10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Development of Wet-cyclone System for Highly Enriched, Continuous and Automated Bioaerosol Sampling in Real Time
YUSUNG CHO, Seung Chan Hong, Ki Joon Heo, Jae Hee Jung, Korea Institute of Science and Technology
Abstract Number: 629 Working Group: Bioaerosols
Abstract According to recent studies, most of the modern people have indoor activities of about 80-90% of the total activity time. As a result, there is a growing interest and demand for increasing social interest in indoor air quality and working environment conditions. Also, it has been reported that the inflow of fresh air from the outside is not performed smoothly due to the airtightness and improper air conditioning system operation, and physiological symptoms such as a headache, drowsiness, dizziness, and concentration decrease are reported. In particular, bioaerosols in fine dust are closely related to various airborne infections such as allergies and respiratory diseases, which can have adverse health effects on humans. Although sampling equipment has been developed for predicting and controlling the risk of fine dust and bioaerosols occurring in various environments, the equipment capable of real-time measurement and analysis has not yet been studied. In this study, we developed a wet-cyclone system capable of liquefying and collecting fine dust and bioaerosol in real time.
The wet-cyclone used in this study used design variables to have high efficiency and low separation particle size of conventional wet-cyclone. Also, the flow ratio (concentration ratio) between injected gas and liquid in the fabricated wet-cyclone was optimized (Orsini et al., 2008). Polystyrene latex spheres (PSL) were sprayed to test the particle collection performance of wet cyclone. Based on the obtained collection performance, the collection performance against bioaerosols was compared with the conventional BioSampler. In addition, for real-time particle collection performance test, the concentration of abruptly changing bioaerosols was compared with UV-APS (Ultraviolet Aerodynamic Particle Sizer), a real-time measurement instrument.
The operating conditions were determined according to the flow ratio between the gas and the liquid injected into the wet cyclone. From this, the particle collection efficiency according to each operating condition was measured. As a result, a collection performance of >99% particle collection efficiency and <1% particle loss was obtained based on 1 μm particles. Also, the wet-cyclone performed in this study showed higher biological collection efficiency than the conventional BioSampler in the evaluation of biological recovery efficiency (S. epidermidis). This is because as the gas and liquid are continuously injected into the wet-cyclone, a thin liquid film can be formed on the inner wall of the wet-cyclone, thereby relieving the physical impact when the particles are collected and stably collecting it. Furthermore, the real-time particle collection performance showed that it is possible to sample the concentration that changes every 1 minute after spraying the bacteria (S. epidermidis). This shows a similar pattern to UV-APS, which shows excellent performance in collecting and analyzing bioaerosols including fine dust particles in the air, which changes in real-time in various environments.
Our system could be useful for rapid and accurate airborne bioagent detection and monitoring system as an inexpensive, simple, portable, and continuous bioaerosol sampler.
This research was supported by the Ministry of Environment, Republic of Korea (2016000160008) and KIST Institutional Program.