AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Evaluation of the WIBS-4A for Biodefense-Related Applications
ELIZABETH CORSON, Jonathan Eshbaugh, David Drewry, Johns Hopkins University Applied Physics Laboratory
Abstract Number: 615 Working Group: Homeland Security
Abstract The Ultraviolet Aerodynamic Particle Sizer (UVAPS, TSI Inc.) has been utilized by the bioaerosol defense community for many years. The UVAPS measures single particle aerodynamic size, concentration, and fluorescence at 355 nm, parameters which are especially useful for the study of bioaerosols. In recent years, alternative bioaerosol measurement instruments have become available, including the Wideband Integrated Bioaerosol Sensor (WIBS-4A, Droplet Measurement Technologies Inc.), which has been used extensively for environmental research. The WIBS-4A provides measurements of particle size, particle aspect ratio, and fluorescence at two excitation wavelengths, 280 nm and 370 nm. The additional fluorescence measurement could aid in better discrimination of biological and non-biological particles. To better understand the utility of the WIBS-4A, various substances of interest, including Bacillus thuringiensis spores, vegetative bacteria, fluorophores, and environmental background, were aerosolized in the laboratory and measured with both the UVAPS and the WIBS-4A. Additionally, measurements of a vegetative bacteria aerosol exposed to ozone, relative humidity, and UV light, conditions known to change the fluorescence signature, were made with both instruments. Particle size, concentration, and fluorescence measurements from both instruments were compared and contrasted to explore the benefits as well as the limitations of the WIBS-4A in the context of defense-oriented applications. Due to differences in system design between the UVAPS and the WIBS-4A, the data they produce need to be interpreted differently, and methods for data interpretation are explored. With additional data channels as well as a compact form factor, the WIBS-4A has the potential to offer valuable insight into bioaerosols of interest to the defense community.