What Schools and Libraries Need to Know About Portable Air Cleaners
Have you been considering a portable air cleaner (PAC) to help control the spread of viruses and bacteria in your school or library, but you’re not sure if it’s what you need to keep everyone safe during the pandemic and beyond?
Researchers at the Harvard T.H. Chan School of Public Health recently released a report, “Portable Air Cleaners: Selection and Application Considerations for COVID-19 Risk Reduction,” which details the effectiveness of PACs in preventing the spread of illness in buildings such as schools and libraries.
We’ve summarized the findings for you below.
Portable Air Cleaners Help Defend Against the Spread of Airborne Viruses
According to the report, PACs, such as the Phoenix Guardian Air Scrubber, can play a key role in controlling the spread of airborne illnesses such as COVID-19. They do so by improving indoor air quality, especially in buildings where in-duct filtration and outside air ventilation is lacking, such as older buildings and libraries and classrooms in colder climates where windows stay closed for the winter.
PACs Should Be Combined with Other Safety Measures
Portable air cleaners are designed to reduce the concentration of contaminated airborne particles, which can contain and transmit viruses like COVID-19. Air cleaners do not prevent the transmission of large droplets from close contact or contagions through surface contact, so they must be combined with other safety measures, such as mask-wearing, hand-washing, social distancing, surface cleaning, and other guidelines recommended by the Centers for Disease Control and Prevention and local authorities.
Bigger Doesn’t Always Mean Better
In most rooms, the air throughout is nonuniform, with some areas having a heavier concentration of contaminant than others. Because of this nonuniformity, it is more effective to use several smaller PACs throughout your space than to use one bigger one if you have a large area to purify.
You may also want to consider the noise level of the fan and the effect that may have on the activities your space supports. You can operate two PACs at lower fan speeds (which means a lower clean air delivery rate for each) to reach maximum clean air effectiveness while keeping fan noise to a minimum.
Where You Place Your PAC in Your Room Matters
Because the air in your room is nonuniform, the placement of your portable air cleaner can play an important role in its effectiveness.
To be most effective, your PAC should be placed at breathing zone elevation rather than on the ground. This comes with some caveats, however.
- Be sure you’re not using your PAC as a fan. If the air is blowing across people, it can move virus-laden air to the breathing zones of other people.
- Make sure there aren’t any obstructions blocking the airflow of your PAC. Check the manufacturer’s recommendations for the distance of surrounding objects.
PACs Need to Have a HEPA Filter to Be Effective
Some air cleaning devices may use ozone, UVC, or ion-generators, none of which have been studied at the rate that fibrous media filters, or HEPA filters, have. These alternate technologies may also have negative effects on health, as they produce byproducts such as ozone. According to the Harvard study, only HEPA filters should be used to “provide supplementary protection against airborne COVID-19 transmission,” as they have the highest efficiency for removing airborne particles in a single pass.
An air cleaner with a HEPA filter can remove at least 99.97% of airborne particles with a size of .3 microns. Although the virus itself is as small as .1 microns, the Centers for Disease Control and Prevention and the Harvard School of Public Health recommend air cleaners for helping to reduce transmission of the virus, as they capture airborne respiratory particles that carry the virus.
Filters Need to Be Monitored
Over time, your PAC’s HEPA filter will collect dust and other particles, limiting airflow and reducing efficiency. This is a normal process that means the air filter is doing what it is designed to do; however, it’s important to replace the filter according to the manufacturer’s recommendations.
Now that you have a better understanding of portable air cleaners, read “What to Look for in a Portable Air Cleaner” to help you choose the best PAC for your needs.