title: Secondary Organic Aerosol Formation over Coastal Ocean: Inferences from Atmospheric Water-Soluble Low Molecular Weight Organic Compounds.
abstract: A lack of consensus on the distributions and formation pathways of secondary organic aerosols (SOA) over oceanic regions downwind of pollution sources limits our ability to assess their climate impact globally. As a case study, we report here on water-soluble SOA components such as dicarboxylic acids, oxocarboxylic acids, and α-dicarbonyls in the continental outflows from the Indo-Gangetic Plain (IGP) and Southeast Asia (SEA) to the Bay of Bengal. Oxalic acid (C2) is the dominant species followed by succinic (C4) and glyoxylic acids (ωC2) in the outflow. Nonsea-salt SO42-also dominates (∼70%) total water-soluble inorganic constituents and correlates well with aerosol liquid water content (LWC) and C2, indicating their production through aqueous phase photochemical reactions. Furthermore, mass ratios of dicarboxylic acids (C2/C4, C2/ωC2), and their relative abundances in water-soluble organic carbon and total organic carbon are quite similar between the two continental (IGP and SEA) outflows, indicating the formation of SOA through aqueous phase photochemical reactions in LWC-enriched aerosols, largely controlled by anthropogenic SO42-.
authors.affiliation: Institute of Low Temperature Science, Hokkaido University , Sapporo 060-0819, Japan.|Physical Research Laboratory , Navrangpura, Ahmedabad 380009, India.
authors.forename: Srinivas
authors.identifier: 0000-0001-8519-012X
authors.initials: S
authors.lastname: Bikkina
authors.affiliation: Institute of Low Temperature Science, Hokkaido University , Sapporo 060-0819, Japan.
authors.forename: Kimitaka
authors.initials: K
authors.lastname: Kawamura
authors.affiliation: Physical Research Laboratory , Navrangpura, Ahmedabad 380009, India.
authors.forename: Manmohan
authors.initials: M
authors.lastname: Sarin
mesh_terms: D000336:Aerosols; D000393:Air Pollutants; D004784:Environmental Monitoring; D008970:Molecular Weight; D009792:Oceans and Seas; D014867:Water
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D014867:Water