Concentration distributions of volatile organic sulfur compounds and their sources in the seawater and overlying atmosphere of the East China Sea in September 2017
Volatile organic sulfur compounds (VSCs) are main participants of the sulfur cycle and play significant roles in global climate change and atmospheric chemistry.The concentrations of three main VSCs including carbonyl sulfide (COS),dimethyl sulfide (DMS) and carbon disulfide (CS_2) in the seawater and overlying atmosphere of the & East China Sea were determined by Purge and Trap-Gas Chromatography during September 2017.Moreover,the sea-to-air fluxes of VSCs were also calculated in the study period.The average concentrations of COS,DMS and CS_2 in the surface water of the East China Sea were (0.14 0.08)、(3.58 2.81) and(0.06 0.06) nmol·L~(-1),respectively.The average concentrations of COS,DMS and CS_2 in the atmosphere over the East China Sea were (414.9107.4) *10~(-12),(39.729.9) *10~(-12),(92.955.6) *10~(-12),respectively,and COS was the most abundant VSC in the atmosphere.The correlation analysis showed that there was a correlation between the DMS and CS_2 concentrations in the seawater,which might be due to their similarity in source pathways.Besides,a significant correlation was found between the COS and CS_2 concentrations in the atmosphere,revealing that CS_2 is the main source of COS.In addition,all concentrations of COS,DMS,and CS_2 in seawater were supersaturated,and their average sea-to-air fluxes were (0.450.58)、(13.1512.66) and(0.20 0.22) mumol·m~(-2)·d~(-1),respectively,indicating that the East China Sea acted as an essential source for atmospheric VSCs in the study period.