The impact of environmental aging processing on bioaerosol detection using circular intensity differential scattering (CIDS)

Circular intensity differential scattering (CIDS) has recently been used to discriminate biological from non-biological particles based on direct detection of nucleic acids in single individual particles. Most sensors that discriminate biological from non-biological particles are based on laserinduced fluorescence (LIF). Although LIF can be used to sample and analyze aerosol particles continuously, but its detection signatures are altered by different atmospheric conditions, complicating the interpretation of LIF sensor data. Since CIDS signals are based on the chirality of nucleic acids, environmental damage to nucleic acid is not likely to impact the CIDS return in the same way that it impacts the LIF signal. To test this hypothesis, MS2 aerosol particles were generated and exposed to both simulated sunlight and ozone in a Biological Aerosol Reaction Chamber (Bio-ARC). These rapidly aged particles were measured by a Wideband Integrated Bioaerosol Sensor (WIBS-4a), which measures aerosol fluorescence excited at 280 and 370 nm, and a novel aerosol measurement system that relies on CIDS. The impact of this simulated aging on both LIF and the CIDS returns will be evaluated. Since LIF and CIDS returns were impacted differently by environmental aging processes, the results showed a greater stability of CIDS measurements and highlighted its potential application in rapid detection and characterization of bioaerosols.