A 6 dm 3 cryogenic trap has been constructed from PTFE and stainless steel to allow the quantitative sampling of large volumes of air for gaseous alkyllead species. Air volumes up to 50 m 3 can be sampled by this method, giving detection limits in the range 1–10 pg (Pb) m −3 for the various gaseous alkyllead species. Collection and recovery efficiencies are better than 95% and analysis is carried out by gas chromatography-atomic absorption spectrophotometry (GC-AAS). The equipment has been used at coastal sites in NW Scotland and SW Eire and air concentrations in the range 0.17–1.65 ng m −3 of total alkyllead found, representing 3–16% of the total lead present. The significance of these data in elucidating the role of alkyllead in the global biogeochemical cycle of the metal is discussed.