Water-soluble organic matter（WSOM） represents a critical fraction of fine particles（PM2.5）in the air, but its changing behaviors and formation mechanisms are not well understood yet, partly due to the lack of fast...Water-soluble organic matter（WSOM） represents a critical fraction of fine particles（PM2.5）in the air, but its changing behaviors and formation mechanisms are not well understood yet, partly due to the lack of fast techniques for the ambient measurements. In this study,a novel system for the on-line measurement of water-soluble components in PM2.5, the particle-into-liquid sampler（PILS）–Nebulizer–aerosol chemical speciation monitor（ACSM）, was developed by combining a PILS, a nebulizer, and an ACSM. High time resolution concentrations of WSOM, sulfate, nitrate, ammonium, and chloride, as well as mass spectra, can be obtained with satisfied quality control results. The system was firstly applied in China for field measurement of WSOM. The mass spectrum of WSOM was found to resemble that of oxygenated organic aerosol, and WSOM agreed well with secondary inorganic ions. All evidence collected in the field campaign demonstrated that WSOM could be a good surrogate of secondary organic aerosol（SOA）. The PILS–Nebulizer–ACSM system can thus be a useful tool for intensive study of WSOM and SOA in PM2.5.展开更多
Labile soil organic carbon （SOC） pools, estimated through chemical fractionation techniques, are considered sensitive indicators of management-induced changes in quality and composition of soil organic matter. Altho...Labile soil organic carbon （SOC） pools, estimated through chemical fractionation techniques, are considered sensitive indicators of management-induced changes in quality and composition of soil organic matter. Although the impacts of organic manure and crop residue applications on C sequestration in rice-wheat system are fairly well documented, their influence on labile SOC pools is relatively less known. Impacts of organic manure, rice straw, and inorganic fertilizer nitrogen （N） applications on soil total organic carbon （TOC） and SOC pools including water-extractable organic C （WEOC）, hot water-soluble organic C （HWOC）, potassium permanganate- oxidizable organic C （KMnO4-C）, microbial biomass C （MBC）, mineralizable organic C （Cmin）, and the oxidizable fractions of decreasing oxidizability （easily-oxidizable, oxidizable, and weakly-oxidizable） were investigated in an ll-year field experiment under rice-wheat system. The field experiment included treatments of different combinations of farmyard manure, rice straw, and fertilizer N application rates, with C inputs estimated to be in the range from 23 to 127 Mg ha-1. After 11 years of experiment, WEOC, HWOC, and KMnO4-C were 0.32%-0.50%, 2.2%-3.3%, and 15.0%-20.6% of TOC, respectively. The easily-oxidizable, oxidizable, and weakly-oxidizable fractions were 43%-57%0, 22%-27%, and 10%-19% of TOC, respectively. The applications of farmyard manure and rice straw improved WEOC, HWOC, KMnO4-C, easily-oxidizable fraction, Cmin, and MBC, though the rates of change varied considerably from -14% to 145% and -1170 to 83% of TOC, respectively. At the C input levels between 29 and 78 Mg C ha-1 during the ll-year period, the greatest increase was observed in WEOC and the minimum in KMnO4-C. Water-extractable organic C exhibited a relatively greater sensitivity to management than TOC, suggesting that it may be used as a sensitive indicator of management-induced changes in soil organic matter under rice-wheat system. All the other labile SOC pools exhibited almost the same sensitivity to management as TOC. Most of the SOC pools investigated were positively correlated to each other though their amounts differed considerably. Long-term applications of farmyard manure and rice straw resulted in build-up of not only the labile but also the recalcitrant pool of SOC, emphasizing the need for continued application of organic amendments for permanence of the accrued C under the experimental conditions.展开更多
In recent decades, coastal ports have experienced rapid development and become an important economic and ecological hub in China. Atmospheric particle is a research hotspot in atmospheric environmental sciences in inl...In recent decades, coastal ports have experienced rapid development and become an important economic and ecological hub in China. Atmospheric particle is a research hotspot in atmospheric environmental sciences in inland regions. However, few studies on the atmospheric particle were conducted in coastal port areas in China, which indeed suffers atmospheric particle pollution. Lack of the physicochemical characteristics of fine particles serves as an obstacle toward the accurate control for air pollution in the coastal port area in China. Here, a field observation was conducted in an important coastal port city in Yangtze River Delta from March 6 to March 19, 2019. The average PM2.5 concentration was 63.7 ±27.8 μg/m^3 and NO3^-, SO4^2-, NH4^+, and organic matter accounted for ?60% of PM 2.5. Fe was the most abundant trace metal element and V as the ship emission indicator was detected. Transmission electron microscopy images showed that SK-rich, soot, Fe, SK-soot and SK-Fe were the major individual particles in the coastal port. V and soluble Fe were detected in sulfate coating of SK-Fe particles. We found that anthropogenic emissions, marine sea salt, and secondary atmosphere process were the major sources of fine particles. Backward trajectory analysis indicated that the dominant air masses were marine air mass, inland air mass from northern Zhejiang and inland-marine mixed air mass from Shandong and Shanghai during the sampling period. The findings can help us better understand the physicochemical properties of atmospheric fine particles in the coastal port of Eastern China.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
基金supported by the National Natural Science Foundation of China(Nos.U1301234,21277003)the Ministry of Science and Technology of China(No.2014BAC21B03)the Science and Technology Plan of Shenzhen Municipality
文摘Water-soluble organic matter（WSOM） represents a critical fraction of fine particles（PM2.5）in the air, but its changing behaviors and formation mechanisms are not well understood yet, partly due to the lack of fast techniques for the ambient measurements. In this study,a novel system for the on-line measurement of water-soluble components in PM2.5, the particle-into-liquid sampler（PILS）–Nebulizer–aerosol chemical speciation monitor（ACSM）, was developed by combining a PILS, a nebulizer, and an ACSM. High time resolution concentrations of WSOM, sulfate, nitrate, ammonium, and chloride, as well as mass spectra, can be obtained with satisfied quality control results. The system was firstly applied in China for field measurement of WSOM. The mass spectrum of WSOM was found to resemble that of oxygenated organic aerosol, and WSOM agreed well with secondary inorganic ions. All evidence collected in the field campaign demonstrated that WSOM could be a good surrogate of secondary organic aerosol（SOA）. The PILS–Nebulizer–ACSM system can thus be a useful tool for intensive study of WSOM and SOA in PM2.5.
基金supported by the Indian Council of Agricultural Research (ICAR) National Professor Project
文摘Labile soil organic carbon （SOC） pools, estimated through chemical fractionation techniques, are considered sensitive indicators of management-induced changes in quality and composition of soil organic matter. Although the impacts of organic manure and crop residue applications on C sequestration in rice-wheat system are fairly well documented, their influence on labile SOC pools is relatively less known. Impacts of organic manure, rice straw, and inorganic fertilizer nitrogen （N） applications on soil total organic carbon （TOC） and SOC pools including water-extractable organic C （WEOC）, hot water-soluble organic C （HWOC）, potassium permanganate- oxidizable organic C （KMnO4-C）, microbial biomass C （MBC）, mineralizable organic C （Cmin）, and the oxidizable fractions of decreasing oxidizability （easily-oxidizable, oxidizable, and weakly-oxidizable） were investigated in an ll-year field experiment under rice-wheat system. The field experiment included treatments of different combinations of farmyard manure, rice straw, and fertilizer N application rates, with C inputs estimated to be in the range from 23 to 127 Mg ha-1. After 11 years of experiment, WEOC, HWOC, and KMnO4-C were 0.32%-0.50%, 2.2%-3.3%, and 15.0%-20.6% of TOC, respectively. The easily-oxidizable, oxidizable, and weakly-oxidizable fractions were 43%-57%0, 22%-27%, and 10%-19% of TOC, respectively. The applications of farmyard manure and rice straw improved WEOC, HWOC, KMnO4-C, easily-oxidizable fraction, Cmin, and MBC, though the rates of change varied considerably from -14% to 145% and -1170 to 83% of TOC, respectively. At the C input levels between 29 and 78 Mg C ha-1 during the ll-year period, the greatest increase was observed in WEOC and the minimum in KMnO4-C. Water-extractable organic C exhibited a relatively greater sensitivity to management than TOC, suggesting that it may be used as a sensitive indicator of management-induced changes in soil organic matter under rice-wheat system. All the other labile SOC pools exhibited almost the same sensitivity to management as TOC. Most of the SOC pools investigated were positively correlated to each other though their amounts differed considerably. Long-term applications of farmyard manure and rice straw resulted in build-up of not only the labile but also the recalcitrant pool of SOC, emphasizing the need for continued application of organic amendments for permanence of the accrued C under the experimental conditions.
基金supported by the National Natural Science Foundation of China (Nos. 41805099,91844301)the China Postdoctoral Science Foundation (No. 2018M632449)the Zhejiang Provincial Natural Science Foundation of China (No. LZ19D050001)。
文摘In recent decades, coastal ports have experienced rapid development and become an important economic and ecological hub in China. Atmospheric particle is a research hotspot in atmospheric environmental sciences in inland regions. However, few studies on the atmospheric particle were conducted in coastal port areas in China, which indeed suffers atmospheric particle pollution. Lack of the physicochemical characteristics of fine particles serves as an obstacle toward the accurate control for air pollution in the coastal port area in China. Here, a field observation was conducted in an important coastal port city in Yangtze River Delta from March 6 to March 19, 2019. The average PM2.5 concentration was 63.7 ±27.8 μg/m^3 and NO3^-, SO4^2-, NH4^+, and organic matter accounted for ?60% of PM 2.5. Fe was the most abundant trace metal element and V as the ship emission indicator was detected. Transmission electron microscopy images showed that SK-rich, soot, Fe, SK-soot and SK-Fe were the major individual particles in the coastal port. V and soluble Fe were detected in sulfate coating of SK-Fe particles. We found that anthropogenic emissions, marine sea salt, and secondary atmosphere process were the major sources of fine particles. Backward trajectory analysis indicated that the dominant air masses were marine air mass, inland air mass from northern Zhejiang and inland-marine mixed air mass from Shandong and Shanghai during the sampling period. The findings can help us better understand the physicochemical properties of atmospheric fine particles in the coastal port of Eastern China.
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.
