With rapid industrialization and urbanization, China is facing a great challenge with regard to severe fog-haze pollutions, which were characterized by high fine particulate concentration level and ...visibility impairment. The control strategies for atmosphere pollutions in China were not only cutting-edge topics of atmospheric research, but also an urgent issue to be addressed by the Chinese government and the public. Focused on the core scientific issues of the haze and fog pollution, this paper reviews the main studies conducted in China, especially after 2010, including formation mechanisms, evolution features, and factors contributing to the fog-haze pollutions. Present policy and control strategies were synoptically discussed. The major challenges ahead will be stated and recommendations for future research directions are proposed at the end of this Review.
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•The effect of the haze and fog events on air quality, climate change and health risk in China are reviewed.•Factors contributing to formation of fog-haze events in China are reviewed.•Advances in the studies of haze and fog pollutions in China are reviewed.•Future directions of haze pollutions in China are suggested.
Ambient ozone (O3) poses great damage to human health, biodiversity, and climate change. Although the health risk due to O3 pollution has been widely evaluated, the spatiotemporal variation of O3 ...level and its potential health impact in a remote tropical island was less concerned. In the present study, we firstly employed an efficient machine learning model named random forest (RF) to fill the missing O3 column amount over Hainan Island of China based on the meteorological factors and other geographical covariates. The result suggested that the RF model achieved the best performance (R2 = 0.87, RMSE = 6.36 DU) among all of the filling methods. We further used an extreme gradient boosting (XGBoost) algorithm to estimate the surface O3 level around Hainan Island on the basis of the full-coverage O3 column amount and other predictors. The XGBoost method showed the better predictive performance (R2 = 0.59, RMSE = 24.14 μg/m3) compared with other estimation models. The predicted O3 concentration exhibited remarkably spatial difference with the highest value observed in Dongfang (77.61 ± 5.25 μg/m3), followed by that in Changjiang (72.51 ± 5.22 μg/m3), and the lowest one in Lingshui (64.16 ± 2.71 μg/m3). Based on the estimated O3 level, we found that the annually mean nonattainment days in Dongfang reached 29.26 ± 35.20 days and about one third of days in the winter fell into the severe O3 pollution over Hainan Island. Besides, the mean all-cause mortalities owing to severe O3 pollution over Hainan Island were calculated to be 391 (95%CI: (212–570)) cases each year, accounting for 0.004% of all the population in Hainan Island. The statistical simulation of O3 level at a remote island updated the traditional knowledge and aroused the public concern on island air pollution.
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•RF showed the best performance in filling the missing O3 column amount.•XGBoost method showed the excellent performance in predicting the O3 level.•The O3 level over Hainan Island displayed the highest value in winter.•The O3-induced total mortalities were estimated to be 391 cases each year.
We present a system for adaptive synthesis of indoor scenes given an empty room and only a few object categories. Automatically suggesting indoor objects and proper layouts to convert an empty room ...to a 3D scene is challenging, since it requires interior design knowledge to balance the factors like space, path distance, illumination and object relations, in order to insure the functional plausibility of the synthesized scenes. We exploit a database of 2D floor plans to extract object relations and provide layout examples for scene synthesis. With the labeled human positions and directions in each plan, we detect the activity relations and compute the coexistence frequency of object pairs to construct activity-associated object relation graphs. Given the input room and user-specified object categories, our system first leverages the object relation graphs and the database floor plans to suggest more potential object categories beyond the specified ones to make resulting scenes functionally complete, and then uses the similar plan references to create the layout of synthesized scenes. We show various synthesis results to demonstrate the practicability of our system, and validate its usability via a user study. We also compare our system with the state-of-the-art furniture layout and activity-centric scene representation methods, in terms of functional plausibility and user friendliness.
Marine macroalgae Enteromorpha prolifera, one of the main algae genera for green tide, was converted to bio-oil by hydrothermal liquefaction in a batch reactor at temperatures of 220−320 °C. The ...liquefaction products were separated into a dichloromethane-soluble fraction (bio-oil), water-soluble fraction, solid residue, and gaseous fraction. Effects of the temperature, reaction time, and Na2CO3 catalyst on the yields of liquefaction products were investigated. A moderate temperature of 300 °C with 5 wt % Na2CO3 and reaction time of 30 min led to the highest bio-oil yield of 23.0 wt %. The raw algae and liquefaction products were analyzed using elemental analysis, Fourier transform infrared (FTIR) spectroscopy, gas chromatography−mass spectrometry (GC−MS), and 1H nuclear magnetic resonance (NMR). The higher heating values (HHVs) of bio-oils obtained at 300 °C were around 28−30 MJ/kg. The bio-oil was a complex mixture of ketones, aldehydes, phenols, alkenes, fatty acids, esters, aromatics, and nitrogen-containing heterocyclic compounds. Acetic acid was the main component of the water-soluble products. The results might be helpful to find a possible strategy for use of byproducts of green tide as feedstock for bio-oil production, which should be beneficial for environmental protection and renewable energy development.
China has been suffered from the severe sulfur dioxide (SO2) pollution in the past decades. The spatiotemporal estimation and health effect assessment of SO2 using two-stage machine learning models ...have not been performed yet. In this study, a high-quality model named random forest coupled with spatiotemporal Kriging (RF-STK) model was developed to estimate the daily SO2 concentration across the entire China from May 2014 to May 2015 based on the satellite data and geographic covariates. Compared with other statistical methods, the RF-STK model showed the better explanatory performance, with the 10-fold cross-validation R2 = 0.62 (root-mean-square error (RMSE) = 10.36 μg/m3) for daily estimations. The annually mean population-weighted SO2 concentration was estimated to be 30.49 ± 10.83 μg/m3 (mean ± standard deviation). The SO2 levels displayed the remarkably seasonal variation with the peak in winter (47.27 ± 22.64 μg/m3), followed by ones in autumn (28.41 ± 10.41 μg/m3) and spring (25.92 ± 7.95 μg/m3), and in summer (21.33 ± 6.51 μg/m3). At the national scale, only 20.31% of the population lived in the safe regions (population-weighted SO2 concentration < 20 μg/m3). The higher population-weighted SO2 concentrations were mainly concentrated on some provinces of North China Plain (NCP) (e.g., Shanxi, Hebei, Shandong), followed by the provinces of Northeast China, and the lowest one in Hainan (8.31 ± 1.38 μg/m3). The mean all-cause mortalities due to excessive SO2 exposure were estimated to be 131,957 cases, accounting for 0.009% of the whole Chinese population. Among all of the diseases, the mortalities per year were in the order of respiratory disease (RD) (11913 cases) > cardiovascular disease (CVD) (11386 cases) > chronic obstructive pulmonary disease (COPD) (8112 cases) > cerebrovascular disease (CEVD) (2188 cases). The statistical modelling of SO2 at a national scale provided the valuable data for epidemiological research and air pollution prevention.
•The annually mean SO2 concentration was estimated to be 25.87 ± 10.83 μg/m3.•The highest population-weighted SO2 concentration occurs in NCP.•79.69% of the population suffered from the excessive SO2 exposure over China.•The all-cause mortalities induced by SO2 exposure in China reached 131,957 cases each year.
Biomass burning (BB) is a significant air pollution source, with global, regional and local impacts on air quality, public health and climate. Worldwide an extensive range of studies has been ...conducted on almost all the aspects of BB, including its specific types, on quantification of emissions and on assessing its various impacts. China is one of the countries where the significance of BB has been recognized, and a lot of research efforts devoted to investigate it, however, so far no systematic reviews were conducted to synthesize the information which has been emerging. Therefore the aim of this work was to comprehensively review most of the studies published on this topic in China, including literature concerning field measurements, laboratory studies and the impacts of BB indoors and outdoors in China. In addition, this review provides insights into the role of wildfire and anthropogenic BB on air quality and health globally. Further, we attempted to provide a basis for formulation of policies and regulations by policy makers in China.
Open field biomass burning causes severe air pollution, public health risk and potential climate impact. a) Photo taken in Changzhou rural area on June 10, 2015; b) Photo taken in Hebei rural area on October 23, 2013; c) A traditional indoor burner in rural area in China; d) Tar ball emitted from biomass burning. Display omitted
•This review discusses wildfire and anthropogenic emission from biomass burning in China.•Field observations and laboratory studies on public health and climate impacts of biomass burning•Atmospheric process of biomass burning plumes and their transport•Proposed research priorities and insights about biomass burning in China
Volatile organic compounds (VOCs) are a kind of important precursors for ozone photochemical formation. In this study, VOCs were measured from November 5th, 2013 to January 6th, 2014 at the Second ...Jinshan Industrial Area, Shanghai, China. The results showed that the measured VOCs were dominated by alkanes (41.8%), followed by aromatics (20.1%), alkenes (17.9%), and halo-hydrocarbons (12.5%). The daily trend of the VOC concentration showed a bimodal feature due to the rush-hour traffic in the morning and at nightfall. Based on the VOC concentration, a receptor model of Positive Matrix Factorization (PMF) coupled with the information related to VOC sources was applied to identify the major VOC emissions. The result showed five major VOC sources: solvent use and industrial processes were responsible for about 30% of the ambient VOCs, followed by rubber chemical industrial emissions (23%), refinery and petrochemical industrial emissions (21%), fuel evaporations (13%) and vehicular emissions (13%). The contribution of generalized industrial emissions was about 74% and significantly higher than that made by vehicle exhaust. Using a propylene-equivalent method, alkenes displayed the highest concentration, followed by aromatics and alkanes. Based on a maximum incremental reactivity (MIR) method, the average hourly ozone formation potential (OFP) of VOCs is 220.49 ppbv. The most significant source for ozone chemical formation was identified to be rubber chemical industrial emissions, following one by vehicular emission. The data shown herein may provide useful information to develop effective VOC pollution control strategies in industrialized area.
Source profiles (percentage of species total) resolved from Positive Matrix Factorization (PMF). Display omitted
Color theme or color palette can deeply influence the quality and the feeling of a photograph or a graphical design. Although color palettes may come from different sources such as online ...crowd-sourcing, photographs and graphical designs, in this paper, we consider color palettes extracted from fine art collections, which we believe to be an abundant source of stylistic and unique color themes. We aim to capture color styles embedded in these collections by means of statistical models and to build practical applications upon these models. As artists often use their personal color themes in their paintings, making these palettes appear frequently in the dataset, we employed density estimation to capture the characteristics of palette data. Via density estimation, we carried out various predictions and interpolations on palettes, which led to promising applications such as photo-style exploration, real-time color suggestion, and enriched photo recolorization. It was, however, challenging to apply density estimation to palette data as palettes often come as unordered sets of colors, which make it difficult to use conventional metrics on them. To this end, we developed a divide-and-conquer sorting algorithm to rearrange the colors in the palettes in a coherent order, which allows meaningful interpolation between color palettes. To confirm the performance of our model, we also conducted quantitative experiments on datasets of digitized paintings collected from the Internet and received favorable results.
Fluorinated Bi2WO6 catalyst was synthesized by a simple hydrothermal process. The effects of fluorine doping on crystal structure, optical property, photoinduced hydrophilicity, surface acidity, and ...photocatalytic activity of the as-prepared sample were observed in detail. Fluorinated Bi2WO6 presented the enhanced photoactivity for the RhB degradation under the simulative sunlight (λ > 290 nm), which could be a synergetic effect of the surface fluorination and the doping of crystal lattice. To get a better handle on the mechanistic details of this photocatalytic system, the photodegradation process of RhB was examined. In the fluorinated Bi2WO6 system, five intermediates, namely, N,N-diethyl-N′-ethylrhodamine, N,N-diethylrohodamine, N-ethyl-N′-ethylrhodamine, N-ethylrhodamine, and rhodamine were thus identified, whereas the first three intermediates could only be identified in the case of the Bi2WO6 system. This result indicated that more RhB molecules were degraded via the deethylation process in the fluorinated Bi2WO6 system. It was proposed that the F−-containing function on the catalyst surface could serve as an electron-trapping site and enhance interfacial electron-transfer rates by tightly holding trapped electrons. On the basis of the experimental results, a photocatalytic mechanism was discussed in detail.
Dynamic changes in flavonoid, total phenol, and antioxidant potential in different Prunus humilis accessions during fruit development stages were studied in order to provide a reference for the ...optimum harvest time for flavonoid extraction. 'Nongda 4', 'Nongda 5', 'DS-1' and '02-16' were selected as plant materials to determine the content of flavonoid, total phenol and antioxidant indices during six fruit development stages. Changes in total flavonoid content (TFC) and total phenol content (TPC) in different accessions of P. humilis were slightly different depending on the development stage of P. humilis fruit. TFC and TPC in 'Nongda 5' fruit showed a trend of continuous decline. There was a small increase in TFC and TPC from the young fruit stage to the stone hardening stage, followed by a decreasing trend, and then to the lowest level at the ripening stage of 'Nongda 4', 'DS-1', and '02-16' fruits. The trend of antioxidant capacity (ABTS, FRAP, DPPH) with the TFC and TPC of P. humilis fruit was basically the same, and the correlation analysis results showed that the TFC of P. humilis fruit was positively correlated with the antioxidant indices (P<0.01). Catechin (CC), rutin (RT), and quercetin-7-O-β-D-glucopyranoside (Q7G) were detected in all the fruit development stages of the four P. humilis fruits. Among them, catechin was the most abundant component, accounting for approximately 10%. Myricetin (MC) and quercetin (QC) were generally detected only in the early fruit development stage, but not in the later fruit development stage. Correlation analysis showed that the flavonoid components with TFC, TPC, and antioxidant indices differed between the different accessions. RT, CC, and liquiritigenin (LR) had a stronger correlation with TFC and antioxidant indices. Cyanidin-3-O-glucoside (C3G) was not detected until the coloring stage in two red P. humilis accessions ('Nongda 4' and 'DS-1'), and so it is better to choose a red P. humilis fruit to extract C3G at the ripening stage. Selecting an early stage of fruit development, especially the stone hardening stage, was important for extracting flavonoids, total phenols and other components. We believe that our results will provide basic information and reference for evaluation of fruit nutrition and health benefits, breeding of functional new varieties, and efficient utilization of P. humilis fruit.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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