Why smaller air purifiers could be a 'reasonable option' in coronavirus fight

A Moorhead day care operator says she's thrilled with the two units she runs in her home to try to keep everyone safe.

Erin Kay Ellingson and the 10 children she cares for in her Moorhead residence pose for a photo by the air purifying system she was awarded for her in-home day care. Special to The Forum

MOORHEAD — Erin Kay Ellingson, who operates an in-home day care for 10 children in Moorhead, thought this past winter about looking for an air purifying system to make her residence safer and possibly reduce the risk of the spread of the coronavirus.

She found a website and to her amazement was selected as a winner of two free $599 air purifier units that she has been "super pleased" with since they arrived at her home.

Although two quarantines hit her day care last November and in early February, she hasn't had any problems since she received the machines about three weeks ago.

She said not only has it perhaps helped with the coronavirus, but one child with an allergy to her dog has quit coughing and no longer has a drippy nose since the two purifiers were installed.

"I was hoping it would not only help with the coronavirus, but the flu, too," she added.


After testing the NuWave OxyPure purifier that Ellingson is using and two other similar units at the University of Minnesota mechanical engineering department, professor Chris Hogan and his team suggest that they can help.

Erin Ellingson air purifier.jpg
This is one of the two NuWave air purifiers that Erin Kay Ellingson has been operating in her home in an effort to try to keep the coronavirus and other illnesses at bay. Special to The Forum

The system that Ellingson has offers a 98.24% rate of collecting viruses from the air in a room of about 1,200 square feet, he said his research found.

The ideal would be a 99.9% rate, but he said filters do have very minor leaks.

"None are perfect," he said.

His "precise testing system," though, has been used on two other units with similar results.

In the tests, his team of researchers use a strain of coronavirus found in pigs and cows that gives them only minor symptoms but is similar in characteristics to the human virus.


The virus is fed through a wind tunnel system to the air purifier in a testing method he calls "hard to cheat."

For safety purposes, the tests are conducted in a bio-safe facility in the department.

Hogan said he wouldn't give a "yes or no" recommendation for day cares or public school classrooms to purchase air purifiers like this. What he did say is that it's a "reasonable option" in spaces where there can't be social distancing.

He said the purifiers can be especially helpful in older facilities — with many schools and homes fitting into that category — as well as during the winter months to almost eliminate virus particles in the air.

As spring and summer approach, his other main suggestion is to open windows as another way to increase ventilation rates and cut down on particles in the air.

Erin Ellingson.jpg
Erin Kay Ellingson and the 10 children she cares for in her Moorhead residence pose for a photo by the air purifying system she was awarded for her in-home day care. Special to The Forum

In agreement with Ellingson, he said opening windows or the air purifiers can be a boost for fighting the spread of allergies, colds or flu, too, although the outside air from open windows might not be good for allergies.


The three companies paid for the department's "impartial third party" testing operation, which he said he hoped people see as more believable than perhaps another company-sponsored lab results. Other company units will also be tested, although Hogan said they can't fulfill all of the requests.

The air purifiers, he said, wouldn't work in larger spaces, such as a school gymnasium.

As for the larger air ventilation systems on the market that government units and companies have been looking at for their buildings, he didn't offer an opinion because it wasn't part of the testing. He agreed with the premise expressed that they can be quite expensive.

Hogan said they began work a year ago on this project when the university was pretty much deserted, and they received special permission to start developing tests.

At the time, he never thought the aerosol science aspect of the department would receive as much attention as it has during the pandemic.

Ellingson said the units are "pretty quiet" and about the size of a dehumidifier.

"I think it would be a good investment," said the day care operator.

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