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P.M. Bluyssen
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148 records found
1
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Journal article
(2026)
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Clarize de Korne, Kim Romijnders, Philomena Bluyssen, Daniel Bonn, Er Ding, Antoine Gaillard, Esmée Janssen, Anne Rittscher-Fogg, Inge Wouters, Patricia Bruijning-Verhagen
During respiratory virus outbreaks, mobile air cleaning devices (MACs) are increasingly considered in schools as a preventive measure. However, evidence on their real-world performance, feasibility, and potential health impact in classroom settings remains limited. This pilot study was conducted to inform the design of a future large-scale trial by providing a comprehensive evaluation of MACs in primary school classrooms, integrating technical performance (including indoor air quality and airborne microbial assessments), user-perceived feasibility, and the suitability of illness-related absenteeism as a potential pragmatic outcome measure for infection rates. A randomized cross-over study was conducted in five Dutch primary schools, involving 45 classrooms equipped with MACs. Each classroom alternated between three-week periods with the devices switched on and off. Indoor air quality was assessed in a subset of classrooms using sensors for CO₂ and particulate matter, while airborne microbial contamination was monitored through air dust sampling and molecular testing. Illness-related absenteeism was evaluated as a potential outcome measure. MACs effectively halved indoor particulate matter levels, confirming their technical performance. This reduction did not translate into a measurable reduction in airborne microbial contamination, although such contamination was successfully detected. Feasibility assessment revealed low acceptability among teachers due to reduced environmental comfort. Absenteeism was identified as a suitable proxy for infectious diseases, with simulations indicating that a future cluster-randomized trial would require 40–70 schools to detect a 20–25% reduction in absenteeism.
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During respiratory virus outbreaks, mobile air cleaning devices (MACs) are increasingly considered in schools as a preventive measure. However, evidence on their real-world performance, feasibility, and potential health impact in classroom settings remains limited. This pilot study was conducted to inform the design of a future large-scale trial by providing a comprehensive evaluation of MACs in primary school classrooms, integrating technical performance (including indoor air quality and airborne microbial assessments), user-perceived feasibility, and the suitability of illness-related absenteeism as a potential pragmatic outcome measure for infection rates. A randomized cross-over study was conducted in five Dutch primary schools, involving 45 classrooms equipped with MACs. Each classroom alternated between three-week periods with the devices switched on and off. Indoor air quality was assessed in a subset of classrooms using sensors for CO₂ and particulate matter, while airborne microbial contamination was monitored through air dust sampling and molecular testing. Illness-related absenteeism was evaluated as a potential outcome measure. MACs effectively halved indoor particulate matter levels, confirming their technical performance. This reduction did not translate into a measurable reduction in airborne microbial contamination, although such contamination was successfully detected. Feasibility assessment revealed low acceptability among teachers due to reduced environmental comfort. Absenteeism was identified as a suitable proxy for infectious diseases, with simulations indicating that a future cluster-randomized trial would require 40–70 schools to detect a 20–25% reduction in absenteeism.
Journal article
(2026)
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Robert S. McLeod, Ulla Haverinen-Shaughnessy, Pawel Wargocki, Marcel Loomans, Tunga Salthammer, Twan van Hooff, Malcolm J. Cook, Philomena M. Bluyssen, Atze Boerstra, More authors...
Research about the importance of ventilation and indoor air quality in schools has attracted scientific attention for several decades. Multiple studies have identified associations between outdoor air ventilation rates, indoor air quality, and the health, well-being, and cognitive performance of students; the precise causes of which are not fully understood. More recently schools were identified as a key node of transmission in the COVID-19 pandemic. This realisation fundamentally changed the discourse around school ventilation across Europe. Despite this awareness, and the annual burden of airborne diseases (including influenza, RSV, and others) as well as the increased likelihood of further pandemics, very little progress has been made in terms of practical measures or policy changes. This paper examines ten key questions regarding the future of ventilation and indoor air quality in European schools through the eyes of twelve European experts. By examining these multi-faceted issues in a holistic way, the work sets out to draw clear conclusions about what is needed to improve widespread air quality problems and defects in school ventilation practices across Europe. Despite inconclusive findings in some areas, the authors argue that there is sufficient evidence to act decisively to reduce the risk of short and long-term harms and to mitigate significant health inequalities.
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Research about the importance of ventilation and indoor air quality in schools has attracted scientific attention for several decades. Multiple studies have identified associations between outdoor air ventilation rates, indoor air quality, and the health, well-being, and cognitive performance of students; the precise causes of which are not fully understood. More recently schools were identified as a key node of transmission in the COVID-19 pandemic. This realisation fundamentally changed the discourse around school ventilation across Europe. Despite this awareness, and the annual burden of airborne diseases (including influenza, RSV, and others) as well as the increased likelihood of further pandemics, very little progress has been made in terms of practical measures or policy changes. This paper examines ten key questions regarding the future of ventilation and indoor air quality in European schools through the eyes of twelve European experts. By examining these multi-faceted issues in a holistic way, the work sets out to draw clear conclusions about what is needed to improve widespread air quality problems and defects in school ventilation practices across Europe. Despite inconclusive findings in some areas, the authors argue that there is sufficient evidence to act decisively to reduce the risk of short and long-term harms and to mitigate significant health inequalities.
(Dis)comfort and Health-induced Stress
The need for unravelling their effects
This article is a summary of the article presented at the IEQ conference in Montreal [1], in which the question “What is needed to determine other indicators that can help to prevent long-term health effects?” is answered in four steps.
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This article is a summary of the article presented at the IEQ conference in Montreal [1], in which the question “What is needed to determine other indicators that can help to prevent long-term health effects?” is answered in four steps.
Research has shown that even though the indoor environmental conditions seem to comply with current standards and guidelines and those conditions seem 'comfortable' enough, staying indoors is not good for our health. Reasons for this discrepancy might be the fact that these guidelines are mainly based on single-dose response relationships (effect modelling using dose-related indicators) for the physical stressors (odour, light, sound, and temperature) determined for an average adult person; aimed at preventing short-term discomfort, not long-term health effects, ignoring situation-related aspects, ignoring different preferences and needs of occupants. In four steps, the question "What is needed to determine other indicators that can help to prevent long-term health effects?" is answered. In step 1, a more comprehensive research model than the single dose-response model is introduced. Step 2 is concerned with the validation of that model based on a series of field studies. Step 3 addresses the need for methods (and indicators) that enable us to study interactions occurring at human level (perceptual and physiological) induced by indoor environmental stressors resulting in both short-term and long-term (integrated) effects. Finally, in step 4, it is emphasized that to determine indicators that can be used to predict long-term health effects from 'short-term' perceptual assessments and/or physiological measurement requires understanding of how our body copes with stressors that trigger the (dis) comfort-induced mechanisms and the health-induced mechanisms.
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Research has shown that even though the indoor environmental conditions seem to comply with current standards and guidelines and those conditions seem 'comfortable' enough, staying indoors is not good for our health. Reasons for this discrepancy might be the fact that these guidelines are mainly based on single-dose response relationships (effect modelling using dose-related indicators) for the physical stressors (odour, light, sound, and temperature) determined for an average adult person; aimed at preventing short-term discomfort, not long-term health effects, ignoring situation-related aspects, ignoring different preferences and needs of occupants. In four steps, the question "What is needed to determine other indicators that can help to prevent long-term health effects?" is answered. In step 1, a more comprehensive research model than the single dose-response model is introduced. Step 2 is concerned with the validation of that model based on a series of field studies. Step 3 addresses the need for methods (and indicators) that enable us to study interactions occurring at human level (perceptual and physiological) induced by indoor environmental stressors resulting in both short-term and long-term (integrated) effects. Finally, in step 4, it is emphasized that to determine indicators that can be used to predict long-term health effects from 'short-term' perceptual assessments and/or physiological measurement requires understanding of how our body copes with stressors that trigger the (dis) comfort-induced mechanisms and the health-induced mechanisms.
Research has shown that even though the indoor environmental conditions seem to comply with current standards and guidelines and those conditions seem ‘comfortable’ enough, staying indoors is not good for our health. Reasons for this discrepancy might be the fact that these guidelines (such as ventilation rate, lighting level, and temperature ranges) are mainly based on single-dose response relationships (effect modelling using dose-related indicators) for the physical stressors (e.g. odour, light, sound, and temperature) determined for an average adult person. They are aimed at preventing short-term discomfort rather than long-term negative health effects, ignoring situation-related aspects and different preferences and needs of occupants. A more comprehensive model, accounting for integrated effects of all stressors, and different preferences and needs of occupants in different scenarios and situations, based on situation modelling making use of building and occupant-related indicators, is introduced and partly validated in a series of field studies in different scenarios. Based on the outcome of these field studies and insights from other studies, the methods, indicators and in particular the human model are discussed. Research directions to go beyond the mainly comfort-based dose-related indicators in our IEQ (indoor environmental quality)-guidelines are proposed.
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Research has shown that even though the indoor environmental conditions seem to comply with current standards and guidelines and those conditions seem ‘comfortable’ enough, staying indoors is not good for our health. Reasons for this discrepancy might be the fact that these guidelines (such as ventilation rate, lighting level, and temperature ranges) are mainly based on single-dose response relationships (effect modelling using dose-related indicators) for the physical stressors (e.g. odour, light, sound, and temperature) determined for an average adult person. They are aimed at preventing short-term discomfort rather than long-term negative health effects, ignoring situation-related aspects and different preferences and needs of occupants. A more comprehensive model, accounting for integrated effects of all stressors, and different preferences and needs of occupants in different scenarios and situations, based on situation modelling making use of building and occupant-related indicators, is introduced and partly validated in a series of field studies in different scenarios. Based on the outcome of these field studies and insights from other studies, the methods, indicators and in particular the human model are discussed. Research directions to go beyond the mainly comfort-based dose-related indicators in our IEQ (indoor environmental quality)-guidelines are proposed.
While the worst COVID-19 pandemic is past us and everything has almost returned to normal, we should act on the lessons learned and prepare for a future pandemic. Public places of large social gatherings like cafes, bars, and restaurants might be the most vulnerable indoor environments because the occupants face each other in combination with poor ventilation. However, little research has been done to study such a social setting. As an initial experimental study, a respiring manikin setup is developed to mimic face-to-face conversations between two occupants. This setup can mimic and visualize speech-like particle-laden flow in different environmental conditions. It has the potential to quantify the illuminated flow field for correlation with numerical simulations and be used with infectious viruses for virology studies in the context of airborne transmission.
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While the worst COVID-19 pandemic is past us and everything has almost returned to normal, we should act on the lessons learned and prepare for a future pandemic. Public places of large social gatherings like cafes, bars, and restaurants might be the most vulnerable indoor environments because the occupants face each other in combination with poor ventilation. However, little research has been done to study such a social setting. As an initial experimental study, a respiring manikin setup is developed to mimic face-to-face conversations between two occupants. This setup can mimic and visualize speech-like particle-laden flow in different environmental conditions. It has the potential to quantify the illuminated flow field for correlation with numerical simulations and be used with infectious viruses for virology studies in the context of airborne transmission.
De via de lucht overgedragen infectieuze respiratoire deeltjes (IRDs), ook wel aerosolen genoemd, zijn de primaire route van overdracht voor respiratoire infectieuze ziektes zoals COVID-19 [1]. Klaslokalen hebben een verhoogd risico op besmetting vanwege de lange en hoge bezetting [2]. Deze overdracht kan dichtbij plaatsvinden, maar ook verder weg. Tijdens een door ZonMw gefinancierd veldonderzoek naar de verspreiding van het SARS-CoV-2 virus en de binnenmilieucondities in klaslokalen [3], bleek zowel de ventilatie als de temperatuur onvoldoende te zijn. Scholen hebben behoefte aan beheersbare maar ook betaalbare oplossingen. Mobiele luchtreinigers (MLRs) zijn een mogelijke (betaalbare) oplossing om overdracht van IRDs op lange afstand te verminderen. In opdracht van het Ministerie van Onderwijs Cultuur en Wetenschap werd daarom een vervolgonderzoek gestart met de vraag: zouden mobiele luchtreinigers in een toekomstige pandemie de situatie kunnen verbeteren?
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De via de lucht overgedragen infectieuze respiratoire deeltjes (IRDs), ook wel aerosolen genoemd, zijn de primaire route van overdracht voor respiratoire infectieuze ziektes zoals COVID-19 [1]. Klaslokalen hebben een verhoogd risico op besmetting vanwege de lange en hoge bezetting [2]. Deze overdracht kan dichtbij plaatsvinden, maar ook verder weg. Tijdens een door ZonMw gefinancierd veldonderzoek naar de verspreiding van het SARS-CoV-2 virus en de binnenmilieucondities in klaslokalen [3], bleek zowel de ventilatie als de temperatuur onvoldoende te zijn. Scholen hebben behoefte aan beheersbare maar ook betaalbare oplossingen. Mobiele luchtreinigers (MLRs) zijn een mogelijke (betaalbare) oplossing om overdracht van IRDs op lange afstand te verminderen. In opdracht van het Ministerie van Onderwijs Cultuur en Wetenschap werd daarom een vervolgonderzoek gestart met de vraag: zouden mobiele luchtreinigers in een toekomstige pandemie de situatie kunnen verbeteren?
How different sounds affect bodily responses and the perception of odour, light and temperature
A pilot study on interaction effects within IEQ domains
During perception with our senses, interactions of different environmental stressors at brain level might occur. Previous studies have shown cross-modal effects between sound and odour. To test these effects of different sounds and levels of sounds on the perception of sound, temperature, odour, and light, as well as a number of physiological indicators, sixteen students were exposed to four different sounds (two indoor: mechanical ventilation & people talking; two outdoor: quiet rural area & city centre area) and two different sound pressure levels per sound, while sitting in a semi-lab environment. Bodily responses were sampled with wearable devices. Heart rate and breathing rate were monitored using a smart watch; EEG measurements were performed to assess their attention and mental relaxation levels; Acceptability and experience were assessed through a questionnaire to assess their comfort perception. Additionally, each student took a hearing test. The outcome showed when the traffic sound level increased, the students perceived the air as more smelly and less acceptable. The other sounds did not show any cross-modal effect. Moreover, heart rate and breathing rate significantly differed during the different tests, confirming that these two indicators can help to explain the physiological effect of noise as a stressor.
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During perception with our senses, interactions of different environmental stressors at brain level might occur. Previous studies have shown cross-modal effects between sound and odour. To test these effects of different sounds and levels of sounds on the perception of sound, temperature, odour, and light, as well as a number of physiological indicators, sixteen students were exposed to four different sounds (two indoor: mechanical ventilation & people talking; two outdoor: quiet rural area & city centre area) and two different sound pressure levels per sound, while sitting in a semi-lab environment. Bodily responses were sampled with wearable devices. Heart rate and breathing rate were monitored using a smart watch; EEG measurements were performed to assess their attention and mental relaxation levels; Acceptability and experience were assessed through a questionnaire to assess their comfort perception. Additionally, each student took a hearing test. The outcome showed when the traffic sound level increased, the students perceived the air as more smelly and less acceptable. The other sounds did not show any cross-modal effect. Moreover, heart rate and breathing rate significantly differed during the different tests, confirming that these two indicators can help to explain the physiological effect of noise as a stressor.
During perception with our senses interactions of different environmental stressors (olfactory, auditory, visual and thermal stimuli) at brain level might occur. To test these cross-modal effects, a three-way factorial design was applied. In total, 60 students across six groups were each exposed to three randomized combinations of different environmental conditions: three sound conditions, three lighting conditions, and two ventilation modes, while sitting in a semi-lab environment. Heart rate and respiration rate were monitored using a smart watch; acceptability and experience were collected through a questionnaire to assess subjects' comfort perception. Results showed no statistical differences between the two ventilation modes and no effect of light type on the physiological indicators. A trend towards an interaction effect was found for sound∗light on the acceptability of odour (p=0.076) and the perceived level of sound (p=0.055). For future studies, it is therefore important to first identify physiological indicators that can be affected by all the independent factors studied.
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During perception with our senses interactions of different environmental stressors (olfactory, auditory, visual and thermal stimuli) at brain level might occur. To test these cross-modal effects, a three-way factorial design was applied. In total, 60 students across six groups were each exposed to three randomized combinations of different environmental conditions: three sound conditions, three lighting conditions, and two ventilation modes, while sitting in a semi-lab environment. Heart rate and respiration rate were monitored using a smart watch; acceptability and experience were collected through a questionnaire to assess subjects' comfort perception. Results showed no statistical differences between the two ventilation modes and no effect of light type on the physiological indicators. A trend towards an interaction effect was found for sound∗light on the acceptability of odour (p=0.076) and the perceived level of sound (p=0.055). For future studies, it is therefore important to first identify physiological indicators that can be affected by all the independent factors studied.
In response to the WHO and UN's call to ensure children's right to breathe "clean"air and the challenges posed by the COVID-19 pandemic on maintaining healthy indoor air quality (IAQ), a holistic research was conducted to explore ventilation and air cleaning strategies to control the spread of infectious respiratory particles (IRPs) in school classrooms. The study follows four key steps: (1) a literature review bridging school ventilation regimes, IRP transmission, and advanced ventilation systems; (2) a field study to evaluate real-world ventilation and thermal conditions during the pandemic; (3) an experimental investigation of performance of mobile air cleaners (MACs) followed by an in-situ validation; and (4) a combined experimental and computational study to assess personalized air cleaners (PACs) as localized exhaust for IRP removal. Findings reveal that most classrooms rely on natural ventilation, often failing to meet IAQ standards, especially when fully occupied. With windows and doors kept open, ventilation rates remained inconsistent, and thermal conditions were unsatisfactory. Hence, more controllable ventilation and air cleaning approaches are needed. MACs, when appropriately selected and positioned, offer effective protection against long-range IRP transmission at room scale, while PACs are effective at mitigating localized, short-range IRP exposure, improving IAQ at an individual level.
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In response to the WHO and UN's call to ensure children's right to breathe "clean"air and the challenges posed by the COVID-19 pandemic on maintaining healthy indoor air quality (IAQ), a holistic research was conducted to explore ventilation and air cleaning strategies to control the spread of infectious respiratory particles (IRPs) in school classrooms. The study follows four key steps: (1) a literature review bridging school ventilation regimes, IRP transmission, and advanced ventilation systems; (2) a field study to evaluate real-world ventilation and thermal conditions during the pandemic; (3) an experimental investigation of performance of mobile air cleaners (MACs) followed by an in-situ validation; and (4) a combined experimental and computational study to assess personalized air cleaners (PACs) as localized exhaust for IRP removal. Findings reveal that most classrooms rely on natural ventilation, often failing to meet IAQ standards, especially when fully occupied. With windows and doors kept open, ventilation rates remained inconsistent, and thermal conditions were unsatisfactory. Hence, more controllable ventilation and air cleaning approaches are needed. MACs, when appropriately selected and positioned, offer effective protection against long-range IRP transmission at room scale, while PACs are effective at mitigating localized, short-range IRP exposure, improving IAQ at an individual level.
As mandatory masking and social distancing measures decrease post-COVID-19, the risk of airborne pathogen transmission in crowded indoor spaces remains a significant public health concern. The pandemic highlighted the critical role of indoor air quality and ventilation in mitigating the spread of infectious diseases, underscoring the urgent need to improve our understanding and prediction of indoor airflow to minimise airborne transmission. In this review, studies on airborne transmission in indoor settings were systematically reviewed to identify research gaps and recommend changes in approach. The analysis is categorised into indoor airflow, dynamics of infectious respiratory particles (IRPs), and investigation methodologies. Findings reveal that almost 40% of the reviewed literature does not specify the type of indoor setting, with only 3% focusing on restaurant environments. Additionally, indoor air conditions are typically assumed to be constant, and respiratory activities are often limited to coughing and breathing. The review identifies the challenge of replicating the complex behaviour of IRPs in experiments and the computational expense of predicting turbulent indoor flows. Recommendations for future research include: i) focusing on social settings like restaurants, ii) considering varying air temperatures and humidity, iii) examining speech-related respiratory flows, and iv) employing visual and accurate tools to investigate particle-laden airflow. These insights aim to enhance public health guidelines and building designs to reduce the risk of airborne diseases.
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As mandatory masking and social distancing measures decrease post-COVID-19, the risk of airborne pathogen transmission in crowded indoor spaces remains a significant public health concern. The pandemic highlighted the critical role of indoor air quality and ventilation in mitigating the spread of infectious diseases, underscoring the urgent need to improve our understanding and prediction of indoor airflow to minimise airborne transmission. In this review, studies on airborne transmission in indoor settings were systematically reviewed to identify research gaps and recommend changes in approach. The analysis is categorised into indoor airflow, dynamics of infectious respiratory particles (IRPs), and investigation methodologies. Findings reveal that almost 40% of the reviewed literature does not specify the type of indoor setting, with only 3% focusing on restaurant environments. Additionally, indoor air conditions are typically assumed to be constant, and respiratory activities are often limited to coughing and breathing. The review identifies the challenge of replicating the complex behaviour of IRPs in experiments and the computational expense of predicting turbulent indoor flows. Recommendations for future research include: i) focusing on social settings like restaurants, ii) considering varying air temperatures and humidity, iii) examining speech-related respiratory flows, and iv) employing visual and accurate tools to investigate particle-laden airflow. These insights aim to enhance public health guidelines and building designs to reduce the risk of airborne diseases.
Wat je moet weten over klimaatinstallaties
Het hoe en waarom van klimaatinstallaties in een notendop
Airconditioning heeft een negatief imago: het zou ons minder tolerant maken voor temperatuurveranderingen; produceert achtergrondlawaai; zorgt voor tocht; kan de lucht verontreinigen; is moeilijk te bedienen; heeft onderhoud nodig; en gebruikt veel energie. Het is echter in principe economisch mogelijk om installaties te maken en in stand te houden die zowel energetisch verantwoord zijn als een gezond en comfortabel klimaat realiseren. De aanbevelingen en informatie in deze gids zijn bruikbaar voor architecten, installateurs, adviseurs, en voor personen die verantwoordelijk zijn voor het onderhoud van een klimaatinstallatie in een niet-industriële omgeving: bijvoorbeeld je eigen woonomgeving, op school of in een kantoorsituatie!
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Airconditioning heeft een negatief imago: het zou ons minder tolerant maken voor temperatuurveranderingen; produceert achtergrondlawaai; zorgt voor tocht; kan de lucht verontreinigen; is moeilijk te bedienen; heeft onderhoud nodig; en gebruikt veel energie. Het is echter in principe economisch mogelijk om installaties te maken en in stand te houden die zowel energetisch verantwoord zijn als een gezond en comfortabel klimaat realiseren. De aanbevelingen en informatie in deze gids zijn bruikbaar voor architecten, installateurs, adviseurs, en voor personen die verantwoordelijk zijn voor het onderhoud van een klimaatinstallatie in een niet-industriële omgeving: bijvoorbeeld je eigen woonomgeving, op school of in een kantoorsituatie!
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 sounds in relation to the environment. This study aims to explore the indoor soundscapes of home study places of these students by conducting semi-structured interviews with 23 university students with different profiles. For qualitative analysis, open coding was used. Sub-categories, based on the codes, and categories were created and assigned to the soundscape themes that are defined in ISO 12913-1. An affinity diagram consisting of the themes, categories, and sub-categories was initially developed. Then, it was validated through two workshops with participants. The results showed that the interpretation of the sound environment, responses, and outcomes differed among the students. In a previous study, 451 students were clustered in 5 clusters with similar acoustical preferences (profiles). Therefore, it is recommended to consider making the indoor soundscape approach applicable for different profiles of occupants.
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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 sounds in relation to the environment. This study aims to explore the indoor soundscapes of home study places of these students by conducting semi-structured interviews with 23 university students with different profiles. For qualitative analysis, open coding was used. Sub-categories, based on the codes, and categories were created and assigned to the soundscape themes that are defined in ISO 12913-1. An affinity diagram consisting of the themes, categories, and sub-categories was initially developed. Then, it was validated through two workshops with participants. The results showed that the interpretation of the sound environment, responses, and outcomes differed among the students. In a previous study, 451 students were clustered in 5 clusters with similar acoustical preferences (profiles). Therefore, it is recommended to consider making the indoor soundscape approach applicable for different profiles of occupants.
Mandating indoor air quality for public buildings
If some countries lead by example, standards may increasingly become normalized
Journal article
(2024)
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Lidia Morawska, Joseph Allen, William Bahnfleth, Belinda Bennett, Philomena M. Bluyssen, Atze Boerstra, Giorgio Buonanno, Junji Cao, Stephanie J. Dancer, More authors...
People living in urban and industrialized societies, which are expanding globally, spend more than 90% of their time in the indoor environment, breathing indoor air (IA). Despite decades of research and advocacy, most countries do not have legislated indoor air quality (IAQ) performance standards for public spaces that address concentration levels of IA pollutants (1). Few building codes address operation, maintenance, and retrofitting, and most do not focus on airborne disease transmission. But the COVID-19 pandemic has made all levels of society, from community members to decision-makers, realize the importance of IAQ for human health, wellbeing, productivity, and learning. We propose that IAQ standards be mandatory for public spaces. Although enforcement of IAQ performance standards in homes is not possible, homes must be designed and equipped so that they could meet the standards.
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People living in urban and industrialized societies, which are expanding globally, spend more than 90% of their time in the indoor environment, breathing indoor air (IA). Despite decades of research and advocacy, most countries do not have legislated indoor air quality (IAQ) performance standards for public spaces that address concentration levels of IA pollutants (1). Few building codes address operation, maintenance, and retrofitting, and most do not focus on airborne disease transmission. But the COVID-19 pandemic has made all levels of society, from community members to decision-makers, realize the importance of IAQ for human health, wellbeing, productivity, and learning. We propose that IAQ standards be mandatory for public spaces. Although enforcement of IAQ performance standards in homes is not possible, homes must be designed and equipped so that they could meet the standards.
Previous studies have shown that sound influences students both physiologically and perceptually. However, most of these studies focussed on the effects of sounds at group-level, ignoring individual differences. Therefore, we investigated which indicators can be used to identify differences in bodily responses and perceptual assessments of each individual when exposed to four different sounds. First, based on an audiometric test, the hearing acuity of 15 students (from five different profiles based on their acoustical preferences and needs) was measured. Then, two sound exposure experiments were conducted in the SenseLab: direct sound exposure using earbuds in a laboratory setting, and indirect sound exposure with speakers in a real room setting. During each experiment, the attention level (AL), mental relaxation level (MRL), heart rate (HR), and respiration rate (RR) were measured with wearable devices, and students made perceptual assessments of each condition. The percentage of change normalised the four bodily response measurements among students. Based on correlation analysis and t-tests, bodily responses, and perceptual assessments across experiments were compared, at group-level and individual-level. Six students, who suffered from mild hearing loss in low-frequency sounds, showed bodily responses such as increased HR during exposure to low-frequency sound conditions. Perceptual assessments of different sound types during both lab experiments substantiated the acoustical preferences of the students from the five profiles. Bodily responses showed no strong nor significant correlations with perceptual assessments during the direct sound exposure experiments. Differences in bodily responses and perceptual assessments between the two experiments and between group-level and individual-level were observed in AL. It is concluded that hearing acuity and type of sound (sound frequencies) are key indicators for identifying differences in bodily responses (such as HR and RR) and perceptual assessment. For future research, it is crucial to consider incorporating audiometric tests, bodily responses such as HR and RR, and perceptual assessments in this type of investigations.
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Previous studies have shown that sound influences students both physiologically and perceptually. However, most of these studies focussed on the effects of sounds at group-level, ignoring individual differences. Therefore, we investigated which indicators can be used to identify differences in bodily responses and perceptual assessments of each individual when exposed to four different sounds. First, based on an audiometric test, the hearing acuity of 15 students (from five different profiles based on their acoustical preferences and needs) was measured. Then, two sound exposure experiments were conducted in the SenseLab: direct sound exposure using earbuds in a laboratory setting, and indirect sound exposure with speakers in a real room setting. During each experiment, the attention level (AL), mental relaxation level (MRL), heart rate (HR), and respiration rate (RR) were measured with wearable devices, and students made perceptual assessments of each condition. The percentage of change normalised the four bodily response measurements among students. Based on correlation analysis and t-tests, bodily responses, and perceptual assessments across experiments were compared, at group-level and individual-level. Six students, who suffered from mild hearing loss in low-frequency sounds, showed bodily responses such as increased HR during exposure to low-frequency sound conditions. Perceptual assessments of different sound types during both lab experiments substantiated the acoustical preferences of the students from the five profiles. Bodily responses showed no strong nor significant correlations with perceptual assessments during the direct sound exposure experiments. Differences in bodily responses and perceptual assessments between the two experiments and between group-level and individual-level were observed in AL. It is concluded that hearing acuity and type of sound (sound frequencies) are key indicators for identifying differences in bodily responses (such as HR and RR) and perceptual assessment. For future research, it is crucial to consider incorporating audiometric tests, bodily responses such as HR and RR, and perceptual assessments in this type of investigations.
Web publication
(2024)
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Lars Ekberg, Pawel Wargocki, Ida Bryn, Andrei Vladimir Litiu, John Rune Nielsen, P.M. Bluyssen
In the realm of environmental, social, and governance (ESG) reporting, the spotlight typically focuses on factors like carbon emissions, social responsibility, and corporate governance. [...]
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In the realm of environmental, social, and governance (ESG) reporting, the spotlight typically focuses on factors like carbon emissions, social responsibility, and corporate governance. [...]
Thermal and indoor air quality in dwellings in Europe during summer
A literature review on findings from empirical studies
Conference paper
(2024)
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A.M. Eijkelenboom, M.J. Tenpierik, M. Ottele, M.R. Vogt, O. Isabella, R. Cavallo, P.M. Bluyssen
Changing outdoor conditions, i.e. higher outdoor air temperature, higher occurrence of heatwaves and outdoor air pollution, increase the risk of overheating and accumulation of air pollution in homes. Previous studies showed that high indoor air temperatures and air pollution affect occupants’ health, resulting in cardio-vascular and respiratory diseases, eyes and skin symptoms, and mortality. Measures to increase energy efficiency of renovated and newly built homes can further increase health risks during extreme weather events and can increase the outdoor temperature. Moreover, the rise of the outdoor air temperature in Europe is higher than the global average.
Therefore, understanding of the extent of current overheating and indoor air pollution and of the contributing factors is necessary to identify the required adaptability of dwellings in Europe to changing outdoor conditions. The objective of this study is to systematically review consequences of changing outdoor conditions, building characteristics, and technology on the indoor environment and occupants’ health in homes in European countries during summer.
This review focuses on empirical studies, as these enable to capture real world interactions of occupants and buildings in relation to outdoor conditions. Varying outdoor conditions, building-, and occupant-related aspects in different European climate zones are discussed. Main findings are that overheating already occurs in normal summers in temperate and northern European countries, while variation in overheating is related to occupants’ adaptative behaviour and building-related aspects. Based on the review, it is suggested to investigate adaptability of dwellings to changing occupants’ needs, new energy efficient technologies, and changing outdoor conditions. ...
Therefore, understanding of the extent of current overheating and indoor air pollution and of the contributing factors is necessary to identify the required adaptability of dwellings in Europe to changing outdoor conditions. The objective of this study is to systematically review consequences of changing outdoor conditions, building characteristics, and technology on the indoor environment and occupants’ health in homes in European countries during summer.
This review focuses on empirical studies, as these enable to capture real world interactions of occupants and buildings in relation to outdoor conditions. Varying outdoor conditions, building-, and occupant-related aspects in different European climate zones are discussed. Main findings are that overheating already occurs in normal summers in temperate and northern European countries, while variation in overheating is related to occupants’ adaptative behaviour and building-related aspects. Based on the review, it is suggested to investigate adaptability of dwellings to changing occupants’ needs, new energy efficient technologies, and changing outdoor conditions. ...
Changing outdoor conditions, i.e. higher outdoor air temperature, higher occurrence of heatwaves and outdoor air pollution, increase the risk of overheating and accumulation of air pollution in homes. Previous studies showed that high indoor air temperatures and air pollution affect occupants’ health, resulting in cardio-vascular and respiratory diseases, eyes and skin symptoms, and mortality. Measures to increase energy efficiency of renovated and newly built homes can further increase health risks during extreme weather events and can increase the outdoor temperature. Moreover, the rise of the outdoor air temperature in Europe is higher than the global average.
Therefore, understanding of the extent of current overheating and indoor air pollution and of the contributing factors is necessary to identify the required adaptability of dwellings in Europe to changing outdoor conditions. The objective of this study is to systematically review consequences of changing outdoor conditions, building characteristics, and technology on the indoor environment and occupants’ health in homes in European countries during summer.
This review focuses on empirical studies, as these enable to capture real world interactions of occupants and buildings in relation to outdoor conditions. Varying outdoor conditions, building-, and occupant-related aspects in different European climate zones are discussed. Main findings are that overheating already occurs in normal summers in temperate and northern European countries, while variation in overheating is related to occupants’ adaptative behaviour and building-related aspects. Based on the review, it is suggested to investigate adaptability of dwellings to changing occupants’ needs, new energy efficient technologies, and changing outdoor conditions.
Therefore, understanding of the extent of current overheating and indoor air pollution and of the contributing factors is necessary to identify the required adaptability of dwellings in Europe to changing outdoor conditions. The objective of this study is to systematically review consequences of changing outdoor conditions, building characteristics, and technology on the indoor environment and occupants’ health in homes in European countries during summer.
This review focuses on empirical studies, as these enable to capture real world interactions of occupants and buildings in relation to outdoor conditions. Varying outdoor conditions, building-, and occupant-related aspects in different European climate zones are discussed. Main findings are that overheating already occurs in normal summers in temperate and northern European countries, while variation in overheating is related to occupants’ adaptative behaviour and building-related aspects. Based on the review, it is suggested to investigate adaptability of dwellings to changing occupants’ needs, new energy efficient technologies, and changing outdoor conditions.
Understanding students' preferences of their study place, in particular acoustical and psychosocial preferences, is important to students' health and comfort. This study aimed to identify clusters of students with similar acoustical and psychosocial preferences, and to identify reasons for certain preferences of students in each cluster. A mixed-methods approach was applied, consisting of a questionnaire, which was completed by 451 bachelor students, and a field study conducted with 23 students from the same sample. The questionnaire data included among others acoustical and psychosocial preferences scores, while the field study data comprised interview transcripts, building checklists, and sound pressure level measurements. The questionnaire data were analysed using TwoStep cluster analysis to identify clusters of students based on their acoustical and psychosocial preferences. This produced five clusters of students that significantly differed in 14 variables, including preferences and perception of indoor environmental quality (e.g., noise from outside). Then, the field study data were analysed and categorised based on the five clusters of the students. The outcome explained the aspects associated with the acoustical preferences of students in each cluster. Building-related indicators such as the location of the building were found as an aspect that could affect the student's acoustical preferences. This study provides insight into the profiles of students based on their acoustical and psychosocial preferences, which are important for their health and comfort at their study places.
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Understanding students' preferences of their study place, in particular acoustical and psychosocial preferences, is important to students' health and comfort. This study aimed to identify clusters of students with similar acoustical and psychosocial preferences, and to identify reasons for certain preferences of students in each cluster. A mixed-methods approach was applied, consisting of a questionnaire, which was completed by 451 bachelor students, and a field study conducted with 23 students from the same sample. The questionnaire data included among others acoustical and psychosocial preferences scores, while the field study data comprised interview transcripts, building checklists, and sound pressure level measurements. The questionnaire data were analysed using TwoStep cluster analysis to identify clusters of students based on their acoustical and psychosocial preferences. This produced five clusters of students that significantly differed in 14 variables, including preferences and perception of indoor environmental quality (e.g., noise from outside). Then, the field study data were analysed and categorised based on the five clusters of the students. The outcome explained the aspects associated with the acoustical preferences of students in each cluster. Building-related indicators such as the location of the building were found as an aspect that could affect the student's acoustical preferences. This study provides insight into the profiles of students based on their acoustical and psychosocial preferences, which are important for their health and comfort at their study places.
Using mobile air cleaners in school classrooms for aerosol removal
Which, where and how
Journal article
(2024)
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Er Ding, Arghyanir Giri, Antoine Gaillard, Daniel Bonn, Philomena M. Bluyssen
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 rate (CADR), and 2) a perception test with a panel of subjects, together with physical measurements, of noise and air movement. The findings show that to achieve the desired CADR (appr. 1000 m3/h for 30 students per classroom), the key factors are the induced airflow pattern and the location of the MACs. MACs with an upward air supply toward the occupied zone showed much higher CADR (max. 775–1332 m3/h) than those with a horizontal air supply (max. 219–333 m3/h). Moreover, using multiple devices simultaneously was crucial when the room size was increased, and combining mechanical ventilation could improve aerosol removal. Achieving a sufficient CADR would always lead to a noise level above the limit of 35 dB(A), yet sometimes the rating of the panel was more than 50% acceptable. The air velocities mostly fulfilled the requirement (<0.2 m/s), which aligned with the positive panel assessment. Hence, the evaluation by a panel of subjects can help to optimize the use of MACs in a classroom.
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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 rate (CADR), and 2) a perception test with a panel of subjects, together with physical measurements, of noise and air movement. The findings show that to achieve the desired CADR (appr. 1000 m3/h for 30 students per classroom), the key factors are the induced airflow pattern and the location of the MACs. MACs with an upward air supply toward the occupied zone showed much higher CADR (max. 775–1332 m3/h) than those with a horizontal air supply (max. 219–333 m3/h). Moreover, using multiple devices simultaneously was crucial when the room size was increased, and combining mechanical ventilation could improve aerosol removal. Achieving a sufficient CADR would always lead to a noise level above the limit of 35 dB(A), yet sometimes the rating of the panel was more than 50% acceptable. The air velocities mostly fulfilled the requirement (<0.2 m/s), which aligned with the positive panel assessment. Hence, the evaluation by a panel of subjects can help to optimize the use of MACs in a classroom.
To investigate the feasibility of using mobile air cleaners (MACs) in school classrooms for reducing respiratory aerosols, a test on aerosol removal of seven different types of MACs was conducted in a university classroom, for the optimal condition determined by a prior experimental study. Most of the MACs achieved a good level of clean air delivery rate (CADR) (900-1000 m3/h), and the CADR increased with the number of devices used. Based on the results, three MACs were further selected for conducting an ongoing field study in 45 classrooms at five Dutch primary schools. Each classroom was assigned one type of MAC with two devices, and was monitored for a period of six weeks with three weeks the devices turned on and three weeks off. The assessments of feasibility are based on measurements of indoor air quality, information on absenteeism of the pupils, and interviews with the occupants. The results are yet to be collected to draw further conclusions. However, problems were already encountered during the installation process of the devices which hindered the realization of the pre-determined strategies.
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To investigate the feasibility of using mobile air cleaners (MACs) in school classrooms for reducing respiratory aerosols, a test on aerosol removal of seven different types of MACs was conducted in a university classroom, for the optimal condition determined by a prior experimental study. Most of the MACs achieved a good level of clean air delivery rate (CADR) (900-1000 m3/h), and the CADR increased with the number of devices used. Based on the results, three MACs were further selected for conducting an ongoing field study in 45 classrooms at five Dutch primary schools. Each classroom was assigned one type of MAC with two devices, and was monitored for a period of six weeks with three weeks the devices turned on and three weeks off. The assessments of feasibility are based on measurements of indoor air quality, information on absenteeism of the pupils, and interviews with the occupants. The results are yet to be collected to draw further conclusions. However, problems were already encountered during the installation process of the devices which hindered the realization of the pre-determined strategies.