Development of a personal bioaerosol sampler based on a conical cyclone with recirculating liquid film

This article describes the development of a novel, high-performance personal aerosol sampler intended to monitor occupational air pollution, specifically, microbial constituents. This prototype sampler has a horizontally positioned conical cyclone with recirculating liquid film and an ejection supply of adsorptive liquid into the inlet nozzle. Airborne pollutants were collected in the adsorptive liquid, thus improving the survivability of microbiological aerosol samples. Experimental modules of different dimensions were first evaluated. Based on the test results, a prototype sampler was fabricated and tested. Evaluation of the collection efficiency of the prototype unit indicated a higher than 90% collection efficiency for particles > 1.0 microm. The 50% cutoff diameter was between 0.70-0.75 microm. For assessment of the sampling process effect on the collected microorganisms, Bacillus thuringiensis was tested at a concentration of about 1.0 x 10(6) cells per cm(3). The viability in the prototype sampler decreased to 78% after 60 min of operation.