Post-Occupancy study of indoor air quality in university laboratories during the pandemic

This post-occupancy study aims to assess the indoor air quality (IAQ) and ventilation performance in workshops and laboratories of a UK university during the COVID-19 pandemic. Supply airflow rates and CO2 were monitored as a proxy for evaluating ventilation performance. Additionally, particulate matter (PM10) was monitored to address the occupant's concerns about dust. Monitoring showed that maximum CO2 values recorded are mostly below 1000 ppm, with weekly averages below 520 ppm. This was expected as the supply airflow rates were significantly larger than recommended 10 l/s per occupant. Despite the large flow rates, PM10 levels in some laboratories were above the threshold value of 50 [μg/m3] supporting the poor IAQ claims of the occupants. The study indicated the room air re-circulation and indoor activities as the likely reasons for the elevated PM10 levels and some practical operational solutions were suggested for IAQ concerns. © 2022 17th International Conference on Indoor Air Quality and Climate, INDOOR AIR 2022. All rights reserved.

Comparison of indoor air quality and thermal comfort standards and variations in exceedance for school buildings

Addressing indoor air quality (IAQ) and thermal comfort issues in school buildings is challenging but relevant. Firstly, their primary occupants are more vulnerable than adults. Secondly, school buildings are often inadequate being too old or designed to prioritise energy-efficiency targets. Thirdly, occupants have often little control over the indoor environmental quality (IEQ). Lastly, the SARS-CoV-2 pandemic highlighted the complexity and vulnerability of existing decision-making processes in relation to making timely and well-informed decisions about IEQ threats. Standards and guidelines vary over time and among similar countries despite targeting similar occupants, evaluate IAQ and thermal comfort independently, and do not include any specific adaptations to children. Thus, the aim of this research is to compare different available standards to evaluate IAQ and thermal comfort in school buildings. By analysing with different standards (EN16798, BB101, and ASHRAE 55 and 62.1) the data collected in schools in northern Italy, this research evaluated the consequences of different limits and approaches, and proposed improvements. The conclusions are that (i) thresholds and methods inconsistency within the same standard should be avoided;(ii) upper- and lower-bounded operative temperature scales are the most appropriate means to design and verify thermal comfort in classrooms;(iii) IAQ metrics that give an upper limit per a certain amount of consecutive time might prevent the build-up of indoor pollutants, even with high emissions from the building fabric;(iv) no standard proposes a combined IAQ and thermal comfort analysis which could enable more informed trade-off decisions considering IAQ, thermal comfort, and energy targets. © 2023 The Authors

Evaluation of ventilation in Australian school classrooms using long-term indoor CO2 concentration measurements

School classrooms are often reported as having insufficient ventilation with elevated indoor CO2 concentrations. This paper reports on pre-pandemic field measurements of CO2 concentration levels conducted for an academic year in 10 classrooms from four primary and a secondary school in Victoria, Australia. Measured CO2 concentrations across the 10 classrooms which were operated with a mix of intermittent natural ventilation and air-conditioning for cooling or heating, on average ranged between 657 ppm and 2235 ppm during school hours with median over 1000 ppm in 70% of classrooms. All 10 classrooms in the study exceeded the Australian recommended limit of 850 ppm. Using average peak CO2 concentrations from year-long measurements, estimated ventilation rate (VR) of 4.08 Ls-1 per person show under-performing classrooms where 60% had VRs 35–40% lower than the 10-12 Ls−1 per person Australian recommendation. Estimated VR range of 1.24–2.07 Ls-1 per person using peak maximum CO2 levels were 19–30% lower than ASHRAE recommendation of 6.7 Ls-1 per person. These VRs translate to a range of air change rates on average between 0.52 and 0.88 h−1 ± 0.26–0.59, well below the 6.0 h−1 recommendation for good indoor ventilation by the World Health Organisation in the context of COVID-19 pandemic. Characterisation of ventilation and indoor air quality in current Australian classroom stock is critical for the improvement of classroom design, induction on room operating practices, understanding of the school community on the relevance of building ventilation on school performance and health, and development of appropriate ventilation and indoor air quality guidelines for schools. © 2023 The Authors

Toxic schools? Teacher perceptions of indoor air quality and negative place attachment

The perception of indoor air quality (IAQ) in school buildings has garnered much attention. The self-reported experiences of teachers regarding the phenomenon of suffering from toxic IAQ was missing from scholarly work before the onset of the coronavirus. Toxic IAQ can be defined as the presence of toxic chemicals or compounds (including biological) in the air at levels that pose health risks and can affect a person's health, comfort, and performance (Environmental Protection Agency [EPA], 2018a).Since the onset of the pandemic, teachers are leaving the workforce in unprecedented numbers due to poor working conditions, unreasonable demands, and unrealistic expectations (Steiner & Woo, 2021). Addressing teacher retention is critical to stymie continuing teacher shortages and the adverse impact on students. This sequential mixed-methods study confronts the gap between place theory, specifically the negative emotional person-place bond, and perceived IAQ in public school buildings. Little research has been presented on the role the physical workplace has on teacher well-being and whether psychosociological environmental relationships can predict place attachment outcomes. The question of how teacher perceptions of IAQ relate to negative place attachment was explored using survey research of 242 educators in four public school districts in the Midwest. Survey data was collected April-May of 2021, with 13 follow-up purposive interviews, with the criteria of teachers' presenting negative place attachment feelings, during August 2021. The research revealed the more teachers realize their health concerns about toxic IAQ in their workplace, the more negative place attachment they feel. This involves the process of grieving, and feeling frustrated, angry, exhausted, and confused, like separation and divorce. When a teacher has crossed a threshold of divorced feelings toward the school building, they make choices: to stay employed, assigned to their building, feeling negative place attachment, ask to be reassigned, or leave. The two significant predictors of negative place attachment revealed through stepwise linear regression, were physical "healthy building" attributes and health concerns about the IEQ/IAQ in the school environment. Teachers' perceptions of aged buildings as being unhealthy, including the inoperability of classroom windows, aged carpet, and lack of ventilation were better understood by understanding what it means to occupy a workplace teachers perceive to have toxic IAQ. Employees with health conditions experienced feelings of being misunderstood, not taken seriously, and additionally faced a host of complicated social interactions with their administrators, co-workers, and family because of health ailments they attributed to their workplace. The study resulted in the creation of two new theoretic models: a revisiting of Tripartite Model of Place Attachment to include place detachment, the threshold crossed in absentia of any place attachment feelings, and an epidemiological model for addressing indoor air quality in schools and suggested interventions for practice. While these models help to develop methods, redress, and identification for negative place attachment due to indoor air quality, it was not possible to identify a consistent predictor of negative place attachment. This suggests that the themes identified in the interview process alongside a predictor model can help identify schools where intervention is essential. (PsycInfo Database Record (c) 2023 APA, all rights reserved)

Designing IAQ-Resilient Post-Pandemic Buildings

The COVID-19 pandemic has led to significant changes to human life and habits. There is an increasing urgency to promote occupants' health and well-being in the built environment where they spend most of their lives, putting indoor air quality (IAQ) in the spotlight. This study fits into this context, aiming to provide useful information about the design, construction, and operation of an IAQ-resilient building in the post-pandemic era for it to ensure a good trade-off between energy- and health-related objectives. The PRISMA guidelines were adopted to conducting a systematic review obtaining 58 studies that offered relevant results on two main research areas: (i) the concept of resilience, focusing on its definition in relation to the built environment and to pandemic-related disruptions;and (ii) the building design strategies that are able to increase buildings' resilience, focusing on the preventive measures involving engineering control. In addition, the metrics and the decision-making tools able to make IAQ-resilient buildings attractive to the investors, focusing on the cost-benefit analysis (CBA) technique, were discussed. The research supported the transition of the building sector to a human-centered approach that is able to include IAQ resilience among the main priorities of future buildings to guarantee the occupants' health and well-being. © 2023 by the authors.

THE IMPACT OF COVID-19 VENTILATION REQUIREMENTS ON THE TEMPERATURE AND AIR QUALITY IN UNIVERSITY CLASSROOMS

The current study analyzes educational buildings aiming to determine the long and short-term effects of the COVID-19 pandemic situation regarding the usage patterns and indoor environmental quality standards. Through monitoring campaigns in various classrooms, data has been gathered on temperature and indoor air quality which has made it possible to obtain a picture of the current situation in rooms with forced ventilation systems as well as in rooms where only natural ventilation is available. Results show that the CO2 concentration levels remain controlled regardless of the number of students in spaces equipped with mechanical ventilation;however, in classrooms where only natural ventilation is available, these values vary depending on the occupancy and, when attempting to maintain the recommended levels, indoor thermal conditions are greatly affected by the external weather. The factors with the greatest impact on comfort are airspeed and outside temperature, which in several cases have resulted in very low indoor temperatures that do not comply with the legally required limits. © 2022 by the authors. Licensee AEIPRO, Spain. This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (https://creativecommons.org/licenses/bync-nd/4.0/)

Evaluating methods for estimating whole house air infiltration rates in summer: implications for overheating and indoor air quality

PurposeAccurate values for infiltration rate are important to reliably estimate heat losses from buildings. Infiltration rate is rarely measured directly, and instead is usually estimated using algorithms or data from fan pressurisation tests. However, there is growing evidence that the commonly used methods for estimating infiltration rate are inaccurate in UK dwellings. Furthermore, most prior research was conducted during the winter season or relies on single measurements in each dwelling. Infiltration rates also affect the likelihood and severity of summertime overheating. The purpose of this work is to measure infiltration rates in summer, to compare this to different infiltration estimation methods, and to quantify the differences.Design/methodology/approachFifteen whole house tracer gas tests were undertaken in the same test house during spring and summer to measure the whole building infiltration rate. Eleven infiltration estimation methods were used to predict infiltration rate, and these were compared to the measured values. Most, but not all, infiltration estimation methods relied on data from fan pressurisation (blower door) tests. A further four tracer gas tests were also done with trickle vents open to allow for comment on indoor air quality, but not compared to infiltration estimation methods.FindingsThe eleven estimation methods predicted infiltration rates between 64 and 208% higher than measured. The ASHRAE Enhanced derived infiltration rate (0.41 ach) was closest to the measured value of 0.25 ach, but still significantly different. The infiltration rate predicted by the "divide-by-20” rule of thumb, which is commonly used in the UK, was second furthest from the measured value at 0.73 ach. Indoor air quality is likely to be unsatisfactory in summer when windows are closed, even if trickle vents are open.Practical implicationsThe findings have implications for those using dynamic thermal modelling to predict summertime overheating who, in the absence of a directly measured value for infiltration rate (i.e. by tracer gas), currently commonly use infiltration estimation methods such as the "divide-by-20” rule. Therefore, infiltration may be overestimated resulting in overheating risk and indoor air quality being incorrectly predicted.Originality/valueDirect measurement of air infiltration rate is rare, especially multiple tests in a single home. Past measurements have invariably focused on the winter heating season. This work is original in that the tracer gas technique used to measure infiltration rate many times in a single dwelling during the summer. This work is also original in that it quantifies both the infiltration rate and its variability, and compares these to values produced by eleven infiltration estimation methods.

Natural ventilation as a healthy habit during the first wave of the COVID-19 pandemic: An analysis of the frequency of window opening in Spanish homes

Since SARS-CoV-2 spread worldwide in early 2020, many countries established lockdowns for protection. With a main transmission by aerosols, ventilation was promoted. This article analyses natural ventilation of Spanish housing during the spring 2020. An online questionnaire was launched, obtaining for this study 1502 responses. The comparative window opening before and during confinement, and households, dwellings and home activity variables, were analysed. The binary logistic regression model before pandemic indicated that ventilating properly related to: a worse perceived IAQ (OR = 1.56);thermal adaptation measures, especially those that prefer to open/close windows (OR = 1.45);not having heating system (OR = 1.15);and using power to heat water (OR = 1.60). For the confinement period, the model highlighted: being an employee (OR = 1.88);using heavy clothing in the home (OR = 2.36);and again, open/close windows for adaptation (OR = 2.24). According to specific tasks in quarantine, frequent ventilation was boosted by: an increasing use of oven (OR = 14.81);and alteration of work-habits (OR = 2.70), sport-habits (OR = 1.79), and outdoor-activities (OR = 1.60). Thus, an adequate natural ventilation pattern during the quarantine was linked to low environmental comfort in general, by virtue of indoor air quality. This is corroborated by less acoustic-thermal insulation, worse indicators of heating use, and the adaptive response to opening/closing windows when external temperature changed. © 2022 The Authors

Air Quality Improvement in COVID-19 Pandemic: Numerical Study of ventilation system in a classroom

Air quality plays a significant role during the coronavirus pandemic. Air acts as a spreading media as well as a control measure for infection in polluted spaces. Insufficient ventilation around the building may lead to a rise of pollutants carrying the virus. One way to improve ventilation is by increasing the air change rate. This study investigates the air change rate effectiveness in reducing droplets spreading in a classroom. Cases with various layouts of inlet and outlet vents are considered, and the spread of droplets is studied. The airflow analysis shows the impact of the different ventilation layout configurations. The results show that the CFD model simulation indicates an optimum ventilation configuration to decrease the droplet spread. The discrete phase model results also determine the trajectory of droplets spread along the classroom. CFD results show that in the selected configuration, a significant number of droplets are expelled to the outside and reduce their concentration inside the classroom. © 2023, Penerbit Akademia Baru. All rights reserved.

Phytoremediation potential of indoor plants in reducing air pollutants

Indoor air quality (IAQ), specifically after the COVID-19 pandemic, has become an international issue, as humans spend 80–90% of their time in indoor microenvironments. Poor IAQ has been related to the sick-building syndrome, nasal and ocular irritations, allergies, and respiratory dysfunction, including premature deaths. Phytoremediation is a novel strategy to absorb, adsorb, assimilate or transfer/reduce air pollutants and improve the IAQ using plants. Hence, the current review aims to explore indoor plants' role in improving indoor air quality, including their purification capabilities. There is increasing evidence that various plant species (e.g., Ficus benjamina, Chlorophytum comosum, Draceana) or their parts can reliably reduce the concentration of numerous air pollutants in the indoor microenvironment and promote human wellbeing. However, the indoor air pollutants removal efficiency depends on the species of plant, various plant characteristics such as leaf size, thickness, area, photosynthetic activity, light intensity and part of plant involved, i.e., roots, leaves, wax, cuticle and stomata. Using indoor plants is one of the most cost-effective and reliable methods of making a healthier indoor environment. Better public health can be maintained at a lower cost, with less strain on the health care system, if more emphasis is placed on creating a biophilic atmosphere and increasing the use of indoor plants. However, there are no established criteria for the best indoor plants and the impact of indoor plants on various factors such as interior ventilation, temperature, humidity, etc. Therefore, further experimental research is needed that simulates the interior environment to monitor the impacts of indoor plants on factors such as humidity, temperature, ventilation, etc., in improving the microenvironment of a closed space/room. Copyright © 2022 Ravindra and Mor.

Natural ventilation as a healthy habit during the first wave of the COVID-19 pandemic: An analysis of the frequency of window opening in Spanish homes

Since SARS-CoV-2 spread worldwide in early 2020, many countries established lockdowns for protection. With a main transmission by aerosols, ventilation was promoted. This article analyses natural ventilation of Spanish housing during the spring 2020. An online questionnaire was launched, obtaining for this study 1502 responses. The comparative window opening before and during confinement and households, dwellings and home activity variables, were analysed. The binary logistic regression model before pandemic, indicated that ventilating properly related to: a worse perceived IAQ (OR = 1.56);thermal adaptation measures, especially those that prefer to open/close windows (OR = 1.45);not having heating system (OR = 1.15);and using power to heat water (OR = 1.60). For the confinement period, the model highlighted: being an employee (OR = 1.88);using heavy clothing in the home (OR = 2.36);and again, open/close windows for adaptation (OR = 2.24). According to specific tasks in quarantine, frequent ventilation was boosted by: an increasing use of oven (OR = 14.81);and alteration of work-habits (OR = 2.70), sport-habits (OR = 1.79), and outdoor-activities (OR = 1.60). Thus, an adequate natural ventilation pattern during the quarantine linked to low environmental comfort in general, by virtue of indoor air quality. This is corroborated by less acoustic-thermal insulation, worse indicators of heating use, and the adaptive response to opening/closing windows when external temperature changed.

Fuzzy Logic Controller of Indoor Air Quality Monitoring and Control System for Risk Reduction of COVID-19 Transmission

The risk of Coronavirus disease (COVID-19) was reported to be higher in the indoor environment due to poor ventilation systems. A good and efficient ventilation system in enclosed spaces can help reduce the risk of infection. Thus, it is important to monitor the efficiency of the ventilation system. Therefore, this research aims to develop an indoor air quality (IAQ) monitoring and control system using the fuzzy logic controller (FLC). Three IAQ parameters were selected in this study (temperature, relative humidity (RH), and carbon dioxide (CO2) concentration). In addition, benchmark testing was done to test the efficiency of the IAQ monitoring and control system. The system's engine is a microcontroller, which collects data on IAQ parameters, and is equipped with an exhaust fan as the ventilation strategy. The device aids in monitoring IAQ parameters and is equipped with an exhaust fan as the ventilation strategy. The device, which aids in monitoring IAQ, was created using a machine learning technique, fuzzy logic controller. The performance of the proposed air quality monitoring and control system was also investigated and validated through several experiments. The system was tested by modifying each parameter individually while keeping the controlled parameters safe. In addition, the tests were changed to include the existence of a controller in the system to see how ventilation affects the measured metrics. The test revealed that without the controller, the parameters take a long time to return to their initial values, however with the controller, the readings return to their original values faster than normal. The system also demonstrated that by following the fuzzy rules set, it is capable of handling two parameters at the same time. © 2022 IEEE.

CO2 Concentrations and Thermal Comfort Analysis at Onsite and Online Educational Environments.

In building areas with high occupancy, such as classrooms, transmission routes of SARS-CoV-2 are increased when indoor air quality is deficient. Under this scenario, universities have adopted ventilation measures to mitigate contagious environments. However, the lack of adequate equipment or designs in old educational buildings is a barrier to reach minimum requirements. This study aims to quantify the indoor air quality and thermal comfort at universities and compare it to conditions in students' households. In this regard, several classrooms in buildings of the Polytechnic University of Catalonia were monitored for temperature, CO2 concentration and relative humidity. The people who used these classrooms were surveyed about their comfort perceptions. A sample of students was also monitored at their homes where they reported to studying during the exam period. By means of point-in-time surveys, students reported their daily comfort, for comparison with the monitored data. The results show that the recommendations for CO2 concentration, temperature, and relative humidity are not always met in any of the study spaces. These factors are more critical at universities due to the high occupancy. In addition, the surveys highlighted the perception that the environment is better at home than at university.

Challenges and Actions of IAQ under COVID-19: A Survey of Taiwanese People's Perception of Epidemic Prevention and Indoor Places Certification.

COVID-19 is still spreading around the world, and the pandemic has awakened the public's attention to environmental cleanliness. This article used an online survey for people living in Taiwan, and a total of 1206 valid questionnaires were collected in October 2021. According to the survey results of Taiwanese people's awareness of and needs for epidemic prevention and IAQ, 94.4% of the respondents agreed that maintaining IAQ during the COVID-19 pandemic is very important for prevention. In addition, 95.4% of them also pointed out that the "Clean and Safe" mark certification should be promoted in public places. Finally, this article also uses hierarchical regression to analyze public perceptions of seven indoor places, including elevators, restaurants, dwellings, offices, gyms, kindergartens, and long-term care centers. The results found that: (1) from the perspective of epidemic prevention, improving IAQ through ventilation strategies could prevent the spread of the COVID-19 pandemic, and (2) from the perspective of promotion certification, the elevators, restaurants and offices could establish strengthened IAQ, dwellings, gyms and long-term care centers should emphasize the display of IAQ information in entrances and exits, and kindergartens should focus on increasing safety and reducing infection.

Response to the COVID-19 Pandemic in Classrooms at the University of the Basque Country through a User-Informed Natural Ventilation Demonstrator.

The COVID-19 pandemic has generated a renewed interest in indoor air quality to limit viral spread. In the case of educational spaces, due to the high concentration of people and the fact that most of the existing buildings do not have any mechanical ventilation system, the different administrations have established natural ventilation protocols to guarantee an air quality that reduces risk of contagion by the SARS-CoV-2 virus after the return to the classrooms. Many of the initial protocols established a ventilation pattern that opted for continuous or intermittent ventilation to varying degrees of intensity. This study, carried out on a university campus in Spain, analyses the performance of natural ventilation activated through the information provided by monitoring and visualisation of real-time data. In order to carry out this analysis, a experiment was set up where a preliminary study of ventilation without providing information to the users was carried out, which was then compared with the result of providing live feedback to the occupants of two classrooms and an administration office in different periods of 2020, 2021 and 2022. In the administration office, a CO2-concentration-based method was applied retrospectively to assess the risk of airborne infection. This experience has served as a basis to establish a route for user-informed improvement of air quality in educational spaces in general through low-cost systems that allow a rational use of natural ventilation while helping maintain an adequate compromise between IAQ, comfort and energy consumption, without having to resort to mechanical ventilation systems.

Indoor air pollution, occupant health, and building system controls—a COVID-19 perspective

The recent COVID-19 pandemic has taken a serious toll on humanity and mankind, affecting every section of society. Scientists are still trying to find out the possible transmission routes of this deadly virus, with airborne routes cited by many as a possible route of infection spread. Because airborne aerosols, dust particles, and other indoor pollutants aid in virus transmission, it becomes important to assess their roles in affecting human health. The study therefore tries to review indoor air pollution and its sources, how it impacts human health, and the role of built components and technological systems in combating indoor air pollution and in the process control infection spread also. Most of the studies have found out that there exists a need to accurately determine the airflow distribution pattern rather than relying on generic ventilation standards like ventilation rates, air change rates, and CO2 levels. Although increasing outdoor airflow rates and avoiding air recirculation are some of the suggestions given to control indoor pollution levels and infection spread, it can become challenging in areas with high ambient pollution levels. This signifies the need to incorporate additional engineering controls, sensing technologies, artificial intelligence tools, and predictive modeling methods to combat the health hazards of indoor air pollution and potential novel viruses that can emerge in the future. © 2022 Elsevier Inc. All rights reserved.

Human factors affecting ventilation in Australian classrooms during the COVID-19 pandemic: Toward insourcing occupants' proficiency in ventilation management

Underventilation in classrooms is associated with poorer academic performance and greater transmission risk of COVID-19. In a study involving data from CO2 logging in 67 classrooms in Brisbane, Australia, it was found that more than half of the classrooms monitored experienced between 5 and 50 separate instances of CO2 concentrations exceeding 1,800 ppm, a level at which cognitive performance reductions have been recorded and which is considered high risk for COVID-19 transmission. The research identifies a number of human-related factors affecting ventilation in certain classrooms, including the disabling of window operation to minimize the potential for student interference, keeping windows closed in naturally ventilated buildings to improve energy efficiency, difficult to reach switches for exhaust fans and perceptions of the likelihood of remedial action being taken. Identifying Inbodied Interaction as a useful lens to enable users themselves to better identify and remedy instances of poor IAQ, the paper contributes: (1) Insight into the CO2 concentrations experienced in Australian classrooms during the COVID pandemic;(2) Identification of human-factors contributing to the ventilation-and underventilation-of the rooms monitored;and (3) Suggestions for how to foster greater awareness of ventilation among classroom occupants and translate awareness into more active, informed, and healthier ventilation behaviors from occupants, using principles of Inbodied Interaction.

A post-occupancy study of ventilation effectiveness from high-resolution CO2 monitoring at live theatre events to mitigate airborne transmission of SARS-CoV-2.

Mass-gathering events were closed around the world in 2020 to minimise the spread of the SARS-CoV-2 virus. Emerging research on the transmission of SARS-CoV-2 emphasised the importance of sufficient ventilation. This paper presents the results of an indoor air quality (IAQ) monitoring study over 82 events in seven mechanically ventilated auditoria to support the UK government Events Research Programme. Indoor carbon dioxide concentration was measured at high resolution before, during, and after occupancy to allow for assessment of the ventilation systems. Generally, good indoor air quality was measured in all auditoria, with average IAQ found to be excellent or very good for 70% of spaces. In some auditoria, spatial variation in IAQ was identified, indicating poor mixing of the air. In addition, surface and air samples were taken and analysed for the presence of bacteria by culture and SARS-CoV-2 using RT-qPCR in one venue. SARS-CoV-2 RNA was detected on a small number of surfaces at very low copy numbers, which are unlikely to pose an infection risk. Under the ventilation strategies and occupancy levels investigated, it is likely that most theatres pose a low risk of long-range transmission of COVID-19.

Air Quality in Fitness Centers: The Impact of Ventilation Restrictions-A Case Study

To stay healthy, people frequent sports facilities. This work aimed to evaluate air pollution and comfort parameters in a fitness club in the post lockdown period (due to the COVID-19 pandemic), focusing on particulate material (PM10, PM2.5) and gaseous pollutants (total volatile organic compounds-TVOCs, carbon dioxide-CO2, and carbon monoxide – CO). Sampling was carried out for 10 consecutive days in October 2020 in one fitness center (Oporto, Portugal). The results showed that indoor PM10 ranged from 1.4 to 122.5 µg/m3 and PM2.5 was between 0.8 and 25 µg/m3;the overall levels were in accordance with the current legislation. TVOC means were 0.39 mg/m3 when not occupied and 0.43 mg/m3 when exercising subjects were present, thus also fulfilling the limit 0.6 mg/m3). Average CO2 was 1400 mg/m3 with temporal maxima (2660-2894 mg/m3) exceeding the protection threshold. Finally, temperature and relative humidity exceeded the recommended comfort levels, especially during group activity classes. © 2022, Universidade do Porto - Faculdade de Engenharia. All rights reserved.

A systematic review of building systems and technologies to mitigate the spread of airborne viruses

Purpose>The purpose of this study is to conduct a rigorous systematic literature review and present a summary of building systems and technologies that can be used to mitigate the spread of airborne viruses. With the recent outbreak of COVID-19, occupants’ health and indoor air quality (IAQ) have become a critical issue for facility managers to maintain the full functionality of the buildings. An improved understanding of these available systems will help facility managers and building owners to protect the health and safety of building occupants.Design/methodology/approach>The PRISMA protocol was used for defining the literature search methodology. The concept mapping technique was used for determining the keywords. The keywords were then used to search for relevant articles using the Scopus database and Google Scholar. A thorough bibliometric analysis and qualitative analysis were conducted for the selected publications.Findings>It was found that sensor technologies, botanical air-filtration systems and artificial intelligence could be used to effectively monitor and improve IAQ. In addition, natural ventilation is one of the low-cost and effective methods of reducing contaminants from the indoor air. Computational fluid dynamic modeling can be used to understand the flow of virus particles within the building through the heating, ventilation and air-conditioning (HVAC) system. Several changes to the HVAC system are also discussed.Originality/value>This study contains a diversity of methods from the existing literature that were systematically selected to present the state-of-the-art building systems and technologies that can effectively improve IAQ. The researchers plan to follow up on the findings of this research and will conduct an empirical study to assess its impact on IAQ.