DEMiSt Study Suggests Ways to Reduce Diesel Fume Exposure

A King’s College London study of London taxi drivers, funded by the Institute of Occupational Safety and Health (IOSH), has found that drivers’ exposure to fossil fuel pollutants can be significantly reduced by adjusting vehicle ventilation settings. [i] This study is part of the wider Diesel Exhaust Mitigation Study (DEMiSt), which is investigating the effects of urban pollution on professional drivers. A key aim of the study is to devise ways that professional drivers can minimize harmful exposures.

The researchers studied 10 London Taxi drivers for 4 days. Half of the drivers used hybrid electric/petrol TXE City cabs and the other half used TX4 diesel powered vehicles. A monitor, worn by all drivers, measured their exposure to particulate carbon and nitrogen dioxide – both components of diesel exhaust fumes.

Results indicated fluctuating exposure levels throughout the working day; a combination of long periods of low exposure and intermittent short periods of high exposure. However, exposure was reduced by up to 67% when the taxi windows were closed and the ventilation systems were set to recycle interior air.

In addition, drivers of the older, diesel-powered cab were exposed, on average, to 1.8 times more nitrogen dioxide and black carbon than drivers of the newer, hybrid cabs.[ii] The researchers did not attribute this statistically significant difference to fuel type alone, however. The TXE City cab also benefits from an improved air tightness and ventilation system, reducing pollutant infiltration.

Duncan Spencer, head of advice and practice at IOSH, stated:

‘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’.

The complete findings of DEMiSt are expected to be published in 2019.


[i] Ventilation settings can limit driver diesel exposure.  IOSH Magazine. 8 October 2018. (Accessed 9 October 2018)

[ii] Vehicle choice could reduce drivers’ air pollution exposure. IOSH News. 5 October 2018. (Accessed 9 October 2018)