Self Sterilising Metals and Public Transport


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Last month, bacteriologists from Cornell University spent over a year travelling throughout the New York Subway swabbing seats, handrails, windows, walls and floors to see just how clean, or unclean, the subway actually is. Not only were their results predictably shocking but many of the microbes found were unfamiliar to science. Anthrax and the bubonic plague were amongst the bacteria recognised.

The simple fact that people aren’t dying off left right and centre supports the idea that this uncleanliness isn’t as harmful as the study suggests but what is apparent is that public transport does increase the risk of illness. We also know that there are self-sterilising materials which could be used in replacement of handrails.

Named the “oligodynamic effect” these materials can eradicate any single-cell organism that lands on them. Lots of different metals such as silver, lead or copper possess this trait.

The material’s effectiveness against bacteria is often dependent on the external conditions such as temperature and humidity. But even in the worst case scenario, e.g. a very dry summers day, above 20 degrees, you would still reduce bacteria count by 99.99 per cent within 30 minutes of contact. Which asks the question why has this not been implemented?

One of the main reasons is appearance. That doesn’t mean that they’re painted an illuminous colour to look good but so they stand out. This fits health and safety standards and more importantly aids the visually impaired due to the contrasting dark backgrounds. Painting any of the antibacterial materials would make them obsolete.

Another reason is the fact that the current handrails are made out of aluminum, which has a good ratio of weight to strength to cost, which is not the case with silver or copper. This asks the question, is it worth the cost installing the new self-sterilising materials? Simply put, no. More often than not, these surfaces are cleaned regularly throughout the day anyway.

Although we seem to be some distance away from self cleaning handrails and Tube poles every idea is worth debating and scrutinising until we find a better solution. Unfortunately, that solution isn’t lining our public transport with silver.