria and Northern lines, all of which had open windows, and in particular on trains travelling through tunnels.

The research did not find definitive evidence to suggest that those from more deprived areas were more exposed to pollution than those from less deprived areas. However, it did propose that people from areas with low deprivation have a predominant use of cars, receiving the lower doses while generating the largest emissions per person, while the opposite is observed for people from higher deprivation areas, who rely more on public transport.

Dr Prashant Kumar, leader of the study, explained: “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.”

Kumar added: “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.”