Process-based and observation-constrained SOA simulations in China: the role of semivolatile and intermediate-volatility organic compounds and OH levels
<p>Organic aerosol (OA) is a major component of tropospheric submicron aerosol that contributes to air pollution and causes adverse effects on human health. Chemical transport models have difficulties in reproducing the variability in OA concentrations in polluted areas, hindering understandin...
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| Autores principales: | , , , , , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
Copernicus Publications
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/4009ba894fa843e9b03b99578cd6bd35 |
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| Sumario: | <p>Organic aerosol (OA) is a major component of tropospheric submicron aerosol that contributes to air pollution and causes adverse effects on human
health. Chemical transport models have difficulties in reproducing the variability in OA concentrations in polluted areas, hindering understanding
of the OA budget and sources. Herein, we apply both process-based and observation-constrained schemes to simulate OA in GEOS-Chem. Comprehensive
data sets of surface OA, OA components, secondary organic aerosol (SOA) precursors, and oxidants were used for model–observation comparisons. The
base models generally underestimate the SOA concentrations in China. In the revised schemes, updates were made on the emissions, volatility
distributions, and SOA yields of semivolatile and intermediate-volatility organic compounds (SVOCs and IVOCs) and additional nitrous acid sources. With all
the model improvements, both the process-based and observation-constrained SOA schemes can reproduce the observed mass concentrations of SOA and
show spatial and seasonal consistency with each other. Our best model simulations suggest that anthropogenic SVOCs and IVOCs are the dominant source of SOA,
with a contribution of over 50 % in most of China, which should be considered for pollution mitigation in the future. The residential sector may
be the predominant source of SVOCs and IVOCs in winter, despite large uncertainty remaining in the emissions of IVOCs from the residential sector in northern
China. The industry sector is also an important source of IVOCs, especially in summer. More SVOC and IVOC measurements are needed to constrain their
emissions. Besides, the results highlight the sensitivity of SOA to hydroxyl radical (OH) levels in winter in polluted environments. The addition of
nitrous acid sources can lead to over 30 % greater SOA mass concentrations in winter in northern China. It is important to have good OH
simulations in air quality models.</p> |
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