Evaluation of multiple fixed in-room air cleaners with ultraviolet germicidal irradiation, in high-occupancy areas of selected commercial indoor environments

Abstract

The use of ultraviolet germicidal irradiation (UVGI) to combat disease transmission has come into the international spotlight again because of the recent SARS-CoV-2 pandemic and ongoing outbreaks of MDROs (multidrug resistant organisms) in hospitals. Although the implementation of ultraviolet disinfection technology is widely employed in healthcare facilities and its effectiveness has been repeatedly demonstrated, the use of such technology in the commercial sector has been limited. Considering that most disease transmission occurs in commercial, public, and residential indoor environments as opposed to healthcare facilities, there is a need to understand whether ultraviolet (UV) disinfection technology can be effective for mitigating disease transmission in these environments. The results presented here demonstrate that the installation of fixed in-room UVGI air cleaners in commercial buildings, including restaurants and offices, can produce significant reductions in both airborne and surface borne bacterial contamination. Total airborne reductions after UV implementation at six separate commercial sites averaged 73% (p<0.0001) with a range of 71-88%. Total non-high touch surface reductions after implementation averaged 55% (p<0.0001) with a range of 28-88%. All reductions at the mitigated sites were statistically significant. The mean value of indoor airborne bacteria was 320 CFU/m 3 before intervention and 76 CFU/m 3 after. The mean value of indoor non-high touch surface borne bacteria was 131 CFU/plate before intervention and 47 CFU/plate after. All test locations and controls had their required pandemic cleaning procedures in place for pre-and post-sampling events. Outdoor levels of airborne bacteria were monitored and there was no significant correlation between the levels of airborne bacteria in the outside air as opposed to the indoor air. Rooms with fixed in-room UVGI air cleaners installed had significant CFU reductions on local surface contamination, which is a novel and important finding. Installation of fixed in-room UVGI air cleaners in commercial buildings will decontaminate the indoor environment and reduce hazardous exposure to human pathogens.

Reduction of airborne and surface-borne bacteria in a medical center burn intensive care unit using active, upper-room, germicidal ultraviolet (GUV) disinfection

“…These results corroborate earlier studies on the same or similar GUV air disinfection devices in which airborne bacteria levels were significantly reduced. 17,[21][22][23][24] Previous studies have demonstrated that GUV can be effective at reducing airborne concentrations for a wide variety of pathogens, including M. tuberculosis, Staphylococcus aureus, S. albus, E. coli, Streptococcus pneumoniae, Serratia marcescens, Pseudomonas aeruginosa, P. fluorescens, Proteus vulgaris, Moraxella catarrhalis, influenza A, SARS-CoV-2 coronavirus, and various other pathogens that cause upper-respiratory infections. [8][9][10]12,13,[23][24][25][26][27][28][29][30][31][32][33] The result that air disinfection is significantly associated with the reduction of surface contamination is an important finding and corroborates previous studies.…”

Investigations on the Efficacy of Ozone as an Environmental Sanitizer in Large Supermarkets

“…The dynamic change in microbial load in supermarkets or other commercial establishments has been reported [ 20 , 21 ], but to our knowledge, this is the first study that compare both bacterial and fungal contamination in supermarkets equipped with ozonation systems and supermarkets without.…”

“…In particular, Lee et al [ 20 ] reported the results after the installation of fixed in-room ultraviolet germicidal irradiation air cleaners in commercial buildings, including restaurants and offices, demonstrating the significant reductions in both airborne and surface-borne bacterial contamination, even if the same authors pointed out that occupancy levels of commercial establishments varied according to their location, representing a limitation of the study.…”

Wind of change: Better air for microbial environmental control

“…UV-C lamps are already in use in operating rooms to reduce air contamination [ 41 ]. Lee et al evaluated the effectiveness of fixed ultraviolet germicidal irradiation (UVGI) air purifiers in restaurants, offices and meeting rooms: it was found that this tool can reduce bactericidal contamination in the air by 73% (p <0.0001) [ 42 ]. The study by Guimera et al demonstrated that the in-chamber UVGI device reduces bacterial contamination by 62% [ 42 ].…”

“…Lee et al evaluated the effectiveness of fixed ultraviolet germicidal irradiation (UVGI) air purifiers in restaurants, offices and meeting rooms: it was found that this tool can reduce bactericidal contamination in the air by 73% (p <0.0001) [ 42 ]. The study by Guimera et al demonstrated that the in-chamber UVGI device reduces bacterial contamination by 62% [ 42 ]. This is in agreement with Ritter et al who conducted a study comparing rooms with UV lighting and no UV lighting during total joint arthroplasty (TJA) procedures for 19 years.…”