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Most studies on Chinese dormitories are carried out in summer, while few focus on a transition season or winter. This study evaluated the air quality of a student dormitory in a university in the Beijing area by using a questionnaire survey and on-site measurements. The CO2 concentration was used as an indoor air quality evaluation index to characterize the freshness of the air, and different window opening conditions in the dormitory were simulated, with corresponding improvement plans proposed. The results of this study revealed that the air quality and thermal comfort of the student dormitories during a transition season and winter fell short of expectations. According to the survey, students who opened their windows frequently had a better subjective perception of the air quality. However, due to the large temperature difference between day and night, more than 80% of the students felt too cold when opening the windows. For daytime conditions, the area of unilateral ventilation window opening should not be less than 0.39 m2, the area of bilateral ventilation window opening should not be less than 0.13 m2, and the time taken to close the windows and doors should not exceed the maximum ventilation interval. Empirical equations were fitted for nighttime conditions based on the CO2 concentration, number of people in the room, and window opening area, resulting in a reasonable window opening area of 0.349 m2~0.457 m2. In sum, this study assessed the air quality status within typical university dormitories across varying seasons, gaining a clear understanding of how different ventilation strategies and occupant densities influence air freshness and thermal comfort. Based on these insights, a practical and optimized window area recommendation was formulated to enhance the indoor environmental quality in these dormitories. [ABSTRACT FROM AUTHOR]

The air quality in classrooms significantly impacts school children's health and learning performance. It has been reported worldwide that classroom air quality does not meet the required standard and actions are pledged for improvement. However, it poses a challenge for decision-making in terms of prioritising taking-up measures. The aim of this study is to propose a method of identifying the action measures for improving classroom air quality and prioritising them. Case studies in the UK and China were conducted, and the key measures were identified through literature studies, open-ended questionnaire surveys, and workshop discussions, which are classified into three categories: B1, policy; B2, technology; and B3, information sharing. The analytical hierarchy process (AHP) is applied in the prioritisation of the action measures. A total of 138 teachers and parents from China and the UK participated in this case study. The genetic algorithm-optimised Hadamard product (GAOHP) method is applied to justify the consistency ratio (CR) within the required threshold value in order to ensure the consistency of the subjective perception and the accuracy of comparative weights. The results show that item B2, technology, is the most desired measure by both Chinese and British parents and teachers, despite the deviation from the optimal choice in China and the UK. Among the proposed action measures, the UK respondents strongly expected air purifiers with natural ventilation as opposed to their Chinese counterparts preferring to share the real-time status of classroom air quality. Our work will provide strong support for the subsequent selection of indoor air quality improvement strategies for schools. [ABSTRACT FROM AUTHOR]

Building fresh air supply needs to meet certain regulations and fit people's ever-growing indoor air quality demand. However, fresh air handling requires huge energy consumption that goes against the goal of net-zero energy buildings. Thus, in this work, an adaptive fresh air pre-handling system is designed to reduce the cooling and heating loads of HVAC system. The sky-facing surface of the system uses electrochromic mechanism to manipulate the optical properties and thus make full use of solar energy (solar heating) and deep space cold source (radiative cooling) by switching between heating and cooling modes. In the cooling mode, the sky-facing surface shows a transmittance of down to zero, while the reflectance is high at 0.89 on average. In the heating mode, the electrochromic glass is highly transparent, allowing the sunlight to reach the solar heat absorber. To obtain the energy-saving potential under different climates, six cities were selected from various climate regions in China. Results show that the adaptive fresh air pre-handling system can be effective in up to 55.4% time of a year. The maximum energy-saving ratios for medium office, warehouse, and single-family house can reach up to 11.52%, 26.62%, and 18.29%, respectively. In addition, the system shows multi-climate adaptability and broad application scenarios, making it a potential solution to building energy saving. [ABSTRACT FROM AUTHOR]

Household air pollution (HAP) is associated with the development of lung cancer, yet few studies investigated the exposure patterns and joint associations with tobacco smoking. In our study, we included 224 189 urban participants from China Kadoorie Biobank (CKB), 3288 of which diagnosed with lung cancer during the follow‐up. Exposure to four HAP sources (solid fuels for cooking/heating/stove and environmental tobacco smoke exposure) was assessed at baseline. Distinct HAP patterns and their associations with lung cancer were examined through latent class analysis (LCA) and multivariable Cox regression. A total of 76.1% of the participants reported regular cooking and 52.2% reported winter heating, of which 9% and 24.7% used solid fuels, respectively. Solid fuel heating increased lung cancer risk (Hazards ratio [HR]: 1.25, 95% confidence interval [CI]: 1.08‐1.46). LCA identified three HAP patterns; the "clean fuel cooking and solid fuel heating" pattern significantly increased lung cancer risk (HR: 1.25, 95% CI: 1.10‐1.41), compared to low HAP pattern. An additive interaction was observed between heavy smoking and "clean fuel cooking and solid fuel heating" (relative excess risk [RERI]: 1.32, 95% CI: 0.29‐2.47, attributable proportion [AP]: 0.23, 95% CI: 0.06‐0.36). Cases resulting from solid fuel account for ~4% of total cases (population attribute fraction [PAF]overall: 4.31%, 95% CI: 2.16%‐6.47%, PAFever smokers: 4.38%, 95% CI: 1.54%‐7.23%). Our results suggest that in urban China, solid fuel heating increased the risk of lung cancer, particularly among heavy smokers. The whole population could benefit from cleaner indoor air quality by reducing using solid fuels, especially smokers. [ABSTRACT FROM AUTHOR]

Household air purifiers have been widely used as an effective approach to improving indoor air quality. Air purifiers can automatically record indoor air quality parameters, providing valuable data resources for in-depth data-driven analysis. This work presents a one-year hourly indoor air quality dataset collected by household air purifiers in 100 residential homes in 18 provinces across 4 different climate zones in China. The data were collected from July 1, 2021, to July 1, 2022. The concentrations of formaldehyde, PM2.5, TVOC, temperature, relative humidity, on/off status and the airflow rate of air purifiers during operations were recorded hourly. The data were carefully screened with possibly missing values imputed using chained equation-based methods if any. The dataset provides a comprehensive and detailed picture of the indoor air quality in residential buildings, enabling evaluations on the cleaning effect of air purifiers, the impact of outdoor climate change on indoor air quality, and the future trends in indoor human behavior. [ABSTRACT FROM AUTHOR]

In order to explore the indoor air quality during different cooking procedures, a very common kitchen in China is selected for experimental research. An indoor air quality meter is used to measure the temperature, relative humidity, and CO and CO2 concentrations of the indoor air above the stove when people cook four different dishes under different ventilation patterns in the kitchen. The results indicate that the heat and gas consumed during cooking are closely related to the temperature and concentrations of CO and CO2. Some cooking procedures such as boiling water are related to the indoor air temperature and relative humidity in the kitchen. In addition, in kitchens without mechanical ventilation, natural ventilation shows a more significant positive effect on controlling temperature, relative humidity, and concentrations of CO and CO2 during cooking procedures. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This study analyzed the applicability of the Passive House standard to office buildings in northern China from an indoor environment perspective. The case building has been auto-monitored continuously since 2017 and a survey for instantaneous and retrospective appraisal of indoor environmental conditions was administered in 2021 during the summer, winter and months in between, referred to as 'transition months'. The results show that indoor environment quality was good, with high satisfaction levels and ultra-low energy consumption; overheating and the need for window opening were observed. The prevalence of sick building syndrome was reduced compared to conventional buildings. This work further determined how comfort parameters such as perceived thermal comfort, indoor air quality and acoustics could affect end-users' appraisal. Findings show that indoor thermal comfort design parameters, particularly in summer, are critical factors affecting users' satisfaction in Passive Houses. We further examined the feasibility of the PMV-PPD index for predicting occupants' perceived comfort and suggested deriving the preferred thermal comfort design parameters for the Chinese market, using long-term data and measurements. These findings provide insights into the localization of Passive Houses in China, thereby improving the acceptance of Passive Houses in what is expected to be a fast growing market. [ABSTRACT FROM AUTHOR]

In winter, many rural people in the coastal areas of northern China burn coal for both cooking and heating. As a result, the rural population is seriously affected by indoor air pollution. To analyze the influence of the location of heating sources on the air quality within rural buildings, 60 buildings with coal heating were surveyed and monitored using an Intelligent Built Environmental Monitor for eight days. In addition, four typical rural buildings with different locations of heating sources were selected for a transient analysis. The peak concentration of CO2 was 2869 ppm in House 1 with a coal-fired stove in the living room. The average particulate matter (PM) levels were 89 μg/m3, 150 μg/m3, and 182 μg/m3 for PM 1.0, PM 2.5, and PM 10, respectively, in House 2 where a stove was situated in a room adjacent to the living room. House 3, where stoves were in separate rooms, had PM 1.0, PM 2.5, and PM 10 values of 25 μg/m3, 39 μg/m3, and 49 μg/m3, respectively, and the lowest CO2 concentration (564 ppm) was found in House 4. The data collected showed that the CO2, PM 1.0, PM 2.5, and PM 10 concentrations within Houses 1 and 2 far exceeded the standard for indoor air quality. The findings suggested that coal-fired stoves, as a heating source, should be situated away from the living room and adjacent rooms, and this change would clearly reduce the concentrations of CO2 and particulate matter. Suitable courtyard ventilation was necessary for houses with two or more heating sources. [ABSTRACT FROM AUTHOR]

To improve the air quality of classrooms in primary and middle schools, and solve the contradiction between indoor air quality and thermal comfort caused by intermittent natural ventilation, a composite negative pressure ventilation mode that combines passive building energy saving design and negative pressure ventilation is proposed. This requires the coordination of related facilities in the classrooms and corridors to achieve, so the optimization design of teaching buildings is studied. On the basis of expounding the principle of compound negative pressure ventilation, firstly, the feasibility of negative pressure ventilation in improving the air quality of classrooms is verified through actual measurement. Then, a digital model of typical classrooms and corridors is established, with a variety of working conditions set up to compare and study related facilities—external wall exhaust fans (power, location), high side windows on internal walls (size, location), and bottom heating (power, Location), etc. on the impact of combined negative pressure ventilation. Through the analysis of the indicators of the various elements of the physical environment (CO concentration, air age, temperature field, and wind speed field) in the classroom in the CFD simulation results, the design parameters and optimal combination modes of related facilities are proposed. Finally, the optimization mode and use strategy of teaching buildings in primary and secondary schools are proposed. The research results show that the combined negative pressure ventilation can save more than 10% energy while improving the air quality and thermal environment in the classroom in winter and summer. Because it has the advantages of light technology and easy operation, it can be widely used in the new construction and renovation of nearly 300,000 primary and secondary schools in China. [ABSTRACT FROM AUTHOR]

In recent years, the indoor air quality (IAQ) of educational buildings has attracted people's attention. As a resting place, the dormitory occupies more than half of the students' time in school. During sleep, the IAQ in dormitories is easily affected by breathing, which in turn affects the sleep quality and mental state of students. In order to study the relevant IAQ during sleep, this paper selected the dormitories of graduate students of different grades in a university in northern China, and monitored the temperature, humidity, CO2, PM2.5, HCHO and TVOC for two weeks during the changing seasons of autumn and winter. In addition, by issuing questionnaires, students made a subjective evaluation of the IAQ. According to the results of objective monitoring data and subjective evaluation, the IAQ changes in student dormitories of different grades, genders, and locations are statistically analyzed, and the correlation between environmental parameters is discussed. The research results show that temperature and humidity basically meet the national standards; indoor PM2.5 is positively correlated with outdoor PM2.5; and HCHO and TVOC are positively correlated with indoor temperature and humidity. Most dormitories lack natural ventilation, and the concentration of CO2 during sleep is too high, which affects the quality of sleep and mental state. [ABSTRACT FROM AUTHOR]

Antenatal depression is associated with adverse birth and long‐term outcomes for mothers and children. Pregnant women spend 90% of time indoors; however, the association between indoor air quality and risk of antenatal depression has not been established. In this study, we aim to determine the total and trimester‐specific association of perceived indoor air quality (PIAQ) with antenatal depression. A total of 2166 pregnant women were enrolled during the first trimester and evaluated during the second and third trimesters in the China Medical University Birth Cohort Study, a prospective pre‐birth cohort study in northeastern China. PIAQ scores were obtained during each of three trimesters, which a higher score indicated a worse indoor air quality. Antenatal depression was screened using an Edinburgh Postnatal Depression Scale (EPDS) and defined as an EPDS score ≥ 9. Prevalence of antenatal depression was 26.7%, 20.6%, and 20.9% during the first, second, and third trimesters, respectively. A higher PIAQ score was positively associated with a depression score throughout pregnancy (β = 0.27, 95% CI = 0.15–0.39). Trimester‐specific adverse PIAQ exposure was associated with a higher depression score in the same trimester, but not with a higher score in a subsequent trimester. A dose–response pattern and incremental increases in risk of depression were observed with calculated adverse PIAQ exposures across all three trimesters, with the highest risk (OR = 3.24; 95% CI = 2.28–4.78) among women with adverse PIAQ across all three trimesters. The hazardous association between adverse PIAQ exposure and risk of depression were less pronounced among women with higher physical activity levels (P for interaction < 0.001). The results of present study provided important evidence that pregnant women's mental health was linked to indoor air quality during pregnancy. These findings could be helpful in the development of guidelines to prevent antenatal depression by improving indoor air quality. [ABSTRACT FROM AUTHOR]

Exposure to formaldehyde causes a variety of adverse health outcomes, while the distributions of indoor formaldehyde in different building types are still not clear in China. In this study, based on the systematic review of previously published data and Monte Carlo simulation, we assessed geographical and temporal distributions of indoor formaldehyde concentrations in residences, schools, and offices across China. A total of 397 studies covered 34 provincial‐level regions since 1986 were collected. The results showed that indoor formaldehyde concentrations in residences, schools, and offices in nationwide were decreasing over years due to the publishment of indoor air quality standards since 2002. During 2011 to 2015, the median concentrations of indoor formaldehyde in newly renovated residences, schools, and offices were 153 μg/m3, 163 μg/m3, and 94 μg/m3, with an exceeding rate of 82%, 46%, and 91% considering a standard threshold of 100 μg/m3 at that time, while the exceeding rate was less than 5% for buildings that were renovated beyond one year. Our findings release the temporal trends and geographic distributions of indoor formaldehyde concentrations in residences, schools, and offices in China in the past 30 years, and provide basic data for the comprehensive evaluation of disease burden attributable to indoor formaldehyde exposure. [ABSTRACT FROM AUTHOR]

Indoor air quality is a critical factor influencing athletic performance, particularly in professional sports settings, yet its impact remains underexplored. This study utilizes a panel dataset from 2516 Chinese Basketball Association (CBA) matches across 20 cities in China between 2014 and 2019. We integrate daily air pollution metrics with player efficiency ratings (PER) to investigate the effects of air quality on individual performance. We find that a 10% increase in the air quality index (AQI) corresponds to a 1.4223 decrease in PER, indicating a strong negative effect of poor air quality on player productivity. Different pollutants have varying effects, with some exacerbating the decline in both overall performance and precision in tasks. Notably, older players and international players exhibit greater resilience to air pollution. These insights contribute to the development of a comprehensive index for assessing work efficiency under varying air quality conditions and suggest targeted strategies to mitigate the negative impacts of air pollution in competitive athletic settings. • Uses technical statistics from players in the Chinese Basketball Association. • The data is mixed with the air quality readings taken every day. • Air pollution impacts productivity by decreasing both overall production. [ABSTRACT FROM AUTHOR]

The last two decades have witnessed rapid urbanization and economic growth accompanied by severe indoor air pollution of volatile organic compounds (VOCs) in China. However, indoor VOC pollution across China has not been well characterized and documented. This study is a systematic review of field measurements of eight target VOCs (benzene, toluene, xylenes, acetaldehyde, p‐dichlorobenzene, butadiene, trichloroethylene, and tetrachloroethylene) in residences, offices, and schools in China from 2000 to 2021. The results show that indoor pollution of benzene, toluene, and xylenes has been more serious in China than in other countries. Spatiotemporal distribution shows lower indoor VOC levels in east and south‐east regions and a declining trend from 2000 to 2021. Moving into a dwelling more than 1 year after decoration and improving ventilation could significantly reduce exposure to indoor VOCs. Reducing benzene exposure is urgently needed because it is associated with greater health risks (4.5 × 10−4 for lifetime cancer risk and 8.3 for hazard quotient) than any other VOCs. The present study enriches the database of indoor VOC levels and provides scientific evidence for improving national indoor air quality standards as well as estimating the attributable disease burden caused by VOCs in China. [ABSTRACT FROM AUTHOR]

Background. Indoor air quality is controlled in the clean operating room (OR) to reduce the risk of surgical-site infections (SSIs). The aim of this study is to assess the usage and management of clean ORs in China and to identify factors associated with the risk of SSIs. Methods. An online survey was distributed to hospitals in China from August 5 to September 5, 2018 via the WeChat account of the Shanghai International Forum for Infection Control and Prevention. The questionnaire consisted of two parts: basic information (hospital type, level, and number of beds) and usage and management (number of ORs, usage time, maintenance mode, test frequency, compliance with current standards, and comfort of healthcare workers). The significance of factors associated with the cleanliness and maintenance of clean ORs was assessed by univariate and multivariate logistic regression analyses. Results. Among 1,308 responding hospitals, 25.7% failed to comply with current standards. "Maintenance mode" had a significant effect on compliance with current standards for clean ORs (p < 0.0001) and "professional" maintenance was superior to "outsource or no" maintenance (odds ratio = 0.511, 95% confidence interval = 0.367–0.711). There was a significant difference in the comfort of healthcare workers in clean ORs that complied with current standards vs. those that did not (39.92% [388/972] vs. 64.28% [216/336], respectively, p < 0.0001). Humidity was the chief complaint among healthcare workers. Conclusion. Maintenance of clean ORs was significantly associated with the compliance of current standards. Noncompliance with current standards was associated with greater risks of SSIs. Maintenance of ORs for prevention of SSIs should consider the costs and benefits. [ABSTRACT FROM AUTHOR]

The residential indoor environment and health have received increasing public interest recently. To improve knowledge of impacts of the residential indoor environment on health status of inhabitants, a Chinese Residential Indoor Environment and Health (CRIEH) survey was conducted from March 2014 to June 2014, and provided the information on 7934 residents in ten provinces and two municipalities. Results showed that prominent indoor environmental issues of households reporting were: "thermal problems in summer" (55%) in the living room; "low humidity in winter" (51%) in the bedroom; "odor" (39%) in the kitchen; "thermal problems in winter" (52%) in the toilet. Moreover, there were significant associations between indoor environment components and self-reported health. The largest association coefficient was found between safety and overall health (0.40). There was a relatively large association coefficient between safety and chronic pain such as joint pain (0.31) and lower back pain (0.29). Allergies had a relatively large coefficient with indoor air quality (0.36). Furthermore, significant associations with the overall indoor environment quality were found for self-reported health even after adjusting for personal characteristics. This study will promote understanding of the complex relationships between the residential indoor environment and occupants' health in China. [ABSTRACT FROM AUTHOR]

The coronavirus (COVID‐19) lockdown in China is thought to have reduced air pollution emissions due to reduced human mobility and economic activities. Few studies have assessed the impacts of COVID‐19 on community and indoor air quality in environments with diverse socioeconomic and household energy use patterns. The main goal of this study was to evaluate whether indoor and community air pollution differed before, during, and after the COVID‐19 lockdown in homes with different energy use patterns. Using calibrated real‐time PM2.5 sensors, we measured indoor and community air quality in 147 homes from 30 villages in Beijing over 4 months including periods before, during, and after the COVID‐19 lockdown. Community pollution was higher during the lockdown (61 ± 47 μg/m3) compared with before (45 ± 35 μg/m3, p < 0.001) and after (47 ± 37 μg/m3, p < 0.001) the lockdown. However, we did not observe significantly increased indoor PM2.5 during the COVID‐19 lockdown. Indoor‐generated PM2.5 in homes using clean energy for heating without smokers was the lowest compared with those using solid fuel with/without smokers, implying air pollutant emissions are reduced in homes using clean energy. Indoor air quality may not have been impacted by the COVID‐19 lockdown in rural settings in China and appeared to be more impacted by the household energy choice and indoor smoking than the COVID‐19 lockdown. As clean energy transitions occurred in rural households in northern China, our work highlights the importance of understanding multiple possible indoor sources to interpret the impacts of interventions, intended or otherwise. [ABSTRACT FROM AUTHOR]

Indoor environmental quality is considered an important indicator of the sustainable development of architecture. It not only reflects the comfort level of occupants in the building but also affects their productivity, particularly in research institutions. However, due to the inherent correlation among various environmental indexes, it is difficult to evaluate the influence of specific physical parameters on the occupant's comfort and research performance. This paper is based on an experiment conducted in a controlled research office in a pharmaceutical research company in the Northeast of China. The controlled research office was equipped with a radiant floor heating system that supplied heating in winter. We recruited 32 researchers and divided them into four subgroups. Each subgroup of researchers was required to conduct daily research activities under 12 different environment combinations. Data were collected from physical environment measurements, questionnaire surveys and performance tests. The results reflected that under the condition of radian floor heating in winter, changes in thermal, visual and acoustic environments could have a significant influence on occupants' satisfaction with the environment. However, the research performance was affected only by thermal and acoustic conditions. There was a weak correlation among thermal, visual, acoustic and indoor air quality comfort. [ABSTRACT FROM AUTHOR]

The weather in the high latitudes of China is cold in winter. The pollution caused by the burning of biomass fuels used in rural individual heating is a great threat to human health. This study finds that the amounts of CO2, CO, PM2.5, and PM10 in the bedroom exceed the standard and the temperature does not meet the standard based on indoor air measurements in rural residential buildings in Liaoning Province in winter. In this study, a mechanical ventilation method which uses flue gas to preheat fresh air is proposed, for the purpose of simultaneously improving the indoor air quality and the thermal environment of rural houses. The flue gas–fresh air heat exchange (FGFAHE) experiment shows that biomass combustion flue gas can increase the outdoor air temperature by 23.7 °C on average. The ventilation experiment shows that the method of mechanical ventilation combined with external window penetration can increase the dilution rate of indoor CO by more than 1 times. The simulation results of six different ventilation schemes show that the ventilation mode of the diagonal opposite side upper air supply and lower exhaust air (DOUSLE) has the best effect on indoor CO prevention and control, and the mode of median air supply is the most beneficial to the indoor thermal environment. [ABSTRACT FROM AUTHOR]

Window opening behavior in residential buildings has important theoretical significance and practical value for improving energy conservation, indoor thermal comfort, and indoor air quality. Climate and cultural differences may lead to different window opening behavior by residents. Currently, research on residential window opening behavior in northwest China has focused on indoor air quality, and few probabilistic models of residential window behaviors have been established. Therefore, in this study, we focused on an analysis of factors influencing window opening behavior and the establishment of a predictive model for window opening behavior. Four typical residential buildings in different locations and building types in Xi'an were selected. The indoor and outdoor environments and window opening states were measured. Subsequently, a multivariate analysis of variance was used to determine the factors that had a significant effect on window opening behavior. Single- and multiparameter logistic regression models for window opening behavior were established. Of all the measured factors, we found that indoor temperature and CO2 concentration, outdoor temperature, and relative humidity had significant effects on window opening behavior, and indoor relative humidity and noise did not. Meanwhile, the temperature was positively correlated with the window opening probability, whereas indoor CO2 concentration and outdoor relative humidity were negatively correlated. The prediction accuracy of the multiparameter model was promising, at almost 75%, and the model can provide theoretical support for modelling residential buildings in Xi'an. [ABSTRACT FROM AUTHOR]

Solid fuels usage may have a negative impact on people's living environment, worsen indoor air quality, thus affect people's health status. Using CFPS panel data from 2010 to 2018, this paper studies the impact of solid fuels usage on life satisfaction of rural residents in China. Through two-stage least squares regression and other methods, we find that the use of solid fuels is negatively correlated with life satisfaction of rural residents. When rural residents use solid fuels for cooking, their life satisfaction will be reduced by around 0.082–0.138 units. Through grouping regression, we found that the negative impact of the use of solid fuels on the life satisfaction of rural residents increases with the increase of the individual's age. Through further mechanism analysis, we found that the negative impact of the use of solid fuels on the life satisfaction may be due to that the use of solid fuels will reduce the probability of individuals being in a healthy state, thus leading to a reduction in labor supply and a decline in income levels. • This paper investigates how solid fuels use affects life satisfaction. • This paper finds that the use of solid fuels is negatively correlated with life satisfaction of rural residents. • This paper enriches the research on the influencing factors of life satisfaction. • This paper provides new insights on understanding residents' life satisfaction. • This paper aids the implementation of the government energy subsidies. [ABSTRACT FROM AUTHOR]

In Chinese northwestern rural households where the indoor air quality is worse than the outside, rural residents face much higher health risks than urban residents. In this study, remote physical sensor devices and detectors technology were used to monitor and calculate the dwelling environmental quality index of 12 dwellings of traditional villages in the Hehuang area of China based on four environmental parameters to assess the indoor air quality of local dwellings. The results show that (1) the DEQI value reached 76 in summer but only 50 in winter, and the indoor dwelling environment quality in the Hehuang area was better in summer than in winter. (2) The S T was only 34 in summer and even lower in winter, at only 10, and low indoor temperatures were a chronic problem for the indoor dwelling spaces throughout the year. (3) In both summer and winter, the S RH reached 86, which was satisfactory overall. (4) In summer, the S CO2 value was 89 and the S PM10 value was 96, reflecting relatively good overall conditions. In winter, the S CO2 value was 65, the concentrations generally increased, and the S PM10 value was equal to 40, with concentrations exceeding the national standard value more than half the time. This study enables local governments and residents to accurately evaluate and analysis existing indoor dwelling environment problems based on this remote sensing technology, enhance the environmental health awareness of local residents, and provide an objective basis for improving the local dwelling environment and developing relevant policies. • The study conduct an evaluation of indoor dwelling environment with remote sensing. • The study make local governments and residents recognize indoor dwelling problems. • It provides better methods for evaluating indoor dwelling environments in rural areas. [ABSTRACT FROM AUTHOR]

[Display omitted] Particulate matter (PM) is an important air pollutant in subway systems. Exposure to high PM concentrations poses a threat to human health and raises concerns. Piston effect can provide the outdoor fresh air to subway stations through station exits, but it also brings PM from tunnels to platforms when the train enters the station. In this paper, a transient numerical model is developed according to an actual subway station and validated by field tests. The model is used to investigate PM 10 concentration at platform induced by train movement. The cumulative PM 10 concentration at platform in one day is calculated according to the train schedule. Platform screen door (PSD) with adjustable vents is studied to control the PM 10 level at platform and energy saving in 27 cities of five climatic zones in China are discussed. The results show that adjustable vent height should be less than 0.70 m to ensure that PM 10 concentrations at platform can be maintained at an acceptable level and the requirement of fresh air can be met. Moreover, energy consumption can be reduced by more than 70 % in different cities compared with the conventional mechanical ventilation system. The optimized adjustable vent can provide an important reference for improving indoor air quality (IAQ) and saving energy consumption of ventilation systems in underground facilities. [ABSTRACT FROM AUTHOR]

Healthy buildings are a deep-level development of green buildings, which can effectively help relieve stress and improve occupants' physical and mental health. In addition, they are is likely to play an important role in preventing the spread of respiratory infectious diseases. Therefore, healthy buildings have attracted worldwide attention. This article reviews the research and development of healthy buildings in China. First, it briefly introduces the definition of healthy buildings, the key elements of evaluation standards, energy conservation measures and new technology applications for healthy buildings, and lessons learned from the global outbreak of SARS-CoV-2. Secondly, it presents the milestones of healthy building development and healthy building projects in China, and the benefits of healthy buildings were also discussed. Finally, the differences in the evaluation systems of healthy buildings between China and other countries were analyzed, the problems of the current policy system of healthy buildings in China were identified, and suggestions for future development were provided. [ABSTRACT FROM AUTHOR]

The study aimed to analyse the potential risk behind kindling behaviour in Chinese rural families and to provide insights for policymakers in environmental health. A cluster survey was performed on 113 participant's families who were living in the countryside in the north of China, using solid fuels for cooking and heating purpose. A questionnaire survey on their kindling behaviour and family information was administrated. Harmful kindling materials including plastic bottles, plastic planting plates, plastic film mulches, plastic bags, waste foams, and medium density fibreboard (MDF) are targeted in the survey. About one third of participant's families have ever used the listed harmful material for kindling. Based on literature review and the exposure proportion estimated from the questionnaire, we estimated the population attributable fractions (PAF) for all cancer type (10.48–19.48%) and type 2 diabetes (15.57–27.86%) attributable to dioxin exposure. The PAF estimates were greater than our expectation from the view of the global estimate PAF for cancer and T2D. Moreover, we found farming families are more likely to use their farming-related plastic byproducts as kindling material. There is a huge knowledge gap in environmental health in rural China. Although we were not able to measure the specific exposure data, our survey provided a new research aspect for environmental health research and health education. Strengthened environmental health education, better relevant laws, regulations, and supporting policies for regulating rural and farming waste disposal are highly recommended for policymakers in China. [ABSTRACT FROM AUTHOR]

As most existing office buildings in China lack fresh air systems for ventilation, natural ventilation with windows remains the main means of improving indoor air quality and adjusting indoor thermal comfort. However, knowledge of the ventilation characteristics of various window-opening forms in actual buildings is limited and current methods for evaluating ventilation performance lack a comprehensive consideration of ventilation rate and thermal comfort. In this study, the ventilation characteristics of different window-opening forms were systematically compared by conducting computational fluid dynamics (CFD) simulations. A full-scale experiment was conducted in a typical office room in a university in Tianjin to validate the CFD simulation. Two ventilation modes (wind-driven cross-ventilation and temperature-driven single-sided ventilation), three window-opening angles, and seven window types were investigated. Additionally, the ratio of the ventilation rate to the absolute value of thermal sensation was used to quantify the indoor natural-ventilation performance. The results showed that a sliding window with a full opening has the highest discharge coefficients of 0.68 and 0.52 under wind-driven cross-ventilation and temperature-driven single-sided ventilation, respectively, and top-hung windows opening both inwards and outwards have better ventilation performance than other window types under the two ventilation modes. This study is applicable to the design and practice of natural ventilation. [ABSTRACT FROM AUTHOR]

Ultrafine particle (UFP) pollution should be controlled to reduce its effects on health. The design of control measures is limited owing to the uncertainty of source contributions in Chinese residences, where indoor UFP pollution is more severe than in Western residences. Herein, a source-specific, time-dependent UFP concentration model was developed by applying an infiltration factor model incorporating coagulation effects. A Monte Carlo framework with the UFP concentration model was employed to estimate the probabilistic distribution of source contributions in Chinese residences. The input parameter distributions were determined based on our survey and previous studies. The annually averaged indoor UFP concentration was estimated at (2.75 ± 1.71) × 10 4 #/cm 3 , ranging from 2.35 × 10 3 to 1.27 × 10 5 #/cm 3 outside the kitchen, and at (5.48 ± 3.08) × 10 4 #/cm 3 , ranging from 2.90 × 10 3 to 1.94 × 10 5 #/cm 3 in the kitchen. Indoor sources contributed more to indoor UFPs, accounting for 61% in the nonkitchen and 80% in the kitchen, surpassing their contribution to indoor PM 2.5 in Chinese residences. Meanwhile, the indoor UFP emission contributions were higher than those in the United States, Canada, and Germany, owing to higher emissions from cooking and cigarette smoking. These results will aid in elucidating human exposure to UFPs and in designing more targeted control measures.

Metro systems play a crucial role in public transportation worldwide. Given that metro stations are unique built environments with a significant volume of daily commuters, ensuring a satisfactory air quality in these spaces becomes paramount. This study involved measurements of indoor air quality (IAQ), staff satisfaction, particulate matter (PM) chemical composition, and heavy metal health risks at a typical metro station in Tianjin over two seasons. Although the air exchange rate was sufficient to maintain a CO 2 concentration less than 1000 ppm, the proportion of staff reporting no sick-building symptoms decreased from 83 % in spring to 25 % in winter. An average mass concentration of PM with an aerodynamic diameter smaller than 2.5 μm (PM 2.5 ) of 68.0 ± 42.2 μg/m 3 and an average PM 1 mass concentration of 51.8 ± 33.3 μg/m 3 were observed on the platform in winter. PM 2.5 contained more metal in winter than in spring. PM 2.5 in winter contained more metal in winter than in spring. With a lower relative humidity in winter, the coefficient of friction between railway wheels and rails increased, thus increasing particle emission. The carcinogenic risk of Cr on the platform was unacceptable. Moreover, the health risks induced by Ba should be investigated. The findings indicate that PM control at metro stationss, particularly on platforms in winter, should be emphasized., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Heat recovery ventilation (HRV) is type of energy saving ventilation. It has been widely used in animal house to alleviate contradiction between thermal comfort and ventilation in recent years. However, air heat exchanger freeze of HRV caused by severe cold weather limited HRV application in northeast China. It is necessary to find an economic way to ensure HRV being operated without freezing. Establish a more reasonable integration of heating and ventilation system in severely cold area. An experiment was conducted in rabbit house during winter in Arun Banner, northeast China. The rabbit house was heated by a coal boiler in the next room. Hot water produced by boiler was supplied to heating radiator inside the rabbit house. The boiler room was warm because of some extra heat release by boiler. To prevent freezing, the boiler room was used to preheat cold fresh air before it entered the heat exchanger. The HRV was installed on the ground of the rabbit house. It was an integration of HRV and boiler heating system. Temperature, relative humidity and concentration of noxious was measured with automatic recording sensor instrument. Data was collected to evaluate the decrease in air pollutants and air temperature of the rabbit house. Preheating effect of the boiler room and the HRV were tested when the system was in operation. The performance of the HRV and prevention of freezing in heat exchanger was evaluated in typical cold weather in northeast China. The economic benefit of the system was analyzed. The results showed that when the HRV and boiler system began to operate, concentrations of ammonia (NH3) and carbon dioxide (CO2) in rabbit house dropped by 46% and 64%, respectively. Moreover, indoor air temperature only dropped by an average of 1.8 ℃ when the outdoor air temperature varied from -15.8 ℃ to -11.8 ℃. It means that the system can significantly improve indoor air quality with barely a slight decline of indoor air temperature. Respiratory and skin disease decreased by 16% and 4%, respectively. It is great potential for better health and production of rabbits. The boiler room heated fresh air from -13.8 ℃ to -3.7 ℃, and the HRV heated fresh air from -1.0 ℃ to 5.5 ℃ on average. No frozen of the heat exchanger was observed. Heated load of the boiler room and the heat recovery load of the HRV were 12.6 kW and 5.0 kW, respectively. Sensible heat recovery efficiency of the HRV was 75.6%. Coefficient of performance of the HRV was 6.2. The system was operated efficiently. The method of freezing prevention ensure HRV in good condition among the whole cold season in northeast China. It is an economic option because the system can operated without extra energy consumption. The return of investment is 3 years in this work condition. The integration of HRV and boiler allowed HRV and boiler heating to operate with high efficiency and solve the contradiction between heating and ventilation in severely cold weather in the rabbit house. This finding can provide a sound reference for the design of animal house heating and ventilation system in severely cold climate northeast China [ABSTRACT FROM AUTHOR]

Due to considerable carbon emissions in building sectors, sustainability transformation is essential for power supply reliability, stability, grid-friendly interaction, and integration with e-transportation. However, building sustainability transformation requires inter-disciplinary and trans -disciplinary platforms for 'material-component-building-district' co-simulations and innovations. In this study, a generic methodology is proposed to comprehensively interconnect nano-scale material and energy systems in thermal transport and thermodynamics, guiding the design and operation for lifecycle sustainability, together with carbon intensity quantification and decarbonisation potential. Afterwards, a cross-scale energy simulation platform is formulated, involving nanoporous materials, innovative components, building integrations, and district energy analytics. The formulated platform can enable synthetical and comprehensive analysis on thermodynamic performances, energy performances, energy conversion and management, throughout integrated cross-disciplinary approaches by overcoming performance overestimation or underestimation of traditional single-stage approaches. The application of the platform quantifies the decreasing magnitude of energy consumption for PCM microcapsule wall, self-cleaning façade coating, clear thermal resistant cleaning glass coating, evaporative cooling & solar PV roof, volatile organic compound (VOC) absorption for indoor air quality (IAQ) control, building integrated photovoltaics (BIPVs), solar thermal collectors and 10-kW wind turbine. Afterwards, dynamic interaction between real buildings and digital twin models was realized for fast computation and prediction, labour cost and initial investment cost saving, long-term performance analysis. Both historical database and digital twin-generated database can promote the development of machine learning (ML) models, through data preparation, hyperparameter optimization, model training, testing, and validation. The proposed approach and formulated platform can enable synthetical and comprehensive analysis on building sustainability, throughout integrated cross-disciplinary approaches for 2060 carbon neutrality in China. [Display omitted] • A cross-scale simulation platform with nanoporous material and component innovation. • Climate change on thermodynamics and energy performance in thermal transport. • Quantification on carbon intensity and decarbonisation with technology innovations. • Roles of artificial intelligence in cross-scale energy simulations. • Climate adaption and model predictive control with hyperparameter optimization. [ABSTRACT FROM AUTHOR]

Particulate matter (PM) from different sources exhibits diverse chemical and physical characteristics, and it is an essential carrier of toxic chemicals. Ignoring PM properties is inappropriate for indoor air quality (IAQ) control in places with internal sources, such as metro stations. PM control measures aimed at health protection should be established based on PM health effects. The current PM control limit for metro stations may be insufficient for health protection. It is important to find a method that comprehensively evaluates PM features to set PM exposure limits. This study evaluated the health risks induced by chemical components and the oxidative potential of PM in the Tianjinzhan metro station. A PM control strategy was suggested based on health effect analysis. PM on the platform had notable underlying adverse health effects. An in-depth toxicology analysis was suggested to assess the high Ba and Mn concentrations in PM. The risk from Cr raised concern regarding the potential for carcinogenicity. As a potential composite index, the dithiothreitol (DTT) activity may be appropriate to evaluate the general adverse health effects caused by PM. The DTT activity of the platform was 3.3–5.4 times that of the ventilation shaft. Removing a unit mass of PM1 in the station hall would produce more health benefits than the removal of a unit mass of PM2.5. However, the DTT results indicated that control strategies on the platform should first focus on PM2.5, which would achieve the same protection effect as that when the PM1 mass concentration is decreased by the same level. A revision of the PM2.5 control limit for China metro stations was recommended to control oxidative potential on the platform. [Display omitted] • Indoor PM health effects could be quantified by oxidative potential using the DTT assay. • Railroad-related PM sources may lead to a potential health risk concern on the platform. • Removing a unit-weight PM2.5 from the platform brings the same health benefit as a unit-weight PM1. • PM control should focus on PM1 for the station hall, but PM2.5 for the platform. • The platform required air purification to control PM2.5 concentration. [ABSTRACT FROM AUTHOR]

Indoor air quality (IAQ) of urban public transportation stations (UPTS) has adverse health impacts on the station employees and commuters. However, there is a lack of comprehensively evaluations of IAQ in waiting rooms of UPTS. Therefore, it is crucial to select appropriate air quality indexes (including fuzzy synthetic index (B), comprehensive index (P), I 1 index, and indoor air quality index (IAQI)) to assess air quality and potential health risks. Our study is a subsample of the CPPEHS 2019 study, which included 224 UPTS in 126 cities of China. We found that P index showed an excellent air quality rate of 95.96% in the railway stations and 83.19% in the inter-city bus stations. The P index was correlated with UPTS usage years, useable area, and per passenger useable area. Furthermore, waiting rooms in UPTS with good (OR = 1.9187, 95% CI: 1.1204, 3.2859) and bad (OR = 2.0854, 95% CI: 1.2182, 3.5698) air quality evaluated by P index had a higher risk of rhinitis compared to those with excellent air quality. Similarly, UPTS with good (OR = 2.2202, 95% CI: 1.3427, 3.6711), bad (OR = 1.7897, 95% CI: 1.0807, 2.9637), and serious (OR = 1.7478, 95% CI: 1.0098, 3.0250) air quality evaluated by P index were associated with a higher risk of pharyngitis. These findings suggested that P index is the optimal index for assessing air quality in UPTS, while IAQI may exaggerate indoor air pollution and the B index may underestimate it. Overall, this study aims to identify and evaluate the more suitable air quality index (P) in nationwide UPTS, providing valuable insights for control of IAQ and guiding the air quality management and standards. • The evaluation of indoor air quality in urban public transportation stations (UPTS) currently lacks a reliable index. • Four indoor air indexes were calculated to evaluate the air quality of UPTS. • Comprehensive index (P) is the optimal index to evaluate the air quality and health risks in UPTS. [ABSTRACT FROM AUTHOR]

The indoor air quality has a direct impact on human health. In order to obtain the current status of indoor air quality in typical sports buildings in hot summer and cold winter climate zones in China, indoor badminton courts in 10 cities in Hubei Province in this climate zone were selected as research objects for field testing of indoor environmental parameters in spring and autumn, and predict air quality parameters for non-testing times. All the tested stadiums are naturally ventilated in non-event conditions, and the average daily indoor CO 2 concentration was 526.78 ppm in spring and 527.63 ppm in autumn, and the average daily PM 2.5 concentration was 0.035 mg/m 3 in spring and 0.024 mg/m 3 in autumn, all of which met the requirements of GB/T 18883-2022, the average concentration of CO 2  ≤ 1000 ppm and PM 2.5  ≤ 0.05 mg/m 3 . The indoor CO 2 concentration and PM 2.5 concentration of the tested badminton halls under natural ventilation gradually increased with the accumulation of exercise time, making the indoor air quality of the badminton halls decrease, which would negatively affect the health of the people exercising in this environment., (© 2024. The Author(s).)

Indoor air pollution resulting from volatile organic compounds (VOCs) is a significant health concern, especially formaldehyde. Therefore, predicting indoor formaldehyde concentration is essential for environmental control. In this research, the authors develop a thermal and wet coupling calculation model of porous fabric that considers the influence of different phases of wet components and the coupling effect of heat and humidity on formaldehyde migration. We propose a modified calculation method of the formaldehyde mass transfer characteristic parameters of fabric to obtain the diffusion coefficient D and partition coefficient K. The heat and humidity coupling model and formaldehyde mass transfer model of fabric are simultaneously solved, and the authors analyze the influence mechanism of fabric loading rate, fabric type, temperature, and humidity on indoor formaldehyde mass transfer characteristics. We study the variation trend of fabric formaldehyde mass transfer characteristics coefficient and the temporal and spatial distribution of indoor formaldehyde concentration. The theoretical model is applied to practical problems by pre-evaluating the indoor formaldehyde concentration of decorated residential buildings in typical climate areas of China before occupancy. The authors obtain the variation rule of indoor formaldehyde concentration of residential buildings under typical hot and humid climate conditions, building materials, furniture, and fabrics. To provide theoretical support for indoor environmental control and human health protection. [Display omitted] • The VOC mass transfer process and heat and moisture transfer process of fabric are considered in coupling. • The influence of different phases of wet components is considered on VOC migration. • A calculation method for fabric's VOC mass transfer characteristic parameters is proposed. • The influence mechanism of fabric loading rate, fabric type, temperature, and humidity on indoor VOC migration are analyzed. [ABSTRACT FROM AUTHOR]

[Display omitted] • State of the art on real-time sensors for indoor air evaluation is reviewed. • High spatiotemporal resolution data from real-time sensors is favorable for the risk assessment of indoor air pollution. • Challenges including performance, stability and calibration of sensors still remained. • Sensors with high performance, low price, and more target pollutants are expected. People generally spend most of their time indoors, making indoor air quality be of great significance to human health. Large spatiotemporal heterogeneity of indoor air pollution can be hardly captured by conventional filter-based monitoring but real-time monitoring. Real-time monitoring is conducive to change air assessment mode from static and sparse analysis to dynamic and massive analysis, and has made remarkable strides in indoor air evaluation. In this review, the state of art, strengths, challenges, and further development of real-time sensors used in indoor air evaluation are focused on. Researches using real-time sensors for indoor air evaluation have increased rapidly since 2018, and are mainly conducted in China and the USA, with the most frequently investigated air pollutants of PM 2.5. In addition to high spatiotemporal resolution, real-time sensors for indoor air evaluation have prominent advantages in 3-dimensional monitoring, pollution peak and source identification, and short-term health effect evaluation. Huge amounts of data from real-time sensors also facilitate the modeling and prediction of indoor air pollution. However, challenges still remain in extensive deployment of real-time sensors indoors, including the selection, performance, stability, as well as calibration of sensors. In future, sensors with high performance, long-term stability, low price, and low energy consumption are welcomed. Furthermore, more target air pollutants are also expected to be detected simultaneously by real-time sensors in indoor air monitoring. [ABSTRACT FROM AUTHOR]

[Display omitted] • The contribution of influential factors on the change of indoor PM 2.5 is evaluated. • A method for quantifying the monthly variation pattern of PM 2.5 concentrations. • The ambient PM 2.5 contributions are varied in each month. • N, M, and W-shaped PM 2.5 variation patterns are found from observed data. • Time-specific indoor air interventions can help seasonally target management. Indoor air quality is crucial to the physical and psychological health of students because they spend a large portion of their time in classrooms. Indoor PM 2.5 concentrations are affected by various complex factors, such as outdoor PM 2.5 , temperature, and relative humidity. However, how and to what extent these factors contribute to PM 2.5 concentrations remains unclear. Recently, black-box (e.g., neural networks) and white-box (e.g., linear regression) models have been applied to analyze their contributions. However, these models either have low interpretability or are insufficient for revealing complex nonlinear relationships. To address these issues, indoor PM 2.5 concentrations in ten classrooms were monitored for twelve months at a primary school in North China, and the contribution of various influential factors was calculated using partial derivatives based on this approach. This method can automatically identify linear and nonlinear relationship models from a large amount of data without a prior hypothesis. Experimental results showed that: (1) The contribution of each influential factor to indoor PM 2.5 varied greatly in the 12 months based on the identified relationships. In addition, no single relationship pattern was identified that could universally describe the factors influencing indoor PM 2.5. (2) The method developed in this study can automatically identify linear and nonlinear relationship models with white-box structures from a large amount of data without a prior hypothesis, which is more interpretable and applicable than other baselines. (3) Targeted solutions can be drawn by the contribution of each factor and three types of relationship curves (i.e., N -shaped, M−shaped, and W-shaped), the latter of which is the Pareto front revealed by our results. The study offers informative results regarding the temporal dynamics of indoor PM 2.5 concentrations and quantitative contributions of influential factors based on timely long-term data, which promotes the understanding of changes in indoor PM 2.5 concentrations. This also demonstrates the promising potential of using low-cost online sensors to conduct informative measurements that guide schools to more effectively improve classroom air quality. [ABSTRACT FROM AUTHOR]

The residential indoor environment has been acknowledged as one of the main settings affecting quality of life. However, complex relationships exist between residential indoor environment and quality of life. Most studies frequently tend to address a narrow range of residential environmental factors and associated quality of life. Therefore, this study is to identify the relationships between overall residential indoor environment and quality of life, and how relationships can be influenced by potential confounding factors, based on the Pan-China residential environment and health survey data. Results showed that the prominent residential environmental issues reported by participants were thermal problems. There was a statistically significant association between the increase in physical/mental health conditions and the reduction in reported frequency of residential environmental problems, including thermal, indoor air quality, lighting, acoustic, hygiene, safe and security environment, even after adjustment for age, sex, education, smoking status, drinking status, and number of residents per household. Furthermore, the significant combined effects on physical/mental health were found for paired residential environmental problems, including temperature and humidity, thermal environment and air quality/noise/mold, air quality and noise, and fall risks and wet problems, after adjustment for confounders. This paper attempted to disentangle complex relationships between residential indoor environment and quality of life, which will provide a basis to develop strategies for improving quality of life. • The most prominent residential indoor environmental issues were thermal problems. • Association between indoor environmental factors and quality of life was established. • Significant combined effects of environmental factors on quality of life were found. [ABSTRACT FROM AUTHOR]

The flow-field characteristics of high-temperature airflow and particle distributions generated from the running furnace during smelting process in foundry shop were studied by on-site measurements and theoretical analysis in this work. A theoretical model was proposed to describe the dispersion characteristics of the high-temperature buoyant jet flow and plume induced by the furnace with two typical opening modes. The coupling effects of the heat source features and environmental factors were emphatically discussed by comparing the trajectory, cross-section diameter, velocity and temperature decay, and volumetric flow rate during the dispersion process. Results show that in the large foundry shop with natural ventilation, there is a vertical temperature gradient of 0.1–0.4 °C/m, which can make the pollutant locked in the workshop and weaken the entrainment of the thermal flow. The crossflow is a non-negligible factor, which causes the dispersion trajectory of the pollutant flatter and induces a long travelling distance along the horizontal direction. The indoor particle concentration when the furnace opens concentration seriously exceeds the limits in the existing indoor air quality standard of China. This work is expected to give suggestions on ventilation designs and arrangements of the exhaust port or device in industrial environments. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the characteristics of, exposure to, and factors influencing gas-phase and PM 2.5 -bound phthalates (PAEs) in nail salons. Data on both indoor and outdoor gas-phase and PM 2.5 -bound PAEs, carbon dioxide (CO 2 ), temperature, and relative humidity were collected in nail salons. We also used questionnaires to survey building characteristics and occupants' behaviors. The average total gas-phase and PM 2.5 -bound PAE concentrations indoors were higher than those outdoors by 6 and 3 times, respectively. Diethyl phthalate, diisobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP), and di-(2-ethylhexyl) phthalate (DEHP) were the predominant compounds among both the gas-phase and PM 2.5 -bound PAEs in indoor air. The volume of the salon's space or the difference of indoor and outdoor CO 2 concentrations (dCO 2 ) was significantly associated with indoor PAE concentrations. The ratios of PM 2.5 -bound to gas-phase PAEs, especially high-molecular-weight PAEs, were positively associated with the dCO 2 concentrations. Higher ratios of indoor to outdoor PM 2.5 -bound DiBP, DnBP, and DEHP concentrations were discovered when more clients visited each day. Building characteristics, ventilation conditions, and occupants' activities have influences on the gas-phase and particle-phase PAEs. The study identifies the characteristics of gas-phase and PM 2.5 -bound PAEs in nail salons and their influencing factors., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

[Display omitted] • Exposure inequality was contrary between ambient and household PM 2.5 exposure. • The poorest experienced the highest PM 2.5 exposure though ambient exposure was low. • Negative concentration index gradually increased indicating a transition towards equality. • Aggressive countermeasures reduced ambient exposures but benefited people disproportionately. • Spontaneous clean household energy transition effectively reduced the exposure inequality. The society has high concerns on the inequality that people are disproportionately exposed to ambient air pollution, but with more time spent indoors, the disparity in the total exposure considering both indoor and outdoor exposure has not been explored; and with the socioeconomical development and efforts in fighting against air pollution, it is unknown how the exposure inequality changed over time. Based on the city-level panel data, this study revealed the Concentration Index ( C ) in ambient PM 2.5 exposure inequality was positive, indicating the low-income group exposed to lower ambient PM 2.5 ; however, the total PM 2.5 exposure was negatively correlated with the income, showing a negative C value. The low-income population exposed to high PM 2.5 associated with larger contributions of indoor exposure from the residential emissions. The total PM 2.5 exposure caused 1.13 (0.63–1.73) million premature deaths in 2019, with only 14 % were high-income population. The toughest-ever air pollution countermeasures have reduced ambient PM 2.5 exposures effectively that, however, benefited the rich population more than the others. The transition to clean household energy sources significantly affected on indoor air quality improvements, as well as alleviation of ambient air pollution, resulting in notable reductions of the total PM 2.5 exposure and especially benefiting the low-income groups. The negative C values decreased from 2000 to 2019, indicating a significantly reducing trend in the total PM 2.5 exposure inequality over time. [ABSTRACT FROM AUTHOR]

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 CO 2 , 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. • The city-level IAQ of office buildings in different climate zones was investigated. • Subjective and objective method were both carried out to investigate IAQ. • The impact of the floor height on the pollutant concentrations was investigated. • The inhalation exposure risk from different cities was compared. • Cancer risk in Kunming city has the highest level for both male and female. [ABSTRACT FROM AUTHOR]

Formaldehyde is concerned as an important indoor carcinogen. While contribution of outdoor formaldehyde to indoor concentration is recognized, long-term measurement about its impact on indoor environments remain missing. We measured both outdoor and indoor formaldehyde concentrations for over one year in Nanjing (east-central China) and calculated the outdoor/indoor (O/I) ratios. 64.8% of the measured outdoor concentration have exceeded the chronic reference exposure criteria of 0.009 mg/m3 set by Office of Environmental Health Hazard Assessment (OEHHA). The outdoor concentration was highest in summer with median value of 0.020 mg/m3 and lowest in spring with median value of 0.009 mg/m3. Diurnally, outdoor formaldehyde concentration was highest at noon with median value of 0.013 mg/m3 and lowest at night with median value of 0.01 mg/m3. Health analysis revealed that cancer risk by exposure to this concentration level is 1.6 × 10−4, higher than threshold limit of 10−6. In addition, the median O/I ratios are 0.18 and 0.27 in two offices, indicating that outdoor formaldehyde contributes to indoor concentrations by about one quarter. The change of O/I ratio also shows a similar seasonal and diurnal trend as outdoor concentrations (highest in the summer in a year and at noon in a day). Outdoor formaldehyde concentration is therefore not negligible as a contributor to indoor concentration, especially as indoor concentration limit gets continuously lowered. This factor should be taken into account in indoor air quality design and maintenance. [ABSTRACT FROM AUTHOR]

Formaldehyde (HCHO) is a well known carcinogen. While most studies investigate emission from wood-based materials, knowledge about releasing of HCHO by natural gas combustion is quite limited. This study conducted field measurements in 9 households to address this issue. We found that emission factor is mainly in the range of 50-200 mg&#95;HCHO/m 3 &#95;natural gas (median value is 85 mg/m 3 ). Emission rate mainly falls into a range of 0.1-0.4 mg&#95;HCHO/min (median value is 0.16 mg/min). It is also revealed that as the natural gas flow rate increases, the emission factor decreases with a statistically significant Spearman correlation coefficient of -0.46 (p < 0.05). The emission rate shows an opposite trend with a Spearman correlation coefficient of 0.48 (p < 0.05). Formaldehyde generated by natural gas combustion in kitchens can quickly disperse to an adjacent living room when kitchen door is open. A range hood can effectively remove formaldehyde in kitchens if kitchen window is open and kitchen door is closed. Its performance would decrease by half otherwise. These results imply a health co-benefit of reducing household usage of carbon-based natural gas in the age of carbon neutrality aiming climate change., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Air pollution, including PM 2.5 concentration in Ulaanbaatar (capital of Mongolia) is a serious matter of concern. As the majority of households use coal in large areas of the city, indoor air quality is also posing a serious risk to human health. This study investigated the concentration of polycyclic aromatic compounds (PAHs) in indoor particulate matter (PM 2.5 ) in 10 non-smoker households. Sampling was conducted in winter of 2018, between 27 January and 09 February. Concentrations of PM 2.5 in the indoor air of households ranged between 62.8 and 324.8 µg m -3 . Total concentration of PAHs also varied in a relatively wide range, between 46.2 and 175.7 ng m -3 . Five-ring PAHs represented a considerably high fraction of total PAHs between 25 and 53%, benzo[b]fluoranthene (BbF) and benzo[a]pyrene (BaP) were the two predominant compounds within five-ring PAHs. Significant correlation was found between indoor and outdoor particulate matter levels in wintertime. Considering individual characteristic PAHs, heavier PAHs homologues (4- to 5-ring and 6-ring PAHs) were detected in all households, which suggested the influence of coal combustion and traffic exhaust. Health risk of children attributed to PAHs inhalation was assessed by taking into account the lifetime-average daily dose (LADD) and corresponding lifetime cancer risk. Lifetime average daily dose for children in only one household were slightly higher than health-based guideline level (1.0 × 10 -5 ), defined by WHO, whereas LADD for adults and children of other households were within acceptable limit. The cancer risks from the exposure of children to air pollutants in all households except HH-3 were found high. In the Vibrio fischeri bioluminescence inhibition assay, according to the toxic unit (TU) values of indoor PM 2.5 from ten households, all samples were classified as toxic., (© 2022. The Author(s).)

Air pollution is a major health hazard. The traditional habits and unique ethnic fire culture in Hunan Tujia region result in the long-term exposure of residents, especially elderly people, to pollutants. In this study, we conducted field monitoring and assessment of indoor pollutants in the residential houses of Hunan Tujia families and subsequently visualised and simulated fire pollutants in representative residential houses by using fire-dynamic-simulator software. Pollutant-control strategies, using passive smoke collectors and resizing windows, were proposed and simulated for validation. The results revealed that passive smoke collectors reduced the pollutant concentration in the hall house by 43.96%. Furthermore, the optimal window size was 1500 mm × 1500 mm, and the most reasonable windowsill height of the firepit was 1800 mm. The results of the study can be used to improve the indoor air quality of Tujia dwellings and mitigate the adverse health effects of exposure to indoor air pollution without restricting ethnic beliefs and traditional customs.

Due to the low winter temperatures in rural areas of Northeast China, biomass fuels are widely used for heating and cooking, resulting in increased concentrations of PAHs in rural indoor areas during the heating period and threatening human health. Therefore, exploring the pollution characteristics, source localization, and risk assessment of indoor PAHs in rural Northeast China is of great significance for improving rural indoor air quality. In this study, PAHs were collected from a residential building in rural Northeast China for one consecutive year (January 2020–December 2020), and their concentrations were determined to explore the distribution patterns and sources of PAHs to further assess the carcinogenic risk of PAHs to humans. The results of the study showed that the average concentration of indoor PAHs in rural areas during the heating period (93.02 ng/m3) was about 1.81 times higher than that of the non-heating period (51.26 ng/m3). The main sources of PAHs were mixed combustion of biomass and coal, motor vehicle emissions, and domestic waste combustion. The level of indoor PAHs pollution has posed a carcinogenic risk to the health of the rural population in the Northeast. [ABSTRACT FROM AUTHOR]

The tunnel ventilation system is usually adopted to create the indoor environment in poultry buildings in China. However, it is difficult to maintain an appropriate indoor temperature to cause the cold stress and reduce the production performance of chickens in winter. To address it, a novel double-duct ventilation system was proposed by combing the advantages of the exhaust air heat recovery system and the perforated duct ventilation system in this study. The indoor airflow pattern, air temperature distribution, NH 3 concentration distribution, and air age distribution in a laying hen building with the novel double-duct ventilation system were compared with the traditional tunnel ventilation system by using computational fluid dynamics (CFD) method. The results show that (1) the novel double-duct ventilation system can increase the average indoor temperature by 4.4 °C to maintain a warmer indoor environment, owing to the heat recovery from the exhaust air; (2) the in-homogeneity coefficients of indoor air velocity, temperature, NH 3 concentration, and air age are decreased by 38.5%, 66.7%, 35.3%, and 30.8%, respectively, to create a more uniform indoor environment; (3) although the heat recovery efficiency is 33.2% owing to the small heat exchange area, the coefficient of performance (COP) is as high as 6.4 and the payback period is only about 5 months. Therefore, the novel double-duct ventilation system can improve the ventilation performance and create a better indoor environment with low cost. It will provide a new method and theoretical guidance for the ventilation design in poultry buildings. • Novel double-duct ventilation system with exhaust air heat recovery was proposed. • Indoor temperature is increased by 4.4 °C to maintain a warmer indoor environment. • Distribution of air velocity, temperature, NH 3 concentration, and air age is uniform. • Heat recovery efficiency is 33.2%, but coefficient of performance is as high as 6.4. [ABSTRACT FROM AUTHOR]

It is a critical task for sustainable development in urban China to reduce energy consumption in residences while maintaining a healthy and comfortable indoor air environment. With the popularization of fresh air systems, it becomes important to optimally control them. Previous studies usually set the control strategies first, and then evaluate the resulting indoor air quality and energy consumption. A control strategy for a fresh air system that yields acceptable indoor air quality with minimum energy consumption, that is "optimal control," has not yet been identified. In this study, we developed an inverse problem approach using a variation method to solve this problem. For multiple target indoor pollutants, the principle of the optimal control strategy was to ensure the max [C i,in /C i, st ] = 1 (i = 1,2, ...m), where C i,in and C i,st are the concentrations of indoor air pollutant i and the corresponding threshold in the standard. As an illustrative example, we compared our optimal control strategy to the traditional constant air flow rate strategy in a Beijing reference bedroom. The optimal control strategy guaranteed acceptable indoor air quality during hazy days while the traditional strategy did not. Moreover, the optimal strategy can be projected to save 8.7% annual energy consumption and 15% of the operation cost. • We present an inverse problem approach to determine optimal control of fresh air systems. • This strategy yields acceptable indoor air quality with minimum energy consumption. • The non-steady condition and time-averaged concentration standards are considered. • An example shows that the optimal strategy saves 8.7% annual energy consumption. [ABSTRACT FROM AUTHOR]

Characterization of indoor ultrafine particles (UFPs, diameter <100 nm) in residences has been of great interest. However, insufficient information was presented with respect to the characteristics of typical occupants' activities and indoor UFP source emissions under actual conditions. In this study, a field investigation including questionnaire survey (N = 395) and field measurement (N = 38) was conducted in urban residences in two cities of the Yangtze River Delta region of China. The results indicate that outdoor air temperature was identified to be positively correlated (r = 0.106, p < 0.05) and the most influential factor on window-opening behaviors in living room and bedroom. Instead, most of residences prefer to keeping kitchen window opening and kitchen door closing nearly the whole year. Range hood usage accompanied with opening kitchen window was the most popular ventilation mode in kitchen. Indoor UFPs were presented with concentration level of 9799 ± 5036 counts/cm3 in winter, significantly higher than that in summer (6655 ± 2707 counts/cm3) and transition season (6230 ± 1710 counts/cm3), and sharply fluctuated with cooking activities. During the non-cooking periods, however, UFPs in living room and bedroom were mostly derived from outdoors (68.99%–96.95%) in summer and indoors (79.33%–85.66%) in winter. Further quantitative analysis indicates that the emission rate in the monitored kitchens was 0.693 ± 1.215 × 1013 counts/min in the whole process of cooking, greatly depended on the cooking methods and dish menus. The study could be a reference of better understanding impacts of occupant behaviors on indoor UFP pollution in residential buildings. • Typical occupant activities and UFP emissions in urban residences are characterized. • Outdoor air temperature mostly impacts on window-opening behavior except in kitchen. • Outdoors contribute mostly in summer but the opposite in winter during non-cooking. • The emission rate in kitchen is mostly depended on cooking method and dish menu. [ABSTRACT FROM AUTHOR]