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Myung H, Joung YS. Contribution of Particulates to Airborne Disease Transmission and Severity: A Review. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:6846-6867. [PMID: 38568611 DOI: 10.1021/acs.est.3c08835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/24/2024]
Abstract
The emergence of coronavirus disease 2019 (COVID-19) has catalyzed great interest in the spread of airborne pathogens. Airborne infectious diseases are classified into viral, bacterial, and fungal infections. Environmental factors can elevate their transmission and lethality. Air pollution has been reported as the leading environmental cause of disease and premature death worldwide. Notably, ambient particulates of various components and sizes are harmful pollutants. There are two prominent health effects of particles in the atmosphere: (1) particulate matter (PM) penetrates the respiratory tract and adversely affects health, such as heart and respiratory diseases; and (2) bioaerosols of particles act as a medium for the spread of pathogens in the air. Particulates contribute to the occurrence of infectious diseases by increasing vulnerability to infection through inhalation and spreading disease through interactions with airborne pathogens. Here, we focus on the synergistic effects of airborne particulates on infectious disease. We outline the concepts and characteristics of bioaerosols, from their generation to transformation and circulation on Earth. Considering that microorganisms coexist with other particulates as bioaerosols, we investigate studies examining respiratory infections associated with airborne PM. Furthermore, we discuss four factors (meteorological, biological, physical, and chemical) that may impact the influence of PM on the survival of contagious pathogens in the atmosphere. Our review highlights the significant role of particulates in supporting the transmission of infectious aerosols and emphasizes the need for further research in this area.
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Affiliation(s)
- Hyunji Myung
- Department of Mechanical Systems Engineering, Sookmyung Women's University, 100, Cheongpa-ro 47-gil, Yongsan-gu, Seoul 04310, Republic of Korea
| | - Young Soo Joung
- Department of Mechanical Systems Engineering, Sookmyung Women's University, 100, Cheongpa-ro 47-gil, Yongsan-gu, Seoul 04310, Republic of Korea
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Kvasnicka J, Cohen Hubal EA, Diamond ML. Modeling clothing as a secondary source of exposure to SVOCs across indoor microenvironments. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2024; 34:376-385. [PMID: 38129669 PMCID: PMC11144090 DOI: 10.1038/s41370-023-00621-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 11/27/2023] [Accepted: 11/28/2023] [Indexed: 12/23/2023]
Abstract
BACKGROUND Evidence suggests that clothing can influence human exposure to semi-volatile organic compounds (SVOCs) through transdermal uptake and inhalation. OBJECTIVES The objectives of this study were [1] to investigate the potential for clothing to function as a transport vector and secondary source of gas-phase SVOCs across indoor microenvironments, [2] to elucidate how clothing storage, wear, and laundering can influence the dynamics of transdermal uptake, and [3] to assess the potential for multiple human occupants to influence the multimedia dynamics of SVOCs indoors. METHODS A computational modeling framework (ABICAM) was expanded, applied, and evaluated by simulating and augmenting two "real-world" chamber experiments. A primary strength of this framework was its representation of occupants and their clothing as unique entities with the potential for location changes. RESULTS Estimates of transdermal uptake of diethyl phthalate (DEP) and di(n-butyl) phthalate (DnBP) were generally consistent with those extrapolated from measured concentrations of urinary metabolites, and those predicted by two other mechanistic models. ABICAM predicted that clean clothing (long sleeves, long pants, and socks, 100% cotton, 1 mm thick) readily accumulated DEP (6900-9700 μg) and DnBP (4500-4800 μg) from the surrounding chamber air over 6 h of exposure to average concentrations of 233 (DEP) and 114 (DnBP) μg·m-3. Because of their high capacity, clean clothing also effectively minimized transdermal uptake. In addition, ABICAM predicted that contaminated clothing functioned as a vector for transporting DEP and DnBP across indoor microenvironments and reemitted 13-80% (DEP) and 3-27% (DnBP) of the accumulated masses over 48 h. SIGNIFICANCE Though the estimated secondary inhalation exposures from contaminated clothing were low compared to the corresponding primary exposures, these secondary exposures could be accentuated in other contexts, for example, involving longer timeframes of clothing storage, multiple occupants wearing contaminated clothing, and/or repeated instances of clothing-mediated transport of contaminants (e.g., from an occupational setting). IMPACT This modeling study reaffirms the effectiveness of clean clothing in reducing transdermal uptake of airborne SVOCs and conversely, that contaminated clothing could be a source of SVOC exposure via transdermal uptake and by acting as a vector for transporting those contaminants to other locations.
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Affiliation(s)
- Jacob Kvasnicka
- Department of Earth Sciences, University of Toronto, Toronto, Ontario, M5S 3B1, Canada
| | - Elaine A Cohen Hubal
- Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Durham, NC, 27711, USA
| | - Miriam L Diamond
- Department of Earth Sciences, University of Toronto, Toronto, Ontario, M5S 3B1, Canada.
- School of the Environment, University of Toronto, Toronto, Ontario, M5S 3E8, Canada.
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Horne J, Dunne N, Singh N, Safiuddin M, Esmaeili N, Erenler M, Ho I, Luk E. Building parameters linked with indoor transmission of SARS-CoV-2. ENVIRONMENTAL RESEARCH 2023; 238:117156. [PMID: 37717799 DOI: 10.1016/j.envres.2023.117156] [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: 03/04/2023] [Revised: 07/27/2023] [Accepted: 09/14/2023] [Indexed: 09/19/2023]
Abstract
The rapid spread of Coronavirus Disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has emphasized the importance of understanding and adapting to the indoor remediation of transmissible diseases to decrease the risk for future pandemic threats. While there were many precautions in place to hinder the spread of COVID-19, there has also been a substantial increase of new research on SARS-CoV-2 that can be utilized to further mitigate the transmission risk of this novel virus. This review paper aims to identify the building parameters of indoor spaces that could have considerable influence on the transmission of SARS-CoV-2. The following building parameters have been identified and analyzed, emphasizing their link with the indoor transmission of SARS-CoV-2: temperature and relative humidity, temperature differences between rooms, ventilation rate and access to natural ventilation, occupant density, surface type and finish, airflow direction and speed, air stability, indoor air pollution, central air conditioning systems, capacity of air handling system and HVAC filter efficiency, edge sealing of air filters, room layout and interior design, and compartmentalization of interior space. This paper also explains the interactions of SARS-CoV-2 with indoor environments and its persistence. Furthermore, the modifications of the key building parameters have been discussed for controlling the transmission of SARS-CoV-2 in indoor spaces. Understanding the information provided in this paper is crucial to develop effective health and safety measures that will aid in infection prevention.
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Affiliation(s)
- Jacqueline Horne
- Centre for Construction and Engineering Technologies, George Brown College, Casa Loma Campus, 160 Kendal Avenue, Toronto, ON M5R 1M3, Canada
| | - Nicholas Dunne
- Centre for Construction and Engineering Technologies, George Brown College, Casa Loma Campus, 160 Kendal Avenue, Toronto, ON M5R 1M3, Canada
| | - Nirmala Singh
- Centre for Construction and Engineering Technologies, George Brown College, Casa Loma Campus, 160 Kendal Avenue, Toronto, ON M5R 1M3, Canada
| | - Md Safiuddin
- Centre for Construction and Engineering Technologies, George Brown College, Casa Loma Campus, 160 Kendal Avenue, Toronto, ON M5R 1M3, Canada.
| | - Navid Esmaeili
- Centre for Construction and Engineering Technologies, George Brown College, Casa Loma Campus, 160 Kendal Avenue, Toronto, ON M5R 1M3, Canada
| | - Merve Erenler
- Centre for Construction and Engineering Technologies, George Brown College, Casa Loma Campus, 160 Kendal Avenue, Toronto, ON M5R 1M3, Canada
| | - Ian Ho
- Sysconverge Inc., 7030 Woodbine Avenue, Suite 500, Markham, ON L3R 6G2, Canada
| | - Edwin Luk
- Sysconverge Inc., 7030 Woodbine Avenue, Suite 500, Markham, ON L3R 6G2, Canada
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Liu S, Deng Z. Transmission and infection risk of COVID-19 when people coughing in an elevator. BUILDING AND ENVIRONMENT 2023; 238:110343. [PMID: 37143581 PMCID: PMC10122966 DOI: 10.1016/j.buildenv.2023.110343] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 04/02/2023] [Accepted: 04/20/2023] [Indexed: 05/06/2023]
Abstract
People in cities use elevators daily. With the COVID-19 pandemic, there are more worries about elevator safety, since elevators are often small and crowded. This study used a proven CFD model to see how the virus could spread in elevators. We simulated five people taking in an elevator for 2 min and analyzed the effect of different factors on the amount of virus that could be inhaled, such as the infected person's location, the standing positions of the persons, and the air flow rate. We found that the position of the infected person and the direction they stood greatly impacted virus transmission in the elevator. The use of mechanical ventilation with a flow rate of 30 ACH (air changes per hour) was effective in reducing the risk of infection. In situations where the air flow rate was 3 ACH, we found that the highest number of inhaled virus copies could range from 237 to 1186. However, with a flow rate of 30 ACH, the highest number was reduced to 153 to 509. The study also showed that wearing surgical masks decreased the highest number of inhaled virus copies to 74 to 155.
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Affiliation(s)
- Sumei Liu
- Tianjin Key Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Zhipeng Deng
- Department of Mechanical & Aerospace Engineering, Syracuse University, Syracuse, NY, 13244, United States
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Mao Y, Xie H, Liang J, He J, Ren J. Experimental study on the control effects of different strategies on particle transportation in a conference room: Mechanical ventilation, baffle, portable air cleaner, and desk air cleaner. ATMOSPHERIC POLLUTION RESEARCH 2023; 14:101716. [PMID: 36942301 PMCID: PMC9996463 DOI: 10.1016/j.apr.2023.101716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 03/08/2023] [Accepted: 03/08/2023] [Indexed: 06/18/2023]
Abstract
To control the spread and transmission of airborne particles (especially SARS-CoV-2 coronavirus, recently) in the indoor environment, many control strategies have been employed. Comparisons of these strategies enable a reasonable choice for indoor environment control and cost-effectiveness. In this study, a series of experiments were conducted in a full-scale chamber to simulate a conference room. The control effects of four different strategies (a ventilation system (320 m3/h) with and without a baffle, a specific type of portable air cleaner (400 m3/h) and a specific type of desk air cleaner (DAC, 160 m3/h)) on the transportation of particles of different sizes were studied. In addition, the effects of coupling the ventilation strategies with five forms of indoor airflow organization (side supply and side or ceiling return, ceiling supply and ceiling or side return, floor supply and ceiling return) were evaluated. The cumulative exposure level (CEL) and infection probability were selected as evaluation indexes. The experimental results showed that among the four strategies, the best particle control effect was achieved by the PAC. The reduction in CEL for particles in the overall size range was 22.1% under the ventilation system without a baffle, 34.3% under the ventilation system with a baffle, 46.4% with the PAC, and 10.1% with the DAC. The average infection probabilities under the four control strategies were 11.3-11.8%, 11.1-11.8%, 9.1-9.5%, and 18.2-19.7%, respectively. Among the five different forms of airflow organization, the floor supply and ceiling return mode exhibited the best potential ability to remove particles.
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Affiliation(s)
- Yanhui Mao
- School of Architecture and Transportation Engineering, Ningbo University of Technology, Ningbo, 315211, China
| | - Honglei Xie
- Architectural Design & Research Institute of Ningbo University, Ningbo, 315211, China
| | - Jianzhou Liang
- School of Architecture and Transportation Engineering, Ningbo University of Technology, Ningbo, 315211, China
| | - Junjie He
- School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, 300401, China
| | - Jianlin Ren
- School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, 300401, China
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Yuan Y, Li S, Chen T, Ren J. Effects of Ambient Temperature and Humidity on Natural Deposition Characteristics of Airborne Biomass Particles. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:1890. [PMID: 36767257 PMCID: PMC9914974 DOI: 10.3390/ijerph20031890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/14/2023] [Accepted: 01/17/2023] [Indexed: 06/18/2023]
Abstract
In the production process of biomass energy with crop straw as the raw material, the indoor dust environment created by smashed plant fiber can affect the health of workers and lead to the risk of fire and explosions. The physical properties of biomass vary with the ambient air conditions, resulting in different deposition processes for airborne biomass particles. In this study, the deposition of biomass particles in different environments in an experimental chamber was examined by independently controlling the internal temperature and relative humidity. The results show that in the ambient temperature range of 20~40 °C and at a relative humidity of 25~65%, the water absorption rates of the biomass particles were 15.4~24.7%. The deposition rates of the airborne biomass particles with different sizes were 0.9~2.9 h-1, which positively correlated with the particle sizes in the same ambient conditions. The increase in ambient temperature and relative humidity promoted the deposition of biomass particles with diameters over 0.5 μm. For the particles with diameters below 0.5 μm, the deposition rates were nonlinearly related to the ambient temperature and relative humidity and were greater at lower temperatures. The significance levels of the factors influencing the particle deposition were particle size > ambient temperature > ambient relative humidity. For the biomass particles below 0.5 μm, the influence of the relative humidity on the deposition was much weaker than that of the temperature.
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Tong Y, Yang H, Bao L, Guo B, Shi Y, Wang C. Analysis of Thermal Insulation Thickness for a Container House in the Yanqing Zone of the Beijing 2022 Olympic and Paralympic Winter Games. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:16417. [PMID: 36554297 PMCID: PMC9778341 DOI: 10.3390/ijerph192416417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 12/01/2022] [Accepted: 12/05/2022] [Indexed: 06/17/2023]
Abstract
A large number of temporary housings (THs) were used in the Yanqing zone of the Beijing 2022 Olympic and Paralympic Winter Games. Taking a kind of container house (CH) used in Yanqing zone as a model, the objective of this paper is to analyze the effect of insulation thickness on heating energy consumption and corresponding carbon emission. The effect of service life of THs on economic thickness was also discussed. The simulation model was developed using EnergyPlus and the heating energy consumption with different insulation materials was simulated based on the meteorological parameters of the top of Xiaohaituo Mountain (2177.5 m) and the Olympic/Paralympic Village (950 m) in Yanqing zone. In the simulation process, the thermal insulation performance of the CH was enhanced with reference to the requirements of GB/T 51350-2019 Technical Standard for Nearly Zero Energy Buildings (NZEB) on one hand. Additionally, the insulation performance was evaluated in terms of payback period and carbon emission. On the other hand, the economic thickness of different insulation materials (rock wool (RW), extruded polystyrene (XPS), polyurethane (PU)) and the high performance vacuum insulation panel (HVIP)) for different service lives of CH was studied. Results show that the U-values of the envelope meeting the NZEB standard can decrease approximately 21.4-32.8% of the heating energy consumption, compared with the original envelope. When the service life of CH is extended to 20 years, the carbon emission is reduced by 18.5% and 29.5%. The payback period of HVIP is longest, up to 31.4 a, and the results of economic thickness show that when the service life of the CH ranges from 1 year to 20 years, the economic thickness range of RW is 47-235 mm, XPS is 41-197 mm, PU is 33-149 mm and HVIP is 4-18 mm at the altitude of 2177.5 m. At the altitude of 950 m, the economic thickness range of RW is 28-158 mm, XPS is 26-131 mm, PU is 25-118 mm, and HVIP is 2-12 mm. From an economic point of view, the service life of a CH has a significant impact on the choice of insulation thickness.
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Affiliation(s)
- Yurou Tong
- School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
- Beijing Municipality Key Laboratory of Heating, Gas Supply, Ventilating, and Air Conditioning Engineering, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
| | - Hui Yang
- School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
- Beijing Municipality Key Laboratory of Heating, Gas Supply, Ventilating, and Air Conditioning Engineering, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
| | - Li Bao
- School of Humanities, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
| | - Baoxia Guo
- School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
- Beijing Municipality Key Laboratory of Heating, Gas Supply, Ventilating, and Air Conditioning Engineering, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
| | - Yanzhuo Shi
- School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
- Beijing Municipality Key Laboratory of Heating, Gas Supply, Ventilating, and Air Conditioning Engineering, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
| | - Congcong Wang
- School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
- Beijing Municipality Key Laboratory of Heating, Gas Supply, Ventilating, and Air Conditioning Engineering, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
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Mao Y, Wang S, Liang J, Mao S, Han Y, Zhang S. Stratum Ventilation: Enabling Simultaneous Energy Conservation and Air Purification in Subway Cars. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:14521. [PMID: 36361400 PMCID: PMC9659082 DOI: 10.3390/ijerph192114521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 10/30/2022] [Accepted: 11/03/2022] [Indexed: 06/16/2023]
Abstract
The supply of fresh air for underground rail transit systems is not as simple as opening windows, which is a conventional ventilation (CV) measure adopted in aboveground vehicles. This study aims to improve contaminant dilution and air purification in subway car ventilation systems and the safety of rail transit post-coronavirus disease pandemic era. We designed an air conditioning (AC) terminal system combined with stratum ventilation (SV) to enable energy consumption reduction for subway cars. We experimentally tested the effectiveness of a turbulence model to investigate ventilation in subway cars. Further, we compared the velocity fields of CV and SV in subway cars to understand the differences in their airflow organizations and contaminant removal efficiencies, along with the energy savings of four ventilation scenarios, based on the calculations carried out using computational fluid dynamics. At a ventilation flow rate of 7200 m3/h, the CO2 concentration and temperature in the breathing areas of seated passengers were better in the SV than in the CV at a rate of 8500 m3/h. Additionally, the energy-saving rate of SV with AC cooling was 14.05%. The study provides new ideas for reducing the energy consumption of rail transit and broadens indoor application scenarios of SV technology.
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Qin H, Yu Z, Li T, Liu X, Li L. Heating Control Strategy Based on Dynamic Programming for Building Energy Saving and Emission Reduction. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:14137. [PMID: 36361012 PMCID: PMC9653744 DOI: 10.3390/ijerph192114137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 10/24/2022] [Accepted: 10/27/2022] [Indexed: 06/16/2023]
Abstract
Finding the optimal balance between end-user's comfort, lifestyle preferences and the cost of the heating, ventilation and air conditioning (HVAC) system, which requires intelligent decision making and control. This paper proposes a heating control method for HVAC based on dynamic programming. The method first selects the most suitable modeling approach for the controlled building among three machine learning modeling techniques by means of statistical performance metrics, after which the control of the HVAC system is described as a constrained optimization problem, and the action of the controller is given by solving the optimization problem through dynamic programming. In this paper, the variable 'thermal energy storage in building' is introduced to solve the problem that dynamic programming is difficult to obtain the historical state of the building due to the requirement of no aftereffect, while the room temperature and the remaining start hours of the Primary Air Unit are selected to describe the system state through theoretical analysis and trial and error. The results of the TRNSYS/Python co-simulation show that the proposed method can maintain better indoor thermal environment with less energy consumption compared to carefully reviewed expert rules. Compared with expert rule set 'baseline-20 °C', which keeps the room temperature at the minimum comfort level, the proposed control algorithm can save energy and reduce emissions by 35.1% with acceptable comfort violation.
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Affiliation(s)
- Haosen Qin
- Tianjin Key Laboratory of Clean Energy and Pollutant Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 400301, China
| | - Zhen Yu
- Institute of Building Environment and Energy, China Academy of Building Research, Beijing 100013, China
| | - Tailu Li
- Tianjin Key Laboratory of Clean Energy and Pollutant Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 400301, China
| | - Xueliang Liu
- Institute of Building Environment and Energy, China Academy of Building Research, Beijing 100013, China
| | - Li Li
- Institute of Building Environment and Energy, China Academy of Building Research, Beijing 100013, China
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Ren J, Duan S, Guo L, Li H, Kong X. Effects of Return Air Inlets' Location on the Control of Fine Particle Transportation in a Simulated Hospital Ward. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:11185. [PMID: 36141451 PMCID: PMC9517334 DOI: 10.3390/ijerph191811185] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 08/29/2022] [Accepted: 09/03/2022] [Indexed: 06/16/2023]
Abstract
The COVID-19 pandemic has made significant impacts on public health, including human exposure to airborne pathogens. In healthcare facilities, the locations of return air vents in ventilation systems may have important effects on lowering airborne SARS-CoV-2 transmission. This study conducted experiments to examine the influence of different return air vents' heights (0.7 m, 1.2 m, and 1.6 m) on the particle removal effects in a simulated patient ward. Three different ventilation systems were examined: top celling air supply-side wall return (TAS), underfloor air supply-side wall return (UFAS) and side wall air supply-side wall return (SAS). CFD simulation was applied to further study the effects of return air inlets' heights (0.3 m, 0.7 m, 1.2 m, 1.6 m, and 2.0 m) and air exchange rates. The technique for order of preference by similarity to ideal solution (TOPSIS) analysis was used to calculate the comprehensive scores of 60 scenarios using a multi-criterion method to obtain the optimal return air inlets' heights. Results showed that for each additional 0.5 m distance in most working conditions, the inhalation fraction index of medical staff could be reduced by about 5-20%. However, under certain working conditions, even though the distances between the patients and medical personnel were different, the optimal heights of return air vents were constant. For TAS and UFAS, the optimal return air inlets' height was 1.2 m, while for SAS, the best working condition was 1.6 m air supply and 0.7 m air return. At the optimum return air heights, the particle decay rate per hour of SAS was 75% higher than that of TAS, and the rate of particle decay per hour of SAS was 21% higher than that of UFAS. The location of return air inlets could further affect the operating cost-effectiveness of ventilation systems: the highest operating cost-effectiveness was 8 times higher than the lowest one.
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Affiliation(s)
- Jianlin Ren
- School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, China
| | - Shasha Duan
- School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, China
| | - Leihong Guo
- Tianjin Jin’an Thermal Power Co., Ltd., Tianjin 300130, China
| | - Hongwan Li
- Department of Biosystems & Agricultural Engineering, College of Engineering, Michigan State University, East Lansing, MI 48824, USA
| | - Xiangfei Kong
- School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, China
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Zauli-Sajani S, Marchesi S, Boselli G, Broglia E, Angella A, Maestri E, Marmiroli N, Colacci A. Effectiveness of a Protocol to Reduce Children's Exposure to Particulate Matter and NO 2 in Schools during Alert Days. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:11019. [PMID: 36078735 PMCID: PMC9517784 DOI: 10.3390/ijerph191711019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/31/2022] [Accepted: 08/31/2022] [Indexed: 06/15/2023]
Abstract
Reducing children's exposure to air pollutants should be considered a primary goal, especially for the most vulnerable subjects. The goal of this study was to test the effectiveness of applying a protocol in the event of alert days, i.e., days with forecasted PM10 levels above the EU limit value (50 µg/m3). The test was conducted, before the onset of SARS-CoV-2 restrictions, in a classroom of a primary school in Parma (Italy)-a highly polluted area in Northern Italy. The protocol included indications for the frequency of opening windows and doors, as well as the activation of an air purifier. Teachers and students were asked to apply the protocol only in the event of alert days, while no indications were provided for non-alert days. A monitoring system measuring PM1, PM2.5, PM10, CO2, and NO2 was deployed in the classroom. Measurements of the same parameters were also performed outdoors near the school. The application of the protocol reduced the indoor/outdoor (I/O) ratio for all toxic pollutants. The reduction was also remarkable for PM10-the most critical air quality parameter in the study area (1.5 and 1.1 for non-alert and alert days, respectively). Indoor concentrations of PM10-especially during non-alert days-were often higher than outdoors, showing a major contribution from resuspension due to the movement of people and personal cloud. The protocol did not cause any increase in indoor CO2 levels. Our findings showed that the application of a ventilation protocol together with the contribution of an air purifier may represent an effective way to reduce children's exposure to air pollution during severe air pollution episodes. Considering the onset of COVID-19 and the airborne transmission of pathogens, this protocol now has more meaningful implications for children's welfare, and can be integrated with protocols designed as measures against the spread of SARS-CoV-2.
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Affiliation(s)
- Stefano Zauli-Sajani
- Regional Agency for Prevention Environment and Energy of Emilia-Romagna (Arpae), 40139 Bologna, Italy
| | - Stefano Marchesi
- Regional Agency for Prevention Environment and Energy of Emilia-Romagna (Arpae), 40139 Bologna, Italy
| | - Giuseppe Boselli
- Regional Agency for Prevention Environment and Energy of Emilia-Romagna (Arpae), 40139 Bologna, Italy
| | | | | | - Elena Maestri
- Consorzio Interuniversitario Nazionale per le Scienze Ambientali (CINSA), Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy
| | - Nelson Marmiroli
- Consorzio Interuniversitario Nazionale per le Scienze Ambientali (CINSA), Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy
| | - Annamaria Colacci
- Regional Agency for Prevention Environment and Energy of Emilia-Romagna (Arpae), 40139 Bologna, Italy
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Kvasnicka J, Cohen Hubal EA, Siegel JA, Scott JA, Diamond ML. Modeling Clothing as a Vector for Transporting Airborne Particles and Pathogens across Indoor Microenvironments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:5641-5652. [PMID: 35404579 PMCID: PMC9069698 DOI: 10.1021/acs.est.1c08342] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 03/19/2022] [Accepted: 03/21/2022] [Indexed: 06/14/2023]
Abstract
Evidence suggests that human exposure to airborne particles and associated contaminants, including respiratory pathogens, can persist beyond a single microenvironment. By accumulating such contaminants from air, clothing may function as a transport vector and source of "secondary exposure". To investigate this function, a novel microenvironmental exposure modeling framework (ABICAM) was developed. This framework was applied to a para-occupational exposure scenario involving the deposition of viable SARS-CoV-2 in respiratory particles (0.5-20 μm) from a primary source onto clothing in a nonhealthcare setting and subsequent resuspension and secondary exposure in a car and home. Variability was assessed through Monte Carlo simulations. The total volume of infectious particles on the occupant's clothing immediately after work was 4800 μm3 (5th-95th percentiles: 870-32 000 μm3). This value was 61% (5-95%: 17-300%) of the occupant's primary inhalation exposure in the workplace while unmasked. By arrival at the occupant's home after a car commute, relatively rapid viral inactivation on cotton clothing had reduced the infectious volume on clothing by 80% (5-95%: 26-99%). Secondary inhalation exposure (after work) was low in the absence of close proximity and physical contact with contaminated clothing. In comparison, the average primary inhalation exposure in the workplace was higher by about 2-3 orders of magnitude. It remains theoretically possible that resuspension and physical contact with contaminated clothing can occasionally transmit SARS-CoV-2 between humans.
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Affiliation(s)
- Jacob Kvasnicka
- Department
of Earth Sciences, University of Toronto, Toronto, Ontario M5S 3B1, Canada
| | - Elaine A. Cohen Hubal
- Center
for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Durham, North Carolina 27711, United States
| | - Jeffrey A. Siegel
- Department
of Civil and Mineral Engineering, University
of Toronto, Toronto, Ontario M5S 1A4, Canada
- Dalla
Lana School of Public Health, University
of Toronto, Toronto, Ontario M5T 3M7, Canada
| | - James A. Scott
- Dalla
Lana School of Public Health, University
of Toronto, Toronto, Ontario M5T 3M7, Canada
- Department
of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, University of Toronto, 1 King’s College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Miriam L. Diamond
- Department
of Earth Sciences, University of Toronto, Toronto, Ontario M5S 3B1, Canada
- Dalla
Lana School of Public Health, University
of Toronto, Toronto, Ontario M5T 3M7, Canada
- School of
the Environment, University of Toronto, Toronto, Ontario M5S 3E8, Canada
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Ren J, He J, Kong X, Li H. Robustness of ventilation systems in the control of walking-induced indoor fluctuations: Method development and case study. BUILDING SIMULATION 2022; 15:1645-1660. [PMID: 35194487 PMCID: PMC8854482 DOI: 10.1007/s12273-022-0888-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 01/04/2022] [Accepted: 01/24/2022] [Indexed: 05/11/2023]
Abstract
Walking-induced fluctuations have a significant influence on indoor airflow and pollutant dispersion. This study developed a method to quantify the robustness of ventilation systems in the control of walking-induced fluctuation control. Experiments were conducted in a full-scale chamber with four different kinds of ventilation systems: ceiling supply and side return (CS), ceiling supply and ceiling return (CC), side supply and ceiling return (SC), and side supply and side return (SS). The measured temperature, flow and pollutant field data was (1) denoised by FFT filtering or wavelet transform; (2) fitted by a Gaussian function; (3) feature-extracted for the range and time scale disturbance; and then (4) used to calculate the range scale and time scale robustness for different ventilation systems with dimensionless equations developed in this study. The selection processes for FFT filtering and wavelet transform, FFT filter cut-off frequency, wavelet function, and decomposition layers are also discussed, as well as the threshold for wavelet denoising, which can be adjusted accordingly if the walking frequency or sampling frequency differs from that in other studies. The results show that for the flow and pollutant fields, the use of a ventilation system can increase the range scale robustness by 19.7%-39.4% and 10.0%-38.8%, respectively; and the SS system was 7.0%-25.7% more robust than the other three ventilation systems. However, all four kinds of ventilation systems had a very limited effect in controlling the time scale disturbance.
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Affiliation(s)
- Jianlin Ren
- School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, 300401 China
| | - Junjie He
- School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, 300401 China
| | - Xiangfei Kong
- School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, 300401 China
| | - Hongwan Li
- Department of Environmental Engineering Sciences, University of Florida, Gainesville, USA
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