Evaluation of an air cleaning device equipped with filtration and UV: comparison of removal efficiency on particulate matter and viable airborne bacteria in the inlet and treated air

Authors: LI, PEIYANG - Iowa State University; Koziel, Jacek; MACEDO, NUBIA - Iowa State University; ZIMMERMAN, JEFFREY - Iowa State University; WRZESINSKI, DANIELLE - Iowa State University; SOBOTKA, ERIN - Iowa State University; BALDERAS, MATEO - Iowa State University; WALZ, WILLIAM - Iowa State University; PARIS, REID VINCENT - Iowa State University; LEE, MYEONGSEONG - Texas A&M University; LIU, DONGJIE - Iowa State University; YEDILBAYEV, BAUYRZHAN - Al-Farabi Kazakh National University; RAMIREZ, BRETT - Iowa State University; JENKS, WILLIAM - Iowa State University

Submitted to: International Journal of Environmental Research and Public Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2022
Publication Date: 12/2/2022
Citation: Li, P., Koziel, J.A., Macedo, N., Zimmerman, J.J., Wrzesinski, D., Sobotka, E., Balderas, M., Walz, W.B., Paris, R., Lee, M., Liu, D., Yedilbayev, B., Ramirez, B.C., Jenks, W.S. 2022. Evaluation of an air cleaning device equipped with filtration and UV: comparison of removal efficiency on particulate matter and viable airborne bacteria in the inlet and treated air. International Journal of Environmental Research and Public Health. 19(23). Article 16135. https://doi.org/10.3390/ijerph192316135.
DOI: https://doi.org/10.3390/ijerph192316135

Interpretive Summary: Indoor air quality is crucial for human lives in residential and occupational settings, including livestock production and food supply chain. Since the COVID-19 outbreak, improving air quality has become vital for the public as the SARS-CoV-2 virus and other infectious diseases transmit via inhalable aerosols. In this research, a team of engineers and scientists from ARS, Iowa State University, Texas A&M University, and Al-Farabi Kazakh National University upgraded an air filtering prototype designed for large factory floors and public spaces with germicidal ultraviolet light (UV-C). The upgraded prototype was tested in challenging indoor environments with high loads of airborne pathogens and dust. The air cleaning prototype consistently inactivated nearly 100% of airborne pathogens and removed up to 97% dust. The combined filtration and UV-C treatment provided additional, ‘double-barrier’ assurance for purifying air and lowering the risk of spreading of infectious diseases that are relevant to both human and animal health. Many stakeholder groups that operate in large spaces with numerous employees and/or the public are interested in these results as a means of decreasing airborne disease transmission.

Technical Abstract: Since the COVID-19 pandemic, improving indoor air quality (IAQ) has become vital for the public as COVID-19 and other infectious diseases can transmit via inhalable aerosols. Air cleaning devices with filtration and targeted pollutant treatment capabilities can help improve IAQ. However, only a few filtration/UV devices have been formally tested for their effectiveness, and little data is publicly available and UV doses comparable. In this research, we upgraded a particulate matter (PM) air filtration prototype by adding UV-C (germicidal) light. We developed realistic UV dose metrics for fast-moving air and selected performance scenarios to quantify the mitigation effect on viable airborne bacteria and PM. The targeted PM included total suspended particulate (TSP) and a coarse-to-fine range sized at PM10, PM4, PM2.5, and PM1. The PM and viable airborne bacteria concentrations were compared between the inlet and outlet of the prototype at 0.5 and 1.0 m3/s (low and high) air flow modes. The upgraded prototype inactivated nearly 100% of viable airborne bacteria and removed up to 97% of TSP, 91% of PM10, 87% of PM4, 87% of PM2.5, and 88% of PM1. The performance in the low flow rate mode was generally better than in the high flow rate mode. The combination of filtration and UV-C treatment provided ‘double-barrier’ assurance for air purification and lowered the risk of spreading infectious micro-organisms.