Marine nanogels as a source of atmospheric nanoparticles in the high Arctic

Abstract

The high Arctic (north of 80°N) in summer is a region characterized by clean air and low abundances of preexisting particles. Marine colloidal nanogels i.e., assembled dissolved organic carbohydrate polymer networks have recently been confirmed to be present in both airborne particles and cloud water over the Arctic pack ice area. A novel route to atmospheric nanoparticles that appears to be operative in the high Arctic is suggested. It involves the injection of marine granular nanogels into the air from evaporating fog and cloud droplets, and is supported by observational and theoretical evidence obtained from a case study. Statistical analysis of the aerosol size distribution data recorded in the years 1991, 1996, 2001, and 2008 classified 75 nanoparticle events - covering 17% of the observed time period - as nanogel-type events, characterized by the spontaneous appearance of several distinct size bands below 200 nm diameter.