Greater than 3-Log Reduction in Viable Coronavirus Aerosol Concentration in Ducted Ultraviolet-C (UV-C) Systems

Yuechen Qiao, My Yang, Ian A. Marabella, Devin A.J. McGee, Hamada A Aboubakr, Sagar Goyal, Chris Hogan, Bernard A Olson, Montse Torremorell

Research output: Contribution to journalArticlepeer-review


Control technologies to inactivate airborne viruses effectively are needed during the ongoing SARS-CoV-2 pandemic, and to guard against airborne transmitted diseases. We demonstrate that sealed UV-C flow reactors operating with fluences near 253 ± 1 nm of 13.9-49.6 mJ cm-2 efficiently inactivate coronaviruses in an aerosol. For measurements, porcine respiratory coronavirus (PRCV) was nebulized in a custom-built, 3.86 m wind tunnel housed in a biosafety level class II facility. The single pass log10 reduction of active coronavirus was in excess of 2.2 at a flow rate of 2439 L min-1 (13.9 mJ cm-2) and in excess of 3.7 (99.98% removal efficiency) at 684 L min-1 (49.6 mJ cm-2). Because virus titers resulting from sampling downstream of the UV-C reactor were below the limit of detection, the true log reduction is likely even higher than measured. Comparison of virus titration results to reverse transcriptase quantitative PCR and measurement of fluorescein concentrations (doped into the nebulized aerosol) reveals that the reduction in viable PRCV is primarily due to UV-C based inactivation, as opposed to physical collection of virus. The results confirm that UV-C flow reactors can efficiently inactivate coronaviruses through incorporation into HVAC ducts or recirculating air purifiers.

Original languageEnglish (US)
JournalEnvironmental Science and Technology
StateAccepted/In press - 2020

Bibliographical note

Funding Information:
This work was supported by Novisphere, LLC. We acknowledge the staff of the University of Minnesota Veterinary Isolation Facility, as well as University of Minnesota College of Science and Engineering Machine shop for construction of the mixing plates used in the wind tunnel.

PubMed: MeSH publication types

  • Journal Article

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