• Sustainable Energy Hawaii

Why Not Put Air Purifiers in classrooms?

Updated: Oct 14, 2020

Guest Column – Richard Ha

I’d like to make a case for air purifiers at our schools and other indoor sites.

Although most of us are trying to protect ourselves by wearing masks, staying six feet apart, and washing our hands frequently, Covid-19 continues to spread. It’s a new virus we don’t know enough about yet, and the experts’ advice keeps changing as we learn more.

We do know the virus seems to spread best indoors. Scientists are trying to convince the World Health Organization (WHO) to seriously consider that small, airborne particles of virus may suspend in the air and be pushed around by air currents. A July publication titled “It Is Time to Address Airborne Transmission of Covid-10” was published in the journal Clinical Infectious Diseases. The WHO responded that it is examining the evidence and will release updated recommendations.

It’s because of these airborne particles that air purifiers may be ideal.

Some schools and other buildings have air-conditioned rooms with HEPA air filters, which are 99 percent effective in filtering out particles 0.3 microns in size and larger. Many classrooms I've visited in Hilo don't have filtration at all, though, and many have poor airflow. It highlights the importance of managing air quality.

I was a farmer for 30 years and I have a lot of experience using respirators and filters.

At the start of the pandemic, the CDC told us masks were not necessary. Then they told us the reason we shouldn’t use personal protective equipment was because it was needed in hospitals. Then they said that everyone should be wearing masks. I worry we won’t learn the significance of airborne coronavirus transmission until later. Let’s address it now.

I'm not suggesting that air purifiers are a magic bullet that will solve the pandemic problem. But they might help.

I look at our teachers, many of whom are so worried about returning to the classroom. Experts say about 40 percent of people that transmit the virus have no symptoms. Say an asymptomatic student sits near an open classroom window, and the breeze carries the virus into the room.

An air purifier in the middle of that room would eliminate the coronavirus particles. Furthermore, if the air purifier ran all night, we’d know the air was clean the next morning. While we’d still need to do other cleanings, this would add another layer of security.

How do we get them in schools? Each Hawaii Island County Council member was authorized money for Covid-19 mitigation. Schools could call their County Council member and ask for help, to start.

We also see what is happening on Oahu at the prison, where Covid is spreading so fast they are talking about releasing some prisoners. What if there were an air purifier in each cell?

How about our Pacific Islander neighbors, who are over-represented in positive Covid cases? Many live in large family groups – what if they had air purifiers at home to decrease their risk?

I bought air purifiers with UV bulbs to deactivate the virus for everyone in my family to set up their bedroom and house as a safe space. It’s a little more expensive with the UV light, but that’s an additional layer of security. I wouldn’t have done that unless I felt it was important.

It’s been less than six months of this pandemic, and we’re still learning. We need to be extremely vigilant and open-minded. We cannot assume that what we discovered last week is the final answer. It’s all about risk assessment.

Air purifiers might be another important part of the answer.


Richard Ha, President, Sustainable Energy Hawaii,

and SEH board members Noel Morin, Peter Sternlicht, Lorie Smith, Jerry Chang, Noe Kalipi


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