Development of a multipoint aerosol sampler using critical flow control devices

To study the aerosol spatial distribution and behavior in a room, it is critical to measure aerosol concentrations across an airspace at multiple points simultaneously. There is a lack of a technique or instrument to measure multipoint aerosol spatial distribution accurately. A multipoint sampler has been developed using critical venturi that can control constant flow at a very low pressure drop of 10 kPa. This multipoint sampler was tested and evaluated in a full-scale ventilated room with particles supplied uniformly from the floor. Commercially available fine test dust was inducted into the room through a dust generation and a 25-point dust emission system on the floor. The experimental results showed that the multipoint sampler works well and aerosol spatial distributions can be measured. There was a significant spatial variability of dust within the ventilated air space. The highest concentration near the floor was four times higher than the lowest concentration near the ceiling. The experimental results also showed that the air ventilation system had a significant effect on the aerosol spatial distribution.