Objective:To investigate the short and long tenn efficacy of a commercial air ionizer in killing Dermatophagoides pteronyssinus(D.pteronyssinus)and Dermalophagoides farinae(D.farinae)mites.Methods:The effect of a comm...Objective:To investigate the short and long tenn efficacy of a commercial air ionizer in killing Dermatophagoides pteronyssinus(D.pteronyssinus)and Dermalophagoides farinae(D.farinae)mites.Methods:The effect of a commercial ionizer on D.pteronyssinus and D.farinae was evaluated in the laboratory,using a specially designed test.Mortality was assessed after 6,16and 24 hours for direct exposure and after 24,36,48,60 and 72 hours for exposure in simulated mattress.New batches of mites were used for each exposure time.Results:LT_(50)for direct exposure of ionizer was 10 hours for D.pteronyssinus and 18 hours for D.farinae.The LT_(50)for exposure in simulated mattress was 132 hours or 5.5 days for D.pteronyssinus and 72 hours or 3days for D.farinae.LT_(95)for direct exposure of ionizer was 36 hours for D.pteronyssinus and D.farinae.Meanwhile,the LT_(95)for exposure in simulated mattress was 956 hours or 39.8 days for D.pteronyssinus and 403 hours or 16.8 days for D.farinae.Conclusions:This study demonstrates the increasing mite mortalities with increasing exposure time of a commercial ionizer and suggests that negative ions produced by an ionizer kill dust mites and can be used to reduce natural mile populations on exposed surfaces such as floors,clothes,curtains,etc.However,there is reduced efficacy on mites inside stuffed materials as in mattresses and furniture.展开更多
Infectious diseases(e.g.,coronavirus disease 2019)dramatically impact human life,economy and social development.Exploring the low-cost and energy-saving approaches is essential in removing infectious virus particles f...Infectious diseases(e.g.,coronavirus disease 2019)dramatically impact human life,economy and social development.Exploring the low-cost and energy-saving approaches is essential in removing infectious virus particles from indoors,such as in classrooms.The application of air purification devices,such as negative ion generators(ionizers),gains popularity because of the favorable removal capacity for particles and the low operation cost.However,small and portable ionizers have potential disadvantages in the removal efficiency owing to the limited horizontal diffusion of negative ions.This study aims to investigate the layout strategy(number and location)of ionizers based on the energy-efficient natural ventilation in the classroom to improve removal efficiency(negative ions to particles)and decrease infection risk.Three infected students were considered in the classroom.The simulations of negative ion and particle concentrations were performed and validated by the experiment.Results showed that as the number of ionizers was 4 and 5,the removal performance was largely improved by combining ionizer with natural ventilation.Compared with the scenario without an ionizer,the scenario with 5 ionizers largely increased the average removal efficiency from around 20%to 85%and decreased the average infection risk by 23%.The setup with 5 ionizers placed upstream of the classroom was determined as the optimal layout strategy,particularly when the location and number of the infected students were unknown.This work can provide a guideline for applying ionizers to public buildings when natural ventilation is used.展开更多
文摘Objective:To investigate the short and long tenn efficacy of a commercial air ionizer in killing Dermatophagoides pteronyssinus(D.pteronyssinus)and Dermalophagoides farinae(D.farinae)mites.Methods:The effect of a commercial ionizer on D.pteronyssinus and D.farinae was evaluated in the laboratory,using a specially designed test.Mortality was assessed after 6,16and 24 hours for direct exposure and after 24,36,48,60 and 72 hours for exposure in simulated mattress.New batches of mites were used for each exposure time.Results:LT_(50)for direct exposure of ionizer was 10 hours for D.pteronyssinus and 18 hours for D.farinae.The LT_(50)for exposure in simulated mattress was 132 hours or 5.5 days for D.pteronyssinus and 72 hours or 3days for D.farinae.LT_(95)for direct exposure of ionizer was 36 hours for D.pteronyssinus and D.farinae.Meanwhile,the LT_(95)for exposure in simulated mattress was 956 hours or 39.8 days for D.pteronyssinus and 403 hours or 16.8 days for D.farinae.Conclusions:This study demonstrates the increasing mite mortalities with increasing exposure time of a commercial ionizer and suggests that negative ions produced by an ionizer kill dust mites and can be used to reduce natural mile populations on exposed surfaces such as floors,clothes,curtains,etc.However,there is reduced efficacy on mites inside stuffed materials as in mattresses and furniture.
基金supports from the National Natural Science Funds for Distinguished Young Scholar(No.52225005)the National Natural Science Foundation of China(No.52178069)+2 种基金the Fundamental Research Funds for the Central Universities(No.4301002171)Concordia University-Canada,through the Concordia Research Chair-Energy&Environment,and the support received through the Engineering and Physical Sciences Research Council(EPSRC)–funded CO-TRACE(COvid-19 Transmission Risk Assessment Case studiesEducation Establishments,EP/W001411/1)the COVAIR(Is SARS-CoV-2 airborne and does it interact with particle pollutants?,EP/V052462/1)projects,and“Knowledge Transfer and Practical application of research on Indoor Air Quality(KTP-IAQ)”project that is funded by the University of Surrey’s Research England funding under the Global Challenge Research Fund(GCRF).
文摘Infectious diseases(e.g.,coronavirus disease 2019)dramatically impact human life,economy and social development.Exploring the low-cost and energy-saving approaches is essential in removing infectious virus particles from indoors,such as in classrooms.The application of air purification devices,such as negative ion generators(ionizers),gains popularity because of the favorable removal capacity for particles and the low operation cost.However,small and portable ionizers have potential disadvantages in the removal efficiency owing to the limited horizontal diffusion of negative ions.This study aims to investigate the layout strategy(number and location)of ionizers based on the energy-efficient natural ventilation in the classroom to improve removal efficiency(negative ions to particles)and decrease infection risk.Three infected students were considered in the classroom.The simulations of negative ion and particle concentrations were performed and validated by the experiment.Results showed that as the number of ionizers was 4 and 5,the removal performance was largely improved by combining ionizer with natural ventilation.Compared with the scenario without an ionizer,the scenario with 5 ionizers largely increased the average removal efficiency from around 20%to 85%and decreased the average infection risk by 23%.The setup with 5 ionizers placed upstream of the classroom was determined as the optimal layout strategy,particularly when the location and number of the infected students were unknown.This work can provide a guideline for applying ionizers to public buildings when natural ventilation is used.
