Acid mist, commonly referring to a mist of acidic substances. The particles of acid mist in the air are very small, smaller than those of water mist, and more humid than smoke, being a substance between smoke and water mist, with strong corrosive properties. They mainly originate from sulfur oxides and nitrogen oxides emitted from the combustion of fossil fuels, as well as some from vehicle exhausts (mainly nitrogen oxides). Methods to control the emissions of acid mist include liquid absorption, solid adsorption, filtration, electrostatic dehumidification, mechanical dehumidification, and covering, among others.