14 DAY TRIAL // Researchers have discovered that your level of exposure to pollution can vary according to what method of transport you use, with traveling by taxis resulting in the highest levels of exposure and walking the least.
Research published in the journal Atmospheric Environment describes how the team from Imperial College London and the Health and Safety Laboratory, Buxton, measured and visualized exposure to pollution levels, while using a variety of different transport methods for traveling across London.
The researchers looked at five modes of transport, including walking, cycling, car, taxi and bus, and measured levels of exposure to ultrafine particles when traveling on them using a newly developed system that uses in combination an ultrafine particle counter and video recorder.
Ultrafine particles are less than 100 nanometers in diameter and mainly traffic related. Their small size and large surface area means it is possible to inhale large quantities which makes them particularly dangerous.
On average, while traveling in a taxi, passengers were exposed to over 100,000 ultrafine particles counts per cubic centimeter (pt/cm3), traveling in a bus resulted in exposure to just under 100,000 pt/cm3, traveling in car caused exposure to 40,000 pt/cm3, cycling was around 8,000 pt/cm3, and walking was just under 5,000 pt/cm3.
Surbjit Kaur, from Imperial College London, and first author of the paper, said: "It was a real surprise to find the extent to which walking resulted in the lowest exposure. The higher exposure from traveling in taxis may come from actually sitting in the vehicle while being stuck in traffic where you are directly in the path of the pollutant source. Also the fact that taxis are probably on the road for much longer than your average car could cause an accumulation of ultrafine particles."