Until recently, there had been no or very little independent testing on the viability of bipolar ionization as an effective tool against the COVID-19 virus. Companies were drawing a conclusion based upon the technology’s ability to “deactivate” viruses of similar structure.
Based upon the available information, we have regarded this technology as promising, but not proven. In comparison, UVC has a calculatable efficiency at deactivating viruses based on the lighting intensity and exposure time. Historically, this has been our recommendation as a proven means of reducing environmental virus viability.
However, independent laboratories have been able to confirm that in their test environment, 99.9% of the virus was deactivated after 60 minutes, 99.4% at 45 minutes, and 82.3% at 30 minutes, based on a specific technology.
While UVC can be selected to kill 99.997% of viruses in a single pass, it only kills viruses in the air when it passes past the light. This is also why upper room UVC is so effective versus air-system installations, as it increases the typical room air change rate from a paltry 2-4 air changes per hour, up to a possible 50 or higher. Unfortunately, first cost, architectural limitations including low ceiling heights, and safety preclude the use of these devices in many spaces.
The benefit of properly applied bipolar ionization is that it continues to have efficacy within the space itself. If an HVAC system has an air change rate of 4, meaning air is replaced every 15 minutes, the UVC may have more initial effectiveness at the coil, but does not continue to work in the occupied space, and given that the air is only changed out of a typical office or classroom every 15-30 minutes, it may lack the effectiveness needed to mitigate spread of the virus in densely occupied spaces.
Bipolar ionization is typically less expensive than UVC to install, has a reasonable lead time for most applications, and has less ongoing maintenance. We will continue to provide information regarding this technology in future installments of Barton Insight. In the meantime, if you have any general and/or specific questions regarding bipolar ionization technologies as they are not all created equal, please contact Stephen Oskin, PE, LEED AP at 814-237-2180 or firstname.lastname@example.org.