Can Air Purifiers Kill COVID-19?
The answer to this question is: "Always be cautious of claims that have no scientific research or studies to back them up".
People wear masks because they either believe something is better than nothing or they believe the general scientific conclusion that if everyone wears proper masks it can slow the spread. The reality is, not all masks are created equal nor are all air purifiers.
COVID-19 is a nanoparticle (.001 to .1 microns) with a diameter of range of approximately 60-140 nanometers. Check out our blog on microns. Hence, the COVID-19 Virus size is .06 to .14 microns. One of the major reasons you've heard so much about N95 masks is because they filter out at least 95% of .3 micron size particles. Many air purifiers with Medical Grade HEPA filters have technical specifications that indicate efficacy of 99.7% at .3 microns and 95% at .1 microns. However, ULPA filters boast 99.99% at .1 microns.
But, what about COVID-19 sizes at .06 microns? In general, you might think that very small particles can still get through .1 micron HEPA filters, but it's a bit more complicated than that. Very small particles bounce around and move in zigzag patterns known as Brownian motion. So, given this effect, even very small particles can be captured by HEPA filters.
STUDIES ON HEPA AND OTHER AIR PURIFICATION TECHNOLOGY
In fact, the Experimental Study of Nanoparticle Penetration Through Commercial Filter Media performed at the University of Minnesota showed that 99.9% of nanoparticles were captured by the high grade HEPA filter used in their testing, which demonstrates that Brownian motion and HEPA together can make a very effective air purification system. Further, air purifiers that combine HEPA with UV light disinfect the captured particles. As for the effectiveness of UV, the FDA states:
"UVC radiation has been shown to destroy the outer protein coating of the SARS-Coronavirus, which is a different virus from the current SARS-CoV-2 virus. The destruction ultimately leads to inactivation of the virus. UVC radiation may also be effective in inactivating the SARS-CoV-2 virus, which is the virus that causes the Coronavirus Disease 2019 (COVID-19)."
Finally, it is important to understand that there are other air purification technologies that don't use HEPA filters. Some of these filter-less devices are also highly effective at destroying nano-sized particles.
We invite you to shop our store and find an air purifier that suits your needs and that can be another effective tool used to fight COVID-19 in your own home. Not only do we carry air purifiers with high grade HEPA and UV but we also carry Ionic Wind devices that destroy particles down to .0146 microns, and Photocatalytic Oxidation technology developed and used by NASA.
So, can air purifiers kill Covid-19? Yes, but it depends on the technology used by the device and requires adequate testing in order to make that claim.
In the March, 2020 Guidance Document Enforcement Policy for Sterilizers, Disinfectant Devices, and Air Purifiers During the Corona Virus Disease 2019 (COVID-19) Public Health Emergency the FDA recommended the following evaluation for air purifiers:
1. Demonstration of a 4 log reduction (through a combination of capture or destruction) of claimed particulates. See (Texas A&M Study): Reducing Airborne Microbes in the Surgical Operating Theater and Other Clinical Settings (Cram et.al).
2. If intended for use against bacteria, effectiveness against representative gram positive and gram negative species. See (Texas A&M Study): Reducing Airborne Microbes in the Surgical Operating Theater and Other Clinical Settings (Cram et.al).
3. If intended for use related to SARS-CoV-2, effectiveness against a representative virus.
4. If the device generates ozone, the maximum acceptable level of ozone per 21 CFR 801.415.
5. If intended for use in areas that have a sterile field or controlled air flow, a risk assessment to address turbulent air flow and/or potential site contamination.