Proven real-time bioaerosol detection technology based on UV fluorescence and elastic scattering is applied for detecting 0.5 – 10 μm airborne particles of biological origin by Environics ENVI BioScout. Particle-laden air is continuously drawn to the device through a prefilter with the cut-off at 10 μm. The air flow is directed through a virtual impactor like concentrator to an optical measurement chamber, in which the concentrated air sample is excited with a CW laser diode at 405 nm. In the optical system, the fluorescence light emitted and the light scattered by the particles in the air flow is gathered and directed with mirrors and optical filters to photomultiplier tubes that record the scattering and fluorescence signals. This signal information is processed by the advanced alarm algorithm to issue alarms in the case potentially harmful biological particles are detected.
In addition to detection technology, ENVI BioScout employs easy and efficient filter sampling for collection of further bioaerosol sample at the time of a biological alarm. Bioaerosol are collected on dry membrane filters like PTFE filters suitable for variable environmental conditions or viability preserving gelating filters with high moisture content. The collected air samples can be retrieved with a short rinsing protocol and the solubilized samples can be used for biological identification e.g. with rapid immunoassays and PCR techniques.