A lack of fresh air was found in a deep London Underground station, and air pollution is at its worst during the evening rush hour, according to research led by the University of Surrey, which was conducted as part of the Engineering and Physical Sciences Research Council-funded INHALE project.
Surrey’s Global Centre for Clear Air Research (GCARE) collected airborne particulates on a deep-level (around 18 meters below ground) platform in South Kensington station. The results found that while the underground environment they tested was well within the limits set by the UK Health and Safety Executive, it exceeded the World Health Organization air quality guidelines for fine and coarse air pollution particles.
The pollution collected was analysed using an electron microscope by Imperial College London to test their makeup, which detected tiny amounts of ultrafine (100 nanometers or less) particles, including iron, manganese and traces of chromium and toxic organic matter.
Professor Prashant Kumar, study lead and Director of GCARE at the University of Surrey, said: “We accept that air pollution on platforms is a very complex problem to solve and that an effort is being made to clean the Underground during quieter periods. Our team points to the newly opened Elizabeth Line as an example of good practice – in particular, the use of a screen between the train and the platform to protect passengers from pollution caused by the trains.”
The monitoring and collection of particles took place on the eastbound Piccadilly Line platform at South Kensington station. It’s worth noting that the report describes the station as “relatively closed to outside air”, but it does in fact have ventilation provided from one of the old lift shafts that were taken out of use in the 1970s.
The team monitored air pollution at one platform in the station during operating hours (5 am until midnight) and non-operating hours. The study took place from September 2020 until October 2020 – that was just before the platforms closed for the escalator replacement work.
Professor Alex Porter from Imperial College London, who led the examination of the particles collected under the electron microscope, said: “Our research provides interesting preliminary evidence about the levels of pollution within one underground station. This is the first time the chemistry of the smallest particles, which can go deep into the lung and potentially damage cells, has been identified. Future research will help determine the potential health effects of such exposure.”