Pub Date : 2023-12-01DOI: 10.1177/1420326X221110043
Dadi Zhang, P. Bluyssen
Airborne transmission has been confirmed as one of three principal ways of SARS-CoV-2 transmission. To reduce the transmission of SARS-CoV-2 indoors, understanding the distribution of respiratory droplets (or aerosols) present in human breath seems therefore important. To study whether the CO2 concentration can be used as a proxy for the number of exhaled particles present in an occupied space, the distribution of particles with different diameters (0.3, 0.5, 1.0, 2.5, 5.0 and 10 μm) and CO2 concentrations were monitored in a classroom setting with six healthy subjects. Additionally, numbers of particles with the same sizes were measured in the breath of the same six healthy subjects separately. Results showed that (1) on the contrary to CO2, the main source of indoor particles came from outdoor air, and not from occupants; (2) the impacts of ventilation regimes on indoor particle numbers were different to the impacts on CO2 concentrations; and (3) almost no significant relationship between the number of indoor particles and CO2 concentration was observed. Based on these results, this study could therefore not conclude that the CO2 concentration in a classroom can be used as a proxy for the number of exhaled particles by the occupants.
{"title":"Exploring the possibility of using CO2 as a proxy for exhaled particles to predict the risk of indoor exposure to pathogens","authors":"Dadi Zhang, P. Bluyssen","doi":"10.1177/1420326X221110043","DOIUrl":"https://doi.org/10.1177/1420326X221110043","url":null,"abstract":"Airborne transmission has been confirmed as one of three principal ways of SARS-CoV-2 transmission. To reduce the transmission of SARS-CoV-2 indoors, understanding the distribution of respiratory droplets (or aerosols) present in human breath seems therefore important. To study whether the CO2 concentration can be used as a proxy for the number of exhaled particles present in an occupied space, the distribution of particles with different diameters (0.3, 0.5, 1.0, 2.5, 5.0 and 10 μm) and CO2 concentrations were monitored in a classroom setting with six healthy subjects. Additionally, numbers of particles with the same sizes were measured in the breath of the same six healthy subjects separately. Results showed that (1) on the contrary to CO2, the main source of indoor particles came from outdoor air, and not from occupants; (2) the impacts of ventilation regimes on indoor particle numbers were different to the impacts on CO2 concentrations; and (3) almost no significant relationship between the number of indoor particles and CO2 concentration was observed. Based on these results, this study could therefore not conclude that the CO2 concentration in a classroom can be used as a proxy for the number of exhaled particles by the occupants.","PeriodicalId":13578,"journal":{"name":"Indoor and Built Environment","volume":"116 34","pages":"1958 - 1972"},"PeriodicalIF":3.6,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138609536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-30DOI: 10.1177/1420326x231219468
Kun Han, Yongfa Diao, Jiawei Zhuang, M. Chu
Duct bend is one of the important parts of ventilation and dust removal systems, and particles deposited in curved ducts can reduce system efficiency or cause erosion on the bend wall. To investigate whether particle deposition is affected by imposed swirl on fluid flow, this article combines the RSM turbulence model and the Discrete Phase Model (DPM) to predict the deposition efficiency of particles in the bend under high Reynolds number conditions. The results show that the imposed swirl flow modifies the secondary flow initially dominated by the pressure gradient caused by the curvature effect. With the gradual increase of the swirl number ( S n), the deposition efficiency of the particles gradually decreased. However, when the swirl number is low ( S n ≤ 0.17), particles with smaller Stokes numbers are more susceptible to the intensity of turbulence. The higher the turbulence intensity near the wall, the easier it is for low inertia particles ( St ≤ 0.456) to deposit. The higher swirl intensity dominates the centrifugal force, reduces the turbulent intensity in the central region of the duct, improves the stability of the airflow and makes it easier for particles with larger inertia ( St ≥ 0.811) to pass through the bend.
{"title":"The effects of imposed swirling flow on the transport and deposition of particulate pollutants in the 90° industrial duct bends: An Eulerian-Lagrangian approach","authors":"Kun Han, Yongfa Diao, Jiawei Zhuang, M. Chu","doi":"10.1177/1420326x231219468","DOIUrl":"https://doi.org/10.1177/1420326x231219468","url":null,"abstract":"Duct bend is one of the important parts of ventilation and dust removal systems, and particles deposited in curved ducts can reduce system efficiency or cause erosion on the bend wall. To investigate whether particle deposition is affected by imposed swirl on fluid flow, this article combines the RSM turbulence model and the Discrete Phase Model (DPM) to predict the deposition efficiency of particles in the bend under high Reynolds number conditions. The results show that the imposed swirl flow modifies the secondary flow initially dominated by the pressure gradient caused by the curvature effect. With the gradual increase of the swirl number ( S n), the deposition efficiency of the particles gradually decreased. However, when the swirl number is low ( S n ≤ 0.17), particles with smaller Stokes numbers are more susceptible to the intensity of turbulence. The higher the turbulence intensity near the wall, the easier it is for low inertia particles ( St ≤ 0.456) to deposit. The higher swirl intensity dominates the centrifugal force, reduces the turbulent intensity in the central region of the duct, improves the stability of the airflow and makes it easier for particles with larger inertia ( St ≥ 0.811) to pass through the bend.","PeriodicalId":13578,"journal":{"name":"Indoor and Built Environment","volume":"89 1","pages":""},"PeriodicalIF":3.6,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139207493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-27DOI: 10.1177/1420326x231218638
Xi Chen, Miaomiao Qin, Yahui Gao, Yang Liu, Liu Yang
Understanding the coupling effect of multiple factors on particle deposition above the near-wall heat source is vital for human health, manufacturing, treasure protection and so on. This study investigated the concentrations and decay rate loss coefficient of particles in an experimental chamber with different heat-source configurations. Thirty-nine cases were created by changing the surface temperature and the shape of the near-wall heat source as well as the angular velocity of the six-bladed fan. The results reveal that the temperature, relative humidity, air velocity and the shape of the near-wall heat sources all exhibit different degrees of influence on the particle deposition. Also, the impacts of these factors on particle deposition on the vertical wall above near-wall heat sources can be further influenced by the size and location of particles.
{"title":"The influence of near-wall heat sources with different configurations on particle deposition in a small-scale chamber","authors":"Xi Chen, Miaomiao Qin, Yahui Gao, Yang Liu, Liu Yang","doi":"10.1177/1420326x231218638","DOIUrl":"https://doi.org/10.1177/1420326x231218638","url":null,"abstract":"Understanding the coupling effect of multiple factors on particle deposition above the near-wall heat source is vital for human health, manufacturing, treasure protection and so on. This study investigated the concentrations and decay rate loss coefficient of particles in an experimental chamber with different heat-source configurations. Thirty-nine cases were created by changing the surface temperature and the shape of the near-wall heat source as well as the angular velocity of the six-bladed fan. The results reveal that the temperature, relative humidity, air velocity and the shape of the near-wall heat sources all exhibit different degrees of influence on the particle deposition. Also, the impacts of these factors on particle deposition on the vertical wall above near-wall heat sources can be further influenced by the size and location of particles.","PeriodicalId":13578,"journal":{"name":"Indoor and Built Environment","volume":"12 1","pages":""},"PeriodicalIF":3.6,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139230378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Polycyclic Aromatic Hydrocarbons (PAHs), a group of semi-volatile organic pollutants with 2–7 aromatic rings are emitted in association with particulates/gases from incomplete combustion. They are persistent and affect human health adversely. This is the first study wherein PM2.5 bound PAHs from 8 different indoor air pollution sources, namely dhoop (DH1, DH2), incense sticks (IS1, IS2), cigarette, mosquito coil and solid fuels ‘coal and wood’, that are widely used in South-Asian countries were studied. Their emission rates and concentration profiles were compared. Dhoop was studied for the first time and found to be emitting the highest quantity of total PAHs. FLA/(FLA + PYR) ratio rightly indicated ingredients like wood and grass as sources. However, other ratios indicated petrogenic/coal origin, while BaP/(BaP + CHR) and BaA/(BaA + CHR) ratios were not reported earlier. The highest Toxicity Equivalent Concentration and Mutagenic Equivalent Concentration were estimated for DH2 and the lowest for cigarette smoke. The maximum Inhalation Lifetime Cancer Risk equal to 1.85 × 10−05 (adults) was observed for DH2, exceeding the WHO guidelines. These inferences will help in optimizing the indoor sources’ combustion duration and formulating manmade indoor sources. They will assist in identifying high-risk indoor environments, causative sources and control mechanisms.
{"title":"PM2.5 bound polycyclic aromatic hydrocarbons in an Indian residential indoor air environment and their health risk","authors":"Sangita Ghatge Goel, Shashank Somwanshi, Sanjay Kashyap, Rajesh Gupta","doi":"10.1177/1420326x231219211","DOIUrl":"https://doi.org/10.1177/1420326x231219211","url":null,"abstract":"Polycyclic Aromatic Hydrocarbons (PAHs), a group of semi-volatile organic pollutants with 2–7 aromatic rings are emitted in association with particulates/gases from incomplete combustion. They are persistent and affect human health adversely. This is the first study wherein PM2.5 bound PAHs from 8 different indoor air pollution sources, namely dhoop (DH1, DH2), incense sticks (IS1, IS2), cigarette, mosquito coil and solid fuels ‘coal and wood’, that are widely used in South-Asian countries were studied. Their emission rates and concentration profiles were compared. Dhoop was studied for the first time and found to be emitting the highest quantity of total PAHs. FLA/(FLA + PYR) ratio rightly indicated ingredients like wood and grass as sources. However, other ratios indicated petrogenic/coal origin, while BaP/(BaP + CHR) and BaA/(BaA + CHR) ratios were not reported earlier. The highest Toxicity Equivalent Concentration and Mutagenic Equivalent Concentration were estimated for DH2 and the lowest for cigarette smoke. The maximum Inhalation Lifetime Cancer Risk equal to 1.85 × 10−05 (adults) was observed for DH2, exceeding the WHO guidelines. These inferences will help in optimizing the indoor sources’ combustion duration and formulating manmade indoor sources. They will assist in identifying high-risk indoor environments, causative sources and control mechanisms.","PeriodicalId":13578,"journal":{"name":"Indoor and Built Environment","volume":"1 1","pages":""},"PeriodicalIF":3.6,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139234051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The personalized environmental control system (PECS) meets the diverse comfort needs of occupants in an efficient way, amongst which, personalized heating systems have been extensively applied for heating in winter. Based on the differences in targeted body segments and application scenarios, the study of the heating performance and examining the applicability of different heating devices under various working conditions are necessary. In the present study, the heating effect of selected personalized heating devices including table heating pads, cushion heating pads and leg heating pads was investigated under different indoor temperatures (16°C, 18°C and 20°C). The results show that the cushion heating pads could produce the best heating effect in the environment at 16°C and 18°C. The average thermal comfort vote (TCV) was 0.00 and 1.08, respectively. While in the environment at 20°C, the leg heating pad (LH) was found to be the best with an average value of TCV to be 0.92. Personalized heating devices could directly enhance the thermal sensation and skin temperature of targeted body segments, such as the hands as well as legs, which are to be the most beneficial parts. The conclusions drawn above clarify the application scenarios of selected heating devices and will help to develop more energy-efficient heating schemes in winter.
{"title":"Differences in heating effects of three personalized heating devices under various indoor temperatures: Table heating pad, cushion heating pad and leg heating pad","authors":"Jia Chao, Shaoxuan Li, Zhicheng Zhang, Menghan Wang, Wenzhuo Hou","doi":"10.1177/1420326x231218365","DOIUrl":"https://doi.org/10.1177/1420326x231218365","url":null,"abstract":"The personalized environmental control system (PECS) meets the diverse comfort needs of occupants in an efficient way, amongst which, personalized heating systems have been extensively applied for heating in winter. Based on the differences in targeted body segments and application scenarios, the study of the heating performance and examining the applicability of different heating devices under various working conditions are necessary. In the present study, the heating effect of selected personalized heating devices including table heating pads, cushion heating pads and leg heating pads was investigated under different indoor temperatures (16°C, 18°C and 20°C). The results show that the cushion heating pads could produce the best heating effect in the environment at 16°C and 18°C. The average thermal comfort vote (TCV) was 0.00 and 1.08, respectively. While in the environment at 20°C, the leg heating pad (LH) was found to be the best with an average value of TCV to be 0.92. Personalized heating devices could directly enhance the thermal sensation and skin temperature of targeted body segments, such as the hands as well as legs, which are to be the most beneficial parts. The conclusions drawn above clarify the application scenarios of selected heating devices and will help to develop more energy-efficient heating schemes in winter.","PeriodicalId":13578,"journal":{"name":"Indoor and Built Environment","volume":"1 1","pages":""},"PeriodicalIF":3.6,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139238477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-20DOI: 10.1177/1420326x231217477
Zhe Liu, Bo-Hua Sun, Haihang Cui, Minghua Huang
The air distributor is the end component of the ventilation system, and its performance directly determines the comfortable and pleasant feeling of the residence. A perforated plate can be added to the air distributor to convert dynamic pressure into static pressure first and then distribute the air flow, which provides better self-adjustment compared with the embedded guide vane structure. However, the perforated plate can lead to a contradiction between head loss, noise and distribution uniformity. To reconcile this problem, a novel V-shape configuration of the perforated plate was put forward in this study. The internal flow and aeroacoustic properties of different types of perforated plates were systematically studied, and a full-scale test platform was built to verify the flow characteristics. The effects of hole size and installation position of the perforated plate on the uniform distribution of air flow were analyzed by the parametric analysis method. Then, the sound pressure level of the optimized perforated plate air distributor was further analyzed. The results show that, with the optimized perforated plate structure, the uniform flow performance was improved by about 30% and the overall sound pressure level was reduced by up to 12 dB.
空气分配器是通风系统的末端部件，其性能直接决定了住宅的舒适度和愉悦感。在空气分配器上加装穿孔板，可以先将动压转化为静压，然后再分配气流，与嵌入式导叶结构相比，具有更好的自调节能力。然而，穿孔板会导致水头损失、噪音和分布均匀性之间的矛盾。为了解决这一问题，本研究提出了一种新颖的 V 型穿孔板结构。系统研究了不同类型穿孔板的内部流动和气声特性，并搭建了一个全尺寸试验平台来验证其流动特性。通过参数分析方法，分析了穿孔板的孔径和安装位置对气流均匀分布的影响。然后，进一步分析了优化后的穿孔板空气分布器的声压级。结果表明，采用优化的穿孔板结构后，均匀气流性能提高了约 30%，整体声压级降低了 12 dB。
{"title":"Improvement of airflow uniformity and noise reduction with optimized V-shape configuration of perforated plate in the air distributor","authors":"Zhe Liu, Bo-Hua Sun, Haihang Cui, Minghua Huang","doi":"10.1177/1420326x231217477","DOIUrl":"https://doi.org/10.1177/1420326x231217477","url":null,"abstract":"The air distributor is the end component of the ventilation system, and its performance directly determines the comfortable and pleasant feeling of the residence. A perforated plate can be added to the air distributor to convert dynamic pressure into static pressure first and then distribute the air flow, which provides better self-adjustment compared with the embedded guide vane structure. However, the perforated plate can lead to a contradiction between head loss, noise and distribution uniformity. To reconcile this problem, a novel V-shape configuration of the perforated plate was put forward in this study. The internal flow and aeroacoustic properties of different types of perforated plates were systematically studied, and a full-scale test platform was built to verify the flow characteristics. The effects of hole size and installation position of the perforated plate on the uniform distribution of air flow were analyzed by the parametric analysis method. Then, the sound pressure level of the optimized perforated plate air distributor was further analyzed. The results show that, with the optimized perforated plate structure, the uniform flow performance was improved by about 30% and the overall sound pressure level was reduced by up to 12 dB.","PeriodicalId":13578,"journal":{"name":"Indoor and Built Environment","volume":"25 9","pages":""},"PeriodicalIF":3.6,"publicationDate":"2023-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139255657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-03DOI: 10.1177/1420326x231204513
Atthaillah Atthaillah, Rizki A. Mangkuto, Sarith Subramaniam, Brian Yuliarto
Daylighting is an essential factor in the design and operation of buildings, including schools. School buildings shall therefore be designed and constructed by considering climate variability that may affect daylighting performance. In some cases, such as in Indonesia, school classrooms are typically designed with symmetrical bilateral openings. However, recent literature suggests that such an opening typology may not necessarily lead to optimal daylight performance. This study investigated the potential of applying asymmetrical bilateral opening in tropical school classrooms by conducting validation with scale models and optimisation with climate-based daylight simulation. The window-to-wall ratio and external horizontal shading depth and elevation on opposing façades of the building model were considered input variables. Computational daylight simulation with Radiance (RAD) through the interface of Honeybee Plus (HB [+]) and optimisation using genetic algorithms (GA) were utilised to calculate annual daylight metrics (aUDI 250-750lx , aUDI 100-3000lx , sDA 300/50% and ASE 1000,250 ) and glare indices (DGP) under the climate of two Indonesian cities. Based on the optimisation, the recommended solutions are indeed in favour of asymmetrical opening configurations. These findings are crucial to improving the practice of designing tropical school classrooms with asymmetrical bilateral openings.
采光是包括学校在内的建筑物设计和运行的重要因素。因此，学校建筑的设计和建造应考虑到可能影响采光性能的气候变化。在某些情况下，例如在印度尼西亚，学校教室通常设计为对称的双边开口。然而，最近的文献表明，这种开放的类型可能不一定会导致最佳的日光性能。本研究通过比例模型验证和基于气候的日光模拟优化，探讨了在热带学校教室中应用不对称双边开放的潜力。窗墙比和建筑模型相对立面上的外部水平遮阳深度和标高被认为是输入变量。通过Honeybee Plus (HB[+])接口，利用Radiance (RAD)进行计算日光模拟，并使用遗传算法(GA)进行优化，计算印度尼西亚两个城市气候下的年度日光指标(aUDI 250-750lx、aUDI 100-3000lx、sDA 300/50%和ASE 1000,250)和眩光指数(DGP)。基于优化，推荐的解决方案确实有利于不对称的开口配置。这些发现对于改善热带学校教室不对称双边开口的设计实践至关重要。
{"title":"Daylighting design validation and optimisation of tropical school classrooms with asymmetrical bilateral opening typology","authors":"Atthaillah Atthaillah, Rizki A. Mangkuto, Sarith Subramaniam, Brian Yuliarto","doi":"10.1177/1420326x231204513","DOIUrl":"https://doi.org/10.1177/1420326x231204513","url":null,"abstract":"Daylighting is an essential factor in the design and operation of buildings, including schools. School buildings shall therefore be designed and constructed by considering climate variability that may affect daylighting performance. In some cases, such as in Indonesia, school classrooms are typically designed with symmetrical bilateral openings. However, recent literature suggests that such an opening typology may not necessarily lead to optimal daylight performance. This study investigated the potential of applying asymmetrical bilateral opening in tropical school classrooms by conducting validation with scale models and optimisation with climate-based daylight simulation. The window-to-wall ratio and external horizontal shading depth and elevation on opposing façades of the building model were considered input variables. Computational daylight simulation with Radiance (RAD) through the interface of Honeybee Plus (HB [+]) and optimisation using genetic algorithms (GA) were utilised to calculate annual daylight metrics (aUDI 250-750lx , aUDI 100-3000lx , sDA 300/50% and ASE 1000,250 ) and glare indices (DGP) under the climate of two Indonesian cities. Based on the optimisation, the recommended solutions are indeed in favour of asymmetrical opening configurations. These findings are crucial to improving the practice of designing tropical school classrooms with asymmetrical bilateral openings.","PeriodicalId":13578,"journal":{"name":"Indoor and Built Environment","volume":"5 9","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135873883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-30DOI: 10.1177/1420326x231205527
Tsz Wun Tsang, Ling Tim Wong, Kwok Wai Mui
Experimental studies can provide understanding, knowledge and real-case empirical evidence on the effects of building ventilation and environmental factors on airborne transmission in hospitals. Information obtained from existing studies gives insight into formulating engineering solutions and management practices to combat nosocomial airborne infections. A systemic review was conducted to summarize the experimental methods, research interests, useful results and limitations. With a steady but slow trend of increasing interest, experimental studies have been focusing mainly on the effects of ventilation systems, strategies and configurations on airborne transmission. The dispersion of bioaerosols under the combined effects of environmental factors, emission scenarios and human movement was investigated. Localized ventilation, air purifiers and disinfection technologies were also examined. The experimental techniques and some useful insights on optimal ventilation strategies and management practices were summarized and highlighted. Limitations of the empirical studies included sampling difficulties, limited scale and a number of testing scenarios, uncontrolled/unconsidered influencing factors and the media for experimentations. Using IoT-based sampling devices for experiments and real-time monitoring of bioaerosols or their surrogates, field surveys on a case-by-case basis in hospitals and interdisciplinary studies and collaborations could help overcome the research challenges and provide practical and effective solutions to minimize airborne transmission in hospitals.
{"title":"Experimental studies on airborne transmission in hospitals: A systematic review","authors":"Tsz Wun Tsang, Ling Tim Wong, Kwok Wai Mui","doi":"10.1177/1420326x231205527","DOIUrl":"https://doi.org/10.1177/1420326x231205527","url":null,"abstract":"Experimental studies can provide understanding, knowledge and real-case empirical evidence on the effects of building ventilation and environmental factors on airborne transmission in hospitals. Information obtained from existing studies gives insight into formulating engineering solutions and management practices to combat nosocomial airborne infections. A systemic review was conducted to summarize the experimental methods, research interests, useful results and limitations. With a steady but slow trend of increasing interest, experimental studies have been focusing mainly on the effects of ventilation systems, strategies and configurations on airborne transmission. The dispersion of bioaerosols under the combined effects of environmental factors, emission scenarios and human movement was investigated. Localized ventilation, air purifiers and disinfection technologies were also examined. The experimental techniques and some useful insights on optimal ventilation strategies and management practices were summarized and highlighted. Limitations of the empirical studies included sampling difficulties, limited scale and a number of testing scenarios, uncontrolled/unconsidered influencing factors and the media for experimentations. Using IoT-based sampling devices for experiments and real-time monitoring of bioaerosols or their surrogates, field surveys on a case-by-case basis in hospitals and interdisciplinary studies and collaborations could help overcome the research challenges and provide practical and effective solutions to minimize airborne transmission in hospitals.","PeriodicalId":13578,"journal":{"name":"Indoor and Built Environment","volume":"1 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136102373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-27DOI: 10.1177/1420326x231205139
Manoj Kumar Satheesan, Tsz-Wun Tsang, Kwok-Wai Mui, Ling-Tim Wong
Optimising ventilation strategy for an indoor environment necessitates systematically evaluating the influence of a diverse combination of physical and operational parameters in the design space. This study proposes a methodology that couples an evolutionary algorithm (genetic algorithm) with an evaluation mechanism (computational fluid dynamics) to determine the optimal ventilation strategy for an inpatient ward. The traditional approach would exhaustively simulate numerous scenarios to identify the optimal combination of parameters meeting the design objective. The proposed methodology would iteratively evaluate diverse design solutions with fewer CFD simulations than the traditional approach. The results of design space exploration suggest that design parameters, namely, location of the infected patient; air change rate; flow rate through local exhaust grille; and number, location and size of supply air diffuser and local air exhaust grille, are critical in minimising the risk of cross-infection caused through contact transmission in a ward.
{"title":"Optimal ventilation strategy for multi-bed hospital inpatient wards: CFD simulations using a genetic algorithm","authors":"Manoj Kumar Satheesan, Tsz-Wun Tsang, Kwok-Wai Mui, Ling-Tim Wong","doi":"10.1177/1420326x231205139","DOIUrl":"https://doi.org/10.1177/1420326x231205139","url":null,"abstract":"Optimising ventilation strategy for an indoor environment necessitates systematically evaluating the influence of a diverse combination of physical and operational parameters in the design space. This study proposes a methodology that couples an evolutionary algorithm (genetic algorithm) with an evaluation mechanism (computational fluid dynamics) to determine the optimal ventilation strategy for an inpatient ward. The traditional approach would exhaustively simulate numerous scenarios to identify the optimal combination of parameters meeting the design objective. The proposed methodology would iteratively evaluate diverse design solutions with fewer CFD simulations than the traditional approach. The results of design space exploration suggest that design parameters, namely, location of the infected patient; air change rate; flow rate through local exhaust grille; and number, location and size of supply air diffuser and local air exhaust grille, are critical in minimising the risk of cross-infection caused through contact transmission in a ward.","PeriodicalId":13578,"journal":{"name":"Indoor and Built Environment","volume":"8 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136317783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-27DOI: 10.1177/1420326x231205192
Mahmoud Fathy ElSharkawy
This study aimed to assess the level of IAQ (indoor air quality) through monitoring of several air pollutants inside selected homes in the Eastern Province of Saudi Arabia, and to study the most affecting factors on IAQ. Continuous 8-hour monitoring at each home during six months of 2019–2020 was conducted for six air pollutants inside and outside 200 homes, representing three main Saudi cities (Dammam, Al-Hofuf and Qatif). Measurements of six air pollutants were conducted in the kitchen, the living room and the bedroom inside each home and simultaneously outside these homes in their immediate vicinity. The highest mean levels of PM 10 (50.3 ± 20.0 µg/m 3 ), CO 2 (822.9 ± 195.1 ppm) and NO 2 (0.044 ± 0.009 ppm) were found in kitchens, while the highest mean level of CO (1.27 ± 0.25 ppm) was found in living rooms. As for total volatile organic compounds (TVOC) and SO 2 , their levels were nearly the same at three sites (0.21 ± 0.04 ppm and 0.018 ± 0.002 ppm, respectively). Levels of PM 10 exceeded their air quality guidelines (AQGs) in homes that are located near industrial and agricultural areas, while levels of other air pollutants were lower than their AQGs in all regions. The increase in concentrations of air pollutants outdoors was accompanied by an increase in concentrations indoors.
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