scholarly journals Molecular Characterization and Seasonal Variation in Primary and Secondary Organic Aerosols in Beijing, China

2018 ◽  
Vol 123 (21) ◽  
pp. 12,394-12,412 ◽  
Author(s):  
Linjie Li ◽  
Lujie Ren ◽  
Hong Ren ◽  
Siyao Yue ◽  
Qiaorong Xie ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Molecular Characterization ◽  
Secondary Organic Aerosols ◽  
Organic Aerosols ◽  
Beijing China

scholarly journals Secondary Organic Aerosols in PM2.5 in Bengbu, a Typical City in Central China: Concentration, Seasonal Variation and Sources

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 854
Author(s):  
Shiwei Zhang ◽  
Hao Tang ◽  
Qing Li ◽  
Liang Li ◽  
Chaojun Ge ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Organic Carbon ◽  
Secondary Organic Aerosols ◽  
Organic Aerosols ◽  
Average Concentration ◽  
Water Soluble ◽  
Central China ◽  
Urban Site ◽  
Formation Mechanisms ◽  
Pollution Levels

To investigate the concentration, seasonal variation, and sources of secondary organic aerosols (SOAs) in the inland areas of central China, 244 seasonal PM2.5 samples were collected from January to October 2019 at one urban site and one suburban site simultaneously in Bengbu of Anhui Province. Concentrations of organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), and typical organic tracers, including saccharides, tracers of SOAs from isoprene, terpenes, and toluene, were measured. Results showed that Bengbu has high pollution levels of organic aerosols, with annual average OC concentrations of about 9.5 μg m−3. About 60% of the OC in PM2.5 in Bengbu was water soluble. Different seasonal trends were found for the SOA tracers of isoprene, monoterpene, seisquiterpene, and toluene. The highest seasonal average concentration of the isoprene SOA tracers was observed in summer and of the monoterpene and seisquiterpene SOA tracers in autumn. A stronger correlation was found between the 2-methylglyceric acid-to-2-methyltetrol ratio (MGA/MTL) and ambient temperature than that between MGA/MTLs and NOX concentration, suggesting that temperature has an important impact on the MGA/MTL ratio besides NOX concentration. The OC/EC-based method, WSOC-based method, tracer yield method, and positive matrix factorization (PMF)-based method were used to estimate the concentration and sources of secondary organic carbon (SOC), and the PMF-based method was believed to be able to give reasonable results. SOC was the main contributor of WSOC in PM2.5 in Bengbu, while biomass burning made an important contribution to WSOC in autumn and winter (~40%). SOC was mainly associated with SOA tracers in summer and mainly associated with secondary ions in spring and winter, suggesting different formation mechanisms in different seasons.

scholarly journals Large Discrepancy in the Formation of Secondary Organic Aerosols from Structurally Similar Monoterpenes

2021 ◽  
Vol 5 (3) ◽  
pp. 632-644
Author(s):  
Ditte Thomsen ◽  
Jonas Elm ◽  
Bernadette Rosati ◽  
Jane Tygesen Skønager ◽  
Merete Bilde ◽  
...  
Keyword(s):  
Secondary Organic Aerosols ◽  
Organic Aerosols

scholarly journals Aerosol chemical and optical properties over the Paris area within ESQUIF project

2006 ◽  
Vol 6 (11) ◽  
pp. 3257-3280 ◽  
Author(s):  
A. Hodzic ◽  
R. Vautard ◽  
P. Chazette ◽  
L. Menut ◽  
B. Bessagnet
Keyword(s):  
Optical Properties ◽  
Secondary Organic Aerosols ◽  
Organic Aerosols ◽  
Dust Particles ◽  
Aerosol Size Distribution ◽  
Aerosol Composition ◽  
Aerosol Mass ◽  
Coarse Mode ◽  
Paris Area ◽  
Flight Trajectories

Abstract. Aerosol chemical and optical properties are extensively investigated for the first time over the Paris Basin in July 2000 within the ESQUIF project. The measurement campaign offers an exceptional framework to evaluate the performances of the chemistry-transport model CHIMERE in simulating concentrations of gaseous and aerosol pollutants, as well as the aerosol-size distribution and composition in polluted urban environments against ground-based and airborne measurements. A detailed comparison of measured and simulated variables during the second half of July with particular focus on 19 and 31 pollution episodes reveals an overall good agreement for gas-species and aerosol components both at the ground level and along flight trajectories, and the absence of systematic biases in simulated meteorological variables such as wind speed, relative humidity and boundary layer height as computed by the MM5 model. A good consistency in ozone and NO concentrations demonstrates the ability of the model to reproduce the plume structure and location fairly well both on 19 and 31 July, despite an underestimation of the amplitude of ozone concentrations on 31 July. The spatial and vertical aerosol distributions are also examined by comparing simulated and observed lidar vertical profiles along flight trajectories on 31 July and confirm the model capacity to simulate the plume characteristics. The comparison of observed and modeled aerosol components in the southwest suburb of Paris during the second half of July indicates that the aerosol composition is rather correctly reproduced, although the total aerosol mass is underestimated by about 20%. The simulated Parisian aerosol is dominated by primary particulate matter that accounts for anthropogenic and biogenic primary particles (40%), and inorganic aerosol fraction (40%) including nitrate (8%), sulfate (22%) and ammonium (10%). The secondary organic aerosols (SOA) represent 12% of the total aerosol mass, while the mineral dust accounts for 8%. The comparison demonstrates the absence of systematic errors in the simulated sulfate, ammonium and nitrates total concentrations. However, for nitrates the observed partition between fine and coarse mode is not reproduced. In CHIMERE there is a clear lack of coarse-mode nitrates. This calls for additional parameterizations in order to account for the heterogeneous formation of nitrate onto dust particles. Larger discrepancies are obtained for the secondary organic aerosols due to both inconsistencies in the SOA formation processes in the model leading to an underestimation of their mass and large uncertainties in the determination of the measured aerosol organic fraction. The observed mass distribution of aerosols is not well reproduced, although no clear explanation can be given.

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