The chemical characteristics（water-soluble ions and carbonaceous species） of PM2.5 in Guangzhou were measured during a typical haze episode.Most of the chemical species in PM2.5 showed significant difference between...The chemical characteristics（water-soluble ions and carbonaceous species） of PM2.5 in Guangzhou were measured during a typical haze episode.Most of the chemical species in PM2.5 showed significant difference between normal and haze days.The highest contributors to PM2.5 were organic carbon（OC）,nitrate,and sulfate in haze days and were OC,sulfate,and elemental carbon（EC） in normal days.The concentrations of secondary species such as,NO3^-,SO4^2-,and NH4^＋ in haze days were 6.5,3.9,and 5.3 times higher than those in normal days,respectively,while primary species（EC,Ca^2＋,K^＋） show similar increase from normal to haze days by a factor about 2.2-2.4.OC/EC ratio ranged from 2.8 to 6.2 with an average of 4.7 and the estimation on a minimum OC/EC ratio showed that SOC（secondary organic carbon） accounted more than 36.6% for the total organic carbon in haze days.The significantly increase in the secondary species（SOC,NO3^-,SO4^2-,and NH4^＋）,especially in NO3^-,caused the worst air quality in this region.Simultaneously,the result illustrated that the serious air pollution in haze episodes was strongly correlated with the meteorological conditions.During the sampling periods,air pollution and visibility had a good relationship with the air mass transport distance;the shorter air masses transport distance,the worse air quality and visibility in Guangzhou,indicating the strong domination of local sources contributing to haze formation.High concentration of the secondary aerosol in haze episodes was likely due to the higher oxidation rates of sulfur and nitrogen species.展开更多
PM2.5 samples for 24h were collected during winter in Tianjin, China. The ambient mass concentration and chemical composition of the PM2.5 were determined. Ionic species were analyzed by ion chromatography, while carb...PM2.5 samples for 24h were collected during winter in Tianjin, China. The ambient mass concentration and chemical composition of the PM2.5 were determined. Ionic species were analyzed by ion chromatography, while carbonaceous species were determined with the IMPROVE thermal optical reflectance （TOR） method, and inorganic elements were measured by inductively coupled plasma-atomic emission spectrometer. The daily PM2.5 mass concentrations ranged from 48.2 to 319.2 μg/m^3 with an arithmetic average of 144.6 μg/m^3. The elevated PM2.5 in winter was mostly attributed to combustion sources such as vehicle exhaust, heating, cooking and industrial emissions, low wind speeds and high relative humidity （RH）, which were favorable for pollutant accumulation and formation of secondary pollutants. By chemical mass balance, it was estimated that about 89.1% of the PM2.5 mass concentrations were explained by carbonaceous species, secondary particles, crustal matters, sea salt and trace elements. Organic material was the largest contributor, accounting for about 32.7% of the total PM2.5 mass concentrations. SO4^2-, NO3^-, Cl^- and NH4^＋ were four major ions, accounting for 16.6%, 11.5%, 4.7% and 6,0%, respectively, of the total mass of PM2.5.展开更多
Twenty-three progressive extractions were performed to study individual humic acids (HAs) and humin fractions from a typical black soil (Mollisol) in Heilongjiang Province, China using elemental analysis and spectrosc...Twenty-three progressive extractions were performed to study individual humic acids (HAs) and humin fractions from a typical black soil (Mollisol) in Heilongjiang Province, China using elemental analysis and spectroscopic techniques. After 23 HA extractions the residue was separated into high and low organic carbon humin fractions. HA yield was the highest for the first extraction and then gradually decreased with further extractions. Organic carbon (OC) of the humin fractions accounted for 58% of total OC …展开更多
PM2.5 samples were collected at urban, industrial and coastal sites in Tianjin during winter, spring and summer in 2007. Concentrations of elemental carbon （EC） and organic carbon （OC） were analyzed using the IMPR...PM2.5 samples were collected at urban, industrial and coastal sites in Tianjin during winter, spring and summer in 2007. Concentrations of elemental carbon （EC） and organic carbon （OC） were analyzed using the IMPROVE thermal-optical reflectance （TOR） method. Both OC and EC exhibited a clear seasonal pattern with higher concentrations observed in the winter than in the spring and summer, due to cooperative effect of changes in emission rates and seasonal meteorology. The concentrations of carbonaceous species were also influenced by the local factors at different sampling sites, ranking in the order of industrial〉 urban 〉 coastal during winter and spring. In the summer, the port emissions, enriched with EC, had a significant impact on carbonaceous aerosols at the coastal site. Total carbonaceous aerosol accounted for 40.0% in winter, 33.8% in spring and 31.4% in summer of PM2.5 mass. Good correlation （R = 0.84-0.93） between OC and EC indicated that they had common dominant sources of combustion such as coal burning and traffic emissions. The daily average OC/EC ratios ranged from 2.1 to 9.1, the elevated OC/EC ratios being found in the winter. The estimated secondary organic carbon （SOC） accounted for 46.9%, 35.3% and 40.2% of the total OC in the winter, spring and summer, respectively, indicating that SOC may be an important contributor to fine organic aerosol in Tianjin.展开更多
The humic acids (HAs) isolated from the sediments of the various rivers,lakes,and reservoirs in China were studied using elemental analyzer,fourier transform infrared (FT-IR),and CP/MAS 13C nuclear magnetic resonance ...The humic acids (HAs) isolated from the sediments of the various rivers,lakes,and reservoirs in China were studied using elemental analyzer,fourier transform infrared (FT-IR),and CP/MAS 13C nuclear magnetic resonance (NMR) spectroscopy.The results showed that the HAs were characterized by some common chemical and physicochemical properties,but they also pose some differences in the C-containing functional groups.The C/N,C/H,O/C,and O/H ratios differ widely for the various HAs,showing that the elemental comp...展开更多
Xiamen, located on the southeastern coastal line of China, is undergoing rapid urbanization and industrialization, so its air quality has a trend of degradation. However, studies on level, temporal and spatial changes...Xiamen, located on the southeastern coastal line of China, is undergoing rapid urbanization and industrialization, so its air quality has a trend of degradation. However, studies on level, temporal and spatial changes of fine particles （PM2.5） and their carbonaceous fractions are scarce. In this article, abundance, sources, seasonal and spatial variations, distribution of organic carbon （OC） and elemental carbon （EC） in PM2.5, were studied at suburban, urban and industrial sites in Xiamen during four season-representative months in 2009-2010. PM2.5 samples were collected with middle volume sampler and were analyzed for OC and EC with thermal optical transmittance （TOT） method. Results showed that the annual average PM2.5 concentrations were 63.88-74.80 Ixg/m3 at three sites. While OC and EC concentrations were in the range of 15.81-19.73 [xg/m3 and 2.74-3.49 ~tg/m3, respectively, and clearly presented the summer minima and winter maxima in this study. The carbonaceous aerosol accounted for 42.8%-47.3% of the mass of PMzs. The annual average of secondary organic carbon （SOC） concentrations in Xiamen were 9.23-11.36 ~g/m3, accounting for approximately 56% of OC. Strong correlations between OC and EC was found in spring （R2 = 0.50） and autumn （R2 = 0.73）, suggesting that there were similar emission and transport processes for carbonaceous aerosols in these two seasons, while weak correlations were found in summer （R2 = 0.33） and winter （R2 = 0.41）. The OCI＇EC ratios in PM2.5 varied from 2.1 to 8.7 with an annual average of 5.7, indicating that vehicle exhaust, coal smoke and biomass burning were main source apportionments of carbonaceous fractions in Xiamen.展开更多
Background One of the major causes of death in severe acute pancreatitis （SAP） is severe infection owing to bacterial translocation. Some clinical studies suggested that ecoimmunonutrition （EIN） as a new strategy ...Background One of the major causes of death in severe acute pancreatitis （SAP） is severe infection owing to bacterial translocation. Some clinical studies suggested that ecoimmunonutrition （EIN） as a new strategy had better treatment effect on SAP patients. But the experiment studies on the precise mechanism of the effect of EIN were less reported. In this study, we mainly investigated the effects of EIN on bacterial translocation in SAP model of dogs. Methods SAP was induced by retrograde infusion of 5% sodium taurocholate into the pancreatic duct in healthy hybrid dogs. The SAP dogs were supported with either parenteral nutrition （PN） or elemental enteral nutrition （EEN） or EIN. The levels of serum amylase, serum aminotransferase and plasma endotoxin were detected before and after pancreatitis induction. On the 7th day after nutrition supports, peritoneal fluid, mesenteric lymph nodes （MLN）, liver, and pancreas were collected for bacterial culture with standard techniques to observe the incidence of bacterial translocation. Pathology changes of pancreas were analyzed by histopathologic grading and scoring of the severity of pancreas, and the degree of intestinal mucosal damage was assessed by measuring mucosal thickness, villus height, and crypt depth of ileum. Results Compared with PN and EEN, EIN significantly decreased the levels of serum amylase, serum aminotransferase, plasma endotoxin, and the incidence of bacterial translocation. Furthermore, compared with the others, the histology scores of inflammation in pancreas and the ileum injury （ileum mocosa thickness, villus height, and crypt depth） were significantly alleviated by EIN （P〈0.05）. Moreover, concerning liver function, the serum levels of alanine aminotransferase, aspartate aminotransferase and albumin were ameliorating significantly in the EIN group. Conclusion Our results suggested that EIN could maintain the integrity of intestinal mucosal barrier and reducing the incidence of bacterial translocation in SAP dogs. Ea展开更多
An intensive observation of organic carbon （OC） and element carbon （EC） in PM10 and gaseous materials （SO2, CO, and O3,） was conducted continuously to assess the characteristics of wintertime carbonaceous aeroso...An intensive observation of organic carbon （OC） and element carbon （EC） in PM10 and gaseous materials （SO2, CO, and O3,） was conducted continuously to assess the characteristics of wintertime carbonaceous aerosols in an urban area of Beijing, China. Results showed that the averaged total carbon （TC） and PM10 concentrations in observation period are 30.2±120.4 and 172.6±198.3 μ/m^3 respectively. Average OC concentration in nighttime （24.9±19.6 μ/m^3 was 40% higher than that in daytime （17.7±10.9 μ/m^3. Average EC concentrations in daytime （8.8±15.2 μ/m^3 was close to that in nighttime （8.9±15.1 μ/m^3. The OC/EC ratios in nighttime ranging from 2.4 to 2.7 are higher than that in daytime ranging from 1.9 to 2.0. The concentrations of OC, EC, PM10 were low with strong winds and high with weak winds. The OC and EC were well correlated with PM10, CO and SO2, which implies they have similar sources. OC and EC were not well correlated with O3. By considering variation of OC/EC ratios in daytime and night time, correlations between OC and O3, and meteorological condition, we speculated that OC and EC in Beijing PM10 were emitted as the primary particulate form. Emission of motor vehicle with low OC/EC ratio and coal combustion sources with high OC/EC ratio are probably the dominant sources for carbonaceous aerosols in Beijing in winter. A simple method was used to estimate the relative contribution of sources to carbonaceous aerosols in Beijing PM10. Motor vehicle source accounts for 80% and 68%, while coal combustion accounts for 20% and 32% in daytime and nighttime, respectively in Beijing. Averagely, the motor vehicle and coal combustion accounted for 74% and 26%, respectively, for carbonaceous aerosols during the observation period. It points to the motor vehicle is dominant emission for carbonaceous aerosols in Beijing PM10 in winter period, which should be paid attention to control high level of PM10 in Beijing effectively.展开更多
Concentrations and spatial distributions of organic carbon (OC) and elemental carbon (EC) in atmospheric particles were measured at 8 sites in four cities (Hong Kong, Guangzhou, Shenzhen and Zhuhai) of Pearl River Del...Concentrations and spatial distributions of organic carbon (OC) and elemental carbon (EC) in atmospheric particles were measured at 8 sites in four cities (Hong Kong, Guangzhou, Shenzhen and Zhuhai) of Pearl River Delta Region (PRDR), China during 2001 winter period and 2002 summer period. PM2.5 (particie diameter smaller than 2.5 um) and PM10 (particie diameter smaller than 10 um) samples were collected on pre-fired quartz filters with mini-volume samplers and analyzed using thermal optical reflectance (TOR) method. The average PM2.5and PM10 Ievel were 60.1 and 93.1 μg·m-3, respectively, with PM2.5 constituting 65.3% of the PM10 mass. The average OC and EC concentrations in PM2.5 were 12.0 and 5.1 μg·m-3, respectively, while those in PM10 were 16.0 and 6.5 μg·m-3, respectively. The carbo-naceous aerosol accounted for 37.2% of the PM2.5 and 32.8% of the PM10. The highest concentrations of OC and EC were observed at Guangzhou city in both vvinter and summer seasons. The average OC/EC ratios were 2.4 for PM2.5 and 2.5 for PM10, indicating the presence of secondary organic aerosols. The OC and EC in PRDR were found to be strongly correlated (correlation coefficients > 0.6), which implied that similar emission source contribute to the ambient carbon particles.展开更多
An investigation of gaseous elemental mercury concentration in atmosphere was conducted at Beijing and Guangzhou urban, Yangtze Delta regional sites and China Global Atmosphere Watch Baseline Observatory （CGAWBO） in...An investigation of gaseous elemental mercury concentration in atmosphere was conducted at Beijing and Guangzhou urban, Yangtze Delta regional sites and China Global Atmosphere Watch Baseline Observatory （CGAWBO） in Mt. Waliguan of remote continental area of China. High temporal resolved data were obtained using automated mercury analyzer RA-915^＋. Results showed that the overall hourly mean Hg^0 concentrations in Mt. Waliguan were 1.7±1.1 ng/m3 in summer and 0.6±0.08 ng/m^3 in winter. The concentration in Yangtze Delta regional site was 5.4±4.1 ng/m^3, which was much higher than those in Waliguan continental background area and also higher than that found in North America and Europe rural areas. In Beijing urban area the overall hourly mean Hg^0 concentrations were 8.3±3.6 ng/m^3 in winter, 6.5±5.2 ng/m^3 in spring, 4.9±3.3 ng/m^3 in summer, and 6.7±3.5 ng/m^3 in autumn, respectively, and the concentration was 13.5±7.1 ng/m^3 in Guangzhou site. The mean concentration reached the lowest value at 14：00 and the highest at 02：00 or 20：00 in all monitoring campaigns in Beijing and Guangzhou urban areas, which contrasted with the results measured in Yangtze Delta regional site and Mr. Waliguan. The features of concentration and diurnal variation of Hg^0 in Beijing and Guangzhou implied the importance of local anthropogenic sources in contributing to the high Hg^0 concentration in urban areas of China. Contrary seasonal variation patterns of Hg^0 concentration were found between urban and remote sites. In Beijing the highest Hg^0 concentration was in winter and the lowest in summer, while in Mt. Waliguan the Hg^0 concentration in summer was higher than that in winter. These indicated that different processes and factors controlled Hg^0 concentration in urban, regional and remote areas.展开更多
Various studies have established that feedstock choice,pyrolysis temperature,and pyrolysis type influence final biochar physicochemical characteristics.However,overarching analyses of pre-biochar creation choices and ...Various studies have established that feedstock choice,pyrolysis temperature,and pyrolysis type influence final biochar physicochemical characteristics.However,overarching analyses of pre-biochar creation choices and correlations to biochar characteristics are severely lacking.Thus,the objective of this work was to help researchers,biochar-stakeholders,and practitioners make more well-informed choices in terms of how these three major parameters influence the final biochar product.Utilizing approximately 5400 peer-reviewed journal articles and over 50,800 individual data points,herein we elucidate the selections that influence final biochar physical and chemical properties,total nutrient content,and perhaps more importantly tools one can use to predict biochar’s nutrient availability.Based on the large dataset collected,it appears that pyrolysis type(fast or slow)plays a minor role in biochar physico-(inorganic)chemical characteristics;few differences were evident between production styles.Pyrolysis temperature,however,affects biochar’s longevity,with pyrolysis temperatures>500℃ generally leading to longer-term(i.e.,>1000 years)half-lives.Greater pyrolysis temperatures also led to biochars containing greater overall C and specific surface area(SSA),which could promote soil physico-chemical improvements.However,based on the collected data,it appears that feedstock selection has the largest influence on biochar properties.Specific surface area is greatest in wood-based biochars,which in combination with pyrolysis temperature could likely promote greater changes in soil physical characteristics over other feedstock-based biochars.Crop-and other grass-based biochars appear to have cation exchange capacities greater than other biochars,which in combination with pyrolysis temperature could potentially lead to longer-term changes in soil nutrient retention.The collected data also suggest that one can reasonably predict the availability of various biochar nutrients(e.g.,N,P,K,Ca,Mg,Fe,and Cu)based on feedstock choi展开更多
Microorganisms are major drivers of elemental cycling in the biosphere. Determining the abundance of microbial functional traits involved in the transformation of nutrients, including carbon(C), nitrogen(N), phosphoru...Microorganisms are major drivers of elemental cycling in the biosphere. Determining the abundance of microbial functional traits involved in the transformation of nutrients, including carbon(C), nitrogen(N), phosphorus(P) and sulfur(S), is critical for assessing microbial functionality in elemental cycling. We developed a high-throughput quantitative-PCR-based chip, Quantitative microbial element cycling(QMEC), for assessing and quantifying the genetic potential of microbiota to mineralize soil organic matter and to release C, N, P and S. QMEC contains 72 primer pairs targeting 64 microbial functional genes for C, N, P, S and methane metabolism. These primer pairs were characterized by high coverage(average of 18–20 phyla covered per gene)and sufficient specificity(>70% match rate) with a relatively low detection limit(7–102 copies per run). QMEC was successfully applied to soil and sediment samples, identifying significantly different structures, abundances and diversities of the functional genes(P<0.05). QMEC was also able to determine absolute gene abundance. QMEC enabled the simultaneous qualitative and quantitative determination of 72 genes from 72 samples in one run, which is promising for comprehensively investigating microbially mediated ecological processes and biogeochemical cycles in various environmental contexts including those of the current global change.展开更多
Heterogeneous oxidation of gas-phase Hg 0 by nano-Fe 2 O 3 was investigated on a fixed bed reactor, and the effects of oxygen concentration, bed temperature, water vapour concentration and particle size have been disc...Heterogeneous oxidation of gas-phase Hg 0 by nano-Fe 2 O 3 was investigated on a fixed bed reactor, and the effects of oxygen concentration, bed temperature, water vapour concentration and particle size have been discussed. The results showed that Hg 0 could be oxidized by active oxygen atom on the surface of nano-Fe 2 O 3 as well as lattice oxygen in nano-Fe 2 O 3 . Among the factors that affect Hg 0 oxidation by nano-Fe 2 O 3 , bed temperature plays an important role. More than 40% of total mercury was oxidized at 300°C, however, the test temperature at 400°C could cause sintering of nano-catalyst, which led to a lower efficiency of Hg 0 oxidation. The increase of oxygen concentration could promote mercury oxidation and led to higher Hg 0 oxidation efficiency. No obvious mercury oxidation was detected in the pure N 2 atmosphere, which indicates that oxygen is required in the gas stream for mercury oxidation. The presence of water vapour showed different effects on mercury oxidation depending on its concentration. The lower content of water vapour could promote mercury oxidation, while the higher content of water vapour inhibits mercury oxidation.展开更多
Atmospheric fine particles （PM2.5） were collected in this study with middle volume samplers in Fuzhou, China, during both normal days and haze days in summer （September 2007） and winter （january 2008）. The conce...Atmospheric fine particles （PM2.5） were collected in this study with middle volume samplers in Fuzhou, China, during both normal days and haze days in summer （September 2007） and winter （january 2008）. The concentrations, distributions, and sources of polycyclic aromatic hydrocarbons （PAHs）, organic carbon （OC）, elemental carbon （EC）, and water soluble inorganic ions （WSIls） were determinated. The results showed that the concentrations of PM2.s, PAHs, OC, EC, and WSIIs were in the orders of haze 〉 normal and winter〉 summer. The dominant PAHs of PM2.s in Fuzhou were Fluo, Pyr, Chr, BbF, BkF, BaP, BghiP, and IcdP, which represented about 80.0% of the total PAHs during different sampling periods. The BaPeq concentrations of ^-~PAHs were 0.78, 0.99, 1.22, and 2.43 ng/m3 in summer normal, summer haze, winter normal, and winter haze, respectively. Secondary pollutants （SO42 , NO3 , NH4＊, and OC） were the major chemical compositions of PM2.5, accounting for 69.0%, 55.1%, 63.4%, and 64.9% of PM2.s mass in summer normal, summer haze, winter normal, and winter haze, respectively. Correspondingly, secondary organic carbon （SOC） in Fuzhou accounted for 20.1%, 48.6%, 24.5%, and 50.5% of OC. The average values of nitrogen oxidation ratio （NOR） and sulfur oxidation ratio （SOR） were higher in haze days （0.08 and 0.27） than in normal days （0.05 and 0.22）. Higher OC/EC ratios were also found in haze days （5.0） than in normal days （3.3）. Correlation analysis demonstrated that visibility had positive correlations with wind speed, and neg- ative correlations with relative humidity and major air pollutants. Overall, the enrichments of PM2.5, OC, EC, SO42 ,andNO3 promoted haze formation. Furthermore, the diagnostic ratios of IcdP/（IcdP ＋ BghiP）, lcdP/BghiP, OC/EC, and NO3 /SO42 indicated that vehicle exhaust and coal consumption were the main sources of pollutants in Fuzhou.展开更多
PM10 （particulate matter with aerodynamic diameter less than 10 μm） samples were collected simultaneously at nine urban sites and one urban background site during two intensive observation campaigns in 2006. Concen...PM10 （particulate matter with aerodynamic diameter less than 10 μm） samples were collected simultaneously at nine urban sites and one urban background site during two intensive observation campaigns in 2006. Concentrations of elemental carbon （EC） and organic carbon （OC） in PM10 were analyzed using an element analyzer. The characteristics regarding spatial and seasonal distribution patterns of OC and EC concentrations and their contributions to PM10 mass, as well as correlation between OC and EC, were investigated in detail. The average OC and EC concentrations for urban sites were 57.5 ± 20.8 and 8.3 ± 3.9 μg/m^3, respectively, both being around three times higher than those for urban background site. As a whole, EC concentrations did not show distinct seasonal variations, though OC concentrations were generally higher in autumn than in spring. For urban sites, total carbonaceous aerosol （TCA） accounted for 33.2% in spring and 35.0% in autumn of PM10 mass. The OC and EC concentrations were found significantly correlated to each other both in spring and in autumn, implying the existence of similar emission sources such as coal combustion. The OC/EC ratios generally exceeded 2.0, indicating the presence of secondary organic carbon （SOC）, whose estimated concentration for urban Chongqing was 26.7 and 39.4μg/m^3, accounting for 48.9 and 61.9% of the total OC observed in the samples, in spring and in autumn, respectively.展开更多
In 1999 aerosol samples were collected by cascade at Meteorological Tower in Beijing. The 12 group aerosol samples obtained were analyzed using PIXE method, which resulted in 20 elemental concentrations and size dist...In 1999 aerosol samples were collected by cascade at Meteorological Tower in Beijing. The 12 group aerosol samples obtained were analyzed using PIXE method, which resulted in 20 elemental concentrations and size distribution of elemental concentrations. From the observation, the elemental concentrations, size distribution of elemental concentrations and their variations are analyzed. It shows that concentrations of the most elements in aerosols increase greatly compared with those in the past except that the concentrations of V, K, Sr, and the source of aerosols has changed greatly in the past decade. Fine mode aerosols increase more rapidly in the past decade, which may be due to the contribution of coal combustion and automobile exhaust. Pb content in aerosol is much higher than that at the beginning of 1980s, and has a decreasing trend in recent years because of using non leaded gasoline.展开更多
基金supported by the National Excellent Youth Foundation of China (No. 20625722)the China Postdoctoral Science Foundation (No. 20080430396)
文摘The chemical characteristics（water-soluble ions and carbonaceous species） of PM2.5 in Guangzhou were measured during a typical haze episode.Most of the chemical species in PM2.5 showed significant difference between normal and haze days.The highest contributors to PM2.5 were organic carbon（OC）,nitrate,and sulfate in haze days and were OC,sulfate,and elemental carbon（EC） in normal days.The concentrations of secondary species such as,NO3^-,SO4^2-,and NH4^＋ in haze days were 6.5,3.9,and 5.3 times higher than those in normal days,respectively,while primary species（EC,Ca^2＋,K^＋） show similar increase from normal to haze days by a factor about 2.2-2.4.OC/EC ratio ranged from 2.8 to 6.2 with an average of 4.7 and the estimation on a minimum OC/EC ratio showed that SOC（secondary organic carbon） accounted more than 36.6% for the total organic carbon in haze days.The significantly increase in the secondary species（SOC,NO3^-,SO4^2-,and NH4^＋）,especially in NO3^-,caused the worst air quality in this region.Simultaneously,the result illustrated that the serious air pollution in haze episodes was strongly correlated with the meteorological conditions.During the sampling periods,air pollution and visibility had a good relationship with the air mass transport distance;the shorter air masses transport distance,the worse air quality and visibility in Guangzhou,indicating the strong domination of local sources contributing to haze formation.High concentration of the secondary aerosol in haze episodes was likely due to the higher oxidation rates of sulfur and nitrogen species.
基金supported by National Natural Science Foundation of China (Grant No. 20677030)Tianjin Science and Technology Development Commission (Grant No. 06YFSYSF02900)
文摘PM2.5 samples for 24h were collected during winter in Tianjin, China. The ambient mass concentration and chemical composition of the PM2.5 were determined. Ionic species were analyzed by ion chromatography, while carbonaceous species were determined with the IMPROVE thermal optical reflectance （TOR） method, and inorganic elements were measured by inductively coupled plasma-atomic emission spectrometer. The daily PM2.5 mass concentrations ranged from 48.2 to 319.2 μg/m^3 with an arithmetic average of 144.6 μg/m^3. The elevated PM2.5 in winter was mostly attributed to combustion sources such as vehicle exhaust, heating, cooking and industrial emissions, low wind speeds and high relative humidity （RH）, which were favorable for pollutant accumulation and formation of secondary pollutants. By chemical mass balance, it was estimated that about 89.1% of the PM2.5 mass concentrations were explained by carbonaceous species, secondary particles, crustal matters, sea salt and trace elements. Organic material was the largest contributor, accounting for about 32.7% of the total PM2.5 mass concentrations. SO4^2-, NO3^-, Cl^- and NH4^＋ were four major ions, accounting for 16.6%, 11.5%, 4.7% and 6,0%, respectively, of the total mass of PM2.5.
文摘Twenty-three progressive extractions were performed to study individual humic acids (HAs) and humin fractions from a typical black soil (Mollisol) in Heilongjiang Province, China using elemental analysis and spectroscopic techniques. After 23 HA extractions the residue was separated into high and low organic carbon humin fractions. HA yield was the highest for the first extraction and then gradually decreased with further extractions. Organic carbon (OC) of the humin fractions accounted for 58% of total OC …
基金supported by The National Natural Science Foundation of China (Grant no.20677030)The Commonweal Project of National Environment Protection (Grant no.200709013)
文摘PM2.5 samples were collected at urban, industrial and coastal sites in Tianjin during winter, spring and summer in 2007. Concentrations of elemental carbon （EC） and organic carbon （OC） were analyzed using the IMPROVE thermal-optical reflectance （TOR） method. Both OC and EC exhibited a clear seasonal pattern with higher concentrations observed in the winter than in the spring and summer, due to cooperative effect of changes in emission rates and seasonal meteorology. The concentrations of carbonaceous species were also influenced by the local factors at different sampling sites, ranking in the order of industrial〉 urban 〉 coastal during winter and spring. In the summer, the port emissions, enriched with EC, had a significant impact on carbonaceous aerosols at the coastal site. Total carbonaceous aerosol accounted for 40.0% in winter, 33.8% in spring and 31.4% in summer of PM2.5 mass. Good correlation （R = 0.84-0.93） between OC and EC indicated that they had common dominant sources of combustion such as coal burning and traffic emissions. The daily average OC/EC ratios ranged from 2.1 to 9.1, the elevated OC/EC ratios being found in the winter. The estimated secondary organic carbon （SOC） accounted for 46.9%, 35.3% and 40.2% of the total OC in the winter, spring and summer, respectively, indicating that SOC may be an important contributor to fine organic aerosol in Tianjin.
基金the National Basic Research Program (973) of China (No.2004CB418502,2003CB415002)the National Natural Science Foundation of China (No.29977002).
文摘The humic acids (HAs) isolated from the sediments of the various rivers,lakes,and reservoirs in China were studied using elemental analyzer,fourier transform infrared (FT-IR),and CP/MAS 13C nuclear magnetic resonance (NMR) spectroscopy.The results showed that the HAs were characterized by some common chemical and physicochemical properties,but they also pose some differences in the C-containing functional groups.The C/N,C/H,O/C,and O/H ratios differ widely for the various HAs,showing that the elemental comp...
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (No. KZCX2-YW-453,KZCX2-YW-JS404,KZCX2-EW-408)the Commonweal Program of Environment Protection Department of China (No. 201009004)the Program of Bureau of Science and Technology,Xiamen (No. 3502Z20081117,350205Z20095001)
文摘Xiamen, located on the southeastern coastal line of China, is undergoing rapid urbanization and industrialization, so its air quality has a trend of degradation. However, studies on level, temporal and spatial changes of fine particles （PM2.5） and their carbonaceous fractions are scarce. In this article, abundance, sources, seasonal and spatial variations, distribution of organic carbon （OC） and elemental carbon （EC） in PM2.5, were studied at suburban, urban and industrial sites in Xiamen during four season-representative months in 2009-2010. PM2.5 samples were collected with middle volume sampler and were analyzed for OC and EC with thermal optical transmittance （TOT） method. Results showed that the annual average PM2.5 concentrations were 63.88-74.80 Ixg/m3 at three sites. While OC and EC concentrations were in the range of 15.81-19.73 [xg/m3 and 2.74-3.49 ~tg/m3, respectively, and clearly presented the summer minima and winter maxima in this study. The carbonaceous aerosol accounted for 42.8%-47.3% of the mass of PMzs. The annual average of secondary organic carbon （SOC） concentrations in Xiamen were 9.23-11.36 ~g/m3, accounting for approximately 56% of OC. Strong correlations between OC and EC was found in spring （R2 = 0.50） and autumn （R2 = 0.73）, suggesting that there were similar emission and transport processes for carbonaceous aerosols in these two seasons, while weak correlations were found in summer （R2 = 0.33） and winter （R2 = 0.41）. The OCI＇EC ratios in PM2.5 varied from 2.1 to 8.7 with an annual average of 5.7, indicating that vehicle exhaust, coal smoke and biomass burning were main source apportionments of carbonaceous fractions in Xiamen.
基金This work was supported by a grant from the National Natural Science Foundation of China (No. 30370647).
文摘Background One of the major causes of death in severe acute pancreatitis （SAP） is severe infection owing to bacterial translocation. Some clinical studies suggested that ecoimmunonutrition （EIN） as a new strategy had better treatment effect on SAP patients. But the experiment studies on the precise mechanism of the effect of EIN were less reported. In this study, we mainly investigated the effects of EIN on bacterial translocation in SAP model of dogs. Methods SAP was induced by retrograde infusion of 5% sodium taurocholate into the pancreatic duct in healthy hybrid dogs. The SAP dogs were supported with either parenteral nutrition （PN） or elemental enteral nutrition （EEN） or EIN. The levels of serum amylase, serum aminotransferase and plasma endotoxin were detected before and after pancreatitis induction. On the 7th day after nutrition supports, peritoneal fluid, mesenteric lymph nodes （MLN）, liver, and pancreas were collected for bacterial culture with standard techniques to observe the incidence of bacterial translocation. Pathology changes of pancreas were analyzed by histopathologic grading and scoring of the severity of pancreas, and the degree of intestinal mucosal damage was assessed by measuring mucosal thickness, villus height, and crypt depth of ileum. Results Compared with PN and EEN, EIN significantly decreased the levels of serum amylase, serum aminotransferase, plasma endotoxin, and the incidence of bacterial translocation. Furthermore, compared with the others, the histology scores of inflammation in pancreas and the ileum injury （ileum mocosa thickness, villus height, and crypt depth） were significantly alleviated by EIN （P〈0.05）. Moreover, concerning liver function, the serum levels of alanine aminotransferase, aspartate aminotransferase and albumin were ameliorating significantly in the EIN group. Conclusion Our results suggested that EIN could maintain the integrity of intestinal mucosal barrier and reducing the incidence of bacterial translocation in SAP dogs. Ea
基金Project supported by the National Basic Research Program (973) of China (No. 2007CB407300)the National Natural Science Foundation of China (No. 40675074)+1 种基金the Pilot Project of Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX3-SW-231)a grant from the SKLLQG, Chinese Academy of Sciences and the Research Grants Council of Hong Kong (No. PolyU5145/03E, PolyU5197/05E).
文摘An intensive observation of organic carbon （OC） and element carbon （EC） in PM10 and gaseous materials （SO2, CO, and O3,） was conducted continuously to assess the characteristics of wintertime carbonaceous aerosols in an urban area of Beijing, China. Results showed that the averaged total carbon （TC） and PM10 concentrations in observation period are 30.2±120.4 and 172.6±198.3 μ/m^3 respectively. Average OC concentration in nighttime （24.9±19.6 μ/m^3 was 40% higher than that in daytime （17.7±10.9 μ/m^3. Average EC concentrations in daytime （8.8±15.2 μ/m^3 was close to that in nighttime （8.9±15.1 μ/m^3. The OC/EC ratios in nighttime ranging from 2.4 to 2.7 are higher than that in daytime ranging from 1.9 to 2.0. The concentrations of OC, EC, PM10 were low with strong winds and high with weak winds. The OC and EC were well correlated with PM10, CO and SO2, which implies they have similar sources. OC and EC were not well correlated with O3. By considering variation of OC/EC ratios in daytime and night time, correlations between OC and O3, and meteorological condition, we speculated that OC and EC in Beijing PM10 were emitted as the primary particulate form. Emission of motor vehicle with low OC/EC ratio and coal combustion sources with high OC/EC ratio are probably the dominant sources for carbonaceous aerosols in Beijing in winter. A simple method was used to estimate the relative contribution of sources to carbonaceous aerosols in Beijing PM10. Motor vehicle source accounts for 80% and 68%, while coal combustion accounts for 20% and 32% in daytime and nighttime, respectively in Beijing. Averagely, the motor vehicle and coal combustion accounted for 74% and 26%, respectively, for carbonaceous aerosols during the observation period. It points to the motor vehicle is dominant emission for carbonaceous aerosols in Beijing PM10 in winter period, which should be paid attention to control high level of PM10 in Beijing effectively.
基金This study is supported by China NSFC project(40205018)Research Grants Council of Hong Kong(BQ-500)G-V951 of the Hong Kong Polytechnic University.
文摘Concentrations and spatial distributions of organic carbon (OC) and elemental carbon (EC) in atmospheric particles were measured at 8 sites in four cities (Hong Kong, Guangzhou, Shenzhen and Zhuhai) of Pearl River Delta Region (PRDR), China during 2001 winter period and 2002 summer period. PM2.5 (particie diameter smaller than 2.5 um) and PM10 (particie diameter smaller than 10 um) samples were collected on pre-fired quartz filters with mini-volume samplers and analyzed using thermal optical reflectance (TOR) method. The average PM2.5and PM10 Ievel were 60.1 and 93.1 μg·m-3, respectively, with PM2.5 constituting 65.3% of the PM10 mass. The average OC and EC concentrations in PM2.5 were 12.0 and 5.1 μg·m-3, respectively, while those in PM10 were 16.0 and 6.5 μg·m-3, respectively. The carbo-naceous aerosol accounted for 37.2% of the PM2.5 and 32.8% of the PM10. The highest concentrations of OC and EC were observed at Guangzhou city in both vvinter and summer seasons. The average OC/EC ratios were 2.4 for PM2.5 and 2.5 for PM10, indicating the presence of secondary organic aerosols. The OC and EC in PRDR were found to be strongly correlated (correlation coefficients > 0.6), which implied that similar emission source contribute to the ambient carbon particles.
基金Project supported by the National Basic Research Program (973) of China (No. 2003CB415003)the Pilot Project of Knowledge Innovation Program of the Chinese Academy of Sciences (No. KZCX3-SW-443)the National Natural Science Foundation of China (No. 40473055).
文摘An investigation of gaseous elemental mercury concentration in atmosphere was conducted at Beijing and Guangzhou urban, Yangtze Delta regional sites and China Global Atmosphere Watch Baseline Observatory （CGAWBO） in Mt. Waliguan of remote continental area of China. High temporal resolved data were obtained using automated mercury analyzer RA-915^＋. Results showed that the overall hourly mean Hg^0 concentrations in Mt. Waliguan were 1.7±1.1 ng/m3 in summer and 0.6±0.08 ng/m^3 in winter. The concentration in Yangtze Delta regional site was 5.4±4.1 ng/m^3, which was much higher than those in Waliguan continental background area and also higher than that found in North America and Europe rural areas. In Beijing urban area the overall hourly mean Hg^0 concentrations were 8.3±3.6 ng/m^3 in winter, 6.5±5.2 ng/m^3 in spring, 4.9±3.3 ng/m^3 in summer, and 6.7±3.5 ng/m^3 in autumn, respectively, and the concentration was 13.5±7.1 ng/m^3 in Guangzhou site. The mean concentration reached the lowest value at 14：00 and the highest at 02：00 or 20：00 in all monitoring campaigns in Beijing and Guangzhou urban areas, which contrasted with the results measured in Yangtze Delta regional site and Mr. Waliguan. The features of concentration and diurnal variation of Hg^0 in Beijing and Guangzhou implied the importance of local anthropogenic sources in contributing to the high Hg^0 concentration in urban areas of China. Contrary seasonal variation patterns of Hg^0 concentration were found between urban and remote sites. In Beijing the highest Hg^0 concentration was in winter and the lowest in summer, while in Mt. Waliguan the Hg^0 concentration in summer was higher than that in winter. These indicated that different processes and factors controlled Hg^0 concentration in urban, regional and remote areas.
基金This work was partially supported by the USDA/NIFA Interagency Climate Change Grant Proposal number 2014-02114[Project number 6657-12130-002-08I,Accession number 1003011]under the Multi-Partner Call on Agricultural Greenhouse Gas Research of the FACCE-Joint Program Initiative.The German BLE and FACCE-JPI funded the German participants of the“DesignerChar4Food”(D4F)project(CK:Project No.2814ERA01A,NW-M:Project No.2814ERA02A)the Spanish colleagues(JME and TFM)were funded by FACCE-CSA no 276610/MIT04-DESIGN-UPVASC and IT-932-16,MLC thanks the Spanish Ministry of Science,Innovation and Universities,project#RTI2018-099417-B-I00+3 种基金cofinanced with EU FEDER funds and US colleagues(JN,JI and KS)were funded by The USDA-National Institute of Food and Agriculture(Project#2014-35615-21971)USDA-ARS CHARnet and GRACENet programs–D4F greatly stimulated discussions.Any opinions,findings,or recommendation expressed in this publication are those of the authors and do not necessarily reflect the view of the USDAThis work was also partially supported by the National Natural Science Foundation of China under a Grant number of 41501339,21677119,21277115,41301551,21407123,Jiangsu Province Science Foundation for Youths under a grant number of BK20140468,sponsored by Qing Lan ProjectOpen access funding provided by Natural Resources Institute Finland(LUKE).
文摘Various studies have established that feedstock choice,pyrolysis temperature,and pyrolysis type influence final biochar physicochemical characteristics.However,overarching analyses of pre-biochar creation choices and correlations to biochar characteristics are severely lacking.Thus,the objective of this work was to help researchers,biochar-stakeholders,and practitioners make more well-informed choices in terms of how these three major parameters influence the final biochar product.Utilizing approximately 5400 peer-reviewed journal articles and over 50,800 individual data points,herein we elucidate the selections that influence final biochar physical and chemical properties,total nutrient content,and perhaps more importantly tools one can use to predict biochar’s nutrient availability.Based on the large dataset collected,it appears that pyrolysis type(fast or slow)plays a minor role in biochar physico-(inorganic)chemical characteristics;few differences were evident between production styles.Pyrolysis temperature,however,affects biochar’s longevity,with pyrolysis temperatures>500℃ generally leading to longer-term(i.e.,>1000 years)half-lives.Greater pyrolysis temperatures also led to biochars containing greater overall C and specific surface area(SSA),which could promote soil physico-chemical improvements.However,based on the collected data,it appears that feedstock selection has the largest influence on biochar properties.Specific surface area is greatest in wood-based biochars,which in combination with pyrolysis temperature could likely promote greater changes in soil physical characteristics over other feedstock-based biochars.Crop-and other grass-based biochars appear to have cation exchange capacities greater than other biochars,which in combination with pyrolysis temperature could potentially lead to longer-term changes in soil nutrient retention.The collected data also suggest that one can reasonably predict the availability of various biochar nutrients(e.g.,N,P,K,Ca,Mg,Fe,and Cu)based on feedstock choi
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB15020402, XDB15020302)the Natural Science Foundation of China (41571130063, 41430858)
文摘Microorganisms are major drivers of elemental cycling in the biosphere. Determining the abundance of microbial functional traits involved in the transformation of nutrients, including carbon(C), nitrogen(N), phosphorus(P) and sulfur(S), is critical for assessing microbial functionality in elemental cycling. We developed a high-throughput quantitative-PCR-based chip, Quantitative microbial element cycling(QMEC), for assessing and quantifying the genetic potential of microbiota to mineralize soil organic matter and to release C, N, P and S. QMEC contains 72 primer pairs targeting 64 microbial functional genes for C, N, P, S and methane metabolism. These primer pairs were characterized by high coverage(average of 18–20 phyla covered per gene)and sufficient specificity(>70% match rate) with a relatively low detection limit(7–102 copies per run). QMEC was successfully applied to soil and sediment samples, identifying significantly different structures, abundances and diversities of the functional genes(P<0.05). QMEC was also able to determine absolute gene abundance. QMEC enabled the simultaneous qualitative and quantitative determination of 72 genes from 72 samples in one run, which is promising for comprehensively investigating microbially mediated ecological processes and biogeochemical cycles in various environmental contexts including those of the current global change.
基金supported by the Scientific Funds for Outstanding Young Scientists of China(No.50525619)the National Natural Science Foundation of China(No.51078163,50706014)the National High Technology Research and Development Program(863)of China(No.2006AA05Z304)
文摘Heterogeneous oxidation of gas-phase Hg 0 by nano-Fe 2 O 3 was investigated on a fixed bed reactor, and the effects of oxygen concentration, bed temperature, water vapour concentration and particle size have been discussed. The results showed that Hg 0 could be oxidized by active oxygen atom on the surface of nano-Fe 2 O 3 as well as lattice oxygen in nano-Fe 2 O 3 . Among the factors that affect Hg 0 oxidation by nano-Fe 2 O 3 , bed temperature plays an important role. More than 40% of total mercury was oxidized at 300°C, however, the test temperature at 400°C could cause sintering of nano-catalyst, which led to a lower efficiency of Hg 0 oxidation. The increase of oxygen concentration could promote mercury oxidation and led to higher Hg 0 oxidation efficiency. No obvious mercury oxidation was detected in the pure N 2 atmosphere, which indicates that oxygen is required in the gas stream for mercury oxidation. The presence of water vapour showed different effects on mercury oxidation depending on its concentration. The lower content of water vapour could promote mercury oxidation, while the higher content of water vapour inhibits mercury oxidation.
基金financially supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (Nos.KZCX2-YW-453,KZCX2-YW-JS404,and KZCX2-EW-408)the National Natural Science Foundation of China(No.41005082)the Commonweal Program of Environment Protection Department of China(No.201009004)
文摘Atmospheric fine particles （PM2.5） were collected in this study with middle volume samplers in Fuzhou, China, during both normal days and haze days in summer （September 2007） and winter （january 2008）. The concentrations, distributions, and sources of polycyclic aromatic hydrocarbons （PAHs）, organic carbon （OC）, elemental carbon （EC）, and water soluble inorganic ions （WSIls） were determinated. The results showed that the concentrations of PM2.s, PAHs, OC, EC, and WSIIs were in the orders of haze 〉 normal and winter〉 summer. The dominant PAHs of PM2.s in Fuzhou were Fluo, Pyr, Chr, BbF, BkF, BaP, BghiP, and IcdP, which represented about 80.0% of the total PAHs during different sampling periods. The BaPeq concentrations of ^-~PAHs were 0.78, 0.99, 1.22, and 2.43 ng/m3 in summer normal, summer haze, winter normal, and winter haze, respectively. Secondary pollutants （SO42 , NO3 , NH4＊, and OC） were the major chemical compositions of PM2.5, accounting for 69.0%, 55.1%, 63.4%, and 64.9% of PM2.s mass in summer normal, summer haze, winter normal, and winter haze, respectively. Correspondingly, secondary organic carbon （SOC） in Fuzhou accounted for 20.1%, 48.6%, 24.5%, and 50.5% of OC. The average values of nitrogen oxidation ratio （NOR） and sulfur oxidation ratio （SOR） were higher in haze days （0.08 and 0.27） than in normal days （0.05 and 0.22）. Higher OC/EC ratios were also found in haze days （5.0） than in normal days （3.3）. Correlation analysis demonstrated that visibility had positive correlations with wind speed, and neg- ative correlations with relative humidity and major air pollutants. Overall, the enrichments of PM2.5, OC, EC, SO42 ,andNO3 promoted haze formation. Furthermore, the diagnostic ratios of IcdP/（IcdP ＋ BghiP）, lcdP/BghiP, OC/EC, and NO3 /SO42 indicated that vehicle exhaust and coal consumption were the main sources of pollutants in Fuzhou.
文摘PM10 （particulate matter with aerodynamic diameter less than 10 μm） samples were collected simultaneously at nine urban sites and one urban background site during two intensive observation campaigns in 2006. Concentrations of elemental carbon （EC） and organic carbon （OC） in PM10 were analyzed using an element analyzer. The characteristics regarding spatial and seasonal distribution patterns of OC and EC concentrations and their contributions to PM10 mass, as well as correlation between OC and EC, were investigated in detail. The average OC and EC concentrations for urban sites were 57.5 ± 20.8 and 8.3 ± 3.9 μg/m^3, respectively, both being around three times higher than those for urban background site. As a whole, EC concentrations did not show distinct seasonal variations, though OC concentrations were generally higher in autumn than in spring. For urban sites, total carbonaceous aerosol （TCA） accounted for 33.2% in spring and 35.0% in autumn of PM10 mass. The OC and EC concentrations were found significantly correlated to each other both in spring and in autumn, implying the existence of similar emission sources such as coal combustion. The OC/EC ratios generally exceeded 2.0, indicating the presence of secondary organic carbon （SOC）, whose estimated concentration for urban Chongqing was 26.7 and 39.4μg/m^3, accounting for 48.9 and 61.9% of the total OC observed in the samples, in spring and in autumn, respectively.
文摘In 1999 aerosol samples were collected by cascade at Meteorological Tower in Beijing. The 12 group aerosol samples obtained were analyzed using PIXE method, which resulted in 20 elemental concentrations and size distribution of elemental concentrations. From the observation, the elemental concentrations, size distribution of elemental concentrations and their variations are analyzed. It shows that concentrations of the most elements in aerosols increase greatly compared with those in the past except that the concentrations of V, K, Sr, and the source of aerosols has changed greatly in the past decade. Fine mode aerosols increase more rapidly in the past decade, which may be due to the contribution of coal combustion and automobile exhaust. Pb content in aerosol is much higher than that at the beginning of 1980s, and has a decreasing trend in recent years because of using non leaded gasoline.
