Abstract View
Development and Characterization of an Environmental Rotating Aerosol Chamber for Long-term Bioaerosol Suspension
Esther Monroe, Nishit Shetty, Benjamin Sumlin, Joshin Kumar, GANESH CHELLUBOYINA, Rajan K. Chakrabarty, Washington University in St. Louis
Abstract Number: 446
Working Group: Bioaerosols
Abstract
In traditional chamber studies, aerosols are subject to gravitational settling and other wall losses which must be considered when studying the temporal evolution of the size distribution. To mitigate such losses, an Environmental Rotating Aerosol Chamber (ERAC) was conceived for bioaerosol applications where it is necessary to prolong the suspension of particles, especially in the sub-micron size range. Our ERAC is comprised of a 37.9-L cylindrical vessel which rotates about its axis, and the resulting centrifugal force counteracts the rate of gravitational settling. The ERAC is also equipped to control environmental factors such as temperature and relative humidity and is capable of disinfection by an internal 254 nm UV-C lamp. These parameters are monitored by integrated sensors, and the data acquisition is done via a microcontroller which interfaces to an external computer.
The suspension efficiency of the ERAC was evaluated using aerosolized 600 nm and 1 µm polystyrene latex beads. Measurements using an Aerodynamic Aerosol Classifier (Cambustion Inc.) coupled with a TSI condensation particle counter showed that at size-dependent optimal rotation rates, the ERAC can suspend sub-micron particles for over 24 hours, and that the steady-state rate of aerosol loss approaches the theoretical prediction values of the Gruel model. Following the chamber characterization, ERAC was used to investigate the effects of environmental conditions on inactivated virus particles over a 7-day period. In this talk, we will present experimental characterizations of the decay constants of the aerosol number concentration as a function of relative humidity, temperature, and particle aerodynamic diameter.