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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]

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 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]

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.

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

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]

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]

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]

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]

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]

A comprehensive measurement program was undertaken in winter 2009 in a large urban city (Ji'nan) in North China Plain (NCP). The average concentrations of NO, NO2, NOx, NOy, SO2, O3, CO, PM2.5 and BC during the program were 63.9±65.1ppb, 45.2±16.9ppb, 106.6±77.8ppb, 120.7±77.4ppb, 54.3±25.8ppb, 6.3±6.0ppb, 2138.3±1512.8ppb, 171.3±83.9μg/m3 and 9.8±6.9μg/m3, respectively. Two severe haze episodes were observed. All species, except O3, had elevated concentrations on the episodes compared with those on non-hazy days due to accumulation of pollutants. Diurnal variations of species concentrations and correlation analysis suggested that emissions from vehicles and coal combustion (from power plants, industry and domestic heating) are the main sources. Air mass on Episode 1 was predominately influenced by coal combustion, while pollution was characterized by the vehicular emissions on Episode 2. In contrast, on non-hazy days, pollutants were mainly from the mixing of local coal-fired and vehicular exhaust emissions. These distinct characteristics were further supported by higher ratios of CO to NOy and SO2 to NOy on Episode 1 (25.46ppb/ppb and 0.51ppb/ppb) compared to Episode 2 (15.55ppb/ppb and 0.36ppb/ppb) and non-hazy days (18.15ppb/ppb and 0.45ppb/ppb). Multiple linear regression analysis was applied to the concentrations of NOy, SO2 and CO in the observation and empirical equations were obtained for the NOy concentration. Based on the equations, the relative contributions from mobile (i.e. vehicular exhaust) and point sources (i.e. coal combustion) to NOy were estimated to be 68.2% and 38.6%, respectively, demonstrating that even in the demanding period of domestic heating in NCP, vehicular emissions in a large urban city contribute more to NOy than coal combustion emissions. This also implies that vehicular emissions, featured with high NOx, become a dominant source of pollution, highlighting the recent finding of long-term increase of NO2 in the NCP region by satellite observation (Richter et al., 2005). [ABSTRACT FROM AUTHOR]

Abstract: This paper describes a combined theoretical and experimental study of thermal comfort during the heating period inside an automobile. To investigate the effects of thermal conditions on the human physiology and thermal comfort during the heating period, temperature, humidity and air velocity were measured at a number of points inside the automobile, so thermal conditions were accurately determined. The human body was divided into 16 sedentary segments, and the change of temperature was observed both experimentally and theoretically. During transient conditions of the heating period, heat and mass transfer between the human body and the interior environment of an automobile were simulated by a computational model, and predictions were compared with the measured data. It is shown that there is a good agreement between the model predictions and experimental results. By means of the present model, the effects of the fast transient conditions of the heating period on the sensible and latent heat transfer from the body, body segments skin temperatures and thermal sensation were investigated in detail. [Copyright &y& Elsevier]

Secondary atmospheric pollutants are an important component of the particles found in Urumqi city, China, Further, secondary inorganic aerosols, in particular, increase significantly during the winter heating period. In this study, samples collected from October 2017 to August 2018 from Urumqi were analyzed. Results showed that the average concentration of water-soluble inorganic ions (WSIs) in the heating period (86.9 ± 31.1 μg·m−3) was significantly higher than that in the non-heating period (14.1 ± 8.67 μg·m−3). SNA (SO 4 2−, NO 3 −, NH 4 +) accounted for 90.7% of the total WSIs (TWSIs) in the heating period. Simulations revealed that the in situ pH (3.1) was higher in the heating period than that in non-heating period (0.66) when they were calculated by the aerosol thermodynamic model. The particles were found to be acidity during the entire period. The liquid water content of the particulates (LWC) was found to higher in the heating period (55.5 ± 51.8 μg·m−3) than the non-heating period (21.3 ± 40.3 μg·m−3). The average nitrogen oxidation rate (NOR) and sulfur oxidation rate (SOR) were 0.16 and 0.36, respectively, indicating a significant secondary formation of nitrate and sulfate in the atmosphere of Urumqi. Further analysis indicated that sulfate was significantly affected by the LWC and acidity of the particulates; nitrate was produced under ammonia-rich conditions in Urumqi, and the LWC facilitated the production of nitrate. This study provides information about the formation of secondary sulfate and nitrate aerosols during different periods in suburban Urumqi. • During the heating period, high concentrations of SO 4 2− and NO 3 − cannot lead to increase of the acidity of aerosols. • More crustal sources will affect the calculation results of the aerosol thermodynamic model. • Particulate liquid water plays a key role in formation of secondary aerosols in heating period. [ABSTRACT FROM AUTHOR]

PM 2.5 and PM 10 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 PM 2.5 - and PM 10 -bound six heavy metals [HM 6 : 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 HM 6 after extraction of simulated lung fluids. After inhalation exposure, among HM 6, 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 HM 6 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 < 1). Cancer risks for Cr and Co were above 10−5 in the five types of cities, but in the assumable range (< 10−4). Our study highlighted the wide range of measures needed to cut airborne particles pollution to safer levels. [Display omitted] • Bioaccessibility of airborne particles-bound heavy metals in five types of cities were measured. • Cr and Co were found in the most bioaccessible fractions in airborne particles. • Strong relationships between inhalation exposure and characteristics of city. • Higher levels of carcinogenic and non-carcinogenic risk were estimated in provincial central city. [ABSTRACT FROM AUTHOR]

In the context of the mismatch between the potential in biomass energy and energy demand, proper space allocation and energy flow are necessary to improve the utilization rate of biomass energy, but the spatial distribution of heating demand has not been fully studied. This paper takes 50 cities/counties in the UTC+0800 time zone of the centralized winter heating zone in China and investigates the effects of geographical latitude on the per-capita raw material consumption by biomass combined heat and power plants (biomass CHP plants). Per-capita energy consumption is determined by electricity and heating consumption. The per-capita raw material consumption by biomass CHP plants during heating and non-heating periods is calculated by combining the average calorific value of each province with thermal efficiency. A regression model was constructed for latitude and per-capita raw material consumption by biomass CHP plants. The resulting curve exhibited an inverse S-shape during the heating period, with a positive correlation, but an insignificant correlation during the non-heating period. The study area can be divided into a high-impact area (regions to the south of 37°N and north of 45°N) and a low-impact area (regions between 37°N and 45°N). The initial investment process for the high-impact area should use scale and the heat-to-power ratio for planning biomass CHP plants according to geographical area and the design energy flow based on latitude to improve the self-sufficiency and energy efficiency of the area. Image 1 • Latitude can affect material consumption of biomass combined heat and power plants. • Per capita heating consumption has strong latitude correlation. • Per capita electricity consumption does not show clear latitude dependence. • Shorten some cities' heating period can reduce energy waste without lowing standard. [ABSTRACT FROM AUTHOR]

To explore the impact of the "Coal to Gas" project on air pollution around Beijing, the pollution observation data during the heating periods (from Nov.15 to Mar.15) of 2017 and 2018 at Xianghe Observatory in Langfang, Hebei Province of China, were analyzed in combination with meteorological data and fuel incremental statistics. According to this project, Xianghe County reduced coal consumption and increased gas consumption by 26.71 million cubic meters in 2018. Our observations showed that some of the air pollutants in the Langfang area were effectively improved by changing fuel from coal to natural gas, including SO 2 , PM 2.5 , PM 10 and CO; the average concentrations of them in the heating period of 2018 significantly dropped compared with those in 2017, with decreases of 46.5%, 13.1%, 21.0% and 10.5%, respectively. However, the concentration of nitrogen oxides (NO X = NO+NO 2) increased significantly. The average NO X concentration increased from 78.7 to 116.1 μg/m3, while the concentrations of NO 2 and NO increased by 24.8% and 76.8%, respectively. Such a significant increase in NO X will bring about changes in the atmospheric oxidation process and influence human health. Changes in meteorological elements were not the main cause of elevated NO X because the total averaged PLAM changing rate and the PLAM changing rates in most of the months indicated a more favorable condition for the diffusion of pollutants. Through the comparison of daily changes in various pollutants during holidays and working days, the impact of motor vehicle emissions on the increase in NO X was essentially ruled out. Compared with that in the heating period of 2017, the significantly higher NO X in 2018 mainly appeared in early morning, which was consistent with the main heating period, and the differences in NO X between holidays and working days were found to be related to sectional heating. At the same time, it was found that the average concentration of NO 2 from Nov. 2018 to Mar. 2019 increased in all 12 cities in the Beijing-Tianjin-Hebei region compared with the same period of the previous year, and more than half of the cities had similar variation characteristics of NO 2 than that of Langfang. Heating gas was the main factor causing the increase in NO X concentration in Langfang city during the heating period in 2018. Excluding the impact of meteorological conditions, the "Coal to Gas" project brought about 51.8% increase in NO X in the southeast area of Beijing during the heating period of 2018, as well as 8.8%, 16.7%, 42.2% and 10.5% decrease of PM 2.5 , PM 10 , SO 2 and CO, respectively. Unlabelled Image • We explored the impact of the "Coal to Gas" project on NO X around Beijing for the first time. • Sharply rise of NO X in Xianghe was spotted in 2018 heating period, while PM 2.5 , SO 2 and CO decreased. • Higher NO X appeared in the main heating period in early morning. • The discrepancies of NO X between holidays and working were related to sectional heating. • The project triggered 51.8% increase in NO X in Langfang, but PM 2.5 , SO 2 and CO decreased 8.8%, 42.2% and 10.5%, separately. [ABSTRACT FROM AUTHOR]

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., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

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., (Copyright © 2017 Elsevier Ltd. All rights reserved.)