Simulation of atmospheric organic aerosol using its volatility–oxygen-content distribution during the PEGASOS 2012 campaign
<p>A lot of effort has been made to understand and constrain the atmospheric aging of the organic aerosol (OA). Different parameterizations of the organic aerosol formation and evolution in the two-dimensional volatility basis set (2D-VBS) framework are evaluated using ground and airborne...
Main Authors: | , , , , , , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2018-07-01
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Series: | Atmospheric Chemistry and Physics |
Online Access: | https://www.atmos-chem-phys.net/18/10759/2018/acp-18-10759-2018.pdf |
Summary: | <p>A lot of effort has been made to understand and constrain the
atmospheric aging of the organic aerosol (OA). Different parameterizations of
the organic aerosol formation and evolution in the two-dimensional volatility
basis set (2D-VBS) framework are evaluated using ground and airborne
measurements collected in the 2012 Pan-European Gas
AeroSOls-climate interaction Study (PEGASOS) field campaign in the Po
Valley (Italy). A number of chemical aging schemes are examined, taking into
account various functionalization and fragmentation pathways for biogenic and
anthropogenic OA components. Model predictions and measurements, both at the
ground and aloft, indicate a relatively oxidized OA with little average
diurnal variation. Total OA concentration and O : C ratios
are reproduced within experimental error by a number of chemical aging
schemes. Anthropogenic secondary OA (SOA) is predicted to contribute
15–25 % of the total OA, while SOA from intermediate volatility
compound oxidation contributes another 20–35 %. Biogenic SOA (bSOA) contributions varied
from 15 to 45 % depending on the modeling scheme. Primary OA contributed
around 5 % for all schemes and was comparable to the hydrocarbon-like
OA (HOA) concentrations derived from the positive matrix factorization of the
aerosol mass spectrometer (PMF-AMS) ground measurements. The average OA and
O : C diurnal variation and their vertical profiles showed
a surprisingly modest sensitivity to the assumed vaporization enthalpy for
all aging schemes. This can be explained by the interplay between the
partitioning of the semi-volatile compounds and their gas-phase chemical
aging reactions.</p> |
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ISSN: | 1680-7316 1680-7324 |