A Case Study of Upper-Room UVGI in Densely-Occupied Elementary Classrooms by Real-Time Fluorescent Bioaerosol Measurements.

Chunxiao Su,Josephine Lau,Fang Yu

doi:10.3390/ijerph14010051

Abstract

Recently, the requirement to continuously collect bioaerosol samples using shorter response times has called for the use of real-time detection. The decreased cost of this technology makes it available for a wider application than military use, and makes it accessible to pharmaceutical and academic research. In this case study, real-time bioaerosol monitors (RBMs) were applied in elementary school classrooms—a densely occupied environment—along with upper-room ultraviolet germicidal irradiation (UVGI) devices. The classrooms were separated into a UVGI group and a non-UVGI control group. Fluorescent bioaerosol counts (FBCs) were monitored on 20 visiting days over a four-month period. The classroom with upper-room UVGI showed significantly lower concentrations of fine size (<3 μm) and total FBCs than the control classroom during 13 of the 20 visiting days. The results of the study indicate that the upper-room UVGI could be effective in reducing FBCs in the school environment, and RBMs may be applicable in reflecting the transient conditions of the classrooms due to the dynamic activity levels of the students and teachers.

Highlights

Bioaerosols are biological aerosol particles suspended in air
This study indicates that real-time bioaerosol monitors (RBMs) detected fewer fluorescent bioaerosol counts (FBCs) in the ultraviolet germicidal irradiation (UVGI) classroom compared to the non-UVGI control room during the four months of measurement
This study evaluated the reduction of fluorescent bioaerosols counts by upper-room UVGI in classrooms with RBMs, and came to the following conclusions: 1

Summary

Introduction

Bioaerosols are biological aerosol particles suspended in air. This subset of aerosols contains fungi, viruses, bacteria, spores, and pollen. Bioaerosols in indoor environments—especially at high concentration—have been associated over the last several decades with a wide range of adverse health effects, such as inflammatory, respiratory, and allergic reactions [1,2,3,4,5]. Research has been carried out in schools and childcare environments, which are usually densely occupied. Upper-room ultraviolet germicidal irradiation (UVGI) with a wavelength range of 100–280 nm (UV-C) has been verified to efficiently disinfect airborne microbial organisms by inhibiting their ability to replicate [8,9,10,11,12,13]. Bacillus atrophaeus and Escherichia coli were nebulized

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Discussion

Conclusion