Secondary Organic Aerosol Production via Ozonolysis of Green Leaf Volatiles

Conference Year

January 2019

Abstract

Aerosols are ubiquitous in the atmosphere and play important roles in environmental processes. Secondary organic aerosols (SOA) in particular are produced via gas phase oxidation reactions of volatile organic compounds (VOCs). Recently, focus has shifted to green leaf volatiles (GLVs; a subset of VOCs), which have the potential to contribute significantly to the overall SOA budget. Here, investigations of the ozonolysis of relevant GLV SOA precursors cis-3-hexenyl acetate (CHA) and cis-3-hexenol (HXL) are presented. Specifically, a Scanning Mobility Particle Sizer (SMPS), Electrical Low Pressure Impactor (ELPI), and Near-Infrared Laser Desorption-Ionization Aerosol Mass Spectrometer (NIR-LDI-AMS) were utilized to probe both physical and chemical properties of SOA formed in the University of Vermont Environmental Chamber (UVMEC) under dry (relative humidity, RH <2%) and humid (82%< RH <90%) conditions. Results suggest the presence of oxidation pathways allowing for the production of highly oxygenated SOA products in addition to prominent oligomers, both exhibiting partial non-liquid characteristics. In contrast to the CHA and HXL derived SOA produced under dry conditions, SOA produced under high RH conditions exhibited larger particle diameters, lower mass loadings, and increased prevalence of lower molecular weight products, while the relative phase remained similar. These findings have important implications for the distribution, abundance, and transport of atmospheric gases, as well as Earth’s radiative budget via light scattering, light absorbance, and cloud formation.

Primary Faculty Mentor Name

Giuseppe Petrucci

Faculty/Staff Collaborators

Christopher Snyder

Status

Graduate

Student College

College of Arts and Sciences

Program/Major

Chemistry

Primary Research Category

Engineering & Physical Sciences

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Secondary Organic Aerosol Production via Ozonolysis of Green Leaf Volatiles

Aerosols are ubiquitous in the atmosphere and play important roles in environmental processes. Secondary organic aerosols (SOA) in particular are produced via gas phase oxidation reactions of volatile organic compounds (VOCs). Recently, focus has shifted to green leaf volatiles (GLVs; a subset of VOCs), which have the potential to contribute significantly to the overall SOA budget. Here, investigations of the ozonolysis of relevant GLV SOA precursors cis-3-hexenyl acetate (CHA) and cis-3-hexenol (HXL) are presented. Specifically, a Scanning Mobility Particle Sizer (SMPS), Electrical Low Pressure Impactor (ELPI), and Near-Infrared Laser Desorption-Ionization Aerosol Mass Spectrometer (NIR-LDI-AMS) were utilized to probe both physical and chemical properties of SOA formed in the University of Vermont Environmental Chamber (UVMEC) under dry (relative humidity, RH <2%) and humid (82%< RH <90%) conditions. Results suggest the presence of oxidation pathways allowing for the production of highly oxygenated SOA products in addition to prominent oligomers, both exhibiting partial non-liquid characteristics. In contrast to the CHA and HXL derived SOA produced under dry conditions, SOA produced under high RH conditions exhibited larger particle diameters, lower mass loadings, and increased prevalence of lower molecular weight products, while the relative phase remained similar. These findings have important implications for the distribution, abundance, and transport of atmospheric gases, as well as Earth’s radiative budget via light scattering, light absorbance, and cloud formation.