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[Display omitted] Waste-to-Energy (WtE) technology is the most effective solution for managing non-recyclable wastes through mass burning and energy recovery. Owing to the significant volumes of plastics in China's industrial solid wastes (ISW), a large amount of greenhouse gases (GHG) is generated during the incineration process. Therefore, monitoring GHG emissions from WtE facilities is essential. Owing to the lack of suitable accounting models and characterized fossil carbon fraction (FCF) data, current studies use default values provided by the Intergovernmental Panel on Climate Change's (IPCC), which increases calculation inaccuracies. Therefore, this study established an improved method to accurately account for carbon emissions during solid waste incineration by firstly using radiocarbon dating by accelerator mass spectrometry (AMS) technique to determine the FCF of the solid waste components in China. Monte Carlo analysis was employed to perform the sensitivity analysis, and the results indicated that there was a significant deviation between the measured value and IPCC's default values of FCF, 3.2, 32.48, 93.39, 93.76, 90.49, and 93.8 % for paper, cotton, synthetic textiles, artificial rubber, artificial leather, and plastics, respectively. By replacing coal with ISW in a 2 × 110 t/h circulating fluidized bed boilers, 9.251 × 104 t CO 2 -eq emissions were reduced, and the carbon emission factor reached 0.56 t CO 2 -eq/t waste. This study complements the research gap fossil carbon data of wastes in the IPCC guidelines and provides a more accurate and effective way to calculate carbon emissions during ISW incineration treatment. [ABSTRACT FROM AUTHOR]

It is important to know how much of the increased atmospheric CO2 is derived from fossil fuel emissions. Here, we review the progress in atmospheric fossil fuel CO2 (CO2ff) tracing over recent years by measurement of Δ14C in Chinese cities. In this paper we make progress by expanding the analysis from some locations to more regional views, by combining observations with modeling, and by making a preliminary comparison of observation-derived CO2ff with inventory-derived CO2ff. We have obtained a general picture of Chinese urban CO2ff and characteristics of its spatio-temporal variations at different scale, and identified the corresponding influencing factors. Interestingly, we found that the weekend effect of CO2ff was less evident in Chinese cities. In addition, we observed simultaneous variations in CO2ff and PM2.5 in a winter haze event in Beijing and a simultaneous decrease in annual averages of CO2ff and PM2.5 in Xi'an based on multi-year (2011–2016) Δ14CO2 monitoring. We found that local coal combustion was the main source of CO2ff in Xi'an, which is located in the Guanzhong basin, by applying a WRF-Chem model and looking at δ13C signatures. Thus, reduction of coal consumption is a crucial target for carbon emissions reduction in China. [ABSTRACT FROM AUTHOR]

Discriminating the provenance of fine-grained sediments is crucial for reconstructing paleogeography, sedimentary processes, and paleoclimate. In this paper, we investigate the South Bohai Coast to better understand source-to-sink systems in East Asia. This region is influenced by both distant sources such as the large-scale Yellow River and small local river sources flowing from the Luzhong Mountain area. Two Holocene sedimentary cores, dated using optically stimulated luminescence (OSL) and accelerator mass spectrometry (AMS) 14C chronology, were used to investigate the provenance of the fine-grained sediments over the last 7 kyrs. Clay mineralogy and relevant non-linear modeling were employed for provenance discrimination. The results show that the fine-grained sediments along the South Bohai Coast were mainly derived from the Yellow River during the periods of 7.0–5.4 ka and 4.5–2.6 ka, respectively, while the input from the Luzhong Mountain-derived rivers was greater during 5.4–4.5 ka and 2.6–0.2 ka, respectively. Fluvial activities and marine-terrestrial interaction driven by climate factors such as East Asian winter monsoon, temperature, and precipitation in river basins, dominantly influenced the provenance of fine-grained sediments from 7.0 to 2.6 ka. Anthropogenic impact on provenance increased after 2.6 ka. The chronology of the two cores showed extremely rapid sedimentation rate transitions at 5.2 ka and 1.5 ka, respectively, very likely attributed to anthropogenic-induced rapid progradation. Our study provides a model for better understanding the paleoenvironmental and paleogeographic evolution of a coastal area where multiple sources exist. • Anthropogenically high sedimentation rate in the South Bohai Coast in late Holocene. • Provenance discrimination of the fine-grained sediments in the South Bohai Coast since the mid-Holocene. • The major source of the fine-grained sediments in the South Bohai Coast changed episodically. [ABSTRACT FROM AUTHOR]

Since the first AMS research work was carried out in China, nearly 40 years has past. In this paper, the AMS instrument techniques in world and China were introduced. Particularly, the research works on AMS instrument techniques were introduced in detail which included the super ionization mass spectrometry at the China Institute of Atomic Energy and Qixian Nuclear （Beijing） Science and Technology Company. [ABSTRACT FROM AUTHOR]

According to the characteristics of the LEO space particles radiation environment of China's Fengyun No. 3 (FY-3) polar-orbiting meteorological satellites, in order to monitor the characteristics, and space–time distribution of charged particle radiation in the orbit space, it is proposed to install a three-directional high-energy particle detector (HEPD) in the three vertical orthogonal directions of FY-3E, so as to carry out the energy spectrum and flux observation of high-energy protons and electrons in the three directions of the satellite, namely, −X, +Y, and −Z. The on-orbit detection data acquired by these payloads can be used for space environment modeling and solar-terrestrial physics research, and provide data sources for operational space environment weather warning and forecasting. Through the ground accelerator calibration experiment and simulation analysis of the three-directional HEPDs developed in the flight model phase, the experimental results show that all the HEPDs' measured values meet the requirements for technical indexes, such as the detection energy range (high-energy protons: 3–300 MeV; high-energy electrons: 0.15–5.7 MeV), energy span accuracy (<15%), flux accuracy (<15%), and sensitivity (<5% (ΔN/N)). [ABSTRACT FROM AUTHOR]

Plant materials used in the construction of segments and beacon towers of the ancient Great Wall in northwestern China contain untapped potential for revealing local paleoclimatic and environmental conditions. For the first time, we characterize the molecular preservation and stable carbon and nitrogen isotope compositions of AMS-dated common reeds (Phragmites) collected from ancient Great Wall fascines in today's Gansu and Xinjiang using a combination of chromatographic techniques and isotope analyses. Our molecular data, along with Scanning Electron Microscopy, demonstrate excellent preservation of these ancient reeds, which were harvested from nearby habitats during periods of significant expansion of Imperial China when climate conditions sustained sizeable oases in the region. Stable isotope data capture differential rates of environmental change along the eastern margin of the Tarim Basin since the Han Dynasty (170 BC), implying that significant surface-water hydrological changes occurred only after the Song Dynasty (1160 AD) due to regional climate change. This study reveals the wealth of environmental and climate information obtainable from these site-specific organic building materials and establishes the foundation for further applications of advanced molecular, biochemical, and isotopic technologies to study these common and widely-distributed organic archaeological materials. [ABSTRACT FROM AUTHOR]

Natural and social environment changes have played important roles in social evolution in different times and spaces. Geopolitical change, in particular, might play a decisive role in social evolution during historical periods. The eastern Tienshan Mountains was a transportation hub for communication between the East and the West, where the natural environment is fragile and the social environment has been complex during the historical period. However, geopolitical change and its impact on local social development remain unclear due to fragmented historical records and limited studies. This study investigates the spatiotemporal variations of military facilities in the Hami region, and compares historical documents and archaeological and paleoclimate records to discuss geopolitical changes and social evolution during the historical period in the eastern Tienshan Mountains. A total of 84 visible organic remains from 38 historic beacon towers and 8 dak sites in the Hami region of the eastern Xinjiang Uygur Autonomous Region, northwestern China, were collected and the radiocarbon (14C) dates of these ruins were systematically determined with accelerator mass spectrometry. The dating results show that these sites were mainly built during two major periods: ca. 600–900 cal AD and ca. 1600–1950 cal AD, which roughly correspond to the Tang Dynasty (618–907 AD) and the Qing Dynasty (1636–1912 AD) in ancient China. Human settlement intensity was high during the Han, Tang, and Qing dynasties, and relatively low when the area was controlled by nomadic or local regimes. This suggests that agricultural empires and nomadic/local regimes adopted different strategies for regional management. Climate change might have affected geopolitical patterns, which, in turn, profoundly influenced human activities and social evolution in the eastern Tienshan Mountains over the last two millennia. This study systematically reveals the spatiotemporal variations of beacon towers and dak ruins in the region through a large number of reliable direct 14C dating, it reveals the remarkable differences in human activities in the eastern Tienshan Mountains under different administrations, and it explores the influence of geopolitics and climate change on social evolution in the eastern Tienshan Mountains from a multidisciplinary perspective. [ABSTRACT FROM AUTHOR]

Soil erosion has become more serious in semiarid areas around the world. However, the discrimination of the impact of concurrent climate change and human activity on soil erosion in a particular study area remains a challenge. Check dams are important engineering measures to prevent soil erosion on the Chinese Loess Plateau, and the dam sediments, as the product of soil erosion, are related to both climate change and human activities in a small watershed. The present study selected a check dams sediment profile in the upper Jinghe Basin on the Chinese Loess Plateau as a case study. Based on AMS 14C dating and 137Cs measurement, we established the soil erosion timescale and employed multiple methods including magnetic susceptibility, particle size, and minerals to trace the soil erosion history. We compared them with a local hydrometeorological record in the Jinghe Basin to explore the relationship between soil erosion and human activities. AMS 14C and 137Cs results indicated that the profile was deposited since 1953. The results of magnetic susceptibility, particle size, and minerals revealed 3 soil erosion phases during the last 60 years. Soil erosion in this region is not only related to precipitation changes, but also closely related to human activities. Prior to the Reform and Opening-up in China in 1978, climatic change played a leading role in check dams sedimentation and hydrological changes. Subsequently, despite accelerated soil erosion associated with the family contract responsibility system, the check dams, afforestation and a warmer climate mitigated the soil erosion to some extent, runoff and sediment load continued to decrease. Since 1999, China's Grain for Green project has greatly reduced the runoff and sediment load. However, the policy of filling gullies and creating land since 2010 should be reconsidered carefully in terms of all aspects, including the eco-environment, hydrological cycle, and economics. [ABSTRACT FROM AUTHOR]

Secondary inorganic aerosol (especially SNA: sulfate, nitrate, and ammonium) formed from different pathways, account for significant proportions of ambient particulate matter during haze events. For the first time, we quantitatively explored contributions from different SNA formation pathways by an online monitoring AMS instrument and 3‐dimension factor analysis PMF3 model, which is called "SNA formation pathway apportionment". Three formation process were identified: NH4NO3 heterogeneous phase reactions (NH4NO3‐heter), (NH4)2SO4 gas phase reactions ((NH4)2SO4‐gas), and mixed NH4NO3 and (NH4)2SO4 aqueous phase processes (S&N‐aque). Their overall contributions to SNA were 25.7%, 22.1%, and 52.2%, respectively. Moreover, (NH4)2SO4‐gas contributed mainly in clean (52.1%); S&N‐aque got the highest contribution in haze episode (69.6%); while sulfate gas phase formations were also found in haze stage (10.3%). The quantitative findings from this work provide hard evidence that aqueous phase processes (including sulfate aqueous phase reactions and nitrate gas‐particle partition) were major drivers for SNA increasing. Plain Language Summary: Secondary inorganic aerosol (particularly SNA: sulfate, nitrate and ammonium) was found to be the main component of particulate matter in northern China. SNA can be formed through different reaction pathways, such as gas phase, aqueous phase, and heterogeneous reactions pathways. However, quantitative assessments of different pathways are still lacking, especially during different pollution processes. In this work, AMS data with high time resolution and three‐dimension receptor model (PMF3) were used to study the characteristics of secondary aerosols in winter in Beijing and make SNA formation pathway contribution apportionment. Three possible formation pathways were identified by PMF3: Heterogeneous reactions pathway of NH4NO3, gas phase reactions pathway of (NH4)2SO4, and aqueous phase processes of mixed NH4NO3 & (NH4)2SO4, respectively. We found that the main dominant factors were diverse during different periods: (NH4)2SO4 gas phase reactions pathway contributed mainly to SNA in clean period; mixed NH4NO3 and (NH4)2SO4 aqueous phase processes contributed mostly in haze episode. The methods and findings of this work enable and further our understandings on the formations of secondary inorganic aerosol in haze. Key Points: Mixed NH4NO3 and (NH4)2SO4 (aqueous phase process) had the highest contribution during winter haze period (69.6%)(NH4)2SO4 (gas phase formation pathway) contributed mainly in clean (52.1%)(NH4)2SO4 (gas phase formation pathway) was also found during haze pollution stage (10.3%) [ABSTRACT FROM AUTHOR]

Detailed organic carbon isotope (δ13Corg) measurements were conducted on two peat sequences recovered from the north bank of the Yangtze River, East China. Seven radiocarbon dates provided firm age control of this δ13Corg record and reveal palaeoclimatic changes since the Late Glacial period. The results show that the Holocene Megathermal Maximum occurred between 8385 and 7040 cal. yr BP. The Late Glacial climate was generally cold but fluctuated frequently between 12940 and 11815 cal. yr BP. The Older Dryas (from 12940 to 12810 cal. yr BP) and the Younger Dryas (from 12645 to 12170 cal. yr BP) were characterised by cold climate conditions. In contrast, 12810 to 12645 cal. yr BP (corresponding to the Allerød Warm Period) and 12170 to 11815 cal. yr BP (corresponding to a rapid warming period after the Younger Dryas, marking the beginning of the Holocene) were relatively warm phases. In contrast to other high-resolution records, it shows that the δ13Corg records of our study peats are largely controlled by a common forcing mechanism of solar insolation changes in the Northern Hemisphere, and exhibit similar variability to δ18O records obtained from stalagmites and GISP2 during the Late Glacial and early-mid Holocene. [ABSTRACT FROM AUTHOR]

The Northeastern China involves complex interactions between the East Asian summer monsoon (EASM) circulation and the polar climate system, and plays a significant role as the bridge communicating low- and high-latitude climatic processes. High-resolution multi-proxy analysis of a robust accelerator mass spectrometry (AMS) 14C dated lacustrine sediment core recovered from Jingpo Lake in Northeastern China provides a detailed history of EASM variability and vegetation changes since ~5100 cal. yr BP. The period from ~5100 to 3600 cal. yr BP was characterized by the highest pollen percentages of Quercus, Ulmus, Juglans and Corylopsis; low Md (median grain size diameter); and high δ13Corg values, reflecting a relatively warm and humid period. The period between ~3600 and 2100 cal. yr BP is characterized by high Md and low δ13Corg values, and a rapid increase in pollen percentages of herbs, indicating cool and dry climatic conditions. From ~2100 to 150 cal. yr BP, a gradual increase in δ13Corg values and low Md values, and a rapid increase in Carpinus, Juglans and Corylopsis pollen percentages was observed, indicating climate change towards warmer and wetter conditions. After ~150 cal. yr BP, the highest values of total organic carbon mass accumulation rate (TOC-MAR), total nitrogen mass accumulation rate (TN-MAR) and magnetic susceptibility suggesting that the Jingpo Lake region has been severely affected by human activities. The EASM variability in Northeastern China during the mid- to late Holocene shows trends similar to EASM records in China. Furthermore, our findings indicate that the variability of the EASM during the mid- to late Holocene on the multi-decadal to centennial scale was forced by changes in both solar output and oceanic–atmospheric circulation interaction. [ABSTRACT FROM PUBLISHER]