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Title: Secondary organic aerosols derived from intermediate-volatility n-alkanes adopt low-viscous phase state
Abstract. Secondary organic aerosol (SOA) derived from n-alkanes, as emitted from vehicles and volatile chemical products, is a major component of anthropogenic particulate matter, yet the chemical composition and phase state are poorly understood and thus poorly constrained in aerosol models. Here we provide a comprehensive analysis of n-alkane SOA by explicit gas-phase chemistry modeling, machine learning, and laboratory experiments to show that n-alkane SOA adopts low-viscous semi-solid or liquid states. Our study underlines the complex interplay of molecular composition and SOA viscosity: n-alkane SOA with a higher carbon number mostly consists of less functionalized first-generation products with lower viscosity, while the SOA with a lower carbon number contains more functionalized multigenerational products with higher viscosity. This study opens up a new avenue for analysis of SOA processes, and the results indicate few kinetic limitations of mass accommodation in SOA formation, supporting the application of equilibrium partitioning for simulating n-alkane SOA formation in large-scale atmospheric models.  more » « less
Award ID(s):
1750447
PAR ID:
10586805
Author(s) / Creator(s):
; ; ; ; ; ;
Publisher / Repository:
Copernicus Publications, European Geosciences Union
Date Published:
Journal Name:
Atmospheric Chemistry and Physics
Volume:
24
Issue:
9
ISSN:
1680-7324
Page Range / eLocation ID:
5549 to 5565
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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