Generally,mercury enriched substrate was considered an important atmospheric mercury source.In-situ total gaseous mercury(TGM)exchange fluxes between substrate surface and air were measured intensively at four sites from19to26December2003and two sites fro Generally, mercury enriched substrate was considered an important atmospheric mercury source. In-situ total gaseous mercury (TGM) exchange fluxes between substrate surface and air were measured intensively at four sites from 19 to 26 December 2003 and two sites fro