England (Commonwealth Union) – Increased environmental toxins have been causing disruption across the world, leading to health hazards as indicated by numerous studies. Densely populated cities are likely to have the most significant impact as they have fewer green spaces and increased vehicle movement. A new study by the University of Cambridge has revealed that the London Underground is polluted with ultrafine metallic particles tiny enough to move into the human bloodstream. The particle size is likely to make them unnoticed in surveys of pollution in the oldest metro system in the world.
The study was conducted with a new type of pollution evaluation, applying magnetism to monitor dust samples from Underground ticket halls, platforms and operator cabins. Researchers uncovered the samples having increased levels of the iron oxide known as maghemite. As its time consuming for iron to oxidize into maghemite, the results point in the direction that pollution particles are suspended for lengthy periods, as a result of poor ventilation throughout the Underground, particularly on station platforms. Certain particles are as tiny as 5 nanometers in diameter, which is tiny enough to breathe in and end up in the bloodstream, but too small to be captured by usual procedures of pollution monitoring. However, the risk to health is unclear.
“Since most of these air pollution particles are metallic, the Underground is an ideal place to test whether magnetism can be an effective way to monitor pollution,” explained senior author of the paper, Professor Richard Harrison from the University of Cambridge, Department of Earth Sciences. “Normally, we study magnetism as it relates to planets, but we decided to explore how those techniques could be applied to different areas, including air pollution.”
Researchers indicated that poor ventilation in the Underground, results in iron-rich dust suspending in the air as trains stop at platforms, further deteriorating air quality. As the suspended dust has magnetic properties, the researchers stated that an effective removal system may be magnetic filters in ventilation, cleaning of the tracks and tunnel walls, or placing screen doors between platforms and trains.