AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Fluorescence Characterization of Individual Bio-Aerosols and Ambient Air Measurements
VASANTHI SIVAPRAKASAM, John E. Tucker, Jay Eversole, Naval Research Laboratory
Abstract Number: 333 Working Group: Bioaerosols: Characterization and Environmental Impact
Abstract For more than a decade there has been a consistent effort at the US Naval Research Laboratory (NRL) to experimentally investigate the optical properties of aerosols particularly with regard to biological particle composition, for the purposes of developing bio-aerosol sensors. Throughout our history, we have pursued a guideline that the optimum environmental sensing capability will be achieved through on-the-fly, individual particle interrogation. We have previously developed a two-wavelength excitation (266 nm and 355 nm) based laser-induced fluorescence system to characterize individual micron-sized particles on-the-fly. This instrument has been extensively used to investigate the fluorescence properties of varying classes of biological agent simulants and potential ambient air interferents. Two-photon excited fluorescence from micron-sized aerosol particles was also explored using 270 nm, sub ps laser pulses for two common biological simulants. A version of the two-wavelength excitation system was developed along with an electro-static charging and collection capability in collaboration with Sarnoff Corp. (now SRI), which enables capture and collection of individual airborne particles in real time, based on their spectral emission signatures.
In April 2012, NRL inaugurated a new Laboratory for Autonomous Sensor Research, for developing and evaluating sensors under various environmental conditions. Included in this facility is a new Ambient Aerosol Test Facility (AATF) that draws in ambient air, enabling developmental sensors to sample local outdoor air continuously while remaining in a laboratory environment in order to achieve false positive testing over extended periods. The AATF includes an ability to mix various simulants and interferents in with ambient air for periodic true positive checks. Starting this summer, a long-term ambient data collection will commence with two sensor systems simultaneously: (1) two-wavelength fluorescence sensor and collector system mentioned above, and (2) a developmental single aerosol particle IR absorption spectral sensor. We will present a detailed description of the AATF system, as well as results of our latest outdoor data and sensor evaluations.