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Luo H, Zhang S, Zhong L. Ultraviolet germicidal irradiation: A prediction model to estimate UV-C-induced infectivity loss in single-strand RNA viruses. Environ Res 2024; 241:117704. [PMID: 37984783 DOI: 10.1016/j.envres.2023.117704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/13/2023] [Accepted: 11/14/2023] [Indexed: 11/22/2023]
Abstract
Ultraviolet germicidal irradiation (UVGI) disinfection technology is effective in inactivating microorganisms. However, its performance can vary against different microorganisms due to their diverse structural and genomic features. Thus, rapid predictions of UV (254 nm) inactivation kinetics are essential, particularly for highly infectious emerging pathogens, such as SARS-CoV-2, during the extemporary COVID-19 pandemic. In this study, aiming at single-strand RNA (ssRNA) viruses, an improved genomic model was introduced to predict the UV inactivation kinetics of viral genomes using genome sequence data. First, the overall virus infectivity loss in an aqueous matrix was estimated as the sum of damage to both the entire genome and the protein capsid. Then, the "UV rate constant ratio of aerosol and liquid" was used to convert the UV rate constant for viruses in a liquid-based matrix to an airborne state. The prediction model underwent both quantitative and qualitative validation using experimental data from this study and the literature. Finally, with the goal of mitigating potential airborne transmission of ssRNA viruses in indoor environments, this paper summarizes existing in-duct UVGI system designs and evaluates their germicidal performance. The prediction model may serve as a preliminary tool to assess the effectiveness of a UVGI system for emerging or unculturable viruses or to estimate the required UV dose when designing such a system.
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Affiliation(s)
- Hao Luo
- Department of Mechanical Engineering, University of Alberta, 9211-116 Street NW, Edmonton, Alberta, T6G 1H9, Canada
| | - Shuce Zhang
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, T6G 2G2, Canada
| | - Lexuan Zhong
- Department of Mechanical Engineering, University of Alberta, 9211-116 Street NW, Edmonton, Alberta, T6G 1H9, Canada.
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2
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Chawla H, Anand P, Garg K, Bhagat N, Varmani SG, Bansal T, McBain AJ, Marwah RG. A comprehensive review of microbial contamination in the indoor environment: sources, sampling, health risks, and mitigation strategies. Front Public Health 2023; 11:1285393. [PMID: 38074709 PMCID: PMC10701447 DOI: 10.3389/fpubh.2023.1285393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 10/25/2023] [Indexed: 12/18/2023] Open
Abstract
The quality of the indoor environment significantly impacts human health and productivity, especially given the amount of time individuals spend indoors globally. While chemical pollutants have been a focus of indoor air quality research, microbial contaminants also have a significant bearing on indoor air quality. This review provides a comprehensive overview of microbial contamination in built environments, covering sources, sampling strategies, and analysis methods. Microbial contamination has various origins, including human occupants, pets, and the outdoor environment. Sampling strategies for indoor microbial contamination include air, surface, and dust sampling, and various analysis methods are used to assess microbial diversity and complexity in indoor environments. The review also discusses the health risks associated with microbial contaminants, including bacteria, fungi, and viruses, and their products in indoor air, highlighting the need for evidence-based studies that can relate to specific health conditions. The importance of indoor air quality is emphasized from the perspective of the COVID-19 pandemic. A section of the review highlights the knowledge gap related to microbiological burden in indoor environments in developing countries, using India as a representative example. Finally, potential mitigation strategies to improve microbiological indoor air quality are briefly reviewed.
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Affiliation(s)
- Hitikk Chawla
- Institute for Cell Biology and Neuroscience, Goethe University Frankfurt, Frankfurt, Germany
| | - Purnima Anand
- Department of Microbiology, Bhaskaracharya College of Applied Sciences, University of Delhi, New Delhi, India
| | - Kritika Garg
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee, India
| | - Neeru Bhagat
- Department of Microbiology, Bhaskaracharya College of Applied Sciences, University of Delhi, New Delhi, India
| | - Shivani G. Varmani
- Department of Biomedical Science, Bhaskaracharya College of Applied Sciences, University of Delhi, New Delhi, India
| | - Tanu Bansal
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, India
| | - Andrew J. McBain
- School of Health Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Ruchi Gulati Marwah
- Department of Microbiology, Bhaskaracharya College of Applied Sciences, University of Delhi, New Delhi, India
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3
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Park S, Mistrick R, Sitzabee W, Rim D. Effect of ventilation strategy on performance of upper-room ultraviolet germicidal irradiation (UVGI) system in a learning environment. Sci Total Environ 2023; 899:165454. [PMID: 37467991 DOI: 10.1016/j.scitotenv.2023.165454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 06/22/2023] [Accepted: 07/08/2023] [Indexed: 07/21/2023]
Abstract
Upper-room ultraviolet germicidal irradiation (UVGI) system is recently in the limelight as a potentially effective method to mitigate the risk of airborne virus infection in indoor environments. However, few studies quantitatively evaluated the relationship between ventilation effectiveness and virus disinfection performance of a UVGI system. The objective of this study is to investigate the effects of ventilation strategy on detailed airflow distributions and UVGI disinfection performance in an occupied classroom. Three-dimensional computational fluid dynamics (CFD) simulations were performed for representative cooling, heating, and ventilation scenarios. The results show that when the ventilation rate is 1.1 h-1 (the minimum ventilation rate based on ASHRAE 62.1), enhancing indoor air circulation with the mixing fan notably improves the UVGI disinfection performance, especially for cooling with displacement ventilation and all-air-heating conditions. However, increasing indoor air mixing yields negligible effect on the disinfection performance for forced-convection cooling condition. The results also reveal that regardless of indoor thermal condition, disinfection effectiveness of a UVGI system increases as ventilation effectiveness is close to unity. Moreover, when the room average air speed is >0.1 m/s, upper-room UVGI system could yield about 90% disinfection effect for the aerosol size of 1 μm-10 μm. The findings of this study imply that upper-room UVGI systems in indoor environments (i.e., classrooms, hospitals) should be designed considering ventilation strategy and occupancy conditions, especially for occupied buildings with insufficient air mixing throughout the space.
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Affiliation(s)
- Seongjun Park
- Department of Architectural Engineering, Pennsylvania State University, United States of America.
| | - Richard Mistrick
- Architectural Engineering Department, Pennsylvania State University, 104 Engineering Unit A, University Park, PA 16802, United States of America.
| | - William Sitzabee
- Pennsylvania State University, 201 Physical Plant Building, University Park, PA 16802, United States of America.
| | - Donghyun Rim
- Architectural Engineering Department, Pennsylvania State University, 222 Engineering Unit A, University Park, PA 16802, United States of America.
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Ouyang H, Wang L, Sapkota D, Yang M, Morán J, Li L, Olson BA, Schwartz M, Hogan CJ, Torremorell M. Control technologies to prevent aerosol-based disease transmission in animal agriculture production settings: a review of established and emerging approaches. Front Vet Sci 2023; 10:1291312. [PMID: 38033641 PMCID: PMC10682736 DOI: 10.3389/fvets.2023.1291312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 10/26/2023] [Indexed: 12/02/2023] Open
Abstract
Transmission of infectious agents via aerosols is an ever-present concern in animal agriculture production settings, as the aerosol route to disease transmission can lead to difficult-to-control and costly diseases, such as porcine respiratory and reproductive syndrome virus and influenza A virus. It is increasingly necessary to implement control technologies to mitigate aerosol-based disease transmission. Here, we review currently utilized and prospective future aerosol control technologies to collect and potentially inactivate pathogens in aerosols, with an emphasis on technologies that can be incorporated into mechanically driven (forced air) ventilation systems to prevent aerosol-based disease spread from facility to facility. Broadly, we find that control technologies can be grouped into three categories: (1) currently implemented technologies; (2) scaled technologies used in industrial and medical settings; and (3) emerging technologies. Category (1) solely consists of fibrous filter media, which have been demonstrated to reduce the spread of PRRSV between swine production facilities. We review the mechanisms by which filters function and are rated (minimum efficiency reporting values). Category (2) consists of electrostatic precipitators (ESPs), used industrially to collect aerosol particles in higher flow rate systems, and ultraviolet C (UV-C) systems, used in medical settings to inactivate pathogens. Finally, category (3) consists of a variety of technologies, including ionization-based systems, microwaves, and those generating reactive oxygen species, often with the goal of pathogen inactivation in aerosols. As such technologies are typically first tested through varied means at the laboratory scale, we additionally review control technology testing techniques at various stages of development, from laboratory studies to field demonstration, and in doing so, suggest uniform testing and report standards are needed. Testing standards should consider the cost-benefit of implementing the technologies applicable to the livestock species of interest. Finally, we examine economic models for implementing aerosol control technologies, defining the collected infectious particles per unit energy demand.
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Affiliation(s)
- Hui Ouyang
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, United States
- Department of Mechanical Engineering, University of Texas-Dallas, Richardson, TX, United States
| | - Lan Wang
- Department of Veterinary Population Medicine, University of Minnesota, Saint Paul, MN, United States
| | - Deepak Sapkota
- Department of Mechanical Engineering, University of Texas-Dallas, Richardson, TX, United States
| | - My Yang
- Department of Veterinary Population Medicine, University of Minnesota, Saint Paul, MN, United States
| | - José Morán
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, United States
| | - Li Li
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, United States
| | - Bernard A. Olson
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, United States
| | - Mark Schwartz
- Department of Veterinary Population Medicine, University of Minnesota, Saint Paul, MN, United States
- Schwartz Farms, Sleepy Eye, MN, United States
| | - Christopher J. Hogan
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, United States
| | - Montserrat Torremorell
- Department of Veterinary Population Medicine, University of Minnesota, Saint Paul, MN, United States
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Kumar V, Bisht DS, Garg H. Modeling a UVC irradiation standalone system for inactivating Mycobacterium tuberculosis from indoor spaces. Appl Opt 2023; 62:6652-6660. [PMID: 37706797 DOI: 10.1364/ao.498255] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 07/27/2023] [Indexed: 09/15/2023]
Abstract
After the outbreak of the COVID-19 pandemic, a rise in demand has occurred for efficient designs of disinfection systems that utilize ultraviolet-C (UVC) radiation to inactivate airborne microorganisms effectively. This paper proposes what we believe to be a novel standalone system for inactivating Mycobacterium tuberculosis (which requires a higher dosage value than SARS-CoV-2) from a medium size room of 12.5f t×12.5f t×9f t. The structure consists of a UVC source at the center and a spiral pathway guiding the air around the UVC source, thus increasing the residence time of the aerosol particle. The top and bottom louvre and a hollow cylindrical cover (comprising four external cover segments) enclose the UVC source and prevent the danger of direct exposure to indoor occupants. The whole system is modeled in SolidWorks, and flux leakage was examined using the RayViz tool in SolidWorks. Optical/radiometric analysis in ray tracing software TracePro provided the UVC flux value at different locations of the standalone system. Flow simulation carried out in SolidWorks helped calculate aerosol particles' residence time at different airflow trajectories. The designed standalone system demonstrated the capability of delivering 1.87 times more dosage than is required to inactivate Mycobacterium tuberculosis from the ambient air. The standalone system achieves a ventilation rate, i.e., air changes per hour value of 10, according to guidelines from the Council of Scientific & Industrial Research, India.
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Moghadam TT, Ochoa Morales CE, Lopez Zambrano MJ, Bruton K, O'Sullivan DTJ. Energy efficient ventilation and indoor air quality in the context of COVID-19 - A systematic review. Renew Sustain Energy Rev 2023; 182:113356. [PMID: 37220488 PMCID: PMC10186986 DOI: 10.1016/j.rser.2023.113356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 05/02/2023] [Accepted: 05/08/2023] [Indexed: 05/25/2023]
Abstract
New COVID-19 ventilation guidelines have resulted in higher energy consumption to maintain indoor air quality (IAQ), and energy efficiency has become a secondary concern. Despite the significance of the studies conducted on COVID-19 ventilation requirements, a comprehensive investigation of the associated energy challenges has not been discussed. This study aims to present a critical systematic review of the Coronavirus viral spreading risk mitigation through ventilation systems (VS) and its relation to energy use. COVID-19 heating, ventilation and air conditioning (HVAC)-related countermeasures proposed by industry professionals have been reviewed and their influence on operating VS and energy consumption have also been discussed. A critical review analysis was then conducted on publications from 2020 to 2022. Four research questions (RQs) have been selected for this review concerning i) maturity of the existing literature, ii) building types and occupancy profile, iii) ventilation types and effective control strategies and iv) challenges and related causes. The results reveal that employing HVAC auxiliary equipment is mostly effective and increased fresh air supply is the most significant challenge associated with increased energy consumption due to maintaining IAQ. Future studies should focus on novel approaches toward solving the apparently conflicting objectives of minimizing energy consumption and maximizing IAQ. Also, effective ventilation control strategies should be assessed in various buildings with different occupancy densities. The implications of this study can be useful for future development of this topic not only to enhance the energy efficiency of the VS but also to enable more resiliency and health in buildings.
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Affiliation(s)
- Talie T Moghadam
- Intelligent Efficiency Research Group (IERG), University College Cork, Cork, Ireland
| | | | | | - Ken Bruton
- Intelligent Efficiency Research Group (IERG), University College Cork, Cork, Ireland
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7
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de Oliveira SV, Neves FDD, dos Santos DC, Monteiro MBB, Schaufelberger MS, Motta BN, de Oliveira IP, Setúbal Destro Rodrigues MF, Franco ALDS, Cecatto RB. The effectiveness of phototherapy for surface decontamination against SARS-Cov-2. A systematic review. J Biophotonics 2023; 16:e202200306. [PMID: 36560919 PMCID: PMC9880673 DOI: 10.1002/jbio.202200306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
COVID-19 appeared in December 2019, needing efforts of science. Besides, a range of light therapies (photodynamic therapy, ultraviolet [UV], laser) has shown scientific alternatives to conventional decontamination therapies. Investigating the efficacy of light-based therapies for environment decontamination against SARS-CoV2, a PRISMA systematic review of Phototherapies against SARS-CoV or MERS-CoV species discussing changes in viral RT-PCR was done. After searching MEDLINE/PubMed, EMBASE, and Literatura Latino-Americana e do Caribe em Ciências da Saúde we have found studies about cell cultures irradiation (18), blood components irradiation (10), N95 masks decontamination (03), inanimate surface decontamination (03), aerosols decontamination (03), hospital rooms irradiation (01) with PDT, LED, and UV therapy. The best quality results showed an effective low time and dose UV irradiation for environments and inanimate surfaces without human persons as long as the devices have safety elements dependent on the surfaces, viral charge, humidity, radiant exposure. To interpersonal contamination in humans, PDT or LED therapy seems very promising and are encouraged.
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Affiliation(s)
- Susyane Vieira de Oliveira
- Post Graduate Program Biophotonics Applied to Health Sciences, Universidade Nove de Julho/UNINOVESao PauloBrazil
| | | | | | | | | | | | | | | | | | - Rebeca Boltes Cecatto
- Post Graduate Program Biophotonics Applied to Health Sciences, Universidade Nove de Julho/UNINOVESao PauloBrazil
- Instituto do Cancer do Estado de Sao Paulo, School of Medicine of the University of Sao PauloSao PauloBrazil
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8
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Chang Y, Ai Z, Ye J, Ma G. A cost-effectiveness assessment of the operational parameters of central HVAC systems during pandemics. Build Simul 2023; 16:667-682. [PMID: 37101942 PMCID: PMC10040913 DOI: 10.1007/s12273-023-1000-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 01/19/2023] [Accepted: 02/05/2023] [Indexed: 06/19/2023]
Abstract
The present study develops a cost-effectiveness assessment model to analyze the performance of major operational parameters of central HVAC systems in terms of airborne transmission risk, energy consumption, and medical and social cost. A typical multi-zone building model with a central HVAC system is built numerically, and the effect of outdoor air (OA) ratio (from 30% to 100%) and filtration level (MERV 13, MERV 16, and HEPA) are assessed under the conditions of five climate zones in China. Compared with the baseline case with 30% OA and MERV 13 filtration, the airborne transmission risk in zones without infector is negligibly reduced with the increase in OA ratio and the upgrade of filtration level, owing to their slight modification on the equivalent ventilation rate of virus-free air. However, depending on climate zone, a 10% increase in OA ratio results in 12.5%-78.6% and 0.1%-8.6% increase in heating and cooling energy consumption, respectively, while an upgrade of filtration level to MERV 16 and HEPA results in an increase of 0.08%-0.2% and 1.4%-2.6%, respectively. Overall, when compared to the use of 100% OA ratio and HEPA filtration, the application of 30% or 40% OA ratio and MERV 13 filtration would save annually an energy and facility related cost of $29.4 billion in China, though giving an increase of approximately $0.1 billion on medical and social cost from the increased number of confirmed cases. This study provides basic method and information for the formulation of cost-effective operational strategies of HVAC systems coping with the airborne transmission, especially in resource-limited regions.
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Affiliation(s)
- Yufan Chang
- Department of Building Environment and Energy, College of Civil Engineering, Hunan University, Changsha, Hunan, China
- National Center for International Research Collaboration in Building Safety and Environment, Hunan University, Changsha, Hunan, China
| | - Zhengtao Ai
- Department of Building Environment and Energy, College of Civil Engineering, Hunan University, Changsha, Hunan, China
- National Center for International Research Collaboration in Building Safety and Environment, Hunan University, Changsha, Hunan, China
| | - Jinjun Ye
- Department of Building Environment and Energy, College of Civil Engineering, Hunan University, Changsha, Hunan, China
- National Center for International Research Collaboration in Building Safety and Environment, Hunan University, Changsha, Hunan, China
| | - Guochuan Ma
- China Southwest Architectural Design and Research Institute, Chengdu, Sichuan, China
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Liu X, Qin Z, Wang L, Xie X, Fu Y, Yu J, Liang Z, He X, Li J, Dai H, Yao J, Wu Q, Xiao W, Zhu L, Wan C, Zhang B, Zhao W. A simple and effective aerosol pathogen disinfection test for a flowing air disinfector. J Biosaf Biosecur 2023; 5:32-38. [PMID: 36936134 PMCID: PMC10014499 DOI: 10.1016/j.jobb.2023.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 02/25/2023] [Accepted: 02/27/2023] [Indexed: 03/17/2023] Open
Abstract
Aerosol transmission is an important disease transmission route and has been especially pertinent to hospital and biosafety laboratories during the SARS-CoV-2 pandemic. The thermal resistance of airborne SARS-CoV-2 is lower than that of Bacillus subtilis spores, which are often used to test the effectiveness of SARS-CoV-2 and other pathogen disinfection methods. Herein, we propose a new method to test the disinfection ability of a flowing air disinfector (a digital electromagnetic induction air heater) using B. subtilis spores. The study provides an alternative air disinfection test method. The new test system combined an aerosol generator and a respiratory filter designed in-house and could effectively recover spores on the filter membrane at the air outlet after passing through the flowing air disinfector. The total number of bacterial spores used in the test was within the range of 5 × 105-5 × 106 colony-forming units (CFUs) specified in the technical standard for disinfection. The calculation was based on the calculation method in Air Disinfection Effect Appraisal Test in Technical Standard for Disinfection (2002 Edition). At an air speed of 3.5 m/s, we used a digital electromagnetic induction air heater to disinfect flowing air containing 4.100 × 106 CFUs of B. subtilis spores and determined that the minimum disinfection temperature was 350 °C for a killing rate of 99.99%. At 400 °C, additional experiments using higher spore concentrations (4.700 × 106 ± 1.871 × 105 CFU) and a higher airspeed (4 m/s) showed that the killing rate remained>99.99%. B. subtilis spores, as a biological indicator for testing the efficiency of dry-heat sterilization, were killed by the high temperatures used in this system. The proposed method used to test the flowing air disinfector is simple, stable, and effective. This study provides a reference for the development of test systems that can assess the disinfection ability of flowing air disinfectors.
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Affiliation(s)
- Xuling Liu
- BSL-3 Laboratory (Guangdong), Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - Zhiran Qin
- BSL-3 Laboratory (Guangdong), Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - Linqing Wang
- BSL-3 Laboratory (Guangdong), Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - Xiaoting Xie
- BSL-3 Laboratory (Guangdong), Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - Yifang Fu
- Guangzhou SaveTech Co., Ltd., Guangzhou 510070, China
| | - Jianhai Yu
- BSL-3 Laboratory (Guangdong), Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - Zuxin Liang
- BSL-3 Laboratory (Guangdong), Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - Xiaoen He
- BSL-3 Laboratory (Guangdong), Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - Jingshu Li
- BSL-3 Laboratory (Guangdong), Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - Hong Dai
- Guangzhou Taojin Electronic Commerce Co., Ltd., Guangzhou 510289, China
| | - Jinxiu Yao
- People's Hospital of Yangjiang, Yangjiang 529500, China
| | - Qinghua Wu
- BSL-3 Laboratory (Guangdong), Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - Weiwei Xiao
- BSL-3 Laboratory (Guangdong), Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - Li Zhu
- BSL-3 Laboratory (Guangdong), Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - Chengsong Wan
- BSL-3 Laboratory (Guangdong), Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - Bao Zhang
- BSL-3 Laboratory (Guangdong), Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - Wei Zhao
- BSL-3 Laboratory (Guangdong), Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, China
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10
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Beswick A, Brookes J, Rosa I, Bailey C, Beynon C, Stagg S, Bennett N. Room-Based Assessment of Mobile Air Cleaning Devices Using a Bioaerosol Challenge. Appl Biosaf 2023; 28:1-10. [PMID: 36895580 PMCID: PMC9991428 DOI: 10.1089/apb.2022.0028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Introduction The widespread transmission of the SARS-CoV-2 virus has increased scientific and societal interest in air cleaning technologies, and their potential to mitigate the airborne spread of microorganisms. Here we evaluate room scale use of five mobile air cleaning devices. Methods A selection of air cleaners, containing high efficiency filtration, was tested using an airborne bacteriophage challenge. Assessments of bioaerosol removal efficacy were undertaken using a decay measurement approach over 3 h, with air cleaner performance compared with bioaerosol decay rate without an air cleaner in the sealed test room. Evidence of chemical by-product emission was also checked, as were total particle counts. Results Bioaerosol reduction, exceeding natural decay, was observed for all air cleaners. Reductions ranged between devices from <2-log per m3 room air for the least effective, to a >5-log reduction for the most efficacious systems. One system generated detectable ozone within the sealed test room, but ozone was undetectable when the system was run in a normally ventilated room. Total particulate air removal trends aligned with measured airborne bacteriophage decline. Discussion Air cleaner performance differed, and this could relate to individual air cleaner flow specifications as well as test room conditions, such as air mixing during testing. However, measurable reductions in bioaerosols, beyond natural airborne decay rate, were observed. Conclusion Under the described test conditions, air cleaners containing high efficiency filtration significantly reduced bioaerosol levels. The best performing air cleaners could be investigated further with improved assay sensitivity, to enable measurement of lower residual levels of bioaerosols.
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Affiliation(s)
- Alan Beswick
- Health and Safety Executive Science and Research Centre, Buxton, United Kingdom
| | - Jodi Brookes
- Health and Safety Executive Science and Research Centre, Buxton, United Kingdom
| | - Iwona Rosa
- Health and Safety Executive Science and Research Centre, Buxton, United Kingdom
| | - Claire Bailey
- Health and Safety Executive Science and Research Centre, Buxton, United Kingdom
| | | | - Stephen Stagg
- Health and Safety Executive Science and Research Centre, Buxton, United Kingdom
| | - Neil Bennett
- Health and Safety Executive Science and Research Centre, Buxton, United Kingdom
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11
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Lv M, Huang J, Chen H, Zhang TT. An excimer lamp to provide far-ultraviolet C irradiation for dining-table disinfection. Sci Rep 2023; 13:381. [PMID: 36611088 PMCID: PMC9825099 DOI: 10.1038/s41598-023-27380-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 01/02/2023] [Indexed: 01/09/2023] Open
Abstract
Dining tables may present a risk to diners by transmitting bacteria and/or viruses. Currently, there is a lack of an environmental-friendly and convenient means to protect diners when they are sitting together. This investigation constructed far-UVC excimer lamps to disinfect dining-table surfaces. The lamps were mounted at different heights and orientations, and the irradiance on table surfaces was measured. The irradiation doses to obtain different inactivation efficiencies for Escherichia coli (E. coli) were provided. In addition, numerical modeling was conducted for irradiance and the resulting inactivation efficiency. The surface-to-surface (S2S) model was validated with the measured irradiance. The germicidal performance of far-UVC irradiation, the far-UVC doses to which diners were exposed, and the risk of exposure to the generated ozone were evaluated. The results revealed that an irradiation dose of 12.8 mJ/cm2 can disinfect 99.9% of E. coli on surfaces. By varying the lamp irradiance output, the number and positions of the lamps, the far-UVC irradiation can achieve a 3-log reduction for a dining duration of 5 min. Besides, the far-UVC lamp has a low damage risk to diners when achieving an effective inactivation rate. Moreover, there is virtually no ozone exposure risk in a mechanically ventilated dining hall.
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Affiliation(s)
- Mengqiang Lv
- Tianjin Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Jin Huang
- Tianjin Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Haofu Chen
- Tianjin Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Tengfei Tim Zhang
- Tianjin Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin, China.
- School of Civil Engineering, Dalian University of Technology, Dalian, China.
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12
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Al-Rawi M, Al-Jumaily AM, Lazonby A. Did You Just Cough? Visualization of Vapor Diffusion in an Office Using Computational Fluid Dynamics Analysis. Int J Environ Res Public Health 2022; 19:9928. [PMID: 36011558 PMCID: PMC9408159 DOI: 10.3390/ijerph19169928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/05/2022] [Accepted: 08/10/2022] [Indexed: 06/15/2023]
Abstract
Awareness of indoor air quality (IAQ) in crowded places such as schools and offices has increased since 2020 due to the COVID-19 pandemic. In addition, countries' shifting away from containment and towards living with COVID-19 is expected to increase demand for risk mitigation via air-purification devices. In this work, we use Computational Fluid Dynamics (CFD) analysis to investigate the impact of adding an air-purification technology on airflow in an enclosed space. We model a Polyester Filter and UV light (PFUV) dehumidifier in an office with two occupants: one infected with an airborne infectious disease, such as COVID-19; and the other uninfected. We compare three cases where the infected occupant coughs: with no device, and with the device at two different orientations. We construct a CFD model using ANSYS® 2021 Fluent and the Discrete Phase Model (DPM) for the particle treatment. Thermal comfort is assessed using the Testo 400 IAQ and comfort kit. We find that both the device operation and the placement alter the airflow contours, significantly reducing the potential for the uninfected occupant to inhale the vapour expelled by the infected occupant, potentially impacting the likelihood of disease transmission. The device improved thermal comfort measured by Predicted Mean Vote (PMV), Predicted Percentage Dissatisfied (PPD).
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Affiliation(s)
- Mohammad Al-Rawi
- Centre for Engineering and Industrial Design (CEID), Waikato Institute of Technology, Hamilton 3240, New Zealand
| | - Ahmed M. Al-Jumaily
- Institute of Biomedical Technologies (IBTec), Auckland University of Technology (AUT), Auckland 1010, New Zealand
| | - Annette Lazonby
- Faculty of Business and Economics, The University of Auckland, Auckland 1010, New Zealand
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13
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Zhang L, Guo Y, Chang X, Yao Z, Wei X, Feng Z, Zhang D, Zhou Q, Wang X, Luo H. In-duct grating-like dielectric barrier discharge system for air disinfection. J Hazard Mater 2022; 435:129075. [PMID: 35650753 PMCID: PMC9072810 DOI: 10.1016/j.jhazmat.2022.129075] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 05/01/2022] [Accepted: 05/02/2022] [Indexed: 05/04/2023]
Abstract
In the context of spreading Coronavirus disease 2019 (COVID-19), the combination of heating, ventilation, and air-conditioning (HVAC) system with air disinfection device is an effective way to reduce transmissible infections. Atmospheric-pressure non-equilibrium plasma is an emerging technique for fast pathogen aerosol abatement. In this work, in-duct disinfectors based on grating-like dielectric barrier discharge (DBD) plasmas with varied electrode arrangements were established and evaluated. The highest airborne bacterial inactivation efficiency was achieved by 'vertical' structure, namely when aerosol was in direct contact with the discharge region, at a given discharge power. For all reactors, the efficiency was linearly correlated to the discharge power (R2 =0.929-0.994). The effects of environmental factors were examined. Decreased airflow rates boosted the efficiency, which reached 99.8% at the velocity of 0.5 m/s with an aerosol residence time of ~3.6 ms. Increasing humidity (relative humidity (RH)=20-60%) contributed to inactivation efficacy, while high humidity (RH=70%-90%) led to a saturated efficiency, possibly due to the disruption of discharge uniformity. As suggested by the plasma effluent treatment and scavenger experiments, gaseous short-lived chemical species or charged particles were concluded as the major agents accounting for bacterial inactivation. This research provides new hints for air disinfection by DBD plasmas.
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Affiliation(s)
- Liyang Zhang
- Department of Electrical Engineering, Tsinghua University, Beijing, China
| | - Yuntao Guo
- Department of Electrical Engineering, Tsinghua University, Beijing, China.
| | - Xuanyu Chang
- Marine Design and Research Institute of China (MARIC), Shanghai, China
| | - Zenghui Yao
- School of Electrical and Electronic Engineering, North China Electric Power University, Beijing, China
| | - Xiaodong Wei
- Marine Design and Research Institute of China (MARIC), Shanghai, China
| | - Zihao Feng
- Department of Electrical Engineering, Tsinghua University, Beijing, China
| | - Dongheyu Zhang
- Department of Electrical Engineering, Tsinghua University, Beijing, China
| | - Qun Zhou
- Department of Chemistry, Tsinghua University, Beijing, China
| | - Xinxin Wang
- Department of Electrical Engineering, Tsinghua University, Beijing, China
| | - Haiyun Luo
- Department of Electrical Engineering, Tsinghua University, Beijing, China.
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14
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Ghaddar N, Ghali K. Ten questions concerning the paradox of minimizing airborne transmission of infectious aerosols in densely occupied spaces via sustainable ventilation and other strategies in hot and humid climates. Build Environ 2022; 214:108901. [PMID: 35197667 PMCID: PMC8853966 DOI: 10.1016/j.buildenv.2022.108901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 02/07/2022] [Accepted: 02/12/2022] [Indexed: 05/14/2023]
Abstract
Airborne disease transmission in indoor spaces and resulting cross-contamination has been a topic of broad concern for years - especially recently with the outbreak of COVID-19. Global recommendations on this matter consist of increasing the outdoor air supply in the aim of diluting the indoor air. Nonetheless, a paradoxical relationship has risen between increasing amount of outdoor air and its impact on increased energy consumption - especially densely occupied spaces. The paradox is more critical in hot and humid climates, where large amounts of energy are required for the conditioning of the outdoor air. Therefore, many literature studies investigated new strategies for the mitigation of cross-contamination with little-to-no additional cost of energy. These strategies mainly consist of the dilution and/or the capture and removal of contaminants at the levels of macroenvironment room air and occupant-adjacent microenvironment. On the macroenvironment level, the dilution occurs by the supply of large amounts of outdoor air in a sustainable way using passive cooling systems, and the removal of contaminants happens via filtering. Similarly, the microenvironment of the occupant can be diluted using localized ventilation techniques, and contaminants can be captured and removed by direct exhaust near the source of contamination. Thus, this work answers ten questions that explore the most prevailing technologies from the above-mentioned fronts that are used to mitigate cross-contamination in densely occupied spaces located in hot and humid climates at minimal energy consumption. The paper establishes a basis for future work and insights for new research directives for macro and microenvironment approaches.
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Affiliation(s)
- Nesreen Ghaddar
- Mechanical Engineering Department, American University of Beirut, P.O. Box 11-0236, Beirut, 1107-2020, Lebanon
| | - Kamel Ghali
- Mechanical Engineering Department, American University of Beirut, P.O. Box 11-0236, Beirut, 1107-2020, Lebanon
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15
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Al-Rawi M, Lazonby A, Smith C. Prototyping a low-cost residential air quality device using ultraviolet germicidal irradiation (UVGI) light. HardwareX 2022; 11:e00251. [PMID: 35509924 PMCID: PMC9058593 DOI: 10.1016/j.ohx.2021.e00251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 11/23/2021] [Accepted: 12/07/2021] [Indexed: 06/14/2023]
Abstract
Many New Zealand residential dwellings suffer from dampness and fungi during the winter, which can cause respiratory health problems. This can be due to poor insulation and ventilation, and the situation worsens when residents cannot afford to heat the dwelling. The main aim of this paper is to modify an existing dehumidifier so that it can remove moisture, heat the living space and reduce fungi growth and bacteria. To achieve that, we installed ultraviolet germicidal lights (UVGI) in an existing dehumidifier with a total cost of USD $150.7 (NZD $213.76). The UVGI lights are known to be efficient in destroying the DNA of fungi and bacteria. The results show that the device reduced the fungi growth and did increase the room temperature because the dehumidifier captured two litres of water over 24 h of testing. The proposed device did achieve a reduction in particulate matters, from 0.9 μ g / m 3 to 0.14 μ g / m 3 and an acceptable range of relative humidity below 50%, which reduces the favourable conditions for fungi growth. Therefore, our proposed low-cost device does improve the indoor air quality (IAQ) in the living space.
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Affiliation(s)
- Mohammad Al-Rawi
- Centre for Engineering and Industrial Design, Waikato Institute of Technology (Wintec), Hamilton, New Zealand
| | - Annette Lazonby
- Faculty of Business and Economics, The University of Auckland, Auckland, New Zealand
| | - Callan Smith
- Designer at Modern Transport Engineers, Hamilton, New Zealand
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16
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Skudra A, Revalde G, Zajakina A, Mezule L, Spunde K, Juhna T, Rancane K. UV inactivation of Semliki Forest virus and bacteria by alternative light sources. Journal of Photochemistry and Photobiology 2022; 10:100120. [PMID: 35437519 PMCID: PMC8994679 DOI: 10.1016/j.jpap.2022.100120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The quick spreading of the SARS-CoV-2 virus, initiating the global pandemic with a significant impact on economics and health, highlighted an urgent need for effective and sustainable restriction mechanisms of pathogenic microorganisms. UV-C radiation, causing inactivation of many viruses and bacteria, is one of the tools for disinfection of different surfaces, liquids, and air; however, mainly mercury 254 nm line is commonly used for it. In this paper, we report our results of the experiments with newly elaborated special type polychromatic non-mercury UV light sources, having spectral lines in the spectral region from 190 nm to 280 nm. Inactivation tests were performed with both Escherichia coli (E.coli) bacteria and Semliki Forest virus (SFV) as a representative of human enveloped RNA viruses. In addition, the effect of prepared lamps on virus samples in liquid and dry form (dried virus-containing solution) was tested. Reduction of 4 log10 of E.coli was obtained after 10 min of irradiation with both thallium-antimony and arsenic high-frequency electrodeless lamps. High reduction results for the arsenic light source demonstrated sensitivity of E. coli to wavelengths below 230 nm, including spectral lines around 200 nm. For the Semliki Forest virus, the thallium-antimony light source showed virus inactivation efficiency with a high virus reduction rate in the range of 3.10 to > 4.99 log10 within 5 min of exposure. Thus, the new thallium-antimony light source showed the most promising disinfection effect in bacteria and viruses, and arsenic light sources for bacteria inactivation, opening doors for many applications in disinfection systems, including for pathogenic human RNA viruses.
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17
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Shamim JA, Hsu WL, Daiguji H. Review of component designs for post-COVID-19 HVAC systems: Possibilities and challenges. Heliyon 2022; 8:e09001. [PMID: 35224237 PMCID: PMC8863315 DOI: 10.1016/j.heliyon.2022.e09001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 09/16/2021] [Accepted: 02/18/2022] [Indexed: 11/01/2022] Open
Abstract
The globally occurring recurrent waves of the COVID-19 pandemic, primarily caused by the transmission of aerosolized droplets from an infected person to a healthy person in the indoor environment, has led to the urgency of designing new modes of indoor ventilation. To prevent cross-contaminations due to airborne viruses, bacteria, and other pollutants in indoor environments, heating ventilation and air-conditioning (HVAC) systems need to be redesigned with anti-pandemic components. The three vital anti-pandemic components for the post-COVID-19 HVAC systems, as identified by the authors, are: a biological contaminant inactivation unit, a volatile organic compound decomposition unit, and an advanced air filtration unit. The purpose of the current article is to provide an overview of the latest research outcomes toward designing these anti-pandemic components and pointing out the future promises and challenges. In addition, the role of personalized ventilation in minimizing the risk of indoor cross-contamination by employing various air terminal devices is discussed. The authors believe that this article will encourage HVAC designers to develop effective anti-pandemic components to minimize the indoor airborne transmission.
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Affiliation(s)
- Jubair A Shamim
- Department of Mechanical Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Wei-Lun Hsu
- Department of Mechanical Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Hirofumi Daiguji
- Department of Mechanical Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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18
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Vlaskin MS. Review of air disinfection approaches and proposal for thermal inactivation of airborne viruses as a life-style and an instrument to fight pandemics. Appl Therm Eng 2022; 202:117855. [PMID: 34867067 PMCID: PMC8628600 DOI: 10.1016/j.applthermaleng.2021.117855] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 10/20/2021] [Accepted: 11/24/2021] [Indexed: 05/02/2023]
Abstract
COVID-19 (Coronavirus Disease 2019) pandemic highlighted the importance of air biosecurity because SARS-CoV-2 is mainly transmitted from person to person via airborne droplets. Preventing infectious droplets from entering the body is one of the best ways to protect against infection. This paper reviews the transmission patterns of airborne pathogens and air disinfection methods. A particular emphasis is put on studies devoted to the thermal inactivation of viruses. These reviews reveal that air heat treatment has not been seriously considered as a possible air disinfection approach. Simple calculations show that the energy input required for thermal disinfection of human's air daily consumption is almost the same as for daily water consumption (by heat treatment from room temperature to 100 °C). Moreover, it is possible to organize a continuous heat recovery from the air already heated during disinfection to the inlet air, thus significantly increasing the energy efficiency. Therefore, I propose a solution for the thermal inactivation of airborne pathogens based on air heating and its subsequent cooling in a heat exchanger with heat recovery. Such a solution could be used to create mobile personal and stationary indoor air disinfectors, as well as heating, ventilation, and air conditioning systems. Thermal disinfection of air to breathe might one day be part of people's daily life like thermal disinfection of drinking water. Aside from limiting infectious disease transmission, thermal inactivation might be the basis for developing inhaled vaccines using thermally inactivated whole pathogens.
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Affiliation(s)
- Mikhail S Vlaskin
- Joint Institute for High Temperatures of the Russian Academy of Sciences, 13/2 Izhorskaya St, Moscow 125412, Russia
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19
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Feng Z, Cao SJ, Haghighat F. Removal of SARS-CoV-2 using UV+Filter in built environment. Sustain Cities Soc 2021; 74:103226. [PMID: 34367884 PMCID: PMC8329429 DOI: 10.1016/j.scs.2021.103226] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 07/31/2021] [Accepted: 07/31/2021] [Indexed: 05/03/2023]
Abstract
Air cleaning is an effective and reliable method in indoor airborne SARS-CoV-2 (Severe Acute Respiratory Syndrome Corona-Virus 2) control, with ability of aerosol removal or disinfection. However, traditional air cleaning systems (e.g. fibrous filter, electrostatic removal system) have some risks in operation process, including re-aerosolization and electric breakdown. To avoid these risks, the current study proposed an UV+Filter (ultraviolet and fibrous pleated filter) system to efficiently capture airborne SARS-CoV-2 aerosols and deactivate them in filter medium. It is challenging to quantitatively design UV+Filter due to complex characteristics of SARS-CoV-2 aerosols (e.g. aerodynamic size, biological susceptibility) and hybrid filtration/disinfection processes. This study numerically investigated the overall performances of different air cleaning devices (e.g. Fibrous-filter, UV+Filter, two-stage ESP (electrostatic precipitator) et al.) for control of SARS-CoV-2 aerosols and compared them in term of filtration efficiency, energy consumption and secondary pollution. The prediction of developed models was validated with the experimental data from literature. UV+Filter is the most reliable and safest, while its energy consumption is highest. The newly proposed design method of air cleaning systems could provide essential tools for airborne diseases control.
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Affiliation(s)
- Zhuangbo Feng
- School of Architecture, Southeast University, 2 Sipailou, Nanjing, 210096, China
| | - Shi-Jie Cao
- School of Architecture, Southeast University, 2 Sipailou, Nanjing, 210096, China
- Global Centre for Clean Air Research (GCARE), Department of Civil and Environmental Engineering, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, United Kingdom
| | - Fariborz Haghighat
- Department of Building, Civil and Environmental Engineering, Concordia University, Montreal, Canada
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20
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Joo T, Rivera-Rios JC, Alvarado-Velez D, Westgate S, Ng NL. Formation of Oxidized Gases and Secondary Organic Aerosol from a Commercial Oxidant-Generating Electronic Air Cleaner. Environ Sci Technol Lett 2021; 8:691-698. [PMID: 37566381 PMCID: PMC8315241 DOI: 10.1021/acs.estlett.1c00416] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/29/2021] [Accepted: 07/02/2021] [Indexed: 05/04/2023]
Abstract
The COVID-19 pandemic increased the demand for indoor air cleaners. While some commercial electronic air cleaners can be effective in reducing primary pollutants and inactivating bioaerosol, studies on the formation of secondary products from oxidation chemistry during their use are limited. Here, we measured oxygenated volatile organic compounds (OVOCs) and the chemical composition of particles generated from a hydroxyl radical generator in an office. During operation, enhancements in OVOCs, especially low-molecular-weight organic acids, were detected. Rapid increases in particle number and mass concentrations were observed, corresponding to the formation of highly oxidized secondary organic aerosol (SOA) (O:C ∼ 1.3), with an enhanced signal at m/z 44 (CO2+) in the organic mass spectra. These results suggest that organic acids generated during VOC oxidation contributed to particle nucleation and SOA formation. Nitrate, sulfate, and chloride also increased during the oxidation without a corresponding increase in ammonium, suggesting organic nitrate, organic sulfate, and organic chloride formation. As secondary species are reported to have detrimental health effects, further studies should not be limited to the inactivation of bioaerosol or reduction of particular VOCs, but should also evaluate potential OVOCs and SOA formation from electronic air cleaners in different indoor environments.
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Affiliation(s)
- Taekyu Joo
- School of Earth and Atmospheric Sciences,
Georgia Institute of Technology, Atlanta, Georgia 30332,
United States
| | - Jean C. Rivera-Rios
- School of Chemical and Biomolecular Engineering,
Georgia Institute of Technology, Atlanta, Georgia 30332,
United States
| | - Daniel Alvarado-Velez
- School of Chemical and Biomolecular Engineering,
Georgia Institute of Technology, Atlanta, Georgia 30332,
United States
| | - Sabrina Westgate
- School of Chemical and Biomolecular Engineering,
Georgia Institute of Technology, Atlanta, Georgia 30332,
United States
| | - Nga Lee Ng
- School of Earth and Atmospheric Sciences,
Georgia Institute of Technology, Atlanta, Georgia 30332,
United States
- School of Chemical and Biomolecular Engineering,
Georgia Institute of Technology, Atlanta, Georgia 30332,
United States
- School of Civil and Environmental Engineering,
Georgia Institute of Technology, Atlanta, Georgia 30332,
United States
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