AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
A Rotating Drum System with Environmental Conditioning for Research on Bioaerosols
KELLY BRINKLEY, Benjamin Alvarez, Daniel Hahn, Elizabeth Corson, Michael Herman, Thomas Buckley, Michael House, Daniel Simon, Johns Hopkins University Applied Physics Laboratory
Abstract Number: 710 Working Group: Bioaerosols
Abstract Environmental factors such as light, ozone, temperature and humidity potentially affect the physical or chemical attributes of a bioaerosol as well as its viability. Study of these interactions and assessment of their impact over time is important to areas of public health and biodefense. To address this research need, JHU/APL has designed, built and tested a Rotating Drum System (RDS), which is an aerosol testbed with temperature and humidity conditioning, simulated solar illumination, and controlled ozone injection, where each condition may be studied independently or coupled to simulate realistic environments.
JHU/APL conducted a series of tests to validate the RDS performance and capabilities for future research studies. Aerosolized polystyrene latex spheres (PSL) of 2 and 8µm were used to demonstrate the suspension capability of the 208L, 0.76m diameter drum. After 8hrs, 56% of 2µm PSLs remained and after 4hrs, 0.7% of 8µm PSLs remained, which was a measurable concentration of 86.2PPL. For 4 representative US weather setpoints of Hot/Humid (28°C/85%RH), Hot/Dry (40°C,20%RH), Cold/Humid(0°C/85%RH), Cold/Dry(5°C/35%RH), the RDS maintained the conditions within 0.2°C and 0.2%RH of the respective setpoints. Irradiance generated from the 6.5kW Xenon arc lamp matched the overall shape of the ASTM G177 spectrum for UV and Visible wavebands of interest (300-600nm). At these bands, the integrated irradiance was within 5% of the standard spectrum. The beam collimation was within 1⁰ and the uniformity varied less than 10% radially from center to edge at the entrance plane to the drum. Finally, the controlled ozone injection, which is designed to maintain ozone setpoints from 50 to 300ppb, maintained a mean concentration of 102ppb during a 6-hour test with a 100ppb setpoint.