1,544
Views
69
CrossRef citations to date
0
Altmetric
Original Articles

UV Air Cleaners and Upper-Room Air Ultraviolet Germicidal Irradiation for Controlling Airborne Bacteria and Fungal Spores

, , , &
Pages 536-546 | Published online: 23 Oct 2007
 

In-room air cleaners (ACs) and upper-room air ultraviolet germicidal irradiation (UVGI) are engineering control technologies that can help reduce the concentrations of airborne bacteria and fungal spores in the indoor environment. This study investigated six different types of ACs and quantified their ability to remove and/or inactivate airborne bacteria and fungal spores.Four of the air cleaners incorporatedUVlamp(s) into their flow path. In addition, the efficacy of combining ACs with upper-room air UVGI was investigated. With the ventilation system providing zero or six air changes per hour, the air cleaners were tested separately or with the upperroom air UVGI system in operation in an 87−m3 test room. Active bacteria cells and fungal spores were aerosolized into the room such that their numbers and physiologic state were comparable both with and without air cleaning and upperroom air UVGI. In addition, the disinfection performance of a UV-C lamp internal to one of the ACs was evaluated by estimating the percentage of airborne bacteria cells and fungal spores captured on the air filter medium surface that were inactivated with UV exposure. Average airborne microbial clean air delivery rates (CADRm) varied between 26–981 m3hr−1 depending on the AC, and between 1480–2370 m3hr−1, when using air cleaners in combination with upper-room air UVGI. Culturing, direct microscopy, and optical particle counting revealed similar CADRm. The ACs performed similarly when challenged with three different microorganisms. Testing two of the ACs showed that no additional air cleaning was provided with the operation of an internal UV-C lamp; the internal UV-C lamps, however, inactivated 75% of fungal spores and 97% of bacteria cells captured in the air filter medium within 60 min.

ACKNOWLEDGMENTS

The authors thank Millie P. Schafer, NIOSH, for her assistance, and for proposing the study of in-room air cleaning in combination with upper-room air UVGI. The authors also thank Leroy Mickelsen, NIOSH, for his assistance. The authors are grateful to Daniel Veronica, and the Joint Center for Energy Management for providing essential equipment and helping operating the test facility. We are grateful to Jennifer Jeffers for her help with laboratory work, and we acknowledge the help and support of Jay Julos.

This study was supported by funds provided by the Center for Disease Control and Prevention, the National Institute for Occupational Safety and Health, and the Shaklee Corporation.

Notes

ARetailer.

BIndependently measured at NIOSH facility (see Ref. 27).

A Number denotes the number of times that the experiment was repeated.

B EP, IUV, and EUV tested on high setting.

ARemoval rate determined by direct microscopy unless noted by a “C” or “OPC”, which indicates that culturing or optical particle counter was used.

BEP, IUV and EUV tested on high setting.

A The ventilation rate provided to the testroom was 0 air changes per hour.

BEP tested on high setting.

Log in via your institution

Log in to Taylor & Francis Online

PDF download + Online access

  • 48 hours access to article PDF & online version
  • Article PDF can be downloaded
  • Article PDF can be printed
USD 61.00 Add to cart

Issue Purchase

  • 30 days online access to complete issue
  • Article PDFs can be downloaded
  • Article PDFs can be printed
USD 148.00 Add to cart

* Local tax will be added as applicable

Related Research

People also read lists articles that other readers of this article have read.

Recommended articles lists articles that we recommend and is powered by our AI driven recommendation engine.

Cited by lists all citing articles based on Crossref citations.
Articles with the Crossref icon will open in a new tab.