Effect of structural heterogeneity in chemical composition on online single-particle mass spectrometry analysis of sea spray aerosol particles

Citation:
Sultana, CM, Collins DB, Prather KA.  2017.  Effect of structural heterogeneity in chemical composition on online single-particle mass spectrometry analysis of sea spray aerosol particles. Environmental Science & Technology. 51:3660-3668.

Date Published:

2017/04

Keywords:

Aerosols, atmospheric particles, behavior, bubble, cloud condensation nuclei, hygroscopic, marine aerosol, mixing state, primary organic aerosol, raman microspectroscopy, salt droplets, tropospheric

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 fitted 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.

Notes:

n/a

Website

DOI:

10.1021/acs.est.6b06399