New research from King’s College London’s Environmental Research Group has suggested that drivers of diesel taxis are exposed to levels of air pollutants up to two times higher than those using electric-enabled models.
The research, part funded by the developer of the TX eCity range-extended taxi, LEVC, saw ten cabbies provided with portable black carbon monitors and NO2 monitoring equipment. Five of the vehicles were newer TX models with the other half being TX4 diesels.
Over 390 hours of taxi drivers’ air pollution data was analysed, suggesting that exposure to nitrogen dioxide and black carbon during a standard shift was 1.8 times higher for drivers of the older diesel taxi compared to the newer vehicle.
It is thought that the improvements are partly down to the fuel type, as well as potentially being aided by improved ventilation in the newer models.
The researchers have also sought to highlight that simple driver behaviours can also play a significant role in cutting air pollution exposure.
Lead researcher Dr Benjamin Barratt of King’s College London said: “Lowest pollutant exposures were observed – particularly in the case of the TX – when the vehicle’s ventilation settings were set to recirculate and with the vehicle’s windows closed. This combination was found to reduce exposure by up to 67%, suggesting that these changes could mitigate pollutant exposures for these drivers.
“For the older vehicle, we believe that the vehicle’s cabin is not as air tight and therefore allows outside traffic emissions to infiltrate the cabin, even when the windows are closed.”
The study forms a portion of the wider DEMiSt research project funded by the Institution of Occupational Safety and Health (IOSH), which aims to understand the determinants of urban pollution exposure to professional drivers for a range of occupations, vehicle types and driving conditions.
The programme also seeks to understand whether there are certain behaviours professional drivers can adopt to minimise their exposure to air pollution.
Duncan Spencer, Head of Advice and Practice at IOSH, said: “One priority area of activity for IOSH is working to prevent occupational cancer, and very fine particulate matter in diesel engine exhaust emissions can be carcinogenic. This research focusing on taxi drivers forms part of our two-year DEMiSt ‘Diesel Exposure Mitigation Study’.”
The project also aims to understand the risk of harm to professional drivers from exposure to diesel exhaust emissions so practical risk reduction strategies can be developed and implemented.
The researchers are currently recruiting 200 professional drivers of taxis, vans and trucks from across a range of sectors to be monitored for this research.
More detailed advice on how professional drivers can minimise their exposure to air pollution will be produced upon completion of the full IOSH study, which is expected in 2019.