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Liu Z, Wang Y, Jiang C, He J, Rong R, Li S, Liang Z. Spatial distribution of bioaerosols and evaluation of four ventilation method on controlling their diffusion in a typical enhanced biosafety level 2 laboratory. JOURNAL OF HAZARDOUS MATERIALS 2024; 475:134942. [PMID: 38889462 DOI: 10.1016/j.jhazmat.2024.134942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Revised: 06/14/2024] [Accepted: 06/15/2024] [Indexed: 06/20/2024]
Abstract
Biosafety laboratories are critical in many fields. However, experimenters associated the infection risk from biological aerosols. In this study, by conducting experiments on the release and collection of bioaerosols within a typical BSL-2 + laboratory, the spatial distribution of bioaerosols was tracked. Numerical calculations were employed to obtain and visualize the airflow patterns and aerosol dispersion paths of four ventilation methods. The results indicated that equipment and tables led to uneven airflow distribution within the laboratory. The comparison results of the four evaluation indicators showed that the air age distribution of UU (Upward supply and upward return) mode and CD (Cross-supply and downward return) mode was superior, with air change efficiency values of 0.595 and 0.603, respectively. Additionally, the contaminant removal index of CD mode was 1.48, significantly higher than the other ventilation methods. The statistical results of the contaminant dispersion index also indicated that CD mode was most conducive to diluting aerosols in the spatial environment. The LD (lateral supply and downward return) mode may lead to airflow short-circuiting. The UD (upward supply and downward return) mode can provide balanced protection for laboratory. Overall, CD mode performed the best among the four ventilation methods, followed by UU mode.
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Affiliation(s)
- Zhijian Liu
- Department of Power Engineering, School of Energy Power and Mechanical Engineering, North China Electric Power University, Baoding 071003, Hebei, China.
| | - Yongxin Wang
- Department of Power Engineering, School of Energy Power and Mechanical Engineering, North China Electric Power University, Baoding 071003, Hebei, China
| | - Chuan Jiang
- Department of Power Engineering, School of Energy Power and Mechanical Engineering, North China Electric Power University, Baoding 071003, Hebei, China
| | - Junzhou He
- Department of Power Engineering, School of Energy Power and Mechanical Engineering, North China Electric Power University, Baoding 071003, Hebei, China
| | - Rui Rong
- Department of Power Engineering, School of Energy Power and Mechanical Engineering, North China Electric Power University, Baoding 071003, Hebei, China
| | - Shiyue Li
- The State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, China
| | - Zhenyu Liang
- The State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, China
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Liu Z, Li H, Chu J, Huang Z, Xiao X, Wang Y, He J. The impact of high background particle concentration on the spatiotemporal distribution of Serratia marcescens bioaerosol. JOURNAL OF HAZARDOUS MATERIALS 2023; 458:131863. [PMID: 37354722 DOI: 10.1016/j.jhazmat.2023.131863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 06/07/2023] [Accepted: 06/13/2023] [Indexed: 06/26/2023]
Abstract
Airborne transmission is a well-established mode of dissemination for infectious diseases, particularly in closed environments. However, previous research has often overlooked the potential impact of background particle concentration on bioaerosol characteristics. We compared the spatial and temporal distributions of bioaerosols under two levels of background particle concentration: heavily polluted (150-250 μg/m3) and excellent (0-35 μg/m3) in a typical ward. Serratia marcescens bioaerosol was adopted as a bioaerosol tracer, and the bioaerosol concentrations were quantified using six-stage Andersen cascade impactors. The results showed a significant reduction (over at least 62.9%) in bioaerosol concentration under heavily polluted levels compared to excellent levels at all sampling points. The temporal analysis also revealed that the decay rate of bioaerosols was higher (at least 0.654 min-1) under heavily polluted levels compared to excellent levels. These findings suggest that background particles can facilitate bioaerosol removal, contradicting the assumption made in previous research that background particle has no effect on bioaerosol characteristics. Furthermore, we observed differences in the size distribution of bioaerosols between the two levels of background particle concentration. The average bioaerosols size under heavily polluted levels was found to be higher than that under excellent levels, and the average particle size under heavily polluted levels gradually increased with time. In conclusion, these results highlight the importance of considering background particle concentration in future research on bioaerosol characteristics.
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Affiliation(s)
- Zhijian Liu
- School of Energy and Power Engineering, North China Electric Power University, Baoding 071003, China
| | - Haochuan Li
- School of Energy and Power Engineering, North China Electric Power University, Baoding 071003, China
| | - Jiaqi Chu
- School of Energy and Power Engineering, North China Electric Power University, Baoding 071003, China
| | - Zhenzhe Huang
- School of Energy and Power Engineering, North China Electric Power University, Baoding 071003, China
| | - Xia Xiao
- School of Energy and Power Engineering, North China Electric Power University, Baoding 071003, China
| | - Yongxin Wang
- School of Energy and Power Engineering, North China Electric Power University, Baoding 071003, China
| | - Junzhou He
- School of Energy and Power Engineering, North China Electric Power University, Baoding 071003, China.
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Wu D, Chen J, Fu X, Li Z, Tan F, Lin H. Study on the migration characteristics of bioaerosols and optimization of ventilation patterns in a negative pressure isolation ward considering different patient postures. PLoS One 2023; 18:e0290288. [PMID: 37590299 PMCID: PMC10434850 DOI: 10.1371/journal.pone.0290288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 08/06/2023] [Indexed: 08/19/2023] Open
Abstract
Due to the serious global harm caused by the outbreak of various viral infectious diseases, how to improve indoor air quality and contain the spread of infectious bioaerosols has become a popular research subject. Negative pressure isolation ward is a key place to prevent the spread of aerosol particles. However, there is still limited knowledge available regarding airflow patterns and bioaerosol diffusion behavior in the ward, which is not conducive to reducing the risk of cross-infection between health care workers (HCWs) and patients. In addition, ventilation layout and patient posture have important effects on aerosol distribution. In this study, the spatial and temporal characteristics as well as dispersion patterns of bioaerosols under different ventilation patterns in the ward were investigated using the computational fluid dynamics (CFD) technique. It is concluded that changes in the location of droplet release source due to different body positions of the patient have a significant effect on the bioaerosol distribution. After optimizing the layout arrangements of exhaust air, the aerosol concentration in the ward with the patient in both supine and sitting positions is significantly reduced with particle removal efficiencies exceeding 95%, that is, the ventilation performance is improved. Meanwhile, the proportion of aerosol deposition on all surfaces of the ward is decreased, especially the deposition on both the patient's body and the bed is less than 1%, implying that the risk of HCWs being infected through direct contact is reduced.
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Affiliation(s)
- Dieen Wu
- Guangzhou Panyu Central Hospital, Guangzhou, China
| | - Jianji Chen
- Guangzhou Panyu Central Hospital, Guangzhou, China
| | - Xihua Fu
- Guangzhou Panyu Central Hospital, Guangzhou, China
| | - Zongkun Li
- School of Electric Power, South China University of Technology, Guangzhou, China
- Guangdong Province Key Laboratory of Efficient and Clean Energy Utilization, Guangzhou, China
| | - Futai Tan
- Guangzhou Huijin Energy Efficiency Technology Co. Ltd, Guangzhou, China
| | - Hai Lin
- Guangzhou Huijin Energy Efficiency Technology Co. Ltd, Guangzhou, China
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Liu Z, Zhang P, Liu H, He J, Li Y, Yao G, Liu J, Lv M, Yang W. Estimating the restraint of SARS-CoV-2 spread using a conventional medical air-cleaning device: Based on an experiment in a typical dental clinical setting. Int J Hyg Environ Health 2023; 248:114120. [PMID: 36709744 PMCID: PMC9883001 DOI: 10.1016/j.ijheh.2023.114120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 12/14/2022] [Accepted: 01/24/2023] [Indexed: 01/28/2023]
Abstract
OBJECTIVES Droplets or aerosols loaded with SARS-CoV-2 can be released during breathing, coughing, or sneezing from COVID-19-infected persons. To investigate whether the most commonly applied air-cleaning device in dental clinics, the oral spray suction machine (OSSM), can provide protection to healthcare providers working in clinics against exposure to bioaerosols during dental treatment. METHOD In this study, we measured and characterized the temporal and spatial variations in bioaerosol concentration and deposition with and without the use of the OSSM using an experimental design in a dental clinic setting. Serratia marcescens (a bacterium) and ΦX174 phage (a virus) were used as tracers. The air sampling points were sampled using an Anderson six-stage sampler, and the surface-deposition sampling points were sampled using the natural sedimentation method. The Computational Fluid Dynamics method was adopted to simulate and visualize the effect of the OSSM on the concentration spatial distribution. RESULTS During dental treatment, the peak exposure concentration increased by up to 2-3 orders of magnitude (PFU/m3) for healthcare workers. Meanwhile, OSSM could lower the mean bioaerosol exposure concentration from 58.84 PFU/m3 to 4.10 PFU/m3 for a healthcare worker, thereby inhibiting droplet and airborne transmission. In terms of deposition, OSSM significantly reduced the bioaerosol surface concentration from 28.1 PFU/m3 to 2.5 PFU/m3 for a surface, effectively preventing fomite transmission. CONCLUSION The use of OSSM showed the potential to restraint the spread of bioaerosols in clinical settings. Our study demonstrates that OSSM use in dental clinics can reduce the exposure concentrations of bioaerosols for healthcare workers during dental treatment and is beneficial for minimizing the risk of infectious diseases such as COVID-19.
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Affiliation(s)
- Zhijian Liu
- Department of Power Engineering, North China Electric Power University, Baoding, Hebei, 071003, PR China.
| | - Peiwen Zhang
- Department of Power Engineering, North China Electric Power University, Baoding, Hebei, 071003, PR China
| | - Haiyang Liu
- Department of Power Engineering, North China Electric Power University, Baoding, Hebei, 071003, PR China
| | - Junzhou He
- Department of Power Engineering, North China Electric Power University, Baoding, Hebei, 071003, PR China
| | - Yabin Li
- The Fifth Medical Center of People's Liberation Army of China General Hospital, Beijing, 100039, China
| | - Guangpeng Yao
- Department of Power Engineering, North China Electric Power University, Baoding, Hebei, 071003, PR China
| | - Jia Liu
- The Fifth Medical Center of People's Liberation Army of China General Hospital, Beijing, 100039, China
| | - Meng Lv
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China
| | - Wenhui Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China.
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Singh AV, Katz A, Maharjan RS, Gadicherla AK, Richter MH, Heyda J, Del Pino P, Laux P, Luch A. Coronavirus-mimicking nanoparticles (CorNPs) in artificial saliva droplets and nanoaerosols: Influence of shape and environmental factors on particokinetics/particle aerodynamics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 860:160503. [PMID: 36442637 PMCID: PMC9691506 DOI: 10.1016/j.scitotenv.2022.160503] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 11/20/2022] [Accepted: 11/22/2022] [Indexed: 05/16/2023]
Abstract
Severe acute respiratory syndrome coronavirus 2, abbreviated as SARS-CoV-2, has been associated with the transmission of infectious COVID-19 disease through breathing and speech droplets emitted by infected carriers including asymptomatic cases. As part of SARS-CoV-2 global pandemic preparedness, we studied the transmission of aerosolized air mimicking the infected person releasing speech aerosol with droplets containing CorNPs using a vibrating mesh nebulizer as human patient simulator. Generally speech produces nanoaerosols with droplets of <5 μm in diameter that can travel distances longer than 1 m after release. It is assumed that speech aerosol droplets are a main element of the current Corona virus pandemic, unlike droplets larger than 5 m, which settle down within a 1 m radius. There are no systemic studies, which take into account speech-generated aerosol/droplet experimental validation and their aerodynamics/particle kinetics analysis. In this study, we cover these topics and explore role of residual water in aerosol droplet stability by exploring drying dynamics. Furthermore, a candle experiment was designed to determine whether air pollution might influence respiratory virus like nanoparticle transmission and air stability.
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Affiliation(s)
- Ajay Vikram Singh
- German Federal Institute for Risk Assessment (BfR), Department of Chemical and Product Safety, Max-Dohrn-Straße 8-10, 10589 Berlin, Germany.
| | - Aaron Katz
- German Federal Institute for Risk Assessment (BfR), Department of Chemical and Product Safety, Max-Dohrn-Straße 8-10, 10589 Berlin, Germany
| | - Romi Singh Maharjan
- German Federal Institute for Risk Assessment (BfR), Department of Chemical and Product Safety, Max-Dohrn-Straße 8-10, 10589 Berlin, Germany
| | - Ashish K Gadicherla
- German Federal Institute for Risk Assessment (BfR), Department of Biological Safety, Diedersdorfer Weg 1, 12277 Berlin, Germany
| | - Martin Heinrich Richter
- German Federal Institute for Risk Assessment (BfR), Department of Biological Safety, Diedersdorfer Weg 1, 12277 Berlin, Germany
| | - Jan Heyda
- University of Chemistry and Technology (UCT), 166 28 Prague 6, Czech Republic
| | - Pablo Del Pino
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Física de Partículas, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Peter Laux
- German Federal Institute for Risk Assessment (BfR), Department of Chemical and Product Safety, Max-Dohrn-Straße 8-10, 10589 Berlin, Germany
| | - Andreas Luch
- German Federal Institute for Risk Assessment (BfR), Department of Chemical and Product Safety, Max-Dohrn-Straße 8-10, 10589 Berlin, Germany
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