Seasonal variability of carbon in humic-like matter of ambient size-segregated water soluble organic aerosols from urban background environment

Frka, Sanja; Grgić, Irena; Turšič, Janja; Gini, Maria I.; Eleftheriadis, Konstantinos

doi:10.1016/j.atmosenv.2017.11.013

Cited by 27 publications

(22 citation statements)

References 59 publications

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“…Earlier studies have investigated the size distributions of WSOCs (Deshmukh et al, 2016;Frka et al, 2018), and more recent studies have focused on the optical properties of sizesegregated WSOCs (Chen et al, 2019;Yue et al, 2019. Generally, the mass concentrations of WSOCs show bimodal dis-tributions with the dominant mass concentration in the accumulation mode (0.05-2 µm) (Yu et al, 2004(Yu et al, , 2016. Structural investigations on coal-burning-and biomass-burningaffected humic-like substances (HULIS; a significant fraction of WSOCs) in four size ranges found consistent organic species through all of the size ranges; however, the absorption bands of aromatic groups were more intense compared with carboxylic groups in the sub-3 µm fractions (Park et al, 2017;Voliotis et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Measurement report: Particle-size-dependent fluorescence properties of water-soluble organic compounds (WSOCs) and their atmospheric implications for the aging of WSOCs

et al. 2022

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Abstract. Water-soluble organic compounds (WSOCs) play important roles in atmospheric particle formation, migration, and transformation processes. Size-segregated atmospheric particles were collected in a rural area of Beijing. Three-dimensional fluorescence spectroscopy was used to investigate the optical properties of WSOCs as a means of inferring information about their atmospheric sources. Sophisticated analysis on fluorescence data was performed to characteristically estimate the connections among particles of different sizes. WSOC concentrations and the average fluorescence intensity (AFI) showed a monomodal distribution in winter and a bimodal distribution in summer, with the dominant mode in the 0.26–0.44 µm size range in both seasons. The excitation–emission matrix (EEM) spectra of WSOCs varied with particle size, likely due to changing sources and/or the chemical transformation of organics. Size distributions of the fluorescence regional integration (regions III and V) and humification index (HIX) indicate that the humification degree or aromaticity of WSOCs was the highest in the particle size range of 0.26–0.44 µm. The Stokes shift (SS) and the harmonic mean of the excitation and emission wavelengths (WH) reflected that π-conjugated systems were high in the same particle size range. The parallel factor analysis (PARAFAC) results showed that humic-like substances were abundant in fine particles (< 1 µm) and peaked at 0.26–0.44 µm. All evidence supported the fact that the humification degree of WSOCs increased with particle size in the submicron mode (< 0.44 µm) and then decreased gradually with particle size, which implied that the condensation of organics occurred in submicron particles, resulting in the highest degree of humification in the particle size range of 0.26–0.44 µm rather than in the < 0.26 µm range. Synthetically analyzing three-dimensional fluorescence data could efficiently reveal the secondary transformation processes of WSOCs.

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Section: Introductionmentioning

confidence: 99%

Measurement report: Particle-size-dependent fluorescence properties of water-soluble organic compounds (WSOCs) and their atmospheric implications for the aging of WSOCs

et al. 2022

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“…Organic compounds account for a considerable fraction (20 %-60 %) of atmospheric aerosols (Huang et al, 2014;Zhang et al, 2020), and water-soluble organic carbon (WSOC) generally composes 30 %-70 % of organic carbon (OC) (Zhang et al, 2018;Yang et al, 2019;Chen et al, 2020). WSOC in aerosols is active in light adsorption (Yan et al, 2015;Geng et al, 2020) and thus may make a significant impact on radiative forcing and global climate change (Andreae and Gelencser, 2006). Meanwhile, the photoexcitation of water-soluble brown carbon (BrC) can generate oxidants in aerosols and cloud/fog droplets (Manfrin et al, 2019;Kaur et al, 2019), which can promote atmospheric chemical reactions and aging processes of organic aerosols.…”

Section: Introductionmentioning

confidence: 99%

Characteristics, primary sources and secondary formation of water-soluble organic aerosols in downtown Beijing

Chen

Qin

et al. 2021

Atmos. Chem. Phys.

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Abstract. Water-soluble organic carbon (WSOC) accounts for a large proportion of aerosols and plays a critical role in various atmospheric chemical processes. In order to investigate the primary sources and secondary production of WSOC in downtown Beijing, day and night fine particulate matter (PM2.5) samples in January (winter), April (spring), July (summer) and October (autumn) 2017 were collected and analyzed for WSOC and organic tracers in this study. WSOC was dominated by its moderately hydrophilic fraction and showed the highest concentration in January and comparable levels in April, July and October 2017. Some typical organic tracers were chosen to evaluate the emission strength and secondary formation of WSOC. Seasonal variation of the organic tracers suggested significantly enhanced formation of anthropogenic secondary organic aerosols (SOAs) during the sampling period in winter and obviously elevated biogenic SOA formation during the sampling period in summer. These organic tracers were applied into a positive matrix factorization (PMF) model to calculate the source contributions of WSOC as well as its moderately and strongly hydrophilic portions. The secondary sources contributed more than 50 % to WSOC, with higher contributions during the sampling periods in summer (75.1 %) and winter (67.4 %), and the largest contributor was aromatic SOC. In addition, source apportionment results under different pollution levels suggested that controlling biomass burning and aromatic precursors would be effective to reduce WSOC during the haze episodes in cold seasons. The impact factors for the formation of different SOA tracers and total secondary organic carbon (SOC) as well as moderately and strongly hydrophilic SOC were also investigated. The acid-catalyzed heterogeneous or aqueous-phase oxidation appeared to dominate in the SOC formation during the sampling period in winter, while the photochemical oxidation played a more critical role during the sampling period in summer. Moreover, photooxidation played a more critical role in the formation of moderately hydrophilic SOC, while the heterogeneous or aqueous-phase reactions had more vital effects on the formation of strongly hydrophilic SOC.

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“…Besides, the photo-induced oligomerization of some phenolic compounds could also form HULISws (Vione et al, 2019). Field observations reported an obviously higher contribution of the ultrafine aerosol mode to the hydrophobic WSOC in summer, which suggested that the formation of the hydrophobic SO was tightly associated with the gaseous phase nucleation (Frka et al, 2018). In comparison, the ratio of https://doi.org/10.5194/acp-2020-726 Preprint.…”

Section: Exploratory Formation Mechanisms Of Hydrophobic and Hydrophimentioning

confidence: 99%

Characteristics, primary sources and secondary formation of water soluble organic aerosols in downtown Beijing

Qian¹,

Chen²,

Qin³

et al. 2020

Preprint

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Abstract. Water soluble organic compounds (WSOC) account for a large proportion of aerosols and play a critical role in various atmospheric chemical processes. In order to investigate the primary sources and secondary production of WSOC in downtown Beijing, the day and night PM2.5 samples in January (winter), April (spring), July (summer) and October (autumn) of 2017 were collected and analyzed for WSOC and organic tracers in this study. WSOC showed the highest concentration in winter and comparable levels in the other seasons, and dominated by its hydrophobic fraction (HULIS-C). Some typical organic tracers were chosen to evaluate the emission strength and secondary formation for the major sources of WSOC. According to the diurnal patterns and correlation coefficients with the key influencing factors, most SOA tracers were closely related to gaseous photooxidation in summer, but mainly generated via aqueous-phase processing in other seasons. These organic tracers were applied into the positive matrix factorization (PMF) model to calculate the source contributions of WSOC as well as its hydrophobic and hydrophilic portions. The secondary sources contributed over 50 % to WSOC, with higher contributions in summer (75.7 %) and winter (67.7 %), and the largest contributor was aromatic SOC. Besides, the source apportionment results under different pollution levels suggested that controlling biomass burning and the aromatic precursors would be effective to reduce WSOC during the haze episodes in cold seasons. The possible formation mechanisms of the total secondary organic carbon (SOC) as well as hydrophobic and hydrophilic SOC were also explored in this study. The aqueous-phase process appeared to dominate in the SOC formation in winter and spring, while gas-phase photooxidation played a dominant role in summer. Besides, the gaseous photooxidation played a major role in the generation of hydrophobic SOC, whereas aqueous-phase reactions posed vital effects on the formation of hydrophilic SOC.

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Seasonal variability of carbon in humic-like matter of ambient size-segregated water soluble organic aerosols from urban background environment

Cited by 27 publications

References 59 publications

Measurement report: Particle-size-dependent fluorescence properties of water-soluble organic compounds (WSOCs) and their atmospheric implications for the aging of WSOCs

Measurement report: Particle-size-dependent fluorescence properties of water-soluble organic compounds (WSOCs) and their atmospheric implications for the aging of WSOCs

Characteristics, primary sources and secondary formation of water-soluble organic aerosols in downtown Beijing

Characteristics, primary sources and secondary formation of water soluble organic aerosols in downtown Beijing

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