Heterogeneous Chemistry of Marine-Relevant Ice-Nucleating Particles with Gas-Phase Nitric Acid and Ozone

Heterogeneous ice nucleation is integral to the formation and optical properties of clouds as well as the global radiation budget, though this process is poorly constrained in climate models. In remote marine regions, sea spray aerosol (SSA) is an important source of ice nucleating particles (INPs). Following emission from the ocean, these INPs can be altered by interactions with trace reactive gases in the atmosphere. However, the effects of atmospheric aging on the immersion ice nucleation ability of marine INP is not fully understood. Here we investigate the impact of these reactions on SSA relevant INPs in situ using single particle Raman spectroscopy. Our results show a significant change in the Raman spectra following exposure to either ozone or nitric acid, but only a 1 to 3° decrease in immersion ice nucleating efficiency. This nominal suppression may indicate that though a reaction has occurred, active sites and particle nanoscale morphologies important for ice nucleation remain unchanged.