Charles J. Call

Design considerations and performance characteristics of AirSentinel: a new UV-LIF bio-aerosol threat detection trigger

AirSentinel® is a new low cost, compact ultraviolet-based light induced fluorescence (UV-LIF) bio-aerosol threat detection trigger. Earlier UV-LIF triggers, for example, FLAPS, BARTS, BAWS, Bioni, and BioLert, have used UV laser sources to induce fluorescence of biological aerosols. Two recent developments from the DARPA MTO SUVOS program, BAST and TAC-BIO, use UV LEDs for the same purpose, thereby broadening the term UV-LIF to mean laser or LED induced autofluorescence. All of these earlier triggers interrogate aerosols on a particle-by-particle basis on- the-fly. The major trade-off for these instruments is cost, size, and complexity versus counting efficiency (probability of detection) with the lower size end of the respirable range being most difficult to detect. AirSentinel® employs a different approach to UV-LIF detection: aerosol concentration by collection on a surface, surface interrogation, and surface rejuvenation prior to repeated concentration and interrogation cycles. Aerosol particle concentration via impaction on a surface addresses the issue of small particle counting efficiency since the fluorescence from the sum of the particles is the sum of the fluorescence signals from the collected particles, typically hundreds or thousands in number. Surface interrogation for a LIF signal is accomplished by illumination with a 280 nm and/or a 365 nm LED. As expected, test results show better relative detection performance using 280 nm excitation LEDs for bio-toxin simulants and somewhat better performance at 365 nm for standard Bacillus globigii spore targets. AirSentinel® beta technology is currently in long term testing in a number of public and other government buildings.

AirSentinel: a real-time bioaerosol monitor

A rationale for evaluating bioaerosol sensor technology for building protection applications is presented. Issues associated with bio-threat sensor systems for buildings include sensor performance metrics, standards and cost. The low-cost AirSentinel bioaerosol sensor is highlighted as an example of an approach that addresses the issue of affordability.

BioBadge: a personal dosimetry technology for assessment of exposures to biological agents

The BioBadge is a biological dosimeter product based on a personal collection device developed by MesoSystems Technology. Designed to be worn by individuals in potentially biologically hazardous environments, the BioBadge allows for real-time collection, concentration, and analysis of biological agents present in the air. It provides a measure of the wearer’s exposure, providing a means for determining the characteristic and extent of human health threat. In this article, the basic technology that comprises the BioBadge is discussed. Experimental results are presented which explore the performance of this technology. Also included is a simple example to illustrate the use of the wearable sampler.