Groundbreaking: Scientists create an air filter that kills the coronavirus

The coronavirus is spurring on all kinds of innovation and creativity from the scientific community as well as the business community. The main focus now is on developing a vaccine and therapeutic drugs to combat the virus. Businesses have shut down normal production of products and switched to manufacturing essential medical equipment, like ventilators, as well as personal protection equipment to meet the needs of hospitals and first responders. All of this is good.

Meanwhile, researchers at the University of Houston (UH) have developed an air filter that kills the coronavirus. It is a “catch and kill” filter and it sounds really promising. It traps the virus and other pathogens and instantly kills them. The researchers teamed up with others to make it happen. Zhifeng Ren, director of the Texas Center for Superconductivity at UH and Monzer Hourani, CEO of Medistar, a Houston-based medical real estate development firm, as well as other researchers, came together to design the filter. With just one pass through the filter, 99.8% of the germs were killed.

The researchers reported that virus tests at the Galveston National Laboratory found 99.8% of the novel SARS-CoV-2, the virus that causes COVID-19, was killed in a single pass through a filter made from commercially available nickel foam heated to 200 degrees Centigrade, or about 392 degrees Fahrenheit. It also killed 99.9% of the anthrax spores in testing at the national lab, which is run by the University of Texas Medical Branch.

Think of the possible uses for this filter. Schools, for instance, could more safely re-open if classrooms had these filters. Other places that Ren, MD Anderson Chair Professor of Physics at UH and the co-corresponding author for the paper published in Materials Today Physics, suggests are airports, airplanes, and cruise ships. Medistar executives also suggest building a desktop model to purify the air in an office worker’s immediate area.

Medistar approached the Texas Center for Superconductivity at the University of Houston in March for help in developing the filter. We know the virus is an airborne one that can potentially linger in the air for up to three hours. The filter can certainly act as a tool to mitigate the spread of the coronavirus in places where social distancing may not be very practical.

Researchers knew the virus doesn’t hold up in the heat – nothing above about 158 degrees Fahrenheit (70 degrees Centigrade) – so they decided to use a heated filter. They wanted to make the filter temperature hotter, at least 200 degrees Centigrade to instantly kill the germs. At first, they used nickel foam, then adjustments had to be made.

But nickel foam has low resistivity, making it difficult to raise the temperature high enough to quickly kill the virus. The researchers solved that problem by folding the foam, connecting multiple compartments with electrical wires to increase the resistance high enough to raise the temperature as high as 250 degrees C.

By making the filter electrically heated, rather than heating it from an external source, the researchers said they minimized the amount of heat that escaped from the filter, allowing air conditioning to function with minimal strain.

A prototype was built by a local workshop and first tested at Ren’s lab for the relationship between voltage/current and temperature; it then went to the Galveston lab to be tested for its ability to kill the virus. Ren said it satisfies the requirements for conventional heating, ventilation and air conditioning (HVAC) systems.

The part about heating up and interfering with air conditioning systems was what my concern was when I first read about it. In this part of the country, air conditioning is essential, and believe me, no one wants anything to interfere with it.

A phased-in rollout of the filter is called for by the creators. It makes sense that workers at elevated risk should get the filter first – hospital workers, health care facilities, schools, even public transportation environments like airplanes. These filters can allow workers additional protection from the germs that infect them with the virus and also allow people and school kids to get back to work and classes safely.

Protection from the airborne germs is even more important than hand washing and social distancing according to many scientists who are now asking the WHO and other public health organizations to adjust guidelines to emphasize the risk.

“Respiratory droplets are very large droplets that when you sneeze, for example, they shoot out of your mouth and they drop right to the ground because of gravity,” Dr. Ron Elfenbein, an emergency care physician, explained Monday on CBSN. “Whereas airborne means that the virus can hang out in the air for a long time and all you have to do is walk by a cloud of this and inhale it and you’re going to catch it.”

The smaller particles could spread by infected individuals simply breathing, laughing or talking, said Elfenbein, who said he agrees with the scientists behind the letter.

In some cases, those tiny particles called aerosols can travel up to 30 feet, and there’s concern they may play a significant role in the spread of COVID-19.

The scientists can argue among themselves how far the particles travel in the air but social distancing at six feet apart is difficult enough, 30 feet is impossibly impractical. The advice and guidelines continue to shift as scientists continue to learn more about the coronavirus. It’s frustrating and confusing to most of us how little the experts still know about the virus. This new filter is really encouraging, though, and sounds like it could be a real help in containing the spread of coronavirus germs.