Search Results (78)

This study assessed the baseline indoor environmental quality (IEQ) of secondary school classrooms in Tanzania by measuring temperature, relative humidity, noise, lighting, and indoor air quality. Objective measurements were conducted using calibrated sensors in 14 classrooms across five schools, with data collected during occupied school hours and additional noise measurements during unoccupied periods. All classrooms are naturally ventilated through operable windows and doors. The findings reveal a pattern of cumulative IEQ deficiencies: classroom temperatures frequently exceeded the recommended 20–24 °C range, reaching means as high as 30.4 °C, while relative humidity varied widely, with levels occasionally surpassing 65%. Noise levels consistently exceeded the World Health Organization (WHO)’s recommended 35 dBA threshold, with significant differences observed between occupied and unoccupied periods (p = 0.02). Light distribution was uneven, with significantly higher lux levels near windows than at classroom centers (p < 0.001), and artificial lighting was generally insufficient due to infrastructure limitations. Although CO₂ concentrations remained below the 1000 ppm threshold, indicating adequate ventilation, particulate matter levels were often elevated, with PM2.5 reaching up to 58.80 µg/m³ and PM10 up to 96.90 µg/m³, exceeding health-based guidelines. Together, these findings suggest that students are exposed to multiple environmental stressors that may impair health, comfort, and academic performance. This study provides a critical baseline for future research and context-specific interventions aimed at improving learning environments in Tanzanian schools and similar settings in East Africa. Full article

As the demand for energy-efficient homes continues to rise, the importance of advanced mechanical ventilation systems in maintaining indoor air quality (IAQ) has become increasingly evident. However, challenges related to energy balance, IAQ, and occupant thermal comfort persist. This review examines the performance of mechanical ventilation systems in regulating indoor climate, improving air quality, and minimising energy consumption. The findings indicate that demand-controlled ventilation (DCV) can enhance energy efficiency by up to 88% while maintaining CO₂ concentrations below 1000 ppm during 76% of the occupancy period. Heat recovery systems achieve efficiencies of nearly 90%, leading to a reduction in heating energy consumption by approximately 19%. Studies also show that employing mechanical rather than natural ventilation in schools lowers CO₂ levels by 20–30%. Nevertheless, occupant misuse or poorly designed systems can result in CO₂ concentrations exceeding 1600 ppm in residential environments. Hybrid ventilation systems have demonstrated improved thermal comfort, with predicted mean vote (PMV) values ranging from –0.41 to 0.37 when radiant heating is utilized. Despite ongoing technological advancements, issues such as system durability, user acceptance, and adaptability across climate zones remain. Smart, personalized ventilation strategies supported by modern control algorithms and continuous monitoring are essential for the development of resilient and health-promoting buildings. Future research should prioritize the integration of renewable energy sources and adaptive ventilation controls to further optimise system performance. Full article

The COVID-19 pandemic highlighted the importance of indoor air quality in buildings for the well-being of their occupants. In long-term occupancy buildings such as schools, where environmental conditions also impact academic performance, this importance was heightened. Despite the significant changes in ventilation practices resulting from the pandemic, recommendations have varied across different countries. This study aimed to provide a comparative analysis of the environmental conditions and air quality in classrooms in southern Spain and northern Italy (representative Mediterranean locations with different post-pandemic heating and natural ventilation approaches). Data measured on-site during periods with similar outdoor conditions were analysed to ascertain how ventilation strategies influence thermal comfort and indoor air quality. According to the results, during mild periods, high-intensity ventilation ensures excellent indoor air quality results based on CO₂ concentrations, without compromising thermal comfort. Nevertheless, ventilation rates should be controlled in more adverse climate conditions to avoid negative effects on thermal comfort. Full article

People spend most of their time indoors, where air quality is crucial to health. In this context, this study conducts a critical review of ventilation strategies in schools to ensure air quality, as well as to guarantee students’ thermal comfort. Based on a bibliographical review, strategies from previous studies are identified and evaluated in order to determine their advantages. After a detailed search, a total of 19 articles were selected, which provides a thorough analysis of the ventilation strategies in school buildings considering thermal comfort. The identified strategies were categorized into natural, mechanical, and hybrid types. The results reveal a prevalence of natural ventilation, which accounts for over 50% of strategies in all climates. Mechanical ventilation is less common and is applicable to around 30% of cases. Hybrid strategies, combining natural and mechanical ventilation, are the least used and only appear in oceanic climates, with a usage rate of 20%. Most studies highlight the lack of air conditioning in many schools, making adequate thermal stress management through ventilation crucial. The results analyzed clearly show a lack of studies with optimal results whose ventilation strategies can be replicated in other similar educational buildings, ensuring thermal comfort and air quality. Full article

Indoor air quality (IAQ) in schools significantly affects health and academic performance; however, effective interventions for poor air quality remain limited, particularly in settings with restricted natural ventilation. This study evaluated the effectiveness of ventilation-type air purifiers in improving classroom IAQ in a South Korean elementary school. PM₁₀, PM_2.5, and CO₂ concentrations were monitored over 18 days (14–31 May 2021) in two classrooms—one equipped with a ventilation-type air purifier and the other serving as a control. In the classroom with the air purifier, daily average concentrations of PM₁₀, PM_2.5, and CO₂ decreased by 23.7%, 22.8%, and 21.1%, respectively, from baseline levels. The air purifier effectively reduced pollutant infiltration during periods of severe outdoor air pollution and stabilized pollutant levels during active class hours. Its efficacy was particularly prominent under conditions of restricted natural ventilation, high indoor activity, and fluctuating outdoor pollution levels. IAQ varied significantly between weekdays and weekends; pollutant levels were higher on weekdays due to occupancy and classroom activities, whereas weekends exhibited reduced concentrations. These findings suggest that ventilation-type air purifiers provide a viable strategy for improving IAQ in schools with limited ventilation. Future research should examine their long-term performance across different seasons and architectural settings. Full article

Indoor air quality (IAQ) plays a vital role in supporting both the physical and mental well-being of individuals in enclosed spaces, and the role of mechanical ventilation systems has gained increasing attention due to building design’s focus on energy efficiency and thus airtight constructions. This study investigated the pre–post effects of installing a heat recovery mechanical ventilation system (MVHR) on indoor air quality in a high school classroom in Ferrara, Italy. The analysis focused on experimental measurements of temperature (T), relative humidity (RH), and carbon dioxide (CO₂) both inside and outside the same classroom, which had constant occupancy (17 students) for an entire school year, allowing a comparison between natural and mechanical ventilation. With a comprehensive approach, particulate matter (PM_2.5), volatile organic compounds (VOCs), and radon levels (Rn) were monitored as well, after the installation of the MVHR. By comparing natural and mechanical ventilation, the study highlights the strengths and limitations of the ventilation system implemented, together with an evaluation of the system’s energy consumption, including a 2 kW post-heating battery. In terms of results, the MVHR demonstrated clear benefits in managing CO₂ levels and improving sensory, olfactory, and psychophysical well-being, as well as the attention levels of students. In detail, under natural ventilation, peak concentrations exceeded 4500 ppm, while mechanical ventilation kept them below 1500 ppm. The average CO₂ concentration during occupancy dropped from 2500 ppm to around 1000 ppm, achieving a 62% reduction. However, beneficial effects were not observed for other parameters, such as PM_2.5, VOCs, or radon. The latter displayed annual average values around 21 Bq/m³ and peaks reaching 56 Bq/m³. Full article

Most human time is spent indoors, and due to the pandemic, monitoring indoor air quality (IAQ) has become more crucial. In this study, an IoT (Internet of Things) architecture is implemented to monitor IAQ parameters, including CO₂ and particulate matter (PM). An ESP32-C6-based device is developed to measure sensor data and send them, using the MQTT protocol, to a remote InfluxDBv2 database instance, where the data are stored and visualized. The Python 3.11 scripting programming language is used to automate Flux queries to the database, allowing a more in-depth data interpretation. The implemented system allows to analyze two measured scenarios during sleep: one with the door slightly open and one with the door closed. Results indicate that sleeping with the door slightly open causes CO₂ levels to ascend slowly and maintain lower concentrations compared to sleeping with the door closed, where CO₂ levels ascend faster and the maximum recommended values are exceeded. This demonstrates the benefits of ventilation in maintaining IAQ. The developed system can be used for sensing in different environments, such as schools or offices, so an IAQ assessment can be made. Based on the generated data, predictive models can be designed to support decisions on intelligent natural ventilation systems, achieving an optimized, efficient, and ubiquitous solution to moderate the IAQ. Full article

This study assesses indoor air quality (IAQ) in two schools in the Democratic Republic of Congo (DRC), contributing scientific data for a developing tropic such as the DRC marked by the absence of sufficient study on the indoor environmental quality (IEQ) in school buildings. Over ten weeks, we monitored IEQ parameters in two schools, considering their unique geographical and environmental settings. Using a calibrated IEQ multiprobe and particle counters, we measured the CO₂ levels, temperature, relative humidity, and particulate matter (PM). Our data analysis, which included ANOVA and correlation assessments, revealed a concerning trend. We found that the CO₂ and PM concentrations in the classroom were significantly high, often exceeding recommended safety thresholds. The current natural ventilation systems were found to be inadequate, particularly in managing CO₂ concentrations and PM levels influenced by proximity to industrial activities. Our study recommends that schools in similar settings adopt mechanical ventilation systems with high-efficiency particulate air (HEPA) filters to improve IAQ. We also recommend regular monitoring and dynamic air quality adjustment based on real-time data to ensure the effectiveness of implemented interventions. Furthermore, we propose that future studies focus on a broader range of environmental conditions and include many schools and educational buildings to enhance the generalisability of the findings. Long-term health outcomes and the cost-effectiveness of different ventilation strategies should also be explored to develop adapted, sustainable interventions for improving student well-being and performance in schools globally. Full article

Indoor air quality (IAQ) in schools significantly impacts occupant health and academic performance, especially in naturally ventilated (NV) classrooms, where CO₂ levels are often elevated. This systematic review synthesises findings from 125 studies, examining CO₂ as an indicator of ventilation rates (VRs) and its impact on IAQ, health, and academic performance in NV primary school classrooms. This analysis highlights seasonal and temporal variations in CO₂ concentrations, revealing a median CO₂ concentration of 1487 ppm across 2444 classrooms, with 81% exceeding the recommended 1000 ppm threshold. Influencing factors include VR, occupant density, generation rates, and occupant behaviours. Increased VRs consistently lowered CO₂ levels and enhanced IAQ. CO₂ concentrations correlated with particulate matter, volatile organic compounds, bioeffluents, microbial concentrations, and bacteria and fungi levels, but not with traffic-related pollutants like NO₂, which is associated with asthma prevalence. Elevated CO₂ levels consistently correlated with fatigue, headaches, respiratory symptoms, reduced academic performance and absenteeism, suggesting potential socio-economic benefits of increased VRs. However, effective IAQ management requires balancing ventilation with considerations of thermal comfort, noise, and outdoor pollutants. The findings highlight the need for standardised IAQ indices and CO₂ monitoring protocols, offering insights for future research, intervention design, and investment aimed at enhancing classroom environments. Full article

In this paper, we use a path model to study natural ventilation in classrooms and research the link between air change rate, occupancy, and both outdoor and indoor physical variables. In general, the path model is derived from the building physics and occupant behavioral considerations via structural equation modeling (SEM), and allows for the use of continuous observable and unobservable factors. The latter are often employed in behavioral and social sciences to represent personal and group attributes. The path model is validated with data gathered during two consecutive academic years from four classrooms of a Portuguese school. The results confirm indoor and outdoor air temperature as major drivers of classroom ventilation, with standardized total path coefficients of approximately 0.55. Solar energy, precipitation, and occupancy are also significant drivers of classroom ventilation, with standardized total path coefficients of 0.24, −0.18, and 0.17, respectively. These results contribute to our understanding of the relative importance of occupancy as well as to identifying the most relevant environmental determinants of natural classroom ventilation. In spite of the statistical significance of the path model as a whole and its detailed causal relationships (direct, indirect, and feedback), only 58% of classroom ventilation variance is explained by the selected input variables. Because naturally ventilated classrooms depend significantly on occupants’ interactions with the built environment, i.e., opening/closing windows and blinds, extending path modeling to include additional personal and context-related drivers of occupants’ behavior would allow for further insights into the complex multi-domain topic of natural classroom ventilation. Full article

Indoor air quality and energy efficiency are instrumental aspects of school facility design and construction, as they directly affect the physical well-being, comfort, and academic output of both pupils and staff. The challenge of balancing the need for adequate ventilation to enhance indoor air quality with the goal of reducing energy consumption has long been a topic of debate. The implementation of mixed-mode ventilation systems with automated controls presents a promising solution to address this issue. However, a comprehensive literature review on this subject is still missing. To address this gap, this review examines the potential application of mixed-mode ventilation systems as a solution to attaining improved energy savings without compromising indoor air quality and thermal comfort in educational environments. Mixed-mode ventilation systems, which combine natural ventilation and mechanical ventilation, provide the versatility to alternate between or merge both methods based on real-time indoor and outdoor environmental conditions. By analyzing empirical studies, case studies, and theoretical models, this review investigates the efficacy of mixed-mode ventilation systems in minimizing energy use and enhancing indoor air quality. Essential elements such as operable windows, sensors, and sophisticated control technologies are evaluated to illustrate how mixed-mode ventilation systems dynamically optimize ventilation to sustain comfortable and healthy indoor climates. This paper further addresses the challenges linked to the design and implementation of mixed-mode ventilation systems, including complexities in control and the necessity for climate-adaptive strategies. The findings suggest that mixed-mode ventilation systems can considerably lower heating, ventilation, and air conditioning energy usage, with energy savings ranging from 20% to 60% across various climate zones, while also enhancing indoor air quality with advanced control systems and data-driven control strategies. In conclusion, mixed-mode ventilation systems offer a promising approach for school buildings to achieve energy efficiency and effective ventilation without sacrificing indoor environment quality. Full article

Poor indoor air quality (IAQ) in schools is associated with pupils’ health and their learning performance. This study aims to provide an overview of the outdoor factors that affect the IAQ in educational settings in order to develop public health measures. We conducted a systematic literature review to investigate the outdoor factors that affect IAQ in educational settings. The selection of articles included 17,082 search string hits from the ScienceDirect database published between 2010 and 2023, with 92 relevant studies selected based on the inclusion and exclusion criteria. Based on a systematic review of the literature, we identified the following outdoor factors: proximity to busy roads, commercial and industrial establishments, meteorological conditions, compounds from the natural environment, emissions from heating buildings, atmospheric reactions and secondary pollutants, unpaved school playgrounds, and smoking. This study provides key information on the mentioned outdoor factors and gives recommendations on measures to reduce classroom pollutant concentrations while highlighting educational settings that require special attention. Our study shows that classroom IAQ is affected by many outdoor pollutant sources, the prevalence of which depends on the educational setting’s micro location. Therefore, it is essential to develop an appropriate classroom ventilation strategy for each educational setting. Full article

Indoor air quality (IAQ) is a crucial priority, especially since people spend most of their time indoors. Indoor air can be more polluted than outdoor air due to sources such as building materials, cleaning products, and heating systems. This condition can affect health and productivity, especially in schools and work environments. Students spend about a third of their day in classrooms, and studies have shown that poor IAQ can cause respiratory and allergic problems, especially among children, who are more vulnerable. Poor ventilation and excessive CO₂ concentration are indicators of suboptimal indoor air quality, which can lead to symptoms such as headaches, fatigue, and worsening asthma. In Italy, the lack of specific legislation on indoor air quality in schools is a problem, but improved ventilation, both natural and mechanical, and monitoring of CO₂ levels are recommended to prevent negative health consequences. This paper aims to describe a methodology to improve IAQ in schools. The paper discusses the results of a study conducted on CO₂ and PM₁₀ levels measured in real time in cold season (Nov–Mar) in different classrooms of primary and secondary schools present in a large Italian urban area in order to understand the IAQ state and identify possible improvement actions. Full article

There are many different factors affecting indoor air quality: environmental ones such as temperature, humidity, human activities within the building, smoking, cooking, and cleaning, but also external pollutants such as particulate matter, biological contaminants, and viruses or allergens. This study investigated the indoor air quality (IAQ) of a primary-school classroom in Cracow, Poland, based only on CO₂ concentration levels exhaled by occupants. In the 1960s, over a thousand schools were built in Poland using similar technology. Most of them are still in use, and in many cases, modernization works are being carried out to improve their building envelope and the comfort of their use. The analyzed school is one of several hundred similar ones in southern Poland. Therefore, analyzing the possibilities of improving IAQ is an important topic, and the results can be used in the modernization process for many other buildings. Measurements indicated that the CO₂ levels significantly exceeded acceptable standards, signaling poor air quality during usage time. This problem was connected mainly with the low efficiency of the natural ventilation system being used in the classroom. It is worth emphasizing that this type of ventilation system is the most commonly used ventilation solution in Polish schools. To address this problem, the classroom environment was simulated using CONTAM software, and the model was validated by comparing the simulated measurement data against the collected measurement data. Next, simulations for the entire heating season in Cracow were conducted, revealing that the IAQ remained consistently poor throughout this period. These findings highlight the persistent problem of inadequate ventilation in the classroom, which can have adverse effects on the health and performance of students and teachers. This article shows the usefulness of CONTAM for modeling not only gravity ventilation but also the window-opening process. The validated CONTAM model will be subsequently utilized to simulate annual IAQ conditions under various ventilation strategies in order to identify the most effective methods for maintaining acceptable IAQ while minimizing energy consumption. In our future analysis, the validated model will be used to test the following systems: demand-controlled ventilation (DCV), exhaust ventilation, and DCV/balanced ventilation with heat recovery. Full article

School buildings are essential in catering to children’s psychological and educational needs. They enable children to learn, teach, play, and interact with peers. The corridor space within a school’s structure is also significant, serving multiple purposes. The community in Erbil, Iraq, has expressed concerns about the economic challenges of constructing and designing new school buildings. Therefore, this research aimed to identify unused spaces in these corridors to ensure usability and flexibility while reducing the cost of building construction. A comprehensive approach was taken to achieve this, employing both qualitative and quantitative analysis techniques. The qualitative analysis was conducted through surveys and documentation to provide an intense understanding of the issues. This research employed two distinct quantitative methods: first, the study used the Revit engineering software to compare the circulation ratio of pre-existing buildings with that recommended by the BB 103 guidelines, and second, student feedback was collected through a questionnaire to provide a holistic view of the situation. This study found that the built-up corridor area in the L-shaped school accounted for 34% of the total area, 11.5 percentage points more than the BB 103 guideline. Meanwhile, the built-up corridor area in the O-shaped school was 20.5 percentage points higher than the recommendation. According to the student feedback, the extra corridor space in the selected schools is not being efficiently utilized. Therefore, the proposed redesigns for the L-shaped and O-shaped schools focus on eliminating traditional corridors and integrating outdoor spaces to create functional areas, enhancing natural lighting and ventilation. These redesigned concepts ensure cost-effective, adaptable, and engaging educational spaces that support the well-being and academic success of students. This paper recommends that school designers and architects re-evaluate existing school designs with a focus on reducing corridor spaces and prioritizing outdoor learning areas. By adopting these strategies, schools can improve space utilization, foster healthier and more efficient learning environments, and promote sustainability. Full article