This study aims to optimize the influence of the inlet inclination angle on the Indoor Air Quality(IAQ),heat,and temperature distribution in mixed convection within a two-dimensional square cavityfilled with an air-CO_(...This study aims to optimize the influence of the inlet inclination angle on the Indoor Air Quality(IAQ),heat,and temperature distribution in mixed convection within a two-dimensional square cavityfilled with an air-CO_(2)mixture.The air-CO_(2)mixture enters the cavity through two inlet openings positioned at the top wall,which is set at the ambient temperature(TC).Three values of the Reynolds numbers,ranging from 1000 to 2000,are considered,while the Prandtl number is kept constant(Pr=0.71).The temperature distribution and streamlines are shown for Rayleigh number(Ra)equal to 104,three inlet inclination anglesϕ(0,π/6 andπ/4)and three CO_(2)concentrations values(1500,2500,3500 ppm)applied at both hot vertical walls(maintained at a constant temperature TH).Afinite volume method is used under the assumption of two-dimensional laminarflow to solve the NavierStokes and energy equations.The results indicate that inlet inclination angle has an impact on the indoor air quality(IAQ),which,in turn,affects the heat transfer distribution and thermal comfort within the cavity.展开更多
The amount of moisture in the air is represented by relative humidity(RH);an ideal level of humidity in the interior environment is between 40%and 60%at temperatures between 18°and 20°Celsius.When the RH fal...The amount of moisture in the air is represented by relative humidity(RH);an ideal level of humidity in the interior environment is between 40%and 60%at temperatures between 18°and 20°Celsius.When the RH falls below this level,the environment becomes dry,which can cause skin dryness,irritation,and discomfort at low temperatures.When the humidity level rises above 60%,a wet atmosphere develops,which encourages the growth of mold and mites.Asthma and allergy symptoms may occur as a result.Human health is harmed by excessive humidity or a lack thereof.Dehumidifiers can be used to provide an optimal level of humidity and a stable and pleasant atmosphere;certain models disinfect and purify the water,reducing the spread of bacteria.The design and implementation of a client-server indoor and outdoor air quality monitoring application are presented in this paper.The Netatmo station was used to acquire the data needed in the application.The client is an Android application that allows the user to monitor air quality over a period of their choosing.For a good monitoring process,the Netatmo modules were used to collect data from both environments(indoor:temperature(T),RH,carbon dioxide(CO_(2)),atmospheric pressure(Pa),noise and outdoor:T and RH).The data is stored in a database,using MySQL.The Android application allows the user to view the evolution of the measured parameters in the form of graphs.Also,the paper presents a prediction model of RH using Azure Machine Learning Studio(Azure ML Studio).The model is evaluated using metrics:Mean Absolute Error(MAE),Root Mean Squared Error(RMSE),Relative Absolute Error(RAE),Relative Squared Error(RSE)and Coefficient of Determination(CoD).展开更多
Besides the need for low-cost instruments for air pollution measurement and detection,nowadays there are many concerns about air pollution due to the fast changes and used technologies.This research was applied using ...Besides the need for low-cost instruments for air pollution measurement and detection,nowadays there are many concerns about air pollution due to the fast changes and used technologies.This research was applied using an MQ2 gas detector,and microcontroller/Arduino-Uno.The design steps included bonding and connecting readymade sensors,coding,and finally testing the device.Testing has been conducted in Environment and Pollution Engineering Department laboratories,at the Technical Engineering College of Kirkuk.This study proposed the use of an MQ2 sensor for multi-gas rate detection which can exist indoors.The system uses also a DHT22 sensor for measuring environment temperature and humidity.The sensors are connected to Arduino and LCD to present data on LCD by powering the system with external power.Overall,the testing was conducted,and the device served as a measuring tool for indoor air as an accurate multi-gas rate detector.展开更多
Individuals spend 90% of their time indoors, primarily at home or at work. Indoor environmental factors have a significant impact on human well-being. It was a longitudinal study that assessed the major factors that r...Individuals spend 90% of their time indoors, primarily at home or at work. Indoor environmental factors have a significant impact on human well-being. It was a longitudinal study that assessed the major factors that reduce indoor air quality, namely particulate matter, and bio-aerosols, using low-cost sensors and the settle plate method, respectively also to determine the effect of atmospheric parameters and land use patterns in households of commercial, industrial, residential, slum, and rural areas of the city. PM2.5 concentration levels were similar in most parts of the day across all sites. PM10.0 concentration levels increased indoors in a commercial area. PM2.5 concentration showed a negative correlation with temperature and a positive correlation with relative humidity in some areas. Very high values of PM2.5 concentration and PM10.0 concentration have been observed in this study, inside households of selected rural and urban areas. Pathogenic gram-positive cocci, gram-positive rods, Aspergillus, and Mucor species were the most common bacterial and fungal species respectively found inside households. This study examined particulate matter concentration along with bio-aerosols, as very less studies have been conducted in Jaipur the capital of Rajasthan, a state in the western part of India which assessed both of these factors together to determine the indoor air quality. Rural households surrounding the periphery of the city were found to have similar pollution levels as urban households. So, this study may form the basis for reducing pollution inside households and also for taking suitable measures for the reduction of pollution in the indoor environment.展开更多
To study the indoor air qualities（IAQ）of large commercial office buildings in Hunan province of China and the corresponding improvement methods,the IAQ of a large commercial office building in Changsha in July,2008,...To study the indoor air qualities（IAQ）of large commercial office buildings in Hunan province of China and the corresponding improvement methods,the IAQ of a large commercial office building in Changsha in July,2008,is investigated.A questionnaire survey and field tests are used to collect data.According to the data of twelve rooms in this building,objective evaluation and the subjective evaluation of the IAQ are obtained.Almost all of the environmental parameters in these rooms basically meet the standards of the objective evaluation.But the average concentration of carbon dioxide in most rooms cannot reach the value of the cleanliness standards,1 255 mg/m^3.The average acceptability of the IAQ in these rooms is 71%,which is lower than the value of the ASHRAE 55—1992 standards,80%.The proper increase in the wind speed and the indoor fresh air supply can greatly improve the objective evaluation and the subjective evaluation of the IAQ.展开更多
A methodology for identifying volatile organic compounds （VOCs） and determining air quality of indoor air has been developed. The air samples are collected using pump samplers by the inhabitants when they perceive o...A methodology for identifying volatile organic compounds （VOCs） and determining air quality of indoor air has been developed. The air samples are collected using pump samplers by the inhabitants when they perceive odorous and/or discomfort episodes. Glass multi-sorbent tubes are connected to the pump samplers for the retention of VOC. The analysis is performed by automatic thermal desorption （ATD） coupled with gas chromatography-mass spectrometry （GC/MS）. This methodology can be applied in cases of sick building syndrome （SBS） evaluation, in which building occupants experience a series of varied symptoms that appear to be linked to time spent in the building. Chemical pollutants concentrations （e.g., VOC） have been described to contribute to SBS. To exemplify the methodology, a qualitative determination and an evaluation of existing VOC were performed in a dwelling where the occupants experienced the SBS symptoms. Higher total VOC （TVOC） levels were detected during episodes in indoor air （1.33 ±1.53 mg/m^3） compared to outdoor air （0.71± 0.46 mg/m^3）. The concentrations of individual VOCs, such as ethanol, acetone, isopropanol, 1-butanol, acetic acid, acetonitrile and 1-methoxy-2-propanol, were also higher than the expected for a standard dwelling. The external source of VOC was found to be an undeclared activity of storage and manipulation of solvents located at the bottom of a contiguous building.展开更多
Objective The changes in serum adipokines and cytokines related to oxidative stress were examined during 3 months ‘Off to On’ and ‘On to Off’ periods using negatively charged particle-dominant indoor air condition...Objective The changes in serum adipokines and cytokines related to oxidative stress were examined during 3 months ‘Off to On’ and ‘On to Off’ periods using negatively charged particle-dominant indoor air conditions（NCPDIAC）.Methods Seven volunteers participated in the study,which included ‘OFF to 3 months ON’ periods（ON trials） for a total of 16 times,and ‘ON to 3 months OFF’（OFF trials） periods for a total of 13 times.Results With the exception of one case,serum amyloid A（SAA） levels decreased significantly during the ON trials.Conclusion Considering that SAA is an acute phase reactive protein such as C reactive protein（CRP）,this observed decrease might indicate the prevention of cardiovascular and atherosclerotic changes,since an increase in high-sensitive CRP is associated with the subsequent detection of these events.展开更多
This is the first detailed characterization of the airborne bacterial profiles in indoor environments. Two restaurants were selected for this study. Fifteen genera of bacteria were isolated from each restaurant and id...This is the first detailed characterization of the airborne bacterial profiles in indoor environments. Two restaurants were selected for this study. Fifteen genera of bacteria were isolated from each restaurant and identified by three different bacterial identification systems including MIDI, Biolog and Riboprinter. The dominant bacteria of both restaurants were Gram-positive bacteria in which Micrococcus and Bacillus species were the most abundant. Most bacteria identified were representative species of skin and respiratory tract of human, and soil. Although the bacterial levels in these two restaurants were below the limit of the Hong Kong Indoor Air Quality Objective （HKIAQO） Level 1 standard （i.e., 〈 500 cfu/m^3）, the majority of these bacteria were opportunistic pathogens. These results suggested that the identity of airborne bacteria should also be included in the IAQ to ensure there is a safety guideline for the public.展开更多
Experiments on the behavior of airborne microparticle sediments and their adhesion on glass slides were conducted in a laboratory located on the first floor of a teaching building. Clean tiles and glass slides were pl...Experiments on the behavior of airborne microparticle sediments and their adhesion on glass slides were conducted in a laboratory located on the first floor of a teaching building. Clean tiles and glass slides were placed at different angles （0°, 45° and 90°） with respect to the horizontal plane in the laboratory. The sedimentation of microparticles was investigated at certain time intervals （1 d, 3 d, l0 d and 30 d）. The results of testing, at day 30, show that the diameters of particles on the horizontal tiles varied from 20 to 80 μm; few particles with diameter less than 0.5 μm or greater than 100 μm were found. The amount of particle sediment on all the slides increased along over time, while the average diameter of particles was not correlated with time, nor with the angle of placement. The maximum particle size, the total particle surface area, the total perimeter of all particles and the cover ratio of light （the proportion of total area of particles to the observed area of the slides surfaces） did not change significantly within the first 10 days. Inspection of all the samples for the last 20 days, however, showed that these variables increased substantially with the passage of time and were in reverse proportion to the placement angles, which indicates a concentration of particles, as well as physical and chemical changes.展开更多
In this study,a CO_(2) capture material in the form of liquid-like adsorbents(LLAs) is developed to overcome the limitations of conventional types of adsorbents.The increase in indoor activities necessitates the captu...In this study,a CO_(2) capture material in the form of liquid-like adsorbents(LLAs) is developed to overcome the limitations of conventional types of adsorbents.The increase in indoor activities necessitates the capture of CO_(2) in enclosed indoor spaces.Indoor spaces require safe and stable materials for CO_(2) capture because humans are present in these spaces.Solid adsorbents are mainly used because liquid absorbents are unsuitable owing to noise and scattering problems.In LLA,the liquid absorbent assembled by carbon nanotubes(CNTs) is solidified and prevented from flowing and scattering indoor.LLAs present to maintain 95% of initial capacity after recycling 20 times,and have characteristics that can be regenerated in a low temperature heat source(80 to 120℃) and moisture resistance.This work not only provides indoor useable CO_(2) capture materials,but also offers a new prospect in the field of adsorbents.展开更多
Objective Evidence on potential cardiovascular benefits of personal-level intervention among the elderly exposed to high levels of particulate matter(PM)remains limited.We aimed to assess improvements in surrogate mar...Objective Evidence on potential cardiovascular benefits of personal-level intervention among the elderly exposed to high levels of particulate matter(PM)remains limited.We aimed to assess improvements in surrogate markers of cardiovascular injury in vulnerable populations at risks by using indoor air filtration units.Methods We conducted a randomized crossover trial for 2 separate 2-week air filtration interventions in 20 households of patients with stable chronic obstructive pulmonary disease and their partners in the winter of 2013,with concurrent measurements of indoor PM.The changes in biomarkers indicative of cardiac injury,atherosclerosis progression and systemic inflammation following intervention were evaluated using linear mixed-effect models.Results In the analysis,average levels of indoor PM with aerodynamic diameters<2.5µm(PM2.5)decreased significantly by 59.2%(from 59.6 to 24.3µg/m3,P<0.001)during the active air filtration.The reduction was accompanied by improvements in levels of high-sensitivity cardiac troponin I by−84.6%(95%confidence interval[CI]:−90.7 to−78.6),growth differentiation factor-15 by−48.1%(95%CI:−31.2 to−25.6),osteoprotegerin by−65.4%(95%CI:−56.5 to−18.7),interleukin-4 by−46.6%(95%CI:−62.3 to−31.0)and myeloperoxidase by−60.3%(95%CI:−83.7 to−3.0),respectively.Conclusion Indoor air filtration intervention may provide potential cardiovascular benefits in vulnerable populations at risks.展开更多
Background: Indoor air quality in environments where there is great circulation of people, posing risks to the health of its occupants, including allergic problems, infections and contaminations, can be aided by clima...Background: Indoor air quality in environments where there is great circulation of people, posing risks to the health of its occupants, including allergic problems, infections and contaminations, can be aided by climatic factors, chemicals and biological agents housed in these environments, influencing the location and providing favorable conditions for the degradation of bibliographic collections. The present study investigated the presence of fungi in indoor environments in seven public and private libraries in the central region of Brazil, Mato Grosso, and verified the impact on occupational health. Results: A total of 26,194 fungal specimens were isolated from 342 dust samples collected using three techniques: Andersen’s sampler (12.3%), exposure plate dish (25.1%) and sterile swab (62.6%). A total of 184 fungal species were identified: 156 (84.8%) mycelial fungi and 28 (15.2%) yeast fungi, belonging 54 fungal genera, 43 (79.6%) mycelial fungi and 11 (20.4%) yeast fungi. The genus Aspergillus (40.6%) was one of the main fungi present in indoor air. Aspergillus niger (12.3%) was identified as the most prevalent species in literary environments, followed by Cryptococcus spp. (7.1%) and Cladosporium cladosporioides (7.0%). In relation to seasonal distribution, there was a greater fungal isolation in the dry season (54%);followed by the rainy season (46%). Conclusion: These results suggest the substrates researched in the evaluated environments presented in the form of documents, books and papers associated with dust and air humidity become suitable for microbiological proliferation. These findings highlight the importance of minimizing the risk of exposure to fungal agents, identified in pathogenic and toxigenic microenvironments in library collections.展开更多
Objective The study was designed to compare the combustion products of coal gas, liquefied petroleum gas and natural gas in relation to indoor air pollution. Methods Regular pollutants including B(a)P were monitored a...Objective The study was designed to compare the combustion products of coal gas, liquefied petroleum gas and natural gas in relation to indoor air pollution. Methods Regular pollutants including B(a)P were monitored and 1-hydroxy pyrene were tested in urine of the enrolled subjects. Radon concentrations and their changes in four seasons were also monitored in the city natural gas from its source plant and transfer stations to final users. To analyze organic components of coal gas, liquefied petroleum gas and natural gas, a high-flow sampling device specially designed was used to collect their combustion products, and semi-volatile organic compounds contained in the particles were detected by gas chromatograph-mass spectrograph (GC/MS). Results Findings in the study showed that the regular indoor air pollutants particles and CO were all above the standard in winter when heating facilities were operated in the city, but they were lowest in kitchens using natural gas; furthermore, although NO2 and CO2 were slightly higher in natural gas, B(a)P concentration was lower in this group and 1-hydroxy pyrene was lowest in urine of the subjects exposed to natural gas. Organic compounds were more complicated in coal gas and liquefied petroleum gas than in natural gas. The concentration of radon in natural gas accounted for less than 1‰ of its effective dose contributing to indoor air pollution in Beijing households. Conclusion Compared to traditional fuels, gases are deemed as clean ones, and natural gas is shown to be cleaner than the other two gases.展开更多
Increasing incidents of indoor air quality(IAQ) related complaints lead us to the fact that IAQ has become a significant occupational health and environmental issue. However, how to effectively evaluate IAQ under diff...Increasing incidents of indoor air quality(IAQ) related complaints lead us to the fact that IAQ has become a significant occupational health and environmental issue. However, how to effectively evaluate IAQ under different scale of multiple indicators is still a challenge. The traditional single-indicator method is subjected to uncertainties in assessing IAQ due to different subjectivity on good or bad quality and scalar differences of data set. In this study, a multilevel integrated weighted average IAQ method including initial walking through assessment(IWA) and two-layers weighted average method are developed and applied to evaluate IAQ of the laboratory building at the University of Regina in Canada. Some important chemical parameters related to IAQ in terms of volatile organic compounds(VOCs), methanol(HCHO), carbon dioxide(CO2), and carbon monoxide(CO) are evaluated based on 5 months continuous monitoring data. The new integrated assessment result can not only indicates the risk of an individual parameter, but also able to quantify the overall IAQ risk on the sampling site. Finally, some recommendations based on the result are proposed to address sustainable IAQ practices in the sampling area.展开更多
Providing comfortable indoor air quality control in residential construction is an exceedingly important issue.This is due to the structure of the fast response controller of air quality.The presented work shows the b...Providing comfortable indoor air quality control in residential construction is an exceedingly important issue.This is due to the structure of the fast response controller of air quality.The presented work shows the breakdown and creation of a mathematical model for an interactive,nonlinear system for the required comfortable air quality.Furthermore,the paper refers to designing traditional proportional integral derivative regulators and proportional,integral,derivative regulators with independent parameters based on a backpropagation neural network.In the end,we perform the experimental outputs of a suggested backpropagation neural network-based proportional,integral,derivative controller and analyze model results by applying the proposed system.The obtained results demonstrated that the proposed controller can provide the required level of clean air in the room.The proposed developed model takes into consideration international Heating,Refrigerating,and air conditioning standards as ASHRAE AND ISO.Based on the findings,we concluded that it is possible to implement a proposed system in homes and offer equivalent indoor air quality with continuous mechanical ventilation without a profuse amount of energy.展开更多
Three representative types of houses in Beijing were selected and, in each type, smoking and nonsmoking households were compared. IP, RP. and CO concentrations in the living room and kitchen were monitored during each...Three representative types of houses in Beijing were selected and, in each type, smoking and nonsmoking households were compared. IP, RP. and CO concentrations in the living room and kitchen were monitored during each season. and the level of COHb in the heads of the households were measured. The study showed that indoor air pollution was rather severe, especially during winter. when paniculate concentrations markedly exceeded the standard and CO concentration was as high as 47 ppm. Indoor air pollution was closely related to the type of house, particularly to the mode of heating. In houses. of the same type, pollution improved greatly after central heating facilities were installed. Analysis of 30 elements revealed that pollution was typically caused by coal burning. aggravated by dusty wind, but high indoor Pb levels were probably due to the use of LPG for cooking. In our study the effect of cigarette smoking was sometimes masked by the severe indoor pollution. (C)1990 Academic Press, Inc.展开更多
The study was conducted to identify indoor air quality and the level of thermal comfort in various selected locations in Faculty of Engineering and Built Environment （FKAB）, University Kebangsaan Malaysia （UKM） wi...The study was conducted to identify indoor air quality and the level of thermal comfort in various selected locations in Faculty of Engineering and Built Environment （FKAB）, University Kebangsaan Malaysia （UKM） with built-up area of 250,936 fie. The indoor air quality and thermal comfort were measured at various selected locations by using indoor air quality equipment （Thermal Comfort SERI）. The thermal comfort assessments are based on Malaysian Code of Practice Indoor Air Quality 2005 and Moderate Thermal Environments-Determination of the PMV and PPD indices specification of the condition for thermal comfort （ISO7730：1994） From the data analysis, the FKAB building is considered inadequately vented space. The concentration of CO2 for all sampling area evaluated exceeds the recommended concentration （〉 1000 ppm）. The ventilation system used in FKAB building is designed by delivering fix amount of fresh air into building from external building without consideration on the number of occupants. This common ventilation design will increase the amount of CO2 dramatically all day long and these reflect the inefficiency of energy used. The faculty needs to be equipped with a comprehensive energy management system that can allow detailed documentation of continuous performance of all energy system and consumption in the building.展开更多
Latvian children under the age of 7 can spend up to 60 hours per week in daycare centers and therefore it is very important to establish a healthy and comfortable daycare environment that children will find pleasant a...Latvian children under the age of 7 can spend up to 60 hours per week in daycare centers and therefore it is very important to establish a healthy and comfortable daycare environment that children will find pleasant and stimulating to stay in. This study investigates indoor air quality and thermal comfort within six daycare centers （old, renovated and new-built） in moderate climate zone of Latvia. Measurements of carbon dioxide, air temperature and relative humidity were carried out, and data regarding daycare center characteristics and maintenance activities was collected via combination of field visits, record analysis and interviews. It was found that carbon dioxide concentrations exceeded 1000 ppm in 75% of daycare centers studied, with the highest （1356 ppm） measured in a renovated facility with the natural ventilation system. Thus installation of more efficient ventilation system （mechanical） is recommended to provide acceptable indoor air quality, since opening of windows itself cannot provide the optimal conditions indoors. In all facilities the temperature was kept above 20℃ and the average relative humidity was 40±35%, creating comfortable thermal environment for children.展开更多
Complaints on the indoor environment of the residents in recent decades have become a common problem in the Swedish housing. The buildings themselves are said to be the cause of problems, and it is given a vague pictu...Complaints on the indoor environment of the residents in recent decades have become a common problem in the Swedish housing. The buildings themselves are said to be the cause of problems, and it is given a vague picture of both the exposure and the effect of the problems. The symptoms that residents and users state are often common in the population such as headache, fatigue, mucosal disorders and skin problems. It must be considered that the air that people routinely inhale contains impurities of various kinds, both in- and outdoors. An important source of contamination indoors is the microorganisms that are pathogenic, so called agents. Examples of infectious agents are viruses, fungi, bacteria and protozoa. The purpose of this project is to examine whether a physical measurement is possible to obtain for identifying a possible threshold level of air pollution in the indoor environment. In this study, carried out through physical measurements, the results show major deficiencies in the Swedish school environment. If we study the emissions in the important health-related size range of particles larger than 5.0 microns, before and after measures, the environmental benefits are clarified since over 90% of contaminants larger than 5.0 microns have been eliminated.展开更多
2022 Indoor Air Quality(IAQ),particularly in educational facilities,is gaining considerable interest and is a synonymous indicator towards evaluating human comfort.Factors such as CO_(2) concentration,temperature,and ...2022 Indoor Air Quality(IAQ),particularly in educational facilities,is gaining considerable interest and is a synonymous indicator towards evaluating human comfort.Factors such as CO_(2) concentration,temperature,and humidity play crucial parts in determining an acceptable level of IAQ.Many studies have also demonstrated that the indoor air quality of classrooms affects students’concentration and performance.Today with the threat of a global pandemic,the demand of clean&fresh indoor air quality in education buildings is extremely intensive.This study focuses on investigating IAQ situations and changes in different typical functional spaces of a higher education building in the UK.CO_(2),temperature,and humidity data in various learning environment were monitored via data loggers during the winter.Associated with data monitoring,a set of questionnaires surveys were carried out to evaluate the user’s experience.The results of this study show that temperature and CO_(2) concentration in the classrooms was constantly higher than the government guidance on a daily basis.The analysis also shows that temperature and humidity increased with CO_(2) levels,but at a much lower rate.This study has revealed poor and concerning IAQ in higher education buildings in the UK,particularly in larger rooms with high occupancy.Along with the findings,this paper also identifies possible impact or factors and proposes solutions to overcome these issues.展开更多
文摘This study aims to optimize the influence of the inlet inclination angle on the Indoor Air Quality(IAQ),heat,and temperature distribution in mixed convection within a two-dimensional square cavityfilled with an air-CO_(2)mixture.The air-CO_(2)mixture enters the cavity through two inlet openings positioned at the top wall,which is set at the ambient temperature(TC).Three values of the Reynolds numbers,ranging from 1000 to 2000,are considered,while the Prandtl number is kept constant(Pr=0.71).The temperature distribution and streamlines are shown for Rayleigh number(Ra)equal to 104,three inlet inclination anglesϕ(0,π/6 andπ/4)and three CO_(2)concentrations values(1500,2500,3500 ppm)applied at both hot vertical walls(maintained at a constant temperature TH).Afinite volume method is used under the assumption of two-dimensional laminarflow to solve the NavierStokes and energy equations.The results indicate that inlet inclination angle has an impact on the indoor air quality(IAQ),which,in turn,affects the heat transfer distribution and thermal comfort within the cavity.
基金supported by the Project“Entrepreneurial competences and excellence research in doctoral and postdoctoral programs-ANTREDOC”,project cofounded by the European Social Fund financing agreement No.56437/24.07.2019.
文摘The amount of moisture in the air is represented by relative humidity(RH);an ideal level of humidity in the interior environment is between 40%and 60%at temperatures between 18°and 20°Celsius.When the RH falls below this level,the environment becomes dry,which can cause skin dryness,irritation,and discomfort at low temperatures.When the humidity level rises above 60%,a wet atmosphere develops,which encourages the growth of mold and mites.Asthma and allergy symptoms may occur as a result.Human health is harmed by excessive humidity or a lack thereof.Dehumidifiers can be used to provide an optimal level of humidity and a stable and pleasant atmosphere;certain models disinfect and purify the water,reducing the spread of bacteria.The design and implementation of a client-server indoor and outdoor air quality monitoring application are presented in this paper.The Netatmo station was used to acquire the data needed in the application.The client is an Android application that allows the user to monitor air quality over a period of their choosing.For a good monitoring process,the Netatmo modules were used to collect data from both environments(indoor:temperature(T),RH,carbon dioxide(CO_(2)),atmospheric pressure(Pa),noise and outdoor:T and RH).The data is stored in a database,using MySQL.The Android application allows the user to view the evolution of the measured parameters in the form of graphs.Also,the paper presents a prediction model of RH using Azure Machine Learning Studio(Azure ML Studio).The model is evaluated using metrics:Mean Absolute Error(MAE),Root Mean Squared Error(RMSE),Relative Absolute Error(RAE),Relative Squared Error(RSE)and Coefficient of Determination(CoD).
文摘Besides the need for low-cost instruments for air pollution measurement and detection,nowadays there are many concerns about air pollution due to the fast changes and used technologies.This research was applied using an MQ2 gas detector,and microcontroller/Arduino-Uno.The design steps included bonding and connecting readymade sensors,coding,and finally testing the device.Testing has been conducted in Environment and Pollution Engineering Department laboratories,at the Technical Engineering College of Kirkuk.This study proposed the use of an MQ2 sensor for multi-gas rate detection which can exist indoors.The system uses also a DHT22 sensor for measuring environment temperature and humidity.The sensors are connected to Arduino and LCD to present data on LCD by powering the system with external power.Overall,the testing was conducted,and the device served as a measuring tool for indoor air as an accurate multi-gas rate detector.
文摘Individuals spend 90% of their time indoors, primarily at home or at work. Indoor environmental factors have a significant impact on human well-being. It was a longitudinal study that assessed the major factors that reduce indoor air quality, namely particulate matter, and bio-aerosols, using low-cost sensors and the settle plate method, respectively also to determine the effect of atmospheric parameters and land use patterns in households of commercial, industrial, residential, slum, and rural areas of the city. PM2.5 concentration levels were similar in most parts of the day across all sites. PM10.0 concentration levels increased indoors in a commercial area. PM2.5 concentration showed a negative correlation with temperature and a positive correlation with relative humidity in some areas. Very high values of PM2.5 concentration and PM10.0 concentration have been observed in this study, inside households of selected rural and urban areas. Pathogenic gram-positive cocci, gram-positive rods, Aspergillus, and Mucor species were the most common bacterial and fungal species respectively found inside households. This study examined particulate matter concentration along with bio-aerosols, as very less studies have been conducted in Jaipur the capital of Rajasthan, a state in the western part of India which assessed both of these factors together to determine the indoor air quality. Rural households surrounding the periphery of the city were found to have similar pollution levels as urban households. So, this study may form the basis for reducing pollution inside households and also for taking suitable measures for the reduction of pollution in the indoor environment.
基金The National Natural Science Foundation of China(No.50878078)
文摘To study the indoor air qualities（IAQ）of large commercial office buildings in Hunan province of China and the corresponding improvement methods,the IAQ of a large commercial office building in Changsha in July,2008,is investigated.A questionnaire survey and field tests are used to collect data.According to the data of twelve rooms in this building,objective evaluation and the subjective evaluation of the IAQ are obtained.Almost all of the environmental parameters in these rooms basically meet the standards of the objective evaluation.But the average concentration of carbon dioxide in most rooms cannot reach the value of the cleanliness standards,1 255 mg/m^3.The average acceptability of the IAQ in these rooms is 71%,which is lower than the value of the ASHRAE 55—1992 standards,80%.The proper increase in the wind speed and the indoor fresh air supply can greatly improve the objective evaluation and the subjective evaluation of the IAQ.
文摘A methodology for identifying volatile organic compounds （VOCs） and determining air quality of indoor air has been developed. The air samples are collected using pump samplers by the inhabitants when they perceive odorous and/or discomfort episodes. Glass multi-sorbent tubes are connected to the pump samplers for the retention of VOC. The analysis is performed by automatic thermal desorption （ATD） coupled with gas chromatography-mass spectrometry （GC/MS）. This methodology can be applied in cases of sick building syndrome （SBS） evaluation, in which building occupants experience a series of varied symptoms that appear to be linked to time spent in the building. Chemical pollutants concentrations （e.g., VOC） have been described to contribute to SBS. To exemplify the methodology, a qualitative determination and an evaluation of existing VOC were performed in a dwelling where the occupants experienced the SBS symptoms. Higher total VOC （TVOC） levels were detected during episodes in indoor air （1.33 ±1.53 mg/m^3） compared to outdoor air （0.71± 0.46 mg/m^3）. The concentrations of individual VOCs, such as ethanol, acetone, isopropanol, 1-butanol, acetic acid, acetonitrile and 1-methoxy-2-propanol, were also higher than the expected for a standard dwelling. The external source of VOC was found to be an undeclared activity of storage and manipulation of solvents located at the bottom of a contiguous building.
基金supported by a Kawasaki Medical School Research Grant(28B051)
文摘Objective The changes in serum adipokines and cytokines related to oxidative stress were examined during 3 months ‘Off to On’ and ‘On to Off’ periods using negatively charged particle-dominant indoor air conditions（NCPDIAC）.Methods Seven volunteers participated in the study,which included ‘OFF to 3 months ON’ periods（ON trials） for a total of 16 times,and ‘ON to 3 months OFF’（OFF trials） periods for a total of 13 times.Results With the exception of one case,serum amyloid A（SAA） levels decreased significantly during the ON trials.Conclusion Considering that SAA is an acute phase reactive protein such as C reactive protein（CRP）,this observed decrease might indicate the prevention of cardiovascular and atherosclerotic changes,since an increase in high-sensitive CRP is associated with the subsequent detection of these events.
基金supported by a research grant from the Research Grant Council of the Hong Kong SAR Government, China
文摘This is the first detailed characterization of the airborne bacterial profiles in indoor environments. Two restaurants were selected for this study. Fifteen genera of bacteria were isolated from each restaurant and identified by three different bacterial identification systems including MIDI, Biolog and Riboprinter. The dominant bacteria of both restaurants were Gram-positive bacteria in which Micrococcus and Bacillus species were the most abundant. Most bacteria identified were representative species of skin and respiratory tract of human, and soil. Although the bacterial levels in these two restaurants were below the limit of the Hong Kong Indoor Air Quality Objective （HKIAQO） Level 1 standard （i.e., 〈 500 cfu/m^3）, the majority of these bacteria were opportunistic pathogens. These results suggested that the identity of airborne bacteria should also be included in the IAQ to ensure there is a safety guideline for the public.
基金Projects 50474050 supported by the National Natural Science Foundation of China 20040533011 by the Doctoral Fund of Ministry of Education of China
文摘Experiments on the behavior of airborne microparticle sediments and their adhesion on glass slides were conducted in a laboratory located on the first floor of a teaching building. Clean tiles and glass slides were placed at different angles （0°, 45° and 90°） with respect to the horizontal plane in the laboratory. The sedimentation of microparticles was investigated at certain time intervals （1 d, 3 d, l0 d and 30 d）. The results of testing, at day 30, show that the diameters of particles on the horizontal tiles varied from 20 to 80 μm; few particles with diameter less than 0.5 μm or greater than 100 μm were found. The amount of particle sediment on all the slides increased along over time, while the average diameter of particles was not correlated with time, nor with the angle of placement. The maximum particle size, the total particle surface area, the total perimeter of all particles and the cover ratio of light （the proportion of total area of particles to the observed area of the slides surfaces） did not change significantly within the first 10 days. Inspection of all the samples for the last 20 days, however, showed that these variables increased substantially with the passage of time and were in reverse proportion to the placement angles, which indicates a concentration of particles, as well as physical and chemical changes.
基金supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT)(Grant number:2020R1A5A1018153 and No.2020R1A6A3A01095950)。
文摘In this study,a CO_(2) capture material in the form of liquid-like adsorbents(LLAs) is developed to overcome the limitations of conventional types of adsorbents.The increase in indoor activities necessitates the capture of CO_(2) in enclosed indoor spaces.Indoor spaces require safe and stable materials for CO_(2) capture because humans are present in these spaces.Solid adsorbents are mainly used because liquid absorbents are unsuitable owing to noise and scattering problems.In LLA,the liquid absorbent assembled by carbon nanotubes(CNTs) is solidified and prevented from flowing and scattering indoor.LLAs present to maintain 95% of initial capacity after recycling 20 times,and have characteristics that can be regenerated in a low temperature heat source(80 to 120℃) and moisture resistance.This work not only provides indoor useable CO_(2) capture materials,but also offers a new prospect in the field of adsorbents.
基金This work was supported by Beijing Natural Science Foundation(7222246)Royal Dutch Philips Electronics Ltd.(Grant NL18-2100478471).
文摘Objective Evidence on potential cardiovascular benefits of personal-level intervention among the elderly exposed to high levels of particulate matter(PM)remains limited.We aimed to assess improvements in surrogate markers of cardiovascular injury in vulnerable populations at risks by using indoor air filtration units.Methods We conducted a randomized crossover trial for 2 separate 2-week air filtration interventions in 20 households of patients with stable chronic obstructive pulmonary disease and their partners in the winter of 2013,with concurrent measurements of indoor PM.The changes in biomarkers indicative of cardiac injury,atherosclerosis progression and systemic inflammation following intervention were evaluated using linear mixed-effect models.Results In the analysis,average levels of indoor PM with aerodynamic diameters<2.5µm(PM2.5)decreased significantly by 59.2%(from 59.6 to 24.3µg/m3,P<0.001)during the active air filtration.The reduction was accompanied by improvements in levels of high-sensitivity cardiac troponin I by−84.6%(95%confidence interval[CI]:−90.7 to−78.6),growth differentiation factor-15 by−48.1%(95%CI:−31.2 to−25.6),osteoprotegerin by−65.4%(95%CI:−56.5 to−18.7),interleukin-4 by−46.6%(95%CI:−62.3 to−31.0)and myeloperoxidase by−60.3%(95%CI:−83.7 to−3.0),respectively.Conclusion Indoor air filtration intervention may provide potential cardiovascular benefits in vulnerable populations at risks.
基金provided by the Research Foundation of the State of Mato Grosso(Fundacao de Amparo a Pesquisa no Estado de Mato Grosso,FAPEMAT)and Coordination of Improvement of Higher Level Personnel(Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior,CAPES).
文摘Background: Indoor air quality in environments where there is great circulation of people, posing risks to the health of its occupants, including allergic problems, infections and contaminations, can be aided by climatic factors, chemicals and biological agents housed in these environments, influencing the location and providing favorable conditions for the degradation of bibliographic collections. The present study investigated the presence of fungi in indoor environments in seven public and private libraries in the central region of Brazil, Mato Grosso, and verified the impact on occupational health. Results: A total of 26,194 fungal specimens were isolated from 342 dust samples collected using three techniques: Andersen’s sampler (12.3%), exposure plate dish (25.1%) and sterile swab (62.6%). A total of 184 fungal species were identified: 156 (84.8%) mycelial fungi and 28 (15.2%) yeast fungi, belonging 54 fungal genera, 43 (79.6%) mycelial fungi and 11 (20.4%) yeast fungi. The genus Aspergillus (40.6%) was one of the main fungi present in indoor air. Aspergillus niger (12.3%) was identified as the most prevalent species in literary environments, followed by Cryptococcus spp. (7.1%) and Cladosporium cladosporioides (7.0%). In relation to seasonal distribution, there was a greater fungal isolation in the dry season (54%);followed by the rainy season (46%). Conclusion: These results suggest the substrates researched in the evaluated environments presented in the form of documents, books and papers associated with dust and air humidity become suitable for microbiological proliferation. These findings highlight the importance of minimizing the risk of exposure to fungal agents, identified in pathogenic and toxigenic microenvironments in library collections.
文摘Objective The study was designed to compare the combustion products of coal gas, liquefied petroleum gas and natural gas in relation to indoor air pollution. Methods Regular pollutants including B(a)P were monitored and 1-hydroxy pyrene were tested in urine of the enrolled subjects. Radon concentrations and their changes in four seasons were also monitored in the city natural gas from its source plant and transfer stations to final users. To analyze organic components of coal gas, liquefied petroleum gas and natural gas, a high-flow sampling device specially designed was used to collect their combustion products, and semi-volatile organic compounds contained in the particles were detected by gas chromatograph-mass spectrograph (GC/MS). Results Findings in the study showed that the regular indoor air pollutants particles and CO were all above the standard in winter when heating facilities were operated in the city, but they were lowest in kitchens using natural gas; furthermore, although NO2 and CO2 were slightly higher in natural gas, B(a)P concentration was lower in this group and 1-hydroxy pyrene was lowest in urine of the subjects exposed to natural gas. Organic compounds were more complicated in coal gas and liquefied petroleum gas than in natural gas. The concentration of radon in natural gas accounted for less than 1‰ of its effective dose contributing to indoor air pollution in Beijing households. Conclusion Compared to traditional fuels, gases are deemed as clean ones, and natural gas is shown to be cleaner than the other two gases.
文摘Increasing incidents of indoor air quality(IAQ) related complaints lead us to the fact that IAQ has become a significant occupational health and environmental issue. However, how to effectively evaluate IAQ under different scale of multiple indicators is still a challenge. The traditional single-indicator method is subjected to uncertainties in assessing IAQ due to different subjectivity on good or bad quality and scalar differences of data set. In this study, a multilevel integrated weighted average IAQ method including initial walking through assessment(IWA) and two-layers weighted average method are developed and applied to evaluate IAQ of the laboratory building at the University of Regina in Canada. Some important chemical parameters related to IAQ in terms of volatile organic compounds(VOCs), methanol(HCHO), carbon dioxide(CO2), and carbon monoxide(CO) are evaluated based on 5 months continuous monitoring data. The new integrated assessment result can not only indicates the risk of an individual parameter, but also able to quantify the overall IAQ risk on the sampling site. Finally, some recommendations based on the result are proposed to address sustainable IAQ practices in the sampling area.
文摘Providing comfortable indoor air quality control in residential construction is an exceedingly important issue.This is due to the structure of the fast response controller of air quality.The presented work shows the breakdown and creation of a mathematical model for an interactive,nonlinear system for the required comfortable air quality.Furthermore,the paper refers to designing traditional proportional integral derivative regulators and proportional,integral,derivative regulators with independent parameters based on a backpropagation neural network.In the end,we perform the experimental outputs of a suggested backpropagation neural network-based proportional,integral,derivative controller and analyze model results by applying the proposed system.The obtained results demonstrated that the proposed controller can provide the required level of clean air in the room.The proposed developed model takes into consideration international Heating,Refrigerating,and air conditioning standards as ASHRAE AND ISO.Based on the findings,we concluded that it is possible to implement a proposed system in homes and offer equivalent indoor air quality with continuous mechanical ventilation without a profuse amount of energy.
文摘Three representative types of houses in Beijing were selected and, in each type, smoking and nonsmoking households were compared. IP, RP. and CO concentrations in the living room and kitchen were monitored during each season. and the level of COHb in the heads of the households were measured. The study showed that indoor air pollution was rather severe, especially during winter. when paniculate concentrations markedly exceeded the standard and CO concentration was as high as 47 ppm. Indoor air pollution was closely related to the type of house, particularly to the mode of heating. In houses. of the same type, pollution improved greatly after central heating facilities were installed. Analysis of 30 elements revealed that pollution was typically caused by coal burning. aggravated by dusty wind, but high indoor Pb levels were probably due to the use of LPG for cooking. In our study the effect of cigarette smoking was sometimes masked by the severe indoor pollution. (C)1990 Academic Press, Inc.
文摘The study was conducted to identify indoor air quality and the level of thermal comfort in various selected locations in Faculty of Engineering and Built Environment （FKAB）, University Kebangsaan Malaysia （UKM） with built-up area of 250,936 fie. The indoor air quality and thermal comfort were measured at various selected locations by using indoor air quality equipment （Thermal Comfort SERI）. The thermal comfort assessments are based on Malaysian Code of Practice Indoor Air Quality 2005 and Moderate Thermal Environments-Determination of the PMV and PPD indices specification of the condition for thermal comfort （ISO7730：1994） From the data analysis, the FKAB building is considered inadequately vented space. The concentration of CO2 for all sampling area evaluated exceeds the recommended concentration （〉 1000 ppm）. The ventilation system used in FKAB building is designed by delivering fix amount of fresh air into building from external building without consideration on the number of occupants. This common ventilation design will increase the amount of CO2 dramatically all day long and these reflect the inefficiency of energy used. The faculty needs to be equipped with a comprehensive energy management system that can allow detailed documentation of continuous performance of all energy system and consumption in the building.
文摘Latvian children under the age of 7 can spend up to 60 hours per week in daycare centers and therefore it is very important to establish a healthy and comfortable daycare environment that children will find pleasant and stimulating to stay in. This study investigates indoor air quality and thermal comfort within six daycare centers （old, renovated and new-built） in moderate climate zone of Latvia. Measurements of carbon dioxide, air temperature and relative humidity were carried out, and data regarding daycare center characteristics and maintenance activities was collected via combination of field visits, record analysis and interviews. It was found that carbon dioxide concentrations exceeded 1000 ppm in 75% of daycare centers studied, with the highest （1356 ppm） measured in a renovated facility with the natural ventilation system. Thus installation of more efficient ventilation system （mechanical） is recommended to provide acceptable indoor air quality, since opening of windows itself cannot provide the optimal conditions indoors. In all facilities the temperature was kept above 20℃ and the average relative humidity was 40±35%, creating comfortable thermal environment for children.
文摘Complaints on the indoor environment of the residents in recent decades have become a common problem in the Swedish housing. The buildings themselves are said to be the cause of problems, and it is given a vague picture of both the exposure and the effect of the problems. The symptoms that residents and users state are often common in the population such as headache, fatigue, mucosal disorders and skin problems. It must be considered that the air that people routinely inhale contains impurities of various kinds, both in- and outdoors. An important source of contamination indoors is the microorganisms that are pathogenic, so called agents. Examples of infectious agents are viruses, fungi, bacteria and protozoa. The purpose of this project is to examine whether a physical measurement is possible to obtain for identifying a possible threshold level of air pollution in the indoor environment. In this study, carried out through physical measurements, the results show major deficiencies in the Swedish school environment. If we study the emissions in the important health-related size range of particles larger than 5.0 microns, before and after measures, the environmental benefits are clarified since over 90% of contaminants larger than 5.0 microns have been eliminated.
文摘2022 Indoor Air Quality(IAQ),particularly in educational facilities,is gaining considerable interest and is a synonymous indicator towards evaluating human comfort.Factors such as CO_(2) concentration,temperature,and humidity play crucial parts in determining an acceptable level of IAQ.Many studies have also demonstrated that the indoor air quality of classrooms affects students’concentration and performance.Today with the threat of a global pandemic,the demand of clean&fresh indoor air quality in education buildings is extremely intensive.This study focuses on investigating IAQ situations and changes in different typical functional spaces of a higher education building in the UK.CO_(2),temperature,and humidity data in various learning environment were monitored via data loggers during the winter.Associated with data monitoring,a set of questionnaires surveys were carried out to evaluate the user’s experience.The results of this study show that temperature and CO_(2) concentration in the classrooms was constantly higher than the government guidance on a daily basis.The analysis also shows that temperature and humidity increased with CO_(2) levels,but at a much lower rate.This study has revealed poor and concerning IAQ in higher education buildings in the UK,particularly in larger rooms with high occupancy.Along with the findings,this paper also identifies possible impact or factors and proposes solutions to overcome these issues.
