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Knowledge of indoor air quality (IAQ) in cob buildings during the first few months following their delivery is of vital importance in preventing occupants' health problems. The present research focuses on evaluating IAQ in cob buildings through a prototype built in Normandy, France. To achieve this, the prototype was equipped with a set of sensors to monitor various parameters that determine indoor and outdoor air quality. These parameters include relative humidity (RH), carbon dioxide (CO2), nitrogen dioxide (NO2), ozone (O3), particulate matter (PM1 and PM10), and volatile organic compounds (VOCs). The obtained experimental results indicate that, overall, there is good indoor air quality in the prototype building. However, there are some noteworthy findings, including high indoor RH and occasional spikes in CO2, PM1, PM10, and VOCs concentrations. The high RH is believed to be a result of the ongoing drying process of the cob walls, while the peaks in pollutants are likely to be attributed to human presence and the earthen floor deterioration. To ensure consistent good air quality, this study recommends the use of a properly sized Controlled Mechanical Ventilation system. Additionally, this study explored IAQ in the cob building from a numerical perspective. A Long Short-Term Memory (LSTM) model was developed and trained to predict pollutant concentrations inside the building. A validation test was conducted on the CO2 concentration data collected on-site, and the results indicated that the LSTM model has accurately predicted the evolution of CO2 concentration within the prototype building over an extended period. [ABSTRACT FROM AUTHOR]

People spend most of their time in indoor environments without knowing about the air quality in these spaces. In this study, indoor low-cost sensors were used (for 5 months) to assess the comfort and air quality patterns in two indoor households. To strengthen the robustness of the considered approach and build confidence in the obtained comfort and indoor air quality (IAQ) levels, the sensor measurements were also compared against information from reference monitoring equipment; in which, high correlation coefficients were obtained (> 0.85) and also low errors (on average 22%). The IAQ results were strongly influenced by the residents' activity and behaviour, the outdoor weather conditions, and indoor/outdoor air pollution sources. Overall, the recommended values of temperature and relative humidity for the occupant's comfort in indoor environments were not fulfilled. The highest particulate matter (PM) levels were recorded at the weekend (on average +14% higher), while maximum CO2 and CO levels were obtained on the weekdays (on average +9% higher). PM daily profiles followed the outdoor concentrations with the maximum levels at the end of the night and the lowest values in the early morning/mid-afternoon. The highest and lowest CO2 concentrations were registered in the early morning (< 1536 ppm) and mid-afternoon (< 627 ppm), respectively, while the CO daily profiles showed a high impact of outdoor emissions, with the minimum concentrations up to 0.81 mg m−3 (at 10 a.m. or 6 p.m.), and a maximum concentration of 1.87 mg m−3 (at 10 p.m.). Real-time comfort conditions and IAQ levels are a powerful approach to providing fast decisions to minimise human exposure and prevent negative health impacts. [ABSTRACT FROM AUTHOR]

Previous studies have shown that poorly ventilated classrooms can have negative impact on the health of children and school staff. In most cases, schools in Serbia are ventilated naturally. Considering their high occupancy, classroom air quality test determines the level of air pollution, after which it is possible to implement corrective measures. The research presented in this study, was conducted in four schools which are located in different areas and have different architecture designs. Measurements in these schools have been performed during the winter (heating season) and spring (non-heating season) and the following results were presented: indoor air temperature, relative humidity, and carbon dioxide concentration. These results show that the classroom average concentration of carbon dioxide often exceeds the value of 1500 ppm, during its full occupancy, which indicates inadequate ventilation. Measurement campaigns show that carbon dioxide concentration increased significantly from non-heating to heating season in three of the four schools. Analysis of measurements also determined high correlation between relative humidity and carbon dioxide concentration in all schools in winter season. This fact may constitute a solid basis for the fresh air supply strategy. [ABSTRACT FROM AUTHOR]

Considering that air conditioning is widely applied for improving human standard of living, this present investigation is focused on the optimization of indoor air quality characteristics of air-conditioned cars using the Gray relational analysis (GRA) and the response surface methodology (RSM). The air-conditioned space is selected and the experiments are planned as per experimental design to study the effects of human load, fresh air supply, and air velocity on human comfort conditions. Mathematical models are developed to predict the comfort conditions, namely temperature, CO level, and relative humidity over a specified range of input conditions. The optimum values of comfort conditions for varying input conditions are found by assigning weightages to individual responses using GRA and RSM. [ABSTRACT FROM AUTHOR]

The present investigation was focused on the analysis of indoor air quality characteristics of an air conditioned car using statistical approach. The conditioned space was selected and the experiments were planned as per design of experiments to study the effect of human load, fresh air supply and air velocity on the human comfort conditions. The nonlinear regression models were developed to predict the comfort conditions namely temperature, CO2 level and relative humidity over a specified range of input conditions in this investigation. [ABSTRACT FROM AUTHOR]

Studies of the indoor air quality of restaurants have rarely focused on ventilation system performance in relation to air pollutants and climatic factors. This study was conducted in eight restaurants to examine this issue by determining the ventilation flow rates and the levels of carbon dioxide (CO[sub 2]), ambient temperature, and relative humidity during at least one complete shift of serving a meal. The mean values of number of dining patrons, ventilation flow rates, and the levels of CO[sub 2], ambient temperature, and relative humidity were not significantly different in the nonsmoking dining rooms and the smoking dining rooms. The mean ventilation flow rates in individual restaurants ranged from 42-113 cubic feet per minute per person (cfm/person), overall exceeding the recommended lower limit of 30 cfm/person. The mean levels of CO[sub 2] in two restaurants (646 and 819 ppm) were below, and in the other six restaurants (ranging 1012-1820 ppm) were above the recommended upper limit of 1000 ppm. The levels of CO[sub 2] in each restaurant significantly correlated with the number of dining patrons and in four restaurants accumulated gradually over time. In the nonsmoking dining rooms, the levels of CO[sub 2] increased significantly as the ventilation flow rates decreased. The mean ambient temperature in restaurants (ranging from 22°C-24°C) were within the recommended range of 20°C-26°C. The mean relative humidity in six restaurants (ranging from 46%-59%) were within the recommended upper limit of 60 percent, and in two restaurants (62% and 71%) were slightly higher than this recommended limit. It was concluded that although the mean ventilation flow rates in all restaurants exceeded the recommended value, the design of the ventilation system or the distribution of air flow rate in some sections of restaurants were not appropriate to keep the levels of CO[sub 2] and relative humidity at some measurement locations below the recommended limits. [ABSTRACT FROM AUTHOR]