Introduction: Our aim was to gain insight into the effect of COVID-19 measures on SARS-CoV-2 incidence in secondary schools and the association with classroom CO 2 concentration and airborne contamination. Methods: Between October 2020—June 2021, 18 schools weekly reported SARS-CoV-2 incidence and completed surveys on school-initiated COVID-19 measures (e.g. improving hygiene or minimizing contacts). CO 2 was measured in occupied classrooms twice, and SARS-CoV-2 air contamination longitudinally using electrostatic dust collectors (EDC) and analyzed using RT-qPCR. National COVID-19 policy measures varied during pre-lockdown, lockdown and post-lockdown periods. During the entire study, schools were recommended to improve ventilation. SARS-CoV-2 incidence rate ratios (IRR) were estimated by Generalized Estimating Equation (GEE) models. Results: During 18 weeks follow-up (range: 10–22) SARS-CoV-2 school-incidence decreased during national lockdown (adjusted IRR: 0.41, 95%CI: 0.21–0.80) and post-lockdown (IRR: 0.60, 0.39–0.93) compared to pre-lockdown. School-initiated COVID-19 measures had no additional effect. Pre-lockdown, IRRs per 10% increase in time CO 2 exceeded 400, 550 and 800 ppm above outdoor level respectively, were 1.08 (1.00–1.16), 1.10 (1.02–1.19), and 1.08 (0.95–1.22). Post-lockdown, CO 2-concentrations were considerably lower and not associated with SARS-CoV-2 incidence. No SARS-CoV-2 RNA was detected in any of the EDC samples. Conclusion: During a period with low SARS-CoV-2 population immunity and increased attention to ventilation, with CO 2 levels most of the time below acceptable thresholds, only the national policy during and post-lockdown of reduced class-occupancy, stringent quarantine, and contact testing reduced SARS-CoV-2 incidence in Dutch secondary schools. Widespread SARS-CoV-2 air contamination could not be demonstrated in schools under the prevailing conditions during the study. @en

A previous study clustered home occupants into archetypes with a questionnaire. This study uses qualitative methods to strengthen those previously-found archetypes with data pertaining to the participants’ home experiences. Focus groups were carried out where generative activities were conducted involving the generation of collages. The first activity dealt with the expression of ‘meaning of energy use at home’ and the second one with the ‘ideal home experience’. Analyses were done with content and thematic analysis. Codes were drawn from the data and were assimilated through an affinity diagram. The diagram produced two categories: building themes and human themes, along with five sub-categories (home, financial, energy, psychological, and behavioural aspects). The outcome shows that each archetype expresses needs and meanings of an ideal home experience and energy use differently from each other. The results provide evidence that generative techniques can be used in energy research. In this case, to validate and substantiate the quantitative archetypes previously produced with a questionnaire. Interpretive knowledge in energy research allows for a better understanding of occupants’ differing behavioural patterns in regards to energy use and comfort. It allows customizing interventions to the archetypes’ specific needs to decrease energy consumption while maintaining comfort.@en

The thermal environment in educational buildings is crucial to improve students’ health and productivity, as they spend a considerable amount of time in classrooms. Due to the complexity of educational buildings, research performed has been heterogeneous and standards for thermal comfort are based on office studies with adults. Moreover, they rely on single dose-response models that do not account for interactions with other environmental factors, or students’ individual preferences and needs. A literature study was performed on thermal comfort in educational buildings comprising of 143 field studies, to identify all possible confounding parameters involved in thermal perception. Educational stage, climate zone, model adopted to investigate comfort, and operation mode were then selected as confounding parameters and discussed to delineate the priorities for future research. Results showed that children often present with different thermal sensations than adults, which should be considered in the design of energy-efficient and comfortable educational environments. Furthermore, the use of different models to analyse comfort can influence field studies’ outcomes and should be carefully investigated. It is concluded that future studies should focus on a more rational evaluation of thermal comfort, also considering the effect that local discomfort can have on the perception of an environment. Moreover, it is important to carefully assess possible relationships between HVAC systems, building envelope, and thermal comfort, including their effect on energy consumption. Since several studies showed that the perception of the environment does not concern thermal comfort only, but it involves the aspects of indoor air, acoustic, and visual quality, their effect on the health and performance of the students should be assessed. This paper provides a way forward for researchers, which should aim to have an integrated approach through considering the positive effects of indoor exposure while considering possible individual differences.@en

To study the combined effect of different environmental factors on children in a classroom setting, 250 children from seven primary schools were exposed to 36 different environmental configurations (‘all’ and ‘fewer’ acoustical panels; ‘displacement’ and ‘mixing’ ventilation; sound type: ‘children talk’, ‘traffic’, and ‘none’; and ‘direct’, ‘indirect’ and ‘soft’ lighting). In a four-way factorial design, they assessed with 18 groups on eight different days temperature, draught, noise, light and smell. Correlation, three-way ANOVA, comparison tests and multi-regression analysis were used to analyse relationships, and main, cross-modal and interaction effects. The results show that more acoustical panels had a positive effect on the children’s assessment of sound. Sound type had a main effect on the assessment of sound. Statistical significant cross-modal effects were found for lighting and sound type on the assessment of smell. Significant three-way interactions between ‘Vent’, ‘Sound’, and ‘Light’ types were found for smell and light in the ‘fewer panels’ situations; and for light in the ‘all panels’ situations. Multiple-regression analysis also showed that perception of smell was significantly related with draught, sound and light perception in ‘fewer panels’ conditions. Further studies on these cross-modal interactions are recommended, specifically at individual level.@en

Because of COVID-19, the indoor environmental quality (IEQ) in sports facilities has been a concern to environmental health practitioners. To develop an overall understanding of the available guidelines and standards and studies performed on IEQ in sports facilities, an extensive literature study was conducted, with the aim of identifying: (1) indicators that are being used to assess IEQ in different sports facilities; (2) indicators that are potentially interesting to be used to assess indoor air, in particular; (3) gaps in knowledge to determine whether sports facilities are safe, healthy and comfortable for people to stay and perform their activities. The outcome indicates that most current standards and previous investigations on IEQ in sports facilities mainly focused on dose-related indicators (such as ventilation rate), while building-related indicators (such as ventilation regime) and occupant-related indicators (such as IEQ preferences) were rarely considered. Little attention is given to the fact that ventilation systems may play an important role in the air quality of the location, and few investigations have been performed on the transmission of SARS-CoV-2. This study recommends more research into both occupant and building-related indicators as well as cross-modal effects between various IEQ factors for developing future standards on sports facilities.@en

This is an account that should be heard of an important struggle: the struggle of a large group of experts who came together at the beginning of the COVID-19 pandemic to warn the world about the risk of airborne transmission and the consequences of ignoring it. We alerted the World Health Organization about the potential significance of the airborne transmission of SARS-CoV-2 and the urgent need to control it, but our concerns were dismissed. Here we describe how this happened and the consequences. We hope that by reporting this story we can raise awareness of the importance of interdisciplinary collaboration and the need to be open to new evidence, and to prevent it from happening again. Acknowledgement of an issue, and the emergence of new evidence related to it, is the first necessary step towards finding effective mitigation solutions.@en

Previous studies indicate that acoustic improvements at classroom-level, such as using ceiling panels, do not work well to solve noise problems in classrooms. Therefore, this study introduced a new way – individual control – to improve classroom acoustics. The acoustic effect of five different classroom settings is simulated: two individual-level acoustic improvement settings (“Single-sided canopies” and “Double-sided canopies”), two classroom-level acoustic improvement settings (“Half-ceiling” and “Full-ceiling”), and one “Control” setting. The simulation was accomplished with Computer Aided Theatre Technique (CATT-Acoustic™), which is a ray-tracing-based room acoustics prediction software package. According to the two main ways of using classrooms (instruction and self-study), the simulations were run for two situations: instruction situation and self-study situation, and the Lombard Effect was taken into consideration in the self-study situation. The results showed that in both situations, all of these improvement settings, compared with the “Control” setting, could shorten the reverberation time and increase the speech transmission index, and the improvements caused by the individually controlled canopies were more obvious than caused by the ceiling panels. Additionally, in the instruction situation, the individual-level improvements could increase the sound pressure level of the teacher's speech, while in the self-study situation, the individual-level improvements could decrease the sound pressure level of other children's talk. In the future, it is recommended to produce and test different individually controlled devices in a lab or real classroom to verify these results.@en

Due to the increasing demand for healthcare and the large impact on the finance of hospital buildings in the near future, study is needed on aspects that affect health and comfort of patients and staff in hospitals. Therefore, a literature review was performed on studies related to specific hospital departments and occupant groups, in order to contribute to a better understanding of relations of comfort and health indicators and the physical environment. Differences in comfort and health of occupants were compared between departments, and between occupant groups. It was concluded that staff was generally less satisfied than patients were. Some of the indicators studied (occupant, dose and building-related indicators) varied between departments. Most studies focused on a single dose or building-related indicator, although the occupant-related indicators, such as privacy, infection rate or mortality, were related to more than one dose or building-related indicator. It was concluded that staff in particular have been understudied in relation to the variation of health and comfort aspects in different departments.@en

Sounds (e.g., human activity, nature, building systems) are one of the indoor environmental stimuli that may have positive and/or negative effects on students’ well-being and performance in educational buildings. Students in educational buildings have individual acoustical preferences and needs as portrayed by occupant-related indicators, for example perception. Acoustical guidelines for educational buildings are generally focused on acoustical performance in terms of dose-related (e.g., sound pressure level) and building-related indicators (e.g., sound absorbing walls), while occupant-related indicators (e.g., heart rate) are rarely mentioned. In contrast, previous studies such as indoor soundscape studies, do take into consideration occupant-related indicators, including physiological and psychological. Therefore, this study aimed at summarizing these indicators in a comprehensive overview that is essential for investigating the students’ acoustical preferences and needs in educational buildings. A literature review of relevant studies in the domain of indoor acoustics and soundscape was carried out. A number of key indicators (occupant-related, dose-related, building-related) and methods that are fundamental to be considered were identified. Only in a few studies, students’ acoustical preferences and needs were investigated by considering occupant-related indicators (both physiological and psychological). In addition, dose-related indicators of other indoor environmental quality (IEQ) factors and building-related indicators were rarely taken into account in previous studies.@en

Airborne transmission of small respiratory droplets (i.e., aerosols) is one of the dominant transmission routes of pathogens of several contagious respiratory diseases, which mainly takes place between occupants when sharing indoor spaces. The important role of ventilation in airborne infection control has been extensively discussed in previous studies, yet little attention was paid to the situation in school classrooms, where children spend long hours every day. A literature study was conducted to identify the existing ventilation strategies of school classrooms, to assess their adequacy of minimizing infectious aerosols, and to seek further improvement. It is concluded that school classrooms are usually equipped with natural ventilation or mixing mechanical ventilation, which are not fully capable to deal with both long-range and short-range airborne transmissions. In general, the required ventilation designs, including both ventilation rates and air distribution patterns, are still unclear. Current standards and guidelines of ventilation in school classrooms mainly focus on perceived air quality, while the available ventilation in many schools already fail to meet those criteria, leading to poor indoor air quality (IAQ). New ways of ventilation are needed in school classrooms, where the design should be shifted from comfort-based to health-based. Personalized ventilation systems have shown the potential in protecting occupants from aerosols generated within short-range contact and improving local IAQ, which can be used to compensate the existing ventilation regimes. However, more studies are still needed before such new ventilation methods can be applied to children in school classrooms.@en

Occupants’ comfort perception affects building energy consumptions. To improve the understanding of human comfort, which is crucial to reduce energy demand, laboratory experiments with humans in controlled environments (test rooms) are fundamental, but their potential also depends on the characteristic of each research facility. Nowadays, there is no common understanding for definitions, concepts, and procedures related to human comfort studies performed in test rooms. Identifying common features would allow standardising test procedures, reproducing the same experiments in different contexts, and sharing knowledge and test possibilities. This review identifies 187 existing test rooms worldwide: 396 papers were systematically selected, thoroughly reviewed, and analysed in terms of performed experiments and related test room details. The review highlights a rising interest in the topic during the last years, since 46% of related papers has been published between 2016 and 2020. A growing interest in non-thermal sensory domains (such as visual and air quality) and multi-domain studies about occupant's whole comfort emerged from the results. These research trends have entailed a change in the way test rooms are designed, equipped and controlled, progressively becoming more realistic inhabitable environments. Nevertheless, some lacks in comfort investigation are highlighted: some continents (like Africa and South America) and climate zones are found to be underrepresented, while involved subjects are mainly students performing office tasks. This review aspires to guide scientists and professionals toward the improved design or the audit of test room experimental facilities, especially in countries and climate zones where human comfort indoors is under-studied.@en

What is Senselab? The ‘SenseLab’, a playground for the senses, is a laboratory for testing and experiencing single and combinations of indoor environmental conditions.@en

There are indications that energy-retrofitted buildings can create risks for indoor environmental quality (IEQ) and therefore for health and comfort of occupants. A review was conducted to identify and verify those risks, within three themes: building envelope, heating, ventilating and air conditioning (HVAC)-systems, and occupants. Publications from the last five years in major peer-reviewed journals from different fields (energy, buildings, indoor air, social sciences) were found by using a variety of keywords (health effects, occupant behaviours, energy-efficient retrofitting, etc.). For the building envelope, retrofitted buildings tend to be air-tighter and more thermally insulated. Hence, humidity problems, build-up of pollutants, and overheating may occur. Installing HVAC-systems and issues within (ducts, filters, maintenance, noise) may also compromise IEQ. Although relationships are difficult to establish, evidence shows that certain retrofits increase the risk of health problems, particularly for airways, skin, and eyes. Despite the installation of energy-retrofitting technologies, not all buildings lower their energy consumption. This is partly due to occupants (behaviours, preferences, needs, awareness) and partly due to technical issues. The studies reviewed, mainly focused on the performance gaps of energy-retrofitted homes and on energy-saving measures. “Comfort” and “health” tend to be disregarded, with both being seldom measured and only assessed by simulation. Occupant behaviours, preferences, and needs are understudied and need to be incorporated into the research and development of retrofitting measures. More interdisciplinary approaches are needed, in which buildings & HVAC-systems, occupants, health and comfort, and IEQ are investigated as interacting elements and based on an integrated approach.@en

During the COVID-19 pandemic, the importance of ventilation was widely stressed and new protocols of ventilation were implemented in school buildings worldwide. In the Netherlands, schools were recommended to keep the windows and doors open, and after a national lockdown more stringent measures such as reduction of occupancy were introduced. In this study, the actual effects of such measures on ventilation and thermal conditions were investigated in 31 classrooms of 11 Dutch secondary schools, by monitoring the indoor and outdoorCO2 concentration and air temperature, both before and after the lockdown. Ventilation rates were calculated using the steady-state method. Pre-lockdown, with an average occupancy of 17 students, in 42% of the classrooms the CO2 concentration exceeded the upper limit of the Dutch national guidelines (800 ppm above outdoors),while 13% had a ventilation rate per person (VRp) lower than the minimum requirement (6 l/s/p). Post lockdown, the indoor CO2 concentration decreased significantly while for ventilation rates significant increase was only found in VRp, mainly caused by the decrease in occupancy (average 10 students). The total ventilation rate per classrooms, mainly induced by opening windows and doors, did not change significantly. Meanwhile, according to the Dutch national guidelines, thermal conditions in the classrooms were not satisfying, both pre and post-lockdown. While opening windows and doors cannot achieve the required indoor environmental quality at all times, reducing occupancy might not be feasible for immediate implementation. Hence, more controllable and flexible ways for improving indoor air quality and thermal comfort in classrooms are needed.@en

To identify current problems in the classroom and to conceptualize design solutions by primary school children to solve these problems, 335 children from seven primary schools participated in a workshop held in the Experience room of the SenseLab, comprising of two parts. In part 1, the children were asked to think about their own classroom at school and to choose an IEQ-problem in their own classroom that they are bothered with. In part 2 of the workshop, the children were asked to imagine they are an inventor or scientist in 2040 with all resources available and to make a design for the future. The content analysis of the problems and solutions appearing in the drawings and the written text resulted in 5 themes (light, noise, temperature, air and other than IEQ) and 16 sub-themes (11 for the problems and 5 for the solutions). Noise-related problems were most frequently reported (58%), followed by temperature (53%), air (22%), and light (16%). Girls reported more problems than boys, which is possibly related to a better recollection of negative feelings towards those problems in their classrooms. 47% of the children proposed solutions related to more than one IEQ-problem. Solutions ranged from existing solutions, for example headphones to protect against noise to far-fetched solutions such as send noisy children away by means of a rocket. The outcome showed that children can be valuable contributors in co-designing ‘new’ or ‘adapted’ classroom environments.@en

People living in short-term rental housing, henceforth temporary housing, are rarely consulted by professionals involved in the design process, whether regarding new or refurbished buildings. Knowing what is required for temporary dwellers to feel at home and how their meanings of home relate to household characteristics, activities, and indoor environmental quality, might result in better designs for these commonly small dwellings. To explore the views of temporary occupants about their home environment, we designed and conducted a survey directed to young people in the Netherlands, likely to be familiar with living in temporary accommodation (141 university students, 58 refugees who have received a permit to stay; henceforth named permit holders), 23 persons who were working 4 days and studying 1 day; henceforth named starters). Through factor analysis, six meanings of home were found to be statistically significant: Representation, privacy, sociability, rootedness, future, and appropriation. Multiple regression analyses and analyses of variance indicated that meanings of home were related to some household characteristics and the presence of light and cleanliness. Our study showed that measuring meanings of home might help understand not only how dwellings are used but also how to improve the design of small temporary dwellings. For instance, more possibilities for good or natural light, storage, and the display of personal possessions should be incorporated into the design of these small dwellings.@en

Vegetation systems in combination with biofiltration processes are emerging processes that are expected to have beneficial effects on the improvement of indoor air quality (IAQ). Common indoor plants may provide a valuable strategy to avoid rising levels of indoor air pollution. In an active vegetation system air cleaning rates may be significantly higher than in passive vegetation systems using active fan-assisted hydroponics technology, which draws the air through the root rhizomes of the plants. However, to evaluate the real effect of active green systems on IAQ it is important to create a reliable experimental setup and protocol regarding not only components of the prototype but also the methods for analysis and evaluation.@en

Objectives Ocular discomfort is a prevalent health complaint in offices. It is hypothesized that, in addition to individual and occupational factors, the buildings' indoor environment may affect eye complaints. However, insight in potential building-related causal factors, needed to allow development of effective prevention strategies in building design, operation and maintenance is limited. This study aimed to investigate the relations between modern office building characteristics and dry eye complaints. Methods Comprehensive characteristics of 167 office buildings in eight European countries, were linked to questionnaire data from 7441 office workers. Multilevel modeling was applied to explore relations between building characteristics and self-reported dry eye complaints, in a cross-sectional study. Results Among office workers investigated, 34% declared dry eye complaints during the past four weeks. Majority of workers (91.2%) experiencing these symptoms, reported improvement on days away from the office. After full adjustment, the regression model revealed a significant increased risk for: proximity (<100 m) to potential sources of outdoor air pollution (OR: 1.41, 95% CI: 1.06–1.88), absence of operable windows (OR: 1.70, 95% CI: 1.34–2.16), portable humidifiers in the offices (OR: 1.58, 95% CI: 1.18–2.11), exposed concrete and/or plaster (OR: 1.29, 95% CI 1.02–1.62) and dispersion and/or emulsion paint as wall covering in offices (OR: 1.20, 95% CI: 1.01–1.41). A negative association was found for cleaning surfaces at least once per week (OR: 0.75, 95% CI: 0.61–0.91). Conclusions Building characteristics were associated with dry eye complaints of office workers. Focused studies are recommended to investigate underlying causes to prevent these symptoms.@en

There is a need for reducing dwellings’ energy consumption while maintaining a comfortable and healthy indoor environment. This review was performed to provide a steppingstone for identifying new methods for studying everyday home energy use and comfort. First, an overview of comfort is given as seen from different disciplines, depicting the subjective and multidimensional nature of comfort. This is followed by the biological component of comfort, reflected as an emotional, behavioural, and physiological reaction to environmental stimuli. Subsequently, links between comfort, health, and wellbeing are introduced. The second part of the review focuses on energy and buildings, with the connection between energy and behaviours-detailing possible explanations of performance gaps, and the pathways from energy to health. To conclude, human sensation of comfort is more complex than the perception of thermal, acoustical, visual stimuli, or air quality environment. Comfort is a reaction to the environment that is strongly influenced by cognitive and behavioural processes. Habits and controllability have been identified as paramount in the links between comfort and energy consumption. In this holistic view of comfort linked to health, comfort is referred to as ‘wellbeing’. The first steps for new directions of the study of comfort and energy are presented.@en

Research has shown that staying indoors is not good for our health. People spend more and more of their time indoors. Therefore, providing a healthy and comfortable indoor environment is very important. The SenseLab will contribute to the understanding of and coping with the indoor environment. Students, teachers, researchers, but also the general public are able to experience and test different combinations of environmental conditions. The SenseLab is built around the four indoor environmental quality (IEQ) factors (air, thermal, light and acoustical quality), including: the experience room, for integrated perception of IEQ, so studying all factors together. And four test chambers, open to the public, where you can take a sniff of materials, feel heat and cold, see how light influences perception and experience how acoustics can be improved. A genuine playground for your senses.@en