Indoor Air Quality In Classrooms Research Articles

Assessment of the Bacteriological Properties of Indoor Dust in some Classrooms of Delta State University of Science and Technology, Ozoro

The bacteriological properties of indoor dust in some classrooms of the Delta State University of Science, Ozoro was examined with a view to identify any possible source of pollution of classroom indoor air quality; measurement of microbial load of classroom dust sample and to compare findings of selected locations as a means to determine high air polluted areas. This was done by the collection of dust samples from classrooms table and chair surfaces. It was observed that the amount of bacteria available in classrooms differ based on activities in and around the classrooms. Bacteria isolates indicated the presence of pathogen associated with disease such as Bacillus sp; Staphylococcus sp; Micrococcus sp. of indoor air pollution exist and this is identified as open dump practice birthing more microbial cells which are transported through air and poor sanitation practice around and within the classrooms. Contamination of sample was observed for dust at different locations with the bacteria count seen to be higher at sample C (1.8x102cfu/m3) and lower in sample D (0.2x102cfu/m3). Staphylococcus sp dominated all the locations that were analyzed while Micrococcus sp. only occurred in site C. This is because poor environmental sanitation is observed at certain classrooms in addition to shattered classroom windows given an ease of access of dust flow indoor. It can be concluded that only a minimal sources of indoor air pollution exist and hence only a small amount of bacteria is present. In spite of this, prevalence of such practices is likely to promote the growth of more microbial cells.

Spatial distribution of CO2 Impact on the indoor air quality of classrooms within a University

Indoor air quality (IAQ) remains a public and global concern. While CO2 does not pose health risks to occupants, high CO2 levels indicate insufficient ventilation, potentially accumulating pollutant concentrations. In buildings, occupants are identified as the main source of indoor carbon dioxide (CO2) through exhalation. Standard classrooms may have occupant density between 1.8 and 2.4m2/person. Therefore, the IAQ of classrooms and lecture theatres remain a concern. This study investigated airflow and contaminant (using CO2 as a proxy) distribution in two classrooms modelled using CFX a Computational Fluid Dynamics (CFD) software, verified against experimental measurements. The model provides the visualization of flow patterns so that the effects of external and internal flow fields in the classroom can be studied. The results show that there are large differences in classroom indoor ventilation performance due to the effects of wind direction and wind speed on building surface wind pressure from outdoor wind speeds. Windward high-pressure surfaces and leeward vortices created by building shading promote indoor air quality in buildings with windcatcher openings. The concentration distribution of CO in the classrooms showed an upward convergence with the thermal plume generated by the respiratory differences of the personnel and the temperature of the lighting equipment. The results of this study have important implications for improving classroom design guidelines for school buildings, especially in terms of ventilation strategies and air quality monitoring.

Exposure Assessment of Infectious Virus Particles in a Classroom Setting Using Computational Fluid Dynamics Model

Indoor air quality in classrooms directly affects comfort, focus, and academic performance. This research leveraged Computational Fluid Dynamics (CFD) to analyze the dispersion of infectious virus particles in classrooms. While Negative Pressure Systems (NPS) are often used at medical centers to inhibit virus particles’ dispersion, those are seldom applied in educational settings. The study aimed to pinpoint optimal ventilation and heating/AC flow rates to prevent virus particle spread. Results showed that prioritizing a higher flow rate at the ventilation unit over the heating/AC unit creates a negative pressure differential, decreasing virus dispersion by up to 93%. To establish negative pressure, the minimum flow rate ratio of ventilation to heating/AC should be 1.0. But for maximal virus particle reduction, a ratio of 2.8 is optimal. This research underscores CFD's value in understanding NPS dynamics and simulating virus behavior in classrooms. The findings suggest that NPS implementation in schools could significantly curb virus particle spread.

Indoor acoustic quality of educational buildings in South West Europe: Influence of current ventilation strategies

The quality of the classroom environment has a great impact on the physical and mental health of students and teachers. The COVID-19 pandemic has highlighted the need for new measures and ventilation strategies to be implemented in educational buildings, to ensure indoor air quality in classrooms and to minimise the risk of airborne virus transmission. However, these ventilation protocols can influence the acoustic quality of classrooms and negatively affect students’ speech perception and learning performance. This study presents the results obtained from a field measurement campaign carried out to assess the acoustic characteristics of classrooms of the Fuentenueva Campus (University of Granada) and Azurém Campus (University of Minho). Different ventilation operating scenarios (active and inactive) were assessed to evaluate their impact on the indoor acoustic conditions. The reverberation time (RT), the only parameter used in both countries' regulations to assess acoustic conditions, was found to be higher on both campuses than the RT limits values. Comparison of the measured Speech Transmission Index (STI) and background noise values in the active and inactive ventilation scenario showed a clear variation of the indoor acoustic conditions. The background noise was higher in the active ventilation scenarios (40–57 dBA) than in the inactive ventilation scenarios (34–48 dBA). The average STI values obtained on both campuses for the inactive and active scenarios were 0.54 and 0.51, respectively. In some classrooms an STI difference of 0.1 was found between scenarios. The results obtained in this study provide a broader understanding of the acoustic conditions in university classrooms in Spain and Portugal. The results evidence the need of consider the synergies between the indoor acoustic and air quality conditions to ensure both: the spaces are safe and the acoustic conditions do not interfere with students' learning. The findings show that compliance with the current RT requirements does not ensure that classroom acoustic conditions do not interfere with student performance, and therefore, regulations need to be revised to include additional factors to ensure proper acoustic performance.

Determining ventilation strategies to relieve health symptoms among school occupants

PurposePoor indoor air quality (IAQ) contributing to occupants’ health symptoms is a universal, typically ventilation-related, problem in schools. In cold climates, low-cost strategies to improve IAQ in a naturally ventilated school are rare since conventional methods, such as window opening, are often inappropriate. This paper aims to present an investigation of strategies to relieve health symptoms among school occupants in naturally ventilated school in Finland.Design/methodology/approachA case study approach is adopted to thoroughly investigate the process of generating the alternatives of ventilation redesign in a naturally ventilated school where there have been complaints of health symptoms. First, the potential sources of the occupants’ symptoms are identified. Then, the strategies aiming to reduce the symptoms are compared and evaluated.FindingsIn a naturally ventilated school, health symptoms that are significantly caused by insufficient ventilation can be potentially reduced by implementing a supply and exhaust ventilation system. Alternatively, it is possible to retain the natural ventilation with reduced number of occupants. The selected strategy would depend considerably on the desired number of users, the budget and the possibilities to combine the redesign of ventilation with other refurbishment actions. Furthermore, the risk of poorer indoor air caused by the refurbishment actions must also be addressed and considered.Practical implicationsThis study may assist municipal authorities and school directors in decisions concerning improvement of classroom IAQ and elimination of building-related symptoms. This research provides economic aspects of alternative strategies and points out the risks related to major refurbishment actions.Originality/valueSince this study presents a set of features related to indoor air that contribute to occupants’ health as well as matters to be considered when aiming to decrease occupants’ symptoms, it may be of assistance to municipal authorities and practitioners in providing a healthier indoor environment for pupils and teachers.

Using Active Green Wall Systems for both Saving Energy and Improving Indoor Air Quality in Classrooms

University classrooms in Thailand normally use air conditioners to enhance thermal comfort for building occupants. Classrooms with many students are often found to exceed standard concentration levels of carbon dioxide (CO2). This research aims to study the benefits of active green wall systems in two aspects. They are energy consumption and the ability to reduce CO2 of plants. The green walls in this research are divided into two systems, which are active green wall (AGW) and passive green wall (PGW). The experiments took place in an air-conditioned classroom with ten occupants. The room temperature was set at 25 °C for all experiments. The data collected for all experiments are CO2, temperature, and energy consumption. The results showed that two active green wall panels with a single plant of Epipremnum aureum is the optimal model for improving air quality in classrooms, when compared to other experiments. It can reduce the CO2 concentration by 35% and use less energy than the no green wall experiment at 26%.

Indoor Air Quality in Classrooms Before and During the COVID-19 Pandemic: Lessons Learned from the Health Effects of Lebanese Schools Indoor Environment (HELSIE) Study Study

Indoor Air Quality in Classrooms Before and During the COVID-19 Pandemic: Lessons Learned from the Health Effects of Lebanese Schools Indoor Environment (HELSIE) Study Study

School Children Exposure to Low Indoor Air Quality in Classrooms During Covid-19 Pandemic: Results of a Pilot Study

Background: Indoor air quality (IAQ) in classrooms affects children s health and academic performance. The aim of this pilot study was to determine IAQ in elementary schools different in their internal and external characteristics, in settings of COVID-19 epidemics. Methods: IAQ parameters: fine particulate matter (PM2,5) mass concentration, CO2 concentration, temperature and relative humidity were measured in parallel in four elementary schools/classrooms during October (non-heating season) and four months (including holiday in January) of heating season. IAQ parameters were measured in settings of anti-epidemic restrictions (≤13 students in classroom, frequent ventilation). Results: During October, except in one school, PM2,5 concentrations were below the upper recommended value (25μg/m ), but started rising in all schools in the heating season. The highest concentrations of PM2,5 were registered in two schools with closed or shortly opened windows. CO2 concentrations were mostly in the recommended range (up to 1000ppm) except in the school with constantly closed windows and in three schools in February when concentrations were higher. Except in one, the same school, and in January, both temperature and relative humidity were out of the recommended range (24,0 27,0°C in non-heating;20,0 24,0°C in heating season;and 45 55%), with temperature mainly above and relative humidity mainly below it in three schools. The largest deviation in temperature and relative humidity were registered in urban schools. Registered differences may be explained by different internal and external characteristics. Original paper Conclusion: Despite anti-epidemic restrictions, most of the measured IAQ parameters were out of the recommended values in heating season. In addition, further deterioration of IAQ could be expected if all students had been presented in the classroom. Finally, to assure a healthy school environment in heating season, further optimisation of both indoor and outdoor conditions is needed in both pandemic and non-pandemic settings.

A comprehensive analysis of the intervention of a fresh air ventilation system on indoor air quality in classrooms

Adequate classroom air quality is vital to student health and learning outcomes. Prolonged periods of air conditioner use in enclosed classrooms may result in poor air quality. However, opening classroom windows may expose students to air pollutants if the outdoor air quality is poor. This study investigated CO2 and PM2.5 concentrations in 86 classrooms installed with air conditioners in elementary and middle schools in southern Taiwan, each additionally installed with a fresh air ventilation system equipped with an E11-class filter. Enclosed air-conditioned classrooms generally have a CO2 concentration greater than 2500 ppm; occasionally, this figure reaches 3500 ppm. With the installed air ventilation system operating, the mean classroom CO2 concentration decreased to 1084 ± 203 ppm, and the median CO2 concentration decreased to 1120 ppm. However, the CO2 concentrations of over half the classrooms remained higher than the concentration advised by the World Health Organization (1000 ppm). This high CO2 concentration was a result of the short distance (1.5–2 m) between the indoor air outlet and the recirculated air inlet resulting in a shortened circuit of air travel. Also, the initial filter installed over the indoor air outlet of the system reduced air penetration into the classroom. When the ventilation system was manually activated without activating the air conditioners, the median PM2.5 concentration measured at the indoor air outlet and the median classroom PM2.5 concentration were 2 μg/m3 and 20 μg/m3, respectively. This implied the presence of other sources of PM2.5 in classrooms, particularly ceiling and wall-mounted fans. The activation of these fans spread dust onto classroom furniture. Overall, fresh air ventilation systems providing filtered air improve classroom ventilation efficiency and indoor air quality by reducing CO2 and PM2.5 concentrations, but the cleanliness of fans and furniture must be maintained.

Indoor Air Quality Assessment Inside Secondary Public Classrooms in Jeddah, Saudi Arabia

Classroom indoor air quality (IAQ) can contribute to students’ wellbeing, academic performance, and quality of life. While classroom IAQ field assessments are regularly conducted globally, they are limited in the Kingdom of Saudi Arabia (KSA). Initiatives driven by Saudi Vision 2030 point toward improving IAQ conditions in classrooms and led to the development of enhanced pilot school models. This study assesses classroom IAQ in conventional and pilot secondary public schools in Jeddah using CO2 concentration levels as a commonly used indicator for comparing IAQ and ventilation performance. CO2 levels were measured in 12 classrooms (N = 12) that used different mechanical conditioning systems in three schools. The results revealed that all the examined classrooms reported high levels of CO2 concentrations in excess of the recommended 1,000 ppm by ANSI/ASHRAE Standard 62.1, which was mainly due to classrooms being overcrowded, the type of mechanical conditioning system, and students’ behavioral patterns and operational schedules. More practical guidance on the provision of fresh air and the efficiency of mechanical ventilation systems is required to ensure adequate ventilation and pollutant dilution.

Impact of design parameters of diffuse ceiling ventilation systems on indoor air quality in school classrooms: a numerical assessment

Indoor air quality directly impacts an individual’s productivity and health condition in office buildings, hospitals, schools, and residential buildings. Diffuse ceiling systems have been used widely in classrooms at schools that have high heat loads. In this regard, this study investigated the role of diffuse ceiling design parameters, including active diffuse panels’ configuration and contamination locations, on indoor air quality in a classroom. The spread of airborne infectious diseases was simulated using computational fluid dynamics techniques. The results revealed that the central configuration of diffuse ceiling panels had the minimum spread of contaminations in the classroom compared to the dispersed configuration.

Effect of Air Purifier Use in the Classrooms on Indoor Air Quality—Case Study

Dissatisfaction with indoor air quality is common even in relatively new or renovated Polish school buildings. To improve air quality in educational buildings, portable devices have seen increased use, for which manufacturers guarantee a high level of indoor air purification. However, their optimized operation largely depends on their correct use. The aim of this article was to determine the effectiveness of air purification in a primary school using an air purification device with an analysis of the classroom indoor air quality (IAQ). Two criteria were used, microbiological and particulate matter concentration. Measurements were made before device installation and during its continuous operation, and before and after lessons on chosen days. Measurements related to IAQ did not detect clear differences in the analyzed measurement periods. For microbiological contamination, in the morning before lessons, the total count for all bacteria and microscopic fungi was definitely lower than after lessons. Comparing the periods before and after device installation, no clear tendency for reducing the bacteria count or microscopic fungi occurred during air purifier operation, nor was there any noticeable trend in the reduction of particulate matter. There was no improvement in air quality in the classrooms during the operation of the purification devices.

INVESTIGATION OF IMPROVING INDOOR AIR QUALITY METHODS AT EDUCATIONAL INSTITUTIONS PROVIDING SERVICES FOR CHILDREN WITH DISABILITIES IN VIETNAM

Indoor air quality has a significant impact on the health and working efficiency. There are studies on indoor air quality and the effect of indoor air quality on young children around the world and also in Vietnam. However, several studies have have not evaluated indoor air quality in classrooms at educational institutions that provide assistance to children with disabilities. As a result, the article focuses on investigating methods to improve indoor air quality at educational institutions providing services for children with disabilities, based on theoretical and practical studies on air quality; expert and teacher opinions on the feasibility and readiness to implement methods to improve air quality at intervention facilities for children with disabilities. The survey has 151 people that took part in it. The findings indicate that teachers in both inclusive and special schools have a basic grasp of classroom indoor air quality and its influence on children with disabilities. Teachers in specialized schools, on the other hand, rated classroom indoor air quality substantially worse than teachers in inclusive institutions. Furthermore, they highlighted steps done by their institution as well as additional innovative but particular ideas for improving classroom indoor air quality for children with impairments. Because this is a relatively recent problem in Vietnam, more methods to enhance classroom indoor air quality at educational institutions that provide services for children with disabilities are required.

A study on students’ perceptions of air pollution, particulate matter, and indoor air quality in classrooms

A study on students’ perceptions of air pollution, particulate matter, and indoor air quality in classrooms

Indoor air quality in the primary school of China—results from CIEHS 2018 study

Indoor air quality ((IAQ) in classrooms was associated with the daily exposure of school-age children who are particularly vulnerable to air pollutants exposure, while few data exist to evaluate classroom indoor air quality nationwide in China. The subsample of the CIEHS 2018 study was performed in 66 classrooms of 22 primary schools nationwide in China. Temperature, relative humidity, PM2.5, PM10, CO2, CO, formaldehyde concentrations, bacteria and fungi were detected in all classrooms by using the instruments that meet the specified accuracy. The ratios of indoor to outdoor (I/O) of PM2.5 were calculated in each classroom to identify whether the indoor environment the pollutants comes from outdoors. The indoor PM2.5, PM10, CO, HCHO, bacteria and fungi GM concentration are 47.40 μg/m3, 72.91 μg/m3, 0.37 mg/m3, 0.02 mg/m3, 347.51 CFU/m3 and 362.76 CFU/m3, respectively. We observed that there were 66.5%, 52.6%, 22.4%, 1.8%, and 9.6% of the classrooms that exceeded the guideline values of PM2.5, PM10, CO2, HCHO, and bacteria, respectively. It should be attention that all of the classroom's PM2.5 concentrations in Shijiazhuang and Nanning, PM10 concentrations in Nanning, CO2 concentration in Lanzhou were exceeded the suggested values. Bacteria contamination in Shijiazhuang's classrooms is also serious. All classroom CO concentrations meet the requirement. The results indicated that classroom indoor PM2.5 was significantly positively correlated with indoor PM10 and CO2, while was negative correlated with temperature, CO, and fungi. Our results suggest that indoor air pollution in classrooms was a severe problem in Chinese primary schools. It is necessary to strengthen ventilation in the classroom to improve indoor air quality. What's more, a healthy learning environment should be created for primary school students.

Improving Indoor Air Quality in Classrooms via Wind-Induced Natural Ventilation

Student performance in classrooms is related to the indoor environmental quality. High air change rates are necessary to secure an acceptable level of indoor air quality and provide fresh air, which require large amounts of energy and technical installations. Mostly, mechanically supplied air is partially mixed with the return air. In warm climates, the capacity for natural ventilation is not fully exploited in modern buildings. During periods of acceptable outdoor temperatures, buildings need to adapt and employ available free renewable resources, such as wind. In this context, the building form, orientation, and envelope openings are crucial to enable an increased air change rate, user satisfaction, and energy savings. Owing to the difficulty of providing cross-ventilation in buildings with double-loaded corridors, single-sided ventilation is the most common approach. This study investigates the methods to improve the wind-driven air exchange of classrooms in warm climates, where naturally ventilated corridors help increase air movement. This study examines the potential of a set of alternatives within the context of a generic model regarding the pressure distribution, thermal sensation, air velocity, and air change rate. The study suggests that no single opening scenario can be applied to all façades at any time. Each façade requires special treatment. Decisions on natural ventilation need to be made during the early design stages for each façade. It was found that with the aid of low-tech modifications, remarkable increases in air change rates, in some cases up to 14.5 times that of the typical single-sided ventilation case, could be achieved.

On the potential of demand-controlled ventilation system to enhance indoor air quality and thermal condition in Australian school classrooms

Indoor thermal comfort and air quality in school classrooms are of interest worldwide, primarily because of their potential impacts on students’ health, learning performance and productivity. Further, increasing concerns with changing climate and building energy efficiency highlight the importance of ventilation and comfort in educational settings. The existing literature on indoor air quality (IAQ), ventilation, and thermal comfort in classrooms in subtropical regions of Australia is sparse. Here, we present the results of a field study conducted in secondary school classrooms in Sydney during the school year in 2018 and 2019. We collected data with subjective surveys through questionnaires and with field measurements related to IAQ the thermal comfort in two adjacent similar classrooms. The infiltration and ventilation rates were measured during the non-occupied period using the concentration decay method. We analysed the performance of a cloud-connected demand-controlled mechanical extract ventilation system (DCV), which was installed in one of the two surveyed classrooms during mid-season. Before application of the DCV, CO2 levels were similar in both classrooms with a maximum concentration of approximately 2418 ppm during cold season. The DCV reduced the peak CO2 concentration to 1335 ppm, while CO2 raised to 2981 ppm in the classrooms without DCV during mid-season. Further, Volatile Organic Compounds (VOCs) analysed from air samples show improved air quality in the classroom with DCV. Our results highlight the impact of both indoor temperature and CO2 concentration on students’ feeling of fatigue. Students showed adaptability to indoor temperature change. A period of one week is needed for students’ adaptation to a step change in the mean outdoor temperature. Understanding classroom indoor air quality and thermal environment, as well as students’ perceived comfort, is vital to develop child-based design guidelines for schools.

Study of the measured and perceived indoor air quality in Swedish school classrooms

The influence of a classroom’s indoor environment on children’s health, performance and comfort is a concern that receives increasing attention. Many schools experience problems with inadequate indoor air quality and climate. Investigations of the indoor air quality (IAQ) in schools have been often non-systematic, which can lead to costly ad-hoc remediation actions. It is therefore important to develop a holistic approach to the assessment of IAQ in schools.This paper presents a field study on the indoor air quality and thermal environment conditions of elementary schools in Gothenburg, Sweden. The focus of the paper is on the methodology to investigate the IAQ using both objective measurements and subjective assessment of the perceived IAQ. The indoor environmental measurements include indoor air quality and thermal comfort parameters for which guideline values exist. Finally, a questionnaire was developed to evaluate the perception of the classroom’s thermal environment and air quality by young children.The paper presents the study protocol and diagnostics approach for IAQ in classrooms. Examples of results from the first 10 investigated classrooms are presented.

Simulation study for natural ventilation retrofitting techniques in educational classrooms – A case study

Building retrofitting plays a critical role in achieving sustainable development and is an efficient way to improve the indoor air quality (IAQ) of existing spaces. The IAQ in classrooms has a significant impact on the health and academic achievement of students. However, improving the IAQ of existing classrooms is challenging if minimum architectural modifications are allowed. Different natural ventilation retrofitting techniques were proposed to improve the IAQ in existing classrooms at Jordan University of Science and Technology, which is located in a hot arid region. Computer simulations were used to analyze the ventilation rate, indoor operative temperature, relative humidity, and CO2 concentration in the base Case classroom and after the implementation of the proposed retrofitting techniques. Simulation results were compared with those obtained in the base case to determine the most efficient natural ventilation retrofitting technique. The best results were obtained by using a solar chimney to assist a wind tower, which resulted in an increase in the comfort hours during the occupation time, an improvement in the average monthly ventilation rate range, a decrease in the CO2 concentration, and an improvement in the relative humidity ratio. An energy-saving of 39% would be achieved compared with the use of split unit air condition systems. Economic assessment of the proposed system using net present value indicates positive economic viability.

An Assessment of Indoor Air Quality and Thermal Comfort in Educational Spaces (Case Study: Girls' High Schools in Arak, Iran)

As s tudents spend one-third of their time at school, their health, comfort, and productivity are mos tly influenced by thermal condition and indoor air quality of classrooms. Regarding that manual windowopening is a common way for providing fresh air in classes and s tudents aren't allowed to change their uniform, position or control the windows during the lesson hours, providing thermal comfort in winters may cause a lack of fresh air and therefore, dissatisfaction. This article is trying to evaluate the indoor air quality, and thermal condition of the classrooms, in two typical classrooms for 15-16-year-old girls in Arak, Iran. The overall s tudy objective is to compare indoor microclimate measured parameters, with (1) s tudents' subjective judgment, collected through a ques tionnaire, and (2) s tandards and to inves tigate the effects of microclimate on the indoor environmental condition of classrooms. According to the results, the thermal sensation of the s tudents depends on their clothing rate and their unders tanding of the thermal s tate. In contras t, their thermal satisfaction is affected by the amount of fresh air provided. In winter, because of closed windows, s tudents are mos tly dissatisfied with the air quality and, therefore, thermal comfort, while in spring that the indoor environmental conditions meet the s tandards; the s tudents feel satisfied with the conditions. The results of this research show that the indoor environment of the classrooms is mainly influenced by internal loads; consequently, its thermal condition is not a defining parameter.