Aircraft observations of water-soluble dicarboxylic acids in the aerosols over China
Vertical profiles of dicarboxylic acids, related organic compounds and secondary organic aerosol (SOA) tracer compounds in particle phase have not yet been simultaneously explored in East Asia, although there is growing evidence that aqueous-phase oxidation of volatile organic compounds may be r...
| Main Authors: | , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-05-01
|
| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/16/6407/2016/acp-16-6407-2016.pdf |
| Summary: | Vertical profiles of dicarboxylic acids, related organic compounds and secondary organic aerosol
(SOA)
tracer compounds in particle phase have not yet been simultaneously explored
in East Asia, although there is growing evidence that aqueous-phase
oxidation of volatile organic compounds may be responsible for the elevated
organic aerosols (OA) in the troposphere. Here, we found consistently good
correlation of oxalic acid, the most abundant individual organic compounds
in aerosols globally, with its precursors as well as biogenic-derived
SOA compounds in Chinese tropospheric aerosols by aircraft
measurements. Anthropogenically derived dicarboxylic acids (i.e., C<sub>5</sub>
and C<sub>6</sub> diacids) at high altitudes were 4–20 times higher than those
from surface measurements and even occasionally dominant over oxalic acid at
altitudes higher than 2 km, which is in contrast to the predominance of
oxalic acid previously reported globally including the tropospheric and
surface aerosols. This indicates an enhancement of tropospheric SOA
formation from anthropogenic precursors. Furthermore, oxalic acid-to-sulfate
ratio maximized at altitudes of ∼ 2 km, explaining
aqueous-phase SOA production that was supported by good correlations
with predicted liquid water content, organic carbon and biogenic
SOA tracers. These results demonstrate that elevated oxalic acid and related
SOA compounds from both the anthropogenic and biogenic sources may
substantially contribute to tropospheric OA burden over polluted regions of
China, implying aerosol-associated climate effects and intercontinental
transport. |
|---|---|
| ISSN: | 1680-7316 1680-7324 |