Fungal Spore Aerosolization at Different Positions of a Growing Colony Blown by Airflow

ABSTRACT 

The possible role of bioaerosols in the transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) causing the coronavirus disease 2019 (COVID-19) has recently been highlighted. A bioaerosol can be comprised of bacterial cells, fungal spores and viruses. Aerosolized fungal spores in indoor environments can cause adverse health effects. As a colony propagates from the center to the perimeter, the age of fungal spores and thus the adhesion force to the colony can be much different. The spore detachment may vary according to the growing position of the spores on a colony in relation to the airflow. This study investigated the aerosolization of fungal spores at different positions of a colony. A fungal colony was divided into a quantity of sub colonies according to the age distribution. Each sub colony was subjected to airflow in a wind tunnel to determine the released spores by two count methods. The results revealed that the initial spore density, the spore release rate, and the spore release proportion for the central sub colony were all significantly higher than that for the sub colony at the edge. The spore release rate for the central sub colony was approximately 2.6 times that at the edge. Spores growing at the center of the colony were aerosolized more easily than that growing at the outer edge. Growth age is a significant factor in the difference of spore aerosolization between sub colonies.