Open AccessChemical speciation of sulfur in marine cloud droplets and particles: Analysis of individual particles from the marine boundary layer over the California current
Author(s) -
Hopkins Rebecca J.,
Desyaterik Yury,
Tivanski Alexei V.,
Zaveri Rahul A.,
Berkowitz Carl M.,
Tyliszczak Tolek,
Gilles Mary K.,
Laskin Alexander
Publication year - 2008
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2007jd008954
Subject(s) - aerosol , sulfate , microanalysis , sea salt , chemical composition , seawater , xanes , sulfur , mineralogy , analytical chemistry (journal) , mass spectrometry , materials science , environmental chemistry , chemistry , spectroscopy , geology , oceanography , chromatography , physics , quantum mechanics , metallurgy , organic chemistry
Detailed chemical speciation of the dry residue particles from individual cloud droplets and interstitial aerosol collected during the Marine Stratus Experiment (MASE) was performed using a combination of complementary microanalysis techniques. Techniques include computer controlled scanning electron microscopy with energy dispersed analysis of X rays (CCSEM/EDX), time‐of‐flight secondary ionization mass spectrometry (TOF‐SIMS), and scanning transmission X‐ray microscopy with near edge X‐ray absorption fine structure spectroscopy (STXM/NEXAFS). Samples were collected at the ground site located in Point Reyes National Seashore, approximately 1 km from the coast. This manuscript focuses on the analysis of individual particles sampled from air masses that originated over the open ocean and then passed through the area of the California current located along the northern California coast. On the basis of composition, morphology, and chemical bonding information, two externally mixed, distinct classes of sulfur containing particles were identified: chemically modified (aged) sea salt particles and secondary formed sulfate particles. The results indicate substantial heterogeneous replacement of chloride by methanesulfonate (CH 3 SO 3 − ) and non‐sea‐salt sulfate (nss‐SO 4 2− ) in sea‐salt particles with characteristic ratios of nss‐S/Na > 0.10 and CH 3 SO 3 − /nss‐SO 4 2− > 0.6.