Characterizing the ratio of nitrate to sulfate in ambient fine particles of urban Beijing during 2018–2019

Li, Shangze; Zhang, Fang; Jin, Xu; Shrivastava, Manish; Wu, Hao; Xie, Conghui; Chen, Lu; Liu, Jieyao; Wu, Tong; Jiang, Sihui; Cribb, Maureen; Li, Zhanqing

doi:10.1016/j.atmosenv.2020.117662

Cited by 25 publications

(16 citation statements)

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“…In particular, the average SNR for the BC‐containing particles is ∼2 times those for the BC‐free particles in summer and autumn. Such a seasonal variation of SNR is similar to the concentration ratio observed for fine particles in Beijing, with the mean SNR in warmer seasons more than two times that in cold seasons (Li et al., 2020). However, the difference of SNRs between the BC‐containing and BC‐free particles cannot be ruled out based on previous bulk analysis.…”

Section: Resultssupporting

confidence: 79%

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Black Carbon Involved Photochemistry Enhances the Formation of Sulfate in the Ambient Atmosphere: Evidence From In Situ Individual Particle Investigation

Zhang

Peng

et al. 2021

JGR Atmospheres

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Mixing state of black carbon (BC) with secondary species has been highlighted as a major uncertainty in assessing its radiative forcing. While recent laboratory simulation has demonstrated that BC could serve as a catalyst to enhance the formation of sulfate, its role in the formation and evolution of secondary aerosols in the real atmosphere remains poorly understood. In the present study, the mixing of BC with sulfate/nitrate in the atmosphere of Guangzhou (China) was directly investigated with a single particle aerosol mass spectrometer (SPAMS). The peak area ratios of sulfate to nitrate (SNRs) for the BC‐containing particles are constantly higher than those of the BC‐free particles (defined as particles with negligible BC signals). Furthermore, the seasonal SNR peak is observed in summer and autumn, and the diurnal peak is found in the afternoon, consistent with the trends of radiation‐related parameters (i.e., solar radiation and temperature), pointing to the BC‐induced photochemical production of sulfate. Such hypothesis is further supported by the multilinear regression and random forest analysis, showing that the variation of SNRs associated with the BC‐containing particles could be well explained (R2 = ∼0.7–0.8) by the radiation‐related parameters (>30% of the variance) and the relative BC content (∼20%) in individual particles, but with limited influence of precursors (SO2/NOx: <5%). Differently, the radiation‐related factors only explain <10% of the SNR variation for the BC‐free particles. These results provide ambient observational evidence pointing to a unique role of BC on the photochemical formation and evolution of sulfate, which merits further quantitative evaluations.

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Section: Resultssupporting

confidence: 79%

“…Our analysis may provide an additional explanation associated with photochemistry on the BC‐containing particles. The mechanism might also be particularly important during haze episodes when heterogeneous chemistry is thought to play a considerable role in sulfate production (Li et al., 2020; Zheng et al., 2015).…”

Section: Discussionmentioning

confidence: 99%

Black Carbon Involved Photochemistry Enhances the Formation of Sulfate in the Ambient Atmosphere: Evidence From In Situ Individual Particle Investigation

Zhang

Peng

et al. 2021

JGR Atmospheres

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“…Currently, there is still a lack of understanding of the water uptake capacity for OA from multiple anthropogenic sources in polluted urban atmosphere. The OA dominates ambient fine composition in Beijing, with a mass fraction of 40-51% (Guo et al, 2014;Sun et al, 2015;Wang et al, 2016), and the composition of aerosol is complex due to both primary sources and secondary gas-to-particle conversion (Guo et al, 2014;Li et al, 2020;Ren et al, 2018;Zhang et al, 2015Zhang et al, , 2019Zhang et al, , 2020. With the aim of obtaining insights of the links between hygroscopicity of OA and its growth mechanisms, in this study, we retrieve and characterize the hygroscopic parameter of OA (κ org ) by using field campaign observed data of hygroscopic growth factor and chemical composition in urban Beijing.…”

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confidence: 99%

Hygroscopicity of Organic Aerosols Linked to Formation Mechanisms

Liu

Zhang

et al. 2021

Geophysical Research Letters

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Organic aerosols (OAs) account for a large fraction of tropospheric fine particulate matter, but the hygroscopicity of OA is poorly understood. Here, we show remarkably‐enhanced water uptake capacity of OA due to formation of highly‐oxidized oxygenated OA on new particle formation (NPF) events in Beijing. While non‐nucleation processes also produce oxidized OA, their hygroscopicity exhibits little enhancement. As a result, a correlation between the hygroscopicity and oxidation state is absent for OA on non‐NPF days. Further analysis reveals that the highly‐oxidized oxygenated OA is 2.5 and 5‐fold as hygroscopic as the oxidized primary OA and less‐oxidized oxygenated OA, respectively. Our results suggest that nucleation‐initiated photooxidation of volatile organic compounds to produce water‐soluble organic acids may dominate on NPF days, and the aqueous oligomerization to yield less water‐soluble products might occur on non‐NPF days.

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“…Since no AMS data are available for the CN campaign, we assumed the mass fraction of different chemical components according to contemporaneous measurements in Beijing, China (Zhou et al, 2019;Li et al, 2020), as shown in Table B3. Under the assumption of ρ a = 1600 kg m −1 (Zamora et al, 2019), Mass c,k in the CN campaign can be obtained from Eq.…”

Section: Aerosol Data For Inputmentioning

confidence: 99%

Evaluation of a quasi-steady-state approximation of the cloud droplet growth equation (QDGE) scheme for aerosol activation in global models using multiple aircraft data over both continental and marine environments

et al. 2022

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Abstract. This research introduces a numerically efficient aerosol activation scheme and evaluates it by using stratus and stratocumulus cloud data sampled during multiple aircraft campaigns in Canada, Chile, Brazil, and China. The scheme employs a quasi-steady-state approximation of the cloud droplet growth equation (QDGE) to efficiently simulate aerosol activation, the vertical profile of supersaturation, and the activated cloud droplet number concentration (CDNC) near the cloud base. The calculated maximum supersaturation values using the QDGE scheme were compared with multiple parcel model simulations under various aerosol and environmental conditions. The differences are all below 0.18 %, indicating good performance and accuracy of the QDGE scheme. We evaluated the QDGE scheme by specifying observed environmental thermodynamic variables and aerosol information from 31 cloud cases as input and comparing the simulated CDNC with cloud observations. The average of mean relative error (MRE‾) of the simulated CDNC for cloud cases in each campaign ranges from 17.30 % in Brazil to 25.90 % in China, indicating that the QDGE scheme successfully reproduces observed variations in CDNC over a wide range of different meteorological conditions and aerosol regimes. Additionally, we carried out an error analysis by calculating the maximum information coefficient (MIC) between the MRE and input variables for the individual campaigns and all cloud cases. MIC values were then sorted by aerosol properties, pollution level, environmental humidity, and dynamic condition according to their relative importance to MRE. Based on the error analysis, we found that the magnitude of MRE is more relevant to the specification of input aerosol pollution level in marine regions and aerosol hygroscopicity in continental regions than to other variables in the simulation.

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Characterizing the ratio of nitrate to sulfate in ambient fine particles of urban Beijing during 2018–2019

Cited by 25 publications

References 50 publications

Black Carbon Involved Photochemistry Enhances the Formation of Sulfate in the Ambient Atmosphere: Evidence From In Situ Individual Particle Investigation

Black Carbon Involved Photochemistry Enhances the Formation of Sulfate in the Ambient Atmosphere: Evidence From In Situ Individual Particle Investigation

Hygroscopicity of Organic Aerosols Linked to Formation Mechanisms

Evaluation of a quasi-steady-state approximation of the cloud droplet growth equation (QDGE) scheme for aerosol activation in global models using multiple aircraft data over both continental and marine environments

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