10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Reduction of Fine Particle Exposure for Bedrooms in Home According to Operating Conditions of an Air Purifier
JUNHO JI, Gwang-Jae Lee, EcoPictures Co., Ltd.
Abstract Number: 643 Working Group: Indoor Aerosols
Abstract Human indoor activities generate airborne fine particles which contribute to the increase of indoor fine particle concentration at home. Ultrafine particles are emitted during some activities e.g. burning candle or incense, cooking, spray use, computer printing and household cleaning (Gehin et al., 2008). Recently, interest in fine particles has been increasing in Korea. This makes it difficult to ventilate in house when fine particle concentration in outdoor air is high. Portable air purifiers are widely used at home. However, a portable air purifier at home does not seem to be used properly. The purpose of this study is to clarify the relationship between the reduction of particulate exposure and the operating condition of the air purifier, that is, the air flow rate. This gives very useful information for the consumer using portable air purifiers. At the same time, carbon dioxide was measured to propose a ventilation cycle in the family bedroom. We expect to reduce the public’s anxiety against fine particles by supplying the field quantitative data. This study was conducted on the bedrooms of a small new apartment. The volume of each bedroom was 18.8, 22.8 and 24.84m3, respectively, and the test was conducted in an empty rooms. Area coverage of test air purifier was 29 square meter. An optical particle counter (OPC, portable aerosol spectrometer, model 1.109, Grimm, Germany) was used to monitor particle size distribution within the range 0.25–32 𝜇m. An indoor air quality (IAQ) monitor (NDIR CO2 Detector, model IQ-610xtra, GrayWolf Sensing Solutions, USA) was used to measure the CO2 concentration in the range from 0 to 10,000 ppm. First, we measured the characteristics of natural decay of PM10, PM2.5, and PM1. The initial particle size distribution affected to the reduction of particle concentrations. The larger the particle, the greater the concentration decrease due to gravity. Continuous operation of an air purifier reduces indoor fine particles. Over time, relatively large particles were removed quickly and concentrations of PM10, PM2.5 and PM1.0 were similar. The results show that as the operation air flow rate of the air purifier decreases, the Clean Air Delivery Rate (CADR), which represents the performance of the air purifier, is lowered. Compared with the maximum airflow condition of the air purifier, CADR in the low air flow rate was reduced by about one third. Under the maximum air flow rate, the amount of fine particle exposure decreased to 10% when compared with the initial fine particle concentration and to 40% at the low air flow rate condition. When there was one person in a 24.84 cubic meter room, the carbon dioxide concentration increased to 1290 ppm for 30 minutes. The amount of fine particle exposure decreased to 20% and 60%, respectively for the operation conditions of maximum and low air flow rates. However, when there were two people in a room, the concentration of carbon dioxide in the room rose to 1250ppm for 30 minutes and 1970 ppm for an hour. In future research, we will propose the operating time of the air purifier considering the ventilation cycle which can effectively reduce the fine particle exposure in the indoor bedroom and the living room.
References Gehin, E., Ramalho, O, & Kirchner, S. (2008) Atmospheric Environment, 42, 8341-8352.
Acknowledgement This research was supported by the National Strategic Project-Fine particle of the National Research Foundation of Korea(NRF) funded by the Ministry of Science and ICT(MSIT), the Ministry of Environment(ME), and the Ministry of Health and Welfare(MOHW). (2017M3D8A1091924)