How new inventions can fight spread of COVID-19 indoors

WASHINGTON: It's become a familiar mantra: masks, hand-washing and physical distancing can slow the spread of the coronavirus while work continues on developing the vaccines and treatments needed to rid the world of its threat.

But as tens of millions of people return to public transit, their workplaces and schools, are these interventions enough?

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Researchers are increasingly looking at the pandemic through the lens of engineering, devising ways to make indoor environments safer. Here's a preview of what's in store.

HEATED NICKEL AIR FILTERS

Scientists are getting more worried about the potential airborne spread of the coronavirus, at distances far greater than the two meters of spacing urged by guidelines.

Certain super-spreading events, such as a choir practice in Washington state in the spring, appeared to involve so-called microdroplets that became suspended in the air.

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A technician applies an anti-microbial coating developed by Allied BioScience's first generation antimicrobial coating AFP/-

HEPA (high-efficiency particulate air) filters – technology that first came to market in the 1950s – are used widely in hospitals, biocontainment labs and airplanes. These use a fan to draw air through felt-like filters to capture the tiniest of microbes.

But the filters become contaminated over time and must eventually be incinerated or autoclaved.

A research team at the Texas Center for Superconductivity at University of Houston and Galveston National Laboratory has now demonstrated the efficiency of a new type of filter based on an ultra-fine foam made of nickel.

By heating the foam to 200 degrees Celsius, the researchers were able to eliminate 99.8 per cent of airborne SARS-CoV-2 virus from a room on first pass.

Crucially, the foam is insulated, so it doesn't heat up the room.

A scanning electron microscope image of SARS-CoV-2 (round blue objects) emerging from the surface of cells cultured in the lab AFP/Handout

The team published their findings in the journal Materials Today Physics last week, and Medistar – the company behind it – has received regulatory approval to sell the system.

The firm says the system can either be installed in pre-existing air conditioning units or walked through a room in a mobile unit.

"This is a very timely invention with great potential in fighting against COVID-19, particularly with increasing consensus that COVID-19 can be airborne," Gang Chen, an MIT professor who was not involved in the work, told AFP.

But since COVID-19 carriers may stay in a room for a prolonged period, the key to how useful any filtration system is lies in how fast it can exchange air at high volume.

NEW UV TECHNOLOGY

Lamps that operate on a particular area of the ultraviolet spectrum known as UVC have long been used to kill bacteria, viruses and molds, notably in hospitals and in the food-processing industry.

But direct exposure to UVC is dangerous because the rays, which aren't present in regular sunlight, cause skin cancer and eye problems – meaning they can only be used once people leave.

Researchers at Columbia University have been working for several years on a new type of UVC lamp, whose shorter wavelength of 222 nanometers makes them safe for humans but still lethal to microbes.

Last month, a team led by physicist David Brenner published a paper in the journal Scientific Reports showing that their technology killed 99.9 per cent of seasonal coronaviruses present in airborne droplets.

"We really need something in situations like offices, restaurants, airplanes, hospitals," Brenner told AFP.

Japanese company Ushio has already started selling far-UVC lamps in the US but says on its website that ongoing studies on their safety will decide when they are ready for occupied spaces.

A member of the cleaning staff disinfects air vents aboard an Emirates plane; the company Medistar says its new air filtration system based on heated nickel foam can be placed inside air conditioning systems or walked through a plane via a mobile unit AFP/-

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