Size resolved morphological properties of the high Arctic summer aerosol during ASCOS-2008

Abstract

<p><strong>Abstract.</strong> The representation of aerosol properties and processes in climate models is fraught with large uncertainties. Especially at high northern latitudes a strong under-prediction of aerosol concentrations and nucleation events is observed and can only be constrained by in situ observations based on the analysis of individual aerosol particles. To further reduce the uncertainties surrounding aerosol properties and their potential role as cloud condensation nuclei this study provides observational data resolved over size on morphological and chemical properties of aerosol particles collected in the summer high Arctic, north of 80° N. Aerosol particles were imaged with scanning and transmission electron microscopy and further evaluated with digital image analysis. In total 3903 particles were imaged and categorized according to morphological similarities into three gross morphological groups, single particles, gel particles and halo particles. Single particles were observed between 15 nm and 800 nm in diameter and represent the dominating type of particles (82%). The majority of particles appeared to be marine gels with a broad Aitken mode peaking at 70 nm accompanied by a minor fraction of ammonium (bi)sulfate with a maximum in number concentration at 170 nm. Gel particles (11% of all particles) were observed between 45 nm and 800 nm with a maximum in number concentration at 154 nm. Imaging with transmission electron microscopy allowed further morphological discrimination of gel particles in “<i>aggregate</i>” particles, “<i>aggregate with film</i>” particles and “<i>mucus-like</i>” particles.</p>

Saccharide Transfer to Sea Spray Aerosol Enhanced by Surface Activity, Calcium, and Protein Interactions

“…72 Further, colloidal and aggregate phytoplankton material often comprises marine aerosol organic. 9,18,26,104 Addition of the protein BSA yielded the greatest EF enhancement found in this study, further highlighting the importance of the seawater matrix in enhancing saccharide transfer to aerosol. To further evaluate saccharide transfer in complex matrices, studies with additional polysaccharides, proteins, and other molecular compounds, in particular, those that are surface active, are needed.…”

Frequent new particle formation over the high Arctic pack ice by enhanced iodine emissions

“…Previous measurements in the region have revealed a number of CCN sources, including secondary marine organic particles, primary marine emissions like sea salt and organic aerosol, longrange transported continental emissions and their down-mixing into the marine boundary layer from aloft [7][8][9][10] . Continental influence may make up about one-third of the non-refractory accumulation mode particles 7 , highlighting the importance of regional and local Arctic sources which are not yet well constrained.…”

Morphology, Chemical Composition and Mixing State of Atmospheric Aerosols from Two Contrasting Environments in Southern India

“…The subdued presence of Sulphur could be due to the evaporation of highly volatile sulphate aerosols in the high vacuum SEM environment (Ikegami et al, 1980;Ono et al, 1983;Deboudt et al, 2010). A recent study by Hamacher-Barth et al (2016) reported that sulphate particles when exposed under SEM evaporated within a timescale of a few minutes. It is further noted that: 5 a) For both BLR and CHK, the sum of C% and dust% (Si, oxides and other dust origin elements) across the collected samples remained almost constant.…”