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Iwamura N, Tsutsumi K. Predicting the Airborne Transmission of Measles: Impact of Indoor Carbon Dioxide (CO2) Levels and Mitigation Strategies. Cureus 2024; 16:e64882. [PMID: 39156354 PMCID: PMC11330571 DOI: 10.7759/cureus.64882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/18/2024] [Indexed: 08/20/2024] Open
Abstract
BACKGROUND Measles is a highly contagious cause of febrile illness typically seen in young children. It is transmitted primarily through respiratory droplets and small-particle aerosols and can remain viable in the air. Despite the availability of an effective vaccine, measles remains a major global issue, particularly in regions with low vaccination rates. AIM This study aimed to quantify the airborne transmission risk of the measles virus in various indoor environments. METHODS Using indoor carbon dioxide (CO2) levels, we estimated the probability of airborne transmission and the basic reproduction number (Ro) in four hypothetical indoor scenarios, including restaurants, mass gathering events, homes, and business meetings, based on the modified Wells-Riley model. RESULTS The relationship between airborne transmission rates and indoor CO2 concentrations was visualized, with and without mask usage. Without masks, at an indoor CO2 concentration of 1,000 ppm, the airborne transmission rates were high in homes (100.0%) and business meetings (100.0%) and moderate in restaurants (45.6%) and live events (30.6%). By contrast, the Ro was high in audience-participatory live events (60.9%) and restaurants (13.2%), indicating a higher risk of cluster infections. DISCUSSION AND CONCLUSION In all indoor environmental scenarios, a positive linear relationship was found between the risk of airborne transmission and indoor CO2 levels. The risk of airborne transmission varied significantly across scenarios, which was influenced by various parameters, such as mask usage, quality of ventilation, conversation, and exposure duration. This model suggests that the risk of airborne transmission of measles can be easily predicted using a CO2 meter.
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Affiliation(s)
- Narumichi Iwamura
- Department of Nephrology, Yamaguchi Red Cross Hospital, Yamaguchi, JPN
| | - Kanako Tsutsumi
- Department of Nephrology, Yamaguchi Red Cross Hospital, Yamaguchi, JPN
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Zand MS, Spallina S, Ross A, Zandi K, Pawlowski A, Seplaki CL, Herington J, Corbett AM, Kaukeinen K, Holden-Wiltse J, Freedman EG, Alcantara L, Li D, Cameron A, Beaumont N, Dozier A, Dewhurst S, Foxe JJ. Ventilation during COVID-19 in a school for students with intellectual and developmental disabilities (IDD). PLoS One 2024; 19:e0291840. [PMID: 38568915 PMCID: PMC10990219 DOI: 10.1371/journal.pone.0291840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 02/21/2024] [Indexed: 04/05/2024] Open
Abstract
BACKGROUND This study examined the correlation of classroom ventilation (air exchanges per hour (ACH)) and exposure to CO2 ≥1,000 ppm with the incidence of SARS-CoV-2 over a 20-month period in a specialized school for students with intellectual and developmental disabilities (IDD). These students were at a higher risk of respiratory infection from SARS-CoV-2 due to challenges in tolerating mitigation measures (e.g. masking). One in-school measure proposed to help mitigate the risk of SARS-CoV-2 infection in schools is increased ventilation. METHODS We established a community-engaged research partnership between the University of Rochester and the Mary Cariola Center school for students with IDD. Ambient CO2 levels were measured in 100 school rooms, and air changes per hour (ACH) were calculated. The number of SARS-CoV-2 cases for each room was collected over 20 months. RESULTS 97% of rooms had an estimated ACH ≤4.0, with 7% having CO2 levels ≥2,000 ppm for up to 3 hours per school day. A statistically significant correlation was found between the time that a room had CO2 levels ≥1,000 ppm and SARS-CoV-2 PCR tests normalized to room occupancy, accounting for 43% of the variance. No statistically significant correlation was found for room ACH and per-room SARS-CoV-2 cases. Rooms with ventilation systems using MERV-13 filters had lower SARS-CoV-2-positive PCR counts. These findings led to ongoing efforts to upgrade the ventilation systems in this community-engaged research project. CONCLUSIONS There was a statistically significant correlation between the total time of room CO2 concentrations ≥1,000 and SARS-CoV-2 cases in an IDD school. Merv-13 filters appear to decrease the incidence of SARS-CoV-2 infection. This research partnership identified areas for improving in-school ventilation.
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Affiliation(s)
- Martin S. Zand
- Department of Medicine, Division of Nephrology, University of Rochester, Rochester, NY, United States of America
- Clinical and Translational Science Institute, University of Rochester, Rochester, NY, United States of America
- Department of Public Health Sciences, University of Rochester, Rochester, NY, United States of America
| | - Samantha Spallina
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, The Ernest J. Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States of America
| | - Alexis Ross
- The Mary Cariola Center, Rochester, NY, United States of America
| | - Karen Zandi
- The Mary Cariola Center, Rochester, NY, United States of America
| | - Anne Pawlowski
- The Mary Cariola Center, Rochester, NY, United States of America
| | - Christopher L. Seplaki
- Department of Public Health Sciences, University of Rochester, Rochester, NY, United States of America
- Department of Psychiatry, University of Rochester, Rochester, NY, United States of America
| | - Jonathan Herington
- Department of Health Humanities and Bioethics, University of Rochester, Rochester, NY, United States of America
| | - Anthony M. Corbett
- Clinical and Translational Science Institute, University of Rochester, Rochester, NY, United States of America
| | - Kimberly Kaukeinen
- Clinical and Translational Science Institute, University of Rochester, Rochester, NY, United States of America
| | - Jeanne Holden-Wiltse
- Clinical and Translational Science Institute, University of Rochester, Rochester, NY, United States of America
| | - Edward G. Freedman
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, The Ernest J. Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States of America
| | - Lisette Alcantara
- Clinical and Translational Science Institute, University of Rochester, Rochester, NY, United States of America
| | - Dongmei Li
- Clinical and Translational Science Institute, University of Rochester, Rochester, NY, United States of America
| | - Andrew Cameron
- Department of Pathology and Laboratory Medicine, University of Rochester, Rochester, NY, United States of America
| | - Nicole Beaumont
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, The Ernest J. Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States of America
| | - Ann Dozier
- Department of Public Health Sciences, University of Rochester, Rochester, NY, United States of America
| | - Stephen Dewhurst
- Department of Microbiology and Immunology, University of Rochester, Rochester, NY, United States of America
| | - John J. Foxe
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, The Ernest J. Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States of America
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Douglas IJ, Peh J, Mansfield KE, Trelfa A, Fowler T, Boulter M, Cleary P, Smith J, Edmunds WJ. A self-controlled case series study to measure the risk of SARS-CoV-2 infection associated with attendance at sporting and cultural events: the UK Events Research Programme events. BMC Med 2024; 22:100. [PMID: 38448944 PMCID: PMC10918946 DOI: 10.1186/s12916-024-03276-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 01/25/2024] [Indexed: 03/08/2024] Open
Abstract
BACKGROUND In 2021, whilst societies were emerging from major social restrictions during the SARS-CoV-2 pandemic, the UK government instigated an Events Research Programme to examine the risk of COVID-19 transmission from attendance at cultural events and explore ways to enable people to attend a range of events whilst minimising risk of transmission. We aimed to measure any impact on risk of COVID-19 transmission from attendance at events held at or close to commercially viable capacity using routinely collected data. METHODS Data were obtained on attendees at Phase 3 Events Research Programme events, for which some infection risk mitigation measures were in place (i.e. evidence of vaccination or a negative lateral flow test). Attendance data were linked with COVID-19 test result data from the UK Test and Trace system. Using a self-controlled case series design, we measured the within person incidence rate ratio for testing positive for COVID-19, comparing the rate in days 3 to 9 following event attendance (high risk period) with days 1 and 2 and 10-16 (baseline period). Rate ratios were adjusted for estimates of underlying regional COVID-19 prevalence to account for population level fluctuations in infection risk, and events were grouped into broadly similar types. RESULTS From attendance data available for 188,851 attendees, 3357 people tested positive for COVID-19 during the observation period. After accounting for total testing trends over the period, incidence rate ratios and 95% confidence intervals for positive tests were 1.16 (0.53-2.57) for indoor seated events, 1.12 (0.95-1.30) for mainly outdoor seated events, 0.65 (0.51-0.83) for mainly outdoor partially seated events, and 1.70 (1.52-1.89) for mainly outdoor unseated multi-day events. CONCLUSIONS For the majority of event types studied in the third phase of the UK Events Research Programme, we found no evidence of an increased risk of COVID-19 transmission associated with event attendance. However, we found a 70% increased risk of infection associated with attendance at mainly outdoor unseated multi-day events. We have also demonstrated a novel use for self-controlled case series methodology in monitoring infection risk associated with event attendance.
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Affiliation(s)
- Ian J Douglas
- London School of Hygiene and Tropical Medicine, London, UK
| | | | | | | | - Tom Fowler
- UK Health Security Agency, London, UK
- William Harvey Institute, Queen Mary University of London, London, UK
| | - Matthew Boulter
- UK Health Security Agency, London, UK
- Atlantic Medical Group, Penzance, UK
| | | | | | - W John Edmunds
- London School of Hygiene and Tropical Medicine, London, UK.
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Zand MS, Spallina S, Ross A, Zandi K, Pawlowski A, Seplaki CL, Herington J, Corbett AM, Kaukeinen K, Holden-Wiltse J, Freedman EG, Alcantara L, Li D, Cameron A, Beaumont N, Dozier A, Dewhurst S, Foxe JJ. Ventilation during COVID-19 in a school for students with intellectual and developmental disabilities (IDD). MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.09.08.23295268. [PMID: 37732178 PMCID: PMC10508805 DOI: 10.1101/2023.09.08.23295268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Background This study examined the correlation of classroom ventilation (air exchanges per hour (ACH)) and exposure to CO2 ≥1,000 ppm with the incidence of SARS-CoV-2 over a 20-month period in a specialized school for students with intellectual and developmental disabilities (IDD). These students were at a higher risk of respiratory infection from SARS-CoV-2 due to challenges in tolerating mitigation measures (e.g. masking). One in-school measure proposed to help mitigate the risk of SARS-CoV-2 infection in schools is increased ventilation. Methods We established a community-engaged research partnership between the University of Rochester and the Mary Cariola Center school for students with IDD. Ambient CO2 levels were measured in 100 school rooms, and air changes per hour (ACH) were calculated. The number of SARS-CoV-2 cases for each room was collected over 20 months. Results 97% of rooms had an estimated ACH ≤4.0, with 7% having CO2 levels ≥2,000 ppm for up to 3 hours per school day. A statistically significant correlation was found between the time that a room had CO2 levels ≥1,000 ppm and SARS-CoV-2 PCR tests normalized to room occupancy, accounting for 43% of the variance. No statistically significant correlation was found for room ACH and per-room SARS-CoV-2 cases. Rooms with ventilation systems using MERV-13 filters had lower SARS-CoV-2-positive PCR counts. These findings led to ongoing efforts to upgrade the ventilation systems in this community-engaged research project. Conclusions There was a statistically significant correlation between the total time of room CO2 concentrations ≥1,000 and SARS-CoV-2 cases in an IDD school. Merv-13 filters appear to decrease the incidence of SARS-CoV-2 infection. This research partnership identified areas for improving in-school ventilation.
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Affiliation(s)
- Martin S. Zand
- Department of Medicine, Division of Nephrology, University of Rochester, Rochester, NY, USA
- Clinical and Translational Science Institute, University of Rochester, Rochester, NY, USA
- Department of Public Health Sciences, University of Rochester, Rochester, NY, USA
| | - Samantha Spallina
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, The Ernest J. Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Alexis Ross
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, The Ernest J. Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | | | | | - Christopher L. Seplaki
- Department of Public Health Sciences, University of Rochester, Rochester, NY, USA
- Department of Psychiatry, University of Rochester, Rochester, NY, USA
| | - Jonathan Herington
- Department of Health Humanities and Bioethics, University of Rochester, Rochester, NY, USA
| | - Anthony M. Corbett
- Clinical and Translational Science Institute, University of Rochester, Rochester, NY, USA
| | - Kimberly Kaukeinen
- Clinical and Translational Science Institute, University of Rochester, Rochester, NY, USA
| | - Jeanne Holden-Wiltse
- Clinical and Translational Science Institute, University of Rochester, Rochester, NY, USA
| | - Edward G. Freedman
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, The Ernest J. Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Lisette Alcantara
- Clinical and Translational Science Institute, University of Rochester, Rochester, NY, USA
| | - Dongmei Li
- Clinical and Translational Science Institute, University of Rochester, Rochester, NY, USA
| | - Andrew Cameron
- Department of Pathology and Laboratory Medicine, University of Rochester, Rochester, NY, USA
| | - Nicole Beaumont
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, The Ernest J. Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Ann Dozier
- Department of Public Health Sciences, University of Rochester, Rochester, NY, USA
| | - Stephen Dewhurst
- Department of Microbiology and Immunology, University of Rochester, Rochester, NY, USA
| | - John J. Foxe
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, The Ernest J. Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
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Iwamura N, Tsutsumi K. SARS-CoV-2 airborne infection probability estimated by using indoor carbon dioxide. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023:10.1007/s11356-023-27944-9. [PMID: 37286835 DOI: 10.1007/s11356-023-27944-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 05/23/2023] [Indexed: 06/09/2023]
Abstract
Airborne transmission is one of the main routes of SARS-CoV-2 spread. It is important to determine the circumstances under which the risk of airborne transmission is increased as well as the effective strategy to reduce such risk. This study aimed to develop a modified version of the Wells-Riley model with indoor CO2 to estimate the probability of airborne transmission of SARS-CoV-2 Omicron strains with a CO2 monitor and to evaluate the validity of this model in actual clinical practices. We used the model in three suspected cases of airborne transmission presented to our hospital to confirm its validity. Next, we estimated the required indoor CO2 concentration at which R0 does not exceed 1 based on the model. The estimated R0 (R0, basic reproduction number) based on the model in each case were 3.19 in three out of five infected patients in an outpatient room, 2.00 in two out of three infected patients in the ward, and 0.191 in none of the five infected patients in another outpatient room. This indicated that our model can estimate R0 with an acceptable accuracy. In a typical outpatient setting, the required indoor CO2 concentration at which R0 does not exceed 1 is below 620 ppm with no mask, 1000 ppm with a surgical mask and 16000 ppm with an N95 mask. In a typical inpatient setting, on the other hand, the required indoor CO2 concentration is below 540 ppm with no mask, 770 ppm with a surgical mask, and 8200 ppm with an N95 mask. These findings facilitate the establishment of a strategy for preventing airborne transmission in hospitals. This study is unique in that it suggests the development of an airborne transmission model with indoor CO2 and application of the model to actual clinical practice. Organizations and individuals can efficiently recognize the risk of SARS-CoV-2 airborne transmission in a room and thus take preventive measures such as maintaining good ventilation, wearing masks, or shortening the exposure time to an infected individual by simply using a CO2 monitor.
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Affiliation(s)
- Narumichi Iwamura
- Sasebo Chuo Hospital, 15, Yamato-Cho, Sasebo-Shi, Nagasaki, 857-1165, Japan.
| | - Kanako Tsutsumi
- Sasebo Chuo Hospital, 15, Yamato-Cho, Sasebo-Shi, Nagasaki, 857-1165, Japan
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Malki-Epshtein L, Adzic F, Roberts BM, Hathway EA, Iddon C, Mustafa M, Cook M. Measurement and rapid assessment of indoor air quality at mass gathering events to assess ventilation performance and reduce aerosol transmission of SARS-CoV-2. BUILDING SERVICES ENGINEERING RESEARCH & TECHNOLOGY : BSER & T 2023; 44:113-133. [PMID: 38603254 PMCID: PMC9760526 DOI: 10.1177/01436244221137995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/13/2024]
Abstract
To assess risk factors for COVID-19 transmission and address the closure of mass gathering events since March 2020, the UK Government ran the Events Research Programme (ERP), following which it reopened live events in sports, music, and culture in July 2021. We report the rapid post-occupancy evaluation of Indoor Air Quality (IAQ) and associated long-range airborne transmission risk conducted in the Environmental Study of the ERP. Ten large venues around the UK were monitored with CO2 sensors at a high spatial and temporal resolution during 90 events. An IAQ Index based on CO2 concentration was developed, and all monitored spaces were classified in bands from A to G based on their average and maximum CO2 concentrations from all events. High resolution monitoring and the IAQ Index depicted the overall state of ventilation at live events, and allowed identification of issues with ventilation effectiveness and distribution, and of spaces with poor ventilation and the settings in which long-range airborne transmission risk may be increased. In numerous settings, CO2 concentrations were found to follow patterns relating to event management and specific occupancy of spaces around the venues. Good ventilation was observed in 90% of spaces monitored for given occupancies. Practical applications: High-resolution monitoring of indoor CO2 concentrations is necessary to detect the spatial variation of indoor air quality (IAQ) in large mass gathering event venues. The paper summarises COVID-19 ventilation guidance for buildings and defines a methodology for measurement and rapid assessment of IAQ during occupancy at live events that can be implemented by venue managers. Comparisons of the CO2 concentrations measured during the events identified the spaces at high risk of long-range transmission of airborne pathogens. Building operators should be mindful of the ventilation strategies used relative to the total occupancy in different spaces and the occupant's activities.
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Affiliation(s)
- Liora Malki-Epshtein
- Department of Civil, Environmental and Geomatic Engineering, University College London, London, UK
| | - Filipa Adzic
- Department of Civil, Environmental and Geomatic Engineering, University College London, London, UK
| | - Ben M Roberts
- Building Energy Research Group, Loughborough University, Loughborough, UK
| | | | | | | | - Malcolm Cook
- Building Energy Research Group, Loughborough University, Loughborough, UK
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Cheshmehzangi A, Su Z, Jin R, Dawodu A, Sedrez M, Pourroostaei Ardakani S, Zou T. Space and social distancing in managing and preventing COVID-19 community spread: An overview. Heliyon 2023; 9:e13879. [PMID: 36845035 PMCID: PMC9940482 DOI: 10.1016/j.heliyon.2023.e13879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 02/12/2023] [Accepted: 02/14/2023] [Indexed: 02/22/2023] Open
Abstract
The spread of COVID-19 at a large scale and at a rapid pace indicates the lack of social distancing measures at multiple levels. The individuals are not to be blamed, nor should we assume the early measures were ineffective or not implemented. It is all down to the multiplicity of transmission factors that made the situation more complicated than initially anticipated. Therefore, in facing the COVID-19 pandemic, this overview paper discusses the importance of space in social distancing measures. The methods used to investigate this study are literature review and case study. Many scholarly works have already provided us with evidence-based models that suggest the influential role of social distancing measures in preventing COVID-19 community spread. To further elaborate on this important topic, the aim here is to look at the role of space not only at the individual level but at larger scales of communities, cities, regions, etc. The analysis helps better management of cities during the pandemics such as COVID-19. By reflecting on some of the ongoing research on social distancing, the study concludes with the role of space at multiple scales and how it is central to the practice of social distancing. We need to be more reflective and responsive to achieve earlier control and containment of the disease and the outbreak at the macro level.
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Affiliation(s)
- Ali Cheshmehzangi
- Department of Architecture and Built Environment, University of Nottingham, Ningbo Campus, 199 Taikang East Road, University Park, Ningbo, 315100, China
- Network for Education and Research on Peace and Sustainability (NERPS), Hiroshima University, 1-3-1, Kagamiyama Higashi-Hiroshima City, Hiroshima, 739-8530, Japan
| | - Zhaohui Su
- Center on Smart and Connected Health Technologies, Mays Cancer Center, School of Nursing, UT Health San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229, USA
| | - Ruoyu Jin
- School of Built Environment and Architecture, Division of Construction, Property and Surveying, London South Bank University, 103 Borough Road, London, SE1 0AA, UK
| | - Ayotunde Dawodu
- School of Architecture and Built Environment, University of Greenwich, Old Royal Naval College, Park Row, London SE10 9LS, UK
| | - Maycon Sedrez
- School of Architecture and Built Environment, Deakin University, 221 Burwood Hwy, Burwood, VIC 3125, Australia
| | | | - Tong Zou
- Department of Architecture and Built Environment, University of Nottingham, Ningbo Campus, 199 Taikang East Road, University Park, Ningbo, 315100, China
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Zhou Q, Zhong H, Li L, Wang Z. AlphaMobileSensing: A virtual testbed for mobile environmental monitoring. BUILDING SIMULATION 2023; 16:1-14. [PMID: 37359829 PMCID: PMC9971688 DOI: 10.1007/s12273-023-1001-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/16/2023] [Accepted: 02/06/2023] [Indexed: 06/28/2023]
Abstract
Environmental monitoring plays a critical role in creating and maintaining a comfortable, productive, and healthy environment. Built upon the advancements of robotics and data processing, mobile sensing demonstrates its potential to address problems regarding cost, deployment, and resolution that stationary monitoring encounters, which therefore has attracted increasing research attentions recently. To facilitate mobile sensing, two key algorithms are needed: the field reconstruction algorithm and the route planning algorithm. The field reconstruction algorithm is to reconstruct the entire environment field from spatially- and temporally-discrete measurements collected by the mobile sensors. The route planning algorithm is to instruct the mobile sensors where the mobile sensor needs to move to for the next measurements. The performance of mobile sensors highly depends on these two algorithms. However, developing and testing those algorithms in the real world is expensive, challenging, and time-consuming. To address these issues, we proposed and implemented an open-source virtual testbed, AlphaMobileSensing, that can be used to develop, test, and benchmark mobile sensing algorithms. AlphaMobileSensing aims to help users more easily develop and test the field reconstruction and route planning algorithms for mobile sensing solutions, without worrying about hardware fault, test accidents (such as collision during the test), etc. The separation of concerns can significantly reduce the cost of developing software solutions for mobile sensing. For versatility and flexibility, AlphaMobileSensing was wrapped up using the standardized interface of OpenAI Gym, and it also provides an interface for loading physical fields that were generated by numerical simulations as virtual test sites to perform mobile sensing and retrieving monitoring data. We demonstrated applications of the virtual testbed by implementing and testing algorithms for physical field reconstruction in both static and dynamic indoor thermal environments. AlphaMobileSensing provides a novel and flexible platform to develop, test, and benchmark mobile sensing algorithms more easily, conveniently, and efficiently. AlphaMobileSensing is open sourced at https://github.com/kishuqizhou/AlphaMobileSensing. Electronic Supplementary Material ESM the Appendix is available in the online version of this article at 10.1007/s12273-023-1001-9.
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Affiliation(s)
- Qi Zhou
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Haoran Zhong
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Linyan Li
- School of Data Science, City University of Hong Kong, Hong Kong, China
| | - Zhe Wang
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
- HKUST Shenzhen-Hong Kong Collaborative Innovation Research Institute, Futian, Shenzhen, China
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Li Y, Fan Y, Zhi C, Ye W, Zhang X. Multi-objective optimization of mechanical ventilation with the aid of purifiers in two scenarios: Regular operation and mitigating the spread of respiratory infectious diseases. BUILDING SIMULATION 2023; 16:795-811. [PMID: 37128474 PMCID: PMC10126557 DOI: 10.1007/s12273-023-0999-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 01/12/2023] [Accepted: 02/02/2023] [Indexed: 05/03/2023]
Abstract
COVID-19 and its impact on society have raised concerns about scaling up mechanical ventilation (MV) systems and the energy consequences. This paper attempted to combine MV and portable air cleaners (PACs) to achieve acceptable indoor air quality (IAQ) and energy reduction in two scenarios: regular operation and mitigating the spread of respiratory infectious diseases (RIDs). We proposed a multi-objective optimization method that combined the NSGA-II and TOPSIS techniques to determine the total equivalent ventilation rate of the MV-PAC system in both scenarios. The concentrations of PM2.5 and CO2 were primary indicators for IAQ. The modified Wells-Riley equation was adopted to predict RID transmissions. An open office with an MV-PAC system was used to demonstrate the method's applicability. Meanwhile, a field study was conducted to validate the method and evaluate occupants' perceptions of the MV-PAC system. Results showed that optimal solutions of the combined system can be obtained based on various IAQ requirements, seasons, outdoor conditions, etc. For regular operation, PACs were generally prioritized to maintain IAQ while reducing energy consumption even when outdoor PM2.5 concentration was high. MV can remain constant or be reduced at low occupancies. In RID scenarios, it is possible to mitigate transmissions when the quanta were < 48 h-1. No significant difference was found in the subjective perception of the MV and PACs. Moreover, the effects of infiltration on the optimal solution can be substantial. Nonetheless, our results suggested that an MV-PAC system can replace the MV system for offices for daily use and RID mitigation. Electronic Supplementary Material ESM The Appendix is available in the online version of this article at 10.1007/s12273-023-0999-z.
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Affiliation(s)
- Yiqun Li
- School of Mechanical Engineering, Tongji University, Shanghai, 201804 China
| | - Yujie Fan
- Department of Building Science, Tsinghua University, Beijing, 100084 China
| | - Chengqiang Zhi
- School of Mechanical Engineering, Tongji University, Shanghai, 201804 China
| | - Wei Ye
- School of Mechanical Engineering, Tongji University, Shanghai, 201804 China
- Key Laboratory of Engineering Structure Performance Evolution and Control, Ministry of Education, Tongji University, Shanghai, 200092 China
| | - Xu Zhang
- School of Mechanical Engineering, Tongji University, Shanghai, 201804 China
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