Diesel taxi drivers exposed to 1.8 times more pollution than those in an EV

London taxi drivers experience twice as much exposure to air pollution at the wheel compared to outside of work, but their choice of vehicle can make a very significant difference, according to a new study.

The study into air quality by King’s College London’s Environmental Research Group (ERG) and part funded by LEVC, monitored drivers of both diesel and electric taxis, measuring particulate matter and nitrogen dioxide inside and outside of their working environments. It found that drivers of diesel taxis are exposed to pollution levels 1.8 times higher than those driving an electric model.

Ten London taxi drivers were recruited and each cabbie was provided with a portable black carbon monitor (which is a proxy for diesel exhaust exposure) with an inbuilt GPS unit. This was supplemented by NO2 monitoring equipment. Five of the vehicles were LEVC TX models with the other half being TX4 diesels. The small sample size reflects the labour intensity required to undertake such research and is typical in personal exposure studies. Despite this, over 390 hours of taxi drivers’ air pollution data was analysed.

In-vehicle concentrations were measured over a period of four full working days during summer 2018. Initial analysis found that while cab drivers face the same level of exposure to poor air quality as other commercial vehicle drivers, and experience double the exposure at work compared to outside of work, their choice of vehicle made a very significant difference.

Average exposure to nitrogen dioxide and black carbon (a component of fine particulate matter – PM2.5 – which results from incomplete combustion of fossil fuel) during a standard shift was 1.8 times higher for drivers of the older diesel taxi compared to the all-new TX electric cab.

King’s College London hypothesise that the reduction in exposure for drivers in the TX electric cab isn’t down to the fuel type alone, but also due to the TX’s improved air tightness and ventilation system over the older model, reducing infiltration into the cab. Like many premium modern vehicles, the TX has a multi-filter system that works to remove gases and particles from the incoming air.