How does salinity influence submicron aerosol production?

When bubbles are created by breaking ocean waves, they burst and create a shower of droplets which contribute to sea spray aerosols. Submicron-sized droplets in the atmosphere play a key role in cloud properties and formation, which subsequently affects the climate. However, many aspects of predicting the number and size of submicron drops emitted from a bursting bubble remain unclear. It has been documented that submicron droplet production increases with salinity, which has been attributed to bubble coalescence inhibition. We experimentally show that submicron drop production increases with salinity even when using a salt that does not affect bubble coalescence. Additionally, the peak droplet formation diameter decreases with higher salinity, consistent with a changing bubble cap film thickness. This size shift suggests that bubble coalescence is not the only mechanism by which salinity affects submicron droplet production. As a result, salinity likely impacts the submicron aerosol production flux near melting glaciers or other environments with large salinity variations, even if bubble coalescence is negligible.