Size of sea salt aerosols ranges widely from ~0.05 to 10 μm in diameter, with most of masses concentrated in super-micron range (coarse mode), and highest number concentration in sub-micron range. Correspondingly, sea salt aerosols have a wide range of atmospheric lifetimes. As the sea salt aerosols are hygroscopic, their particle sizes may vary with humidity by up to a factor of 2. Sea salt aerosols influence the sulfate aerosol formation in different ways due to the different sizes. Very small sea salt aerosols, which are below the critical diameter for droplet activation at low supersaturations, can serve as nuclei for the growth of sulfate particles, while larger sea salt particles serve as a sink for gaseous hydrogen sulfate (HSO) molecules, reducing the amount of sulfate available for the formation of accumulation mode particles.