Impact Of Indoor Environmental Quality Research Articles

Comprehensive analysis of classroom microclimate in context to health-related national and international indoor air quality standards.

Indoor air quality (IAQ) and indoor air pollution are critical issues impacting urban environments, significantly affecting the quality of life. Nowadays, poor IAQ is linked to respiratory and cardiovascular diseases, allergic reactions, and cognitive impairments, particularly in settings like classrooms. Thus, this study investigates the impact of indoor environmental quality on student health in a university classroom over a year, using various sensors to measure 19 environmental parameters, including temperature, relative humidity, CO2, CO, volatile organic compounds (VOCs), particulate matter (PM), and other pollutants. Thus, the aim of the study is to analyze the implications of the indoor microclimate for the health of individuals working in the classroom, as well as its implications for educational outcomes. The data revealed frequent exceedances of international standards for formaldehyde (HCHO), VOC, PM2.5, NO, and NO2. HCHO and VOCs levels, often originating from building materials and classroom activities, were notably high. PM2.5 levels exceeded both annual and daily standards, while NO and NO2 levels, possibly influenced by inadequate ventilation, also surpassed recommended limits. Even though there were numerous exceedances of current international standards, the indoor microclimate quality index (IMQI) score indicated a generally good indoor environment, remaining mostly between 0 and 50 for this indicator. Additionally, analyses indicate a high probability that some indicators will exceed the current standards, and their values are expected to trend upwards in the future. The study highlighted the need for better ventilation and pollutant control in classrooms to ensure a healthy learning environment. Frequent exceedances of pollutant standards can suggest a significant impact on student health and academic performance. Thus, the present study underscored the importance of continuous monitoring and proactive measures to maintain optimal indoor air quality.

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

PurposeUniversity 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/approachA questionnaire survey and physical measurements were used to assess the IEQ factors affecting students’ concentration levels.FindingsThe 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 implicationsBased 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/valueAs 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.

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.

Study of the Impact of Indoor Environmental Quality in Romanian Schools through an Extensive Experimental Campaign

Decentralized ventilation systems in schools are becoming more important due to the focus on indoor air quality and energy economy. The research aims to explore how these technologies affect classroom air quality, thermal comfort, and noise. The study examined four decentralized ventilation systems in a real-world school using field measurements and data analysis. This included measuring the CO2, temperature, noise, and thermal comfort using the Predicted Mean Vote (PMV) index. All systems greatly improved the air quality, keeping CO2 levels within suggested limits. They failed to control indoor humidity, often lowering it to below optimal levels. Noise surpassed the 35 dB(A) criteria at maximum operation but was acceptable at lower airflows. Noise and air drafts did not bother residents. The study found that decentralized ventilation systems improve air quality and are easy to adapt to, although they need humidity control and noise management at higher operational levels.

Investigating the impact of indoor environmental quality and internal design on students' satisfaction in Tehran and North Cyprus dormitories

PurposeThis study was conducted to investigate the impact of indoor environmental quality (IEQ) and internal design on the performance of students in university dormitories in Tehran and North Cyprus.Design/methodology/approachUsing a survey questionnaire, 298 students living in student dormitories in Tehran and North Cyprus were surveyed for data collection.FindingsResearch has shown that the academic performance and well-being of students are heavily impacted by factors related to IEQ and internal design. The study conducted in Tehran and North Cyprus has identified the most effective components of IEQ and internal design for student dormitories. The study suggests that proper ventilation, furniture design, temperature control and lighting design are key factors that significantly affect IEQ and internal design. Control and lighting design are key factors that significantly affect IEQ and internal design.Originality/valueOriginality: The study utilizes a comparative study designed to analyze the differences and similarities between the two locations.

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.

The Impact of Indoor Environmental Quality (IEQ) in Design Studios on the Comfort and Academic Performance of Architecture Students

This study addresses the limited research on examining comfort levels among architecture students. Specifically, it seeks to evaluate indoor environmental quality (IEQ) within design studios to investigate the occurrence of health symptoms and ascertain the influence of these factors on academic performance. This study was conducted at a university in Jordan during the autumn semester. The research database encompassed objective measurements utilizing instruments, subjective aspects using questionnaires, and academic performance assessments. This study’s results indicated a significant need for more satisfaction with the overall comfort levels encountered in design studios. The element of noise levels was considered the least satisfactory by the students, followed by the level of humidity, temperature conditions, lighting quality, and air quality. The findings revealed that the symptoms most frequently reported weekly throughout the autumn semester in design studios were decreased focus, dry skin, nasal congestion, and headaches. A significant positive link was seen between the degree of concentration and academic achievement. Moreover, a significant majority of students (77.4%) expressed their belief that enhancing IEQ will improve their academic performance.

Impact of indoor environmental quality (IEQ) factors on occupants' environmental perception and satisfaction in hospital wards

The hospital ward's environment directly impacts the health and well-being of its occupants, especially patients. This study investigated the impacts of environmental factors (thermal, acoustic, luminous, and IAQ) and self-described health conditions on subjective environmental perception and satisfaction in hospital wards. A winter field survey of 156 occupants (patients and visitors) was conducted in a large general hospital in Changsha, China, using a combination of environment measurements, questionnaires, and interviews. The results showed comprehensive effects of environmental factors on occupants' perceptions. Lower air temperature improved participants' assessment of the acoustic environment; lower noise environment led to a positive assessment of IAQ perception; lower CO2 concentration improved the assessment of the thermal environment in a hotter environment. Acoustic perception (13.4 %), IAQ perception (10.5 %), and luminous perception (8.2 %) were significantly affected by health conditions. Moreover, the poorer the health condition, the lower the environmental satisfaction rating, and the acceptable environmental thresholds differed for individuals with various health conditions. The "very weak" group scored 1.6 and 1.5 points lower than the "very fit" for each environmental factor and overall satisfaction, respectively. For IEQ control in healthcare facilities, it is necessary to fully consider patients' health conditions during hospitalization and create a better recuperation environment for vulnerable groups.

Analyzing the impact of indoor environmental quality on physiological responses and work performance: Implications for IEQ control strategies

This study aims to analyze the effects of indoor environmental quality (IEQ) factors with simultaneous changes in illuminance and noise levels on building occupants' physiological response and work performance. To this end, four scenarios with changes in illuminance and noise levels were set up, and brain wave indices and work performance measured through a Stroop test were conducted during the scenarios. First, the findings revealed that noise and the interaction between illuminance and noise affect the building occupants' physiological response. Second, the illuminance was 150 lux, and the noise level was 40 dB, there was a correlation between the relative theta (0.685; p < .05) at the F3 location on the scalp and the average reaction time. Lastly, a comparison was made between psychologically preferred IEQ, IEQ when the physiological response is excellent, and IEQ when work performance is excellent. IEQ when the physiological response is excellent showed a high correlation with psychologically preferred IEQ, and it had a higher correlation with IEQ when work performance is excellent than psychologically preferred IEQ. Hence, an IEQ control strategy based on the physiological responses is necessary to improve work performance. It is expected to enhance building occupants’ work performance, health, and comfort.

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.

Examining the indirect effects of indoor environmental quality on task performance: The mediating roles of physiological response and emotion

Most studies have been conducted on the impact of indoor environmental quality (IEQ) on occupants' task performance. However, most studies are based on the assumption that IEQ directly affects task performance. Different hypotheses have been proposed that contradict this conventional belief. The objective of this study is to examine the indirect effects of IEQ on task performance. To identify unknown mediating variables between IEQ and task performance, two research hypotheses were set up: (i) Emotion is the result of a physiological response change in the body and would be influenced by the IEQ in the built environment; and (ii) Task performance would be influenced by IEQ-evoked emotion of occupants. The partial least squares structural equation modeling (PLS-SEM) was employed to verify two interrelated research hypotheses and conduct mediating effect analysis using SmartPLS 3.3.1. The results of this study demonstrated the following: (i) IEQ has no direct effect on task performance but has an indirect effect mediated by dominance resulting from skin conductance; (ii) hot and humid thermal environment and unpleasant indoor air quality increase human skin conductance, which in turn leads to passive emotions. The passive emotions that are not under direct human control result in the degradation of task performance. Using the findings of this study, future smart offices need to collect human bio-signals and emotions and manage IEQ based on these data unlike past smart offices that considered only environmental factors.

Transformative Service Research and impact of indoor environmental quality on workers’ productivity: Potentialities of neuroscience in its assessment

Previous research demonstrated that there is a link between workers’ productivity and their overall comfort in the workspaces. Nowadays, the energy crisis is highlighting the need for energy saving measures also in workplaces to reduce expenses, thus posing threats to the overall comfort of workers: how to deal with this trade-off? In such a frame, this paper is a traditional literature review of the research, conducted so far, useful to understand the optimal point of energy needed to secure human wellbeing in workspaces (and thus, acceptable productivity). Moving from an overview of the most common adopted methodologies and related findings, this work focuses on applications and opportunities associated with merging methods from neuroscience. Neuroeconomics, in fact, uses some indexes (cognitive interests, mental fatigue) and techniques (EEG, heart rate) that allow to understand whether a person is focused on his/her work or not: this can represent a double-check of the optimal level of environmental comfort in offices. Environmental comfort studies concerning the adoption of physiological monitoring are compared here to business management studies lying on physiological indexes to assess employees’ interest and cognitive effort, which influence their productivity. This comparison showed up new perspectives in the investigation of occupants’ productivity and environmental comfort, which can be pursued in the coming years to understand how to achieve the optimum between energy consumption and workers’ productivity.

The impact of indoor environmental quality (IEQ) on patients' health and comfort in Nigeria

PurposeThe most challenging aspect of hospital design is the creation of an environment that heals rather than the one acting as a barrier to healing. Much has not been done in the aspect of ascertaining the level of impact “indoor environmental quality (IEQ)” has on building occupants in healthcare facilities. Therefore, this study aims to investigate the impact of IEQ on patients' health and well-being.Design/methodology/approachThe study investigates the hypothesis that four IEQ parameters (thermal quality, acoustic quality, lighting quality and indoor air quality [IAQ]) influence patients' overall satisfaction with the performance of hospital wards. Questionnaire responses were sought from the patients as the main occupants of hospital ward buildings. A proposed weighted structural model for IEQ establishing the relationship between IEQ parameters, patients' overall satisfaction and patients' health outcome was analyzed using structural equation modeling (SEM).FindingsThe most influential IEQ parameters on patients' overall satisfaction with IEQ in hospital wards are thermal quality, IAQ and lighting quality. The findings from this study revealed that the parameters of influence on patients' overall satisfaction and health outcomes vary with hospital ward orientation and design configuration.Originality/valueThis study has explored the need for the integration of all factors of IEQ at the building design stage towards providing a hospital environmental setting that reflects occupants' requirements and expectations and also promotes patient healing processes. This should be the focus of architects and healthcare managers and providers.

Impact of Indoor Environmental Quality on Hotel Guests’ Behaviors

ABSTRACT This study explores the impact of indoor environmental quality (IEQ) (i.e., indoor air quality, thermal comfort, acoustic quality, and interior space and furnishings) on overall service quality (OSQ), customer satisfaction, and customer loyalty. Hotel guests were selected to examine the proposed IEQ model developed grounded on the Mehrabian-Russell model and Bitner’s conceptual model. To analyze the data, the PLS-SEM was utilized. Results indicate the following significant relationships: between interior space and furnishings and OSQ, between interior space and furnishings and customer satisfaction. Results also show that two significant factors influencing customer satisfaction are thermal comfort and IAQ. In turn, they influence customer loyalty. Implications for researchers and managers are discussed.

Triggering occupant behaviour for energy sustainability: Exploring subjective and comfort-related drivers in Brazilian offices

Indoor environmental quality, socio-psychological aspects, as well as contextual and personal factors, can be considered as multi-domain drivers for occupant behaviour (OB). Therefore, this study relies on a survey that bridges the gap between building physics and social psychology to implement an interdisciplinary framework into OB research. A case study was conducted in Florianópolis, southern Brazil. Results show that the impact of Indoor Environmental Quality (IEQ) parameters on respondents’ satisfaction is correlated with their influence on perceived productivity. Besides this stand-alone effect, IEQ-beliefs related to indoor temperature and air quality are correlated. The main sources of environmental discomfort and reasons for OB were analysed and provided a basis for further evaluations. Then, the twofold relation between multi-domain discomfort and OB were represented in a flowchart. Our conclusions support that OB must be treated as multi-physics and multi-domain-comfort issues, as adaptive behaviours to restore occupants’ comfort may result in additional sources of discomfort. Finally, all the surveyed aspects – IEQ-beliefs, subjective, contextual, and personal factors – were used to perform decision-tree-based analyses to find the main predictors for behaviours. The first takeaway is that control over building systems is the principal driver for adjustments. Additionally, subjective aspects like IEQ-beliefs, frequency of negotiation to control building systems, attitudes, ease and intention towards sharing their control were also important predictors. It evidences that increased data-driven knowledge about those relations is essential in this field, and future monitoring and modelling approaches may be enhanced by incorporating them instead of focusing siloed on environmental parameters.

Impact of indoor environmental quality on job satisfaction and self-reported productivity of university employees in a tropical African climate

Indoor environmental quality (IEQ) studies in educational buildings have largely focused on students with limited attention on office workers in post-secondary institutions like universities, especially in developing and underdeveloped countries. University office workers, especially academics and professionals, have varied office use patterns that may influence their IEQ satisfaction and productivity. This research investigated differences in IEQ satisfaction factors (ventilation and thermal comfort, acoustics and privacy, and lighting), job satisfaction and self-reported productivity between academics and professionals in private, shared and open-plan offices. The data was collected using an adapted IEQ questionnaire survey that was administered online to employees of a university located in the tropical middle belt of Ghana. The results showed no statistically significant differences in IEQ satisfaction factors; however, professionals were generally more satisfied compared to academics. The impact of IEQ on productivity was positive for professionals and negative for academics except those in private offices; however, differences in job satisfaction between professionals and academics were insignificant. Correlation analysis suggested that improving IEQ of offices is likely to have positive impact on job satisfaction and productivity of both professionals and academics. Findings of this research would interest designers and managers of educational buildings in tropical climates seeking to meet the unique IEQ requirements of university office workers.

The Impact of Indoor Environmental Quality of Green Buildings on Occupants' Health and Satisfaction: A systematic review

Introduction: The main benefits of green buildings for energy and water conservation have been investigated and well recognized in previous studies. However, indoor environmental quality (IEQ) and human health benefits of green buildings have not been examined comprehensively. This study aimed to conduct a systematic review over the current status of green and non- green buildings on their occupants’ health and satisfaction. Method: A systematic search was conducted throughout the following databases: Science Direct, Google Scholar, and Springer. We reviewed 690 articles that examined the relationship between buildings and health. In total, after excluding the irrelevant titles and non-­English articles, 40 papers were included in the final analysis. Articles that evaluated IEQ factors and occupants’ health through surveys from 2005 to 2018 years were selected for investigation. Results: The most important result of this study was identification of important factors in IEQ, including building design, aesthetics, and ergonomics, which have been less evaluated in previous research. Contrary to our assumption, the results of several studies indicated a further decline in IEQ parameters in buildings with Leadership in Energy and Environmental Design (LEED, USA) and Building Research Establishment Environmental Assessment Method (BREEAM, Europe) certification. However, performance improvements were reported in green buildings located in Asia (especially Singapore and Taiwan). Conclusion: According to this systematic review, we cannot claim that occupants of the green buildings enjoy higher IEQ, satisfaction, or health, compared with the occupants of non-green buildings.

Individually controlled noise reducing devices to improve IEQ in classrooms of primary schools

Individually controlled noise reducing devices to improve IEQ in classrooms of primary schools

Culture, conformity, and carbon? A multi-country analysis of heating and cooling practices in office buildings

This study investigates human-building interaction in office spaces across multiple countries including Brazil, Italy, Poland, Switzerland, the United States, and Taiwan. We analyze social-psychological, contextual, and demographic factors to explain cross-country differences in adaptive thermal actions (i.e. cooling and heating behaviors) and conformity to the norms of sharing indoor environmental control features, an indicator of energy consumption. Specifically, personal adjustments such as putting on extra clothes are generally preferred over technological solutions such as adjusting thermostats in reaction to thermal discomfort. Social-psychological factors including attitudes, perceived behavioral control, injunctive norms, and perceived impact of indoor environmental quality on work productivity influence occupants’ intention to conform to the norms of sharing environmental control features. Lastly, accessibility to environmental control features, office type, gender, and age are also important factors. These findings demonstrate the roles of social-psychological and certain contextual factors in occupants’ interactions with building design as well as their behavior of sharing environmental control features, both of which significantly influence building energy consumption, and thus, broader decarbonization.

Development and field testing of a multi-dimensional tool for benchmarking knowledge worker productivity

ABSTRACTThe impact of indoor environmental quality on human health and well-being has been widely documented, as has its impact on worker productivity in settings such as education, healthcare, and manufacturing. In the knowledge worker context, however, there is limited consensus on agreed metrics for productivity measurement, leading to a paucity of research regarding the impact of specific real-workplace interventions on worker performance. This paper presents an organizational benchmarking and evaluation tool to permit such tracking within an organization. Based on the results of a systematic literature review, five dimensions are used to evaluate productivity in this context: absenteeism, presenteeism, engagement, self-assessed (individual) productivity, and objective (office-wide) productivity. This data is collected from organizational reports, individual employee questionnaires, and field data. The resultant tool was refined through a series of public- and private-sector field tests and the evaluation of results was undertaken through post-analysis interviews with organizational partners who provided feedback on the clarity of data as-presented, alignment with known issues, and consistency with other studies. The evaluated tool provides a holistic means of assessing knowledge worker productivity and will support future research to evaluate and quantify the impact of specific interventions in workplace policy and environmental modifications.