Photooxidation of cyclohexene in the presence of SO<sub>2</sub>: SOA yield and chemical composition
Secondary organic aerosol (SOA) formation from a cyclohexene ∕ NO<sub><i>x</i></sub> system with various SO<sub>2</sub> concentrations under UV light was investigated to study the effects of cyclic alkenes on the atmospheric environment in polluted urban areas....
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-11-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/17/13329/2017/acp-17-13329-2017.pdf |
| Summary: | Secondary organic aerosol (SOA) formation from a cyclohexene ∕ NO<sub><i>x</i></sub> system
with various SO<sub>2</sub> concentrations under UV light was investigated to study
the effects of cyclic alkenes on the atmospheric environment in polluted
urban areas. A clear decrease at first and then an increase in the SOA yield was
found with increasing SO<sub>2</sub> concentrations. The lowest SOA yield was
obtained when the initial SO<sub>2</sub> concentration was in the range of
30–40 ppb, while higher SOA yield compared to that without SO<sub>2</sub> could
not be obtained until the initial SO<sub>2</sub> concentration was higher than
85 ppb. The decreasing SOA yield might be due to the fact that the promoting
effect of acid-catalysed reactions on SOA formation was less important than
the inhibiting effect of decreasing OH concentration at low initial SO<sub>2</sub>
concentrations, caused by the competition reactions of OH with SO<sub>2</sub> and
cyclohexene. The competitive reaction was an important factor for SOA yield
and it should not be neglected in photooxidation reactions. The composition
of organic compounds in SOA was measured using several complementary
techniques including Fourier transform infrared (FTIR) spectroscopy, ion
chromatography (IC), and Exactive Plus Orbitrap mass spectrometer equipped with
electrospray interface (ESI). We present new evidence that organosulfates
were produced from the photooxidation of cyclohexene in the presence of
SO<sub>2</sub>. |
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| ISSN: | 1680-7316 1680-7324 |