Wearable Air Curtain Could Protect Workers From Pathogens

With the recent detection of the H5N1 bird flu in livestock, there is a pressing need to find ways to protect agricultural workers from this emerging and deadly virus. Historically, such workers would simply wear a paper mask to protect themselves. But if masks are not worn properly–which can be hard to do without fogging up protective goggles or when trying to communicate with other workers–they offer limited protection. 

“Even the best masks only work if you have a good seal to your face,” said Herek Clack, Ph.D., associate professor of civil and environmental engineering at the University of Michigan. “Most of the masks fit on the face using ear loops. But we don’t all have the same shape face, so you can’t guarantee a tight fit. And if you loosen the mask because you feel a little claustrophobic, or if you have a beard that gets in the way of that seal, or even if you just pull it down to talk to a coworker, it’s not giving you the protection you need.”

Even N95 masks, the gold standard in face masks used in healthcare settings to protect people from viruses, are not immune from these issues. To find a better way to protect people from airborne viruses, Clack and colleagues have developed a novel device that creates a sterilizing “air curtain” with the power to kill 99% of airborne viruses. What’s more, he and his team have demonstrated this level of efficacy in both the laboratory and in agricultural settings.

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Clack, a mechanical engineer by training, said the design of this novel device was inspired by his previous work trying to prevent coal ash being emitted into the atmosphere using a device called an electrostatic precipitator.

“It works on a principle of charging particles, essentially having those charged particles remove themselves from the exhaust gas flow,” he said. “It’s very old technology, but it provides a way to manipulate particles or aerosols that are charged so you can manage where they go.”

After moving to the University of Michigan, Clack started collaborating with fellow faculty member, Krista Rule Wigginton, Ph.D., whose research centered on how to remove viruses from drinking and wastewater. They started discussing new technologies that might allow them to manipulate airborne viruses using electric fields.

“We know that viruses can exist in air,” he said. “So, we wanted to develop ways to reduce the potential of those airborne viruses to cause or spread disease.”

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At the time, years before the COVID-19 pandemic, Clack said there was little interest in such a technology in the biomedical realm. But the agricultural industry, which fights different airborne pathogens each season, was very interested in finding a way to help prevent devastating illnesses in livestock. The culmination of that work led to this new “air curtain” device, which leverages the electrically charged molecules in nonthermal plasma to treat the air, killing the vast majority of viruses that may be present.

“The thing that makes our device distinctive from other technologies like EPI air filters or UV lights is that it is magnificently miniaturized,” said Clack. “We can make a very small device, treating a lot of air in a very small package. And we can make it wearable.”

Agricultural workers can put on a small backpack, not unlike a vacuum canister, which weighs about 10 pounds. Inside that canister, you will find a nonthermal plasma module, battery, electronics, and handler component that drags the surrounding air into the device. The air, after being treated by the nonthermal plasma to remove pathogens, is then directed through nozzles on the brim of a hardhat. Those nozzles push the decontaminated air across the face of the wearer, providing a safe “air curtain,” where viruses have been “inactivated” by the nonthermal plasma.

Clack and his colleagues at Taza Aya, a start-up which is working to commercialize the device, recently tested the “air curtain” at a Michigan turkey production plant.

Clack shared that such a device has the power to not only protect agricultural workers from potentially becoming infected by bird flu, but it can also help them from other dangerous viruses or aerosol particles. This will ultimately help keep disease transmission down–and agricultural plants avoid disruptions that could affect the country’s food supply chains. Clack said, in the future, it could also be used in other industry settings. 

As Taza Aya works to bring this unique device to market, Clack said he is in awe of the mechanical engineers who helped him create such a powerful product.

“The stuff that mechanical engineers can do, even working with such diverse subjects like microbiology, electrostatics, fluid mechanics, and electric fields, is amazing,” he said. “Mechanical engineers are among the few engineers that have a broad enough foundation in design that they could address the issues that we faced putting this solution together.”

Kayt Sukel is a technology writer in Houston.