Influence of UV Irradiation and Environmental Factors on the Size-Dependent Survivability of Bioaerosols
WEIXING HAO, Yang Wang, Yue-Wern Huang,
Missouri University of Science and Technology Abstract Number: 232
Working Group: Bioaerosols
AbstractIndoor environments are ideal spaces for airborne transmission due to the favorable relative humidity (RH) and temperature levels, as well as the absence of ultraviolet germicidal irradiation (UVGI) light. These factors will affect the survival of indoor bioaerosol transport in various ways and to varying degrees, further complicating our understanding of the risks associated with indoor bioaerosols. Additionally, aerosol size is an essential factor in determining the survivability of indoor bioaerosols because it impacts the deposition pattern in the human respiratory system and the evolution of bioaerosols in an indoor environment. However, the size-dependent load and survivability of microorganisms under UVGI have not been studied in detail.
Here, we investigated the influence of UV irradiation intensity, temperature, relative humidity on the load and size-dependent survivability of two viruses (MS2 and Phi6) and two bacteria species (
Escherichia coli and
Staphylococcus aureus) bioaerosols in a temperature (10 to 60
oC), relative humidity (20 to 90%) and UV intensity (10 to 40 μW/cm
2) controlled small-scale laboratory test chamber. The aerosols were collected with a BioSampler, Sioutas cascade impactor, filter cassette containing gelatin filter. The results indicated that UV irradiation intensity, temperature and humidity are all significant factors of survivability. The survivability is inversely correlated with the UV intensity with a killing effect of 99% at 40 μW/cm
2. We demonstrated that bioaerosol size is a critical parameter influencing the load and survivability of microorganisms. Our understanding of the environmental factors can lead to an improved control of indoor infectious disease transmission.