Recent studies have shown that both personal and building-related factors may affect the health and comfort of occupants in their homes. It is also known that people differ in their needs and can therefore respond differently to these stressors. Therefore, based on the large database from the survey conducted yearly from 2016 to 2020 among the first-year students of the faculty of Architecture and the Built environment at the Delft University of Technology, this study aimed to explore the associations between self-reported rhinitis/stuffy nose/migraine/headache, and the indoor environment of the students' homes, taking into account potential confounders and profiles. Two-steps cluster analysis resulted in three profiles of students based on their IEQ-related perceptions: Cluster 1 with the highest reported percentage of symptoms and the lowest reported percentage of diseases; Cluster 2 with moderate reported symptoms and diseases; and Cluster 3 with the lowest percentage of reported symptoms and the highest percentage of reported diseases. Logistic regression modelling showed that risk factors contributing to having rhinitis, stuffy nose, migraine and/or headache, differ per cluster, and showed little overlap with the all-respondents group. Moreover, when there is an overlap, the associated risk factor might increase the risk for one cluster, while for another it decreases the risk, indicating differences in response between the different clusters; and therefore, the importance of clustering instead of considering all respondents as one.@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

Building retrofitted to be resilient in the face of future climates may present risks for the health and comfort of the occupants, due to the indoor environmental quality changes involved under current building practices. This chapter is a literature review of recent peer-reviewed papers from a variety of fields identifying such potential hazards. Three topics are investigated: building envelope, HVAC systems and occupants. In terms of the building envelope, resilient buildings currently lead to more airtightness and thermal insulation, which can create humidity problems, accumulation of air pollutants or overheating. HVAC systems, however efficient, can jeopardize the indoor environmental quality, through ducts, filters, noise and maintenance. Respiratory system, eyes and skin conditions can arise with certain retrofitting measures. Moreover, such measures do not necessarily lead to energy savings, partly due to the occupants and their behaviours and partly due to the technologies and their feedback. Human factors should be combined into the development of retrofitting technologies. Thus, interdisciplinarity is needed to develop resilient buildings that will be energy-efficient and also healthy and comfortable for their occupants and the technologies need to be researched as interdependent components to be synthesized in their performance to result in a single enhanced goal.@en

Due to the COVID-19 pandemic, a large number of office workers were required to conduct their work from home. Little is known about the indoor environmental quality (IEQ) preferences and psychosocial comfort preferences of staff working from home. Therefore this study aimed to cluster office workers working at home based on their self-reported preferences for IEQ and psychosocial comfort at their most used workspace and to identify these preferences and needs of workers during the COVID-19 pandemic. A questionnaire was administered to employees of ten offices in the Netherlands, and the 502 respondents were clustered with two models by using TwoStep cluster analysis. The first model was based on variables related to IEQ preferences, while the second was to psychosocial comfort preferences. The analysis revealed four IEQ clusters and six psychosocial comfort clusters. Comparison of these results with other similar studies proposed that the prevalence of anxiety, depression, migraine, and rhinitis, increased for this population during the work-from-home period of the pandemic. Further results suggest that both IEQ and psychosocial comfort preferences are situation- and gender-dependent.@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

Background: The initial aim was to study the effects of face masks worn by recently infected individuals on the airborne spread of SARS-CoV-2, but findings motivated us to proceed with comparing the presence of SARS-CoV-2 in air samples near infected individuals at home with those near infected intensive care unit (ICU) patients. Aim: To assess the presence of SARS-CoV-2 in the air of homes of infected individuals and in ICU rooms of critically ill patients with COVID-19 who were undergoing different forms of potential aerosol-generating medical procedures. Methods: A high-volume air sampler method was developed that used a household vacuum cleaner with surgical face masks serving as sample filters. SARS-CoV-2 RNA was harvested from these filters and analysed by polymerase chain reaction. Fog experiments were performed to visualize the airflow around the air sampler. Air samples were acquired in close proximity of infected individuals, with or without wearing face masks, in their homes. Environmental air samples remote from these infected individuals were also obtained, plus samples near patients in the ICU undergoing potential aerosol-generating medical procedures. Findings: Wearing a face mask resulted in a delayed and reduced flow of the fog into the air sampler. Face masks worn by infected individuals were found to contain SARS-CoV-2 RNA in 71% of cases. SARS-CoV-2 was detected in air samples regardless of mask experiments. The proportion of positive air samples was higher in the homes (29/41; 70.7%) than in the ICU (4/17; 23.5%) (P < 0.01). Conclusion: SARS-CoV-2 RNA could be detected in air samples by using a vacuum cleaner based air sampler method. Air samples in the home environment of recently infected individuals contained SARS-CoV-2 RNA nearly three times more frequently by comparison with those obtained in ICU rooms during potential aerosol-generating medical procedures.

@en

The worldwide spread of the Coronavirus disease 2019 forced governments to enact different measures to mitigate the infections. Employers and workers had to adjust by shifting a substantial number of jobs to a “work from home” configuration (WFH). On average, people used to spend around 90% of their time indoors, however, this number may have increased during the pandemic. This study aims to investigate the health status of office workers after nine months of a WFH format during the lockdown. A questionnaire was developed to assess the self-reported during the lockdown of office workers. A link to the questionnaire was sent to the employees of ten offices across the Netherlands, in November of 2020. A total of 502 employees responded to the questionnaire, which included diseases suffered during the last twelve months (i.e. asthma, wheezing, rhinitis, hay fever, anxiety, migraine, etc.). Data were analyzed by performing descriptive statistics of the general characteristics and the health status. The results show that during the lockdown and WFH, conditions such as eczema, depression and anxiety are higher than the average prevalence during non-lockdown situations. This may be due to lifestyle changes, such as reduced social interactions, increased distractions, and increased uncertainty.@en

The airborne transmission of SARS-CoV-2 in educational buildings has raised concerns during the current COVID-19 pandemic. In this study, a portable fog generator system was designed and assembled to visualise the airflow pattern of exhaled droplets in a classroom. The system consists of five components: medium, fog generator, buffer, pump, and manikin head. The medium was made of glycol and demineralised water, which produced a fog composed of droplets. The fog was produced with the fog generator and passed through a pipe into the buffer for build-up. After accumulation, the fog is pumped through another pipe and is exhaled out of the mouth of the manikin. Experiments were conducted with the portable fog generator system in a simulated classroom under four different ventilation regimes: no ventilation, natural ventilation (open windows and door), mixing ventilation (600 m3/h), and a combination of natural + mixing ventilation. The experiments were recorded with a camera and analysed to determine the horizontal distance of the path taken by the fog and to measure the time it remained visible after exhalation from the mouth. During the experiments, it could be observed with the naked eye that the glycol droplets linger in the air longer than what was captured in the recordings. Not all the droplets were visible with the camera. The recordings showed that with open windows and door (natural ventilation), the droplets travelled the furthest distance (1.8 m) and stayed the longest in the air, while with mixing and natural ventilation, the droplets travelled the shortest (0.5 m) and stayed the least time in the air. These findings confirm that mechanical mixing ventilation increases the removal of aerosols in the air. It is concluded that the portable fog generator system provides a quick method in understanding the duration and distance droplets can travel after being exhaled.@en

During the COVID-19 outbreak, university courses were shifted online and students spent the majority of their time inside their homes. However, staying indoors can affect students’ health due to the exposure to several environmental stressors, such as background noise, and/or inefficient ventilation, and/or insufficient lighting. Previous studies showed that the indoor environmental factors may cause health effects on students (physiological and psychological). Therefore, this research aimed at investigating the differences in students’ health and psychosocial status between before and during COVID-19. An online questionnaire survey was completed by first-year undergraduate university students in March 2019, 2020, and 2021. This questionnaire includes questions about time spent at home, psychosocial status, diseases, and home-related symptoms. The mean number of hours that students spent at home during the weekdays and on weekends were calculated, respectively. Besides, occurrence frequencies of psychosocial statuses were calculated for each year. Furthermore, a statistical analysis, including one-way ANOVA and Chi2, were performed to examine the differences between the three groups in terms of time spent at home, psychosocial statuses, diseases, and home-related symptoms. It is worthwhile to note that students spent significantly more time at home, during the COVID-19 pandemic in March 2021. Another notable result is that students’ mood and emotional states changed significantly over the three years; for example, fewer students reported to be active and inspired in 2021. Moreover, the home-related symptoms, such as headache and tiredness, significantly increased in 2021, compared with the other two years.@en

While the pressure on hospital workers keeps growing, they are generally more dissatisfied with their comfort than other occupants in hospitals or offices. To better understand the comfort of outpatient workers in hospitals, clusters for preferences and perceptions of the indoor environmental quality (IEQ) and social comfort were identified in a previous study before the outbreak of the coronavirus disease 2019 (COVID-19) pandemic. This qualitative study explains the outpatient workers’ main preferences for comfort during the COVID-19 pandemic. Semi-structured interviews and photo-elicitation were used. Contextual changes due to the COVID-19 pandemic were included. The questions in the interviews were based on the characteristics of the profiles, corresponding with the clusters. The data were analyzed with content analysis according to the steps defined by Gioia. Seventeen outpatient workers who had been part of the previous study participated. For some outpatient workers differentiation of preferences was illogical due to interrelations and equal importance of the comfort aspects. The main changes in perceptions of comfort due to the pandemic were worries about the indoor air quality and impoverished interaction. Because the occupants’ preferences for comfort can change over time, it was suggested that further development of occupant profiles needs to accommodate changes.@en

3D-printing has transformed traditional manufacturing by enabling the fabrication of individually designed complex systems. The building’s façade is one of the most challenging systems because it affects the control of the built indoor environment and allows to provide energy-saving. The objective of this research is to distinguish 3D-printing technologies and applied materials in them that improve transparency in the façade to decrease artificial lighting consumption, to control solar energy, and to improve energy-savings. A literature study was performed, firstly, different 3D-printing techniques and their materials for producing transparent outcomes were reviewed from academic databases. Then, transparent 3D-printed façade prototypes were identified. The outcomes indicated that most of the prototypes used the FDM 3D-printing technique and Polyethylene Terephthalate Glycol as a material. These prototypes didn’t consider the disadvantages of the FDM technique for the lighting transmission. Additionally, some prototypes have control over daylighting discomforts but some of them not. Prototypes tried to improve energy-saving which ranged from applying recyclable materials to controlling solar gain.@en

Building-related health symptoms are multifactorial, hence a comprehensive study is needed to identify associations of such symptoms with building aspects. Previous studies have identified certain building characteristics as risk factors for both dry eyes and headaches, which are among the most prevalent symptoms suffered by office workers. This study investigated associations of dry eyes and headaches with building characteristics in outpatient areas because these conditions may vary between office and hospital buildings. A survey was performed in six hospital buildings, which included administering a questionnaire to 556 outpatient workers and an inspection of the building locations, services and 127 outpatient rooms. Multivariate regression models were produced for dry eyes and headaches. Both models were adjusted for personal and work-related aspects. The prevalence of self-reported dry eyes and headaches in outpatient areas was related to building-related aspects that affect the indoor air quality and visual quality, and to room types. In general, this study is consistent with previous office studies. However, a specific finding of this study is the association of the most frequently used room types and the presence of a window to the corridor with dry eyes and headaches.

@en

Due to the SARS-CoV-2 pandemic, several strategies have been proposed to reduce its transmission, from social distancing, regularly disinfecting items and hands, and wearing barrier masks. Guidelines and standardization propose certain tests for the filtration of the masks, or visual inspections to check the materials. However, no standards exist to tests the outward leakage through the face seal perimeter of the masks. Therefore, the aim of this study was to develop a method to visualize and quantify respiratory droplets, simulated by ‘mist’, exhaled by a mask wearer. A setup was developed with fluorescent ink, UV lights, background subtraction, to highlight the mist and its footage. Mist was quantified with a software, and one-way ANOVAs and t-tests were conducted on the means, to assess the reliability of the method. The results of the statistical tests suggest that the method is reliable to visualize and quantify the mist.@en

Next to personal, psychosocial and physiological aspects, environmental aspects of homes may affect the health and comfort of their occupants. This study aimed to investigate the multifactorial character of both rhinitis and headaches among five groups of students from universities in five different cities: Taichung (Taiwan), Concepcion (Chile), Paramaribo (Suriname), Beijing (China) and Delft (The Netherlands). Among the students studied, 18% declared having suffered from rhinitis in the last 12 months, and 30% from headaches in the last 3 months. Self-reported characteristics of 682 students and their homes were linked to self-reported rhinitis and headaches. Logistic regression modelling was applied to explore relations between building-related factors and rhinitis, and between building-related factors and headaches. After full adjustment, the regression model for both rhinitis and headaches confirmed their multifactorial character. While personal-related factors family rhinitis and age were associated with rhinitis, negative events and PANAS negative were with headaches. Biological pollutants (caused by pets) were associated both with rhinitis and headaches; chemical pollutants, caused by open bookshelves and lack of sweeping floors, were associated with rhinitis. The study concludes that the identified risk factors seemed independent of season or climate region.@en

High efficiency air filtration has been suggested to reduce airborne transmission of ‘infectious’ aerosols. In this study the ‘air cleaning’ effect as well as the effect on sound and air velocity (draught risk) of a mobile High-Efficiency Particulate Air (HEPA) filter system was tested for different settings and positions in the Experience room of the SenseLab. From both the noise assessments by a panel of subjects and sound monitoring it was concluded that the mobile HEPA filter system causes an unacceptable background sound level in the tested classroom setting (Experience room). With respect to the air velocity measurements and draught rating calculations, it was concluded that both depend on the position and the setting of the HEPA filter system as well as on the position and height of the measurements. For the removal of aerosols simulated by air-filled soap bubbles in front of the subject, the mobile HEPA filter system performed better as compared to the ‘No ventilation’ regime, for all settings and both positions, and for some settings, even better than all the tested mixing ventilation regimes. The use of a mobile HEPA filter system seems a good additional measure when only natural ventilation options are available. Future research should focus on rooms of different sizes or shapes, as this may also play a role in the filter's performance, noise and draught effects.@en

Since the outbreak of COVID-19, wearing a mask, voluntary or obligatory, has led to diverse and numerous designs. Guidelines for minimum requirements include tests for visual inspection, strength, filtration, and breathing resistance, but not for the fit of a mask. The fit of a mask was assessed by testing the outward leakage of exhaled breath based on the visualization of coloured mist exhaled by a manikin head. Fourteen masks were selected based on differences in design, such as type of material, shape (cheek wings vs. none), filter type, and the number of layers. Leakage expressed in mean mist percentages (visualized with a camera), patterns of coloured mist left inside the masks, as well as visual fit of the masks on the manikin head, showed that a loose fit mask results in more leakage. Also, combining quantitative with qualitative assessment proved to be complementary. Future tests should be conducted on a range of users, covering the best fit over time as well breathability, use, and comfort. The use of face masks, whatever their characteristics, seem an adequate strategy to reduce the dispersion of potential ‘infected’ aerosols into the space from people, as opposed to not wearing one.

@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

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

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

For several years indoor comfort is measured in halls of hospitals by architecture students from the Delft University of Technology. Questionnaires and interviews have shows that patients and visitors have very few complaints about the indoor comfort in hospital halls. This, in hindsight, is not so very surprising. Patients and visitors usually come out of the cold into the hallway. A hallway which is at least marginally warmer, a hallway where it does not rain and hallway that is sheltered from the outside wind. Secondly, the indoor comfort is not the main concern of the patients and visitors entering the hospital. The patient’s and visitor’s upcoming consults with the doctors or nurses is much more important. Coming from the consult, patients and visitors always have the choice to immediately leave the hospital if they do not like the indoor comfort. Complaints from staff, however, are very common. Staff personnel usually complain about low temperatures and draught. A reception desk is the main workplace in a hospital hall. A reception desk can be closed, i.e. physically separates the personnel from the environment of the hall. A reception desk can also be open, thus without a physical separation between personnel and patients and visitors. In a hospital, in general, an open reception desk is favoured for a more welcoming atmosphere for patients and visitors. This more open reception desk, however, often causes the personnel to experience low temperatures and draught. From this study it is clear that it is very difficult design a thermally comfortable reception desk in a hospital. The quest for a reception that expresses openness and transparency clearly hinders the design for a comfortable reception desk. On the other hand, the small number of people at the reception desk is in no comparison to the hundreds of staff and patients for which the hospital is also designed. Many solutions to improve thermal comfort at a reception desk are already known. The exact cause of the experienced draught and the best solutions, however, are difficult to determine. Scale models or CFD simulations should be used as a guide for design a reception desk in a hospital or when solving thermal comfort problems. A new cause of draught, people moving past the reception desk, was identified and quantified. As a result, a completely open reception desk inside a large atrium with a lot of people moving past might not be possible without either closing off the reception desk, or increasing the temperature at the reception desk.@en