Monitoring and Prediction of Indoor Air Quality for Enhanced Occupational Health

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).

Indoor Air Pollution and Its Determinants in Household Settings in Jaipur, India

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.

Design of Multi-gas Monitoring Device for Indoor Air Quality

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.

A Natural Catalytic Converter® for Continuously Inactivating Air and Surface Pathogens with More Effect than Ventilation and Filtration

Study Objective: The purpose of the study is to present independent laboratory testing for a novel technology in air and on surfaces. Since 2020, public health goals have focused on improving indoor air quality. This includes protection from airborne pathogens, such as tuberculosis, RSV, SARS-CoV-2, common cold or influenza viruses, measles, and others. Engineering controls are highly effective at reducing hazardous pathogens found in indoor air and from recontamination of surfaces. This occurs from a continuous cycle of settling of small, sustained airborne pathogens, which may become dehumidified, becoming airborne again, carried by room air currents around indoor spaces, then repeating the cycle. Methods: The novel technology utilizes a catalytic process to produce safe levels of hydrogen peroxide gas that are effective in reducing pathogens in the air and on surfaces. Air testing was performed with the MS2 bacteriophage, the test organism for ASHRAE standard 241, and methicillin-Resistant Staphylococcus aureus (MRSA). Surface testing was performed with SARS-COV-2 (Coronavirus COVID-19) and H1N1 (Influenza). Typical ventilation and filtration does not effectively remove disbursed pathogens from the entire facility, due to inconsistent air circulation and surface deposits of pathogens. Results: MS2 was reduced by 99.9%;MRSA was reduced by 99.9%;SARS-CoV-2 was reduced by 99.9%;H1N1 was reduced by 99.9%. Conclusion: This novel catalytic converter reduces a variety of pathogens in the air (99%) and on surfaces (99%), by actively disinfecting with the introduction of gaseous hydrogen peroxide. This active disinfection provides a strong solution for protecting the entire facility and its occupants.

Comprehensive Analysis of Indoor Formaldehyde Removal Techniques:Exploring Physical,Chemical,and Biological Methods

This research focuses on the evaluation of diverse approaches for removing formaldehyde from indoor environments,which is a significant concern for indoor air quality.The study systematically examines physical,chemical,and biological methods to ascertain their effectiveness in formaldehyde mitigation.Physical methods,including air circulation and adsorption,particularly with activated carbon and molecular sieves,are assessed for their efficiency in various concentration scenarios.Chemical methods,such as photocatalytic oxidation using titanium dioxide and plasma technology,are analyzed for their ability to decompose formaldehyde into non-toxic substances.Additionally,biological methods involving plant purification and microbial transformation are explored for their eco-friendly and sustainable removal capabilities.The paper concludes that while each method has its merits,a combined approach may offer the most effective solution for reducing indoor formaldehyde levels.The study underscores the need for further research to integrate these methods in a practical,cost-effective,and environmentally sustainable manner,highlighting their potential to improve indoor air quality significantly.

基于Airpak的幼儿园生活单元空气质量模拟分析

通过对幼儿园生活单元建立物理数学模型,基于Airpak模拟分析了排风量、新风量、新风口位置以及室外风速对室内空气品质的影响。结果表明,门窗关闭的室内,仅设置排风并不能有效降低室内CO_(2)平均浓度;引入新风对降低室内CO_(2)平均浓度效果显著;新风口距离人员越近,并非越有利于降低室内CO_(2)平均浓度;过渡季节,开启门窗室内CO_(2)平均浓度水平明显降低。

Determining indoor air quality and identifying the origin of odour episodes in indoor environments

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.

Comprehensive characterization of indoor airborne bacterial profile

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.

Decrease in Serum Amyloid a Protein Levels Following Three-month Stays in Negatively Charged Particle-dominant Indoor Air Conditions

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.

Microbiological assessment of indoor air of a teaching hospital in Nigeria

Objective:To investigate the quality of indoor air of different wards and units of Olabisi Onabanjo University Teaching Hospital, Sagamu, to ascertain their contribution to infection rate in the hospital.Methods:The microbial quality of indoor air of nine wards/units of Olabisi Onabanjo University Teaching Hospital, Sagamu, Nigeria was conducted. Sedimentation technique using open Petri-dishes containing different culture media was employed and samplings were done twice daily, one in the morning shortly after cleaning and before influx of people/patients into the wards/units and the other in the evening when a lot of activities would have taken place in these wards. Isolates were identified according to standard methods.Results:Results showed that there was a statistically significant difference(氈2= 6.0167) in the bacteria population of the different sampling time whereas it was not so for fungi population(氈2= 0.2857). Male medical ward(MMW) and male surgical general(MSG) recorded the highest bacterial and fungal growth while the operating theatre(OT) was almost free of microbial burden. The bacteria isolates were Staphylococcus aureus, Klebsiellasp., Bacillus cereus, Bacillus subtilis, Streptococcus pyogenes andSerratia marscenceswhile the fungi isolates includedAspergillus flavus, Penicilliumsp.,Fusariumsp.,Candida albicansandAlternariasp.Staphylococcus aureuswas the predominantly isolated bacterium whilePenicilliumsp. was the most isolated fungus.Conclusions:Though most of the microbial isolates were potential and or opportunistic pathogens, there was no correlation between the isolates in this study and the surveillance report of nosocomial infection during the period of study, hence the contribution of the indoor air cannot be established. From the reduction noticed in the morning samples, stringent measures such as proper disinfection and regular cleaning, restriction of patient relatives' movement in and out of the wards/units need to be enforced so as to improve the quality of indoor air of our hospital wards/units.

Field study of thermal comfort and indoor air quality in gymnasium

To analyze the thermal comfort and indoor air quality (IAQ) in a medium-sized mechanically ventilated gymnasium in Beijing,a field study was carried out. PHOENICS,one of the CFD software,was chosen to simulate the distribution of the indicators of indoor air in the gymnasium to check the air-conditioning parameters reasonable or not. And there was a questionnaire for audiences and staff about the acceptance and satisfaction of the thermal comfort,simultaneously,some environmental parameters were monitored. Then an experiment was carried out in gymnasium with the plate sedimentation to the biological aerosol in the air. Finally,the thermal comfort and IAQ in the gymnasium were assessed based on the results of above questionnaire survey and measurements. The results show that most parameters of the environmental are within the standard limits of thermal comfort and IAQ in the monitored period,and the biological contaminants initially come from human beings. The main species in the gymnasium are streptobacillus,coccus,cladosporium,penicillium and neurospora.

STUDY ON HUMAN EXPOSURE ASSESSMENT TO INDOOR/OUTDOOR AIR POLLUTANTS

实验设计了人群活动与室内污染状况调查，其内容包括：被调查者家庭生活环境、家庭成员个人活动、个人嗜好；工作环境情况及被调查者本人的生活、工作和活动环境对健康影响的主观评价等．结果表明，城市居民一天在室内环境度过的时间约占全天时间的８４％以上．同时参考国内外室内／外空气污染研究结果，选取４种主要空气污染物——一氧化碳（ＣＯ）、甲醛（ＨＣＨＯ）、可吸入性颗粒物（ＩＲ）和苯并［ａ］芘（Ｂａｐ）等进行了现场测定．给出不同微环境，即家庭室内环境，非家庭室内环境、封闭交通工具内、室外交通环境、其它室外环境中４种典型污染物的人体暴露量估计值．实验表明，４种空气污染物在家庭室内环境中的人体暴露量分别为：７１．０％，６０．３％，６９．４％，７４．０％．由此可以看出，在大气污染对人体健康影响的研究中，室内环境的影响不容忽视．

Recommended Concentration Limits of Typical Indoor Air Contaminants

From the view of both objective and subjective factors,the indoor air quality(IAQ)evaluation was considered.Carbon dioxide(CO2)and formaldehyde(HCHO)were selected as the typical contaminants of indoor air,and the evaluation method of logarithmic index was adopted as the evaluation means of IAQ.Then the recommended limits(RL)of typical contaminants CO2 and HCHO were given through analysis and calculation.The limits of CO2 and HCHO in Indoor Air Quality Standard of China or other existing standards probably correspond to the level of PD=25(%).The result shows that the existing standards fail to meet the requirement of the definition of "acceptable indoor air quality",that is to say,less than 20% of the people express dissatisfaction.When PD=20%,RL of CO2 and HCHO are 728×10-6 and 0.068×10-6 respectively,which are stricter than the limits in the existing standards.The method proposed in this paper is applicable to 13.1%≤PD≤86.7%.

Liquid-like adsorbent assembled by CNTs: Serving as renewable CO_(2) capture materials for indoor air

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.

Effectiveness of Improved Cookstoves to Reduce Indoor Air Pollution in Developing Countries. The Case of the Cassamance Natural Subregion, Western Africa

The Spanish NGO “Alianza por la Solidaridad” has installed improved cookstoves in 3000 households during 2012 and 2013 to improve energy efficiency reducing fuelwood consumption and to improve indoor air quality. The type of cookstoves were Noflaye Jeeg and Noflaye Jaboot and were installed in the Cassamance Natural Subregion covering part of Senegal, The Gambia and Guinea-Bissau. The Technical University of Madrid (UPM) has conducted a field study on a sample of these households to assess the effect of improved cookstoves on kitchen air quality. Measurements of carbon monoxide (CO) and fine particle matter (PM2.5) were taken for 24-hr period before and after the installation of improved cookstoves. The 24-hr mean CO concentrations were lower than the World Health Organization (WHO) guidelines for Guinea-Bissau but higher for Senegal and Gambia, even after the installation of improved cookstoves. As for PM2.5 concentrations, 24-hr mean were always higher than these guidelines. However, improved cookstoves produced significant reductions on 24-hr mean CO and PM2.5 concentrations in Senegal and for mean and maximum PM2.5 concentration on Gambia. Although this variability needs to be explained by further research to determine which other factors could affect indoor air pollution, the study provided a better understanding of the problem and envisaged alternatives to be implemented in future phases of the NGO project.

Questionnaire Research on Indoor Environment Quality i n China

With 1 185 pi eces of questionnaire, it is found that in China, people take fresh air, odor, e tc., as well as indoor air temperature, humidity, as the most important indoor a ir parameters. It is also found that there is a significant sensitivity differen ce in indoor environment between southerners and northerners in China. People fr om different regions have different demands for their working and living environ ment. Therefore, as a good design of air conditioning system, it is strongly rec ommended that the different demands of people from different regions should be t aken into consideration.

An extended analysis of cardiovascular benefits of indoor air filtration intervention among elderly:a randomized crossover trial(Beijing indoor air purifier study,BIAPSY)

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.

Dynamic characteristics and comfort assessment of airflows in indoor environments： A review

During the past few decades, both positive and negative aspects of indoor air movement on human comfort perception have been studied. However, most research has focused on collecting empirical evidence to support the potential application of airflows in practice. In this context, numerous studies have encouraged the use of moving air to promote comfort in warm environments, especially with regard to the application of dynamic airflows. Through these studies, the effects of different airflow parameters(such as air velocity, turbulence intensity, and fluctuation frequency) on human comfort perception have gradually been identified and even quantified. This article aims to summarize the progress in the literature concerning dynamic characteristics and comfort assessment of airflows in four main sections: demand for indoor airflows, parameters of indoor airflows, comfort assessment of indoor airflows, and dynamic airflows and their application.This paper will hopefully aid the understanding of human perception of indoor airflows and guide future research.

Sedimentation behavior of indoor airborne microparticles

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 in- tervals (1 d, 3 d, 10 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 sedi- ment 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.

Research on indoor air pollution of newly decorated buildings in Chongqing

The investigation of indoor-air quality in newly built and newly decorated residences in Chongqing revealed that the average concentration of formaldehyde and ammonia in these residences exceeded the upper limits of the standard. The situation of indoor air pollution varied with the type of rooms. The results of investigation show that the indoor-air pollutants caused by decoration work should not be ignored anymore.