Integrated multi-purpose bioaerosol testbed for characterization of UV-LIF-based particle counting and sizing instruments and environmental background monitoring

Abstract

Test and evaluation (T&E) of bioaerosol detectors presents unique measurement challenges, especially when evaluating systems designed to operate in complex battlefield environments. Equipment used to referee such T&E operations must be able to characterize the operating environment, including complex bioaerosol backgrounds, and the bioaerosol challenge presented to the detector. Test aerosols often represent only a fraction of the total atmospheric aerosol load. Therefore, selection of effective measurement equipment involves first developing an understanding of the natural background in environments where bioaerosol detectors may be used. It is also helpful to have a single platform for common sampling, so that multiple technologies may be evaluated under the same conditions for effective comparison. Such a platform was designed, characterized, and deployed under a cooperative development effort between the United States and Norway executed by the US Army Chemical Biological Center (CBC) and the Norwegian Defence Research Establishment (FFI). The testbed design is presented along with results from aerosol tests performed to document the sampling efficiency of the common inlet and isokinetic sampling manifold across a wide particle size range. The current testbed implementation hosts one Aerodynamic Particle Sizer (APS) and two ultraviolet light induced fluorescence (UVLIF) based bioaerosol particle counting and sizing instruments: the Ultra-Violet Aerodynamic Particle Sizer (UV-APS), and the Wideband Integrated Bioaerosol Sensor (WIBS). A comparative performance analysis of the two UV-LIF systems will be presented, as well as results describing the natural bioaerosol background at locations in both the US and Norway, including particle concentration, size distribution and fluorescence trends.