16th October 2018

How taxi drivers can reduce their exposure to harmful air pollutants

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Taxi drivers could reduce harmful air pollution exposure by up to 67 per cent by closing car windows and setting ventilation systems to recirculate interior air, according to a study.

The research, funded by IOSH (The Institution of Occupational Safety and Health) and conducted by King’s College London researchers, looked at the pollutants from diesel exhaust. It discovered that while levels of two major pollutants affecting London taxi drivers varied by the type of cab driven, it could be cut by more than two-thirds by setting the vehicles’ ventilation systems to recycle the air inside.

Shanon Lim, Dr Ben Barratt and Dr Ian Mudway of King’s College’s environmental research group studied ten London Taxi drivers who wore monitors to measure their exposure to particulate carbon and nitrogen dioxide (NO2) from diesel exhaust. The researchers say this discovery suggests “low cost changes could mitigate pollutant exposures for these drivers”.

NO2 and particulate carbon, which comes mainly from vehicle emissions, has been linked to thousands of premature deaths a year in the capital, following another study carried out by King’s College.

Breathing with prolonged exposure to NO2 affects lung functions, can inflame human airways and worsen asthma.

The average exposure to pollutants was twice as high when the drivers were at work and exposure levels varied during the working day, with long periods of low exposure with intermittent high spikes.

Duncan Spencer, IOSH’s head of advice and practice, said: “Although we’re generally becoming more aware of air quality and its impact on health, less well-known is the effect on professional drivers who spend more working hours on the road and the extent they are exposed to potentially harmful environments.

“This group often works within very congested urban environments and are often overlooked.”

The research focussed on two taxi models. Drivers of the older TX4 diesel powered cab were exposed to 1.8 times more NO2 and black carbon than those driving hybrid petrol/electric TXe City cabs, made by the London EV Company, co-sponsor of the research.

The study will contribute to the King’s College Driver Diesel Exposure Mitigation Study, funded by IOSH, which looks at urban pollution exposure to professional drivers for a range of occupations, vehicle types and driving conditions. A report is due next year.