Professional drivers face a greater risk of cancer because they are regularly being exposed to “hazardous” levels of diesel emissions at work.
This is according to Imperial College London’s Driver Diesel Exposure Mitigation Study (DEMiSt), which found professional drivers encountered black carbon exposures that were four times higher than their exposure at home.
All professional drivers examined as part of the study in and around London were exposed to high levels of black carbon, a component of diesel exhaust.
Taxi drivers experienced the highest level of exposure (6.6 μg/m3), followed by couriers (5.5 μg/m3) and waste removal drivers (4.3 μg/m3).
Some 11,500 hours of professional drivers’ exposure data were analysed. On average, 18.6% of their time was spent driving for work and this contributed 36.1% of total black carbon exposure. The 54.4% of their time spent at home only contributed 31.8% of total exposure to black carbon.
The drivers also experienced extremely high spikes in exposure to the substance, often exceeding 100 µg/m3 and lasting up to half an hour as it became trapped within their vehicle. This often happened in heavy traffic in central London; in areas where vehicles congregate, such as car parks and depots; and in streets between high buildings.
Dr Ian Mudway, who led the project said: “We know quite a lot about the dangers of exposure to traffic pollution. However, there has been surprisingly little research on levels of professional drivers’ exposure to pollution and its effects on their health
“We believe there are around a million people working in jobs like these in the UK alone, so this is a widespread and under-appreciated issue – indeed, it was very noticeable to us just how surprised drivers taking part in the study were at the levels of their exposure to diesel.”
The researchers recommended that exposure could be reduced in the following ways:
- driving with windows closed
- taking less congested routes and avoiding tunnels
- using recirculate ventilation settings (with windows closed), though only for short periods at times and in areas of high congestion
- shift rotation to reduce each driver’s exposure to peak traffic times
- changing to zero tailpipe emission vehicles with airtight cabins.
Commenting on the findings, British Occupational Hygiene Society president Kelvin Williams noted that measures taken by drivers to minimise Covid-19 exposure, such as opening windows or turning on external fan ventilation, may be heightening black carbon inhalation.
“In the short term, the study highlights the need for professional drivers to balance the risks of Covid-19 and diesel exhaust exposure insofar as possible. It is also of relevance to those working in buildings near busy roads who may be using natural ventilation as a Covid-19 control,” he said.
“In the longer term, it highlights the relationship between the general environment and sustainable workplace health protection. It suggests that professional drivers are likely to benefit most from less congestion, cleaner energy and better vehicle ventilation technology. Climate change measures can also have a direct benefit to all of our health.”