Photochemical Aging of Soot in the Aqueous Phase: Release of Dissolved Black Carbon and the Formation of 1O2

2019 ◽  
Vol 53 (21) ◽  
pp. 12311-12319 ◽  
Author(s):  
Meng Li ◽  
Fengxia Bao ◽  
Yue Zhang ◽  
Hua Sheng ◽  
Chuncheng Chen ◽  
...  
Keyword(s):  
Black Carbon ◽  
Aqueous Phase ◽  
Photochemical Aging

scholarly journals Supplementary material to "Influence of photochemical aging on light absorption of atmospheric black carbon and aerosol single scattering albedo"

2018 ◽  
Author(s):  
Xuezhe Xu ◽  
Weixiong Zhao ◽  
Xiaodong Qian ◽  
Shuo Wang ◽  
Bo Fang ◽  
...  
Keyword(s):  
Black Carbon ◽  
Light Absorption ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Supplementary Material ◽  
Photochemical Aging

scholarly journals Further improvement of wet process treatments in GEOS-Chem v12.6.0: impact on global distributions of aerosols and aerosol precursors

2020 ◽  
Vol 13 (6) ◽  
pp. 2879-2903 ◽  
Author(s):  
Gan Luo ◽  
Fangqun Yu ◽  
Jonathan M. Moch
Keyword(s):  
Nitric Acid ◽  
Black Carbon ◽  
Aqueous Phase ◽  
Dry Deposition ◽  
Acid Sulfate ◽  
Surface Mass ◽  
Wet Process ◽  
Wet Surface ◽  
Phase Chemistry ◽  
Mass Concentrations

Abstract. Wet processes, including aqueous-phase chemistry, wet scavenging, and wet surface uptake during dry deposition, are important for global modeling of aerosols and aerosol precursors. In this study, we improve the treatments of these wet processes in the Goddard Earth Observing System with chemistry (GEOS-Chem) v12.6.0, including pH calculations for cloud, rain, and wet surfaces, the fraction of cloud available for aqueous-phase chemistry, rainout efficiencies for various types of clouds, empirical washout by rain and snow, and wet surface uptake during dry deposition. We compare simulated surface mass concentrations of aerosols and aerosol precursors with surface monitoring networks over the United States, European, Asian, and Arctic regions, and show that model results with updated wet processes agree better with measurements for most species. With the implementation of these updates, normalized mean biases (NMBs) of surface nitric acid, nitrate, and ammonium are reduced from 78 %, 126 %, and 45 % to 0.9 %, 15 %, and 4.1 % over the US sites, from 107 %, 127 %, and 90 % to −0.7 %, 4.2 %, and 16 % over European sites, and from 121 %, 269 %, and 167 % to −21 %, 37 %, and 86 % over Asian remote region sites. Comparison with surface measured SO2, sulfate, and black carbon at four Arctic sites indicated that those species simulated with the updated wet processes match well with observations except for a large underestimate of black carbon at one of the sites. We also compare our model simulation with aircraft measurement of nitric acid and aerosols during the Atmospheric Tomography Mission (ATom)-1 and ATom-2 periods and found a significant improvement of modeling skill of nitric acid, sulfate, and ammonium in the Northern Hemisphere during wintertime. The NMBs of these species are reduced from 163 %, 78 %, and 217 % to −13 %, −1 %, and 10 %, respectively. The investigation of impacts of updated wet process treatments on surface mass concentrations indicated that the updated wet processes have strong impacts on the global means of nitric acid, sulfate, nitrate, and ammonium and relative small impacts on the global means of sulfur dioxide, dust, sea salt, black carbon, and organic carbon.

scholarly journals Further improvement of wet process treatments in GEOS-Chem v12.6.0: Impact on global distributions of aerosol precursors and aerosols

2020 ◽  
Author(s):  
Gan Luo ◽  
Fangqun Yu ◽  
Jonathan M. Moch
Keyword(s):  
Nitric Acid ◽  
Black Carbon ◽  
Aqueous Phase ◽  
Dry Deposition ◽  
The United States ◽  
Surface Mass ◽  
Wet Process ◽  
Wet Surface ◽  
Phase Chemistry ◽  
Mass Concentrations

Abstract. Wet processes, including aqueous phase chemistry, wet scavenging, and wet surface uptakes during dry deposition, are important for global modeling of aerosol precursors and aerosols. In this study, we improved the treatments of these wet processes in the GEOS-Chem v12.6.0, including pH calculation for cloud, rain, and wet surface, fraction of cloud available for aqueous phase chemistry, rainout efficiencies for various types of cloud, empirical washout by rain and snow, and wet surface uptakes during dry deposition. We compared simulated surface mass concentrations of aerosol precursors and aerosols with surface monitoring networks over the United States, Europe, Asia, and Arctic regions, and showed that the model results with the updated wet processes agree better with measurements for most species. With the implementation of these updates, normalized mean biases (NMB) of surface nitric acid, nitrate, and ammonium are reduced from 78 %, 126 %, and 45 % to 13 %, 24 %, and 6.2 % over US sites, from 56 %, 105 %, and 91 % to −20 %, −5.1 %, and 22 % over Europe sites, and from 121 %, 269 %, and 167 % to −18 %, 40 %, and 86 % over Asia sites. Comparison with surface measured SO2, sulfate and black carbon at four Arctic sites indicated that these species simulated with the updated wet processes match well with observations except large underestimation of black carbon at one of the sites. Furthermore, we compared model simulation with aircraft measurement of nitric acid and aerosols during ATom-1 and ATom-2 periods and found seasonal variation and vertical profile of these species have been successfully improved by considering the updated wet processes. The investigation of impacts of updated wet process treatments on surface mass concentrations indicated that the updated wet processes have strong impacts on the global means of nitric acid, sulfate, nitrate, and ammonium and relative small impacts on the global means of sulfur dioxide, dust, sea salt, black carbon, and organic carbon.

scholarly journals Uptake of nitric acid, ammonia, and organics in orographic clouds: mass spectrometric analyses of droplet residual and interstitial aerosol particles

2017 ◽  
Vol 17 (2) ◽  
pp. 1571-1593 ◽  
Author(s):  
Johannes Schneider ◽  
Stephan Mertes ◽  
Dominik van Pinxteren ◽  
Hartmut Herrmann ◽  
Stephan Borrmann
Keyword(s):  
Nitric Acid ◽  
Black Carbon ◽  
Aqueous Phase ◽  
Aerosol Particles ◽  
Organic Nitrates ◽  
Temperature Dependent ◽  
Cloud Droplets ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Mass Fractions

Abstract. Concurrent in situ analyses of interstitial aerosol and cloud droplet residues have been conducted at the Schmücke mountain site during the Hill Cap Cloud Thuringia campaign in central Germany in September and October 2010. Cloud droplets were sampled from warm clouds (temperatures between −3 and +16 °C) by a counterflow virtual impactor and the submicron-sized residues were analyzed by a compact time-of-flight aerosol mass spectrometer (C-ToF-AMS), while the interstitial aerosol composition was measured by an high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). During cloud-free periods, the submicron out-of-cloud aerosol was analyzed using both instruments, allowing for intercomparison between the two instruments. Further instrumentation included black carbon measurements and optical particle counters for the aerosol particles as well as optical sizing instrumentation for the cloud droplets. The results show that, under cloud conditions, on average 85 % of the submicron aerosol mass partitioned into the cloud liquid phase. Scavenging efficiencies of nitrate, ammonium, sulfate, and organics ranged between 60 and 100 %, with nitrate having, in general, the highest values. For black carbon, the scavenging efficiency was markedly lower (about 24 %). The nitrate and ammonium mass fractions were found to be markedly enhanced in cloud residues, indicating uptake of gaseous nitric acid and ammonia into the aqueous phase. This effect was found to be temperature dependent: at lower temperatures, the nitrate and ammonium mass fractions in the residues were higher. Also, the oxidation state of the organic matter in cloud residues was found to be temperature dependent: the O : C ratio was lower at higher temperatures. A possible explanation for this observation is a more effective uptake and/or higher concentrations of low-oxidized water-soluble volatile organic compounds, possibly of biogenic origin, at higher temperatures. Organic nitrates were observed in cloud residuals as well as in the out-of-cloud aerosol, but no indication of a preferred partitioning of organic nitrates into the aqueous phase or into the gas phase was detected. Assuming the uptake of nitric acid and ammonia in cloud droplets will be reversible, it will lead to a redistribution of nitrate and ammonium among the aerosol particles, leading to more uniform, internally mixed particles after several cloud passages.

Photochemical Aging of Atmospheric Particulate Matter in the Aqueous Phase

2021 ◽  
Author(s):  
Frank Leresche ◽  
Joseph R. Salazar ◽  
David J. Pfotenhauer ◽  
Michael P. Hannigan ◽  
Brian J. Majestic ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Aqueous Phase ◽  
Atmospheric Particulate Matter ◽  
Atmospheric Particulate ◽  
Photochemical Aging

scholarly journals Uptake of nitric acid, ammonia, and organics in orographic clouds: Mass spectrometric analyses of droplet residual and interstitial aerosol particles

2016 ◽  
Author(s):  
Johannes Schneider ◽  
Stephan Mertes ◽  
Dominik van Pinxteren ◽  
Hartmut Herrmann ◽  
Stephan Borrmann
Keyword(s):  
Nitric Acid ◽  
Black Carbon ◽  
Aqueous Phase ◽  
Aerosol Particles ◽  
Water Soluble ◽  
Organic Nitrates ◽  
Temperature Dependent ◽  
Cloud Droplets ◽  
Mass Fractions ◽  
Orographic Clouds

Abstract. Concurrent in-situ analyses of interstitial aerosol and cloud droplet residues have been conducted at the Schmücke mountain site during the Hill Cap Cloud Thuringia campaign in central Germany in September and October 2010. Cloud droplets were sampled from warm clouds (temperatures between −3 and +16 °C) by a counterflow virtual impactor and the submicron-sized residues were analyzed by a C-ToF-AMS, while the interstitial aerosol composition was measured by an HR-ToF-AMS. During cloud-free periods the submicron out-of-cloud aerosol was analyzed using both instruments, allowing for intercomparison between the two instruments. Further instrumentation included black carbon measurements and optical particle counters for the aerosol particles as well as optical sizing instrumentation for the cloud droplets. The results show that under cloud conditions on average 85 % of the submicron aerosol mass partitioned into the cloud liquid phase. Scavenging efficiencies of nitrate, ammonium, sulfate, and organics ranged between 60 and 100 %, with nitrate having in general the highest values. For black carbon, the scavenging efficiency was markedly lower (about 24 %). The nitrate and ammonium mass fractions were found to be markedly enhanced in cloud residues, indicating uptake of gaseous nitric acid and ammonia into the aqueous phase. This effect was found to be temperature dependent: At lower temperatures the nitrate and ammonium mass fractions in the residues were higher. Also, the oxidation state of the organic matter in cloud residues was found to be temperature dependent: The O:C ratio was lower at higher temperatures. A possible explanation for this observation is a more effective uptake and/or higher concentrations of low-oxidized water soluble volatile organic compounds, possibly of biogenic origin, at higher temperatures. Organic nitrates were observed in cloud residuals as well as in the out-of-cloud aerosol, but no indication of a preferred partitioning of organic nitrates into the aqueous phase or into the gas phase was detected. Assuming the uptake of nitric acid and ammonia in cloud droplets to be reversible, it will lead to a redistribution of nitrate and ammonium among the aerosol particles, leading to more uniform, internally mixed particles after several cloud passages.

scholarly journals Influence of photochemical aging on light absorption of atmospheric black carbon and aerosol single scattering albedo

2018 ◽  
Author(s):  
Xuezhe Xu ◽  
Weixiong Zhao ◽  
Xiaodong Qian ◽  
Shuo Wang ◽  
Bo Fang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Black Carbon ◽  
Light Absorption ◽  
Radiative Forcing ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Rural Site ◽  
Absorption Enhancement ◽  
Diurnal Variability ◽  
Photochemical Aging

Abstract. Coating enhancement of black carbon (BC) light absorption (Eabs) is a large uncertainty in modelling direct radiative forcing (DRF) by BC. Reported Eabs values after atmospheric aging vary widely and the mechanisms responsible for enhancing BC absorption remain elusive. Here, we report on the direct field measurement of size-resolved mixing state, Eabs and aerosol single scattering albedo (SSA) at λ = 532 nm at a rural site in East China from June to July 2016. Strong diurnal variability of Eabs, SSA, and Ox (Ox = NO2 + O3, a proxy for atmospheric photochemical aging) was observed. A three-stage absorption enhancement process for collapsed semispherical to fully compact spherical morphology BC with photochemical aging was suggested. For Ox below 35 ppbv, Eabs increased slowly with Ox mixing ratio and ranged from 2.0 to 2.2 (with a growth rate of ~ 0.03 ppbv−1). Eabs was stable (Eabs = 2.26 ± 0.06) between 35 to 50 ppbv Ox. Thirdly, for Ox levels above 50 ppbv, Eabs grew rapidly from 2.3 to 2.8 (at a growth rate of ~ 0.18 ppbv−1). A method that combined Eabs and SSA was developed to retrieve the fraction contribution of BC absorption (fBC), lensing driven enhancement (fLens), as well as the fractional contribution of coating absorption (fraction absorption contribution (fShell), the coated shell diameter (DShell) and the imaginary part of the complex refractive index (CRI) of the shell (kShell)). Parameterization of Eabs and SSA captures much of the influence of BC coating and the particle absorption, and provides a plausible new method to better constrain the contribution of BC to the DRF. In our measurements at this site, the absorption amplification depended mainly on the coating thickness and the absorption of coating materials. The lensing driven enhancement was reduced by light absorption of the shell. Our observations highlight the crucial role of photochemical processes in modifying the absorption of BC-containing particles. One implication of these findings is that the contribution of light-absorbing organic compounds (Brown carbon, BrC) at longer aging time should be included in climate models.

Photochemical Aging of Guaiacol by Fe(III)–Oxalate Complexes in Atmospheric Aqueous Phase

2018 ◽  
Vol 53 (1) ◽  
pp. 127-136 ◽  
Author(s):  
Hongwei Pang ◽  
Qi Zhang ◽  
Hongli Wang ◽  
Dongmei Cai ◽  
Yingge Ma ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Oxalate Complexes ◽  
Photochemical Aging

scholarly journals The influence of photochemical aging on light absorption of atmospheric black carbon and aerosol single-scattering albedo

2018 ◽  
Vol 18 (23) ◽  
pp. 16829-16844 ◽  
Author(s):  
Xuezhe Xu ◽  
Weixiong Zhao ◽  
Xiaodong Qian ◽  
Shuo Wang ◽  
Bo Fang ◽  
...  
Keyword(s):  
Black Carbon ◽  
Light Absorption ◽  
Radiative Forcing ◽  
Climate Models ◽  
Complex Refractive Index ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Rural Site ◽  
Diurnal Variability ◽  
Photochemical Aging

Abstract. Coating enhancement of black carbon (BC) light absorption (Eabs) is a large uncertainty in modelling direct radiative forcing (DRF) by BC. Reported Eabs values after atmospheric aging vary widely and the mechanisms responsible for enhancing BC absorption remain elusive. Here, we report on the direct field measurement of size-resolved mixing state, Eabs, and aerosol single-scattering albedo (SSA) at λ = 532 nm at a rural site in east China from June to July 2016. Strong diurnal variability of Eabs, SSA, and Ox (Ox = NO2 + O3, a proxy for atmospheric photochemical aging) was observed. A method that combined Eabs and SSA was developed to retrieve the fraction contribution of BC absorption (fBC), lensing-driven enhancement (fLens), as well as the fractional contribution of coating absorption (fraction absorption contribution (fShell), the coated shell diameter (DShell) and the imaginary part of the complex refractive index (CRI) of the shell (kShell)). Parameterization of Eabs and SSA captures much of the influence of BC coating and the particle absorption. In our measurements at this site, the results showed that the absorption amplification depended on the coating thickness and the absorption of coating materials, and photochemistry plays a role in modifying the absorption of BC-containing particles. The lensing-driven enhancement was reduced by light absorption of the shell. One implication of these findings is that the contribution of light-absorbing organic compounds (brown carbon, BrC) at a longer aging time should be included in climate models.

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