Chemistry of organic traces in air VI: Distribution of chlorinated C1 C4 hydrocarbons in air over the northern and southern Atlantic Ocean

Abstract Air-samples were collected on board of the German research vessel F.S. “POLARSTERN” on its cruise from Capetown to Bremerhaven (ANTARKTIS III/4, March 1985) by adsorption on Tenax TA. Additional samples were collected on the Azores ( 6 82 ), on Madeira ( 3 84 , 8 84 ) and on the Bermuda Islands ( 7 85 ). They were analyzed by high-resolution gas chromatography with electron-capture detection (HRGC-ECD). Tetrachloromethane (CCl4) is taken as a stable internal standard in tropospheric air for the characterization of anthropogenic organohalogen trace gases such as CHCl3, CH2ClCH2Cl, CH3CCl3, CHCl=CCl2, CCl2=CCl2 and minor constituents such as CH2ClCCl3, CHCl2CHCl2, CHCl2CCl3, CCl3CCl3 and CCl2=CClCCl=CCl2. Latitudinal distributions over the Atlantic Ocean and differences between distinct air masses with different origins are shown. With the concept of a normalized pattern analysis it is possible to characterize sources, transport and degradation processes on a global scale.