Chemical exchange at the air coastal sea interface plays an important role in coastal biogeochemical cycles.Atmospheric deposition (dry plus wet)can be a significant process for chemical entering coastal waters.Mass balance estimates suggest that in some coastal regions,the atmospheric input of certain trace elements can be similar to or greater than that from rivers.Atmospheric deposition can be a significant non point source for nitrogen entering coastal systems,which could be an important mechanism responsible for coastal eutrophication.Currently estimates of atmospheric deposition rates have considerable uncertainty.Improvements in these estimates require the developments of methods for the direct measurements of both dry and wet fluxes.