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This article examines the indoor air quality (IAQ) in coal-heating rural residential buildings in Northern China during the heating period. The study found that many households had poor indoor air quality, with high levels of CO2, formaldehyde, and PM2.5. The study also discovered that indoor PM2.5 was primarily caused by indoor activities rather than outdoor pollution. The findings emphasize the need for improving IAQ in rural areas and provide data to support future interventions. The study suggests using appropriate ventilation methods and clean fuel for cooking to improve indoor air quality. [Extracted from the article]

In this paper, a simple model is proposed for predicting the thermal energy requirements of greenhouses in Europe. The model estimates the annual heating requirements and the maximum required heating power, along with the corresponding heating and zero-energy operating periods. It is based on the greenhouse technical data (the overall heat loss coefficient, cover transmission, sensible absorbance), the cultivation conditions (temperature range), and the meteorological data (solar radiation and ambient temperature) according to the site characteristics (longitude and latitude). The model results can be obtained using a hand calculator. The model results are compared with those of a detailed model simulating a greenhouse's thermal performance and they agreed with real data from the literature. Moreover, a model sensitivity analysis revealed the effect of various factors on the greenhouse's energy requirements. The results proved that the most significant factor affecting heating requirements, the maximum heating power, and heating periods is the latitude of the greenhouse site, whereas zero-energy periods are primarily influenced by the plant cultivation temperature range and then by the latitude. According to our findings, in lower latitudes (40 to 50 degrees), heating requirements range from 250 to 430 kWh/m2/y, whereas, in higher latitudes (50 to 60 degrees), heating needs range from 430 to 650 kWh/m2/y. [ABSTRACT FROM AUTHOR]

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The effects of chemical components of ambient fine particulate matter (PM 2.5) on human early maternal−fetal interface are unknown. We estimated the associations of PM 2.5 and component exposures with placental villi 8-hydroxy-2′-deoxyguanosine (8-OHdG) in 142 normal early pregnancy (NEP) and 142 early pregnancy loss (EPL) from December 2017 to December 2022. We used datasets accessed from the Tracking Air Pollution in China platform to estimate maternal daily PM 2.5 and component exposures. Effect of average PM 2.5 and component exposures during the post-conception period (i.e., from ovulation to villi collection) on the concentration of villi 8-OHdG were analyzed using multivariable linear regression models. Distributed lag and cumulative effects of PM 2.5 and component exposures during the periovulatory period and within ten days before villi collection on villi 8-OHdG were analyzed using distributed lag non-linear models combined with multivariable linear regression models. Per interquartile range increase in average PM 2.5 , black carbon (BC), and organic matter (OM) exposures during the post-conception period increased villi 8-OHdG in all subjects (β = 34.48% [95% CI : 9.33%, 65.42%], β = 35.73% [95% CI : 9.08%, 68.89%], and β = 54.71% [95% CI : 21.56%, 96.91%], respectively), and in EPL (β = 63.37% [95% CI : 16.00%, 130.10%], β = 47.43% [95% CI : 4.30%, 108.39%], and β = 72.32% [95% CI : 18.20%, 151.21%], respectively), but not in NEP. Specific weekly lag effects of PM 2.5 , BC, and OM exposures during the periovulatory period increased villi 8-OHdG in all subjects. Ten−day cumulative and lag effects of PM 2.5 , BC, and OM increased villi 8-OHdG in all subjects and EPL, but not in NEP; and the effects of OM were robust after adjusting for BC, ammonium, nitrate, or sulfate in two-pollutant models. In conclusion, placental oxidative DNA damage in early pregnancy was associated with maternal exposure to PM 2.5 , especially its chemical components BC and OM. [Display omitted] • The first study on effects of PM 2.5 chemical components on the human early placenta. • Periovulatory and post-conception PM 2.5 , BC, and OM exposures increased villi 8-OHdG. • PM 2.5 , BC, and OM induced placental DNA damage in early pregnancy especially in EPL. • OM was the component with the strongest effects in this study, followed by BC. • PM 2.5 , BC, and OM increased villi 8-OHdG all year especially during heating period. [ABSTRACT FROM AUTHOR]

In the climatic conditions of Ukraine, which are characterised by a long heating period, considerable energy requirements for heating lead to an increase in energy efficiency requirements. A substantial reduction in the energy consumption of buildings while ensuring comfort conditions will be facilitated by the inclusion of a model of human thermal comfort in the complex “heat source – fencing” system. The purpose of this study was to find the factors affecting the internal heat capacity and, accordingly, the thermal inertia of the building and further take these factors into account upon assessing the thermal condition and parameters of thermal comfort of building rooms. The object of this study was the educational and administrative building of the National University of Life and Environmental Sciences of Ukraine. Many studies were carried out, namely full-scale measurements of heat flows and temperatures on the surfaces of samples of the building’s wall structure were carried out in a special climate complex that allows artificially creating external and internal thermal conditions of premises. It was found that the insulation of the structure with a layer of expanded polystyrene PSB-15, 100 mm thick, reduces heat losses through the wall panel by almost half. An algorithm for controlling the heat release process was developed, considering the internal heat capacity of the building. Compared to the “linear” dependence, this allows more accurately adjusting the schedule of heat carrier release to the heating system of a public building during the introduction of the alternating mode of its operation. The temperature deviation range is reduced by 4–6 °C, which allowed saving up to 10-12% of the consumed heat energy for the heating needs of the research object, provided that the normalised values of the internal temperature of the premises are maintained. Intermittent operation of the heating system of public buildings, the expediency of which is justified in this study, can be recommended for implementation in the structures of higher educational institutions of Ukraine.

In this paper, a simple model is proposed for predicting the thermal energy requirements of greenhouses in Europe. The model estimates the annual heating requirements and the maximum required heating power, along with the corresponding heating and zero-energy operating periods. It is based on the greenhouse technical data (the overall heat loss coefficient, cover transmission, sensible absorbance), the cultivation conditions (temperature range), and the meteorological data (solar radiation and ambient temperature) according to the site characteristics (longitude and latitude). The model results can be obtained using a hand calculator. The model results are compared with those of a detailed model simulating a greenhouse’s thermal performance and they agreed with real data from the literature. Moreover, a model sensitivity analysis revealed the effect of various factors on the greenhouse’s energy requirements. The results proved that the most significant factor affecting heating requirements, the maximum heating power, and heating periods is the latitude of the greenhouse site, whereas zero-energy periods are primarily influenced by the plant cultivation temperature range and then by the latitude. According to our findings, in lower latitudes (40 to 50 degrees), heating requirements range from 250 to 430 kWh/m2/y, whereas, in higher latitudes (50 to 60 degrees), heating needs range from 430 to 650 kWh/m2/y.

In the climatic conditions of Ukraine, which are characterised by a long heating period, considerable energy requirements for heating lead to an increase in energy efficiency requirements. A substantial reduction in the energy consumption of buildings while ensuring comfort conditions will be facilitated by the inclusion of a model of human thermal comfort in the complex "heat source -- fencing" system. The purpose of this study was to find the factors affecting the internal heat capacity and, accordingly, the thermal inertia of the building and further take these factors into account upon assessing the thermal condition and parameters of thermal comfort of building rooms. The object of this study was the educational and administrative building of the National University of Life and Environmental Sciences of Ukraine. Many studies were carried out, namely full-scale measurements of heat flows and temperatures on the surfaces of samples of the building's wall structure were carried out in a special climate complex that allows artificially creating external and internal thermal conditions of premises. It was found that the insulation of the structure with a layer of expanded polystyrene PSB-15, 100 mm thick, reduces heat losses through the wall panel by almost half. An algorithm for controlling the heat release process was developed, considering the internal heat capacity of the building. Compared to the "linear" dependence, this allows more accurately adjusting the schedule of heat carrier release to the heating system of a public building during the introduction of the alternating mode of its operation. The temperature deviation range is reduced by 4-6 °C, which allowed saving up to 10-12% of the consumed heat energy for the heating needs of the research object, provided that the normalised values of the internal temperature of the premises are maintained. Intermittent operation of the heating system of public buildings, the expediency of which is justified in this study, can be recommended for implementation in the structures of higher educational institutions of Ukraine [ABSTRACT FROM AUTHOR]

The BCT-7800A PLUS VOC online monitor system was employed to measure ambient volatile organic compounds （VOCs） in a typical solvent-using industrial park in Beijing. From January to June 2023, the pollution characteristics, source apportionment, and ozone formation potential（OFP）of VOCs were studied, and the results of a comparative analysis were also discussed between heating and non-heating periods. The results indicated that VOC concentrations from January to June 2023 were （104.21 ± 91.31） μg·m -3 on average. The concentrations of TVOCs under the influence of southerly and northerly winds were （214.18 ± 202.37） μg·m -3 and （197.56 ± 188.3） μg·m -3 , respectively. Alkanes were the species with the highest average concentration and proportion, respectively （45.53 ± 41.43） μg·m -3 . The VOC concentration during the heating period was higher than those during the non-heating period, with values of （111.57 ± 83.96） μg·m -3 and （87.92 ± 75.03） μg·m -3 , respectively. Propane and ethane were the species with the highest average concentration during the heating period. Compared with those in the non-heating period, the average concentrations of three species （propane, ethane, and n-butane） in the top ten species increased during the heating period, with average concentrations increasing by 51.94%, 54.64%, and 26.32%, respectively. The source apportionment results based on the positive matrix factorization （PMF） model indicated that the major sources of VOCs in the park during the monitoring period were printing emission sources （4.95%）, oil and gas evaporation sources （9.52%）, fuel combustion sources （15.44%）, traffic emissions sources （18.97%）, electronic equipment manufacturing （24.59%）, and industrial painting sources （26.52%）. Therefore, industrial painting sources, electronic equipment manufacturing sources, and traffic emissions sources were the emission sources that the park should focus on controlling. Compared with those during non-heating periods； industrial painting, traffic emission, and fuel combustion sources contributed more during the heating period, with VOC concentrations increasing by 15.02%, 16.53%, and 24.98%, respectively. The average OFP of VOCs from May to June during the monitoring period was 198.51 μg·m -3 and OVOCs, olefins, and aromatic hydrocarbons contributed the most to OFP, which were 47.41%, 22.15%, and 18.41%, respectively. The electronic equipment manufacturing source was the largest contributor to the summer OFP of the park and its contribution rate was 30.11%, which should be strengthened in the future.

As large-scale photovoltaic and wind power are integrated into the power grid, new energy power generation has strong randomicity, volatility and anti-peak shaving characteristics. Both the power supply side and the load side of the power grid will have random fluctuations, which brings huge challenges to the safe and stable operation of the power grid. The power grid will need more capacity and more flexible peak shaving resources as the basis for ensuring the smooth and orderly power supply. During the heating period, the thermoelectric units are faced with double pressures of power consumption peak and heating peak, and are forced to further increase and reduce output to meet the requirements of heating. Therefore, carrying out load capacity test on heating units is conducive to finding out the real output range of units and providing data support for power grid departments.

Copyright of Environmental Science & Technology (10036504) is the property of Editorial Board of Environmental Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, direct shear behavior after exposure to high temperatures of epoxy-coated carbon textile-reinforced mortar (TRM) modified with different types of microfibers was investigated. Three primary test parameters were examined: elevated temperature levels (200°, 250°, and 300 °C); different microfiber types (polyvinyl alcohol (PVA) fibers, steel fibers, amorphous metallic (AM) fibers, and hybrid fibers made up of steel and PVA fibers); and heating time periods (2 and 4 h). In total, 88 direct shear test specimens were manufactured and tested. The direct shear tests were performed based on the FIP standard by employing test specimens with a pre-formed notch around the vertical middle plane. From the test results, it was observed that elevated temperatures significantly affected bond performance between the textile reinforcement and the mortar matrix, leading to degradation in shear mechanical properties of the test specimens. Under ambient temperature, the addition of microfibers to the mortar matrix was beneficial to most shear mechanical properties of TRM specimens, compared with TRM specimens without microfibers. However, the benefits of PVA fibers were significantly diminished at elevated temperatures of 200–300 °C, while AM or steel fibers adequately maintained benefits at the same temperatures. Heating periods investigated in this study did not significantly affect the shear behavior of the TRM specimens. In addition, an analytical model to predict the ultimate shear stress of TRM specimens with and without microfibers (steel or AM fibers) was proposed, and the prediction results agree with the experimental results. [ABSTRACT FROM AUTHOR]

Based on the data of the PM2.5 mass concentrations from the monitoring point at the US embassy in Beijing from 2013 to 2017,the characteristics of PM2.5 mass concentration and its correlation with the mass concentrations of NO2 and SO2 in Beijing in the past five years are analyzed.The emphasis is focused on the variation characteristics of PM2.5 after the action on comprehensive control of air pollution implemented in the autumn and winter of 2017,which is aimed at the emission reduction from banning of uncontrolled coal combustion.The results show that the annual average of PM2.5 mass concentration in Beijing has decreased yearly since 2013,and the decreasing range of the annual average in 2017 has reached 50%.Analysis of data in different seasons shows that the PM2.5 mass concentration in winter is the highest,followed by autumn,spring,summer in descending order in 2013 to 2016.However,after the action on comprehensive control of air pollution,it is noticed that the mass concentration of PM2.5 in winter 2017 was lower than that in autumn and spring,approaching the level of summer.In addition,compared with the past years,the mass concentrations of NO2 and SO2 in the air also decreased significantly in winter 2017,in which the decrease of SO2 mass concentration is more obvious.These results show that the emission from burning coals has been effectively controlled after the action on comprehensive control of air pollution.Finally,the correlation analysis shows that the mass concentrations of PM2.5 has a significant positive correlation with those of SO2,indicating that countermeasures for the banning of uncontrolled coal combustion such as "coals replaced by gas" and "coals replaced by electricity" have an obvious effect on reducing the PM2.5 emission.

PM2.5 and PM10 samples were collected from the outdoor environment of five types of cities (provincial central cities, regional central cities, resource-based cities, agricultural cities, and forested cities) situated in Northeast China. Based on bioaccessibility and respiratory deposition fluxes, health risks of PM2.5- and PM10-bound six heavy metals [HM6: Arsenic (As), Chromium (Cr), Cadmium (Cd), Nickel (Ni), Cobalt (Co), and Lead (Pb)] were studied. Cobalt (Co) and Cr were found to be the most abundantly bioaccessible fraction among HM6 after extraction of simulated lung fluids. After inhalation exposure, among HM6, Co mainly contributed 88.39–93.19% to the non-carcinogenic risk, while Cr account for 82.92–93.72% of cancer risk. The estimated daily intake of bioaccessible HM6 in outdoor environment during the heating period was calculated to be 293.11 ± 121.03, 117.08 ± 32.46, 105.57 ± 32.49, 100.35 ± 25.58 and 83.11 ± 17.64 ng/h for provincial central cities, regional central cities, agricultural city, resource-based cities and forested cities, respectively, for local residents. During the heating period of 180 days, non-carcinogenic risks (As, Cr, Cd, Ni, Co) in outdoor environment of 0.5 residence time were below the safety threshold (HQ

The damage to the environment caused by fossil-derived fuels is very high. Each year air pollution causes the death of close to 3 million people. This value is equivalent to 5% of the global annual death rate. In the literature, greenhouse gas emission calculations are made with data officially recorded from annual fuel and electricity consumption in housing on a provincial basis. These calculations do not differentiate energy consumed for heating, hot water or domestic appliances (fridge, air conditioning, washing machines, dishwashers, iron, oven, etc.). This study calculated energy requirements for heating and per person emissions with a new method taking account of different wall types, fuel and insulation material for İzmir province. The carbon dioxide amount released per unit area in the heating period (CDUAHP) and sulfur dioxide released per unit area in the heating period (SDUAHP) were compared according to wall, fuel and insulation material types and without insulation. The effect of optimum insulation thickness (OIT) on the environment and energy was calculated for İzmir. It was determined that with different fuel, isolation material and wall types, energy demand and CDUAHP reductions could reach 76% levels. Two new approaches of carbon dioxide amount per person in the heating period (CDPPHP) and sulfur dioxide amount per person in the heating period (SDPPHP) were developed. For 1TEIW with XPS according to OIT and coal as fuel, the CDPPHP was 836 kg/person year, while the SDPPHP for an uninsulated apartment was 7196 kg/person heating period, with 1727 kg person/heating period calculated according to OIT. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ecology & Rural Environment is the property of Journal of Ecology & Rural Environment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Nitrous acid (HONO) is of great interest due to its contribution to hydroxyl (OH) radicals by self-photolysis. Nowadays, machine learning (ML) algorithms are good at capturing complicated non-linear relationships between predictors and dependent variables. Here, using the whole year of 2018 of observed HONO and related pollutant data at an urban site in Beijing, an ML-RF (random forest) model is carried out to predict HONO concentrations and explore the main factors influencing HONO formation mechanisms. ML-RF models show satisfactory performance during the heating, non-heating and whole year periods with R values of 0.95, 0.96 and 0.95, respectively. Primary emissions and diffusion have an obvious influence on ambient HONO during the heating period, while chemical formation processes such as NO 2 heterogeneous reaction and photolysis of nitrate are important for HONO during the non-heating period with higher RH and stronger solar intensity. O 3 and NH 3 are the most important variables for HONO in both periods, indicating the close relationship of HONO with atmospheric oxidation and the important role of NH 3 in HONO formation processes. Although there are deviations due to some variability in HONO formation mechanisms between years, ML-RF models based on 2018 data are able to roughly predict HONO for three periods in 2017 and 2021. Overall, machine learning with limited meteorological and pollutant parameters offers great advantages in HONO prediction, and it can also provide some clues to improve the chemical mechanisms of HONO by finding related variables of ambient HONO. [Display omitted] • Machine learning predicted HONO shows satisfactory performance in 2018. • O 3 and NH 3 are the most important HONO predictors. • Main HONO sources are different between heating and non-heating periods. • Machine learning model is feasible to predict HONO across years. [ABSTRACT FROM AUTHOR]

The distribution characteristics and sources of gaseous elemental mercury (GEM) on haze and non-haze days are still not clear. During the winter heating period in 2017, the GEM concentrations in Qingdao were studied for their differences, sources, and pollution characteristics on haze and non-haze days. The GEM concentration on haze days (2.81 ± 2.23 ng/m3) was higher than that on non-haze days (1.90 ± 1.21 ng/m3) and the difference was significant (p < 0.01) during the period of artificial heating. The average concentration of GEM was 2.27 ng/m3 in the heating period, but lower than that before heating (3.30 ng/m3). However, the mercury to carbon monoxide ratio (GEM/CO) on haze days was lower than that on non-haze days. The ratio of GEM/CO in this study was lower than that in other studies reported from China. There was a positive correlation between the GEM/CO ratio and the air temperature (p < 0.01), suggesting that the mercury released from the Earth's surface was important. The environmental policies of China also contributed to decrease of the GEM/CO ratio. Similar diurnal patterns appeared on both haze and non-haze days, with one GEM peak at 14:00–15:00. This pattern was different from the bimodal pattern of other atmospheric pollutants in the morning and evening rush hours and was controlled by GEM from the Earth's surface (mostly re-emission of legacy Hg) whether on haze or non-haze days. Principal component analysis showed that the contribution of GEM directly from anthropogenic sources was relatively small. The main influencing factor on haze days was air temperature. GEM concentrations showed large spatial differences in air masses from different places. The GEM concentration in air masses from southern and the western Shandong Province was higher than from the north on haze days. Unlabelled Image • GEM concentration on haze days was higher than that on non-haze days. • GEM/CO ratio on haze days was lower than that on non-haze days. • GEM diurnal variation on haze days was controlled by solar radiation. • Air masses from the south had higher GEM and GEM/CO ratio than that from the north. [ABSTRACT FROM AUTHOR]

Since the implementation of the Action Plan for Air Pollution Prevention and Control, all regions of China have steadily promoted the prevention and control of air pollution and achieved results continuously. However, the atmospheric environment in key areas such as Beijing - Tianjin - Hebei region, the Yangtze River Delta region, and Fenwei Plain is still severe, and especially during the heating period heavy pollution occurs frequently, which has become the focus and difficulty of improving the quality of the atmospheric environment and is also the weakest link of China's air pollution control at present. How to alleviate air pollution, how to win the battle of pollution prevention and control, how to hold the fruits of the blue sky defense war, energy consumption is key. [ABSTRACT FROM AUTHOR]

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Abstract PM 2.5 particles were collected to study the distribution, accumulation and health risk assessment of metal pollutants. The concentrations of 11 kinds of metal elements in PM 2.5 during heating period and non-heating period were analyzed. Based on the American health risk assessment model as well as the human exposure parameters in China, the human health risk was assessed. The concentrations of metal components in PM 2.5 during the heating period were, in descending order, Pb, Mn, Cr, As, Sb, Se, Ni, Cd, Tl, Hg, and Be, while during the non-heating period, they were basically in the same order, except Cd and Ni, as the concentration of the former was a little higher than that of the latter. The concentrations of As, Cd, Hg, Ni, Se, and Tl were quite different in the heating period and non-heating period. The non-carcinogenic risks caused by metal elements were lower than the minimum acceptance 10−6 per year during both the heating period and non-heating period. The non-carcinogenic results of a descending order were Pb, Mn, Sb, Tl, Se, and Hg. The carcinogenic risks of a descending order were Cr, As, Cd, Ni, and Be. The risks of As and Cr to children were over 10−6. Hence, As and Cr should be considered as priorities. Highlights • The pollution characteristics of 11 kinds of metal pollutants were analyzed. • The concentrations were significant differences between heating period and non-heating period. • Higher non-carcinogenic and carcinogenic risks were shown for children during heating period. • Cr and As had higher carcinogenic risks for people. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

China's aging population is growing rapidly. To date, there have been few literatures concerning indoor environment of private houses with older people. This study fully investigated indoor environment in 10 houses (5 urban and 5 rural houses) with older people during heating season in Beijing, China. Each house was assessed for temperature, relative humidity, CO 2 , PM 2.5 , CO, NO x , formaldehydes, acetaldehyde, VOCs, SVOCs and fungi. Results indicated older people in urban houses experienced a steadier and warmer thermal environment than those in rural houses, due to the difference of heating devices between urban and rural houses. Indoor CO 2 levels mainly increased up to 1000 ppm in the bedroom during sleeping time. For rural houses, indoor fuel combustion contributed to an extremely high PM 2.5 and CO level. Formaldehyde, acetaldehyde, toluene, ethylbenzene and xylenes levels in most houses were lower than the limit values. However, the integrated influence of these compounds was unnegligible. TVOC concentrations in four measured houses exceeded the reference value of 600 µg/m 3 . The most frequent fungi was Cladosporium spp. (90%), followed by Penicillium spp . (70%) and Aspergillus spp. (60%). The fungal levels in rural houses were higher than urban houses. These results will be beneficial to improve housing environmental quality for older people in China. [ABSTRACT FROM AUTHOR]

This study intends to investigate indoor thermal environment in homes with elderly people during heating season in Beijing, China. The investigation was performed from December 2016 to February 2017, involving both urban and rural houses. Heating equipment, indoor clothing and thermal sensation of the elderly, and indoor physical parameters were analyzed through subjective surveys and objective measurements. Results show that different types of heating systems/devices are used in urban and rural houses. Overall, the heating duration of rural houses is longer than that of urban houses in winter. In terms of indoor air temperature, urban elderly people experienced warmer and steadier thermal environments than rural elderly people. During the investigation, the average air temperature in living rooms/elderly people's bedrooms of urban houses was 21.9 ± 2.2 °C/21.5 ± 2.8 °C, significantly higher than 16.1 ± 3.5 °C/14.6 ± 3.3 °C of rural houses. Additionally, rural elderly people usually encountered a large temperature step between indoors and outdoors, due to frequent exit and entry. Despite of relatively low air temperatures in rural houses, the elderly reported that the indoor thermal environment was acceptable, since the elderly in rural areas wear thicker clothes indoors in winter. This also indicated the acceptable temperature for elderly people in rural areas was lower than that for elderly people in urban areas. It is noted that the acceptable temperature may not satisfy long-term physical health requirements of the elderly. More studies are needed to determine reasonable temperature for both thermal comfort and health of the elderly. [ABSTRACT FROM AUTHOR]

Based on the 12-hour PM 2.5 samples collected in an urban site of Beijing, sixteen PM 2.5 -bound Polycyclic Aromatic Hydrocarbons (PAHs) were measured to investigate the characteristics and potential source regions of particulate PAHs in Beijing. The study period included the summer period in July–August 2014, the APEC source control period during the Asia-Pacific Economic Cooperation (APEC) meeting in the first half of November 2014, and the heating period in the second half of November 2014. Compared to PM 2.5 , sum of 16 PM 2.5 -bound PAHs exhibited more significant seasonal variation with the winter concentration largely exceeding the summer concentration. Temperature appeared to be the most crucial meteorological factor during the summer and heating periods, while PM 2.5 -bound PAHs showed stronger correlation with relative humidity and wind speed during the APEC source control period. Residential heating significantly increased the concentrations of higher-ring-number (≥4) PAHs measured in PM 2.5 fraction. Potential source contribution function (PSCF) and concentration weighted trajectory (CWT) analysis as well as the (3 + 4) ring/(5 + 6) ring PAH ratio analysis revealed the seasonal difference in the potential source area of PM 2.5 -bound PAHs in Beijing. Southern Hebei was the most likely potential source area in the cold season. Using black carbon (BC) and carbon monoxide (CO) as the PAH tracers, regional residential, transportation and industry emissions all contributed to the PAH pollution in Beijing. [ABSTRACT FROM AUTHOR]

In China, there are 1.848 million postgraduate students at school by 2014. They spend more than half of the time doing scientific research in research student offices. In order to understand indoor air quality (IAQ) in these offices, indoor climate and carbon dioxide (CO 2 ) concentration were investigated in a typical naturally ventilated postgraduate student study room in a university of China during heating season. Results demonstrated that, due to high occupancy rates, indoor CO 2 level often exceeded 1000 ppm, even reaching a peak value of 3000 ppm. During occupied time, average of 77.6% of measured CO 2 data each day exceeded the threshold. The longest duration of exposure to CO 2 concentration more than 1000 ppm had an average of 3.68 h per person per day. These results implied that the research student office required attention in meeting acceptable IAQ. [ABSTRACT FROM AUTHOR]

Indoor air humidity (IAH) is one of the most important factors in the determination of in-door environmental conditions and thermal comfort. However, during the heating period in cold climates it has been reported that indoor relative humidity is often lower than 30%. This paper focused on indoor low air humidity and explored the solution to solve the issue based on a simple experiment. It was found that natural evaporation of water from the vertically wetted fiber fabric could effectively improve IAH. Both evaporation rate and evaporation quantity of water from wetted porous fiber fabric had significant influences on attainable maximum value of IAH. In addition, it was worth noting that the entire regulating process did not need to consume energy. [ABSTRACT FROM AUTHOR]

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In order to investigate monthly variations and chemical compositions of atmospheric particulates during the heating period, PMi and PM2.5particulates were sampled and analyzed, including the characteristics of size distributions and mass concentrations of metal elements and ions. In addition, the sources of metal elements in PM1 were analyzed by the Enrichment Factor (EF). The results showed that the mass concentrations of As, Ba, Cr, Cu, Zn, Mn, Ni, Pb, Sr, and Ti ranged from 0.018 to 0.8 μg/m3, while Ni was not detected in December. The mass concentrations of AI, Ca, Fe, K, Mg, and Na ranged from 0.4 to 12.5 μg/m3, in which the concentrations of Na and Ca were much liiglici-willi the values of 9.091 and 12.131 μg/m3, respectively. The characteristics of size distributions showed that the metal elements accounted for 56%~97% of the total mass of PMi, which indicated that the metal elements were mainly enriched in ultrafine particles. The variations of ions in PM1 and PM2.5 were the same. The total mass concentrations of 9 ions in PM1 and PM1.swere from 30.5 μg/m3to 60.9 μg/m3 and from 38.7 μg/m3to 78.0 μg/m3 respectively during the heating period. The mass concentrations of SO42" and NO3- were higher than other ions, and that of Mg2+ and I were lower between 0.1 μg/m3 and 0.95 μg/m3. Enrichment factor analysis suggested that the EF values of the metal elements except Mn and F- were more than 10, and they were primarily emitted from anthropogenic sources including coal combustion, burning straw, automobile exhaust and fireworks. The EF values of As, Pb were about 1000 which were mainly from fossil fuel combustion. It also showed that the combustion of coal and other fossil fuels during the heating period was the main reason for the increase of some heavy metal elements. [ABSTRACT FROM AUTHOR]

ABSTRACT As the coolest region in China, Northeast China has long and severe winters and is a main region for the use of central heating. Accurately predicting the heating energy consumption in Northeast China is very important for energy management and planning. Based on daily mean temperature data from 70 weather stations, this study investigated the spatiotemporal changes in the starting date for heating ( HS), the end date for heating ( HE), and the length ( HL) and the heating degree days ( HDD) of the heating period in Northeast China. Over Northeast China, regional averaged HS has become later by 0.77 days decade−1 and HE has become earlier by 1.19 days decade−1 during 1960-2011. Accordingly, regional averaged HL and HDD decreased significantly by 1.97 days decade−1 and 66.28 °C decade−1 respectively; this implies a decreasing demand for heating throughout the region. Spatially, the temporal trends of each heating variable varied in different locations. The spatial patterning of the HL trend was unlike that of the HDD trend due to different responses of HL and HDD to climate change. Temperature increase seems to have larger impacts on HL in warm south localities but more obvious effects on HDD in cold north localities of Northeast China. These different sensitivities of HL and HDD to temperature change should be considered when attempts are made to predict heating energy consumption in Northeast China in a changing climate. [ABSTRACT FROM AUTHOR]

Understanding the impact of temperature fluctuations on air quality and public health has gained popularity among environmental and epidemiological researchers. Potentially, increase and decrease in temperature between neighboring days have increased the environmental and health risk worldwide. Based on ordinary least-squares method, this paper aims to examine the impact of temperature fluctuations on air quality index (AQI) and respiratory health outcomes (RHOs) during 2008-2012 in Beijing. Our results show that a drop of more than 3 °C results in the increased impact on AQI and RHO in the heating period. At the same time, a raise of more than 3 °C results in the similar increased impact on AQI in the whole study period and heating period. Furthermore, for a raise of more than 3 °C, a larger impact on RHO is observed in the heating period compared with the whole study period. Additionally, an increase in temperature also results in the increased influence of health risk on females during the heating period. Our results suggest that the air quality and public health in Beijing are significantly influenced by decrease and increase in temperature in the heating period. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) and its oxygenated derivatives (OPAHs) are toxins in PM 2.5 . Little information has been known for their transformation in the ambient airs. In this study, PM 2.5 samples were collected at 19 sampling sites in Xi’an, China during the heating period, which is classified into: urban residential, university, commercial area, suburban region, and industry. Organic compounds including PAHs, OPAHs, hopanes and cholestanes were quantified. The average of total quantified PAHs and OPAHs concentrations were 196.5 ng/m 3 and 29.4 ng/m 3 , respectively, which were consistent with other northern cities in China. Statistical analyses showed that there were significant differences on the distributions of PAHs between urban and suburban regions. The industry also had distinguishable profiles compared with urban residential and commercial area for OPAHs. The greater diversity of OPAHs than PAHs might be due to different primary emission sources and transformation and degradation pathways. The ratios of OPAHs to the corresponding parent PAHs, including 9-fluorenone/fluorene, anthraquinone/anthracene, benz[ a ]anthracene-7,12-dione/benzo[ a ]anthracene were 6.2, 12.7, and 1.4, respectively, which were much higher than those for the fresh emissions from coal combustion and biomass burning. These prove the importance of secondary formation and transformation of OPAHs in the ambient airs. Biomarkers such as retene, cyclopenta[CD]pyrene and αα-homohopane were characterized for the source apportionment. With Positive Matrix Factorization (PMF) model analysis, biomass burning was recognized as the most dominant pollution sources for PAHs during the heading period, which accounted for a contribution of 37.1%. Vehicle emission (22.8%) and coal combustion (22.6%) were also contributors in Xi’an. [ABSTRACT FROM AUTHOR]

The diurnal variations of the water soluble organic and inorganic components as well as six selected metals in PM 2.5 around the heating periods of 2013 and 2014 in Beijing were analyzed in this study to investigate the contributions of secondary aerosols and primary pollutants to PM 2.5 and the effects of domestic heating and mitigation measures. The before-heating sampling period in 2014 (from Nov. 1st to Nov. 15th) was characterized with reinforced short-term mitigation measures for the 2014 Asia–Pacific Economic Cooperation (APEC) meeting. As a result, the average mass concentrations of PM 2.5 and most of the measured species except for Cu, Al, and Ca 2+ were greatly reduced during the APEC meeting period. The domestic heating activity alone resulted in a 17.7% increase of PM 2.5 in 2013, exerting lesser effects on the increase of PM 2.5 than before. Water soluble organic carbon was the most abundant water soluble species in PM 2.5 , followed by NO 3 − , SO 4 2 − , and NH 4 + . According to the PMF model calculation, secondary aerosols, coal combustion, biomass/waste burning, traffic related pollution, long-range transport, and fugitive soil and sand dust were identified as the main sources of PM 2.5 in Beijing, among which secondary formation of aerosols was the dominant source of PM 2.5 during the non-APEC period while biomass/waste burning dominated during the APEC period. As a timely feedback on the effects of the mitigation measures adopted by the government, the results of this study provide knowledge necessary for a sustainable urban management. [ABSTRACT FROM AUTHOR]

By this study, it was aimed to define a testing and calculation model for thermal comfort assessment of a bus HVAC design and to compare effects of changing parameters on passenger's thermal comfort. For this purpose, a combined theoretical and experimental work during heating period inside a coach was carried out. The bus was left under 20 °C for more than 7 h within a climatic chamber and all heat sources were started at the beginning of a standard test. To investigate effects of fast transient conditions on passengers' physiology and thermal comfort, temperatures, air humidity and air velocities were measured. Human body was considered as one complete piece composed of core and skin compartments and the Transient Energy Balance Model developed by Gagge et al. in 1971 was used to calculate changes in thermal parameters between passenger bodies and bus interior environment. Depending on the given initial and environmental conditions, the graphs of passengers Thermal Sensation and Thermal Discomfort Level were found. At the end, a general mathematical model supported with a related experimental procedure was developed for the use of automotive HVAC engineers and scientists working on thermal comfort as a human dimension. [ABSTRACT FROM AUTHOR]