Edited sentence: ) removes acids from the atmosphere and delivers it to the Earth's surface.Acid deposition also occurs via dry deposition in the absence of precipitation.For more information see Seinfeld and Pandis (1998).HSO3-  H+ + SO32−.SO2 (g) + H2O  SO2·H2O.SO2·H2O  H+ + HSO3−.Sulfur dioxide dissolves in water and then, like carbon dioxide, hydrolyses in a series of equilibrium reactions:.The most important oxidation reactions are with ozone, hydrogen peroxide and oxygen (reactions with oxygen are catalyzed by iron and manganese in the cloud droplets).There are a large number of aqueous reactions that oxidize sulfur from S(IV) to S(VI), leading to the formation of sulfuric acid.This can be responsible for as much as 20 to 60% of total acid deposition.This can result from the deposition of acids produced in the raindrops (see aqueous phase chemistry above) or by the precipitation removing the acids either in clouds or below clouds.This is due to reactions in the liquid water droplets.This occurs when particles and gases stick to the ground, plants or other surfaces.Wet deposition of acids occurs when any form of precipitation (rain, snow, etc.Wet removal of both gases and aerosols are both of importance for wet deposition.When clouds are present, the loss rate of SO2 is faster than can be explained by gas phase chemistry alone