Philo Bluyssen

• Master of Engineering
• Professor at Delft University of Technology

University students spend a considerable time at study places. The acoustical quality of these study places is one of the indoor environmental qualities (IEQ) that can have an impact on student's health, comfort, and performance. The indoor soundscape approach has been introduced to better understand occupants' sound perception and experience of so...

University students spend a considerable time at study places. The acoustical quality of these study places is one of the indoor environmental qualities (IEQ) that can have an impact on student’s health, comfort, and performance. The indoor soundscape approach has been introduced to better understand occupants’ sound perception and experience of so...

This file is associated with the paper titled "Using mobile air cleaners in school classrooms for aerosol removal: which, where and how", published in journal Indoor and Built Environment. It contains the supplementary information which helps explaining the methods, as well as data that supports the findings of the study. The study investigated the...

Mobile air cleaners (MACs) have been proposed as a supplementary solution to combat the spread of respiratory aerosols in school classrooms. To determine which, where and how to use MACs, seven small- and medium-sized MACs were selected and assessed for different settings and configurations by 1) a decay test for determining the clean air delivery...

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 tech...

If some countries lead by example, standards may increasingly become normalized

The acoustic quality of educational spaces has an important impact on well-being and occupant performance. This study investigates noise perception and hearing ability among primary students in traditional learning environments (TLE) and flexible learning environments (FLE). A survey was conducted in Santiago de Chile, involving 21 teachers and 315...

The acoustic quality of educational spaces has an important impact on well-being and occupant performance. This study investigates noise perception and hearing ability among primary students in traditional learning environments (TLE) and flexible learning environments (FLE). A survey was conducted in Santiago de Chile, involving 21 teachers and 315...

Students are exposed to various environmental stimuli at their home study places. However, different students have different preferences in terms of indoor environmental quality (IEQ) aspects and psychosocial aspects of these places. A previous study on students' preferences of their study places resulted in nine profiles based on their IEQ and psy...

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 CO2 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 measur...

Indoor air quality (IAQ) is an important aspect of maintaining human health and well-being, particularly since people spend most of their time indoors. Carpets, with their large surface area and dense fibre piles, have the potential to significantly impact IAQ by emitting and absorbing volatile organic compounds (VOC) from building materials and hu...

Indoor air quality (IAQ) plays an important role in human health and well-being as people spend most of their time indoors. Among building materials, carpets covering high surface areas and having dense fibres have the potential to impact perceived IAQ. To explore the impact of carpets on perceived IAQ, it was studied whether low-emitting wool carp...

A significant number of young people live in temporary homes, which are designed to fulfil basic needs and provide space for normal activities. However, it is unclear what those basic activities are. Moreover, the indoor environmental quality is often left out of the meaning of home, although activities and objects can affect its experienced qualit...

The COVID-19 pandemic highlighted the importance of indoor air quality (IAQ) and ventilation, which researchers have been warning about for years. During the pandemic, researchers studied several indicators using different approaches to assess IAQ and diverse ventilation systems in indoor spaces. To provide an overview of these indicators and appro...

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 (WHO) about the potential significance of the a...

Research has shown that students differ in their preferences of indoor environmental quality (IEQ) and psychosocial aspects of their study places. Since previous studies have mainly focused on identifying these preferences rather than investigating the different profiles of students, this study aimed at profiling students based on their IEQ and psy...

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 examp...

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) indi...

Interest in having a healthy and well-being environment has increased the awareness to improve indoor air quality (IAQ). Building materials influence the contribution of indoor air pollution, so understanding their behaviour on IAQ is essential. Among building materials, carpets cover surfaces of indoor environments and significantly impact IAQ due...

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 2016-2020 among the first-y...

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 thi...

Despite notable scientific and medical advances, broader political, socioeconomic and behavioural factors continue to undercut the response to the COVID-19 pandemic1,2. Here we convened, as part of this Delphi study, a diverse, multidisciplinary panel of 386 academic, health, non-governmental organization, government and other experts in COVID-19 r...

Despite notable scientific and medical advances, broader political, socioeconomic and behavioural factors continue to undercut the response to the COVID-19 pandemic 1,2 . Here we convened, as part of this Delphi study, a diverse, multidisciplinary panel of 386 academic, health, non-governmental organization, government and other experts in COVID-19...

Despite notable scientific and medical advances, broader political, socioeconomic and behavioural factors continue to undercut the response to the COVID-19 pandemic1,2. Here we convened, as part of this Delphi study, a diverse, multidisciplinary panel of 386 academic, health, non-governmental organization, government and other experts in COVID-19 r...

Despite notable scientific and medical advances, broader political, socioeconomic and behavioural factors continue to undercut the response to the COVID-19 pandemic 1,2 . Here we convened, as part of this Delphi study, a diverse, multidisciplinary panel of 386 academic, health, non-governmental organization, government and other experts in COVID-19...

The question of whether SARS‐CoV‐2 is mainly transmitted by droplets or aerosols has been highly controversial. We sought to explain this controversy through a historical analysis of transmission research in other diseases. For most of human history, the dominant paradigm was that many diseases were carried by the air, often over long distances and...

Airborne transmission has been confirmed as one of three principal ways of SARS-CoV-2 transmission. To reduce the transmission of SARS-CoV-2 indoors, understanding the distribution of respiratory droplets (or aerosols) present in human breath seems therefore important. To study whether the CO 2 concentration can be used as a proxy for the number of...

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 s...

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 env...

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 pref...

The 14th REHVA HVAC World Congress CLIMA2022 challenges advances in technologies for smart energy transition, digitization, circularity, health and well-being in buildings. How can we create circular buildings, fully heated, cooled and powered by renewable energy? How can we design human-centered indoor environments while mastering life-cycle costs...

Since the COVID-19 pandemic, the ventilation of school buildings has attracted considerable attention from the general public and researchers. However, guidance to assess the ventilation performance in classrooms, especially during a pandemic, is still lacking. Therefore, aiming to fill this gap, this study conducted a full-scale laboratory study t...

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 stu...

Potted plants have been reported to uptake VOCs and help “cleaning” the air. This paper presents the results of a laboratory study in which two species of plants (peace lily and Boston fern) and three kinds of substrates (expanded clay, soil, and activated carbon) were tested and monitored on their capacity to deplete formaldehyde and CO2 in a glas...

A recently published simulation-based study has demonstrated the effect of an individually controlled noise-reducing device (ICND) on improving acoustic quality in classrooms. As a follow-up research, this current study aims to develop a real ICND and test it with its target users-- primary school children. The prototype developed in this study loo...

Aim We initially aimed 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 ICU patients. Methods We developed a high-volume air sampler m...

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 base...

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...

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...

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), Pa...

Active plant-based systems are emerging technologies that aim to improve indoor air quality (IAQ). A person’s olfactory system is able to recognize the perceived odor intensity of various materials relatively well, and in many cases, the nose seems to be a better perceiver of pollutants than some equipment is. The aim of this study was to assess th...

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 base...

Background We aimed to study the presence of SARS-CoV-2 in air surrounding infected healthcare workers (HCW) in their homes versus infected patients who were undergoing potential aerosol-generating medical procedures (AGMP). We also studied the effect of different face masks worn bij infected persons on spread of SARS-CoV-2 into the air. Methods W...

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 pr...

People spend around 90% of their time indoors, where they are exposed to various physical stressors, such as unpleasant sounds, odours, temperature, and lighting, which may cause annoyance and discomfort. This literature review is focused on substantial studies that emphasize noise as a physical stressor in the indoor environment. Previous studies...

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 st...

Looking further than COVID-19, some of the key messages: 1. We from now on should include the risk of indoor respiratory infections in our design of buildings and its ventilation. 2. Treat the air quality in a similar way as we are used to for water and food quality. 3. ‘Visualize’ the air quality by displaying monitoring values (e.g. CO2 concentra...

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 acous...

Potted plants have been reported to uptake VOCs and help ‘cleaning’ the air. This paper presents the results of a laboratory study in which two species of plants (Peace Lily and Boston Fern) and three kinds of substrates (expanded clay, soil and activated carbon) were tested and monitored on their capacity to deplete formaldehyde and CO 2 in a glas...

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...

Literature shows that both building systems and occupants’ behaviour contribute to the amount of energy used to create a comfortable indoor environment. To determine possible relationships, energy consumption of nine school buildings was studied in relation to identified building characteristics, self-reported frequency of teachers’ actions, and (p...

The Covid-19 pandemic has caused untold disruption and enhanced mortality rates around the world. Understanding the mechanisms for transmission of SARS-CoV-2 is key to preventing further spread but there is confusion over the meaning of “airborne” whenever transmission is discussed. Scientific ambivalence originates from evidence published many yea...

Comfort and health of outpatient staff is important due to the growing demand of healthcare and its crucial influence on society. Previous studies have mostly focused on the perception of comfort and indicated a large prevalence of building-related symptoms and dissatisfaction with comfort of staff in hospital buildings. Unfortunately, limited info...

During the rapid rise in COVID-19 illnesses and deaths globally, and notwithstanding recommended precautions, questions are voiced about routes of transmission for this pandemic disease. Inhaling small airborne droplets is probable as a third route of infection, in addition to more widely recognized transmission via larger respiratory droplets and...

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 fr...

Well-being in the built environment is a topic that features frequently in building standards and certification schemes, in scholarly articles and in the general press. However, despite this surge in attention, there are still many questions on how to effectively design, measure, and nurture well-being in the built environment. Bringing together ex...

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 activ...

The growing field of indoor health and comfort studies recently shifted from predicting the average comfort and wellbeing of a large population into identifying the needs of individuals in different scenarios. This study aimed to identify different profiles of office workers in the Netherlands who took part in the OFFICAIR study, based on their sel...

It is well known that the demand on hospital staff is increasing and that their comfort and health may be affected negatively by dose and building-related aspects. Comfort and health may differ between hospital departments. However, outpatient areas are understudied. To better understand comfort and health of staff in outpatient areas a survey was...

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 activ...

This paper demonstrates the effectiveness of the TwoStep cluster analysis and the development and first results of a new questionnaire for measuring comfort, health, and energy habits. The justification for the questionnaire is to consolidate questions of six specific domains about occupants' energy consumption patterns, from the behavioural and ps...

Previous studies have shown that next to ‘human smell’, ‘stuffy air’ is one of the discomforts that children report in classrooms. Besides, people’s olfactory system is able to recognize the perceived odour intensity of various materials relatively well and in many cases the nose seems to be a better perceiver of pollutants than some equipment. In...

The acoustic conditions of classrooms received a lot of attention in the last decades because of its important role in school children’s comfort and performance. In a previous field study of 54 classrooms from 21 schools in the Netherlands, more than 85% of the 1145 primary school children reported that they were bothered by noise in the classroom....

Research has shown that, even though the conditions seem to comply with current standards for indoor environmental quality (IEQ) based on single-dose response relationships, staying indoors is not good for our health. In the last three decades, many studies all over the world have been performed to identify and solve health and comfort problems of...

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 scho...

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’, ‘indire...

To better understand home energy consumption, it is important to study the behaviours of occupants in their homes, especially in relation to their comfort needs. A mixed methods study comprising of a questionnaire, interviews, indoor environmental parameters monitoring, and energy consumption readings was performed to group home occupants based on...

A previous field study showed that more than 85% of Dutch children reported they were bothered by noise in the classroom. To investigate the impact of acoustical treatment on children’s phoneme identification, 335 school children (9 to 13 years old) from the previously studied schools were invited to take part in a series of tests in the acoustical...

Indoor environmental quality (IEQ) in classrooms can have an effect on school children’s comfort, health, and performance. In most classrooms, the teacher is the only one who can take actions to change the IEQ. The objective of this study was to identify what teachers usually do to improve IEQ in classrooms and how these actions relate to children’...

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 cont...

Research has shown that staying indoors is not good for our health, even though the conditions seem to comply with current guidelines for indoor environmental quality (IEQ). The growing field of indoor health and comfort studies in schools, offices and homes, shows a discrepancy of current standards with end-users needs. In a previous review it was...

One of the challenges of designing buildings with a good indoor environment is to make it good for everyone. Ideas about requirements vary depending on who is asked; the designer, contractor, owner, investor, and occupant, might all have different ideas about what is the best indoor environment. Usually, the occupant is often the one who is not hea...

The indoor environmental quality, control, layout and appearance may affect comfort and satisfaction of patients, as well as visitors and staff in hospitals. Due to differences in activities, duration of stay and health status, needs of the different groups may vary. In order to design hospitals, which positively support comfort and satisfaction of...

A previous field study showed that more than 85% of Dutch children reported they were bothered by noise in the classroom. To investigate the impact of acoustical treatment on children’s phoneme identification, 335 school children (9 to 13 years old) from the previously studied schools were invited to take part in a series of tests in the acoustical...

Our sensory system (nose) could predict the perceived odour intensity of various materials relatively well and in many cases the nose seems to be a better receptor of pollutants than some equipment. To test this ability with children, odour tests were performed as part of a study performed with 335 primary school children in the air quality test ch...

To investigate whether different colours of the indoor surfaces could have an effect on thermal comfort of children, 335 primary school children were invited to take part in a series of tests conducted in the thermal test chamber of the SenseLab. A three-way factorial randomized design was used to test the effect of three different colours of walls...

To find out whether a surface finishing was preferred under different lighting conditions by school children, in the light test chamber of the SenseLab, 335 children from previous studied schools were asked to assess a desk surface during different light conditions. A two-way randomized design was used to test children’s assessments for six school...

Background: It is well-known that indoor environmental quality (IEQ) in classrooms can have an effect on school children's comfort, health and performance. Unfortunately, information about the school children's perception of IEQ factors in their classrooms is still insufficient. The objective of this study was to better understand school children's...

This paper reviews the state of art of vegetation systems and their effect on the indoor environmental quality (IEQ), based on scientific studies from the past 30 years. Some studies have shown that biophilic workspaces and interaction with plants may change human attitudes, behaviours, improve productivity and the overall well-being. Evapotranspir...

Temporary transformations of vacant buildings could alleviate the shortage of housing for urgent home seekers. However, not much is known about the transformation of buildings into temporary, adequate, and affordable housing. A multidisciplinary literature review covering design, indoor environmental quality, housing, and environmental psychology,...

Background: While the indoor environmental quality of classrooms is a potential issue because it may affect the wellbeing of school children, the relations are still poorly studied. This study aimed to investigate the relations between classroom characteristics and health and comfort of school children. Material and methods: A questionnaire was dis...

Background This paper demonstrates the effectiveness of the TwoStep cluster analysis and the development and first results of a new questionnaire for measuring comfort, health, and energy habits. The justification for the questionnaire is to consolidate into one instrument questions of six specific domains about occupants' energy consumption patter...

Le projet OFFICAIR avait pour objectif de documenter le confort et la qualité de l’air dans les bâtiments de bureaux neufs ou récemment rénovés en Europe. Cet article présente le confort et la santé perçus par les occupants et leurs relations avec les caractéristiques techniques des bâtiments dans les 21 immeubles ayant participé en France. La perc...

In hot and humid climates, for those that can afford it, air conditioning is a standard requirement and designers generally intend their buildings to include some sort of mechanical cooling system to achieve indoor comfort. Consequently, cooling or heating a building requires high-energy demands. The aim of this project was to develop an optional c...

Good indoor environmental quality (IEQ) in classrooms is an essential requirement to ensure children's comfort and learning performance. However, although in most studies the current situation of the IEQ in classrooms has been investigated, few or no studies have been focused on the way to ameliorate it. Recently, some researchers managed to utiliz...

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 subjec...

This article seeks to present an optional cooling tool based on the integration of a Living Wall System (LWS), a fan and a dehumidification process (desiccant) to reduce the use of an HVAC system. This study showed that it is possible to use the evapotranspiration of plants for air-cooling and humidity control.

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...

The research project was initiated in 1993 by the Commission of European Communities. Its general objective was to improve the knowledge on indoor air quality in relationship with energy consumption in large office buildings. Seven countries of the European Community and three EFTA countries participate to this project. To gain knowledge, at least...

From previous and recent studies, it is clear that an indoor environment of a school may affect the health, comfort and performance of schoolchildren. Besides the occupants and their activities, the windows and the outdoor environment and the type of ventilation system, the interior (furnishing incl. flooring materials) is an important contributor...