Aerosol – An aerosol is a suspension of fine solid particles or liquid droplets in a gas, which is usually air. Salt aerosol can be described as cloud of microscopic particles of salt in air. Beside sodium chloride ions (ions of Na+ and Cl−), other chemical ions which are common in natural rock salt, such as K+, Mg2+, Ca2+, SO42- and so on, can also be found in the salt aerosol.