Indoor Environmental Quality Factors Research Articles

The impact of IEQ in the university lecture theatres on students’ concentration levels in London

Purpose University students’ lecture theatre concentration levels are significantly related to indoor environmental quality (IEQ). The purpose of this study is to investigate the relationship between indoor environmental quality (IEQ) and the self-reported concentration levels of university students during the winter at University College London (UCL), UK. Design/methodology/approach A questionnaire survey and physical measurements were used to assess the IEQ factors affecting students’ concentration levels. Findings The lecture theatre design factor was the most significant factor influencing students’ concentration levels, and the facility environment was more important than the thermal environment, indoor air quality, and acoustic environment in influencing students’ concentration levels in this winter investigation at UCL, UK. Additionally, students prefer a colder thermal environment. The concentration level of students was positively correlated with the indoor air quality and negatively correlated with the acoustic environment. Practical implications Based on model application, this research could provide lecture theatre IEQ design. This research additionally provides an acceptable indoor thermal environment temperature range based on a large sample, which can be used to calibrate a student performance benchmark. Originality/value As this study evaluates the IEQ factors that influence the concentration levels of university students, interior designers and engineers should consider the rational layout of these factors. Therefore, this study may provide a reference for the interior environmental design of lecture theatres in educational buildings.

Impact of Indoor Air Quality and Multi-domain Factors on Human Productivity and Physiological Responses: A Comprehensive Review

Indoor environmental quality (IEQ) significantly impacts human health, well-being, and productivity. However, a comprehensive and in-depth review of the combined effects of IAQ and other multi-domain factors on human productivity is lacking. There has not been any prior review that encapsulates the impact of multi-domain factors on productivity and physiological responses of occupants. To address this gap, this review paper investigates and highlights the impact of IAQ and multi-domain factors (thermal, visual, and acoustic) on human productivity and occupant well-being in the built environment. The review explores various research methods, including evaluation of human productivity and creativity, data collection, and physiological signal analysis. We also examined the interactions between IAQ and multi-domain factors, as well as strategies for optimizing productivity through integrated building design and smart systems. The key findings from this review reveal that IAQ significantly impacts human productivity and occupant well-being, with interactions between IAQ and other IEQ factors further impacting these effects. Despite advances in the field, there are several limitations and gaps in the current research methods and study designs, including small sample sizes, limited and insufficient experimental design and control, reliance on laboratory or simulated environments, lack of follow-up and long-term data, and lack of robust performance metrics. The review proposes future research directions, including specific applications, and follow-up work to address these limitations and further advance the understanding of IAQ and multi-domain factors in the built environment. The implications of this review for policy and practice include the need for holistic and integrated approaches to IAQ and IEQ management, with a focus on creating healthy and productive indoor environments. This review emphasizes the importance of considering the complex interplay between IAQ and multi-domain factors, as well as the potentials of adopting smart control systems and sustainable design strategies to optimize productivity and occupant well-being in the built environment. By addressing these critical issues, we can enhance the overall quality of life for building occupants and contribute to a more sustainable future.

Driving forces behind the adoption of IEQ principles in building design: evidence from Nigerian quantity surveying firms

PurposeThe main objective of this study is to evaluate the driving forces behind the adoption of indoor environmental quality (IEQ) principles in building designs from the perspectives of Nigerian quantity surveying firms.Design/methodology/approachA quantitative approach was used which involved administering a well-structured questionnaire to a sample of 114 quantity surveyors. The collected data were analyzed using various statistical methods, including frequencies, percentages, mean item scores, Kruskal–Wallis test and exploratory factor analysis.FindingsThe top five ranked drivers were climate change mitigation, conservation of natural resources, reduction of waste and pollution, use of sustainable building materials and development of new materials and building systems. Based on the factor analysis, the study identified five clusters of drivers: (1) health and well-being drivers (2) economic drivers (3) environmental drivers (4) innovation and technology drivers and (5) regulatory drivers.Practical implicationsThe findings from this study suggest that to effectively integrate IEQ principles, quantity surveying firms should consider developing comprehensive guidelines and checklists that align with the identified drivers and clustered categories. These resources can serve as practical tools for project teams, facilitating a structured and holistic approach to the incorporation of IEQ factors throughout the project lifecycle.Originality/valueThe study’s identification of the top drivers and the subsequent clustering of these drivers into five distinct categories contributes to the existing body of knowledge on IEQ. This approach provides a structured framework for comprehensively understanding the factors influencing IEQ adoption, offering a valuable tool for researchers, policymakers and industry practitioners.

The Impact of Indoor Environmental Quality on Occupant Satisfaction in Commercial Buildings: A Comparison of Building Expert Opinions and Residents’ Experiences

This paper investigates the Indoor Environmental Quality (IEQ) factors influencing occupant satisfaction in commercial buildings in Iran, contrasting the views of building experts (architects and engineers) with those of building occupants. Employing the fuzzy analytical hierarchy process (FAHP), this study focuses on the four primary IEQ factors: thermal comfort, indoor air quality, visual comfort, and acoustic comfort. The study aims to bridge the gap between expert evaluations and occupant perceptions of IEQ factors in commercial buildings in Iran. By examining the disparities in prioritising IEQ factors between these two groups, the study sheds light on the complexities of IEQ assessment and highlights the importance of considering diverse perspectives in optimising indoor environments. Our methodology includes a survey conducted among 30 building experts (15 architects and 15 building engineers) and 102 occupants, employing FAHP to derive the relative importance weights of each IEQ factor. The results highlight significant disparities between architects, engineers, and occupants in prioritising these factors. Architects emphasise visual comfort (42%), while engineers and occupants view thermal comfort (53% and 41%) as the most crucial factor for occupant satisfaction. The study underscores the complexity of IEQ in commercial buildings and the diverse perspectives influencing its assessment. It contributes to the broader discourse on optimising IEQ, emphasising the need for a comprehensive approach that encompasses both technical expertise and occupant experience.

Impact of indoor environmental quality weighting schemes on office architectural design decisions

The importance of indoor environmental quality (IEQ) cannot be overstated, as it impacts the health and satisfaction of occupants. To evaluate overall indoor comfort, all four IEQ domains must be considered together. However, there is a lack of guidance on how to prioritize each domain and corresponding metrics, particularly during the early design stage. Therefore, this study investigates the effect of different weighting schemes on commercial building design elements to have high overall comfort. First, a parametric modeling approach for a shoe-box office building is developed to quantify IEQ domains using various design parameters. Subsequently, multiple weighting options are defined, resulting in an aggregated IEQ score. Next, high-performance designs are identified and compared based on each weighting scheme for two different climates. Results show that, as long as all four comfort domains are considered, the choice of weighting scheme does not significantly affect the selection of high-performance designs. Therefore, an equal weighting scheme is suggested for the early stage. This paper presents an original approach to support design decisions and the mutual weightings of IEQ factors.

Understanding Discrepancies between predicted and experienced (Dis)comfort for hospitalized Patients: Four Reasons explored

Hospitalized patients’ healing process is affected by their room’s indoor environmental comfort. Models are developed to predict (dis)comfort. However, discrepancies with experienced (dis)comfort occur. Four reasons have been identified for these discrepancies: (a) people adapt, (b) in their experiences, indoor environmental quality (IEQ) factors interact, and experienced (dis)comfort and adaptation differ (c) between people and (d) between settings. To better understand these reasons and their relationships, it was investigated how hospitalized patients’ experiences of their indoor environment relate to measurable values of IEQ parameters. A multiple mixed methods case study was conducted at Belgian hospital wards. Data collection included interviews, self-documentation by patients, questionnaires, sensor measurements of IEQ parameters, and simulations of indoor conditions. Data were analysed in separate and integrated ways. (a) Five adaptation strategies were identified. They seem to impact experienced comfort psychologically in different ways. (b) IEQ factors interact in experiences because their assessment is influenced by the overall comfort. Adaptation strategies enable achieving the highest conceived overall comfort. (c and d) What one considers as comfortable and the adaptation strategies one applies to achieve it differ between participants and between settings. This better understanding is an important step towards improving comfort predictions, and therefore reducing discrepancies.

Perception of Overall Quality of Life Among Occupants of Green and Non-Green Office Buildings in Malaysia

Indoor environmental quality (IEQ) has become an important component of building design because people tend to spend the majority of their time indoors. The main purpose of this study is to investigate the occupants’ overall perceived Quality of Life (QoL) experience in two green and two non-green office buildings. All four buildings are situated in Klang Valley, Malaysia, and they are open-plan office buildings. 162 questionnaires were administered to assess the relationship between individuals' perceived QoL and IEQ factors. The IEQ factors, classified into ambient conditions, designed environment, and behavioural environment, are found to impact QoL. Findings from the case studies reveal that the four buildings varied in the aspect of Behavioural Environment, where some of the IEQ factors in the green buildings were perceived as slightly uncomfortable. It was also found that several IEQ categories interact as a system in which improvement of occupants' QoL experiences cannot be accomplished solely through the instrumental components of IEQ, as the designed and behavioural environments have substantial impacts. Several missing factors linked to the Green Building Index (GBI) criteria were significantly correlated with the QoL experience of occupants.

Impact of Indoor Environmental Quality on Students’ Comfort in High School Buildings during the Summer Season in an Extreme Climate

Maintaining a satisfactory indoor environmental quality (IEQ) is an integral element of improving occupant health and well-being. In particular, IEQ is an essential factor in some facilities, such as school buildings, to improve student academic performance. This study employed an objective and subjective measurement approach to assess IEQ in a government high school (GHS) and a private high school (PHS) located in Oman, which is characterized by its extreme hot climate. A total of 212 high school students were surveyed during the summer season across 10 different classrooms to ascertain their perception of IEQ situations. The results suggested that most of the observed IEQ factors, including air temperature, relative humidity, and lighting levels across the classrooms in GHS and PHS, satisfied the ASHRAE standard, except the indoor air temperature, which was slightly above the maximum threshold of the European Standard (EN). The average indoor sound levels (>60 dB) exceeded critical limits of 35 dB for school buildings, which may pose the risk of high annoyance (HA) to 30% of students. Satisfactory predicted mean vote (PMV) and predicted percentage of dissatisfied (PPD) scores were obtained from both schools when they were evaluated against the ASHRAE standard compared with the EN standard. The maximum proportion of the students reported their classroom’s air temperature (33%), relative humidity (25%), and air movement (47%) levels as not acceptable, and thermal comfort (33%), visual comfort (22%), and air quality (41%) as bad (P < 0.001). Multiple regression analysis revealed a strong linear relationship between indoor air temperature (R2 = 0.89) and other IEQ parameters, while PPD (R2 = 0.45) and PMV (R2 = 0.17) showed a weak relationship with outdoor environmental factors. Outdoor air temperature and humidity levels accounted for greater changes in indoor air temperature levels in the PHS than in the GHS. Providing increased urban vegetation, green façade, and retrofitting and the utilization of passive cooling could help improve IEQ in Oman schools.

Interaction effects of indoor environmental quality factors on cognitive performance and perceived comfort of young adults in open plan offices in North American Mediterranean climate

While Indoor Environmental Quality (IEQ) factors in an environment co-exist, the interaction effects of these factors and their impacts on cognitive functioning and perceived comfort have not been comprehensively examined. In this study, the interaction effects between temperature, lighting Correlated Color Temperature (CCT), and noise levels on selective attention, sustained attention, creativity, acoustics, thermal, visual, and overall IEQ comfort of young adults in open-plan offices in North American Mediterranean climate were presented. In a mixed-design controlled experimental setting, 52 young adults were recruited, and their objective cognitive performance and subjective comfort were assessed through statistical analysis. The experimental set points included [20 °C, 25 °C], [2700 K, 6500 K], and [50 dB, 65 dB] for temperature, lighting color, and noise, respectively. Additionally, the work took into consideration the gender and Body Mass Index (BMI) of participants. The results show that temperature moderated the effect of noise level and lighting CCT on selective attention, while no effect of IEQ factors on sustained attention was found. Creativity was influenced by gender and its interaction with the noise level. Concerning perceived comfort, acoustic comfort varied significantly with temperature. Thermal comfort was influenced by the combined moderating effect of lighting CCT and BMI on temperature, while visual comfort was driven by the moderation effect of gender on lighting CCT. Overall comfort was affected by the noise level and temperature. Finally, cognitive performance indicators were correlated with perceived IEQ comfort votes. Based on the findings of this study, considerations of interactions between noise, lighting CCT, temperature, gender, and BMI can shape occupant-centric priorities for enhanced cognitive functioning and comfort.

Understanding occupancy patterns of university libraries in the post-pandemic era

Understanding occupancy patterns in buildings is crucial for energy system planning, energy model calibration, and occupant-centric operations for health and comfort. In this study, we detected and analyzed the occupancy patterns of university libraries, a building type that is largely overlooked in existing studies but can provide a unique opportunity to understand the human-building interactions given that occupants are free to choose their seats from hundreds of possible options in built environments. In libraries, occupants usually do not have fixed seats and pick seats within the built environment that they like, which provides a non-intrusive opportunity to carry out post-occupancy evaluations. We used the publicly available seat reservation data to analyze the occupancy patterns over one semester in four libraries, and proposed four metrics to capture important mobility parameters and behaviors at multiple spatial–temporal scales. We constructed two sets of databases consisting of around 70 million records of nearly 3,000 seats in 4 libraries, with seat-level resolution and sampling frequency of every 10 s. The informative data set depicts not only the overall spatial–temporal occupancy patterns, but also nuances associated with seats and visits. The daily flow of the main library exceeded two visits per seat. Half of the visitors stayed at the libraries for 3–6 h during a single occupancy. Semester schedules and campus accessibility together influence students’ decisions on when and to which library to go to, while even within the same zone, some seats were always more popular than their neighbors. We found that influential factors included privacy, distance to neighboring users, access to the outdoor environment (window), etc. besides the well-studied conventional Indoor Environment Quality factors whose importance might have been over-emphasized, and we summarize the balance of these attractive features as “semi-isolation”. This work provides fresh data for library occupancy modeling. Our findings can inform the design, operation and management of university libraries, emphasizing the importance of human-centric, sensory and biophilic designs.

Perceived fit of different office activities – The contribution of office type and indoor environment

Office spaces are often examined using comfort-based measures. Another view is the need-supply fit, which emphasizes the fit of the space for different activities. Here the influence of office types and satisfaction with indoor environmental quality (IEQ) factors on different activities' perceived fit was examined with a large global dataset consisting of 82 315 respondents. The office types included private offices, assigned workstations in shared offices, assigned workstations in open-plan offices, team tables, and flex offices. The IEQ factors were estimations of satisfaction with thermal conditions, noise, air quality, natural light, and office lighting. The perceived fit was the estimation of workplaces’ support for different office tasks classified into eight activity types. The largest proportion of respondents were dissatisfied with thermal conditions (30.7%) and noise (27.9%). However, only dissatisfaction with noise was strongly related to the perceived fit and explained alone 17% of perceived fit for concentrated work. All office types supported office activities well. Satisfaction with IEQ factors explained the perceived fit better than the office types. Satisfaction with IEQ factors alone explained 16−24% of the perceived fit depending on the activity type. Private offices were considered the best fit, especially for concentrated and confidential work as well as remote contacts. The study shows that the need-supply fit approach offers a slightly different perspective on office functioning than comfort-based approaches. Satisfaction with IEQ factors is crucial for functioning in an office. Special care should be paid to noise control especially with activities needing concentration, confidentiality, or special material.

Critical indoor environmental factors affecting productivity: perspectives from university staff and postgraduate students

ABSTRACT Indoor environmental quality (IEQ) of buildings plays an important role in affecting building occupants’ comfort, health and well-being. However, there is limited understanding of the critical IEQ factors that affect occupants’ work productivity in university office buildings. By surveying 204 people (72 university staff members and 132 postgraduate students) in a tertiary education institution in New Zealand, this research aimed to identify and rank the critical IEQ factors concerning their perceived productivity and how the perceived importance of these factors differed between staff and student cohorts. Statistical analysis identified a total of 16 IEQ factors as important in affecting work productivity, and 15 of them, except cleanliness of the office, could be grouped into four categories: (1) thermal comfort and lighting; (2) acoustics and privacy comfort; (3) spatial comfort and (4) aesthetics and views. Based on the identified critical IEQ factors, a framework was developed and can be used by building facility managers and designers in the tertiary education sector to optimize design solutions to improve building performance that is more conducive to their occupants. The findings from this research can inform the inclusion of design features that will enable staff and students using these buildings to achieve better productivity.

In the eye of the flourish wheel: an assessment of users’ health, well-being and productivity in university research rooms

ABSTRACT Indoor Environmental Quality (IEQ) is an immense concern for people’s wellness. The central argument in this research is that the IEQ in a university research room impacts users and their health, well-being and productivity. In addition, the present study relies on the Flourish Wheel to enhance the environment using the Biophilic Design approach, which in turn influences users’ satisfaction and work performance in five research rooms at Brunel University London. These rooms are situated in the same outdoor environment of a single university campus, but house multi-disciplinary occupants and vary in construction age, size, methods of ventilation and mode of thermostatic control. The current research paper firstly investigated the role of IEQ factors and sub-factors on occupants’ health, well-being, and productivity. Secondly, evaluated the possibility of improving the indoor workplace environment using Biophilic Design patterns. The most prominent finding is that the qualities of the five critical aspects of IEQ have significantly positive correlations with the occupants’ wellness. Another significant result is that the 14 Biophilic Design framework patterns can holistically offer different ways to improve the research rooms based on various environmental issues. The findings proposed in this study could be valuable both for design practitioners and academic researchers.

Effects of indoor environment factors on productivity of university workplaces: A structural equation model

How are the indoor environment factors affecting the work productivity of office users in university buildings? Statistical analyses were undertaken on data probing building usage and self-reported indoor environment quality (IEQ) perception from a survey of 157 postgraduate students and 89 staff members at a university in New Zealand. Results of the partial least squares structural equational modelling confirmed the positive correlation among the IEQ within an office, the wellbeing and comfort as well as three dimensions of work productivity. IEQ factors relating to aesthetics and views were found to have the strongest effect on wellbeing and comfort as well as productivity for postgraduate students, whereas factors related to spatial and cleanliness are the most important for staff members. For both cohorts, the wellbeing and comfort in the office have significant direct effects on contextual performance, which indirectly further affects office users’ ability in time management and task performance. The findings highlight the importance of the inclusion of design features that are productivity and wellbeing oriented across the building and the need for appropriate consultation with university office building users (e.g., students and staff) to achieve optimised design solutions.

Home Indoor Environmental Quality and Attention Deficit Hyperactivity Disorder

Indoor environmental quality (IEQ) has been found to influence children’s health and behaviour, particularly conditions, such as attention deficit hyperactivity disorder (ADHD). This research aimed to ascertain whether housing IEQ impacted the symptoms of ADHD and its related behaviours. This study involved 435 parents of children and adolescents (aged 5–17) with ADHD residing in Australia. We utilised an online survey tool comprising the home version of the ADHD Rating Scale for Children and Adolescents and the Housing Environmental Quality Assessment Tool. The findings revealed that all the housing IEQ factors were associated with both the diagnosis and the severity of the symptoms. The results indicated that, for over one in ten children with ADHD (13.3%), the diagnosis was impacted by a collective contribution of air quality, acoustic quality, lighting quality, and the thermal comfort within their home. The air quality and the thermal comfort predicted a 4% variance in the severity of inattention. Additionally, air and lighting qualities predicted a 9.7% variance in the severity of hyperactivity-impulsivity, and all the factors of air quality, acoustic quality, lighting quality, and thermal comfort predicted a 10.9% variance in the severity of combined ADHD. In conclusion, this research provided insights into the importance of housing features and suggests that improving the housing indoor environmental quality, mainly thermal comfort, air, and lighting quality, could positively correlate with alleviating ADHD symptoms and severity among children and adolescents. Therefore, ensuring an appropriate indoor environmental quality should be prioritised in housing design, modification, and building, especially for those with ADHD.

Influence of indoor environmental quality and dwelling satisfaction aspects on overall satisfaction: Findings from a Swedish national survey

The objective of this study is to contribute to the discussion on the impact of dwelling satisfaction aspects (size, standard, layout, appearance/aesthetics, well-being, cost and area/neighbourhood) and perceived indoor environmental quality (thermal comfort, air quality, satisfaction with daylight and acoustic comfort) on occupants’ overall satisfaction. This article uses data from the Swedish National Survey, BETSI (2007/08). The results are representative of adults living in multi-family and single-family buildings (1597 responses/955 buildings). Linear regression models are developed with overall satisfaction as the dependent variable and independent variables: seven satisfaction aspects, four indoor environmental quality factors and all combined (eleven). An all-model explained 54.7% of the results (best performed). All the retained variables (except satisfaction with daylight) are statistically significant predictors. Satisfaction with well-being (b = 0.286) and satisfaction with dwellings’ standard (b = 0.188) have the greatest effect on overall satisfaction. The model with the IEQ aspects explained only 35.5% of the results. Reliability statistics (Cronbach’s alpha) and confirmatory factor analysis have been implemented in the dataset. The responses can be categorized into two clusters. The two clusters were significantly different across living duration, dwelling type, age category and tenure status.

A review on indoor environmental quality in sports facilities: Indoor air quality and ventilation during a pandemic.

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.

Associations of Indoor Environmental Quality Parameters with Students' Perceptions in Undergraduate Dormitories: A Field Study in Beijing during a Transition Season.

A healthy and comfortable dormitory environment is crucial to the quality of students' daily lives. In this field study, the indoor environmental quality (IEQ) parameters of undergraduate dormitories in Beijing were measured, while questionnaire surveys were conducted to evaluate the corresponding subjective perceptions of students. Integrated environmental monitoring kits were used to collect temperature, relative humidity, CO2, PM2.5, PM10, TVOC, formaldehyde, and noise data in the investigated dormitories, during the transition season from winter to spring. Questionnaires and scales were distributed to obtain the students' subjective perceptions of and satisfaction with the IEQ, and their health and well-being status. The measured IEQ data showed that the thermal environment tended to be warm and dry during the heating period. The CO2 concentrations seriously exceeded standard levels due to insufficient indoor natural ventilation. Noise exposure could sometimes interfere with students' rest. The students' overall satisfaction with the dormitory environment was low, especially in terms of air quality and acoustic environment. The unsatisfactory IEQ factors have led to several health symptoms, poor sleep quality, and slightly lower well-being. Correlations were found between the IEQ parameters and the corresponding subjective perceptions and satisfaction levels. It was speculated that students' satisfaction and well-being could be effectively improved by appropriately adjusting the corresponding IEQ parameters.

Skin morbidity in Indigenous children in relation to housing conditions in remote communities in Northwestern Ontario, Canada.

Elevated rates of eczema and skin infections in Canadian First Nation (FN) communities are of concern to families, community leaders and healthcare professionals. To determine whether skin morbidity was associated with indoor environmental quality factors in Canadian FN children living in remote communities. We quantified indoor environmental quality (IEQ) in the homes of FN children aged < 4 years of age living in four remote communities in the Sioux Lookout region of Northwestern Ontario, Canada. We conducted a quantitative housing inspection, including measuring surface area of mould (SAM), and monitored air quality for 5 days in each home, including carbon dioxide and relative humidity and quantified endotoxin in settled floor dust. We reviewed the medical charts of participating children for skin conditions and administered a health questionnaire. Relationships between IEQ and skin infections or eczema were evaluated using multivariable regression. In total, 98 children were included in the descriptive analyses, of whom 86 had complete data and were evaluated in multivariate analyses for dermatological outcomes (mean age 1.6 years). Of these 86 children, 55% had made ≥ 1 visits to the local health centre (HC) for skin and soft tissue infections and 25.5% for eczema. Unexpectedly, annualized eczema visits were inversely associated with SAM (RR = 0.14; 95% CI 0.01-0.93). There was a trend suggesting an inverse relationship between endotoxin and HC encounters for eczema and skin and soft tissue infections. Skin infections were common in this population of FN children. IEQ did not appear to be associated with skin infections or eczema. Mould exposure appeared to be inversely associated with HC encounters for eczema, possibly related to complex microorganism-host interactions occurring early in life.

Weighting of indoor environment quality parameters for occupant satisfaction and energy efficiency

Sustainable retrofit can increase a building's performance and extend its lifetime. Common sustainable retrofit guides usually ignore the building's indoor environmental quality (IEQ) and occupant satisfaction while only focus on the energy efficiency. During the retrofit, prioritizing improvements to IEQ parameters that are critical for increasing occupant satisfaction but do not considerably increase energy consumption is crucial given the budgetary constraints. This project aims to identify different building experts' perspectives on the impact of IEQ factors and underlying parameters that contribute to occupant satisfaction and energy efficiency in office buildings, and develop an index that ranks the IEQ parameters' overall cost-effectiveness in a sustainable retrofit. The study surveys the views of 30 carefully selected building experts (ten architects, ten building engineers, and ten building assessors) in Australia using multiple criteria decision-making method. Results show that the building engineers and assessors regard thermal comfort as the most critical factor influencing occupant satisfaction, 54.2% and 57.6%, respectively. Alternatively, the architects regard visual comfort as the most important (38.8%). All expert groups have a similar opinion on the relative importance of IEQ factors in office energy consumption. An IEQ Effectiveness index is developed to evaluate the cost-effectiveness of improving a specific IEQ parameter in achieving high occupant satisfaction while not demanding extra energy input. Visual and acoustic IEQ parameters turn out to be ideal IEQ parameters that can be prioritized in a retrofit. Results from this study can provide guidance for the decision-making process of the office building sustainable retrofit.