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Traditional building are built to suit the climate, the users and their surroundings. One of the famous traditional building in Malaysia is Masjid Kampung Laut, a public mosque that located in Nilam Puri, Kelantan, Malaysia. This building is an iconic building as still standing and fully utilised while its age is 400 years old. This study aims to investigate the factor of good indoor air quality (IAQ) in Masjid Kampung Laut, and to prove the hypothesis that it was because of the cross ventilation system within the building. The methodology used in the investigation is mix method, involving several ways including measurement on site, interview, direct observation, participant observation, and physical artifact. The intention of this study hereby to make an awareness among the core players in building industry such as architects, designers, developers, engineers and the authorities to preserve our traditional buildings, at the same time take traditional design as the model to make a better design that suit our culture and climate. As conclusion, we conclude that traditional buildings was built excellently understand the climate, promotes cross ventilation to ensure the Indoor Air Quality (IAQ) in optimum condition. [ABSTRACT FROM AUTHOR]

In the current work numerical and experimental study are conducted to investigate the flow behaviour and thermal comfort in climate-controlled conference hall situated at University of Anbar. In the first part of the study, numerical investigation is conducted to understand the impact of the air conditioning supply and extracts openings locations on the physical characteristics of the air flow within the conference hall. Moreover, the study investigates the optimal location of the air conditioning units within the system. In this work the main emphases are to study the flow dynamics of the air and the thermal behaviour inside the conference hall with large number of audiences inside it. Typically, the efficiency of an air flow system is evaluated by the successful removal of sensible and latent loads from the system under control. In addition, to maintain the level of air pollutant at a prescribed accepted level to assure the optimal human thermal comfort conditions. This will improve the indoor air quality and the thermal comfort for the audience which is the main goal of the present study. The numerical part of the study is carried out using computational fluid dynamics (CFD) simulation approach. To attain this part, commercially available CFD software ANSYS\Fluent is used. The numerical modelling techniques solved the continuity, momentum, and energy conservation equations. The k – ε model is used to tackle the turbulent nature of the flow studied in this case. The second part of this study is achieved by measuring the velocity, air temperature and relative humidity experimentally by means of the calibrated instruments. The validation of the used approaches is carried out through comparing the attained numerical and experimental results. Good agreement is found between the numerical and experimental predictions obtained during the present work. [ABSTRACT FROM AUTHOR]

Proper indoor air quality and thermal comfort ensure healthy indoor environment where people live and work. The measurements in the paper were performed in the public utility, smart building as known "Energis" located on the campus of Kielce University of Technology (Poland). A group of student volunteers took part in the study. The anonymous questionnaires were used to assess their thermal sensations, preferences and acceptability before and after the lecture. At the same time carbon dioxide level, air and ambient temperatures, relative humidity as well as air velocity were recorded using the Testo 400 microclimate meter. The relationship between the changing air parameters throughout the one hour period of measurements, together with the test results from the questionnaire survey provides information on the possibility of providing high thermal comfort and indoor air quality in the smart buildings, which are still quite rare throughout the world and especially in developing countries like Central and Eastern Europe. The analysis of the obtained results showed that, despite the increase in CO2 in the room, the students felt better at the end of the class than at the beginning. No other sources of discomfort were observed during the test (rising temperature, draft, too warm or light clothing, etc.). [ABSTRACT FROM AUTHOR]

Buildings are places where indoor air quality, moisture and temperature should be controlled at the specified levels. Indoor CO2 contaminants as one of the indoor air quality parameters that can be generated by residents' breathing and the initial concentration of outdoor air can be measured. Another issue that buildings have these days is the moisture, specifically in humid climates. The high humidity can increase the risk of mold growth in the building envelope at the meantime can reduce the thermal comfort conditions. In order to increase the performance of a building in the fields of indoor air quality and moisture, field-testing along with modeling tools should be used. With the help of modeling tools, the available values of indoor air quality, moisture and temperature measures can be predicted and then the strategies for controlling their quantitative values can be analyzed. In this context, two methods have been used to analyze and predict the indoor air quality, moisture and thermal comfort measures. In the first method, the CONTAM single model is used to calculate indoor air quality and WUFI is used to calculate moisture performance and thermal comfort. In the second method, an integrated model that coupled CONTAM and WUFI is developed. In the integrated model, all three measures of indoor air quality, moisture performance and thermal comfort are calculated. Indoor CO2 is assumed as a measure for indoor air quality, indoor relative humidity is assumed as measure of moisture performance and predicted percentage of dissatisfied (PPD) is assumed as measure of thermal comfort. A three-story house has been selected for the location of Vancouver, BC, Canada. The two scenarios of airtight fan off and airtight fan on are assessed in order to compare the simulation results in both single models and integrated model methods. [ABSTRACT FROM AUTHOR]

Proper indoor air quality and thermal comfort are part of the healthy indoor environment. The tests performed in the public utility, intelligent building „Energies" of Kielce University of Technology (Poland) with a group of students are the focus of the paper. The anonymous questionnaire survey was used to determine their thermal sensations, preferences and acceptability before the lecture and after it. In the meantime CO2 level, air and globe temperatures, relative humidity and air velocity were measured with the Testo 400 microclimate meter. The comparison of the changing air parameters throughout the time of 1.2h with the questionnaire survey provides information on the possibility of providing high thermal comfort and indoor air quality in the intelligent buildings, which are still quite rare in Central Europe. Consequently, obtaining experimental data there is valuable and important. It turned out that the building did not provide good quality parameters during the study, because the people felt too warm or hot in the room and wanted to change the temperature to a much cooler environment. What is more, the assessment of air quality according to the students at the beginning of classes at relatively low CO2 contents turns out to be an interesting phenomenon, where 36% of students subjectively assessed it in their questionnaires as being unacceptable. [ABSTRACT FROM AUTHOR]

The global haze problem is becoming increasingly prominent, and indoor air pollution is becoming more and more serious, resulting in an increase in the number of patients with "sick building syndrome" living in closed rooms. Under the bad indoor and outdoor air environment, scholars from various countries have actively explored the use of indoor plants to purify the air. Windows are not only a channel for the exchange of air between indoors and outdoors, they are also a channel for outdoor pollution to enter the house. By integrating plants with windows and using trace irrigation technology, the author designed and built a maintenance-free plant window device - Green Window System (GWS). This paper introduces the detailed structure, irrigation technology and plant screening of the GWS.9 experiments were set up to compare the absorption capacity of indoor and outdoor particulate between the GWS and the same amount of indoor plants under the same conditions. The study found that under indoor air circulation conditions, the GWS adsorbed 1.3% and 1.71% more PM2.5 and PM10 respectively than ordinary plants. Under indoor and outdoor ventilation conditions on a hazy day, the PM2.5 and PM10 in the room with the GWS were 26.53% and 40.18% lower respectively than in an ordinary room, indicating that the GWS is more effective in adsorbing PM2.5 and PM10, and proving that the GWS is more effective in purifying PM10 than PM2.5. The green window system saves space in the room and enhances the photosynthetic efficiency of the plants. The GWS creates closed airtight ducts and a more humid environment that facilitates the adsorption of plants and the settling of particles. [ABSTRACT FROM AUTHOR]

The design and layout of office space is one of the fundamental factors influencing the indoor environmental quality and thus also the performance and satisfaction of the users themselves. The paper deals with the evaluation of selected indoor environmental quality (IEQ) factors, specifically thermal comfort and indoor air quality (IAQ) parameters, in two office buildings. Both buildings are identical in terms of design and technical equipment, they differ in the design of the layout. While the first office building consists of closed office spaces, the second has an open-space layout. Measurements of selected IEQ risk factors were carried out on different floors in selected office spaces representative of all occupied areas under typical operating conditions. The results of real measurements show that the office rooms of both office buildings meet the criteria set by the legislation. In addition, the requirements set by the internationally recognized LEED and WELL certification systems were also met in both buildings. Based on the results of measurements of thermal comfort and indoor air quality parameters can be concluded that, spaces in both buildings provide their users with a healthy and comfortable working environment. [ABSTRACT FROM AUTHOR]

In the development of construction industry, it is necessary to maintain the quality of indoor air at a higher lev-el, preventing a decrease in the energy efficiency of heat supply for construction projects. Indoor air quality is character-ized by the composition of the building's indoor air environment. The creation of specified conditions is possible with a set of technical means: built-in air source heat pumps with forced ventilation and modern devices for analyzing air purity. The use of additional funds to improve air quality will increase the cost of developing design work. Taking these re-quirements into account when designing the production of works will lead to a rise in cost by 13%, however, the rational-ization of the planning scheme of the design process for low-rise buildings will allow this solution to remain competitive. Improving the indoor climate of the premises will have a positive effect on the well-being and working capacity of the people in it, therefore, a slight increase in the cost of developing design work can be considered justified. [ABSTRACT FROM AUTHOR]

The paper presents a bind of ways to improve indoor air conditions in the basement premises of the restored and reconstructed historical buildings. The features of the functional purpose of these basements are given and connected with religious architectural traditions of Russia. The measures are affecting the indoor air quality in the premises and building envelope conditions. [ABSTRACT FROM AUTHOR]

Since the widespread spread of the SARS and SBS (Sick Building Syndrome) viruses in a building's air conditioning system, there has been a recent emphasis on enhancing Indoor Air Quality (IAQ). Proper air ventilation requires a system capable of balancing the energy requirements and air quality. A liquid dryer air cooling system is an alternative to conventional air dehumidification technology, it may improve air quality and decrease its primary energy consumption. Consequently, a crossflow liquid desiccant dehumidification system is investigated in this study. The experiment's structured packing consists of a cooling coil with finned tubes. Where ionic liquid flows vertically from top to bottom through the cooling coil, while air flows horizontally in a cross-flow configuration, and water flows inside the tube. Lastly, the effect of varying solution inlet condition flow rate and air is presented on system performance. [ABSTRACT FROM AUTHOR]

The need of a clean indoor environment has received a lot of attention in recent years as a result of the rise of diseases and viruses around the world, and acceptable indoor air quality and maximum thermal comfort are particularly essential markers of passenger comfort. This research focuses on resolving indoor air quality (IAQ) issues in office environments, as well as analysing the principle of the influence of occupant density under mixing ventilation on office room thermal comfort. Two office rooms were simulated under a mixing ventilation system using the program ANSYS 15.0 (ICEPAK). The relative humidity, air temperature distribution, carbon dioxide concentration (CO2) and thermal efficiency were numerically estimated for each room and a comparison was made between the two rooms to show the effect of the diffuser type on the comfort of the occupants. Three tests were conducted for each room, depending on the number of persons in the room (3,4,6 persons). The air supply temperature and flow rate of the two rooms differ according to the heat acquired from the external environment, where the air temperature and flow rate (19.8 oC) and (0.45 m3/s), respectively, were recorded in the office room (under-linear slot diffuser), while in the office room (under-round ceiling diffuser) were the air supply temperature and flow rate (16 oC) and (0.1766 m3/s), respectively. The results of the tests found that the indicators of thermal comfort (ADPI), (PPD), (PMV) improves with reducing the number of person in the room. When comparing the two rooms, the results show that the office room (under-round ceiling diffuser) gives better indicators of thermal comfort than the office room (under-linear slot diffuser). In the present office area, the air distribution efficiency of the (MV) system using round ceiling diffuser was an average of (10%) greater than a similar system utilizing linear slot diffuser; this disparity reduces by around (2%) with each increase in the number of persons. [ABSTRACT FROM AUTHOR]

In this paper, Indoor Air Quality monitoring based on the non-dispersive infrared (NDIR) used as an optical method of detecting gases. The Co2 concentrations measured in indoor environments surrounding the human beings by a Portable CO2 Detector (CH016Q-BriSunshine). Four tests achieved on several locations such as: places of worship (the mosque), meeting room, transport car, the primary schools. For the first indoor environment (Mosque), the highest gas concentrations around (1400 ppm) with closed air vacuums. This result controlled to reach (750 ppm) concentrations for a period of time 33 minutes in the presence of two air vacuums. The second environment (meeting room) requires only one vacuum to reduce the highest gas concentration from (1800 ppm) to (750 ppm) within 40 minutes. As for the third and most important environment (the school), the fluctuating rise in CO2 emission between (800-1500 ppm). After 23 minute from opening the first window, the highest gas concentrations decreased to (950 ppm). Also, the gas ratios rise rapidly resulting from the increase in students' movement during break time. As for the last environment (the car), Co2 emission rise to (4500 ppm) with an average FWHM time of 18 minutes which is bad the air quality, it can be treated through small air vents or opening one of the car windows. It is noticed a decrease in Co2 gas concentrations and a remarkable speed. The importance of the obtained results used to solve the problem of the Co2 direct impact on human health through monitoring air quality small systems. [ABSTRACT FROM AUTHOR]

This paper treats monitoring and predicting the indoor radon activity concentration level in a ventilated room using the Lattice Boltzmann Method (LBM), which is a numerical technique derived from the kinetic theory for simulating fluid flows and modeling fluid physics. Four different configurations of ventilated square cavities have been investigated. The numerical results confirm that the indoor radon activity concentration is affected by the ventilation rate and the location of the outlet. Hence, excellent indoor air quality needs to decrease the indoor radon activity concentration, which requires increasing the ventilation rate and placing the air outlet in a suitable position. [ABSTRACT FROM AUTHOR]

In Malaysia and many other Asian nations where rice is the principal crop, rice straw is routinely burned openly after harvesting. Open biomass burning of crop leftovers is a typical practise that emits a substantial amount of air pollutants which has serious implications for indoor air quality, public health, and climate change. As a result, emissions from open rice straw burning may contribute significantly to local air pollution levels. Most Malaysian farmers are unaware of the numerous alternatives for managing rice straw, and thus believe that burning is the best option. This necessitates massive awareness campaigns to educate farmers about the availability of economically viable options and the cumulative effects of rice straw burning. The articles in this review were chosen based on predefined criteria and demonstrated that the biological and chemical components of particulate matter that are emitted from the rice straw burning activities. [ABSTRACT FROM AUTHOR]

Designing a multipurpose auditorium is challenging since it must accommodate conversation and music functions. Meanwhile, in the COVID-19 pandemic era, well-ventilated rooms and air circulation are essential. However, problems will arise when an auditorium is designed with high ventilation rates, both natural and mechanical. Both natural and mechanical ventilation are significant room noise sources. This paper demonstrates research steps to evaluate auditorium performance that emphasizes healthy indoor air quality apart from good acoustic quality. An ideal auditorium should be located in a noise-free location. This ideal condition is not always situated. If environmental noise becomes an issue, a noise propagation study should be conducted. This research used primary SPL data that was collected in June 2021. 2D mapping software is used to process noise data in the UGM campus area. Results showed that the Auditorium has the potential for 62 – 65 dBA level environmental noise intrusion. This paper recommends design approach to create a building with low-risk COVID-19 transmission. [ABSTRACT FROM AUTHOR]

Green buildings play a strategic role in making an essential contribution to sustainability by increasing energy efficiency, improving indoor air quality, and treating effective waste. However, the implementation of green buildings will be much more effective if the community participates and collaborates in implementing the green building concept in the built environment. The level of community involvement is likely to be influenced by green building literacy, which can be implemented through formal and informal education. Therefore, this study was conducted to determine the literacy level of green buildings in Indonesian society, especially among undergraduate students who will later play a significant role in the transition towards massive green building implementation in Indonesia. In order to determine the green buildings literacy, a framework based on the cognitive, affective, and behavior domains is used. We surveyed 466 students across Indonesia from various universities and then analyzed them by gender, year of study, and the type of university (private or public). The results indicate that the cognitive level is still low, where about two-thirds of the participants show a lack of knowledge of green building and expertise related to green building. Nevertheless, 78.2% of participants wish to seek more in-depth information about green buildings, especially to design their own houses, share knowledge about green buildings through their social media, and be involved in organizations that campaign to implement green buildings. The result of correlation analysis implies that behavior is the most important domain compared to cognitive and affective domains. Based on this finding, green buildings literacy can be done in the realm of formal and non-formal learning, with an emphasis on providing a strong behavioral understanding so that the public can participate in the implementation of green building in the future and explore the cognitive domain more deeply. [ABSTRACT FROM AUTHOR]

Hospital has a high risk of disease transmission because they are a gathering place for healthy and sick people. Indoor air quality in hospitals is different from other work environments because it has its complexities, so it must be considered because it impacts workers, patients, and visitors. The surgery room is a very high-risk category, especially in Health Care-Associated Infections (HAIs) transmission. The surgery room must have ideal environmental conditions such as healthy, safe, and comfortable. This research aims to measure the indoor air quality of surgery rooms in hospital X, Bogor, West Java. This research was conducted using quantitative methods with a cross-sectional approach. The research data were obtained by making field measurements and observations. The results show that the indoor air quality in the surgery room below standards for airborne bacteria, temperature, and humidity, while the lighting still fulfills the standards. Therefore, it is necessary to conduct routine sterilization and disinfection evaluations by the hospital. [ABSTRACT FROM AUTHOR]

Many people spend most of their time indoors. However, not many buildings in Indonesia have an Indoor Air Quality (IAQ) monitoring system that provides IAQ information to their residents. Furthermore, the available IAQ monitoring systems do not consider indoor personal thermal comfort and are difficult to understand since they do not based on any standard measurement. This study aims to design a low-cost Enhanced IAQ Index (EIAQI)-based monitoring system that measures temperature, CO2 concentration, and dust concentration in an indoor environment. The sensors are selected based on the price and availability in the market. The proposed system converts the measurements to EIAQI before transmitting them to a cloud-based ThinkSpeak for visualization and data analytics. This conversation to EIAQI requires a least common multiple of reading time from all sensors. After the system calibration, the testing results using a measurement chamber indicate that the proposed monitoring system provides easy-to-understand IAQ information while enabling the personalized thermal comfort adjustment at the indoor room level. This system is an Internet of Things-based IAQ monitoring system. It provides EIAQI data not only at a room or a house level but also aggregated EIAQI data at schools, universities, and office level. [ABSTRACT FROM AUTHOR]

To solve the problem of indoor air quality, a compact gas-discharge generator with plasma electrodes based on surface discharges has been developed and tested. The generator has a low aerodynamic drag and may be integrated into modern ventilation systems. The gas-discharge generator has a wide range of energetic impact on gaseous media due to the excitation of surface discharges and the assisted bulk discharge. A germicidal effect for air flow purification is observed at the flow velocity V=6-7mps and anode voltage U=+10kV. Under these conditions, the ozone concentration produced by discharges doesn't exceed 170 µg/m3 at the distance of 1000 mm from the gas-discharge generator. [ABSTRACT FROM AUTHOR]

Data on acoustic, thermal, indoor air quality, and lighting conditions have been collected from 220 classrooms in the midwestern United States. Gathered acoustic data include sound levels logged every 10 seconds and room impulse responses from which reverberation times were extrapolated. K-means clustering was used to group the logged sound data into times when speech was or was not occurring; then acoustic metrics were calculated from the clustered data. When comparing the measured acoustic conditions to ANSI S12.60, 91% of the classrooms did not meet the recommended maximum background noise level for unoccupied conditions, while 15% did not meet the recommended maximum reverberation time. The field measurements also revealed that only 20% of the classrooms met ASHRAE Standard 62.1 ventilation rate requirements, while all classrooms met recommended IES illuminance level for reading and writing. Multivariate linear regression analyses between the environmental conditions and student achievement data, while controlling for student demographics, have identified a number of significant relationships. This presentation summarizes key results, describes how acoustic conditions were correlated to building mechanical systems, and considers how indoor environmental quality may be optimized to benefit occupants in educational settings. [ABSTRACT FROM AUTHOR]

Being comfortable and healthy in one's home is of the utmost importance and a contributing factor to the quality of their life, and it is greatly affected by the air quality of the residence. Therefore, the subject of this paper centres around the indoor air quality (IAQ) of a standard household in central Athens and how these components influence human health. The air quality assessment is conducted using particulate matter (PM) on-site continuous measurements taken from low-cost sensors (PurpleAir) installed both inside and outside the house. Focusing especially on PM2.5 data from September 2021 to September 2022, the Air Quality Index (AQI) and the number of exceedances are evaluated in detail, investigating the association between indoor and outdoor environments. [ABSTRACT FROM AUTHOR]

Indoor Radon is the second cause of deadly lung cancer and is suspected of inflicting further health risks and synergies with other air pollutants. Radon mapping is based on long-term average concentrations, but the spatiotemporal concentration variability can be very high, delivering higher radiation doses than expected. Continuous monitoring, appropriate indices, and reliable models, aided by digital technologies may improve the assessment and management of indoor Radon risk, especially for vulnerable populations. Further epidemiological studies, research and modelling in dosimetry, new monitoring technologies and methods, and synergies with air quality research, are expected to contribute towards a unified strategy for Radon risk assessment, management, and perception. [ABSTRACT FROM AUTHOR]

Indoor air quality (radon, pollution, thermal fatigue, ventilation) is crucial for health and performance, especially for children. It is necessary to increase public awareness about the significance of air quality, particularly radon. Environmental school networks can enhance public awareness and provide research opportunities for scientists. SINDAIR, a school network based on SIMA-AEP, provides a flexible platform for larger scale educational and research projects. SINDAIR is in its pilot phase, involving various schools around Greece. With the assistance of UniWA, SINDAIR has started a pilot radon measuring campaign. Preliminary results show increased radon concentrations in certain school rooms, higher than expected, justifying further radon risk and air quality assessment, management, and perception programs. [ABSTRACT FROM AUTHOR]

The high amount of energy consumption in residential buildings can considerably be reduced by adopting passive design strategies (PDS), for its positive impact on the environment by reducing energy consumption and CO2 emissions, cost savings and provide occupants' comfort. This paper summarized the outcomes from a structured literature review. Five broad types of PDS were identified, targeting reduced energy consumption, improved comfort, indoor air quality and materials used. The study also revealed sets of motivators and challenges for adopting PDS. The most common challenges to adopting PDS are high initial cost, lack of expertise and lack of rules and regulations. Also, it was found that the key motivators to stimulate the adoption of PDS include energy efficiency, financial benefits and occupant comfort, health and well-being. This will form the basis for exploring the degree of benefits of considering certain PDS features in residential buildings and their consequent selection/use in specific climate zone, with relevant adjustments to incorporate any local context and priority. The outcomes of this paper are also expected to contribute to raising awareness among stakeholders to increasingly practice PDS considering their relevant benefits, and gradually move to their adoption. [ABSTRACT FROM AUTHOR]

The poor indoor air quality inside the cabin of a coach can be due to indoor air pollutants or to inadequate ventilation. Exposure to surrounding airborne particulate matter inside a long hour journey may increase health risk of the coach passengers. In this study, a one-minute gaseous (carbon monoxide (CO), carbon dioxide (CO2)), physical parameters (relative humidity, airflow, temperature), coach speeds, and number of occupants' data were gathered two days trips for each route travelled coaches via motorways and local routes. The Route 1 journey started from Terminal Kota Bharu (TKB) to Terminal Bersepadu Selatan (TBS) and Route 2 link between Terminal Kuala Terengganu (TKT) and Terminal Bersepadu Selatan (TBS). Data were analysed to understand variability of the variables by using R software and its packages were applied temporally and statistically. An advance and a computational intelligence technique named the Boosted Regression Trees (BRT) was used to examine Relative Variable Importance (RVI) and estimation the Strength of Interaction Effects (SIE) inside cabin coaches. Results demonstrates significant variation in PM10 are distance (39.19%), elevation (15.19%) temperature (10.56%) humidity (6.65%) for Route 1 and 46.7% for CO (13.77 %), humidity (8.92 %), and elevation (8.01 %) for Route 2. It was found that strength of interactions (SIE) index was determined for humidity and temperature for both routes which range between 0.23 to 0.32, followed by humidity and airflow interactions (0.05) and CO and airflow (0.18) for Route 2. Since SIE or H-values fall within range from 0 to 1 which value of zero indicates that there are no interactions between the variables, the interaction between variables will be stronger if the value is closer to 1. It appears and promises that this machine learning method in particular BRT is able to examine in cabin pollutants and physical environment data. [ABSTRACT FROM AUTHOR]

A healthy indoor environment is becoming an increasingly important issue. As the use of various materials in inhabited interiors increases, so does the concentration of harmful volatile organic compounds (VOCs) in these spaces. The actual trend of reducing energy consumption in buildings, such as by using perfectly sealing windows and doors, contributes to this increase. Consequently, people moving around in these interiors experience a rise in health problems due to the elevated concentrations of VOCs. This study aimed to assess the indoor air quality (IAQ) in naturally ventilated primary schools located in the southern Czech region. Two classrooms were selected from each primary school based on similar characteristics, such as building construction, volume, windows structure, area of windows, number of occupants, activities, type of furniture, and internal covering including flooring, wall, and ceiling. The classrooms were continuously occupied during school hours for a total of 25-35 hours per week and unoccupied during afternoons and weekends. The study focused on measuring the concentrations of volatile organic compounds (VOCs) in the classrooms, as well as assessing their impact on health. The study highlights the importance of monitoring IAQ in naturally ventilated primary schools and can be useful for policymakers and school administrators in developing strategies to improve IAQ and promote the health and well-being of students and staff. [ABSTRACT FROM AUTHOR]

Indoor air quality is a determining factor in maintaining occupant comfort, especially in educational environments such as classrooms. Traditional methods of monitoring indoor air quality and occupancy, such as casual inspections or periodic measurements, do not provide timely and accurate information for those who must make decisions about ventilation and controlling the number of occupants. Internet of Things (IoT) technology has opened new possibilities for monitoring and controlling indoor air quality in real time. In this paper, an IoT-based system for monitoring indoor air quality and occupancy in a classroom is presented. The system consists of low-cost sensors that collect data on temperature, humidity, dust, carbon dioxide levels and occupancy, which is then transmitted to a cloud-based platform for analysis and visualization. Evaluation of the system in a real-world classroom environment has shown its effectiveness in detecting changes in air quality and the number of occupants. [ABSTRACT FROM AUTHOR]

Volatile organic compounds (VOCs) are pollutants that can reduce indoor air quality and the leading cause of respiratory disorders such as Acute Respiratory Infections (ARI) and Sick Building Syndrome (SBS). Because of that, the indoor air must be cleaned by degrading VOCs. One of the non-thermal plasma applications to degrade VOCs is negative ion plasma or Negative Air Ion (NAI), i.e., ionized air becomes negatively charged. Superoxide is one of the most widely produced NAI and can be a degrading agent for VOCs in the air. The ability of plasma negative ions in degrading VOCs was further investigated using case studies in 1500 ppm ethanol and 600 ppm toluene. The research was conducted by injecting ethanol and toluene gas into the prototype, equipped with a negative ion plasma generator that produces a DC voltage of 5.6 kV. The measured negative ion density in the prototype is 8 x 106 – 1.2 x 107 ion/m3. The Removal efficiency of ethanol reached 99.94% during a contact time of 4 hours with a final concentration of 0.97 ppm, while that of toluene reached 99.77% during a contact time of 5 hours with a final concentration of 1.33 ppm. Fan blowing speed can increase the performance of negative ion plasma, where the fan speed of 1600 RPM at a voltage of 12VDC gives the best results in this study. [ABSTRACT FROM AUTHOR]

Air-conditioning accounts for up to 60% of the energy use in buildings in Kuwait. Also, air-conditioning consumes about 70% of the electricity during peak hours. Widespread air-conditioning system installation increases the total energy consumption resulting in a large carbon footprint and raising the peak load demand, causing excessive strains on the power grid. Heat-driven air-conditioning systems that use solar energy are now emerging as alternatives to electricity-driven convectional refrigerated air conditioners. These systems are more energy-efficient, with lower carbon emissions while also ensuring better indoor air quality and comfort when optimally designed. Among the heat-driven air- conditioning systems, the desiccant cooling system and vapor absorption refrigeration system are among the most potential systems. This paper presents a numerical investigation on the design optimization of various solar desiccant cooling systems for Kuwait's climate. The numerical model of the system is developed using validated components. Various design configurations analyzed include solar heating system, regeneration air for the desiccant wheel. It is found that an evacuated tube solar collector in conjunction with returning air from the building to regenerate the desiccant wheel provides the best results. [ABSTRACT FROM AUTHOR]

The basement parking building in office building X is a closed space where the parking area has an inadequate ventilation system, so the air in the room feels hot. To provide a comfortable room, an analysis of the ventilation system was carried out. This ventilation system analysis is carried out to find out what causes the hot air in the room. To analyze indoor air quality, total vehicle emissions in the parking lot are calculated using air pollutant parameters, namely CO and NO2. In addition to calculating the ventilation flow rate, it measures air velocity and temperature. The results of the research conducted are that the air pollutant parameters CO and NO2 are still within the safe threshold and the vehicle emission threshold standard for health is still below 29 mg/m3 for CO and 25 mg/m3 for NO2. The solution to overcome the problem in the parking lot is to install a booster fan so that the air in the room can flow better, and the air condition is not hot. After the application of the booster fan, the average air velocity increased from 0.69 m/s to 2.88 m/s and the average temperature decreased from 34.4°C to 31.5°C. [ABSTRACT FROM AUTHOR]

The paper deals with the problem of the occurrence of volatile organic compounds in the work environment, specifically in administrative public buildings in the context of the quality of the indoor environment (IAQ). The importance of indoor air quality has become an interest in research and development in the last 10 years, mainly due to the increasing quality of the airtight envelope of the building and the prevailing trend of forced ventilation. Indoor air quality is directly related to Sick Building Syndrome (SBS). The occurrence of VOC emissions within 10 selected office buildings in the South Bohemian Region in the Czech Republic is demonstrated in the practical case study. Detection of volatile organic compounds was performed using ultra-fast electronic zNose Model 4200 Analyzer based on gas chromatography with patented SAQ detector. The results of the case study demonstrate how important a quality element and the necessary implementation of the building and the design of the indoor working environment is. [ABSTRACT FROM AUTHOR]

Airborne virus is a major concern in this pandemic era. Viruses can spread indoors even though health protocols have been implemented so the air quality in indoor environment need to be controlled. Air quality can be measured through several aspects, such as temperature, humidity, and CO2 levels. Each aspect can be analyzed for its concentration according to the predetermined threshold value of Air Quality Standard. This study offers an IoT-based smart indoor air sterilization system that can be used to monitor air quality by adding a HEPA filter, UV lamp, and carbon in air purifier. The proposed system can be monitored through the android application in real time. The test results show that the proposed system can run according to the specified parameter values given. For UV lamp is turn on, temperature produces an average temperature of 24C, CO2 level is around 314ppm, and humidity level is 45 – 65%. For further analysis, the air purifier need to be placed in different location to determine the coverage of air purifier and to examine the size of product that suit the need. [ABSTRACT FROM AUTHOR]

The window is one of the most important aspects of a building. It aims to obtain good lighting and meet the requirements for Indoor Air Quality. A restroom is a place where most surfaces are wet, and it causes the relative humidity to become high. As a result, lighting must be considered in this space. The men's toilet on the second floor of the Bina Nusantara University campus in Malang is the subject of this research. Interviews with building operators, cleaners and firsthand surveys of the location were also undertaken. The author used the results of interviews to help specify the ventilation system. The author utilizes a lux meter to measure the lighting layout. According to the findings, this toilet uses mechanical ventilation in the form of an exhaust fan. On the other hand, this area employs downlights that meet lighting standards in terms of brightness and color temperature selection in the artificial lighting system. In the current situation, there is a shortage of energy efficiency. As a result, this study offers a method for preserving electrical energy. This study uses an Arduino Mega and several sensors to help automate the operation of these electrical devices. [ABSTRACT FROM AUTHOR]

This paper presents the results of a research questionnaire of building occupants in selected commercial and office buildings in Hyderabad. A total of 614 building occupants participated in the study from selected 28 commercial and office buildings. Many researchers have used questionnaire as an effective tool to measure the comfort of building occupants. Hence, teams were formed for conducting the questionnaire survey in different buildings. The occupants were explained the purpose of the study and asked to give their feedback on the form. The data was collected and analyzed to know their level of satisfaction with the building environment. Results show that the participants were mainly young males who spend a considerable time indoors. HVAC system is operational for most part of the year in those buildings. Some occupants have reported health issues like nasal irritation, headache, throat irritation, dry mouth, and drowsiness. These symptoms were related to their health history or seasonal effects besides airconditioning issues. A majority of occupants have expressed their satisfaction with the building environments and all its environmental parameters. However, a small percentage of respondents have expressed dissatisfaction also which could be related to their individual backgrounds, medical issues, workloads, and attitudes. However, cigarette smoking remains an issue in commercial buildings. [ABSTRACT FROM AUTHOR]

Attention to the importance of indoor air quality (IAQ) has increased in recent years. It is a topic that has grabbed the interest of scholars, researchers, and the public. Unfortunately, research shows that many indoor locations such as houses, nurseries, schools and offices have been suffering from unhealthy indoor air. Current literature shows that the most significant indoor air contaminants are CO2, CO, NO2, O3, TVOCs, and particular matter along with thermal conditions such as temperature and humidity. The presence of those contaminants affects human health negatively. While different methods to improve indoor air do exist today, yet there is no one best solution. Green Lean Six Sigma (GLSS) frameworks has been used successfully to tackle the problems related to environmental issues in different fields. Accordingly, this paper tries to address a core question of the possibility of applying GLSS approach to improve indoor air quality within various facilities. The definition of GLSS and an overview of the developed GLSS frameworks and their applications will be presented through a review of the relevant articles available in the literature. The findings will highlight possible challenges and featured strong promising research opportunities regarding the use of GLSS approach to improve indoor air quality. The major finding is that there is a lack of implementation of GLSS in different fields and exploring new fields will most probably show positive feedback. [ABSTRACT FROM AUTHOR]

Air is very important for every life in the world, but over the last two decades air pollution has increased tremendously due to the growth of industries and population. Therefore, every life in the world can be infected with short- and long-term diseases by inhaling polluted gas, which can sometimes lead to immediate death. As people spend more time in indoor areas, indoor polluted air can also cause more harm to life. This system was proposed and developed to solve the problem on indoor air quality. This system finds the complete solution by monitoring the indoor air quality, after which it produces good purified air in our surroundings. Using Internet of Things (IoT) sensors, the system measures real-time air pollutants such as carbon dioxide, carbon monoxide, volatile organic matter, temperature and humidity. Since monitoring is not the solution to the problem we need to have a definite solution called air purification. Here it consists of two stages, in the first stage the air has to go through conventional air filters and in the second stage the same air passes through the UV light chambers for sterilization, after which it produces fresh air into the atmosphere. The ESP32 microcontroller is used to develop the system. It updates the observed data to the web server where the end user data can be read and analyzed. During the launch process, we observed that air quality improved by 99% and that it was effective against germs, bacteria and viruses. [ABSTRACT FROM AUTHOR]

The main role of ventilation systems and especially air conditioning systems is to create indoor conditions and air quality inside the rooms that are independent of external atmospheric influences. The sizing of ventilation systems and especially of air conditioning systems is done, in most cases, by considering the climatic elements as a basis for calculation. The real limit to air quality insurance it consists in maintaining in the air certain concentrations of harmful substances which do not endanger human health and do not create discomfort. The air condition parameters of interest for the ventilation and air conditioning technique are air temperature and humidity, atmospheric pressure and air velocity. For this study, in the experimental laboratory, the test was performed on the variation of the air condition parameters in the conditions of conveying a quantity of methane gas through the ventilation duct. During the experiment, the operating parameters of the drive motor were changed using a frequency converter on levels 50; 40; 30; 20; 10 and 5 Hz. The ventilation system used was structured by means of flow converters which were fixed in the open position. The ventilation system as well as the flow variators were operated by the SCADA type command and control system. The paper will present the analysis of the variation of the state parameters (temperature, humidity, absolute pressure and air velocity) by introducing a constant amount of methane gas in the ventilation duct. [ABSTRACT FROM AUTHOR]

People are aware that outdoor air pollution is harmful to their health, but indoor air pollution can also cause serious health complications. This study aims to determine the indoor air quality of modernized jeepneys to identify the best solutions to eliminate harmful emissions and provide comfort and good health for the occupants. The researchers conducted an IAQ assessment, including the following concentrations: carbon dioxide, carbon monoxide, PM10, PM2.5, formaldehyde, temperature, and relative humidity. In addition, a correlation of the parameters with the number of passengers and the cycle of opening-closing of the door were identified. A survey was conducted to explain the sampling results further. Based on the results, PM2.5 and PM10 were the only contaminants that appeared to be within the standards. Temperature and carbon dioxide both have a relationship with the number of passengers. Carbon dioxide and PM2.5 both have a relationship with the cycle of opening-closing of the door. The rest of the results and recommendations drawn based on these results are discussed in the latter part of this paper. [ABSTRACT FROM AUTHOR]

Grocery stores are primary establishments where people purchase food, supplies, and household items. Most stores are open daily, and some even for 24 hours. Customers enter Rodamel Grocery Store in Tuguegarao City, Cagayan, during the operating hours to buy goods. To ensure public health safety, there is a need to measure/analyze the IAQ of the Rodamel Grocery Store and compare the gathered data to existing IAQ standards. For three consecutive days, air quality monitoring devices were used to measure the ventilation, temperature, humidity, also the concentrations of CO2, formaldehyde, and particulate matter such as PM2.5 and PM10. Bioaerosol samples were also collected and grown using a process called Growth Culture Analysis to qualitatively identify how much is inhaled depending on the grocery shopper’s exposure time. Based on the results, only the temperature and the humidity did not meet the acceptable ranges from the standards, exceeding the maximum of 27 ̊C and 60 respectively. For the bioaerosol sampling, all the 18 samples show a relationship that the longer the shopper stays inside the grocery store, the more bioaerosol exposure is experienced. Further recommendations are also given to the Rodamel Grocery Store to address their indoor air issues. [ABSTRACT FROM AUTHOR]

The Internet of Things (IoT) provides a platform that allows devices to connect, discover and remotely control through the internet. This work aims to develop an Internet of Things-based system for an oil company's laboratory. It is intended to monitor its environmental conditions and parameters through air quality sensors, thus providing intelligent monitoring and greater certainty of working conditions. The system development utilizes ESP8266, Arduino UNO processor, solid-state relay, and sensors. The proposed work monitors the air quality, humidity, and temperature of the laboratory environment. It included an active air exhaust control system. A database has been created with the purpose of data analysis and access to status history. As a result of this system implementation, it is expected to improve laboratory management and occupational health and hygiene. [ABSTRACT FROM AUTHOR]

In this review, the impact of quality of the indoor air on the human health were analyzed. The most important outcomes recap the anxieties of indoor air contamination (IAC) and afford an unfathomable consideration of in what way the impurities contribute to, also act together to emphasize the unfavorable things on the human health. Disputes which have developed and amplified in significance are indoor chemistry, floating air contagion, and the sway on performance. Common developments of intensifying comfortable circumstances of the medium class, amplified inhabitants' density in capitals, primer of innovative artificial resources and dependence on childcare conveniences consume led to better concentration of disclosure to indoor air contamination (IAC). Reactions to weather variation, energy preservation and particular policies to accomplish the multifaceted task of IAC have not been active in improving the weakening of interior air superiority. Modernizations in air circulation, airborne cleaning, modularization of interior ecological devices/systems, and leveraging on insolent techniques and recognizing systems which include procedures that elevates interior air superiority with predictable performance pointers are significant improvements in the direction of an all-inclusive solution. User commitment, both as a device and display of favorites, at what time incorporated through such inventions, might user in the subsequent imperative example in the direction of attaining tolerable indoor ecological superiority away from the present descriptions of satisfactoriness from inhabitants-centered conditions to one that embraces the distinct on an as- desirable, when-required and as-favored basis. [ABSTRACT FROM AUTHOR]

Interior airborne superiority and its consequence on inhabitant comfort and wellbeing is an imperative part of this review. This review article provides an ultra-modern learning over a wide-ranging analysis of the collected works, through founding relations among Interior airborne superiorities and inhabitant comfort and wellbeing. A variety of concerns for example sick construction syndrome, interior airborne superiority, warm air luxury, chromatic luxury and auditory luxury are reflected in this article. The difficulty of the connection among inhabitant luxury and comfort constraints with interior airborne superiority are additional intensified owing to connections that these bounds have by all other as fine. Recognized on the analysis of collected works in these ranges it is well-known that an interior airborne superiority desires to contemplate inhabitant comfort factors exact at the commencement. The information recognized as fragment of this article will be supportive for investigators. This review article will moreover be of boundless advantage to investigators who attempt to commence investigation in interior airborne superiority on human health and comfort and might performance as a worthy preparatory idea for them. [ABSTRACT FROM AUTHOR]

Urbanization, increase in population and change in lifestyle of human beings increased pressure on natural resources and accumulation of industrial waste in the environment. Dumping and landfilling of such industrial waste especially the solid waste is leading towards severe environmental degradation in the form of water pollution, air pollution and soil pollution etc. Due to increase in installation of more paper mills, there is rapid increase in quantity of solid waste from these industries. In recent years, utilization of lime mud generated from paper mill has been emerged as a potential method to reuse/recover the usable rich material and reduce the quantity of waste and its disposal cost for landfilling/dumping. In this experimental examination, an effort has been complete to examine the behavior of the bricks developed using the waste (lime mud) from paper industry waste and other paper sludge by partial replacing the clay to the extent from 10% to 50%. The bricks were developed by using varying composition. Later execution various tests, it has been detected that bricks made from partial replacement of clay with lime mud are light weight, having desirable compressive strength, corrosion resistant. The indoor air quality assessment of buildings made of these bricks indicted little to no impact on ambient air quality. [ABSTRACT FROM AUTHOR]

This study discusses the characteristics of the physical environment in the classroom at Malaysian public universities. The study of the physical environment is essential because the mastery of Arabic learners is crucial. Research is usually done only on aspects of teaching and learning. While aspects of the environment are rarely found, therefore, this study will describe the characteristics of the physical environment conducive to teaching and learning in the classroom at Malaysian public universities. A total of 494 students from eight Malaysian public universities responded to the questionnaire distributed. This study uses descriptive quantitative research methods. The instruments are composed of four structures, namely furniture and equipment, lighting, technology and air quality indoors. The researcher uses the Statistical Package for Social Science (SPSS-22) software for factor analysis (EFA), and factor validation analysis (CFA). The result found that the nature of the physical learning environment in the Arabic classroom has been interpreted from the analysis of the perceptual score obtained. Although students at public universities in Malaysia regard the Arabic language learning atmosphere in this classroom favourably, they wish to enhance the real learning experience in the classroom in all four constructs. [ABSTRACT FROM AUTHOR]

Managing indoor air quality in elementary schools is very important since children are more vulnerable than adults and unique characteristics of schools such as higher level of occupancy than other buildings, containing a variety of pollutant sources, poorly designed ventilation systems, etc. EPA found that more than 70,000 classrooms in the US that in use today have short-term radon levels above 4 pCi/L. Thus, this study aimed to describe radon levels in elementary schools and its associated factors. This is a systematic literature review which collects and evaluates published papers regarding radon concentration assessments in classrooms from various countries between 2010-2020. A Center for Reviews and Dissemination (CRD) research protocol was used. 23 literatures were selected. It shows that radon activity ranged from 26.65 - 480 Bq/m3, median: 119 Bq/m3, arithmetic mean: 133.43 ± 95.14Bq/m3, geometric mean: 109.06 ± 1.87 Bq/m3. Numerous factors are associated with indoor radon levels, which can be classified into building, building location; and meteorological factors. [ABSTRACT FROM AUTHOR]

In response to the pandemic caused by the COVID-19 virus, many countries adopted control and mitigation measures (e.g., lockdown, social distancing, intermittent attendance, etc.) that significantly increase the amount of time people spend inside the built environment. Nevertheless, the need to resume activities in attendance and ensure the continuity of businesses that cannot be stopped has led to the adoption of measures to reduce the risk of contagion, mainly involving increased ventilation of indoor environments. In this context, the management of Indoor Air Quality became crucial to ensure occupants' health while optimizing thermal comfort and buildings' energy demands. In the scientific literature, one of the most explored solutions to this optimisation problem is the adoption of a digital twin (DT) triggered by the broader diffusion of sensors and technological systems. DTs have three main domains: the physical one (the asset), the virtual one (the digital counterpart), and the cyber-physical (sensors and devices to send data to the digital domain) that binds the two together. However, installing a proper number of sensors in existing buildings may be too expensive or impossible due to technical problems. This study introduces a methodology to take advantage of DTs in existing buildings where technical and economic reasons hinder the deployment of a fully developed cyber-physical domain, replacing hard sensors with soft/virtual ones deploying Artificial Intelligence (AI) techniques. AI can leverage the cyber-physical part of DTs by retrieving useful information on occupant behavior from even few available data, thus allowing for a fully functional DT even in existing buildings with a limited number of installed sensors. The methodology has been tested on a school building in Italy, where a DT has been deployed. In the case study, low-cost and easy-to-install sensors are used to monitor CO2 levels within various rooms. Many control and mitigating protocols adopted during the pandemic set thresholds and limits for CO2 concentrations, requiring increased ventilation once a certain CO2 threshold is reached, with consequent repercussions on indoor comfort and energy consumption. In this study, the opening of windows is automatically detected with AI techniques by examining CO2 temporal trends, thus automatically recognizing building users' behaviors. Consequently, systems can be properly managed to limit energy consumption and thermal discomfort (e.g., turning off the heating while the window is on). Therefore, the introduced methodology enables a DT approach, overtaking difficulties often encountered in installing sensors in existing assets, with obvious benefits in terms of health, energy consumption, and economic savings. [ABSTRACT FROM AUTHOR]

One of the tasks defined in the basic principles of sustainable building construction is to ensure a quality indoor environment and the health and wellbeing of the building’s users. Especially in the current epidemiological period, people spend more than 90% of their time indoors. In almost every indoor environment (IE), there is a certain number of ornamental houseplants. In most cases, these are ornamental plants with leaves or flowers. These plants give us aesthetic impressions and improve the well-being of building users. Integration of these vegetation elements into building interiors can lead to a decrease in the incidence of Sick Building Syndrome (SBS) and Building-Related Illness (BRI). Plants can improve indoor air quality (IAQ). Although plants are a source of moisture, take up Carbon Dioxide (CO2) and release O2 through light-dependent photosynthesis, and effective filters to remove pollutants (volatile organic compounds) and improve indoor air quality, specific types of indoor plants are very often selected only by visual and aesthetic perception. [ABSTRACT FROM AUTHOR]

Sustainability is a criterion defined since the 1980s, essential in all areas of activity, without which development cannot be acheived. Thermal insulation mattresses produced using sheep wool, successfully meet the conditions imposed by this criterion. This type of building material ensures the responsible use of non-renewable natural resources, the possibility of reuse and recycling of materials, contributes to environmental protection and pollution reduction, energy saving and provides a hygienic and healthy living climate. This paper analyzes how sheep wool mattresses meet sustainability requirements, simultaneously with compliance with specific requirements in construction based on the criteria of regulation (EU) no. 305/2011 of the European Parliament and of the Council of 9 March 2011 laying down harmonised conditions for the marketing of construction products. At the same time, the physical and mechanical performances of 20 types of sheep wool mattresses, from 7 manufacturers, available on the international market, are presented. This identifies the strengths of these products (thermal insulation performance, low overload of the structural strength of buildings due to low density, low environmental impact and contribution to improving indoor air quality), as well as weaknesses (high water absorption, low mechanical strength, which make it difficult to use outside buildings, requiring either indoor location, additional protection measures for outdoor location). However, cumulating all these aspects, it can be said that sheep wool mattresses are a good heat-insulating material, which successfully meets the requirements of sustainable development, the benefits in terms of environmental impact and quality of life recommending them as a possible substitute for some sintering heat-insulating materials, highly polluting and hardly or not at all biodegradable. [ABSTRACT FROM AUTHOR]

This study assessed the physical and chemical parameters related to indoor air quality (IAQ) at Universiti Tenaga Nasional (UNITEN) and the IAQ of selected campus buildings were compared with guidelines provided by DOSH. This study is especially important as students spend most of their time indoors thus making them more vulnerable to exposure to indoor contaminants. Seven sampling locations around the UNITEN campus were selected which all have different layout. The method of data collection is based on Industry Code of Practice on Indoor Air Quality 2010 (ICOP). The indoor contaminants were recorded using real-time monitoring method and the parameters of interest are the Particulate Matter (PM2.5 and PM10), Total Volatile Organic Compound (TVOC), relative humidity and temperature. Results show that the parameters of IAQ level in UNITEN is at a safe level as it is well below the DOSH permissible limit. One-way ANOVA analysis was used to identify whether or not the mean of the IAQ parameters specifically PM2.5, PM10 and TVOC are the same and belongs to the same population. Statistical analysis also shows that there was no significant difference in IAQ level between all sampling locations (P≤0.05). [ABSTRACT FROM AUTHOR]

An air conditioning unit is a machine that is designed to provide comfort cooling to its users. One of these types is the window-type air conditioning unit (ACU) which is most common in the Philippine market. The portable-type ACU is another type but it's not as popular as the other. Since data on the portable-type ACU is scarce, the window-type ACU is the more suggested type used. The study aims to compare the Energy Efficiency Ratio (EER), temperature uniformity, and the Indoor Environmental Quality (IEQ) such as carbon dioxide concentration and noise levels of these two types of air conditioning units. In the Energy Efficiency Ratio and temperature uniformity test results, the window-type ACU yielded a better EER and has a more uniform cooling than the portable-type ACU. In the CO2 concentration tests, the CO2 concentration of the room using the portable-type ACU was lower than when using the window-type ACU. From the tests conducted, the CO2 concentrations were a factor of the air changes per hour of both ACUs and the breathing activity of the occupants as well. Lastly, the noise level results for both ACUs showed that neither was within the standards for the maximum noise level produced in a room. [ABSTRACT FROM AUTHOR]