ScholarWorks@숙명여자대학교

초록

Atmospheric bioaerosols cause disease transmission and climate change and have various ecological impacts. In particular, bacterial viability in bioaerosols significantly influences shifts in the ecological environment and the spread of infectious diseases. Although many studies have focused on environmental factors, such as temperature and humidity, to estimate airborne bacterial survival, the effects of particulate matter (PM) have rarely been elucidated. Here, we hypothesized that bacteria cannot survive when dried in air and that drying time is a crucial factor governing their lifespan. We investigated changes in bacterial viability in the residue formed during evaporation of droplets containing micro- and nano-sized particles and bacteria. First, the effect of particulate presence on the survival of bacteria was confirmed through aerosol generation. To build a mathematical model, bacterial viability data were obtained from larger-sized droplets containing various particle compositions. A water evaporation model was employed to determine the relationship between evaporation time and bacterial lifespan in porous structures formed by bacteria and particles. Particle size and bacterial concentration were varied to control the structural properties of the residue. We found that the relative size and concentration of bacteria to the particles are key factors influencing droplet evaporation and bacterial lifespan. When bacteria and particles were similar in size, bacterial survival rates were relatively high and appeared independent of bacterial concentration, compared to cases with different particle sizes. This study provides a reference for analyzing airborne bacterial viability in relation to physicochemical properties and for evaluating the impact of PM on bacterial disease transmission.

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