The Experts below are selected from a list of 182724 Experts worldwide ranked by ideXlab platform

Sonya Collier - One of the best experts on this subject based on the ideXlab platform.

  • Measurement Report ccn activity and its variation with organic oxidation level and volatility observed during aerosol life cycle intensive operational period alc iop
    Atmospheric Chemistry and Physics, 2021
    Co-Authors: Fan Mei, Jian Wang, Shan Zhou, Qi Zhang, Sonya Collier
    Abstract:

    Abstract. Cloud condensation nuclei (CCN) spectrum and the CCN activated fraction of size selected aerosols (SR-CCN) were measured at a rural site on Long Island during the Department of Energy (DOE) Aerosol Life Cycle Intensive Operational Period (ALC-IOP) from July 15 to August 15, 2011. During the last week of the ALC-IOP, the dependence of the activated fraction on aerosol volatility was characterized by sampling downstream of a thermodenuder operated at temperatures up to 100 ⁰C. Here we present aerosol properties, including aerosol total number concentration, CCN spectrum, and the CCN hygroscopicity for air masses of representative origins during the ALC-IOP. The hygroscopicity of organic species in the aerosol is derived from CCN hygroscopicity and chemical composition. The dependence of organic hygroscopicity on the organic oxidation level (e.g., atomic O:C ratio) agrees well with theoretical predictions and results from previous laboratory and field studies. The derived κorg and O:C ratio first increase as thermal denuder (TD) temperature increases from 20 ℃ (i.e., ambient temperature) to 50 or 75 ℃, then decreases as TD temperature further increases to 100 ℃. These trends are different from previous laboratory experiments and field observations, which Reported that organic O:C increased monotonically with increasing TD temperature, whereas κorg decreased with the TD temperature. The initial increases of O:C and κorg with TD temperature below 50 ℃ are likely due to the evaporation of more volatile organics with relatively lower O:C and hygroscopicity such as primary OA. Previous studies were either focused on laboratory-generated SOA or based on field observations at locations dominated by SOA.

Qiyuan Wang - One of the best experts on this subject based on the ideXlab platform.

  • Measurement Report quantifying source contribution of fossil fuels and biomass burning black carbon aerosol in the southeastern margin of the tibetan plateau
    Atmospheric Chemistry and Physics, 2021
    Co-Authors: Huikun Liu, Qiyuan Wang, Yong Zhang, Weikang Ran, Li Xing, Ting Zhang, Junji Cao
    Abstract:

    Abstract. Anthropogenic emissions of black carbon (BC) aerosol are transported from Southeast Asia to the southwestern Tibetan Plateau (TP) during the pre-monsoon; however, the quantities of BC from different anthropogenic sources and the transport mechanisms are still not well constrained because there have been no high-time-resolution BC source apportionments. Intensive Measurements were taken in a transport channel for pollutants from Southeast Asia to the southeastern margin of the TP during the pre-monsoon to investigate the influences of fossil fuels and biomass burning on BC. A receptor model that coupled multi-wavelength absorption with aerosol species concentrations was used to retrieve site-specific Angstrom exponents (AAEs) and mass absorption cross sections (MACs) for BC. An “aethalometer model” that used those values showed that biomass burning had a larger contribution to BC mass than fossil fuels (BC biomass=57  % versus BC fossil=43  %). The potential source contribution function indicated that BC biomass was transported to the site from northeastern India and northern Burma. The Weather Research and Forecasting model coupled with chemistry (WRF-Chem) indicated that 40 % of BC biomass originated from Southeast Asia, while the high BC fossil was transported from the southwest of the sampling site. A radiative transfer model indicated that the average atmospheric direct radiative effect (DRE) of BC was + 4.6  ±  2.4 W m −2 , with + 2.5  ±  1.8 W m −2 from BC biomass and + 2.1  ±  0.9 W m −2 from BC fossil . The DRE of BC biomass and BC fossil produced heating rates of 0.07  ±  0.05 and 0.06  ±  0.02 K d −1 , respectively. This study provides insights into sources of BC over a transport channel to the southeastern TP and the influence of the cross-border transportation of biomass-burning emissions from Southeast Asia during the pre-monsoon.

  • Measurement Report source and mixing state of black carbon aerosol in the north china plain implications for radiative effect
    Atmospheric Chemistry and Physics, 2020
    Co-Authors: Qiyuan Wang, Jiamao Zhou, Wenting Dai, Huikun Liu, Yong Zhang, Renjian Zhang, Jie Tian, Yang Chen, Weikang Ran
    Abstract:

    Abstract. Establishment of the sources and mixing state of black carbon (BC) aerosol is essential for assessing its impact on air quality and climatic effects. A winter campaign (December 2017–January 2018) was performed in the North China Plain (NCP) to evaluate the sources, coating composition, and radiative effects of BC under the background of emission reduction. Results showed that the sources of liquid fossil fuels (i.e., traffic emissions) and solid fuels (i.e., biomass and coal burning) contributed 69 % and 31 % to the total equivalent BC (eBC) mass, respectively. These values were arrived at by using a combination of multi-wavelength optical approach with the source-based aerosol absorption Angstrom exponent values. The air quality model indicated that local emissions were the dominant contributors to BC at the Measurement site. However, regional emissions from NCP were a critical factor for high BC pollution. A single-particle aerosol mass spectrometer identified six classes of elemental carbon (EC)-containing particles. They included EC coated by organic carbon and sulfate (52 % of total EC-containing particles); EC coated by Na and K (24 %); EC coated by K, sulfate, and nitrate (17 %); EC associated with biomass burning (6 %); pure-EC (1 %); and others (1 %). Different BC sources exhibited distinct impacts on the EC-containing particles. A radiative transfer model showed that the amount of detected eBC can produce an atmospheric direct radiative effect of +18.0  W m −2 and a heating rate of 0.5 K d −1 . This study shows that reductions of solid fuel combustion-related BC may be an effective way of mitigating regional warming in the NCP.

  • Measurement Report evaluation of sources and mixing state of black carbon aerosol under the background of emission reduction in the north china plain implications for radiative effect
    Atmospheric Chemistry and Physics, 2020
    Co-Authors: Qiyuan Wang, Jiamao Zhou, Yong Zhang, Renjian Zhang, Jie Tian, Yang Chen, Li Li, Jianhuai Ye, Yunfei Wu
    Abstract:

    Abstract. Accurate understanding of sources and mixing state of black carbon (BC) aerosol is essential for assessing its impacts on air quality and climatic effect. Here, a winter campaign (December 2017–January 2018) was conducted in the North China Plain (NCP) to evaluate the sources, coating composition, and radiative effect of BC under the background of emission reduction since 2013. Results show that liquid fossil fuel source (i.e., traffic emission) and solid fuel source (i.e., biomass and coal burning) contributed 69 % and 31 % to the total BC mass, respectively, using a multiwavelength optical approach combined with the source-based aerosol absorption Angstrom exponent values. The air quality model indicates that local emission was the dominant contributor to BC at the Measurement site on average, however, emissions in the NCP exerted a critical role for high BC episode. Six classes of BC-containing particles were identified, including (1) BC coated by organic carbon and sulphate (52 % of total BC-containing particles), (2) BC coated by Na and K (24 %), (3) BC coated by K, sulphate, and nitrate (17 %), (4) BC associated with biomass burning (6 %), (5) Pure-BC (1 %), and (6) others (1 %). Different BC sources had distinct impacts on those BC-containing particles. A radiative transfer model estimated that the amount of BC detected can produce an atmospheric forcing of +18.0 W m−2 and a heating rate of 0.5 K day−1. Results presented herein highlight that further reduction of solid fuel combustion-related BC may be a more effective way to mitigate regional warming in the NCP, although larger BC contribution was from liquid fossil fuel source.

  • Measurement Report quantifying source contribution and radiative forcing of fossil fuel and biomass burning black carbon aerosol in the southeastern margin of tibetan plateau
    Atmospheric Chemistry and Physics, 2020
    Co-Authors: Qiyuan Wang, Yong Zhang, Li Xing, Ting Zhang
    Abstract:

    Abstract. Black carbon (BC) aerosol plays a vital role in disturbing the balance of ecosystem and climate stability of Tibetan Plateau (TP). An intensive campaign was carried out from 14th March to 12th May 2018 in the southeastern margin of TP to investigate the sources of BC and their radiative effects. To do so, an improved aethalometer model was used to distinguish and apportion BC into fossil fuel combustion source and biomass burning source. To minimize the uncertainty associated with the aethalometer model , a receptor model coupling multi-wavelength absorption with chemical species was used to retrieve the site-dependent Angstrom exponent (AAE) and BC mass absorption cross-section (MAC). The results show that the AAEs and BC MACs at wavelength of 880 nm were 0.9 and 12.3 m2 g−1 for fossil fuel source and 1.7 and 10.4 m2 g−1 for biomass burning, respectively. Based on these parameters, the fossil fuel source-related BC (BCfossil) was estimated 43 % of the total BC and the rest 57 % was from biomass burning (BCbiomass) during the campaign. The results from a regional chemical dynamical model reveal that high BCbiomass was contributed from the northeastern India and northern Burma, and the Southeast Asia can explain 40 % of BCbiomass. The high BCfossil was mainly identified from the southeast of sampling site. A radiative transfer model estimated that the atmospheric directive radiative forcing of BC was +4.6 ± 2.4 W m−2 on average, including +2.5 ± 1.8 W m−2 from BCbiomass, and +2.1 ± 0.9 W m−2 from BCfossil, which correspond to and heating rates of 0.07 ± 0.05 and 0.06 ± 0.02 K day−1, respectively. Our study will be useful for improving our understanding in BC sources on the TP and their climatic effect.

Shan Zhou - One of the best experts on this subject based on the ideXlab platform.

  • Measurement Report ccn activity and its variation with organic oxidation level and volatility observed during aerosol life cycle intensive operational period alc iop
    Atmospheric Chemistry and Physics, 2021
    Co-Authors: Fan Mei, Jian Wang, Shan Zhou, Qi Zhang, Sonya Collier
    Abstract:

    Abstract. Cloud condensation nuclei (CCN) spectrum and the CCN activated fraction of size selected aerosols (SR-CCN) were measured at a rural site on Long Island during the Department of Energy (DOE) Aerosol Life Cycle Intensive Operational Period (ALC-IOP) from July 15 to August 15, 2011. During the last week of the ALC-IOP, the dependence of the activated fraction on aerosol volatility was characterized by sampling downstream of a thermodenuder operated at temperatures up to 100 ⁰C. Here we present aerosol properties, including aerosol total number concentration, CCN spectrum, and the CCN hygroscopicity for air masses of representative origins during the ALC-IOP. The hygroscopicity of organic species in the aerosol is derived from CCN hygroscopicity and chemical composition. The dependence of organic hygroscopicity on the organic oxidation level (e.g., atomic O:C ratio) agrees well with theoretical predictions and results from previous laboratory and field studies. The derived κorg and O:C ratio first increase as thermal denuder (TD) temperature increases from 20 ℃ (i.e., ambient temperature) to 50 or 75 ℃, then decreases as TD temperature further increases to 100 ℃. These trends are different from previous laboratory experiments and field observations, which Reported that organic O:C increased monotonically with increasing TD temperature, whereas κorg decreased with the TD temperature. The initial increases of O:C and κorg with TD temperature below 50 ℃ are likely due to the evaporation of more volatile organics with relatively lower O:C and hygroscopicity such as primary OA. Previous studies were either focused on laboratory-generated SOA or based on field observations at locations dominated by SOA.

S. Albertin - One of the best experts on this subject based on the ideXlab platform.

  • Measurement Report: Nitrogen isotopes (δ15N) and first quantification of oxygen isotope anomalies (Δ17O, δ18O) in atmospheric nitrogen dioxide
    'Copernicus GmbH', 2021
    Co-Authors: S. Albertin, J. Savarino, S. Bekki, A. Barbero, N. Caillon
    Abstract:

    The isotopic composition of nitrogen and oxygen in nitrogen dioxide (NO2) potentially carries a wealth of information about the dynamics of the nitrogen oxides (NOx = nitric oxide (NO) + NO2) chemistry in the atmosphere. While nitrogen isotopes of NO2 are subtle indicators of NOx emissions and chemistry, oxygen isotopes are believed to reflect only the O3 / NOx / VOC chemical regime in different atmospheric environments. In order to access this potential tracer of the tropospheric chemistry, we have developed an efficient active method to trap atmospheric NO2 on denuder tubes and measured, for the first time, its multi-isotopic composition (δ15N, δ18O, and Δ17O). The Δ17O values of NO2 trapped at our site in Grenoble, France, show a large diurnal cycle peaking in late morning at (39.2 ± 0.3) ‰ and decreasing at night until (20.5 ± 0.3) ‰. On top of this diurnal cycle, Δ17O also exhibits substantial daytime variability (from 29.7 ‰ to 39.2 ‰), certainly driven by changes in the O3 to peroxyl radicals (RO2) ratio. The nighttime decay of Δ17O(NO2) appears to be driven by NO2 slow removal, mostly from conversion into N2O5, and its formation from the reaction between O3 and freshly emitted NO. As expected from a nighttime Δ17O(NO2) expression, our Δ17O(NO2) measured towards the end of the night is quantitatively consistent with typical values of Δ17O(O3). Daytime N isotope fractionation is estimated using a general expression linking it to Δ17O(NO2). An expression is also derived for the nighttime N isotope fractionation. In contrast to Δ17O(NO2), δ15N(NO2) Measurements exhibit little diurnal variability (−11.8 ‰ to −4.9 ‰) with negligible isotope fractionations between NO and NO2, mainly due to high NO2 / NOx ratios, excepted during the morning rush hours. The main NOx emission sources are estimated using a Bayesian isotope mixing model, indicating the predominance of traffic emissions in this area. These preliminary results are very promising for using the combination of Δ17O and δ15N of NO2 as a probe of the NOx sources and fate and for interpreting nitrate isotopic composition records.

  • Measurement Report nitrogen isotopes δ 15 n and first quantification of oxygen isotope anomalies δ 17 o δ 18 o in atmospheric nitrogen dioxide
    Atmospheric Chemistry and Physics, 2020
    Co-Authors: S. Albertin, J. Savarino, S. Bekki, A. Barbero, N. Caillon
    Abstract:

    Abstract. The isotopic composition of nitrogen and oxygen in nitrogen dioxide (NO2) potentially carries a wealth of information about the dynamics of the nitrogen oxides (NOx = nitric oxide(NO) + NO2) chemistry in the atmosphere. While nitrogen isotopes of NO2 are subtle indicators of emissions, NOx chemistry and isotopic nitrogen exchange between NO and NO2, oxygen isotopes are believed to reflect only the O3/NOx/VOC chemical regime in different atmospheric environments. In order to access this potential tracer of the tropospheric chemistry, we have developed an efficient active method to trap atmospheric NO2 on denuder tubes and measured, for the first time, its multi-isotopic composition (δ15N, δ18O, and Δ17O). The δ15N values of NO2 trapped at our site in Grenoble, France, show little variability (−11.8 to −4.9 ‰) with negligible N isotope fractionations between NO and NO2 due to high NO2/NOx ratios. NOx emissions main sources are estimated using a stable isotope model indicating the predominance of traffic NOx emissions in this area. The Δ17O values, however, reveal an important diurnal cycle peaking in late morning at (39.2 ± 1.7) ‰ and decreasing at night until (20.5 ± 1.7) ‰. On top of this diurnal cycle, Δ17O also has substantial variability during the day (from 29.7 to 39.2 ‰), certainly driven by changes in the O3 to peroxyl radicals ratio. The night-time decay of Δ17O(NO2) appears to be driven by NO2 slow removal, mostly from conversion into N2O5, and its formation from the reaction between O3 and emitted NO. Our Δ17O(NO2) measured towards the end of the night is quantitatively consistent with typical values of Δ17O(O3). These preliminary results are very promising for using Δ17O of NO2 as a probe of the atmospheric oxidative activity and for interpreting NO3− isotopic composition records.

Yong Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Measurement Report quantifying source contribution of fossil fuels and biomass burning black carbon aerosol in the southeastern margin of the tibetan plateau
    Atmospheric Chemistry and Physics, 2021
    Co-Authors: Huikun Liu, Qiyuan Wang, Yong Zhang, Weikang Ran, Li Xing, Ting Zhang, Junji Cao
    Abstract:

    Abstract. Anthropogenic emissions of black carbon (BC) aerosol are transported from Southeast Asia to the southwestern Tibetan Plateau (TP) during the pre-monsoon; however, the quantities of BC from different anthropogenic sources and the transport mechanisms are still not well constrained because there have been no high-time-resolution BC source apportionments. Intensive Measurements were taken in a transport channel for pollutants from Southeast Asia to the southeastern margin of the TP during the pre-monsoon to investigate the influences of fossil fuels and biomass burning on BC. A receptor model that coupled multi-wavelength absorption with aerosol species concentrations was used to retrieve site-specific Angstrom exponents (AAEs) and mass absorption cross sections (MACs) for BC. An “aethalometer model” that used those values showed that biomass burning had a larger contribution to BC mass than fossil fuels (BC biomass=57  % versus BC fossil=43  %). The potential source contribution function indicated that BC biomass was transported to the site from northeastern India and northern Burma. The Weather Research and Forecasting model coupled with chemistry (WRF-Chem) indicated that 40 % of BC biomass originated from Southeast Asia, while the high BC fossil was transported from the southwest of the sampling site. A radiative transfer model indicated that the average atmospheric direct radiative effect (DRE) of BC was + 4.6  ±  2.4 W m −2 , with + 2.5  ±  1.8 W m −2 from BC biomass and + 2.1  ±  0.9 W m −2 from BC fossil . The DRE of BC biomass and BC fossil produced heating rates of 0.07  ±  0.05 and 0.06  ±  0.02 K d −1 , respectively. This study provides insights into sources of BC over a transport channel to the southeastern TP and the influence of the cross-border transportation of biomass-burning emissions from Southeast Asia during the pre-monsoon.

  • Measurement Report source and mixing state of black carbon aerosol in the north china plain implications for radiative effect
    Atmospheric Chemistry and Physics, 2020
    Co-Authors: Qiyuan Wang, Jiamao Zhou, Wenting Dai, Huikun Liu, Yong Zhang, Renjian Zhang, Jie Tian, Yang Chen, Weikang Ran
    Abstract:

    Abstract. Establishment of the sources and mixing state of black carbon (BC) aerosol is essential for assessing its impact on air quality and climatic effects. A winter campaign (December 2017–January 2018) was performed in the North China Plain (NCP) to evaluate the sources, coating composition, and radiative effects of BC under the background of emission reduction. Results showed that the sources of liquid fossil fuels (i.e., traffic emissions) and solid fuels (i.e., biomass and coal burning) contributed 69 % and 31 % to the total equivalent BC (eBC) mass, respectively. These values were arrived at by using a combination of multi-wavelength optical approach with the source-based aerosol absorption Angstrom exponent values. The air quality model indicated that local emissions were the dominant contributors to BC at the Measurement site. However, regional emissions from NCP were a critical factor for high BC pollution. A single-particle aerosol mass spectrometer identified six classes of elemental carbon (EC)-containing particles. They included EC coated by organic carbon and sulfate (52 % of total EC-containing particles); EC coated by Na and K (24 %); EC coated by K, sulfate, and nitrate (17 %); EC associated with biomass burning (6 %); pure-EC (1 %); and others (1 %). Different BC sources exhibited distinct impacts on the EC-containing particles. A radiative transfer model showed that the amount of detected eBC can produce an atmospheric direct radiative effect of +18.0  W m −2 and a heating rate of 0.5 K d −1 . This study shows that reductions of solid fuel combustion-related BC may be an effective way of mitigating regional warming in the NCP.

  • Measurement Report evaluation of sources and mixing state of black carbon aerosol under the background of emission reduction in the north china plain implications for radiative effect
    Atmospheric Chemistry and Physics, 2020
    Co-Authors: Qiyuan Wang, Jiamao Zhou, Yong Zhang, Renjian Zhang, Jie Tian, Yang Chen, Li Li, Jianhuai Ye, Yunfei Wu
    Abstract:

    Abstract. Accurate understanding of sources and mixing state of black carbon (BC) aerosol is essential for assessing its impacts on air quality and climatic effect. Here, a winter campaign (December 2017–January 2018) was conducted in the North China Plain (NCP) to evaluate the sources, coating composition, and radiative effect of BC under the background of emission reduction since 2013. Results show that liquid fossil fuel source (i.e., traffic emission) and solid fuel source (i.e., biomass and coal burning) contributed 69 % and 31 % to the total BC mass, respectively, using a multiwavelength optical approach combined with the source-based aerosol absorption Angstrom exponent values. The air quality model indicates that local emission was the dominant contributor to BC at the Measurement site on average, however, emissions in the NCP exerted a critical role for high BC episode. Six classes of BC-containing particles were identified, including (1) BC coated by organic carbon and sulphate (52 % of total BC-containing particles), (2) BC coated by Na and K (24 %), (3) BC coated by K, sulphate, and nitrate (17 %), (4) BC associated with biomass burning (6 %), (5) Pure-BC (1 %), and (6) others (1 %). Different BC sources had distinct impacts on those BC-containing particles. A radiative transfer model estimated that the amount of BC detected can produce an atmospheric forcing of +18.0 W m−2 and a heating rate of 0.5 K day−1. Results presented herein highlight that further reduction of solid fuel combustion-related BC may be a more effective way to mitigate regional warming in the NCP, although larger BC contribution was from liquid fossil fuel source.

  • Measurement Report quantifying source contribution and radiative forcing of fossil fuel and biomass burning black carbon aerosol in the southeastern margin of tibetan plateau
    Atmospheric Chemistry and Physics, 2020
    Co-Authors: Qiyuan Wang, Yong Zhang, Li Xing, Ting Zhang
    Abstract:

    Abstract. Black carbon (BC) aerosol plays a vital role in disturbing the balance of ecosystem and climate stability of Tibetan Plateau (TP). An intensive campaign was carried out from 14th March to 12th May 2018 in the southeastern margin of TP to investigate the sources of BC and their radiative effects. To do so, an improved aethalometer model was used to distinguish and apportion BC into fossil fuel combustion source and biomass burning source. To minimize the uncertainty associated with the aethalometer model , a receptor model coupling multi-wavelength absorption with chemical species was used to retrieve the site-dependent Angstrom exponent (AAE) and BC mass absorption cross-section (MAC). The results show that the AAEs and BC MACs at wavelength of 880 nm were 0.9 and 12.3 m2 g−1 for fossil fuel source and 1.7 and 10.4 m2 g−1 for biomass burning, respectively. Based on these parameters, the fossil fuel source-related BC (BCfossil) was estimated 43 % of the total BC and the rest 57 % was from biomass burning (BCbiomass) during the campaign. The results from a regional chemical dynamical model reveal that high BCbiomass was contributed from the northeastern India and northern Burma, and the Southeast Asia can explain 40 % of BCbiomass. The high BCfossil was mainly identified from the southeast of sampling site. A radiative transfer model estimated that the atmospheric directive radiative forcing of BC was +4.6 ± 2.4 W m−2 on average, including +2.5 ± 1.8 W m−2 from BCbiomass, and +2.1 ± 0.9 W m−2 from BCfossil, which correspond to and heating rates of 0.07 ± 0.05 and 0.06 ± 0.02 K day−1, respectively. Our study will be useful for improving our understanding in BC sources on the TP and their climatic effect.