Review status: this preprint is currently under review for the journal ACP.
Measurement report: Vertical distribution of biogenic and
anthropogenic secondary organic aerosols in the urban boundary
layer over Beijing during late summer
1Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
2State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
3Chubu Institute for Advanced Studies, Chubu University, Kasugai 487-8501, Japan
anow at: Minerva Research Group, Max Planck Institute for Chemistry, Mainz 55128, Germany
bnow at: Department of Chemistry and Molecular Biology, University of Gothenburg, 412 96, Gothenburg, Sweden
1Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
2State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
3Chubu Institute for Advanced Studies, Chubu University, Kasugai 487-8501, Japan
anow at: Minerva Research Group, Max Planck Institute for Chemistry, Mainz 55128, Germany
bnow at: Department of Chemistry and Molecular Biology, University of Gothenburg, 412 96, Gothenburg, Sweden
Received: 16 Feb 2021 – Accepted for review: 17 Feb 2021 – Discussion started: 19 Feb 2021
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.
This study presents vertical profiles of biogenic and anthropogenic secondary organic aerosols (SOA) in the urban boundary layer based on a 325-m tower in Beijing in late summer. The increases in the isoprene and toluene SOA with height were found to be more related to regional transport whereas the decrease in those from monoterpenes and sesquiterpene were more subject to local emissions. Such complicated vertical distributions of SOA should be considered in future modeling work.
This study presents vertical profiles of biogenic and anthropogenic secondary organic aerosols...
