Fog

Fog is a visible aerosol consisting of tiny water droplets or ice crystals held in the air near the Earth's surface. Fog can be considered a type of low-lying cloud usually resembling stratus and is heavily influenced by nearby bodies of water, topography, and wind conditions. In turn, fog affects many human activities, such as shipping, travel, and warfare. Recent atmospheric research indicates that fog also functions as an active aquatic ecosystem. Fog droplets harbor microbiomes where bacteria actively grow, divide, and interact with atmospheric chemistry. Fog appears when water vapor (water in its gaseous form) condenses. During condensation, molecules of water vapor combine to make tiny water droplets that hang in the air. Sea fog, which shows up near bodies of saline water, is formed as water vapor condenses on bits of salt. Fog is similar to, but less transparent than, mist.