By Mark Wilson

You should practice social distancing and wear a mask to prevent the spread of COVID-19. But even masks aren’t perfect. A high-end N95 mask can filter an estimated 99.8% of the virus from the air, while many cotton masks filter just 50% or less. Given that researchers now know the virus is airborne, you may wonder: Is there anything else you can do to prevent the spread of COVID-19?

According to David Edwards, a Harvard professor and entrepreneur, there is. And it’s not much more complicated than sniffing a specialized saline solution. “It’s cleaning my bioaerosol footprint, if you will,” he says.

With his company Sensory Cloud, Edwards has developed a $50 product that has two components: the Nimbus and FEND. The Nimbus is an aerosol squirter, capable of turning liquid into a cloud of vapor that you puff in front of your nose to inhale from the air. FEND is a solution that goes inside the squirter, composed of a mix of salts similar to seawater.

In a recent study on 10 subjects, Edwards demonstrated that inhaling the solution can reduce potentially infected aerosols—droplets that fly from your nose and mouth while speaking or sneezing—by up to 99% for six hours. That means that if you have COVID-19, you should be less contagious to others. Plus, Edwards believes it could help prevent the SARS-CoV-2 virus from moving from your upper respiratory system (your nose) down to your lungs, too.

While the Nimbus is a personal device, it can be shared between people (carefully) because it doesn’t go in your nose or body. Edwards imagines that an office, a restaurant, or a hospital could assign one person to pump it for each visitor who walks in, much like people do temperature checks or distribute hand sanitizer today. Each bottle costs $6 and can spray 250 doses, and while that cost is low, Edwards plans profits at scale, as he intends customers to buy subscription packages. “One hundred Nimbi could treat 50,000 people at a stadium,” he says.

How is this all possible?

As Edwards explains, your nose is “the body’s face mask.” Many viruses actually get caught inside your nose like a trap, thanks to mucus. From there, your entire respiratory tract is protected with airway lining fluid, a mix of mucus and fluid that protects the cells like a sticky raincoat. Cilia in those cells beat the liquid to clear it away and any infections stuck inside. But when you cough, tiny bits of that fluid, filled with viruses, can break away. They can fly out of your mouth to infect someone else. Or they can float deeper into your airway, infecting your lungs. Aerosols are a two-way street of infection, both out of your body and deeper therein.

In 2004, Edwards was researching how to protect people from anthrax, the quintessential airborne biological weapon. As part of that research, he looked at mucins, the protein building blocks inside mucus.

“It led to a paper . . . an observation that when you inhale simple saline—sodium chloride—there’s an effect that salt has on mucins and mucin-like proteins and . . . that leads to a calmness of surface in airways,” Edwards says. “It was a minor effect but an effect. For several years we dug into this.”

When you breathe in salt and water, the fluid in your trachea has a greater surface tension. So when you talk or cough, the equivalent of high winds blow across the liquid in your respiratory tract. The effect of saline is that tiny droplets are less likely to break away from the surface. The chemistry at work isn’t terribly complicated: Calcium chloride (a salt) has two positive charges. Mucus proteins are negatively charged. So the calcium in the liquid actually glues two mucus proteins together at the molecular level. (Four aerosol experts we reached out to in order to validate the product’s claims were unavailable for comment.)

Edwards was only able to develop the device so quickly in response to COVID-19 because he originally designed it for something else. It was a food product that Edwards had been working on for appetite control, and he had planned to release it this year. An earlier endeavor in inhalable food was called Le Whif, and it let you puff a few calories of chocolate powder instead of blowing your diet on a whole chocolate bar. This was followed up by Le Whaf, a device that used ultrasonic waves to vaporize cocktails. Le Whif is no longer in production; Le Whaf still makes international appearances at various events.

But as COVID-19 spread across the globe earlier this year, Edwards back-burnered his food products and turned his attention to public health. The Nimbus is calibrated to mist the saline solution in 10 micron droplets. As he explains, if it misted in 50 micron droplets, they’d all end up in your nose. If it misted in 2 micron droplets, they would go straight to your lungs like an inhaler. At 10 microns, the aerosol lands inside the sweet spot of your trachea and bronchi.

Edwards currently has thousands of Nimbuses already produced. And he has licensed the FEND saline solution from the pharmaceutical company Pulmatrix. He is currently beginning pilot studies with the Beth Israel Hospital in Boston, while enlisting schools and offices to take part, too.

Right now, you can purchase a Nimbus system for yourself with two bottles of FEND solution for $49 shipping this September, and Edwards says it can mitigate the spread of not just COVID-19, but any aerosol cold or flu, too.

Will the Nimbus prove effective in real-world testing? While the study showed promising results, it was small, and it didn’t replicate the conditions of millions of people worldwide battling a pandemic. Even if it does work as advertised, can people really be persuaded to inhale something, given the reluctance many of them have to wearing masks? I for one am much more likely to trust a Harvard professor than a dangerous crackpot suggesting we inject bleach.