scholarly journals Supplementary material to "Measurement report: Vertical distribution of biogenic and anthropogenic secondary organic aerosols in the urban boundary layer over Beijing during late summer"

2021 ◽  
Author(s):  
Hong Ren ◽  
Wei Hu ◽  
Lianfang Wei ◽  
Siyao Yue ◽  
Jian Zhao ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Vertical Distribution ◽  
Secondary Organic Aerosols ◽  
Organic Aerosols ◽  
Late Summer ◽  
Urban Boundary Layer ◽  
Supplementary Material

scholarly journals Measurement report: Vertical distribution of biogenic and anthropogenic secondary organic aerosols in the urban boundary layer over Beijing during late summer

2021 ◽  
Author(s):  
Hong Ren ◽  
Wei Hu ◽  
Lianfang Wei ◽  
Siyao Yue ◽  
Jian Zhao ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Chemistry ◽  
Secondary Organic Aerosols ◽  
Organic Aerosols ◽  
Late Summer ◽  
Urban Boundary Layer ◽  
Vertical Profiles ◽  
Emission Controls ◽  
Vertical Distributions ◽  
Modelling Studies

Abstract. Secondary organic aerosols (SOA) play a significant role in atmospheric chemistry. However, little is known about the vertical profiles of SOA in the urban boundary layer (UBL). This gap in the knowledge constrains the SOA simulation in chemical transport models. Here, we synchronously collected aerosol samples at 8 m, 120 m and 260 m based on a 325-m meteorological tower in urban Beijing from August 15th to September 10th, 2015. Strict emission controls were implemented during this period for the 2015 China Victory Day Parade. The sum of biogenic SOA tracers increased with height. The fraction of SOA from isoprene oxidation increased, whereas the fraction of monoterpene and sesquiterpene SOA decreased with height. The 2,3-dihydroxy-4-oxopentanoic acid (DHOPA), one tracer of anthropogenic SOA from toluene oxidation, also increased with height. The complicated vertical profiles of SOA tracers highlighted the needs to measure SOA within the UBL. The sum of estimated secondary organic carbon (SOC) ranged from 341 to 673 ngC m−3. The increase in the SOC fraction from isoprene and toluene with height was found to be more related to regional transport whereas the decrease in the SOC from monoterpene and sesquiterpene with height was more subject to local emissions. Emission controls during the parade reduced SOC by 4–35 % with toluene SOC decreasing more than the other SOC. This study demonstrates that vertical distributions of SOA within the UBL are complex, and the vertical profiles of SOA concentrations and sources should be considered in the future field and modelling studies.

Molecular characterization of size-segregated organic aerosols in the urban boundary layer in wintertime Beijing by FT-ICR MS

2021 ◽  
Author(s):  
Qiaorong Xie ◽  
Sihui Su ◽  
Shuang Chen ◽  
Qiang Zhang ◽  
Siyao Yue ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Size Distribution ◽  
Molecular Characterization ◽  
Organic Aerosols ◽  
Urban Boundary Layer ◽  
Vertical Profiles ◽  
Unique Information ◽  
Ft Icr Ms ◽  
Ft Icr

Our study provides unique information on the vertical profiles and size distribution of urban organic aerosols by FT-ICR MS.

scholarly journals Measurement report: Vertical distribution of atmospheric particulate matter within the urban boundary layer in southern China – size-segregated chemical composition and secondary formation through cloud processing and heterogeneous reactions

2020 ◽  
Vol 20 (11) ◽  
pp. 6435-6453 ◽  
Author(s):  
Shengzhen Zhou ◽  
Luolin Wu ◽  
Junchen Guo ◽  
Weihua Chen ◽  
Xuemei Wang ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Particulate Matter ◽  
Vertical Distribution ◽  
Aqueous Phase ◽  
Ground Level ◽  
Urban Boundary Layer ◽  
Water Soluble ◽  
Heterogeneous Reactions ◽  
Formation Mechanisms ◽  
Autumn And Winter

Abstract. Many studies have recently been done on understanding the sources and formation mechanisms of atmospheric aerosols at ground level. However, vertical profiles and sources of size-resolved particulate matter within the urban boundary layer are still lacking. In this study, vertical distribution characteristics of size-segregated particles were investigated at three observation platforms (ground level, 118 m, and 488 m) on the 610 m high Canton Tower in Guangzhou, China. Size-segregated aerosol samples were simultaneously collected at the three levels in autumn and winter. Major aerosol components, including water-soluble ions, organic carbon, and elemental carbon, were measured. The results showed that daily average fine-particle concentrations generally decreased with height. Concentrations of sulfate and ammonium in fine particles displayed shallow vertical gradients, and nitrate concentrations increased with height in autumn, while the chemical components showed greater variations in winter than in autumn. The size distributions of sulfate and ammonium in both seasons were characterized by a dominant unimodal mode with peaks in the size range of 0.44–1.0 µm. In autumn, the nitrate size distribution was bimodal, peaking at 0.44–1.0 and 2.5–10 µm, while in winter it was unimodal, implying that the formation mechanisms for nitrate particles were different in the two seasons. Our results suggest that the majority of the sulfate and nitrate is formed from aqueous-phase reactions, and we attribute coarse-mode nitrate formation at the measurement site to the heterogeneous reactions of gaseous nitric acid on existing sea-derived coarse particles in autumn. Case studies further showed that atmospheric aqueous-phase and heterogeneous reactions could be important mechanisms for sulfate and nitrate formation, which, in combination with adverse weather conditions such as temperature inversion and calm wind, led to haze formation during autumn and winter in the Pearl River Delta (PRD) region.

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