Concentrations Of Indoor Air Pollutants Research Articles

Accumulation and Diffusion of PM from Outdoor to Indoor by Clothing under Haze Conditions: A Case Study of Zhengzhou, China

Clothing can absorb fine particulate pollutants from the atmosphere outdoors and then release them after entering the room in a form similar to three-handed smoke. In this study, the experimental site in Zhengzhou, a typical city with heavy pollution in central China, was used to investigate the adsorption and diffusion patterns of three different fabrics of polyester, polyester-cotton, and cotton clothing for fine particle pollutants, to guide people’s behavior patterns and indoor air distribution, and to reduce indoor pollution exposure. The results showed that when garments of three different fabrics were exposed to moderate and heavy PM2.5 pollution for 1 h, 2 h, and 3 h, respectively, and then transferred to the diffusion chamber, polyester always released the highest PM2.5 concentration to indoor air during the same release cycle, followed by cotton and polyester-cotton. In addition, the concentration of indoor air pollutants will be periodically affected by the diffusion of fine particulate adsorbed by clothing fabrics. With the increase in outdoor pollution and exposure duration, the indoor PM2.5 concentration takes longer to stabilize at certain levels after the clothing is transferred to the indoor side. Finally, the comparison of natural ventilation experiments proved that it is not feasible to rely solely on natural ventilation to improve the influence of clothing pollution sources on indoor air quality.

Development of ASTM International D8405—Standard Test Method for Evaluating PM2.5 Sensors or Sensor Systems Used in Indoor Applications

Sensors and sensor systems for monitoring fine particles with aerodynamic diameters smaller than 2.5 µm can provide real-time feedback on indoor air quality and thus can help guide actions to manage indoor air pollutant concentrations. Standardized verification of the performance and accuracy of sensors and sensor systems is crucial for predicting the efficacy of such monitoring. A new ASTM International standard test method (ASTM D8405) was created for this need and is the most exacting laboratory protocol published to date for evaluating indoor air quality sensors and sensor systems measuring particles smaller than 2.5 µm in diameter. ASTM D8405 subjects sensors and sensor systems to five test phases: (1) an initial particle concentration ramp; (2) exposure to various temperature and humidity conditions; (3) exposure to interfering particles; (4) temperature cycling; and (5) a final particle concentration ramp to assess drift. This paper discusses the development of the standard test method, key aspects of the testing process, example evaluation results, and a comparison of this standard test method against peer evaluation protocols.

The Changes in Indoor Air Pollutant Concentration in Nursery in Dubai, United Arab Emirates

Recent statistics indicate that as indoor pollutants' effects on the human body become a severe issue in Dubai, the need for systematic IAQ (indoor air quality) management is increasing. This paper aims to identify the IAQ pollution status according to the characteristics of nursery rooms and playrooms and suggest ventilation methods. As a methodology, indoor temperature and humidity and indoor air pollutants (Carbon Dioxide (CO2), PM10, Formaldehyde (CH2O), TVOC (Total volatile organic compounds) were measured in two different scales nurseries. The result showed that CO2 was measured below the maintenance standards of KHDA regulation at all measurement points, nursery A at 870 ppm and nursery B at 860 ppm. PM10 has exceeded the maintenance standard of 100 μg/m3 in the playroom and nursery room of nursery A due to less cleaning times and ventilation. TVOC was 1,504 μg/m3 and 723 μg/m3 in both facilities, exceeding the recommended standard of 400 μg/m3 in the nursery room. CH2O concentration was below the maintenance standard at all measurement sites. This study will serve as primary data for further investigation of indoor air pollution in nurseries according to the size and type.

Optimisation of Building Green Performances Using Vertical Greening Systems: A Case Study in Changzhou, China

The benefits of greening systems on buildings have been frequently examined using experimental methods. However, few studies have adopted dynamic monitoring of real operational buildings to quantify the effects of greening systems on multiple building green performance indexes, such as thermal comfort, indoor air quality, and energy consumption. In this study, a type of multi-in-one indoor environmental quality monitoring device was adopted for vertical greening systems in a green-certified building in Changzhou, China, with real-time data collection through an Internet of Things platform. Measurements of the indoor thermal environment and air quality were recorded from four testing points during a 90 day period from spring to summer in 2021. For comparison, the testing points were divided into group A (office zone) and group B (exhibition zone). Our results demonstrated that, in the presence of a vertical greening system, the seasonal average indoor temperatures decreased by up to 0.7 °C. The green facade outperformed the ordinary exterior wall, optimising both indoor thermal comfort and thermal inertia. Furthermore, judicious indoor greening designs significantly reduced the indoor air-pollutant concentrations, such as particulate matter, carbon dioxide, and organic pollutants. The median values for particulate matter 10 and formaldehyde concentration decreased by 20.7% and 33.3%, respectively, thus improving the indoor air quality. Lastly, the annual electricity consumption of the building with vertical greening systems was about 25% lower than that of similar buildings, underlining the potential contribution of vertical greening systems to building energy conservation. Such findings collectively demonstrate that greening systems offer quantifiable benefits for building parameters such as thermal properties, indoor air quality, and energy conservation.

Indoor Air Quality and Microclimatic conditions in selected Restaurants and Kitchens at a Tertiary Institution in Benin City, Nigeria

This study investigated the levels of selected indoor air pollutant concentrations and microclimatic conditions in restaurants and kitchens at a tertiary institution in Benin City using standard procedures. Ten (10) restaurants and kitchens were randomly selected within the University environment. Indoor particulates (PM1.0, PM2.5 and PM10), Carbon monoxide (CO), Relative humidity (RH), Temperature (Temp) and Wind speed (WS) were measured using Handheld Portable Air Samplers. The results showed that the indoor meteorological and air quality parameters ranged between 34.8 - 35.8°C and 34.5 - 35.9°C (Temp); 42.8 -70.2% and 39.7 - 66.9 (RH); 1.1 - 2.0 m/s and 1.2 - 1.8 m/s (WS); 0.0 - 25.4 and 0.0 - 28.7 mg/m3 (CO); 28.9 - 42.4 µg/m3 and 24.4 µg/m3 - 30.6 (PM1.0); 47.0 - 75. µg/m3 and 37.4 - 50.3 µg/m3 (PM2.5); 62.3 - 91.0 µg/m3 and 53.6 - 56.8 µg/m3 (PM10) within the restaurants and kitchens respectively. The mean concentrations of the CO and particulates were above the recommended regulatory limits of the WHO in all sampling sites. There were generally weak significant associations between the observed meteorological parameters and the indoor air pollutants (R= -0.352, - 0.419 p<0.001), except for CO and indoor temperature in the kitchens (R=0.649, R2 = 0.429 p<0.001). The Air Quality Index (AQI) status of the sampled sites varied from moderate to unhealthy. This study underscores the need for adequate ventilation in the sampled restaurants and kitchens and the creation of awareness of the health risks associated with indoor air pollutants in the study area.

The aerobiome in a hospital environment: Characterization, seasonal tendencies and the effect of window opening ventilation

The urban atmosphere carries biological particles (bioaerosols) that may cause several diseases and allergies. These bioaerosols infiltrate and mix with those present inside the buildings, including hospitals. However, little is known about the behavior of these particles around health facilities. Here, we described the bioaerosols composition of an urban hospital indoor and outdoor at two different periods (winter and summer) using DNA sequencing. We observed that the seasonality and composition of the bioaerosols outdoor was also displayed indoor, and, in some cases, the taxa showed different trends depending on the season. Pathogenic species of bacteria and fungi were found indoors at low levels but also outdoors, being mostly environmental species, which would reject the idea that hospitals may be acting as a source of emission via aerosols. Skin-related bacteria were the most prevalent group related to human microbiome, being more abundant indoors. Air temperature was the principal factor affecting the bioaerosols composition in the samples but, in general, meteorological parameters outdoors were poor descriptors of the bioaerosols indoors. Similarly, the concentrations of the main indoor air pollutants did not correlate with microbial abundances. Globally, natural ventilation through a window opening did not significantly alter the composition of the bioaerosols indoor.

Impact of Improved Cookstoves on the Level of Household Exposure to CO and PM<sub>2.5</sub> in Sub-Saharan Cities: The Case of the City of Ouagadougou

Air pollution is one of the major global threats to human health. In Burkina Faso, more than 80% of the population uses solid fuels as the main source of cooking energy. This paper reports a comparative study on the exposure of household to the carbon monoxide (CO) and particulate matter (PM2.5) emitted by improved cookstoves (ICS) or traditional cookstoves (TCS). A cross-sectional study was conducted in the city of Ouagadougou for 4 months during the rainy season (July to October) in households with an outdoor kitchen. The investigation involved 92 households where air pollutants, such as PM2.5 and CO were measured with Indoor Air Pollution Meters (IAP meter). These measurements were focused on the concentration levels of the pollutants during cooking. The results of this study show high levels of PM2.5 and CO for all type of stoves. Wood stoves led to higher PM2.5 and lower CO emissions than charcoal stoves. ICS reduce emissions of indoor air pollutants compared to TCS. This reduction raised up to 82% for PM2.5 and 37% for CO. The analysis of the data measured with the student test (t-test) shows that there is a statistically significant difference between the average values of the concentrations of the pollutants emitted with the TCS compared to ICS, except for CO emissions measured on multi-pot sizes cookstoves (MM). This study shows that the concentrations of indoor air pollutants are very high regardless of the type of cookstoves used. The CO exposure obtained varies from 119.10 to 362.72 μg/m3 for 15-minute and 10.83 - 55.11 μg/m3 for 1-hour exposure. The exposure in PM2.5 varies from 4762 to 16,257 μg/m3 for 15-minute and 106.63 to 1597 μg/m3 for 1-hour of exposure. It was noted that the CO exposure levels obtained over 15-minute of exposure are 1.36 to 4.15 times higher than the WHO recommendation and 1.8 times higher for an exposure time of one hour. This means that women in charge of cooking have a high risk of exposure to air pollutants.

青藏高原牧区家庭能源消费对生态环境和人体健康的影响研究现状与展望

PDF HTML阅读 XML下载 导出引用 引用提醒 青藏高原牧区家庭能源消费对生态环境和人体健康的影响研究现状与展望 DOI: 10.5846/stxb202202190395 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（72174197，41901241，71904189）；第二次青藏高原综合科学考察研究项目（2019QZKK0304） Research status and prospect of household energy consumption impact on eco-environment and human health in the pastoral of Qinghai-Tibet Plateau Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:探究家庭能源消费对生态环境和人体健康的研究是系统推进家庭能源绿色低碳转型和实现联合国2030可持续发展目标的关键。重点综述了目前家庭能源消费、影响因素及其对生态环境和居民健康影响的国际研究现状。目前研究不足主要聚焦在以下两个方面：一方面，影响家庭能源消费因素的贡献率和影响消费行为的驱动机制尚不清晰；另一方面，目前主要针对家庭能源消费或者生态系统或者环境或者居民健康其中的某一方面或者某两个方面开展研究，鲜有研究系统的考虑家庭能源消费对生态环境和人体健康影响的综合研究。基于上述研究现状，结合青藏高原的实际情况，提出未来需要在宏观层面和微观层面加强研究。宏观层面：（1）亟需厘清青藏高原家庭能源与生态环境和人体健康之间的内在联系与驱动机制，形成青藏高原牧区"家庭能源-生态效应-环境效应-健康效应"的理论分析框架；（2）构建模块化的牧区"能源-生态-环境-健康-经济"等多学科交叉的综合评估模型，形成完整的、系统的评估方法。微观层面：（1）迫切开展青藏高原家庭能源消费特征与变化规律的研究；（2）深入开展家庭能源消费特征和变化规律与生态系统的反馈机制与量化研究；（3）加强牧区室内空气污染物浓度测定，丰富高寒地区室内污染物浓度数据以及人群暴露特征及其健康风险的研究。 Abstract:Exploring the household energy consumption and its impacts on eco-environment and human health is essential to promote the green and low-carbon transition of household energy system and achieve the 2030 United Nations Sustainable Development Goals. This paper presents a review on the state of the art for the domestic and international research on the factors that influencing the household energy consumptions and the impacts on eco-environment and residents' health. At present, particular attention should be given to the following two research deficiencies. On one hand, the contribution rate of factors that influencing the household energy consumption and the mechanism that driving the consumption behavior are not well understood; on the other hand, the comprehensive studies that systematically consider the correlations among household energy consumption, ecological environment and human health are still lacking. Based on the research status and the actual situation of Qinghai-Tibet Plateau, this paper strengthens the study of household energy consumption and its impact on eco-environment and human health through macro level and micro level. On the macro level, we need to (1) clarify the correlation and driving mechanism between household energy, grassland ecology and human health and form the theoretical framework for analysis in the pastoral region of Qinghai-Tibet Plateau; (2) build a comprehensive modular assessment method around the energy-ecology-environment-health-economy nexus. On the micro -level, we should (1) carry out the research on the characteristics and dynamics changes of household energy consumption on the Qinghai-Tibet Plateau; (2) establish and quantify the feedback mechanism between household energy consumption and ecosystem; (3) strengthen the measurement of indoor air pollutant concentration in the pastoral areas and complete the data collection on the exposure characteristics and the associated health risks for the residents living in the alpine areas. 参考文献 相似文献 引证文献

A Study on the Distribution Characteristics of Formaldehyde, Volatile Organic Compounds, Particulate Matter, and Airborne Bacteria in Indoor Play Centers

This study aimed to evaluate the indoor air quality differences at 19 indoor play centers of cafés and play areas in Gyeonggi-do where were 430 m<sup>2</sup> or larger. We examined concentrations of formaldehyde (HCHO), volatile organic compounds (VOC), particulate matter, and total airborne bacteria, and how their distributions varied with the number of visitors at the places. On weekdays, there were no statistically significant differences in mean indoor air pollutant concentrations between the cafés and play areas at 95% confidence intervals. However, significant differences were observed on weekends when the number of visitors increased. HCHO concentrations increased up to 159%, and VOC concentrations increased up to 210%. A higher increase rate of HCHO occurred at the cafés compared to the play areas since cooking operations were performed under natural ventilation. The PM10 concentration increased by approximately 33.2%, with an increase of 49.2% in the play areas and a 18.3% increase in the cafés on weekends. PM<sub>2.5</sub> concentration particularly increased during weekends in the cafés and play areas by 113% and 63.6%, respectively. During cooking operations, the concentration of gaseous and particulate pollution increased more in the air pollutant concentration of cafés, and the overall bacterial concentration increased during weekends due to higher numbers of visitors. Therefore, indoor play centers with cooking operations require adequate air quality management to mitigate the indoor pollution.

A longitudinal study on the effects of hygro-thermal conditions and indoor air pollutants on building-related symptoms in office buildings.

We conducted a longitudinal epidemiological study for over 1year in Tokyo and Osaka, Japan, beginning June 2015, to examine the association between indoor environmental factors and building-related symptoms (BRSs) in office workers. Data were obtained from 483 subjects (225 females and 258 males) in 24 office rooms in 11 office buildings. Environmental monitoring was conducted for hygro-thermal conditions and carbon dioxide and sampling was performed for indoor air pollutants. Questionnaires were concurrently administered to collect information on participants' perceptions of their comfort and health and the conditions of the work environments. Multivariable analyses revealed that upper respiratory symptoms were significantly correlated with a decrease in both relative [odds ratio (OR): 0.77; 95% confidence intervals (CI): 0.62-0.95; p=0.014] and absolute humidity (OR: 0.89; 95% CI: 0.81-0.97; p=0.008). Statistically, significant evidence was found that average relative humidity of <38% (OR: 2.68; 95% CI: 1.36-5.27; p=0.004) showed the most significant association with increased risk of upper respiratory symptoms. Air concentrations of carbon dioxide showed no significant correlation with BRSs at mean concentrations <1000 ppm in most buildings surveyed. Most indoor air pollutant concentrations were relatively low or lower than the values set by indoor air quality guidelines and the values of thresholds for sensory irritation. Air concentrations of indoor air pollutants showed no significant correlation with BRSs. Our data emphasize the importance of appropriate humidity control during low humidity in winter.

Gaseous Air Pollutants and Respirable Crystalline Silica Inside and Outside Homes at Brick Kilns in Bhaktapur, Kathmandu Valley, Nepal.

Household and ambient air pollution remain public health problems in much of the world. Brick kiln employees in Nepal may be particularly at risk of high air pollution exposures and resulting health effects due to high levels of outdoor air pollution, substandard housing, and indoor biomass cooking. We conducted a cross-sectional study of indoor and outdoor air pollution concentrations at workers’ homes at four fixed chimney Bull’s trench brick kilns in Bhaktapur, Kathmandu Valley, Nepal. We measured air concentrations of carbon monoxide (CO), carbon dioxide (CO2), nitrogen dioxide (NO2), sulfur dioxide (SO2), and respirable crystalline silica (SiO2; cristobalite, quartz, tridymite) using established methods and conducted a survey about characteristics of homes or samples that may be associated with air pollution concentrations. Geometric mean concentrations of CO, CO2, and SiO2 (quartz) were 0.84 ppm, 1447.34 ppm, and 6.22 µg/m3, respectively, whereas concentrations of all other air pollutants measured below lower detection limits. Most characteristics of homes or samples were not associated with air pollution concentrations. We found a positive association between the variable how long lived in house and SiO2 (quartz) concentrations, which may reflect sustained take-home exposure to SiO2 (quartz) over time. Interventions should focus on administrative controls to reduce take-home exposure to SiO2 (quartz) in this population.

Identifying the relationship between VOCs emission and temperature/humidity changes in new apartments in the hot desert climate

Much previous research in different countries describes a strong dependence on temperature and humidity for indoor air pollutants generated from building materials. Since many types of building materials are complexly applied in residential buildings in UAE and are constantly using air-conditioning, the result might be different from the characteristics of indoor air pollutants from a small chamber experiment. This paper aims to investigate the relationship between the concentration of indoor air pollutants according to changes in temperature and humidity in newly built apartments before moving in. As a methodology, a field measurement was performed in 23 housing units in five different residential towers in Ajman, United Arab Emirates. Before the measurement, a 7-day bake-out was completed, and the target units were measured 30 days before moving in. The result showed that formaldehyde (HCHO) and VOCs such as benzene (C6H6), toluene (C7H8), ethylbenzene (C8H10), xylene (C8H10), and styrene (C8H8) have consistent humidity dependence within the range of 15 %–60% of relative humidity (RH). It was impossible to confirm the temperature dependency since it showed different characteristics for each apartment between 22°C and 33°C. There is a limit to predicting the occurrence of indoor air pollutants in the apartment only with microclimatic factors since there are many other variables, such as various building materials, management history of materials, and construction methods. However, it was proven that there is an emission cut-off point where the generation of indoor air pollutants deviates from a linear relationship in the RH 40%–50% and 25°C. These temperature and humidity ranges are synchronized with daily life ranges.

Optimization of ventilation performance of side air supply for large indoor spaces using deflectors and slot air outlets

Due to the large height and span of indoor spaces, efficient indoor ventilation performance may be difficult to achieve using the side air supply for large halls, to control the indoor air pollutants or reduce the infection risk, such as the transmission of COVID-19 within the breathing zone of occupants. An efficient Ventilation Mode with Deflector and Slot air outlets (VMDS) was developed by this study. The use of a deflector with slot air outlets was introduced by utilizing jet collision and adhesion effect to accentuate the ventilation performance of the side air supply for the large space. The numerical simulation model used in this study was validated experimentally. The VMDS was compared with three other side air supply modes used in large spaces, and the results were evaluated comprehensively. The results show that VMDS is effective in reducing indoor air pollutant concentrations and transmission of infectious diseases in large spaces while satisfying the energy efficiency and thermal comfort requirements. Compared with the common side-supply and side-return ventilation modes, VMDS can reduce indoor air pollutant concentration by nearly 40%, reduce the transmission risk of infectious disease to less than 1% at a low air change rate and increase the ventilation efficiency from about 0.85 to about 1.2. In addition, VMDS can theoretically reduce ventilation energy consumption by about 85%.

Indoor Air Pollution in Rumuewhera Community in Obio-Akpor Local Government Area of Rivers State, Nigeria

Indoor air pollution arising from the use of biomass fuel for cooking is a serious health issue in Nigeria especially in rural communities. This study investigated the levels of Carbon monoxide (CO), PM2.5 and PM10 released during morning and evening cooking sessions in 17 households in Rumuewhara community in Obio/Akpor LGA, Rivers State Nigeria. This was to ascertain indoor air pollution concentrations in rural households categorized in the terms of fuel type (Firewood, Kerosene and LPG) and kitchen configuration. In the morning cooking session, mean and standard deviation of CO, PM2.5 and PM10 concentration levels from households using LPG (8.78 + 5.20 ppm, 25.5 + 6.65 µg/m3 and 39.38 + 13.28 µg/m3) were observed as lower than those from other households using biomass fuels (36.78 + 19.44 ppm, 270.16 + 159.44 µg/m3 and 419.82 + 247.29 µg/m3 for firewood). The mean concentrations of CO, PM2.5 and PM10 during cooking sessions in firewood kitchens are clearly higher than the standard limits of WHO and Health Canada due to the fuel type, kitchen configuration and ventilation habit. With correlation coefficients, r = -0.537, P=.03; r = -0.583, P=.01 and r = -0.566, p=0.02; there is a statistically significant and strong negative correlation between Relative Humidity vs CO, PM2.5 and PM10 respectively. The use of biomass fuels for household cooking should be discouraged in favour of LPG or kerosene due to the high concentration of indoor air pollutants it generates. To reduce the effects of biomass fuels, well-positioned Chimneys should be incorporated into houses to limit the accumulation of indoor air pollutants in the cooking area.

Development of a back-propagation neural network combined with an adaptive multi-objective particle swarm optimizer algorithm for predicting and optimizing indoor CO2 and PM2.5 concentrations

People now spend between 80% and 90% of their lifetimes in indoor locations such as offices and residential buildings. These extended hours indoors have substantial health impacts, making it vital that people have adequate indoor air quality (IAQ). The management of IAQ presents two issues: (1) rapidly predicting and controlling IAQ using current intelligent ventilation systems is difficult, and (2) simultaneously controlling both gas pollutants (of which CO2 is a representative example) and particulate matter concentrations (for example, PM2.5) while achieving optimal outcomes is challenging. Therefore, this study aims to develop a fast and accurate optimization algorithm to simultaneously predict and control indoor CO2 and PM2.5 concentrations. To this end, a back-propagation neural network (BPNN) combined with an adaptive multi-objective particle swarm optimizer (AMOPSO) algorithm based on computational fluid dynamics (CFD) is proposed. The CFD model first creates a database of indoor CO2 and PM2.5 concentrations. Then, based on the CFD database, the BPNN model is used to predict indoor air pollutant concentrations. If the predicted concentrations do not meet predetermined limits, the AMOPSO algorithm is initialized to optimize the concentrations of the indoor air pollutants. In test examples, the proposed optimization algorithm reduces CO2 concentrations by up to 30.5%, while also reducing PM2.5 concentrations by as much as 77.1%.

Indoor Air Quality Forecast in Shared Spaces

The high concentration of air pollutants in indoor environments can have a remarkable adverse impact on health and well-being, cognitive performance and productivity. Indoor air pollutants are especially problematic in naturally ventilated shared spaces such as classrooms and meeting rooms, where human-generated pollutants can rise rapidly. When the inhabitants are exposed to indoor air pollution, recovering from its ramifications takes time and harms their well-being in the long run. In our approach, we seek to predict and prevent such hazardous situations instead of rectifying them after they happen. The prediction and prevention are accomplished through algorithms that can learn from the evolution of air pollutants and other variables to indicate whether or not a high level of pollution is forecast. We present two AI-enabled methods, one providing the forecast for the concentration level of carbon dioxide in the next 5 and 20 minutes with 86% and 92% accuracy. The second algorithm provides predictive indicators about how the CO2 level will evolve during the upcoming session (meeting or a course) before the session starts. We will discuss design implications and present design proposals on how these methods can inform interactive solutions for preventing high concentrations of indoor air pollutants.

Investigations of indoor air quality for office buildings in different climate zones of China by subjective survey and field measurement

This study investigated the indoor air environment of office buildings in different climate zones of China, including the indoor air pollutant concentrations, and its associated interactions with the staffs' feelings and health symptoms, which could provide basis to improve the indoor environments of office buildings. Thermal parameters and pollutant (including CO2, formaldehyde and TVOC) concentrations were monitored in different floors of sampled office buildings. Questionnaire were also surveyed to investigate humans' perception to the indoor air quality and the associated sick building syndrome. Furthermore, cancer risk assessments of these office buildings were carried out based on onsite air pollutants data. The results showed that indoor and outdoor pollutant concentrations are highly correlated, and the pollutants concentration levels vary over the time of the day, with poor indoor conditions observed in the morning and the afternoon. The questionnaire results suggested that actions should be taken to improve the indoor air environment of office buildings, and ventilation appears to be the most desirable strategy. The risk assessment results showed that health problems could exist even though the pollutant concentration levels in the indoor environment were within the standard limits. This paper investigated the discomfort reasons in the office buildings by providing pollutant concentrations and health risk assessment data together with information about the human's perception on the indoor environment. Finally, we noted that outdoor fresh air with purifiers/filters should be used to reduce the indoor pollutant concentrations.

User behavior, influence factors, and impacts on real-world pollutant emissions from the household heating stoves in rural China

Household heating stoves are commonly used for heating in rural China during winter and are responsible for a large portion of the particulate matter in the atmosphere. Pollutant emissions from household stoves are influenced by user behaviors in actual use, in addition to purely technological reasons (i.e., type and age of appliance) and installation conditions (i.e., the natural draft of chimney system). The variability in user behavior is one of the reasons for uncertainty in household emission inventories. In this study, household stove user behaviors, including ignition frequency, heating with or without cooking, smoldering duration, and fuel-adding times, were investigated through face-to-face surveys in Shanxi province, north China. The survey of user behaviors showed that the majority of the RHS users (81.3%) and approximately half of the WHS users (49.4%) used their stoves for both cooking and heating, whereas the remaining users used their stoves just for heating. Approximately 80% of surveyed households (97.4% for water heating stove and 68.7% for radiant heating stove) kept the stoves smoldering at night, whereas the remaining users ignited their stoves every day. The highest frequency of smoldering duration and highest frequency of fuel-adding operation were 8–9 h and 4–7 times, respectively. Principal component analysis showed that stove type, permanent population, and annual income are the potential influencing factors of user behavior. The smoldering duration was positively related to indoor air pollutant concentrations and fuel-adding times had a significant impact on outdoor PM2.5 emission factors. The results from this research will be beneficial for understanding the cause of fluctuation in emissions and designing heating appliances for real-life operations.

A coupled computational fluid dynamics and back-propagation neural network-based particle swarm optimizer algorithm for predicting and optimizing indoor air quality

In the modern era, people spend approximately 90% of their time in indoor settings, such as offices and residential buildings. As prolonged exposure to indoor environments can significantly impact health outcomes, it is important to ensure that good indoor air quality (IAQ) is achieved. The main obstacles to achieving effective control of IAQ are twofold. First, it is very difficult to monitor the values of IAQ parameters, especially within a person's breathing zone. Second, current heating ventilation and air conditioning systems are unable to rapidly predict and optimize IAQ. This study aims to obtain accurate indoor environmental parameters for rapidly predicting and optimizing IAQ. To achieve this, a computational fluid dynamics (CFD)-based back propagation neural network (BPNN) combined with a particle swarm optimizer (PSO) algorithm is proposed. Notably, the BPNN-PSO algorithm can rapidly predict and optimize IAQ while using a limited number of CFD runs. In comparison with other state-of-the-art methods for controlling IAQ, such as the artificial neural network (ANN)-genetic algorithm (GA), the BPNN-PSO algorithm further reduces the concentration of indoor air pollutants by up to 6.44% and computational costs by as much as 23.53%. The use of CFD ensures that the information obtained is accurate and allows for rapid prediction of indoor environmental conditions. The BPNN-PSO algorithm has the potential to contribute very effective and intelligent control strategies for ventilating indoor environments.

COVID-19 pandemic in Uttarakhand, India: Environmental recovery or degradation?

The human coronavirus disease-2019 (COVID-19) caused by SARS-CoV-2 is now a global pandemic. Personal hygiene such as hand-washing, the use of personal protective equipment, and social distancing via local and national lockdowns are used to reduce the risk of transmission of SARS-CoV-2. COVID-19 and the associated lockdowns may have significant impacts on environmental quality and ergonomics. However, limited studies exists on the impacts of COVID-19 and the associated lockdowns on environmental quality and ergonomics in low-income settings. Therefore, the present study investigated the impacts of the COVID-19 outbreak on socioeconomics, ergonomics and environment (water quality, air quality and noise) in Uttarakhand, India. Approximately 55% of respondents experienced headaches, and the other common health-related issue was back pain, with 45% of respondents having problems with their backs. Water and air quality significantly improved during the lockdown relative to the pre-lockdown period, but was observed to return to their previous characteristics afterwards. Lockdowns significant increased the concentration of indoor air pollutants while noise pollution levels significantly declined. In summary, lockdowns have adverse impacts on ergonomics, resulting in work-related human health risks. The impacts of lockdowns on environmental quality are mixed: temporary improvements on water and air quality, and noise reduction were observed, but indoor air quality deteriorated. Therefore, during lockdowns there is a need to minimize the adverse environmental and ergonomic impacts of lockdowns while simultaneously enhancing the beneficial impacts.