Indoor Air Quality during Lockdown: A Monitoring-based Simulation-assisted Study in London

The Covid-19 outbreak has resulted in new patterns of home occupancy, the implications of which for indoor air quality (IAQ) and energy use are not well-known. In this context, the present study investigates 8 flats in London to uncover if during a lockdown, (a) IAQ in the monitored flats deteriorated, (b) the patterns of window operation by occupants changed, and (c) more effective ventilation patterns could enhance IAQ without significant increases in heating energy demand. To this end, one-year's worth of monitored data on indoor and outdoor environment along with occupant use of windows has been used to analyse the impact of lockdown on IAQ. Moreover, using on-site CO2 data, monitored occupancy and operation of windows, the team has calibrated a thermal performance model of one of the flats to investigate the implications of alternative ventilation strategies. The results suggest that despite the extended occupancy during lockdown, occupants relied less on natural ventilation, which led to significantly higher CO2 and PM10 concentrations. However, simple natural ventilation patterns or use of mechanical ventilation with heat recovery proves to be very effective to maintain acceptable IAQ. © International Building Performance Simulation Association, 2022

Campus outdoor environment, learning engagement, and the mental health of college students during the COVID-19 pandemic: From the perspective of students in different grades.

Introduction: During COVID-19, the mental health of Chinese university students has been a pressing concern. But the internal mechanism of perceived campus outdoor environment and learning engagement affecting college students' mental health during the COVID-19 pandemic has not been fully discussed. Methods: The current study used cross-sectional data from 45 Chinese universities to explore the relationship among perceptions of campus outdoor environments, learning engagement, and college student mental health, and focused on differences among college students in different grades. Results: Our study revealed the mental health problems of Chinese college students during the COVID-19 pandemic were more severe. The mental health of postgraduates was generally poor, and their risk of depression was higher than that of undergraduates. More importantly, for postgraduates, the direct impact of the perceived campus outdoor environment on their mental health was stronger. For undergraduates, the indirect impact of learning engagement on the effect of the perceived campus outdoor environment on their mental health was stronger. Conclusion: The results of the study have implications for campus planners, landscape architects, and university planners to pay particular attention to the needs of postgraduates for campus outdoor environments, which is of great significance to improve the overall mental health of students during the COVID-19 pandemic.

Identification of source location in a single-sided building with natural ventilation: Case of interunit pollutant dispersion

A sudden outbreak of COVID-19 occurred in December 2019 and its rapid spread over the last two years caused a global pandemic. A special airborne transmission via aerosols called interunit dispersion is risky in a high-density urban environment, which needs more attention. In order to identify the source location of pollutants or viruses under the interunit transmission condition with natural ventilation, this study adopted the inverse Computational Fluid Dynamics (CFD) simulation with the adjoint probability method. The detailed process of the inverse modeling was presented. Also, the possible interunit transmission routes of the pollutants or viruses were analyzed. A three-story building model with single-sided openings was built. Six different combinations of fixed sensor locations were tested, and it was determined that setting sensors in the four corner regions of the building was the optimist strategy. A total of 25 cases with five different wind directions (0°, 45°, 90°, 135°, and 180°) were tested to verify the accuracy of the source location with inverse modeling. The results showed that 67%–78% of the rooms in the building can be identified with a limited number of pollutant sensors and all rooms can be identified with one additional sensor in the downstream room of the building under different wind direction. This research revealed that the inverse modeling method could be used to identify the pollutant source in the coupled indoor and outdoor environment. Further, this work can provide guidance for the pollutant monitor positions in the applications.

ASMBoT: An Intelligent Sanitizing Robot in the Coronavirus Outbreak

Technology plays a vital role in our lives to meet basic hygiene necessities. Currently, the whole world is facing an epidemic situation and the practice of using sanitizers is common nowadays. Sanitizers are used by people to sanitize their hands and bodies. It is also used for sanitizing objects that come into contact with the machine. While sanitizing a small area, people manage to sanitize via pumps, but it becomes difficult to sanitize the same area every day. One of the most severe sanitation concerns is a simple, economic and efficient method to adequately clean the indoor and outdoor environments. In particular, effective sanitization is required for people working in a clinical environment. Recently, some commonly used sanitizer techniques include electric sanitizer spray guns, electric sanitizer disinfectants, etc. However, these sanitizers are not automated, which means a person is required to roam personally with the device to every place to spray the disinfectant or sanitize an area. Therefore, a novel, cost-effective automatic sanitizing machine (ASM) named ASMBoT is designed that can dispense the sanitizer effectively by solving the aforementioned problems. © 2022 IEEE.

Visual Analysis Tool for a BLE Technology based Tracking Data

Several systems deal with human mobility. Most of them are for outdoor environments and use mobile phones to capture data. However, there is a growing interest of enterprises to consider indoor movement to take employees and client classes into account. Moreover, they usually want to assign semantics to the visited locations. We propose a visual exploration tool for analyzing the dynamics of individual movements in an indoor environment in this work. We present the use of suitable charts and animations to explore these complex data better. Finally, we argue that one could use our solution to monitor social distancing in indoor environments, which is a sensible thing during the current COVID-19 pandemic. Copyright © 2021 by SCITEPRESS – Science and Technology Publications, Lda. All rights reserved.

Transport Characteristics and Transmission Risk of Virus-Containing Droplets from Coughing in Outdoor Windy Environment.

Particle dispersions have been widely studied inside rooms, but few databases have examined the transmission risk of respiratory droplets outdoors. This study investigated the wind effect on the dispersion of coughed droplets and the influence of social distancing on the infection risk in different susceptible persons using computational fluid dynamics simulations. Infection risk was evaluated based on direct depositions and exposure fractions. The results indicated that a reverse and upward flow formed in front of an infected man, and it enhanced as the wind strengthened, which transported more medium particles higher and increased the deposition on both infected and susceptible persons. Small particles moved above the neck, and they rarely deposited on the body. Medium particles larger than 60 µm were more likely to deposit and could reach the head of a healthy person under stronger winds. The exposure fraction achieved peak values when numerous particles passed the breathing zone. Although longer social distancing could alleviate the particle deposition on the face and delay the most dangerous time, its effect on infection risk was ambiguous. The infection risk was larger for a shorter susceptible person because more particles were deposited on the face, and the exposure fraction contributed by particles above the neck was larger.

Air quality assessment in indoor and outdoor environments: A review

Air quality impacts both the environment and health conditions of people in living space. The air quality assessment in indoor and outdoor environments is essential to resolve the health impacts caused by environmental degradation. The present investigation is focused on the study of air quality assessment in three major areas including Vehicle Cabins, inside buildings and outdoor environments. The studies of air quality by scientists and researchers for the past 33 years have been reviewed and reported. As the air spreadable disease can blowout when people with positive infections cough, sneeze, spewing nasal and throat secretions into the air including COVID-19 transmitted through contact with respiratory droplets through the air, this comprehensive report on air quality characteristics will provide awareness for human safety and promote more research for the invention of comfort air quality in human living space.

Coughing Intensity and Wind Direction Effects on the Transmission of Respiratory Droplets: A Computation with Euler-Lagrange Method

Studies on droplet transmission are needed to understand the infection mechanism of SARS-CoV-2. This research investigated the effects of coughing intensity and wind direction on respiratory droplets transportation using the Euler-Lagrange method. The results revealed that both coughing intensity and wind conditions considerably influence the transmission of small and medium droplets but had little effect on large droplets. A stronger coughing intensity resulted in small and medium droplets traveling farther in a calm wind and spreading widely and rapidly in a windy environment. The droplets do not travel far in the absence of ambient wind, even with stronger coughing. Medium droplets spread in clusters, and small droplets drifted out of the domain in the band area in different wind conditions except for 60 degrees and 90 degrees wind directions, in which cases, the droplets were blown directly downstream. In 0 degrees wind direction, many droplets were deposited on the human body. The fast and upward movement of particles in 60 degrees and 90 degrees directions could cause infection risk with short exposure. In 180 degrees wind direction, droplets spread widely and traveled slowly because of the reverse flow downstream, prolonged exposure can result in a high risk of infection.

Reducing Anxiety with Nature and Gardening (RANG): Evaluating the Impacts of Gardening and Outdoor Activities on Anxiety among U.S. Adults during the COVID-19 Pandemic.

The COVID-19 pandemic impacted mental health. Growing research has identified the mental health benefits of nature contact, including gardening. We used a cross-sectional survey to investigate the association between gardening and other outdoor activities with anxiety among U.S. adults. The RANG (Reducing Anxiety with Nature and Gardening) survey was distributed online from June-September 2020 through social media (Twitter and Facebook) and a national Master Gardeners listserv. Survey questions captured demographics, COVID-19 experiences, gardening, outdoor activities, and anxiety using the Generalized Anxiety Disorder 7-item scale. Data were analyzed using chi-square, Fisher's exact, and Kruskal-Wallis tests, as well as logistic regression. Among participants, 46% reported anxiety symptoms. Participants who had gardened ≥ 15 years and those gardening > 8 h over two weeks had lower anxiety scores. Spending more time outdoors on weekdays also decreased anxiety scores. After adjusting for covariates, lower odds of anxiety were identified for 50-69 and 70-89-year-olds vs. 18-29-year-olds; males vs. females; and Texas vs. Maryland residents. These findings confirm increased anxiety during the COVID-19 pandemic and suggest that sustained gardening and other outdoor activities could help reduce anxiety.

Integrating IoT with Vedic Technology to Purify Atmosphere

Agnihotra/Homa therapy is a gift to humanity from the ancient Vedic technology of bioenergy, climate science, medicine, and agriculture. It is an urgent need to purify the atmosphere and strengthen the immune system through Vedic Science techniques. Covid-19 has become a major threat globally. Agnihotra can be a useful tool to combat coronavirus. Agnihotra process purifies the atmosphere through fire prepared in a copper pyramid tuned to the biorhythm of sunrise and sunset. Technology is now part of our lives and the Internet of Things takes a significant share in making it possible. So IoT and Agnihotra fire technology is applicable for the improvement of all aspects of the environment and thereby having a very positive impact on the thrive of living organisms. IoT-based sensors will become the weapon in measuring the presence of bacteria, microbes, viruses in the surrounding area. They can be used for both indoor and outdoor environments and offers monitoring at a lower cost than conventional methods, in theory making the process of monitoring possible in many more locations. We also proposed an IoT based model where data will be gathered from various sensors before and after Yajna. It is then transmitted and stored on a cloud sub-system, where it is maintained, managed, and backed up. Further automation of analytical model building is done through the process of machine learning and data visualizations, thus enabling users to enhance their immune system by using technology and Vedic knowledge of Agnihotra. © 2021 IEEE.

SARS-CoV-2 spillover into hospital outdoor environments.

Facing the ongoing coronavirus infectious disease-2019 (COVID-19) pandemic, many studies focus on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in indoor environment, on solid surface or in wastewater. It remains unclear whether SARS-CoV-2 can spill over into outdoor environments and impose transmission risks to surrounding people and communities. In this study, we investigated the presence of SARS-CoV-2 by measuring viral RNA in 118 samples from outdoor environment of three hospitals in Wuhan. We detected SARS-CoV-2 in soils (205-550 copies/g), aerosols (285-1,130 copies/m3) and wastewaters (255-18,744 copies/L) in locations close to hospital departments receiving COVID-19 patients or in wastewater treatment sectors. These findings revealed a significant viral spillover in hospital outdoor environments that was possibly caused by respiratory droplets from patients or aerosolized particles from wastewater containing SARS-CoV-2. In contrast, SARS-CoV-2 was not detected in other areas or on surfaces with regular implemented disinfection. Soils may behave as viral warehouse through deposition and serve as a secondary source spreading SARS-CoV-2 for a prolonged time. For the first time, our findings demonstrate that there are high-risk areas out of expectation in hospital outdoor environments to spread SARS-CoV-2, calling for sealing of wastewater treatment unit and complete sanitation to prevent COVID-19 transmission risks.

Airborne transmission of pathogen-laden expiratory droplets in open outdoor space.

Virus-laden droplets dispersion may induce transmissions of respiratory infectious diseases. Existing research mainly focuses on indoor droplet dispersion, but the mechanism of its dispersion and exposure in outdoor environment is unclear. By conducting CFD simulations, this paper investigates the evaporation and transport of solid-liquid droplets in an open outdoor environment. Droplet initial sizes (dp = 10 µm, 50 µm, 100 µm), background relative humidity (RH = 35%, 95%), background wind speed (Uref = 3 m/s, 0.2 m/s) and social distances between two people (D = 0.5 m, 1 m, 1.5 m, 3 m, 5 m) are investigated. Results show that thermal body plume is destroyed when the background wind speed is 3 m/s (Froude number Fr ~ 10). The inhalation fraction (IF) of susceptible person decreases exponentially when the social distance (D) increases from 0.5 m to 5 m. The exponential decay rate of inhalation fraction (b) ranges between 0.93 and 1.06 (IF=IF0e-b(D-0.5)) determined by the droplet initial diameter and relative humidity. Under weak background wind (Uref = 0.2 m/s, Fr ~ 0.01), the upward thermal body plume significantly influences droplet dispersion, which is similar with that in indoor space. Droplets in the initial sizes of 10 µm and 50 µm disperse upwards while most of 100 µm droplets fall down to the ground due to larger gravity force. Interestingly, the deposition fraction on susceptible person is ten times higher at Uref = 3 m/s than that at Uref = 0.2 m/s. Thus, a high outdoor wind speed does not necessarily lead to a smaller exposure risk if the susceptible person locating at the downwind region of the infected person, and people in outdoors are suggested to not only keep distance of greater than 1.5 m from each other but also stand with considerable angles from the prevailing wind direction.