Taxi drivers exposed to highest levels of black carbon pollution

Taxi drivers working in congested cities experience the highest exposure to black carbon pollution compared with other professional drivers, such as couriers and truck drivers.

Shanon Lim (King’s College London, United Kingdom) explained during his presentation at the ERS congress that although there is a lot of knowledge on exposure to traffic pollution, hardly any data is available on the influence air pollutants have on professional drivers [1]. In the Diesel Exposure Mitigation Study, a collaboration between researchers at King’s College and researchers at Queen Mary University of London, 140 professional drivers from a range of occupations working in central London were recruited. In addition to taxi drivers, couriers, truck drivers, waste removal and emergency service workers took part in the trial. The drivers were asked to carry black carbon monitors for a period of 96 hours. The monitors measured exposure levels once every minute. Drivers were also asked about the type of vehicle they drive, their working hours, and whether they drive with their windows or air vents open.

On average, professional drivers were exposed to 4.1 µg/m³ of black carbon while driving, which was around 4 times higher than their exposure at home (1.1 µg/m³). Levels measured at home were similar to those experienced by office workers in big cities at their desks. From all the professional workers in the study, taxi drivers had the highest levels of exposure (on average 6.5 µg/m³), and emergency services workers the lowest levels of exposure (on average 2.8 µg/m³). However, all professional drivers experienced extremely high spikes in exposure to black carbon, often exceeding 100 µg/m3 and lasting up to half an hour.

As Mr Lim pointed out, the exposure levels of professional drivers were higher than those measured at a busy London roadside (3.1 µg/m³ on average at Marylebone Road). So, being inside a vehicle does not offer any protection from air pollution. On the contrary, air pollution seems to get trapped inside the vehicle for extended periods of time. However, the study showed a simple way to reduce exposure: keeping windows closed while working halved the levels of black carbon. The type of vehicle and the choice of route could also lower exposure.

As a next step, the researchers will investigate possible strategies to protect drivers, such as the use of air filters to minimise work-related health-risks.

1. 
   
   1. Lim G et al. Abstract OA486, ERS 2019, 29 Sept-2 Oct, Madrid, Spain.

 



Posted on 28 November, 201917 March, 2021