title: Effect of Structural Heterogeneity in Chemical Composition on Online Single-Particle Mass Spectrometry Analysis of Sea Spray Aerosol Particles.
abstract: Knowledge of the surface composition of sea spray aerosols (SSA) is critical for understanding and predicting climate-relevant impacts. Offline microscopy and spectroscopy studies have shown that dry supermicron SSA tend to be spatially heterogeneous particles with sodium- and chloride-rich cores surrounded by organic enriched surface layers containing minor inorganic seawater components such as magnesium and calcium. At the same time, single-particle mass spectrometry reveals several different mass spectral ion patterns, suggesting that there may be a number of chemically distinct particle types. This study investigates factors controlling single particle mass spectra of nascent supermicron SSA. Depth profiling experiments conducted on SSA generated by a fritted bubbler and total ion intensity analysis of SSA generated by a marine aerosol reference tank were compared with observations of ambient SSA observed at two coastal locations. Analysis of SSA produced by utilizing controlled laboratory methods reveals that single-particle mass spectra with weak sodium ion signals can be produced by the desorption of the surface of typical dry SSA particles composed of salt cores and organic-rich coatings. Thus, this lab-based study for the first time unifies findings from offline and online measurements as well as lab and field studies of the SSA particle-mixing state.
authors.affiliation: Department of Chemistry and Biochemistry and ‡Scripps Institution of Oceanography, University of California , San Diego, La Jolla, California 92093, United States.
authors.forename: Camille M
authors.identifier: 0000-0003-4038-5518
authors.initials: CM
authors.lastname: Sultana
authors.affiliation: Department of Chemistry and Biochemistry and ‡Scripps Institution of Oceanography, University of California , San Diego, La Jolla, California 92093, United States.
authors.forename: Douglas B
authors.identifier: 0000-0002-6248-9644
authors.initials: DB
authors.lastname: Collins
authors.affiliation: Department of Chemistry and Biochemistry and ‡Scripps Institution of Oceanography, University of California , San Diego, La Jolla, California 92093, United States.
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Prather
mesh_terms: D000336:Aerosols; D013058:Mass Spectrometry; D010316:Particle Size; D012623:Seawater / Q000737:chemistry; D012965:Sodium Chloride / Q000737:chemistry; D013057:Spectrum Analysis
chemical_list: D000336:Aerosols; D012965:Sodium Chloride