Oligomer and highly oxygenated organic molecule formation from oxidation of oxygenated monoterpenes emitted by California sage plants
<p>Plants emit a diverse range of biogenic volatile organic compounds (BVOCs) whose oxidation leads to secondary organic aerosol (SOA) formation. The majority of studies of biogenic SOA have focused on single or simple multicomponent BVOC mixtures thought to be representative of Northern hemis...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-09-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/20/10953/2020/acp-20-10953-2020.pdf |
| Summary: | <p>Plants emit a diverse range of biogenic volatile organic compounds (BVOCs)
whose oxidation leads to secondary organic aerosol (SOA) formation. The
majority of studies of biogenic SOA have focused on single or simple
multicomponent BVOC mixtures thought to be representative of Northern
hemispheric deciduous or mixed forest conditions. Gaps remain in our
understanding of SOA formation from complex mixtures of real plant emissions
in other environments.</p>
<p>Towards the goal of understanding SOA in other regions, we conducted the
first comprehensive study of SOA from oxygenated monoterpenes. These are the
dominant emissions from the most common plant species in southern
California's coastal sage ecosystem: black sage (<i>Salvia mellifera</i>) and California sagebrush
(<i>Artemisia californica</i>).</p>
<p>Emissions from sage plants, as well as single compounds representing their major
emissions (camphor, camphene and eucalyptol), were oxidised in an Aerodyne
potential aerosol mass oxidation flow reactor (PAM-OFR). The chemical
composition of SOA was characterised using a high-resolution time-of-flight
iodide-anion chemical-ionisation mass spectrometer equipped with a Filter
Inlet for Gases and AEROsols (FIGAERO-I-HR-ToF-CIMS) under low- and
medium-<span class="inline-formula">NO<sub><i>x</i></sub></span> conditions.</p>
<p>SOA from oxygenated monoterpenes showed a higher-order oligomer content and a
greater presence of highly oxygenated organic molecules (HOMs) than
non-oxygenated monoterpenes, with HOM contributing 27 %–47 % and 12 %–14 % of SOA product signal from oxygenated and non-oxygenated monoterpenes
respectively. This study highlights the potential importance of oxygenated
monoterpene emissions for SOA formation in woody shrub ecosystems.</p> |
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| ISSN: | 1680-7316 1680-7324 |