Perceived Indoor Air Quality Research Articles

The Impact of Green Building Design on Indoor Air Quality and Occupant Experience

This study examines the impact of green building design on indoor air quality (IAQ) and occupant experience, using Heritage Place in Ikoyi, Lagos, as a case study. Green buildings are known for incorporating sustainable practices such as the use of eco-friendly materials, advanced ventilation systems, and biophilic design elements, all aimed at enhancing environmental sustainability and occupant well-being. A descriptive survey methodology was employed, with data gathered through a questionnaire administered to 50 occupants of the building to assess their perceptions of IAQ, health, comfort, and overall satisfaction. The findings indicate that the majority of respondents reported high levels of satisfaction with IAQ, attributing improvements in their health, productivity, and comfort to the building’s green design features. Specifically, low-emission materials and enhanced ventilation systems were highly praised for reducing pollutants and maintaining a healthy indoor environment. However, a few respondents expressed concerns about inconsistent thermal comfort in certain areas. These results underscore the importance of sustainable design in creating healthier, more productive indoor environments. Recommendations for future green building projects include fine-tuning HVAC systems to improve thermal comfort and enhancing occupant education on the benefits of sustainable features.

Assessment of Perceived Indoor Air Quality in the Classrooms of Slovenian Primary Schools and Its Association with Indoor Air Quality Factors, for the Design of Public Health Interventions

From a public health perspective, it is necessary to improve indoor air quality (IAQ) in schools. This study aims to assess the state of perceived IAQ in Slovenian school classrooms and its association with the selected IAQ factors to improve the understanding of perceived IAQ for designing public health interventions aimed to improve IAQ in schools. A national cross-sectional study was performed in all 454 Slovenian primary schools in the school year 2019/2020. The questionnaires were filled out by the 3rd-grade teachers with the support of the caretakers. Teachers rated the IAQ in the classroom as the worst in winter. We found that the teachers’ perceived IAQ in the classroom is statistically significantly associated with the micro location of the school and some of the IAQ factors. Poor IAQ is associated with reduced manual airing of classrooms due to the thermal comfort of the occupants. Interventions should be aimed at improving occupants’ adaptive behaviors to increase the frequency of natural ventilation in classrooms.

Factors influencing window opening behavior and mechanical ventilation usage during summertime: A case study in UK dwellings

The study presents findings of a data collection campaign conducted in 61 residential buildings in England during the summer of 2022, aiming to investigate the factors influencing 1) window usage, and 2) activation and deactivation of mechanical ventilation systems, and 3) the correlation between the residential soundscape, landscape, individual noise sensitivity, and the significance attributed to the external acoustic environment in determining window usage. The survey, covering 55 dwellings reliant on windows for ventilation, highlights that window opening is predominantly driven by perceived indoor air quality (PIAQ) and thermal comfort concerns. Conversely, the acoustic factor ranks first in prompting window closure, alongside considerations related to perceived cold, safety concerns, excessive drafts, and insect intrusion. Within the 6 dwellings utilizing manually controlled mechanical ventilation, ventilation needs emerges as the predominant factor triggering system activation, followed by considerations related to thermal comfort and PIAQ. Reasons for system deactivation primarily involve a preference for window opening, excessive drafts, and, secondarily, excessive noise or thermal discomfort, with participant-voiced concerns about operational costs. The significance attributed to the external acoustic environment in determining window usage is mainly independent of perceived sound sources, measured loudness, or soundscape content. However, higher acoustic comfort scores correlate with a greater willingness to open windows for an acoustic contact. Interestingly, noise sensitivity modulates the importance attached to the external acoustic context when interacting with the window (odds ratio: 1.04). The study underscores the need of incorporating noise sensitivity as a relevant individual factor in models simulating window closing behaviour.

Exploring public perceptions of indoor air quality under different quasi-experimental conditions: a UK case study

ABSTRACT The fast-growing sensing technology means there is an extensive range of low-cost indoor air quality (IAQ) devices or sensor modules readily available on the commercial market. However, less attention has been paid to exploring people’s perceptions and responses to indoor air pollution. Such knowledge is deemed important for improving the design of future IAQ sensors, enhancing public awareness and providing guidance on ways to improve indoor environmental conditions. This study aimed to explore people’s perceptions and responses to IAQ under different quasi-experimental environmental conditions and levels of information. The study is reported from the perspective of 16 staff and students at a UK university, held within a prototype smart and modular home built on campus. It compares questionnaire survey responses and focus group interview discussions with actual IAQ concentrations and other influential indoor parameters (indoor air temperature and relative humidity). Study outcomes revealed the importance of understanding contextual factors when developing feedback and communication strategies to best improve people’s awareness, acceptance, and behavioural responses to IAQ. Findings highlight the usefulness of focus group discussions in the design of future IAQ sensors.

Can Buildings Make Teachers Leave? The Complex Relationship Between Teachers and Their School Building: From an Interior Designer’s Perspective

ABSTRACT This study explores the link between perceived indoor air quality (IAQ) and teacher attachment in schools, focusing on 242 teachers across 38 buildings. It combines surveys assessing IAQ perceptions and health symptoms with in-depth interviews to understand teachers’ emotional ties to their workplaces. Findings indicate a significant relationship between IAQ concerns and negative place attachment, particularly among teachers experiencing health symptoms or dissatisfaction with ventilation quality, with teachers expressing detachment behaviors. The results underline the importance of addressing IAQ to enhance teacher retention and suggest a need for further research on interventions across various contexts.

The prevalence and association of measured and perceived indoor air quality, housing characteristics, and residents’ behavior and health

BackgroundIn social housing buildings, poor indoor air quality (IAQ) has been shown to be more prevalent, and residents living in social housing areas are often more vulnerable and susceptible to adverse health effects from IAQ.AimTo examine the state and the association of measured and perceived IAQ, how housing characteristics and residents' behavior are associated with IAQ, and the association with residents' health.MethodThe HOME-Health study is a cross-sectional study among residents living in social housing in Denmark (n = 432). Seasonal measurements examined the IAQ by a 14-day period measuring carbon dioxide (CO2), temperature (TP), relative humidity (RH), and air change rate. Residents' self-reported behavior, comfort, and health were obtained from a structured interview.ResultsThermal discomfort and draught were the most common challenges. During summer, the mean TP was higher, the mean RH was lower, and residents more frequently reported dry air in homes where it was not possible to create cross ventilation. There were a higher mean CO2 and RH when crowdedness increased, particularly during winter. In addition, the proportion of residents reporting dry air was higher when CO2-level was below 1,000 ppm. When the mean RH-level was above 50%, a higher proportion of residents reported experiencing damp air, and when the mean RH-level was below 40% residents more frequently reported dry air. Perception of bad air quality was higher when the mean CO2-level exceeded 1,000 ppm. Additionally, residents reported being most thermally comfortable when the TP was within the range of 20–20.99°C and least comfortable within a range of 22–22.99°C. The residents' perceived experience of impaired IAQ was associated with negative general health symptoms.ConclusionIt is key that homes have the capability to create cross ventilation in order to allow for proper ventilation and to avoid overheating. When evaluating IAQ it is important to not only consider the measured parameters but to also include the residents' behavior and perception of IAQ as these both are related to the actual IAQ and associated health effects.

Assessment of Indoor Particulate Matter and Teacher's Perceived Indoor Climate in Government Schools of Bilaspur District, Chhattisgarh, India: A Cross-Sectional Study.

Indoor air pollution (IAP) affects the long-term health, cognitive growth, and academic performance of children. Since children spend most of their time at school, quantifying IAP in classrooms is an important parameter for air pollution. To assess the average particulate matter (PM) levels inside and outside of classrooms along with their associated factors and teacher's perceived indoor climate. Cross-sectional survey in nine government-run schools. PM2.5 and PM10 were measured inside the classroom and outdoors simultaneously during summers, using an Atmos monitor for two consecutive days, along with several school and classroom characteristics. Perception about indoor air quality was captured from teachers (n = 15) using a validated questionnaire. Mean values of PM using mixed effect linear regression. Perceived indoor air quality is presented using percentages. Mean indoor PM2.5 and PM10 was 52.5 µg/m3 and 65 µg/m3. Indoor and outdoor PM levels were highly correlated, but the indoor-outdoor ratio of PM concentrations was more than 1. Teachers were mostly bothered by dust, dirt, and noise in the schools. Indoor air quality was higher than World Health Organization (WHO) standards but within the national standards. Need further research to find the exact cause for higher indoor PM levels compared to outdoor PM levels.

Perceived Air Quality, Thermal Comfort and Health: A Survey of Social Housing Residents in Kazakhstan

Kazakhstan is in Central Asia and is the ninth-largest country in the world. Some socially vulnerable segments of the Kazakh population residing in subsidised social housing have experienced a range of problems due to the low quality of housing construction and its planning. Poor indoor environmental conditions in social housing contribute to occupants’ comfort, health, and general well-being. This study assessed social housing residents’ health and quality of life, focusing on their perceived indoor air quality and thermal comfort satisfaction. A cross-sectional survey in Kazakhstan was conducted to test the effects of environmental factors on social housing residents’ health and satisfaction. Four hundred thirty-one responses were analysed, and the SF12v2 questionnaire was used to measure the health-related quality of life. Multiple regression analysis showed that air quality negatively predicted the respondents’ physical (PCS) and mental (MCS) health. In addition, age, smoking, and employment status had a significantly negative effect on PCS, while education level had a predictive positive effect. Thermal conditions negatively predicted only MCS, as well as alcohol consumption. Next, the air-conditioning control factor had a negative effect. In contrast, low air circulation, low humidity, high solar gain, temperature imbalance, duration of the residence and alcohol consumption had a significantly positive effect on overall satisfaction with the temperature. The odour sources from tobacco, furniture and external sources were predictors of respondents’ overall air quality satisfaction, along with the duration of the residence, alcohol consumption and smoking status.

How student perceptions of stuffy air and unpleasant odour are associated with students’ well-being: Cross-level interaction effects of school climate

It has been suggested that group-level factors affect how perceived indoor air quality (IAQ) is associated with well-being. Therefore, we analysed how student-perceived social climate at the school-level modified the student-level association between student-perceived unpleasant odour/stuffy air and well-being. The well-being indicators were seven self-reported anxiety symptoms (such as nervous, anxious, or on edge) and two somatic symptoms (headache and tiredness). We analysed a representative sample of Finnish school students (N = 678 schools, N = 71,392 students) by using multilevel modelling and testing cross-level interactions. At the student-level, both unpleasant odour and perceived stuffy air were significantly but weakly associated with increased anxiety and somatic symptoms. At the school-level, these IAQ indicators were significantly but weakly associated with increased anxiety and moderately with somatic symptoms. Furthermore, a good social climate at the school-level modified the student-level association between perceived stuffy air and anxiety symptoms. Those students who reported stuffy air were more anxious if they studied in a school with poor social climate than good social climate. Our results provide robust evidence that group-level factors may differently modify the relationships between different IAQ indicators and components of well-being.

Estimating perceived indoor air quality and environmental satisfaction using a camera

Although indoor environmental monitoring data are increasingly available, they often fail to accurately capture personal environmental perception, comfort, and satisfaction. This disconnection has led to a growing interest in using real-time feedback from building users to improve the control of heating, ventilation, and air-conditioning systems and reduce energy waste. However, traditional questionnaire-based surveys only provide a snapshot at the time of investigation and suffer from a variety of bias sources. To address this, this paper proposes a novel camera-based method for estimating perceived indoor air quality and environmental satisfaction by analysing facial expressions. We conducted indoor air pollution exposure experiments on 24 healthy adults in twin environmental chambers. Their changes in facial expressions were compared between different exposure conditions and the potential correlation between facial expressions and perceived air quality, environmental satisfaction, and self-reported sick building syndrome symptoms was explored. Preliminary results indicate that a common RGB camera can repeatably detect facial expressions from the same subject. Also, results from a subset of five subjects suggest moderate differences in concentration, calmness, contemplation, and tiredness expressions between the two air quality conditions.

A comparison study of environmental health related issues and policies between private and public U.S. schools using multi-level data

ObjectiveLittle is known about school environmental health (EH) problems in private schools. This study identified and compared the school EH related issues and policies between private and public schools in the U.S. MethodsSchool EH information was collected from school administrators on two levels – in New York State (NYS) and nationwide. In NYS, questionnaires were developed and distributed to administrators from both public and private schools via conferences (2015–2016). Nationwide survey data were obtained from the 2014 School Health Policies and Practices Study. We compared the perceived school environment as well as policies related to identification and training on EH issues between private and public schools both in NYS and nationwide. ResultsIn NYS, both private and public schools reported limited use of proactive approaches in identifying EH issues. Compared to public schools, more private school respondents reported poorer perceived indoor air quality (IAQ) (30% vs. 0%), along with less routine training and lower use of policies that help improve air quality in school. Nationwide, fewer private schools implemented indoor air quality management programs (18% vs. 58%) and were able to always meet ventilation standards (44% vs. 64%) than public schools. Staff members in private schools received less required training on a wide range of EH issues than staff members in public schools. ConclusionU.S. private schools reported worse perceived indoor air quality than public schools and a lack of awareness and protective policies. Future environmental research and implementation of policies are needed in private schools.

Potential benefits of short-term indoor exposure to sweet orange essential oil for relaxation during mental work breaks

With people's pursuit of a high-quality life, the use of essential oils to improve perceived indoor air quality has increased in recent years because of their pleasant odor. The smell-scape is increasingly being considered with respect to healthy building practices. To close the gap between the health benefits of essential oils and the incidental pollution problems, a cross-over study was conducted in an environment with lower concentrations of ozone and particulate matter based on a realistic method for their use. We compared the physiological parameters blood pressure, heart rate (HR), and heart rate variability (HRV), as well as various cognitive performance indicators, perceived indoor air quality, odor, and mood states between indoor environments with and without sweet orange essential oil. We alleviated the secondary pollution problem of essential oil by maintaining low-ozone spaces. During mental work breaks, the participants' HRV in the environment with sweet orange essential oil emission increased during four rest periods by 36.4%, 47.5%, 33.4%, and 25.0%, respectively, although there was no significant effect on cognitive performance between the control phase and the exposure phase. A significant increase in diastolic blood pressure following mental work indicated emotional stress and was confirmed by mood state evaluation. This stress was alleviated by exposure to sweet orange essential oil. The present study indicates that following a mental work period, the release of sweet orange essential oil has the potential benefits of promoting relaxation during a rest period, provided that the dose follows scientific dosage guidance, and that ozone and particulate matter concentrations are controlled.

Indoor Air Quality Perception in Built Cultural Heritage in Times of Climate Change

Low quality in a museum’s internal microclimate can induce both the deterioration of the exhibit collections, as well as affecting the health of visitors, employees and restorers. Starting from this premise, the present study aims to study the perception of visitors and employees of Darvas-La Roche Museum House (Romania) in relation to the air quality in the exhibition spaces. Their opinions were analyzed based on a questionnaire comprising 11 items aimed at understanding the influence of the indoor environment on the health of individuals, the degree of disturbance induced by the indoor air, if they experienced symptoms of illness after visiting the museum, etc. The obtained data were analyzed statistically in the SPSS 28 program, using tests such as coefficient, analysis of variance (ANOVA) and model summary, in order to obtain correlations between the sets of variables. The results obtained indicate that the majority of respondents perceived the indoor air quality as good, but there were also exceptions (approximately 20% of the respondents), which indicated different symptoms induced by the indoor air. Most of those (%) affected stated that they had pre-existing conditions, wear contact lenses or are smokers. In their case, the statistical-mathematical analyses indicated strong correlations between the ailments they suffer from and the appearance of certain discomforts (caused by too low or too high temperature, dust or dry air, etc.) and disease symptoms (nasal congestion, eye and skin irritations, coughs, migraines, frequent colds, etc.).

An effective alerting strategy to facilitate occupants’ perception of indoor air quality: By alarming concentration of indoor air pollution

Previous studies have proven that it is hard for occupants to perceive concentration of indoor air pollution (IAP) and resulting indoor air quality (IAQ) on their own. Therefore, a method is needed to encourage them to turn their attention to actual IAP, in this context, alerting is thus suggested. However, previous studies pose limitations in that they failed to analyze the effects of alerting concentration of IAP on occupants' IAQ perception. To fill the research gap, this study sought to explore a proper strategy to help occupants have a clearer perception of IAQ. A one-month observational experiment was conducted on nine subjects under three scenarios with different alerting strategies. In addition, the visual distance estimation method was used to quantitatively analyze similar tendencies between the subject's perceived IAQ and concentration of IAP for each scenario. The experimental results confirmed that when an alerting notification was not sent, the occupants could not clearly perceive IAQ as the visual distance was the highest at 0.332. On the other hand, when the alerting notification whether the concentration of IAP exceeded the standard or not was sent, the occupants could perceive IAQ relatively clearly as the visual distance was reduced to 0.291 and 0.236. In conclusion, not only installing a monitoring device but also establishing proper alerting strategies on the concentration of IAP is essential to facilitate occupants' IAQ perception and protect occupants' health.

Overlooked Impacts of Urban Environments on the Air Quality in Naturally Ventilated Schools Amid the COVID-19 Pandemic

The density, form, and dimensions of urban morphology are important for healthy living conditions in cities, especially if they are related to the climate and air pollution. Morphology and environmental conditions determine the relationship between open and built space, the width of street spaces, the aerodynamic characteristics of wind currents, albedo, and the retention of pollutants, as well as determining the radiative exchange with the atmosphere. Studies on the COVID-19 pandemic have focused on the assumption of a possible relationship between the spread of the SARS-CoV-2 virus and the presence and concentration of airborne particulate matter (PM10 and PM2.5). This paper focuses on the research of indoor air quality (IAQ) in two schools with naturally ventilated classrooms in Ljubljana, Slovenia. The presence of particulate matter (PM2.5 and PM10) and the concentration of CO2 were studied, along with other microclimatic conditions, e.g., ambient temperature, relative humidity, air pressure, and wind conditions. These were compared and assessed via analysis of variance (ANOVA) and Duncan’s post hoc test. The main concern was to see how effective different ventilation strategies are, as well as how the openings in the classroom impact the concentrations of CO2 relative to the concentrations of PM2.5 and PM10 particles as a side effect of these ventilation strategies. The inconsistent application of recommended COVID-19 ventilation strategies suggests that IAQ in naturally ventilated classrooms is highly determined by individual perceptions of indoor air quality. The results also suggest that the IAQ is significantly affected by the schools’ urban environment; however, this is not considered within the national COVID-19 ventilation recommendations. Future ventilation guidelines for pandemics should also include the urban environment as a risk factor for inadequate IAQ, instead of focusing solely on pathogen characteristics.

EVALUATION OF THE RELATIONSHIP BETWEEN SICK BUILDING SYNDROME PREVALENCE AND INDOOR AIR QUALITY IN SCHOOLS

In this study, it was aimed to evaluate the relationship between Sick Building Syndrome (SBS) prevalence and indoor air quality in primary and middle schools in rural and urban areas in the west of Turkey. This cross-sectional study was carried out between September and November 2018 in three randomly selected schools in rural and urban areas. The questionnaire designed to reveal perceived indoor air quality and SBS was completed by the parents of the students. On determined days, particulate matter (PM) and carbon dioxide (CO2) levels were measured in the classrooms. Multiple logistic regression model was developed to investigate the relationship between SBS and some variables. The study was conducted on 966 students. The prevalence of SBS was found to be 10.2%. The most common SBS symptoms were listed as fatigue, nasal congestion-discharge, cough, and headache, respectively. The measured PM2.5, PM10, and CO2 values were higher in the urban area than in the rural area. The risk of SBS was found to be higher in primary school students, in students who have poor perceived classroom air, lighting, and noise quality, and in students studying in classrooms with higher PM2.5, PM10, and CO2 values. One in ten students had SBS. There was a relationship between SBS and poor perceived indoor air quality and increased CO2 and PM values. Raising awareness about SBS and conducting studies aimed at improving related factors in schools are thought to be important.

User’s Perception of Indoor Air Quality (IAQ) in Tall Office Buildings as the Cause of Symptoms of Sick Building Syndrome

The user’s assessment or perception of indoor air quality (IAQ) refers to an individual’s subjective assessment or perception of the quality of the air they breathe inside a particular building or space. This assessment or perception is very individual and can vary from one individual to another. This study aims to determine the IAQ felt by users of the Rectorate Building, State University of Malang, and its effect on Sick Building Syndrome (SBS) symptoms. This research is included in the quantitative research with the study population being all employees at the building, which has 215 people. The data collection technique in this study used the MM040NA questionnaire and the data analysis technique used was binary logistic regression analysis with the help of the IBM SPSS Statistics with crosstabs test. The results of this study indicate that all independent variables have no significant relationship with SBS symptoms experienced by respondents and all independent variables have a very weak correlation. In addition, from 80 respondents, 27 people (33.75%) experienced SBS and 53 people (66.25%) did not experience SBS. This shows that there is a SBS phenomenon in the building. The significance value for all independent variables is greater than the significance level value (>0.05). Furthermore, based on the test criteria, it is concluded that the variable airflow, high temperature, temperature change, low temperature, stale air, dry air, odor, air electrostatics, cigarette smoke, sound level, lighting, and air pollution have approximate significance values greater than 0.05 (null hypothesis was failed to be rejected). It is concluded that those variables have no significant relationship to the dependent variable (the SBS symptoms) experienced by the respondents.

Impact of carpets on perceived indoor air quality

Indoor air quality (IAQ) plays an important role in human health and well-being as people spend most of their time indoors. Among building materials, carpets covering high surface areas and having dense fibres have the potential to impact perceived IAQ. To explore the impact of carpets on perceived IAQ, it was studied whether low-emitting wool carpets can ‘clean’ the air. To assess the sorption effect of emissions of hardboard (as a permanent source) on carpet, untrained subjects were asked to assess a combination of low-odour emitting carpet and hardboard in one sample container and only hardboard in another sample container of test chamber. The results showed a slight (although not statistically relevant) difference in favour of the combination, indicating a slight adsorption effect.

A Data-driven Causality Modeling Framework: An Empirical Study of Modeling the Effect of Indoor Air Quality Perception on Students' Cognitive Performance

In the information age, a paradigm revolution in applied data mining methods has emerged in response to the data explosion in management science research, but this artificial intelligence-based automated data-driven modeling process creates a new "big relationship" problem, where a large number of correlations obfuscate the identification of true causal relationships. In this paper, we use a causality modeling framework that combines correlation modeling and causality pruning processes. First, symbolic regression is used to model white-box correlations of human intelligence, and then spurious correlations that do not conform to causal graph theory are pruned so that ultimately causal relationships and explicit candidate models describing these relationships can be found automatically. In an empirical research problem, the framework is compared with a traditional hypothesis construction-validation process, and the results are consistent between the two. The proposed framework implements a data-driven "correlation + causation" automatic modeling capability, which will greatly improve modeling efficiency and reliability.

Critical analysis of monitoring indoor air quality in education centres

Indoor Air Quality perception in education centres has being a special concern based on their high occupancy and lack of ventilation. This study aims to present an overview of 20 relevant previous studies carried out in the last 5 years regarding monitoring and evaluating Indoor Air Quality in education centres. This analysis focuses on four specific aspects: general description of each study, ventilation typology, indicators measured and the number of locations measured. The results show that 60 % of the studies were located in an urban context, 75 % included primary schools and 75 % included naturally ventilated buildings. Indoor and outdoor was measured in 60 % of the studies. The most measured indicators were CO2 (60 %), PM2.5 (55 %), Temperature (50 %) and Relative Humidity (40 %) all indoor. In 60 % of studies were carried in more than five centres, mostly two rooms were measured and 35 % of studies placed one sensor per room. This can be a major limitation, as the monitored data may differ significantly from the actual situation. In conclusion, the greater correlations found relating to what indicators have been measured, were the ventilation typology and the location of the building, which influences what parameters and concentration can be expected.