Tempo-spatial infection risk assessment of airborne virus via CO2 concentration field monitoring in built environment

Tang, Haida; Pan, Zhenyu; Li, Chunying

doi:10.1016/j.buildenv.2022.109067

Cited by 13 publications

(6 citation statements)

References 46 publications

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“…Monitoring the concentration of bioaerosols in the air in real-time or using surrogates to represent the relative levels of airborne microbes enables hospital operators to swiftly identify the risks of infection and provide fast and appropriate responses to mitigate airborne transmission. 142 Attempts to identify the associations between common air pollutants and airborne microbes need to be increased. More experiments should be done to determine the suitable indicators for microbial contaminants that can be monitored in real-time.…”

Section: Future Research Directionsmentioning

confidence: 99%

Experimental studies on airborne transmission in hospitals: A systematic review

Tsang,

Wong,

Mui

2023

Indoor and Built Environment

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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.

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Section: Future Research Directionsmentioning

confidence: 99%

Experimental studies on airborne transmission in hospitals: A systematic review

Tsang,

Wong,

Mui

2023

Indoor and Built Environment

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“…A fast-response and economical SF 6 sensor was recently seen in the literature but is not yet commercially available [25]. Nitrous oxide (N 2 O) is sometimes used as a tracer as it is physically similar to CO 2 , a respiratory contaminant that can be used as a proxy for infection risks [26]. However, N 2 O, commonly known as laughing gas and used for anesthetic and pain-reducing purposes, could cause short-term mental impairment and potentially neurological damage [27].…”

Section: Background Of Different Tracer Gasesmentioning

confidence: 99%

A Novel IoT-Enabled Wireless Sensor Grid for Spatial and Temporal Evaluation of Tracer Gas Dispersion

Tsang

Mui

Wong

et al. 2023

Sensors

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Current IoT applications in indoor air focus mainly on general monitoring. This study proposed a novel IoT application to evaluate airflow patterns and ventilation performance using tracer gas. The tracer gas is a surrogate for small-size particles and bioaerosols and is used in dispersion and ventilation studies. Prevalent commercial tracer-gas-measuring instruments, although highly accurate, are relatively expensive, have a long sampling cycle, and are limited in the number of sampling points. To enhance the spatial and temporal understanding of tracer gas dispersion under the influence of ventilation, a novel application of an IoT-enabled, wireless R134a sensing network using commercially available small sensors was proposed. The system has a detection range of 5–100 ppm and a sampling cycle of 10 s. Using Wi-Fi communication, the measurement data are transmitted to and stored in a cloud database for remote, real-time analysis. The novel system provides a quick response, detailed spatial and temporal profiles of the tracer gas level, and a comparable air change rate analysis. With multiple units deployed as a wireless sensing network, the system can be applied as an affordable alternative to traditional tracer gas systems to identify the dispersion pathway of the tracer gas and the general airflow direction.

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“…According to a systematic review of 19 articles in urban spaces, CO 2 is the primary reference for the spread of novel coronaviruses in buildings [ 22 ]. Studies have been conducted to visualize areas at high risk of COVID-19 infection using the CO 2 tracer gas method [ 23 – 27 ]. In South Africa, where TB is widely prevalent, CO 2 sensors have been installed in public buildings, and the application of Eq ( 1 ) to estimate the risk of TB transmission has confirmed that the chances of transmission in schools is relatively large [ 28 , 29 ].…”

Section: Introductionmentioning

confidence: 99%

Monitoring the ventilation of living spaces to assess the risk of airborne transmission of infection using a novel Pocket CO2 Logger to track carbon dioxide concentrations in Tokyo

Ishigaki,

Yokogawa

2024

PLoS ONE

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We employed carbon dioxide (CO2) concentration monitoring using mobile devices to identify location-specific risks for airborne infection transmission. We lent a newly developed, portable Pocket CO2 Logger to 10 participants, to be carried at all times, for an average of 8 days. The participants recorded their location at any given time as cinema, gym, hall, home, hospital, other indoors, other outgoings, pub, restaurant, university, store, transportation, or workplace. Generalized linear mixed model was used for statistical analysis, with the objective variable set to the logarithm of CO2 concentration. Analysis was performed by assigning participant identification as the random effect and location as the fixed effect. The data were collected per participant (seven males, four females), resulting in a total of 12,253 records. Statistical analysis identified three relatively poorly ventilated locations (median values > 1,000 ppm) that contributed significantly (p < 0.0001) to CO2 concentrations: homes (1,316 ppm), halls (1,173 ppm), and gyms (1005ppm). In contrast, two locations were identified to contribute significantly (p < 0.0001) to CO2 concentrations but had relatively low average values (<1,000 ppm): workplaces (705 ppm) and stores (620 ppm). The Pocket CO2 Logger can be used to visualize airborne infectious transmission risk by location to help guide recommendation regarding infectious disease policies, such as restrictions on human flow and ventilation measures and guidelines. In the future, large-scale surveys are expected to utilize the global positioning system, Wi-Fi, or Bluetooth of an individual’s smartphone to improve ease and accuracy.

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Tempo-spatial infection risk assessment of airborne virus via CO2 concentration field monitoring in built environment

Cited by 13 publications

References 46 publications

Experimental studies on airborne transmission in hospitals: A systematic review

Experimental studies on airborne transmission in hospitals: A systematic review

A Novel IoT-Enabled Wireless Sensor Grid for Spatial and Temporal Evaluation of Tracer Gas Dispersion

Monitoring the ventilation of living spaces to assess the risk of airborne transmission of infection using a novel Pocket CO2 Logger to track carbon dioxide concentrations in Tokyo

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