scholarly journals Supplementary material to "Characteristics, primary sources and secondary formation of water soluble organic aerosols in downtown Beijing"

2020 ◽  
Author(s):  
Qing Yu ◽  
Jing Chen ◽  
Weihua Qin ◽  
Siming Cheng ◽  
Yuepeng Zhang ◽  
...  
Keyword(s):  
Organic Aerosols ◽  
Water Soluble ◽  
Primary Sources ◽  
Secondary Formation ◽  
Supplementary Material

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

2021 ◽  
Vol 21 (3) ◽  
pp. 1775-1796
Author(s):  
Qing Yu ◽  
Jing Chen ◽  
Weihua Qin ◽  
Siming Cheng ◽  
Yuepeng Zhang ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Aqueous Phase ◽  
Critical Role ◽  
Organic Aerosols ◽  
Sampling Period ◽  
Water Soluble ◽  
Photochemical Oxidation ◽  
Primary Sources ◽  
Secondary Formation ◽  
The Impact

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.

Primary Sources and Secondary Formation of Organic Aerosols in Beijing, China

2012 ◽  
Vol 46 (18) ◽  
pp. 9846-9853 ◽  
Author(s):  
Song Guo ◽  
Min Hu ◽  
Qingfeng Guo ◽  
Xin Zhang ◽  
Mei Zheng ◽  
...  
Keyword(s):  
Organic Aerosols ◽  
Primary Sources ◽  
Secondary Formation ◽  
Beijing China

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

2020 ◽  
Author(s):  
Qing Yu ◽  
Jing Chen ◽  
Weihua Qin ◽  
Siming Cheng ◽  
Yuepeng Zhang ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Dominant Role ◽  
Critical Role ◽  
Correlation Coefficients ◽  
Water Soluble ◽  
Primary Sources ◽  
Formation Mechanisms ◽  
Secondary Sources ◽  
Pmf Model ◽  
Secondary Formation

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.

scholarly journals Large contribution of fossil-fuel derived secondary organic carbon to water-soluble organic aerosols in winter haze of China

2017 ◽  
Author(s):  
Yan-Lin Zhang ◽  
Imad El-Haddad ◽  
Ru-Jin Huang ◽  
Kin-Fai Ho ◽  
Jun-Ji Cao ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Source Apportionment ◽  
Atmospheric Chemistry ◽  
Coal Combustion ◽  
Large Fraction ◽  
Organic Aerosols ◽  
Water Soluble ◽  
Primary Sources ◽  
Large Contribution ◽  
Secondary Organic Carbon

Abstract. Water-soluble organic carbon (WSOC) is a large fraction of organic aerosols (OA) globally and has significant impacts on climate and human health. The sources of WSOC remain very uncertain in polluted regions. Here we present a quantitative source apportionment of WSOC isolated from aerosols in China using radiocarbon (14C) and offline high-resolution time-of-flight aerosol mass spectrometer measurements. Fossil emissions on average accounted for 32–47 % of WSOC. Secondary organic carbon (SOC) dominated both the non-fossil and fossil derived WSOC, highlighting the importance of secondary formation to WSOC in severe winter haze episodes. Contributions from fossil emissions to SOC were 61 ± 4 % and 50 ± 9 % in Shanghai and Beijing, respectively, significantly larger than those in Guangzhou (36 ± 9 %) and Xi'an (26 ± 9 %). The most important primary sources were biomass burning emissions, contributing 17–26 % of WSOC. The remaining primary sources such as coal combustion, cooking and traffic were generally very small but not negligible contributors, as coal combustion contribution could exceed 10 %. Taken together with earlier 14C source apportionment studies in urban, rural, semi-urban, and background regions in Asia, Europe and USA, we demonstrated a dominant contribution of non-fossil emissions (i.e., 75 ± 11 %) to WSOC aerosols in the North Hemisphere; however, the fossil fraction is substantially larger in aerosols from East Asia and the East Asian pollution outflow especially during winter due to increasing coal combustion. Inclusion of our findings can improve a modelling of effects of WSOC aerosols on climate, atmospheric chemistry and public health.

scholarly journals Large contribution of fossil fuel derived secondary organic carbon to water soluble organic aerosols in winter haze in China

2018 ◽  
Vol 18 (6) ◽  
pp. 4005-4017 ◽  
Author(s):  
Yan-Lin Zhang ◽  
Imad El-Haddad ◽  
Ru-Jin Huang ◽  
Kin-Fai Ho ◽  
Jun-Ji Cao ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Source Apportionment ◽  
Atmospheric Chemistry ◽  
Coal Combustion ◽  
Large Fraction ◽  
Organic Aerosols ◽  
Water Soluble ◽  
Primary Sources ◽  
Large Contribution ◽  
Secondary Organic Carbon

Abstract. Water-soluble organic carbon (WSOC) is a large fraction of organic aerosols (OA) globally and has significant impacts on climate and human health. The sources of WSOC remain very uncertain in polluted regions. Here we present a quantitative source apportionment of WSOC, isolated from aerosols in China using radiocarbon (14C) and offline high-resolution time-of-flight aerosol mass spectrometer measurements. Fossil emissions on average accounted for 32–47 % of WSOC. Secondary organic carbon (SOC) dominated both the non-fossil and fossil derived WSOC, highlighting the importance of secondary formation to WSOC in severe winter haze episodes. Contributions from fossil emissions to SOC were 61 ± 4 and 50 ± 9 % in Shanghai and Beijing, respectively, significantly larger than those in Guangzhou (36 ± 9 %) and Xi'an (26 ± 9 %). The most important primary sources were biomass burning emissions, contributing 17–26 % of WSOC. The remaining primary sources such as coal combustion, cooking and traffic were generally very small but not negligible contributors, as coal combustion contribution could exceed 10 %. Taken together with earlier 14C source apportionment studies in urban, rural, semi-urban and background regions in Asia, Europe and the USA, we demonstrated a dominant contribution of non-fossil emissions (i.e., 75 ± 11 %) to WSOC aerosols in the Northern Hemisphere; however, the fossil fraction is substantially larger in aerosols from East Asia and the eastern Asian pollution outflow, especially during winter, due to increasing coal combustion. Inclusion of our findings can improve a modelling of effects of WSOC aerosols on climate, atmospheric chemistry and public health.

scholarly journals Multidimensional Analytical Characterization of Water-Soluble Organic Aerosols: Challenges and New Perspectives

2021 ◽  
Vol 11 (6) ◽  
pp. 2539
Author(s):  
Regina M. B. O. Duarte ◽  
João T. V. Matos ◽  
Armando C. Duarte
Keyword(s):  
High Resolution ◽  
High Resolution Mass Spectrometry ◽  
Organic Aerosols ◽  
Analytical Techniques ◽  
Water Soluble ◽  
Chemical Complexity ◽  
Molecular Features ◽  
High Resolution Mass ◽  
Analytical Strategies ◽  
Resolution Mass

Water-soluble organic aerosols (OA) are an important component of air particles and one of the key drivers that impact both climate and human health. Understanding the processes involving water-soluble OA depends on how well the chemical composition of this aerosol component is decoded. Yet, obtaining detailed information faces several challenges, including water-soluble OA collection, extraction, and chemical complexity. This review highlights the multidimensional non-targeted analytical strategies that have been developed and employed for providing new insights into the structural and molecular features of water-soluble organic components present in air particles. First, the most prominent high-resolution mass spectrometric methods for near real-time measurements of water-soluble OA and their limitations are discussed. Afterward, a special emphasis is given to the degree of compositional information provided by offline multidimensional analytical techniques, namely excitation–emission (EEM) fluorescence spectroscopy, high-resolution mass spectrometry and two-dimensional nuclear magnetic resonance (NMR) spectroscopy and their hyphenation with chromatographic systems. The major challenges ahead on the application of these multidimensional analytical strategies for OA research are also addressed so that they can be used advantageously in future studies.

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