Carbonaceous materials in seismic fault zones may considerably influence seismic fault slip;however,the formation mechanism of carbonaceous materials remains unclear.In this study,we proposed a novel hypothesis for th...Carbonaceous materials in seismic fault zones may considerably influence seismic fault slip;however,the formation mechanism of carbonaceous materials remains unclear.In this study,we proposed a novel hypothesis for the formation of carbonaceous materials in fault gouge.Thus,we conducted a CO_(2) hydrogenation experiment in a high-temperature reactor at a co-seismic temperature,with fault gouge formed during the Wenchuan earthquake as the catalyst.Our experimental results demonstrate that carbonaceous materials in fault zones are formed on the fault gouge during the chemical reaction process,suggesting that the carbonaceous materials are possibly generated from the catalytic hydrogenation of CO_(2),followed by thermal cracking of its products.The results of this study provide a theoretical basis for understanding fault behavior and earthquake physics.展开更多
Time-series of weekly total carbon （TC） concentrations of fine aerosol particles （PM2.5） in Beijing and Toronto were compared to investigate their respective levels and temporal patterns over two years from August...Time-series of weekly total carbon （TC） concentrations of fine aerosol particles （PM2.5） in Beijing and Toronto were compared to investigate their respective levels and temporal patterns over two years from August 2001 through July 2003. In addition to this comparison, differences in the factors contributing to the observed concentrations and their temporal variations are discussed. Based upon past knowledge about the two megacities with highly contrasting air pollutant levels, it is not surprising that the average TC concentration in Belling （31.5 μg C m^-3） was greater than that in Toronto by a factor of 8.3. Despite their large concentration differences, in both cities TC comprised a similarly large component of PM2.5. TC concentrations exhibited very different seasonal patterns between the two cities. In Beijing, TC experienced higher levels and greater weekly fluctuations in winter whereas in Toronto this behavior was seen in summer. As a result, the greatest gap in TC concentrations between Beijing and Toronto （by a factor of 12.7） occurred in winter, while the smallest gap （a factor of 4.6） was in summer. In Beijing, seasonal variations in the emissions probably played a greater role than meteorology in influencing the TC seasonality, while in Toronto during the warm months more than 80% of the hourly winds were recorded from the south, along with many potential anthropogenic sources for the days with high TC concentrations. This comparison of the differences provides insight into the major factors affecting carbonaceous aerosol in each city.展开更多
A series of carbonaceous mesophase spherule/activated carbon composites were prepared as anode materials for super lithium ion capacitors using carbonaceous mesophase spherules as the core materials and pitch as the a...A series of carbonaceous mesophase spherule/activated carbon composites were prepared as anode materials for super lithium ion capacitors using carbonaceous mesophase spherules as the core materials and pitch as the active carbon shell precursor.The structures of the composites were examined by scanning electron microscopy and X-ray diffractometry.The electrochemical performance was investigated in electric double layer capacitor and half-cell.The results show that,the composite exhibits good performance in both capacitor and battery with a high reversible capacity of 306.6 mA·h/g(0.2C) in the half-cell,along with a capacitance of 25.8 F/g in the capacitor when an optimum ratio of carbonaceous mesophase spherules to active carbon is adopted.The composite also shows a favorable rate performance and good cycle ability.A working model of this anode in super lithium ion capacitors was established.展开更多
Two types of mesocarbon microbeads(MCMB), one of which was green sphere and the other carbonized at 1000 ℃, were used to modify coal tar pitches, and their influences on the development of carbonaceous mesophase in c...Two types of mesocarbon microbeads(MCMB), one of which was green sphere and the other carbonized at 1000 ℃, were used to modify coal tar pitches, and their influences on the development of carbonaceous mesophase in coal tar pitches were investigated. Optical microscopy was used to observe the changes caused by the additives. The green MCMB could promote the growth of mesophase spheres. When the holding time at the final temperature was prolonged to 100 min, the green MCMB-modified pitch would produce excellent bulk mesophase. Carbonized MCMB prohibited the coalescence of mesophase spheres and was beneficial to forming super large mesophase spheres. In the green MCMB-modified pitch, mesophase spheres grew up using the added MCMB spheres as nuclei, i.e. the green MCMB continued to grow during heat-treatment, which accelerated the formation, growth, and coalescence of mesophase spheres. For carbonized MCMB, their active sites were passivated and they could not continue to grow. These inert spheres could aggregate around the newly-formed mesophase spheres, prohibiting the growth and coalescence of the mesophase spheres.展开更多
Carbonaceous materials are promising anode candidates for potassium-ion batteries(PIBs)given its high conductivity,stable property,and abundant resource,while its practical implementation is still hampered by its limi...Carbonaceous materials are promising anode candidates for potassium-ion batteries(PIBs)given its high conductivity,stable property,and abundant resource,while its practical implementation is still hampered by its limited capacity and inferior rate behavior.Herein,we report a superior carbonaceous anode through a combined strategy of carbon hybridization and heteroatom doping.In this composite,hollow carbon spindles(HCS)were anchored on the surface of graphene(G)followed with sulfur doping treatment,aiming to integrate the high conductivity of graphene,the good structure stability of HCS,and the S doping-induced ample active sites.As a PIB anode,the S-G@HCS composite can display high capacity(301 mAh g^(-1)at 0.1 A g^(-1)after 500 cycles)and long-term cyclability up to 1800 cycles at 2 A g^(-1).Impressively,it can deliver an outstanding rate capacity of 215 mAh g^(-1)at 10 A g^(-1),which is superior to most carbon anodes as-reported so far for PIBs.Experimental and theoretical analysis manifests that the construction of graphene/amorphous carbon interface as well as S doping enables the regulation of electronic structure and ion adsorption/transportation properties of carbonaceous material,thus accounting for the high capacity and superior rate capability of S-G@HCS composite.展开更多
A new carbonaceous catalyst with sulfonic acid group （-SO3H） was prepared by incomplete carbonization of β-cyclodextrin followed by sulfonation.The sulfonated amorphous carbon was characterized by IR,elemental anal...A new carbonaceous catalyst with sulfonic acid group （-SO3H） was prepared by incomplete carbonization of β-cyclodextrin followed by sulfonation.The sulfonated amorphous carbon was characterized by IR,elemental analysis,DSC-TGA and PXRD,and the catalytic activity was investigated to be an efficient catalyst for the esterification reactions with maximum yield of 87%.The sulfonated carbonaceous catalyst was readily separated from the reaction solution and keeps approximately equal catalytic activity.The results confirm that the active centre is the hydrophilic sulfonic acid functional group in the esterification reactions.展开更多
The effect of Phanerochaete chrysosporium on degradation and preg-robbing capacity of activated carbon,which was used as a substitute of carbonaceous matter in carbonaceous gold ores,was studied.After 14 d treatment w...The effect of Phanerochaete chrysosporium on degradation and preg-robbing capacity of activated carbon,which was used as a substitute of carbonaceous matter in carbonaceous gold ores,was studied.After 14 d treatment with Phanerochaete chrysosporium,the degradation rate of activated carbon reached 27.59%.The XRD and FTIR analyses indicate that Phanerochaete chrysosporium can distort the micro-crystalline structure of activated carbon,increase the number of oxygen-containing groups and aliphatics and make the aromatic structures be oxidized and exfoliated.The gold-adsorption tests show that Phanerochaete chrysosporium can reduce the preg-robbing capacity of activated carbon by 12.88%.This indicates that Phanerochaete chrysosporium is an available microorganism,and it can be employed to reduce the preg-robbing capacity of carbonaceous matter and improve the gold leaching rate.The combined effect of passivation,alkalization and oxidation of biological enzymes-free radicals of Phanerochaete chrysosporium on carbonaceous matter was also discussed.展开更多
In situ prepared mesocarbon microbead/carbon nanotube(MCMB/CNT) composites are potential precursors of high density carbon materials for various applications. Integrated MCMB/CNT composites were successfully fabricate...In situ prepared mesocarbon microbead/carbon nanotube(MCMB/CNT) composites are potential precursors of high density carbon materials for various applications. Integrated MCMB/CNT composites were successfully fabricated by hot-press sintering at 550 ℃ under 30 MPa. After further calcination at 900 ℃, the hot-press sintering fabricated MCMB block has an apparent density of 1.77 g/cm3 and the open porosity 5.1%. With the addition of 5%(mass fraction) CNTs, the density of the composite block is elevated to 1.84 g/cm3, and its open porosity is reduced to 3.5%. The flexural strength of composite block with 5% CNTs is elevated to 116 MPa. Through the hot-press sintering, pores of 10-50 nm in the calcinated bulks are remarkably eliminated. The interstice between microbeads in the composite blocks is filled up by CNTs together with β-resin and quinoline-insoluble spheres, which can further contribute to the densification.展开更多
Under the joint assistance of its excellent storage strength, accessible long storage lifespan, and high heat utilization efficiency, salt hydrate-based thermochemical heat storage(THS) materials give renewable energy...Under the joint assistance of its excellent storage strength, accessible long storage lifespan, and high heat utilization efficiency, salt hydrate-based thermochemical heat storage(THS) materials give renewable energy an important outlet to alleviate the pressure of underutilization. Herein, an activated hollow spherical carbon(AHSC) with hierarchical porous architectures converted from covalent-organic frameworks(COFs) is constructed and utilized as the supporting matrix for Li OH.THS composite material for the first time. The obtained Li/AHSC_(3) composites have distinguished hydration performance while manifesting impressive storage ability up to 1916.4 k J kg^(-1)with low operating temperature stemming from the collective effect of the void spherical framework, multimodal porosity, and high surface area of AHSC3. And the Li/AHSC3-40 composite with evidently progressed thermal conductivity is capable of realizing 94.5% heat preservation after twenty-five adsorption-desorption cycles, exhibiting its eminent cyclability and great heat transfer performance. This study not only brings new hope for overcoming the underutilization of low-grade heat but also may enlighten new ideas for enriching the application scenarios of COFs-derived carbonaceous materials.展开更多
Black carbon is one of the primary aerosols directly emitted from biomass known to have strong absorbing properties. The INDAAF and PASMU observational field campaigns which took place (2018) in Abidjan (urban area) a...Black carbon is one of the primary aerosols directly emitted from biomass known to have strong absorbing properties. The INDAAF and PASMU observational field campaigns which took place (2018) in Abidjan (urban area) and Lamto (rural area) allow the analysis of Black carbon concentration at different time scales through real-time measurements using an analyzer named Aethalometer AE-33. Results presented here show at Lamto: 1) for the diurnal scale an average of 1.71 ± 0.3 μg⋅m<sup>-3</sup> (0.34 ± 0.09 μg⋅m<sup>-3</sup>) in the dry (wet) season;2) for the monthly scale an average of 1.14 ± 0.84 μg⋅m<sup>-3</sup>;3) on the seasonal scale, an average of 2.2 ± 0.02 μg⋅m<sup>-3</sup> (0.6 ± 0.19 μg⋅m<sup>-3</sup>) in the dry (wet) season. The black carbon variation at Lamto is seasonal with an amplification factor of 85.6. Regarding the urban area of Abidjan, due to sampling issues, our analyses were limited to daily, diurnal and weekly time scales. We observed: a) at a daily scale an average of 5.31.± 2.5 μg⋅m<sup>-3</sup>, b) diurnal scale, an average ranging from 6.87 to 13.92 μg⋅m<sup>-3</sup>. The analysis indicated that emissions from urban areas are more related to social and economic activities, with weekday concentrations (7.24 μg⋅m<sup>-3</sup>) higher than concentrations over the weekend (e.g. Saturday 6.59 μg⋅m<sup>-3</sup> and Sunday 6.00 μg⋅m<sup>-3</sup>). Moreover, BC concentration in Abidjan is quite noticeable compared to that of rural areas (Lamto). The ratio between the maximum values of the two areas is of the order of 5.86. In addition, concentrations in some urban areas are slightly above the daily threshold set by the WHO (10 μg⋅m<sup>-3</sup>). Therefore, the levels of urban BC concentrations are alarming whilst rural BC concentrations remain below daily WHO thresholds and are of the same magnitude as those of West African megacities. This study underlies that BC concentrations at Lamto are mainly related to biomass combustion sources while those from urban areas are related to traffic sources. The latter is permanently active, unlike those in rural Lamto, which is seasonal.展开更多
The Indo-Gangetic Plain(IGP)is a major regional and global emitter of atmospheric pollutants,which adversely affect surrounding areas such as the Himalayas.We present a comprehensive dataset on carbonaceous aerosol(CA...The Indo-Gangetic Plain(IGP)is a major regional and global emitter of atmospheric pollutants,which adversely affect surrounding areas such as the Himalayas.We present a comprehensive dataset on carbonaceous aerosol(CA)composition,radiocarbon(D14C)-based source apportionment,and light absorption of total suspended particle(TSP)samples collected over a 3-year period from high-altitude Jomsom in the central Himalayas.The 3-year mean TSP,organic carbon(OC),and elemental carbon(EC)concentrations were 92.0±28.6,9.74±6.31,and 2.02±1.35 lg m^(3),respectively,with the highest concentrations observed during the pre-monsoon season,followed by the post-monsoon,winter,and monsoon seasons.The △^(14)C analysis revealed that the contribution of fossil fuel combustion(ffossil)to EC was 47.9%±11.5%,which is consistent with observations in urban and remote regions in South Asia and attests that EC likely arrives in Jomsom from upwind IGP sources via long-range transport.In addition,the lowest f_(fossil)(38.7%±13.3%)was observed in winter,indicating large contributions in this season from local biomass burning.The mass absorption cross-section of EC(MACEC:8.27±1.76 m^(2)/g)and watersoluble organic carbon(MACWSOC:0.98±0.45 m^(2)/g)were slightly higher and lower than those reported in urban regions,respectively,indicating that CA undergo an aging process.Organic aerosol coating during transport and variation of biomass burning probably led to the seasonal variation in MAC of two components.Overall,WSOC contributed considerably to the light absorption(11.1%±4.23%)of EC.The findings suggest that to protect glaciers of the Himalayas from pollution-related melting,it is essential to mitigate emissions from the IGP.展开更多
文摘Carbonaceous materials in seismic fault zones may considerably influence seismic fault slip;however,the formation mechanism of carbonaceous materials remains unclear.In this study,we proposed a novel hypothesis for the formation of carbonaceous materials in fault gouge.Thus,we conducted a CO_(2) hydrogenation experiment in a high-temperature reactor at a co-seismic temperature,with fault gouge formed during the Wenchuan earthquake as the catalyst.Our experimental results demonstrate that carbonaceous materials in fault zones are formed on the fault gouge during the chemical reaction process,suggesting that the carbonaceous materials are possibly generated from the catalytic hydrogenation of CO_(2),followed by thermal cracking of its products.The results of this study provide a theoretical basis for understanding fault behavior and earthquake physics.
基金funded by National Natural Science Foundation of China(NSFC)projects(Grant Nos.20322203 and 40675079)the National Science Fund for Distinguished Young Scholars of NSFC(Grant No.20625722)
文摘Time-series of weekly total carbon （TC） concentrations of fine aerosol particles （PM2.5） in Beijing and Toronto were compared to investigate their respective levels and temporal patterns over two years from August 2001 through July 2003. In addition to this comparison, differences in the factors contributing to the observed concentrations and their temporal variations are discussed. Based upon past knowledge about the two megacities with highly contrasting air pollutant levels, it is not surprising that the average TC concentration in Belling （31.5 μg C m^-3） was greater than that in Toronto by a factor of 8.3. Despite their large concentration differences, in both cities TC comprised a similarly large component of PM2.5. TC concentrations exhibited very different seasonal patterns between the two cities. In Beijing, TC experienced higher levels and greater weekly fluctuations in winter whereas in Toronto this behavior was seen in summer. As a result, the greatest gap in TC concentrations between Beijing and Toronto （by a factor of 12.7） occurred in winter, while the smallest gap （a factor of 4.6） was in summer. In Beijing, seasonal variations in the emissions probably played a greater role than meteorology in influencing the TC seasonality, while in Toronto during the warm months more than 80% of the hourly winds were recorded from the south, along with many potential anthropogenic sources for the days with high TC concentrations. This comparison of the differences provides insight into the major factors affecting carbonaceous aerosol in each city.
基金Project(2007BAE12B00) supported by the National Key Technology R&D Program of ChinaProject(50974136) supported by the National Natural Science Foundation of China
文摘A series of carbonaceous mesophase spherule/activated carbon composites were prepared as anode materials for super lithium ion capacitors using carbonaceous mesophase spherules as the core materials and pitch as the active carbon shell precursor.The structures of the composites were examined by scanning electron microscopy and X-ray diffractometry.The electrochemical performance was investigated in electric double layer capacitor and half-cell.The results show that,the composite exhibits good performance in both capacitor and battery with a high reversible capacity of 306.6 mA·h/g(0.2C) in the half-cell,along with a capacitance of 25.8 F/g in the capacitor when an optimum ratio of carbonaceous mesophase spherules to active carbon is adopted.The composite also shows a favorable rate performance and good cycle ability.A working model of this anode in super lithium ion capacitors was established.
基金National Natural Science Foundation of China (No 50172034)
文摘Two types of mesocarbon microbeads(MCMB), one of which was green sphere and the other carbonized at 1000 ℃, were used to modify coal tar pitches, and their influences on the development of carbonaceous mesophase in coal tar pitches were investigated. Optical microscopy was used to observe the changes caused by the additives. The green MCMB could promote the growth of mesophase spheres. When the holding time at the final temperature was prolonged to 100 min, the green MCMB-modified pitch would produce excellent bulk mesophase. Carbonized MCMB prohibited the coalescence of mesophase spheres and was beneficial to forming super large mesophase spheres. In the green MCMB-modified pitch, mesophase spheres grew up using the added MCMB spheres as nuclei, i.e. the green MCMB continued to grow during heat-treatment, which accelerated the formation, growth, and coalescence of mesophase spheres. For carbonized MCMB, their active sites were passivated and they could not continue to grow. These inert spheres could aggregate around the newly-formed mesophase spheres, prohibiting the growth and coalescence of the mesophase spheres.
基金supported by National Natural Science Foundation of China(Grant 61935017,21701174,21771182)Projects of International Cooperation and Exchanges NSFC(Grant 51811530018)+2 种基金Synergetic Innovation Center for Organic Electronics and Information Displaysthe Youth Innovation Promotion Associa tion CASthe start-up funding from FJNU。
文摘Carbonaceous materials are promising anode candidates for potassium-ion batteries(PIBs)given its high conductivity,stable property,and abundant resource,while its practical implementation is still hampered by its limited capacity and inferior rate behavior.Herein,we report a superior carbonaceous anode through a combined strategy of carbon hybridization and heteroatom doping.In this composite,hollow carbon spindles(HCS)were anchored on the surface of graphene(G)followed with sulfur doping treatment,aiming to integrate the high conductivity of graphene,the good structure stability of HCS,and the S doping-induced ample active sites.As a PIB anode,the S-G@HCS composite can display high capacity(301 mAh g^(-1)at 0.1 A g^(-1)after 500 cycles)and long-term cyclability up to 1800 cycles at 2 A g^(-1).Impressively,it can deliver an outstanding rate capacity of 215 mAh g^(-1)at 10 A g^(-1),which is superior to most carbon anodes as-reported so far for PIBs.Experimental and theoretical analysis manifests that the construction of graphene/amorphous carbon interface as well as S doping enables the regulation of electronic structure and ion adsorption/transportation properties of carbonaceous material,thus accounting for the high capacity and superior rate capability of S-G@HCS composite.
基金Funded by the Guangdong Science Project (No.2008B011000015)
文摘A new carbonaceous catalyst with sulfonic acid group （-SO3H） was prepared by incomplete carbonization of β-cyclodextrin followed by sulfonation.The sulfonated amorphous carbon was characterized by IR,elemental analysis,DSC-TGA and PXRD,and the catalytic activity was investigated to be an efficient catalyst for the esterification reactions with maximum yield of 87%.The sulfonated carbonaceous catalyst was readily separated from the reaction solution and keeps approximately equal catalytic activity.The results confirm that the active centre is the hydrophilic sulfonic acid functional group in the esterification reactions.
基金Projects (51174062,51104036) supported by the National Natural Science Foundation of ChinaProject (2012AA061502) supported by the National Hi-tech Research and Development Program of China+1 种基金Project (2012BAE06B05) supported by the National Science and Technology Support Program of China during the 12th Five-Year Plan PeriodProjects (N120602006,N110302002,N110602005) supported by Fundamental Research Funds for the Central Universities of China
文摘The effect of Phanerochaete chrysosporium on degradation and preg-robbing capacity of activated carbon,which was used as a substitute of carbonaceous matter in carbonaceous gold ores,was studied.After 14 d treatment with Phanerochaete chrysosporium,the degradation rate of activated carbon reached 27.59%.The XRD and FTIR analyses indicate that Phanerochaete chrysosporium can distort the micro-crystalline structure of activated carbon,increase the number of oxygen-containing groups and aliphatics and make the aromatic structures be oxidized and exfoliated.The gold-adsorption tests show that Phanerochaete chrysosporium can reduce the preg-robbing capacity of activated carbon by 12.88%.This indicates that Phanerochaete chrysosporium is an available microorganism,and it can be employed to reduce the preg-robbing capacity of carbonaceous matter and improve the gold leaching rate.The combined effect of passivation,alkalization and oxidation of biological enzymes-free radicals of Phanerochaete chrysosporium on carbonaceous matter was also discussed.
基金Project(10332020) supported by the National Natural Science Foundation of China
文摘In situ prepared mesocarbon microbead/carbon nanotube(MCMB/CNT) composites are potential precursors of high density carbon materials for various applications. Integrated MCMB/CNT composites were successfully fabricated by hot-press sintering at 550 ℃ under 30 MPa. After further calcination at 900 ℃, the hot-press sintering fabricated MCMB block has an apparent density of 1.77 g/cm3 and the open porosity 5.1%. With the addition of 5%(mass fraction) CNTs, the density of the composite block is elevated to 1.84 g/cm3, and its open porosity is reduced to 3.5%. The flexural strength of composite block with 5% CNTs is elevated to 116 MPa. Through the hot-press sintering, pores of 10-50 nm in the calcinated bulks are remarkably eliminated. The interstice between microbeads in the composite blocks is filled up by CNTs together with β-resin and quinoline-insoluble spheres, which can further contribute to the densification.
基金the support from the Key-Area Research and Development Program of Guangdong Province (2020B0202010004)the National Natural Science Foundation of China (52071192)the Key Research Program of Frontier Sciences, CAS (QYZDY-SSW-JSC038)。
文摘Under the joint assistance of its excellent storage strength, accessible long storage lifespan, and high heat utilization efficiency, salt hydrate-based thermochemical heat storage(THS) materials give renewable energy an important outlet to alleviate the pressure of underutilization. Herein, an activated hollow spherical carbon(AHSC) with hierarchical porous architectures converted from covalent-organic frameworks(COFs) is constructed and utilized as the supporting matrix for Li OH.THS composite material for the first time. The obtained Li/AHSC_(3) composites have distinguished hydration performance while manifesting impressive storage ability up to 1916.4 k J kg^(-1)with low operating temperature stemming from the collective effect of the void spherical framework, multimodal porosity, and high surface area of AHSC3. And the Li/AHSC3-40 composite with evidently progressed thermal conductivity is capable of realizing 94.5% heat preservation after twenty-five adsorption-desorption cycles, exhibiting its eminent cyclability and great heat transfer performance. This study not only brings new hope for overcoming the underutilization of low-grade heat but also may enlighten new ideas for enriching the application scenarios of COFs-derived carbonaceous materials.
文摘Black carbon is one of the primary aerosols directly emitted from biomass known to have strong absorbing properties. The INDAAF and PASMU observational field campaigns which took place (2018) in Abidjan (urban area) and Lamto (rural area) allow the analysis of Black carbon concentration at different time scales through real-time measurements using an analyzer named Aethalometer AE-33. Results presented here show at Lamto: 1) for the diurnal scale an average of 1.71 ± 0.3 μg⋅m<sup>-3</sup> (0.34 ± 0.09 μg⋅m<sup>-3</sup>) in the dry (wet) season;2) for the monthly scale an average of 1.14 ± 0.84 μg⋅m<sup>-3</sup>;3) on the seasonal scale, an average of 2.2 ± 0.02 μg⋅m<sup>-3</sup> (0.6 ± 0.19 μg⋅m<sup>-3</sup>) in the dry (wet) season. The black carbon variation at Lamto is seasonal with an amplification factor of 85.6. Regarding the urban area of Abidjan, due to sampling issues, our analyses were limited to daily, diurnal and weekly time scales. We observed: a) at a daily scale an average of 5.31.± 2.5 μg⋅m<sup>-3</sup>, b) diurnal scale, an average ranging from 6.87 to 13.92 μg⋅m<sup>-3</sup>. The analysis indicated that emissions from urban areas are more related to social and economic activities, with weekday concentrations (7.24 μg⋅m<sup>-3</sup>) higher than concentrations over the weekend (e.g. Saturday 6.59 μg⋅m<sup>-3</sup> and Sunday 6.00 μg⋅m<sup>-3</sup>). Moreover, BC concentration in Abidjan is quite noticeable compared to that of rural areas (Lamto). The ratio between the maximum values of the two areas is of the order of 5.86. In addition, concentrations in some urban areas are slightly above the daily threshold set by the WHO (10 μg⋅m<sup>-3</sup>). Therefore, the levels of urban BC concentrations are alarming whilst rural BC concentrations remain below daily WHO thresholds and are of the same magnitude as those of West African megacities. This study underlies that BC concentrations at Lamto are mainly related to biomass combustion sources while those from urban areas are related to traffic sources. The latter is permanently active, unlike those in rural Lamto, which is seasonal.
基金Projects(52278439, 51908073, 51838001, 52078066) supported by the National Natural Science Foundation of ChinaProject(21B0317) supported by the Hunan Province Education Department, China+1 种基金Project(KFJ170302) supported by the Key Laboratory of Road Structure and Material Transportation Industry, Changsha University of Science & Technology, ChinaProject(CX20220892) supported by the Postgraduate Research Innovation of Hunan Province, China。
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(2019QZKK0605)Pan-Third Pole Environment Study for a Green Silk Road(Pan-TPE)(XDA20040501)+3 种基金the National Natural Science Foundation of China(41705132,41630754)the State Key Laboratory of Cryospheric Science(SKLCS-ZZ-2022)the Asia-Pacific Network for Global Change Research(APN)(CRECS2020-07MY-Tripathee)as well as the Swedish Research Council VR Distinguished Professorship grant toÖ.Gustafsson(no.2017-01601).
文摘The Indo-Gangetic Plain(IGP)is a major regional and global emitter of atmospheric pollutants,which adversely affect surrounding areas such as the Himalayas.We present a comprehensive dataset on carbonaceous aerosol(CA)composition,radiocarbon(D14C)-based source apportionment,and light absorption of total suspended particle(TSP)samples collected over a 3-year period from high-altitude Jomsom in the central Himalayas.The 3-year mean TSP,organic carbon(OC),and elemental carbon(EC)concentrations were 92.0±28.6,9.74±6.31,and 2.02±1.35 lg m^(3),respectively,with the highest concentrations observed during the pre-monsoon season,followed by the post-monsoon,winter,and monsoon seasons.The △^(14)C analysis revealed that the contribution of fossil fuel combustion(ffossil)to EC was 47.9%±11.5%,which is consistent with observations in urban and remote regions in South Asia and attests that EC likely arrives in Jomsom from upwind IGP sources via long-range transport.In addition,the lowest f_(fossil)(38.7%±13.3%)was observed in winter,indicating large contributions in this season from local biomass burning.The mass absorption cross-section of EC(MACEC:8.27±1.76 m^(2)/g)and watersoluble organic carbon(MACWSOC:0.98±0.45 m^(2)/g)were slightly higher and lower than those reported in urban regions,respectively,indicating that CA undergo an aging process.Organic aerosol coating during transport and variation of biomass burning probably led to the seasonal variation in MAC of two components.Overall,WSOC contributed considerably to the light absorption(11.1%±4.23%)of EC.The findings suggest that to protect glaciers of the Himalayas from pollution-related melting,it is essential to mitigate emissions from the IGP.
