Liquid sea salt aerosol production via blowing snow: field and laboratory results

Deployment of the aerosol mass spectrometer (AMS) to the field presents a unique opportunity for studying sources and trends of ambient aerosol species because of its high temporal resolution for aerosol composition. The AMS was used to study the pristine Antarctic atmosphere for the first time during the 2ODIAC campaign in 2014 and 2015. Traditional AMS data analysis quantifies only non-refractory species (those that vaporize at 600°C), excluding sea salt, mineral dust, black carbon, and others. Semi-refractory species can be analyzed by examining the slow vaporization of these compounds from the AMS vaporizer. During the 2ODIAC campaign, episodic semi-refractory chloride enhancements were observed in the field, correlating with increases in wind speed and observations of blowing snow. During these blowing snow events, the ratio of fast to slow vaporizing chloride signal increased, indicating a potential difference in aerosol phase. Laboratory investigations of wet and dry NaCl particles indicate a similar fast vaporization enhancement for wet NaCl particles. Slow vaporization profiles of laboratory particles were investigated using a variety of functional fits, with a double exponential model chosen as the best model. This investigation showed that liquid laboratory particles exhibit faster vaporization time scales than dry. Concentration enhancements in the fast vaporization signal of approximately 30% were observed for wet particles under similar conditions as dry particles. This work highlights the potential of the AMS to identify phase difference for semi-refractory components in polar aerosol.