Guangzhou Institute of Geochemistry

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    22261 research outputs found

    Biogenic emission as a potential source of atmospheric aromatic hydrocarbons: Insights from a cyanobacterial bloom-occurring eutrophic lake

    No full text
    As important precursors of ozone (O3 ) and secondary organic aerosol (SOA), reactive aromatic hydrocarbons (AHs) have typically been classified as anthropogenic air pollutants. However, biogenic emission can also be a potential source of atmospheric AHs. Herein, field observations in a eutrophic lake were combined with laboratory incubation experiments to investigate the biogenic AH emission. Field work showed that the water-air fluxes of AHs measured at sites with high cyanobacteria abundance could reach an order of magnitude greater than those at sites with low cyanobacteria abundance, suggesting that cyanobacteria could be the important contributor to measured AHs. Laboratory incubation experiments further confirmed the AH emission of cyanobacteria and revealed that the emission could change significantly over the lifespan of cyanobacteria and varied to their growing conditions. By combining field observations and laboratory incubation experiments, it has been suggested that the emission of different AH species from cyanobacteria could be modulated by variable biogeochemical mechanisms and that the biochemical process of toluene could be different from that of other AHs. This study investigates AH emissions from inland aquatic ecosystem and suggests that biogenic emission could be a potential source of atmospheric AHs. (c) 2024 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V

    On using an aerosol thermodynamic model to calculate aerosol acidity of coarse particles

    No full text
    Thermodynamic modeling is still the most widely used method to characterize aerosol acidity, a critical physicochemical property of atmospheric aerosols. However, it remain unclear whether gas-aerosol partitioning should be incorporated when thermodynamic models are employed to estimate the acidity of coarse particles. In this work, field measurements were conducted at a coastal city in northem China across three seasons, and covered wide ranges of temperature, relative humidity and NH3 concentrations. We examined the performance of different modes of ISORROPIA-II (a widely used aerosol thermodynamic model) in estimating aerosol acidity of coarse and fine particles. The M0 mode, which incorporates gas-phase data and runs the model in the forward mode, provided reasonable estimation of aerosol acidity for coarse and fine particles. Compared to M0, the M1 mode, which runs the model in the forward mode but does not include gas-phase data, may capture the general trend of aerosol acidity but underestimates pH for both coarse and fine particles; M2, which runs the model in the reverse mode, results in large errors in estimated aerosol pH for both coarse and fine particles and should not be used for aerosol acidity calculations. However, M1 significantly underestimates liquid water contents for both fine and coarse particles, while M2 provides reliable estimation of liquid water contents. In summary, our work highlights the importance of incorporating gas -aerosol partitioning when estimating coarse particle acidity, and thus may help improve our understanding of acidity of coarse particles. (c) 2024 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V

    On using an aerosol thermodynamic model to calculate aerosol acidity of coarse particles

    No full text
    Thermodynamic modeling is still the most widely used method to characterize aerosol acidity, a critical physicochemical property of atmospheric aerosols. However, it remain unclear whether gas-aerosol partitioning should be incorporated when thermodynamic models are employed to estimate the acidity of coarse particles. In this work, field measurements were conducted at a coastal city in northem China across three seasons, and covered wide ranges of temperature, relative humidity and NH3 concentrations. We examined the performance of different modes of ISORROPIA-II (a widely used aerosol thermodynamic model) in estimating aerosol acidity of coarse and fine particles. The M0 mode, which incorporates gas-phase data and runs the model in the forward mode, provided reasonable estimation of aerosol acidity for coarse and fine particles. Compared to M0, the M1 mode, which runs the model in the forward mode but does not include gas-phase data, may capture the general trend of aerosol acidity but underestimates pH for both coarse and fine particles; M2, which runs the model in the reverse mode, results in large errors in estimated aerosol pH for both coarse and fine particles and should not be used for aerosol acidity calculations. However, M1 significantly underestimates liquid water contents for both fine and coarse particles, while M2 provides reliable estimation of liquid water contents. In summary, our work highlights the importance of incorporating gas -aerosol partitioning when estimating coarse particle acidity, and thus may help improve our understanding of acidity of coarse particles. (c) 2024 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V

    A comparative study on the formation of nitrogen-containing organic compounds in cloudd roplets and aerosolp articles

    No full text
    Nitrogen-containing organic compounds (NOCs)maypotentiallycontributetoaqueoussec-ondaryorganicaerosols,yet the different formationofNOCsinaerosolparticlesand clouddropletsremainsunclear. With the in-situmeasurementsperformedatamountainsite(1690ma.s.l.)in southernChina,weinvestigatedtheformationofNOCsintheclouddropletsandthecloud-freeparticles,basedontheirmixingstateinformationofNOCs-containingparticlesbysingleparticlemassspectrometry.TherelativeabundanceofNOCsinthecloud-freeparticleswassignificantlyhigherthanthoseincloudresidual(cloudRES)particles.NOCswerehighlycorrelatedwithcarbonylcompounds(includingglyoxalateandmethylglyoxal)inthecloud-freeparticles,however,limitedcorrelationwasobservedforcloudRESparticles.AnalysisoftheirmixingstateandtemporalvariationshighlightsthatNOCswasmainlyformedfromthecarbonylcompoundsandammoniuminthecloud-freeparticles,ratherthaninthecloud RES particles.Theresultssupportthattheformation of NOCsfromcarbonylcompoundsisfacilitatedinconcentratedsolutionsinwetaerosols,ratherthanclouddroplets.In addition,we have identified the transport of biomass burnin

    Meteorological effects on sources and future projection of nitrogen deposition to lakes in China

    No full text
    Lake ecosystems are extremely sensitive to nitrogen growth, which leads to water quality degradation and ecosystem health decline. Nitrogen depositions, as one of the main sources of nitrogen in water, are expected to change under future climate change scenarios. However, it remains not clear how nitrogen deposition to lakes respond to future meteorological conditions. In this study, a source-oriented version of Community Multiscale Air Quality (CMAQ) Model was used to estimate nitrogen deposition to 263 lakes in 2013 and under three RCP scenarios (4.5, 6.0 and 8.5) in 2046. Annual total deposition of 58.2 Gg nitrogen was predicted for all lakes, with 23.3 Gg N by wet deposition and 34.9 Gg N by dry deposition. Nitrate and ammonium in aerosol phase are the major forms of wet deposition, while NH 3 and HNO 3 in gas phase are the major forms of dry deposition. Agriculture emissions contribute to 57% of wet deposition and 44% of dry deposition. Under future meteorological conditions, wet deposition is predicted to increase by 5.5% to 16.4%, while dry deposition would decrease by 0.3% to 13.0%. Changes in wind speed, temperature, relative humidity (RH), and precipitation rates are correlated with dry and wet deposition changes. The predicted changes in deposition to lakes driven by meteorological changes can lead to significant changes in aquatic chemistry and ecosystem functions. Apart from future emission scenarios, different climate scenarios should be considered in future ecosystem health evaluation in response to nitrogen deposition. (c) 2024 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V

    Biogenic emission as a potential source of atmospheric aromatic hydrocarbons: Insights from a cyanobacterial bloom-occurring eutrophic lake

    No full text
    As important precursors of ozone (O3 ) and secondary organic aerosol (SOA), reactive aromatic hydrocarbons (AHs) have typically been classified as anthropogenic air pollutants. However, biogenic emission can also be a potential source of atmospheric AHs. Herein, field observations in a eutrophic lake were combined with laboratory incubation experiments to investigate the biogenic AH emission. Field work showed that the water-air fluxes of AHs measured at sites with high cyanobacteria abundance could reach an order of magnitude greater than those at sites with low cyanobacteria abundance, suggesting that cyanobacteria could be the important contributor to measured AHs. Laboratory incubation experiments further confirmed the AH emission of cyanobacteria and revealed that the emission could change significantly over the lifespan of cyanobacteria and varied to their growing conditions. By combining field observations and laboratory incubation experiments, it has been suggested that the emission of different AH species from cyanobacteria could be modulated by variable biogeochemical mechanisms and that the biochemical process of toluene could be different from that of other AHs. This study investigates AH emissions from inland aquatic ecosystem and suggests that biogenic emission could be a potential source of atmospheric AHs. (c) 2024 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V

    Meteorological effects on sources and future projection of nitrogen deposition to lakes in China

    No full text
    Lake ecosystems are extremely sensitive to nitrogen growth, which leads to water quality degradation and ecosystem health decline. Nitrogen depositions, as one of the main sources of nitrogen in water, are expected to change under future climate change scenarios. However, it remains not clear how nitrogen deposition to lakes respond to future meteorological conditions. In this study, a source-oriented version of Community Multiscale Air Quality (CMAQ) Model was used to estimate nitrogen deposition to 263 lakes in 2013 and under three RCP scenarios (4.5, 6.0 and 8.5) in 2046. Annual total deposition of 58.2 Gg nitrogen was predicted for all lakes, with 23.3 Gg N by wet deposition and 34.9 Gg N by dry deposition. Nitrate and ammonium in aerosol phase are the major forms of wet deposition, while NH 3 and HNO 3 in gas phase are the major forms of dry deposition. Agriculture emissions contribute to 57% of wet deposition and 44% of dry deposition. Under future meteorological conditions, wet deposition is predicted to increase by 5.5% to 16.4%, while dry deposition would decrease by 0.3% to 13.0%. Changes in wind speed, temperature, relative humidity (RH), and precipitation rates are correlated with dry and wet deposition changes. The predicted changes in deposition to lakes driven by meteorological changes can lead to significant changes in aquatic chemistry and ecosystem functions. Apart from future emission scenarios, different climate scenarios should be considered in future ecosystem health evaluation in response to nitrogen deposition. (c) 2024 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V

    A water probe for direct pH measurement of individual particles via micro-Raman spectroscopy

    No full text
    The acidity of atmospheric aerosols influences fundamental physicochemical processes that affect climate and human health. We recently developed a novel and facile water-probebased method for directly measuring of the pH for micrometer-size droplets, providing a promising technique to better understand aerosol acidity in the atmosphere. The complex chemical composition of fine particles in the ambient air, however, poses certain challenges to using a water-probe for pH measurement, including interference from interactions between compositions and the influence of similar compositions on water structure. To explore the universality of our method, it was employed to measure the pH of ammonium, nitrate, carbonate, sulfate, and chloride particles. The pH of particles covering a broad range (0-14) were accurately determined, thereby demonstrating that our method can be generally applied, even to alkaline particles. Furthermore, a standard spectral library was developed by integrating the standard spectra of common hydrated ions extracted through the waterprobe. The library can be employed to identify particle composition and overcome the spectral overlap problem resulting from similar effects. Using the spectral library, all ions were identified and their concentrations were determined, in tum allowing successful pH measurement of multicomponent (ammonium-sulfate-nitrate-chloride) particles. Insights into the synergistic effect of Cl-, NO3 -, and NH4 + depletion obtained with our approach revealed the interplay between pH and volatile partitioning. Given the ubiquity of component partitioning and pH variation in particles, the water probe may provide a new perspective on the underlying mechanisms of aerosol aging and aerosol-cloud interaction. (c) 2024 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V

    A comparative study on the formation of nitrogen-containing organic compounds in cloudd roplets and aerosolp articles

    No full text
    Nitrogen-containing organic compounds (NOCs)maypotentiallycontributetoaqueoussec-ondaryorganicaerosols,yet the different formationofNOCsinaerosolparticlesand clouddropletsremainsunclear. With the in-situmeasurementsperformedatamountainsite(1690ma.s.l.)in southernChina,weinvestigatedtheformationofNOCsintheclouddropletsandthecloud-freeparticles,basedontheirmixingstateinformationofNOCs-containingparticlesbysingleparticlemassspectrometry.TherelativeabundanceofNOCsinthecloud-freeparticleswassignificantlyhigherthanthoseincloudresidual(cloudRES)particles.NOCswerehighlycorrelatedwithcarbonylcompounds(includingglyoxalateandmethylglyoxal)inthecloud-freeparticles,however,limitedcorrelationwasobservedforcloudRESparticles.AnalysisoftheirmixingstateandtemporalvariationshighlightsthatNOCswasmainlyformedfromthecarbonylcompoundsandammoniuminthecloud-freeparticles,ratherthaninthecloud RES particles.Theresultssupportthattheformation of NOCsfromcarbonylcompoundsisfacilitatedinconcentratedsolutionsinwetaerosols,ratherthanclouddroplets.In addition,we have identified the transport of biomass burnin

    A water probe for direct pH measurement of individual particles via micro-Raman spectroscopy

    No full text
    The acidity of atmospheric aerosols influences fundamental physicochemical processes that affect climate and human health. We recently developed a novel and facile water-probebased method for directly measuring of the pH for micrometer-size droplets, providing a promising technique to better understand aerosol acidity in the atmosphere. The complex chemical composition of fine particles in the ambient air, however, poses certain challenges to using a water-probe for pH measurement, including interference from interactions between compositions and the influence of similar compositions on water structure. To explore the universality of our method, it was employed to measure the pH of ammonium, nitrate, carbonate, sulfate, and chloride particles. The pH of particles covering a broad range (0-14) were accurately determined, thereby demonstrating that our method can be generally applied, even to alkaline particles. Furthermore, a standard spectral library was developed by integrating the standard spectra of common hydrated ions extracted through the waterprobe. The library can be employed to identify particle composition and overcome the spectral overlap problem resulting from similar effects. Using the spectral library, all ions were identified and their concentrations were determined, in tum allowing successful pH measurement of multicomponent (ammonium-sulfate-nitrate-chloride) particles. Insights into the synergistic effect of Cl-, NO3 -, and NH4 + depletion obtained with our approach revealed the interplay between pH and volatile partitioning. Given the ubiquity of component partitioning and pH variation in particles, the water probe may provide a new perspective on the underlying mechanisms of aerosol aging and aerosol-cloud interaction. (c) 2024 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V

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    Institutional Repository of Guangzhou Institute of Geochemistry,CAS(GIGCAS OpenIR) is based in China
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