RESEARCHERS in Scotland have discovered a way to destroy discarded medical masks using air and electricity, in a development that could help cut harmful waste from hospitals and GP surgeries. 

The team at Heriot-Watt University in Edinburgh believe their approach could cut the use of incinerators if it can be scaled up.

The pioneering technique - known as a cold plasma system - uses around 200 watts of electricity, roughly the same as a PlayStation.

The system is mains-powered and creates a highly reactive environment which eventually converts the plastic face coverings into carbon dioxide and water.

The ear loops were more stubborn, however, and could only be degraded by nine per cent.

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Dr Humphrey Yiu, assistant professor at the university, said: "PPE from the healthcare sector has always been a waste challenge. It's high-volume and must be treated as biohazardous waste, which means it is incinerated.

"Incineration is expensive and not environmentally friendly - reaching the high temperatures required, over a long period of time, uses a lot of energy and generates a significant amount of pollutants.

"We proved that our small-scale, cold plasma system can degrade single-use face masks, the use of which has exploded since the pandemic. They are still widely used around the world.

"Our low power air plasma method efficiently degrades surgical masks in four hours, so that 90% of the mask is gone."

The team's findings have been reported in the academic journal Materials Degradation.

According to the World Health Organisation, by March 2020 it was estimated that healthcare professions were using around 89 million masks a month.

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In the same year, 3.4 billion single-use masks or face shields were thrown away every day, creating a mountain of waste.

Getting rid of the biohazard materials is also very expensive.

Before the pandemic, every tonne of medical waste cost around £450 to dispose of in the UK and $790 dollars (£635) in the United States.

Transportation of the materials from clinical settings to incineration sites also adds to harmful greenhouse gas emissions.

Professor Martin McCoustra, who specialises in complex surfaces research, said: "Plasma is already used to decontaminate surfaces as it destroys biological materials like bacteria and viruses as easily as any plastic.

"In this work, we've gone beyond simple decontamination to actually break down waste material by exposing the waste to the plasma for longer and at higher applied powers."

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Dr Yui said the focus now is scaling the system up to prove it could work at the hospital scale.

He said: "We'd like to develop models that could be installed in hospital wards or GP practice rooms, or work at the hospital scale, where hundreds of tons of PPE need to be destroyed."