In China, a significant reduction in primary pollution has been observed due to the Clean Air Action since 2013, and ozone pollution has become increasingly prominent over the past years. Pearl River Delta (PRD) is one of the most successful regions concerning primary pollution control, while is suffering from severe ozone pollution during autumn. In this study, we present a field campaign in Shenzhen, a megacity in PRD, in October 2018 with measurements of ozone and photochemical precursors. These observational data are helpful to analyze the local ozone budget and its sensitivity to precursors with the help of an observation-based model (RACM2-LIM1). The observed ozone concentration was up to 121 ppbv during a photochemical episode from 1 to 8 October, when intensive ozone formation up to tens of ppbv/h was found. Ozone vertical measurement indicates the fast ozone production is happening throughout the planetary boundary layer (PBL), which is an important source of morning ozone increase resulting in ozone pollution. An explicit case study is performed to reveal the diurnal feature of instantaneous ozone production rate (P(O-x)) and accumulative P(O-x) based on the O-3-NOx-VOC sensitivity, ROx radical primary production rate (P (ROx)), and L-N/Q for three cases including ozone pollution and attainment periods. Results show that nitrogen oxides (NOx = NO + NO2) reduction have positive and negative impact on local ozone production from one pollution episode to the other, which indicates the complexity of O-3-precursors sensitivity and difficulty to control ozone pollution in Shenzhen. Finally, comparison among measurements in other campaigns provides additional evidence on local ozone production sensitivity on NOx and anthropogenic volatile organic compounds (AVOCs) with respect to a temporal and spatial change. The
Excessive fertilization in rice paddy fields leads to surface water eutrophication, groundwater contamination and air pollution. Determining optimum nitrogen (N) management is essential for maintaining rice yield while reducing the environmental risk caused by N loss. A two-year field experiment (2017–2018) was carried out in a typical paddy field in the middle reaches of the Yangtze River. The WHCNS (soil Water Heat Carbon Nitrogen Simulator) model was calibrated and evaluated for simulations of measured ponding water depth, evapotranspiration, aboveground dry matter, yield, runoff and crop N. The model was then used to evaluate the effects of different N fertilizer rates and split-N application ratios (SNR) practices on crop growth and N losses. Results showed that the model performed well in simulating rice growth and N losses in the region. Ammonia volatilization and denitrification were the mainly pathways of N loss in paddy field, and their two-year average losses were 34% and 38% of the total N loss, respectively. N leaching accounted for 23%, and runoff N loss accounted for 5% of total N loss. N losses were evaluated for two different scenarios and simulated ratios of ammonia volatilization, denitrification, N leaching, and runoff to total N loss under different N management scenarios were 15%–53%, 33%–55%, 6%–30%, and 4%–8%, respectively. Ammonia volatilization and N runoff exponentially increased with an increase of N fertilizer rate, whereas denitrification and N leaching showed an increasing and then a decreasing trend. Yield increased by 36 kg ha−1, and the total N loss decreased by 32.6 kg N ha−1 when the N fertilizer rate was reduced from 231 kg N ha−1 to 155 kg N ha−1 and the SNR was changed from 5:3:1 to 1:1:4. Therefore, reducing the N fertilizer rate and increasing the SNR in the late rice growing season can significantly reduce N loss and effectively improve N use efficiency.
Energy Return on Investment (EROI) has become a policy analysis tool related to sustainability. However, most EROI studies adopt the standard EROI method, which has two inherent defects. First, standard EROI leaves out energy quality. Second, input factors such as labor, auxiliary services and environmental factors are not considered. Therefore, this paper introduces exergy into the EROI calculation and establishes a new extended exergy-based EROI (ExEROI). ExEROI treats “available energy” as energy quality; with the idea of embodied flows, ExEROI quantifies all the five input factors of the EROI analysis framework. Shale gas exploitation in the Sichuan Basin is used as an example in the case study. The ExEROI result is 9.68, which is much lower than the standard EROI result of 82.95. This is due to the inclusion of more input factors and the fact that the input factors are measured by exergy. Specifically, the auxiliary service input factor accounts for 77.10% of the total inputs, and such inputs are ignored by the standard EROI method. ExEROI makes up for the shortcomings of standard EROI and avoids the possible misinformation caused by standard EROI. ExEROI has the potential for use as an integral aspect of energy resource exploitation evaluations.
Particulate nitrate (pNO3–) has often been found to be the major component of fine particles in urban air-sheds in China, the United States, and Europe during winter haze episodes in recent years. However, there is a lack of knowledge regarding the experimentally determined contribution of different chemical pathways to the formation of pNO3–. Here, for the first time, we combine ground and tall-tower observations to quantify the chemical formation of pNO3– using observationally constrained model approach based on direct observations of OH and N2O5 for the urban air-shed. We find that the gas-phase oxidation pathway (OH+NO2) during the daytime is the dominant channel over the nocturnal uptake of N2O5 during pollution episodes, with percentages of 74% in urban areas and 76% in suburban areas. This is quite different from previous studies in some regions of the US, in which the uptake of N2O5 was concluded to account for a larger contribution in winter. These results indicate that the driving factor of nitrate pollution in Beijing and different regions of the US is different, as are the mitigation strategies for particulate nitrate.
A low-pressure reactor (LPR) was developed for the measurement of ambient organic peroxy (RO2) radicals with the use of the laser-induced fluorescence (LIF) instrument. The reactor converts all the ROx (= RO2 + HO2 + RO + OH) radicals into HO2 radicals. It can conduct different measurement modes through altering the reagent gases, achieving the speciated measurement of RO2 and RO2# (RO2 radicals derived from the long-chain alkane, alkene and aromatic hydrocarbon). An example of field measurement results was given, with a maximum concentration of 1.88 x 10(8) molecule/cm(3) for RO2 and 1.18 x 10(8) molecule/cm(3) for RO2#. Also, this instrument quantifies the local ozone production rates directly, which can help to deduce the regional ozone control strategy from an experimental perspective. The new device can serve as a potent tool for both the exploration of frontier chemistry and the diagnosis of the control strategies. (C) 2020 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.
[pls Right Click on picture and Save As...to download the picture]Based on research of basic academic procedures and activities on ancient China Studies, we design a DH cyberinfrastructure conceptual model for ancient China studies(DHC4ACS). The framework is designed to be a digital environment based on open network protocols includes three modules : ·Digitization Module. This module is designed to convert physical objects into digital objects, optical characters recognize, proofread, and finally form an authoritative full-text database with error rate not more than 0.03%. In this module, individuals and different institutes like libraries, museums, archives, galleries could participate in. The authoritative full-text database provide open APIs and rules for any academic use.·Datafication & applications Module. This module is designed to create a large amount of authoritative humanistic datasets, annotate unstructured full texts to transform them into structured ones, and develop various computational applications or digital tools based on datasets and structured full texts. In this module, humanists, IT experts, librarians and field experts work cooperatively or separately, all datasets and structured full texts databases provide open APIs and rules for any academic use.·Digital Ecosystem Module. This module is designed to provide an open digital environment where brings people, information, and computational tools together. The ecosystem runs not only through knowledge lifetime from digitization to datafication, but also through scholars’ academic lifetime from information retrieve, computational tools development to academic achievements production. Humanists could conduct research easily in such digital environment: if they want to retrieve information, they just type the keywords and get it smoothly; if they want to do some further analysis, they can reuse existing datasets and computational tools; while if there is no available data and suitable tools, they could create dataset by themselves according to their requirements or develop new digital tools along with digital technology experts.
To turn the DH Cyberinfrastructure Conceptual Model for Ancient China Studies into reality, we picked ancient Chinese literatures like rare books, rubbings, paintings, calligraphic works, maps as experimental objects. We planned to establish a completed practical procedure for above DHC4ACS.
