How Air Filtration Can Help Dissipate and Kill COVID-19

Modern hospitals are designed to minimize the risk of contagious diseases like tuberculosis from spreading.

UChicago Medicine’s hospital, for example, has both positive pressure rooms for surgical and oncology patients, in which the room’s higher pressure keeps out external air — and any potential contaminants it may carry — to help prevent infection, as well as negative pressure rooms designed for patients who need to be isolated.

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“Since the patient is the source of the contaminant what we want is the air to move into the room, mix with the patient’s air and then we can exhaust that air out of the building,” said Marco Capicchioni, UChicago Medicine’s vice president for facilities.

But UChicago Medicine didn’t initially have enough negative pressure rooms for the onslaught of COVID-19 patients it saw last year.

“We basically exceeded, at one point basically having more than 100 COVID patients, not all of the building areas were designed specifically for those isolation-type patients,” he said.

The hospital ended up converting rooms on two more floors into isolation spaces. In some cases, that was as easy as essentially flipping a switch by modifying a computer-controlled air system, Capicchioni said. But in other cases it required physical adjustments to the air supply and exhaust.

Crews also had to expand anterooms, “more commonly known as airlocks. Basically this is a room between the patient and the hallway, and this is a place where the staff can actually don and doff — you know, put on and take off — their PPE in a safe environment so that they’re not contaminating other areas.”

Most settings aren’t as carefully controlled as hospitals, but can still employ tactics and equipment to help break up potential airborne clusters of the novel coronavirus.

For 42 years, Glendale Heights-based Schubert Environmental Equipment has worked to remove toxins from industrial settings.

Engineer and owner John Schubert said the work has translated into attacking COVID-19. 

Industrial toxins and the coronavirus are both “low mass density” airborne particulate.

“Smoke – cigarette smoke, or welding smoke, or smoke from machine tools or foraging or steel mills – those are all in the neighborhood of 1 micron or less, plus or minus, and they float. And that’s exactly the same situation as the pathogen, and the virus. It’s a one foot per hour drop rate, it doesn’t take much to keep it always airborne. Until something grabs it,” he said. “The similarities are just very, very close between industry and this virus.”

Schubert’s company manufactures a “Patent Pending Portable High Energy Unit” device that “grabs” COVID-19 – grabs it, filters it, shakes it, batters it, shines ultraviolet rays on it and kills it.

(It’s two devices really, one air filtration system is smaller and more portable; the other is designed for spaces of up to 700 square feet.)

Schubert advises anyone contemplating buying a product to not be fooled by “efficiency” specifications and instead watch for how large a space a filtration system can cover – some, he said, are effective only for a room the size of a broom closet.

“What we want is effective use of an air cleaner,” he said.

That means that it’s capable of circulating the air every 10 minutes, or six air changes an hour; without that, air – and potentially the virus – builds up and concentrates.

He said some Chicago-area schools, hospitals and restaurants have purchased and used the devices.

But there are other ways to help break up floating COVID-19 clusters: as the Centers for Disease Control and Prevention advises, open a window.

“Run the furnace all the time, leave the blower on. That’s a strong recommendation. There’s a filter unit right there if you leave the blower on,” he said. “As the furnace demands heat or cool, it’ll come on and off, on and off, but you’ll always be moving air through these filters that you put in. Check them. 

“You want to get away from the open-weave filters that you can see your hand through,” he said.

While the temptation may be to go in the other direction, Schubert recommends that households shouldn’t go too far.

While “HEPA filter” has become a well-known term, that’s for industrial HVAC systems; Schubert said it would be too much for a household, heating, ventilation and air conditioning system.

“If you get too thick a filter, too efficient, it starts to fill and block air flow and then your heating and air condition unit cannot function, it’ll start to slow up the air, and then what you’ve done is, you’ve lost your air changes,” he said.

Schubert recommends trying a Merv 8 or 10 filter.

Follow Amanda Vinicky on Twitter: @AmandaVinicky

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