More than Just Air Purification

The Science Behind Eradication of Coronavirus and Other Pathogens

By NoviSphere™ Staff

In early 2020, our NoviSphere PE 254 pathogen-eradication system was already well into development, with an intended spring launch. Then, the deadly COVID-19 pandemic hit, and we knew that bringing the product to market would not be truly viable unless we ensured that the technology could kill coronaviruses. To this end, we engaged with experts in pathogens and aerosol science from the University of Minnesota to test the unit’s efficacy against a COVID-19 surrogate strain.

The university team’s findings were written up in an article that is currently available for review and feedback by readers of Environmental Science & Technology. Published by the American Chemical Society, Environmental Science & Technology is a highly selective journal and only a small fraction of the papers submitted to it successfully complete the peer-review process and are published. The article is slated for publication in an upcoming issue of that journal, highlighting both the importance of the results and the quality of the experiments performed.

Summarized in this post are highlights from the article – most notably, the researchers finding that the prototype NoviSphere unit was 99.99% effective in eradicating a wide range of pathogens, including coronavirus.

The introduction explains that SARS-CoV-2, the strain of coronavirus that causes COVID-19, can be spread via both direct aerosol (inhalation of airborne particles) and indirect aerosol (touching of infected surfaces) routes. As coronaviruses can remain present in an aerosol at room temperatures for some length of time, the need exists for technologies that can directly mitigate an infectious virus surviving in an aerosol. Ultraviolet germicidal irradiation at wavelengths of 100-280nm (UV-C light) has been known for more than 80 years as being effective at preventing transmission of airborne diseases, and thus holds promise for eliminating coronaviruses.

Subsequent testing of a prototype ducted UV-C system built by NoviSphere was conducted to confirm this capability. The University of Minnesota researchers used porcine respiratory coronavirus (PRCV, an alpha coronavirus) as a surrogate for SARS-CoV-2, together with a monochromatic 254nm UV-C light and a custom wind tunnel constructed specifically for this purpose. As the authors note, “…[T]here is clearly increased importance in establishing proven technologies for airborne coronavirus removal and inactivation applicable to large volumes of air, or at flow rates higher than traditional bench scale experiments.”

The article next describes in-depth the research methodology, including all materials, measurement and data analysis steps pursued. Following this section, the authors describe their results. Of particular interest is the sub-section on virus removal and inactivation. They explain that PRCV was chosen as a coronavirus surrogate for this research effort since it requires biosafety level (BSL) class II facilities for experimentation (the University of Minnesota Veterinary Isolation Facility in St. Paul is BSL class II certified), and the researchers were able to propagate the PRCV to the high volumes needed to conduct the experiments.

The full study provides details regarding the system’s performance in efficiently inactivating aerosol coronaviruses. The bottom line is that researchers found that zero viable virus particulate survived passing through the prototype NoviSphere PE-254 unit, thus validating the unit as 99.99% effective.

Interested in learning more? Register to download the full study here.