Indoor Air Quality (IAQ) in Educational Institutions: A Review on Risks of Poor IAQ, Sampling Strategies, and Building-Related Health Symptoms (original) (raw)

Iman Fitri Ismail 1, a* { }^{1, \text { a* }}, Alif Izzani Zainol Adnan 1, b { }^{1, \text { b }}, Abdulrahman Mohammed Qaid Al-Mekhlafi 1, c { }^{1, \text { c }}, Belal Abdelkarim Mahmoud Abdelkarim Mohamed 1,d{ }^{1, d}, Nurul Fitriah Nasir 2, e { }^{2, \text { e }}, Azian Hariri 2,†{ }^{2, \dagger}, Norasikin Mat Isa 2, g{ }^{2, \mathrm{~g}}
1{ }^{1} Faculty of Mechanical Engineering and Manufacturing, Universiti Tun Hussein Onn Malaysia, Parit Raja, Batu Pahat, 86400, MALAYSIA
2{ }^{2} Centre for Energy and Industrial Environment Studies (CEIES) Universiti Tun Hussein Onn Malaysia, Parit Raja, Batu Pahat, 86400, MALAYSIA
*Corresponding Author
Email: ∗†{ }^{* \dagger} ifitri.ismail@gmail.com, b { }^{\text {b }} izzani250496@gmail.com, c { }^{\text {c }} veenx@live.com, d { }^{\text {d }} belal.mahmoud294@gmail.com, e { }^{\text {e }} fitriah@uthm.edu.my, f { }^{\text {f }} azian@uthm.edu.my, g { }^{\text {g }} sikin@uthm.edu.my

Received 01 January 2020; Accepted 10 February 2020; Available online 20 March 2020

Abstract: Health and academic achievement of students from every level of education are affected by the provision of good Indoor Air Quality (IAQ) since the students spend more than 5 hours of a day in school on average. Hence, this paper discusses on issues related to IAQ studies in maintaining a healthy level in educational institution. The presence of indoor pollutants such as VOCs, CO2\mathrm{CO}_{2}, and other hazardous elements were assessed in terms of its effects on students’ well-being and health. This paper also examines commonly reported health problems related to poor IAQ such as sick building syndrome (SBS) and asthma. Every measurements and consideration regarding IAQ provision comes with different techniques and strategies, which were highlighted regarding its relative importance and frequency of use by different researchers. The review suggested substitution of natural-based products for indoor cleaning agents and installation of air ventilation and purification systems for a more acceptable indoor air quality.

Keywords: IAQ, indoor air quality, education, students, review

1. Introduction

Indoor air quality (IAQ) is air quality around the space or building or structure. It seems to be a concern on the effects of indoor air pollution on health, the comfort and also wellbeing of the occupant inside a building or indoor space.[1] Many reasons are affecting the IAQ, which is the infiltration of the outdoor and indoor pollutant such as dirt, soil, smoking and a few others cause of pollutant. As stated in the paper, the studies by the Environmental Protective Agency of United State, it reveals that the pollution level for the indoor is higher by 100 times compared to the outdoor levels [1]. Next reason that can affect the indoor air quality is the weather condition in certain countries such as the desert climate country, they need to confront with the dust particles that are going to come into the indoor space as people walk through the doors. Other than that, educational facilities also one of the most polluted indoor premises as there is higher occupant density. It is to be
the highest pollutant concentration due to the movement of the pupils around the buildings. IAQ also may affect the performance of the student and teachers [2].

1.1 IAQ Measurement

The indoor air quality has its standards to consider the impact on the public [3]. Evaluation of the indoor air quality is by measuring the particle matter concentration. The particulate matter (PM) is the values that are to be used for evaluating the concentration. PM10\mathrm{PM}_{10} is particulate matter that are sizes for 1.0 micrometer in diameter. It is not usually use for assessment because the size is already as small as the gasparticle that are used for breathing. Evaluation of IAQ commonly being made by measuring PM2.5\mathrm{PM}_{2.5} and PM10.PM2.5\mathrm{PM}_{10} . \mathrm{PM}_{2.5} and PM10\mathrm{PM}_{10} are particulate matters that are smaller than 2.5 and 10 micrometers in diameter respectively. For a building that are in the area which PM2.5\mathrm{PM}_{2.5} exceeded, particles filter or air

[1]


  1. *Corresponding author: ifitri.ismail@gmail.com 2019 FAZ Publishing. All right reserved. ↩︎

cleaning device should be provided to clean the outdoor air at any specific location before it goes into occupied spaces. The air cleaner shall have minimum efficiency report value (MERV) that not less than 11 as rated following ASHRAE standards 52.2 [4]. For PM10\mathrm{PM}_{10}, buildings that are in an area where the national standards are exceeded, should provide air cleaning filters or particles filters at specified spaces before it starts to introduce to occupied spaces. The MERV should not be less than 6 as stated in ASHRAE standard 52.2 [4]. Besides particulate matter, other parameters for evaluation are the air composition such as carbon monoxide (CO), carbon dioxide (CO2)\left(\mathrm{CO}_{2}\right), polycyclic aromatic hydrocarbon (PAHs) and few others. For CO, National Institute for Occupational Safety and Health (NIOSH) has estimated a recommended exposure limit of 35 ppm . The American Conference of Governmental Industrial Hygienists (ACGIH) has put a threshold for CO with a limit value of 25 ppm for an 8 -hour workday. For carbon dioxide, the average outdoor concentration is 300-400 ppm, but it is different when it comes to indoor which is higher. CO2\mathrm{CO}_{2} give effect to human health at 7000 ppm . Therefore, ACGIH has set the occupational limit to 5000 ppm TLV-TWA (Threshold Limit Value - Time Weighted Average (usually 8 hours)) and 30000 ppm TLV-STEL (Threshold Limit Value - Short Term Exposure Limit (usually 15 minutes)) [10].

Besides, for outdoor respirable suspended particulate matter (RSPM) level, it does consider the size, occupancy level, temperature, relative humidity and CO2\mathrm{CO}_{2} concentrations. To evaluate the IAQ for each test need to be done 7-8 hours to get a good result. Other parameters that are used for evaluating IAQ is by measuring the concentration of formaldehyde, benzene, trichloroethylene, pinene, limonene, NO2\mathrm{NO}_{2} and O2\mathrm{O}_{2}. Other than that, the parameter that will be recorded is the temperature, relative humidity and ventilation rate [5]

1.2 Recent advancement of IAQ

The implementation of acceptable IAQ for university building is not widely discussed, but several universities have started to implement good IAQ requirement. The importance to evaluate indoor air pollution is greater than the outdoor level. Because 90%90 \% of peoples spend their time indoors [6]. A university from the Czech Republic, had conducted a study to find a sufficient indoor air quality environment for learning purposes. This is due to the weather condition where the windows and doors are usually closed causing the IAQ inside a building is not at good condition [7]. Another university also had implemented study on IAQ and thermal comfort for the transition season [8]. All these universities conducted study on IAQ in order to find their best way to get a good environment so that pupils will have potential to stay focus in classes. Next important of doing IAQ assessment is to find the recognizable impacts on the health and welfare of the population.[6] Besides, by assessing the indoor pollution level, it is also to implement corrective measures to improve air quality. For some reason, the IAQ assessment is also to demonstrate the effect of internal quality on performance and productivity [7]. This shows that different university has a different mission on assessing IAQ which mostly to improve their working condition and learning environment.

There are several ways the IAQ study is done. Based on paper from indoor air quality in Brazilian university, it uses field test method which they have selected 30 rooms. The air condition (AC) 15 rooms and natural ventilated (NV) 15 rooms to run the test. For this experiment, the parameters that have been considered were indoor CO2\mathrm{CO}_{2}, temperature, relative
humidity (RH)(\mathrm{RH}), wind speed, viable mold and airborne dust concentration. The assessment is done by taking samples between 1 February and 30 March 2006 during summer. It is collected between 9 am to 11 am from Monday to Friday. The study is done at five universities in Brazil which 4 of it in the suburbs area and one in the central area. The data collected is about 1290 or each study with 43 samples for each classroom. Table 1 shows the characteristic of monitored sites.

Table 1 - Characteristics of monitored rooms

Monitored Description
University A Located in a suburban area Surrounded by residences and industries Use of a blackboard and chalk Built in the 70s Presence of vegetation nearby
University B Located in a suburban area Surrounded by residences and buildings Use of a blackboard and chalk Built in 2000 No presence of vegetation nearby
University C Located in a suburban area Surrounded by residences and buildings Use of blackboard with chalk Built in the 70s No presence of vegetation nearby
University D Located in a central area Surrounded by residences and buildings Use of a blackboard and chalk Built in the 70s Presence of vegetation nearby
University E Located in a suburban area Surrounded by residences and buildings Use of a blackboard and chalk Built in the 90s No presence of vegetation nearby

Michal and Petra [7] conducted IAQ assessment by giving survey form and use ASHRAE thermal comfort scale to evaluate the condition of the classes before nd after using the class. Another assessment is done by Wu et. al [8] using field measurement and questionnaire survey. The field measurement was done through onsite measurements which the parameter is temperature, relative humidity (RH),CO2(\mathrm{RH}), \mathrm{CO}_{2} PM2.5\mathrm{PM}_{2.5}, formaldehyde and TVOC. It is done from 8 am to 10 pm at the library with data recorded for every 2 hours from the equipment. They also use optical light spectrometer (BGPM02) to measure the PM2.5\mathrm{PM}_{2.5} particles. For the questionnaire, it was adapted from Sweden study on health-relevant exposure and was modified to actual condition in China.

Even though IAQ level and the emission of air pollutant are investigated, there is still room to be considered on having the same result due to a lot of factors such as the environment, temperature, the room condition and even the climate of the region. Different region in the world will provide different result for each test, as can be seen for the four-season region and hot climate region. Most of the university or the institution, considered on the impact of the student. This is because the student will spend the most time inside the classroom. It can be said that about 70%70 \% of student life will be spent inside the classroom [9].

2. Indoor air pollutants and hazards

2.1 VOCs and the risk on early, primary, and secondary educational institution

Health and safety of students in institutional settings affect their academic performance as they are exposed to the different pollutants and indoor air hazards especially spending a significant amount of time per day in their education buildings. Children in school especially spend most of the time in a single classroom, a study has been conducted in Brisbane over 25 primary schools to identify the sources of volatile organic compounds (VOCs) and its effect via principal component analysis with varimax rotation. It is deduced that 41%41 \% of indoors VOCs was caused by the usage of cleaning products as shown in Fig 1. The study suggested the use of natural-based products for cleaning agents, stop using air fresheners and proper storage of arts and crafts items [10].
img-0.jpeg

Fig. 1 - Source of indoor VOCs in Brisbane classrooms

In the United States, a study conducted over 144 classrooms in 37 elementary schools has detected a high concentration of toluene, benzene, m-xylene, n-hexane, and dilimonene with a median concentration of 0.3 to 3.5μ g/m33.5 \mu \mathrm{~g} / \mathrm{m}^{3}. Hence, an inspection of the classrooms and school buildings have determined the VOC sources from cleaning products, paints, air fresheners and outdoor industries. IAQ can be improved by increasing ventilation rates [11]. A similar study has been conducted in Minnesota over 15 schools, which determined notable level of p-dichlorobenzene that poses several health risks to children in schools [12]. While in Michigan, examination over 64 classrooms have provided an assessment of the VOCs and bioaerosols levels. Via monitoring and surveys that have been conducted, it has been observed that localized IAQ problems with VOCs such as the bioaerosols contamination and CO2\mathrm{CO}_{2} are due to poor ventilation [13]. It is noted that children have higher sensitivity of health responses to pollutants compared to adults, yet most of the
children spend a significant number of hours in educational environments that are exposed to dangerous levels of indoor pollutants. Over investigation of eight naturally ventilated Italian schools, VOCs level was recorded for a week with the presence or absence of students via diffusive samplers for thermal desorption. The location of the chosen schools was selected in such a way to emulate the variation of urbanization and traffic density to analyze the risks of exposure in different urban areas. High terpene concentration has been determined from the monitoring of all classrooms with α\alpha - pipene and limonene within range of 6.55 to 34.18μ g/m334.18 \mu \mathrm{~g} / \mathrm{m}^{3} and 11.11 to 25.42μ g/m325.42 \mu \mathrm{~g} / \mathrm{m}^{3} which poses carcinogenic health risks to students [14]. For early childhood education (ECE) environment, 38 VOCs have been measured in a single day of sampling over 34 ECE facilities. It is determined that cleaning and personal care products as the main perpetrators in the peak of indoor concentration of d-limonene and decamethylcyclopentasiloxane. This study prompts for more research on exposures of benzene, chloroform, naphthalene and ethylbenzene and their long term effects on the risk of cancer among children [15]. In Aveiro, Portugal, efforts have been made to identify the different organic and inorganic pollutants within the school buildings. The study simultaneously evaluates the comfort parameter such as temperature, relative humidity, and carbon dioxide CO2\mathrm{CO}_{2}. The sampling detected a higher than acceptable level of bioaerosol and CO2\mathrm{CO}_{2} that exceeds maximum values of occupant comfort such as shown in Fig. 2 [16].
img-1.jpeg

Fig. 2 - Carcinogenic activity for indoor classrooms in different urban areas.

On a tertiary education level, the effects and sources of VOCs exist in a different form since the activities associated with higher educations no longer confined by the classroom walls. Therefore, the role of humans in contributing to the production of indoor VOCs remain scarce. To mitigate the issue, continuous measurements of VOCs have been made using Positive matrix factorization (PMF) to figure out the human factor of the VOC components such as human respiratory products and skin lipids ozonolysis. The research derived that 40%40 \% of the measured daytime concentration of VOC came from human components of VOCs Therefore, it is deduced that the indoor environment oxidative capacity is significantly affected by human [17].

Research and development activities within the campus become one of the primary contributors of VOCs in university campuses around the globe. A research on the contribution of campus R&D activities on the surrounding air quality was assessed by measuring the VOCs emitted from the rooftop fume hoods. Concentrations of VOCs produced by laboratory buildings are higher than non-laboratory buildings. Therefore, the suggestion on the installation of an air purification system within the ventilation system was made to reduce the effect on atmospheric pollution [18]. When it comes to arts and crafts

activities, indoor chemical emissions of the university arts center were made via a 6-week study on the VOCs level using the box model to aid the quantification of air composition rate. It is determined that unsaturated and saturated VOCs have oxidation lifetime of more than 15 hours. Therefore, an implementation of indoor gas-surface partitioning was proposed to control the level of organic pollutant within the arts center for the respiratory health of visitors and the conservation of arts [19].

Concerning the presence of hazardous compounds, the presence of 34 types of VOCs was measured in Middle East Technical University in Ankara. Samples were taken both in summer and winter, it was observed that the concentration of VOCs in winter is higher due to poor ventilation during the winter months. Traces of solvent that evaporated from the research laboratories were also a contributor to the indoor VOCs in the university [20]. Even though it is rarely studied in educational facilities, tobacco smoke was a dominant contributor to indoor pollution as observed in the Department of Physics and Electrical Engineering of the University of Bremen. While other pollutants are associated with the biproducts of cleaning agents such as aldehydes, monoterpenes, and acetone such as shown in Fig. 3. Correlation between human activities is strengthened by the spike of VOCs during workdays [21].
img-2.jpeg

Fig. 3 - Concentration of VOCs according to location based on human activities.

A study conducted in a new campus in Tianjin, China has revealed that anti-freeze materials as the main contributor to the level of ammonia that is 100%100 \% more than the allowable level at 0.28mg/m30.28 \mathrm{mg} / \mathrm{m}^{3}. Among Ammonia, Alkenes was found to be the most significant in the campus dormitories and contributed to 86.5%86.5 \% of concentration of VOCs. It is observed that the Alkenes originated from the wardrobes that have been installed in the new campus [22]. In sports facilities such as gymnasium, monitoring of indoor VOCs was obtained via spectrophotometry, high-performance liquid chromatography and gas chromatography with ionization detection. The study determined Acrolein as the most significant carbonyl compounds which originated from cleaning products. Minimum ventilation rate also affected the amount of recorded indoor VOCs. The use of chalks also contributed to the high level of particles in the gymnasium [23].

2.2 Effects of IAQ on the well-being and academic of students

The conditions of the indoor environment influence human health, productivity, and comfort. Although the measurement of IAQ in classrooms have been widely reported, only fews are relate to the effect on student’s performance and well-being. It has been correlated that a
reduction of attendance and learning potential might be due to the poor classroom IAQ. One of the early studies regarding poor IAQ and student’s performance-linked concentration of CO2\mathrm{CO}_{2} with student performance via a survey. The result obtained exhibited a significant ( P<0.10\mathrm{P}<0.10 ) association of the ventilation rate and math test results. Hence, nonlinear effect studies are suggested to properly present the association and better conclusion can be drawn via larger sample size [24]. In India, academic satisfaction of students was determined by studying the contributing factors such as perceived indoor environmental quality (PIEQ). Six factors of indoor environment quality (IEQ) for conducive learning have been identified such as furniture, daylight, adaptive opportunities, thermal and IAQ aspects. The observation was made on the perceived importance of indoor environmental quality (PIIEQ) as the most influential factor [25].

Since poor IAQ is usually affiliated with Sick Building Syndrome (SBS), the performance and productivity of students are usually affected by the indoor pollutants. This can be observed based on how high concentration of CO2\mathrm{CO}_{2} resulted in reduced concentration and causes fatigue [26]. Poor IAQ is known as the cause for mild adverse events such as nausea, headaches and respiratory problems, but recommendations given to UNESCO Chair on Health Education and Sustainable Development has documented on how poor IAQ affected student attention span and academic performance [27]. Research in Netherland has concluded on how poor IAQ affected the performance and attendance of the students particularly due to the effect of indoor pollutants on their health [28]. The effect of ventilation rate and the influence posed on perceived indoor air quality (PIAQ) relates how learning processes, concentration and productivity are affected by the ventilation rate [29].

In the effort to improve the condition of air quality in school, a quasi-natural experiment has been conducted in Texas school district that discovered how the improvement of IAQ responded in an improvement of standardized test performance while attendance remains unchanged. This is correlated by the budget spent on ventilation and roof treatment and the increased in the standardized test performance via standard deviation as shown in Fig. 4 [30].
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Fig. 4 - Treatment of roof effects on standardized test performance

2.3 Sickness and disorder commonly reported

Illnesses caused by poor IAQ are continuously researched and backed by evidence as it requires students to be absent from schools for respiratory-related health problems. Sick build syndrome (SBS) have been reported according to students in schools with poor IAQ [31]. One study compares ventilation performance and associates the level of pollutants to Sick Building Syndrome (SBS) symptoms. Increasing the rate of ventilation (VR) can alleviate SBS symptoms while improving IAQ [32]. Effects of poor IAQ and IEQ are present and categorized as symptoms of SBS, such as cold, headache, confusion, dizziness, eye irritations, fatigue, nausea, and respiratory problems. The poor IAQ is usually complemented by poor IEQ that generally contributes to SBS among students as shown by a survey conducted in Taylor’s Universiti, Malaysia [33]. The relationship is strengthened by the study conducted among students of educational institution in Kuala Lumpur and Selangor [34].

Traffic-related air pollution has been associated with the poor cognitive development of students, especially in primary school students as observed in 39 schools in Catalonia, Spain. This is due to the polluting agents of elemental carbon (EC), ultrafine particle number and nitrogen oxide that impairs students cognitive development as observed using the attentional network test [35]. Air pollution around schools also affects the student’s health due to increased risk of respiratory, neurological disorder and even cancer problems. The chemicals in the air such as lead and manganese have a deteriorating effect on brain functioning which causes poor cognitive developments [36]. The respiratory problem such as asthma is also aggravated due to air pollution at school. This can be observed by the study of asthmatic onset and trafficrelated pollution at home and schools which recorded a high level of Nitrogen Oxide (NO2)\left(\mathrm{NO}_{2}\right) which contributes to the development of asthma [37]. The previous studies are backed by the study of traffic-related air pollution (TRAP) and its implication in asthmatic development. The study also highlights the epigenetic mechanism of asthma which aids in the strategical intervention of combating asthma among school children [38]. Cancer risk of school children was determined in Xi’an, China which studied the cancer risks of polluting elements such as Arsenic, Cobalt, Chromium, and Nickel which exist as particulate in the air and present close to school children. The concentration of the elements is shown in Fig. 5 as the cancer-causing elements which have been recorded in schools in Xi’an [39].
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Fig. 5 - Concentration of cancer-causing metals in different schools of Xi’an

3. Measurement and analysis of IAQ parameters

3.1 Sampling strategy and techniques

A sampling of air quality in school environments concern with the concentration of many indoor air pollutants that been measured which include CO2,O3,NOx,CO\mathrm{CO}_{2}, \mathrm{O}_{3}, \mathrm{NO}_{x}, \mathrm{CO}, and VOCs and PM. Hence, thus are used as the main characteristics for the assessment of IAQ in schools [40][41][1][3]. While in primary schools in Lisbon, formaldehyde is also collected in the 2,4dinitrophenylhydrazine in sampling cartridges reacted to give the corresponding 2,4-dinitrophenylhydrazones [42][43]. Therefore, to cover all possible parameters of IAQ in schools and educational building, total airborne bacteria were reported in range varies from 7 to 19500CFU/m319500 \mathrm{CFU} / \mathrm{m}^{3}, also dust mite and fungi were measured [44].

Many types of research are focused on measuring of air temperature and relative humidity, or conducting a questionnaire as they are one of the main contributors in IEQ which affect student’s satisfaction, performance in their study and attention span [45][46]. Additionally, an adequate inspection by researchers has been done to monitor and examine the mechanical ventilation system attached in the facilities to measure fungal or organic dust contaminant in cooling coils and condensate trays [47][48]. Dirty filters or rotten parts are checked as they lead to air pollution problems [49].

Including questionnaire or survey form to students in the assessment and data collecting process beside the major measured parameters gives the researchers a closer sight on how comfort, satisfied, and healthy are the students and how they interact with the existed ventilation system and the indoor environment surrounding them. Hence, it is an indicator of whether IAQ is sufficient or have a problem [50][51][2]. Finally, total particulate matter (TPM) measurement was conducted in spring, autumn and winter using a passive method where a total of six 47 -mm diameter Millipore polycarbonate filters were exposed in classrooms in the largest city of Portugal Lisbon, distributed over a tray with an area of 25 cm×20 cm25 \mathrm{~cm} \times 20 \mathrm{~cm}, at 120−cm120-\mathrm{cm} high to approximate the breathing height of children inside the classrooms [52].

3.2 Analysis of data at various institutional buildings

The data analysis has been taken differently over the study cases yet, there are major parameters that have been measured in most of the study cases such as CO2\mathrm{CO}_{2}, temperature, and the related humidity. A case study conducted in Brazilian universities to compare the indoor air quality between airconditioned (AC) and naturally ventilated (NV) classrooms. Chemical, physical and biological methods have been used to calculate the CO2\mathrm{CO}_{2}, temperature and relative humidity. The levels of CO2\mathrm{CO}_{2} in the AC rooms were significantly different from the NV rooms 1433.62±252.801433.62 \pm 252.80 and 520.12±37.25520.12 \pm 37.25 ppm ), in both AC and NV classrooms, respectively. The temperature was stabled between 25−28C25-28 \mathrm{C} with humidity of 56%56 \% to 65%65 \%. The study shows that the difference in CO2\mathrm{CO}_{2} level between AC and NV classrooms is significant where AC classrooms have less CO2\mathrm{CO}_{2} level. The indoor air quality in the universities classrooms in Brazil affects the health of students, and this reason is enough to consider indoor air pollution as an important public health problem[6].

Most of the schools in cold weather countries such as French have a natural ventilation system only. A case study conducted in eight different schools to measure a chemical measurement of NO,NO2,O3\mathrm{NO}, \mathrm{NO}_{2}, \mathrm{O}_{3} and I/O\mathrm{I} / \mathrm{O} ratios. As the result the found out the levels is 0.98ppm,0.93ppm,0.28ppm0.98 \mathrm{ppm}, 0.93 \mathrm{ppm}, 0.28 \mathrm{ppm} and range between 0.03 - 1.79 respectively[53]. There are other cases

used physical measurements using Bruel & Kjaer Hand-held Analyzer to value the rate of the IAQ by the temperature and thermal comfort. As a result, 24c24 c and 166 ICT respectively were the outcomes of the measurements [54].

Working or studying in a comfortable environment enhances not only wellbeing but also satisfaction and therefore productivity and learning. This is the reason for the study case conducted in Italian primary schools. It focused on the level of CO2\mathrm{CO}_{2} in the air, the temperature, and its related humidity. 3635ppm,20.5∘C3635 \mathrm{ppm}, 20.5^{\circ} \mathrm{C} and 58%58 \% was the result respectively [55]. The low rate of IAQ in the buildings affect the breathing system of people with asthma disease [56]. For example, in Saudi Arabia, the weather in some months in the year is dusty because of the sand hurricanes where the building must do non-natural ventilation. A study case in a university hospital has been made to find the level of NO2,O3,CO,SO2\mathrm{NO}_{2}, \mathrm{O}_{3}, \mathrm{CO}, \mathrm{SO}_{2}, Temperature and its RH. The result was 0.00154ppm,0.02110.00154 \mathrm{ppm}, 0.0211 ppm,0.55ppm,0.0908ppm,22.2∘C\mathrm{ppm}, 0.55 \mathrm{ppm}, 0.0908 \mathrm{ppm}, 22.2^{\circ} \mathrm{C} and 37.9%37.9 \% respectively. The instrumentation tool that was used is the Kestrel 4500 instrument. They found out the Non-Natural ventilation is effective for desert climate [57]. There is also a study case on a desert climate of school building air quality. The chemical tests were used by 90 -degree optical light scattering Photometer and Photo Ionization Detector EVM-7 to find the level of CO2\mathrm{CO}_{2}, temperature, and its RH. The result was at a range between 1182.2 to 2134.6ppm,14.32134.6 \mathrm{ppm}, 14.3 to 24.6∘C,3424.6^{\circ} \mathrm{C}, 34 to 74%74 \% respectively [33].

Some case studies made by chemical and physical measurements such as case study conducted in Portuguese schools to find the level of bacteria and the fungi level in the surface of the classroom. The 73 classrooms monitored in 20 public primary schools located in Porto showed generally low levels of VOCs and aldehydes, acceptable ranges of temperature and humidity, but often high levels of CO2,PM2.5\mathrm{CO}_{2}, \mathrm{PM}_{2.5} and PM10\mathrm{PM}_{10}. According to the results, Formaldehyde exceeded the acceptable limit and the total fungal count was within the acceptable limit in the meanwhile the bacteria acceded the acceptable limits by more than 2200. The result of the paper shows low rates of ventilation, which might be explained by the reduced airing of the classrooms which underlines the influence of indoor sources, occupant behavior and maintenance, cleaning activities in schools and the high density of occupants [58]. There is a difference in results between the tests conducted in the winter and in the summer. 64 schools in the city of Munich in Germany and a neighboring has been studied. The measurements conducted in winter 2004-2005 in 92 classrooms, and in summer 2005 in 75 classrooms. The level of CO2\mathrm{CO}_{2}, temperature and RH in the winter is 890ppm,22∘C890 \mathrm{ppm}, 22^{\circ} \mathrm{C} and 25%25 \% respectively. Where in the summer, the results of thestudy are 1759ppm,25∘C1759 \mathrm{ppm}, 25^{\circ} \mathrm{C} and 38%38 \%, respectively. The measurements conducted by laser aerosol spectrometer (LAS) and scanning mobility particle sizer (SMPS). The result shows that during winter, the CO2\mathrm{CO}_{2} levels are low and within the acceptable range but during summer, it exceeds the acceptable range by over 800 ppm [59]. A case study of indoor air quality in a classroom in the UK with natural ventilation has been conducted using a roof-mounted split-duct Windcatcher ventilator to find out the level of the CO2\mathrm{CO}_{2}. The study shows that the level of CO2\mathrm{CO}_{2} is changing between the winter and the summer in a range of 869-1459 ppm [60].

Surveys and questionnaires are among the method to collect health and domestic exposures data. A questionnaire has been conducted to 38 schools and completed by 1410 people and its 85%85 \% of the total people numbers. The chemical and physical measurements were conducted by glass fiber

6
filters impregnated and liquid chromatography. The result of CO2,NO2,CO\mathrm{CO}_{2}, \mathrm{NO}_{2}, \mathrm{CO}, temperature and RH was arranged of 425 to 2800ppm,1tol1ppm,0.12800 \mathrm{ppm}, 1 \mathrm{tol} 1 \mathrm{ppm}, 0.1 to 0.9ppm,19.50.9 \mathrm{ppm}, 19.5 to 27.5∘C27.5^{\circ} \mathrm{C} and 16−16- 75%75 \% respectively. They found out there is a relationship between the answers in the questioners and the result of the chemical and physical measurements [61]. Another case study by surveys and questionnaire were conducted in dense Academic Building in Universiti Tun Hussein Onn Malaysia. The aim of the surveys and questioners are to find out the IEQ while a chemical and physical measurements conducted by using Statistical Package for Social Science (SPSS) to find the level of CO2\mathrm{CO}_{2}, temperature and RH. The result of the chemical measurement was 513ppm,23∘C513 \mathrm{ppm}, 23^{\circ} \mathrm{C} and 73%73 \% respectively, and as the previous study they found out a relationship between the questioners and the chemical test [62]. Most of the schools that have been tested have a high level of CO2\mathrm{CO}_{2} which is above 1000 ppm , and it is unacceptable by the standard. This is a common problem between most of the schools and universities [63]. An investigation of the indoor air quality has been made at urban schools in Qatar. The information was collecting by survey and two portable Q-Trak monitors model 7575-X; TSI Inc., Shoreview, MN, the USA as a measurement tool. The CO2\mathrm{CO}_{2} result is a range between 887 ppm and 1776 ppm . The CO level was between 0 ppm and 1.2 ppm . The temperature and RH were a range of 18.8 to 25.2∘C25.2^{\circ} \mathrm{C} and 42.8 to 61.3%61.3 \%. Finally, the indoor-outdoor ratio (IO) was in a range of 3.89 to 2.03 [64].

A case study studied the relationship between the students learning performance and the indoor environmental quality (IEQ) in air-conditioned university teaching rooms. The study shows reveals that all IEQ complaints have a similar impact on learning performance and there is a good correlation between learning performance and the number of complaints. The information was collected by a survey. There is also a measurement of CO2\mathrm{CO}_{2}, temperature and RH. There result is 492 to 1627ppm,19.91627 \mathrm{ppm}, 19.9 to 25.1∘C25.1^{\circ} \mathrm{C} and 40.2 to 71.3%71.3 \% [65].

The data have been recorded from different cases of studies in a different country. The data as shown in Table 2 shows that most of the educational buildings in having a stable temperature in a range between 20∘C20^{\circ} \mathrm{C} and 24∘C24^{\circ} \mathrm{C}, in the meanwhile there is a significant difference on the level of CO2\mathrm{CO}_{2}

yet, most of the cases result have acceded 1000ppm which is not acceptable.
concentration and fatigue. It also causes health problems to the student as sick building syndrome (SBS), respiratory problems

Table 2 - Data collection from fifteen case studies in different countries.

Referenc e/ Data \begin{aligned} & \text { Referenc } \\ & \text { e/ Data } \end{aligned} CO2 (ppm) \begin{gathered} \text { CO2 } \\ \text { (ppm) } \end{gathered} NO (ppm) NO2 (ppm) \begin{gathered} \text { NO2 } \\ \text { (ppm) } \end{gathered} T∘C\begin{gathered} \mathrm{T} \\ { }^{\circ} \mathrm{C} \end{gathered} RH%\begin{gathered} \mathrm{RH} \\ \% \end{gathered} I/O ICT O3 (ppm) \begin{gathered} \text { O3 } \\ \text { (ppm) } \end{gathered} CO (ppm) \begin{gathered} \text { CO } \\ \text { (ppm) } \end{gathered} SO2 (ppm) \begin{gathered} \text { SO2 } \\ \text { (ppm) } \end{gathered}
[47] NV NR NR NV NV NV 1.08 NR NR NR NR
520.12 28.87 65.00 AC 0.45
AC AC AC
1433.62 25.87 56.21
[48] NR 0.98 0.93 NR NR 0.03 -1.79 NR 0.28 NR NR
[49] NR NR NR 24 NR NR 166 NR NR NR
[50] 3635 NR NR 20.5 58 NR NR NR NR NR
[24] 922-1185 NR NR 22.1-23.2 3 NR NR NR NR NR
[51] NR NR 0.00154\begin{gathered} 0.0015 \\ 4 \end{gathered} 22.2 37.9 NR NR 0.0211\begin{gathered} 0.021 \\ 1 \end{gathered} 0.55 0.0908\begin{gathered} 0.090 \\ 8 \end{gathered}
[52] 1182.2−2134.6\begin{gathered} 1182.2- \\ 2134.6 \end{gathered} 0.3 0.2 NR NR NR NR NR NR NR
[53] 829−3111\begin{gathered} 829- \\ 3111 \end{gathered} NR NR 14.3−24.6\begin{gathered} 14.3- \\ 24.6 \end{gathered} 34-74 NR NR NR 0.01−1.70\begin{gathered} 0.01- \\ 1.70 \end{gathered} NR
[54] 890−1759\begin{gathered} 890- \\ 1759 \end{gathered} NR NR 22-25 25-38 NR NR NR NR NR
[56] 425-2800 NR 1-11 19.5-27.5 16-75 NR NR NR 0.1-0.9 NR
[57] 513 NR NR 23 73 NR NR NR NR NR
[58] <=1000 NR NR 20-24 30-70 NR NR NR 0 NR
[60] 492-1627 NR NR 19.9-25.1 40.2-71.3 NR NR NR NR NR
[55] 869-1459 NR NR NR NR NR NR NR NR NR
[59] 1776-887 NR NR 18.8-25.2 42.8-61.3 3.89-2.03 NR NR 0.0-1.2 NR

4. Conclusion

Based on the papers reviewed, concern with the safety and health of students in educational facilities has become crucial as it is noted that they sensitive to pollutants than adults. Indoor environment considerably affected by capacity and human components of VOCs came out of the body. Variety of time and places that students go through during their existence in schools or institution make them vulnerable to numerous kinds of pollutants exposure. Hence, increasing in VOCs concentration is detected in winter and cold weather due to insufficient ventilation. Several places expose students to indoor air pollution, biproducts in cleaning agents which used in classrooms, gymnasium, and laboratories. Research labs that contribute to indoor VOCs with solvent evaporation and using anti-freeze material which is the main source of ammonia. Tobacco smoke although it slightly mentioned it has a huge contribution to indoor VOCs and air particles. Finally, sports facilities share in indoor pollutants from acrolein originated from cleaning products and chalks used there. Student health, performance, productivity, and cognitive process all affected by IAQ of the educational facility. Reviewing showed that some factors increase student satisfaction with the institution and increasing his attention span such as furniture, daylight, and thermal and IAQ aspects. While poor IAQ and ventilation system lead to high CO2\mathrm{CO}_{2} concentration which linked to a reduction in student
like asthma, and may cause cancer by the existed pollutants particles in the air so children may expose to. Air pollution around schools also affect student health, so it is essential to study the surrounding for any traffic or industrial emissions. According to research and studies conducted in the reviewed papers, IAQ in educational facilities is monitored and evaluated to determine its parameters and recorded health problems. Therefore, toward achieving a better and cleaner environment for students’ activities some recommendations are suggested. To reduce the effect of air pollution, air purification system can be installed within the ventilation system to achieve better air quality and increase indoor ventilation rates. Substitute bi-products with natural-based products for cleaning agents which are commonly used. And to control the level of organic pollutant, it is recommended to implement an indoor gas-surface partitioning. Conducting more studies and research is needed for further knowledge and understanding of the IAQ, IAQ measurement, and development of assessment and sampling techniques. Sufficiently study the effect of IAQ and IEQ on children and student’s performance, well-being growth, and cognitive process.

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