Apparatus and methods for detecting the presence of an airborne chemical or biological analyte utilise:a substantially gas- and liquid-impermeable container; means for introducing a substantially analyte-free collection liquid into said container; means for rapidly sampling ambient air and transferring said analyte therefrom into said collection liquid, said sampling means comprising an air intake means and and an air venting means; and-means for removing from said container an analyte-enriched collection liquid; wherein said volume of air passes through a substantially horizontal air inlet and upwardly through a substantially vertical collector electrode tube with means for applying an electric field between said tube and a co-axial spiked wire- or rod-shaped discharge electrode.