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Using physics to COVID-proof everyday life

Physics World January 2022

Physics World

 
News & Analysis Physics World  January 2022

Using physics to COVID-proof everyday life

Margaret Harris reports how physicists are using models and experimental techniques to get a better understanding of the transmission of viruses 

All lined up Ruixi Lou from the University of Massachusetts Amherst, US, has investigated the impact of aerosols when queuing. (Courtesy: University of Massachusetts Amherst)

The emergence of a new variant of the coronavirus SARS-COV-2 in November 2021 put virologists, immunologists and epidemiologists in the hot seat again as political leaders and public health experts sought to understand its transmissibility and by how much it erodes pre-existing immunity. But while attention for the moment is on the life sciences, physicists also have a role to play in stopping the virus that causes COVID-19. Indeed, in the longer term, insights from physics could drastically reduce transmission of other respiratory pathogens, too.

Such developments were highlighted at the annual meeting of the American Physical Society’s Division of Fluid Dynamics in November. The meeting featured work from Varghese Mathai from the University of Massachusetts Amherst in the US, who with Ruixi Lou and Devin Kenney had investigated the impact of aerosols when queuing. They placed cylindrical dummies some 2 m apart – a stand-in for queuing humans – and mounted them on a conveyor belt underwater. After filling an “infected” dummy with dye – representing virus-laden particles – they used a stepper motor to replicate the stop-start motion of people in a queue. Whenever the “queue” moved, each dummy ran straight into the cloud of dye emitted by the dummy in front of it, significantly reducing any benefit associated with distancing.

While people’s breath tends to rise after they exhale, the results still show that social distancing in queues is not a totally effective public health measure, even if the distance is doubled to 4 m. “In both cases, you see that the released dye particles end up right in front of the person behind you,” Mathai told a press briefing. “Waiting lines present a scenario where airborne transmission is possible.” 

Heading indoors 

If keeping your distance indoors isn’t possible, then wearing a mask is the best alternative. Biomedical fluids engineer Saikat Basu described how his team at South Dakota State University is developing a new type of mask inspired by the convoluted nasal passages of dogs and other animals that have an excellent sense of smell. The goal is to create a filter that is as effective as the material in a standard N95 mask, but much more breathable. “We are looking at a future where these respiratory pathogens will be more common,” Basu explains. Comfortable, effective masks are part of the solution, he adds, because people will be more inclined to wear them.

Rao Kotamarthi of Argonne National Laboratory told delegates that scientifically informed public health measures, better masks, and ventilation systems that don’t create “dead zones” of uncirculated air will all play a role in protecting people in future. The big question, though, is how long it will take to implement these solutions, and on that subject, Alfredo Soldati, a fluid mechanics expert at Technische Universität Wien, Austria, warned that, too often in the pandemic, “measures have been put in place where we could, not where we should”. Public health officials have a lot on their plates, but if they can spare some time to listen to their physics-trained colleagues, it could make their jobs – and all of our lives – much easier.