Abstract
Adsorption sampling on Tenax GC combined with thermal desorption and cold trap injection allowed the analysis of 2-500 l of air as a single sample. The separation by high resolution gas chromatography and electron capture detection revealed a complex pattern of baseline pollution of C1-C4 organohalogens in clean continental and marine air. Air samples from the Azores and from the Madeira Archipelago, above and below the trade-wind inversion, gave similar patterns of pollution.