Ozonolysis Chemistry and Phase Behavior of 1-Octen-3-ol-Derived Secondary Organic Aerosol

Abstract

Secondary organic aerosol (SOA) is ubiquitous in the atmosphere and plays important roles in environmental chemical processes, influencing air quality and the Earth’s radiative budget. In the present work, 1-octen-3-ol (OTL) was identified as one of several prominent green leaf volatiles (GLVs) emitted as a result of sugarcane wounding. GLVs, a subset of volatile organic compounds (VOCs), act as SOA precursors and are a potentially underrepresented source of the overall SOA budget. Here, ozonolysis experiments of OTL standards were carried out in Teflon chambers in conjunction with a scanning mobility particle sizer (SMPS), an electrical low pressure impactor (ELPI+), and a near-infrared laser desorption ionization aerosol mass spectrometer (NIR-LDI-AMS). Under our experimental conditions, the OTL ozonolysis rate constant and aerosol yield were estimated to be 5.00 ± 0.58 × 10–24 cm3 s–1 molecule–1 and 1.03 ± 0.07%, respectively. Bounce factor (BF) calculations based on the ELPI+ data at relative humidity (RH) levels of 5, 30, 60, and 90% suggest that the OTL-derived SOA exhibits largely non-liquid characteristics regardless of RH levels at particle genesis. Furthermore, high RH at particle genesis also appears to decrease the hygroscopicity of the SOA, impacting its ability to activate as cloud droplets. Online chemical analysis of the SOA using a NIR-LDI-AMS supports the production of oxygenated products ranging from 45 to 161 m/z, in addition to prominent oligomers well beyond this m/z range.

Green Leaf Volatiles in the Atmosphere—Properties, Transformation, and Significance

“…Plants release GLV when attacked by animals, insects, and microbes or exposed to abiotic stress or mechanical wounding [16,27,35,43,48,73,74]. For instance, trees and shrubs emitted (E)-2-hexenal upon wounding and in response to bacterial pathogenesis [6].…”

“…[81]. • 0.6 ± 0.1 µg g −1 h −1 cut sugarcane in a chamber [48]. 0.12 ± 0.07, 0.35 ± 0.17 ng g (foliage) −1 h −1 blue ash, white fingertree [40].…”

“…Fischer et al [48] determined the (1.03 ± 0.07%) SOA mass yields from gas-phase ozonolysis of 1-octen-3-ol in two Teflon chambers (see Section 4.2.3) equipped with scanning mobility particle sizers and electrical low power impactors. Ozone and 1-octen-3-ol mixing ratios were 200 ppb.…”

“…Both compounds originated from the gas-phase ozonolysis of (Z)-3-hexenyl acetate. The formation of several particle-phase products from 1-octen-3-ol through Criegee intermediates was proposed based on AMS analyses of SOA (Scheme 53) [48]. Scheme 53.…”

“…Scheme 53. Mechanism of multiphase ozonolysis of 1-octen-3-ol in a smog chamber [48]. Products with specified MW values were identified in chamber SOA samples using NIR-LDI-AMS approach.…”