In this study, a three-stage bioaerosol sampler with a sampling flow rate of 170 L/min was designed and fabricated for sampling the bioaerosols released during human breathing and coughing, and its performance was evaluated. The sampler was constructed using a cyclone separator with a cutoff size of 2.5 µm as a preseparator, a multi-nozzle virtual impactor with a cutoff size of 0.34 µm as an aerosol concentrator, and a BioSampler, which is a commercial product, for collecting bioaerosols in a collection fluid. The collection efficiency of the sampler was evaluated through simulations and experiments. Only particles with sizes of 0.1-4 µm were selectively collected in the collection fluid. Bacteriophage bioaerosols were sampled using the developed sampler and ACD-200 Bobcat sampler, which is a commercial product. The amounts of collected bacteriophages were compared using the polymerase chain reaction (PCR) technique. The sampling performance of the developed sampler was similar to that of the ACD-200 Bobcat sampler. Moreover, the developed sampler showed its ability to sample bioaerosols of a specific size-range and collect them directly in a collection fluid for the PCR analysis. Therefore, the developed sampler is expected to be useful for indoor environmental monitoring by effectively sampling the bioaerosols released indoors during human breathing and coughing.

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To accurately forecast the concentrations of fine and thoracic coarse particles [particulate matter (PM) 2.5 and 10, respectively], it is important to secure a large number of boundary conditions. For this purpose, particle concentrations need to be measured not only at predefined observatory sites but also in more regions. Various types of vehicles can be used for collecting ambient aerosol not only on the ground but also in the air, and thus it is necessary to use specially designed sampling probes that enable efficient sampling of particles in variable airstream velocity conditions. This study developed a double-shrouded probe as a representative sampling probe available within a range of stream velocity from 0 to 300 km h−1. An additional shroud was added to the outer face of a single-shrouded probe, and an annular tapered wing was added to a sampling tube. Numerical analyses and experiments were performed, and their results were compared. The double-shrouded probe was found to be appropriate for representative sampling of PM2.5 and PM10 at velocities of 300 km h−1 or less and 150 km h−1 or less, respectively, which are significantly extended compared to the range of the currently possible velocity for the single-shrouded probe. The double-shrouded probe onboard various types of air or land vehicles is expected to contribute to accurate measurements of PM concentration under the condition of a high-speed stream.

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