To quantify airborne allergens in amorphus and morphological particles, a survey with collection of aero-allergens on glass fibre filters by means of a high-volume air-sampler (HIVOL) was conducted. In preliminary laboratory experiments we compared various filter elution techniques, and the pulverizing elution technique was found to be optimal with regard to yield and convenience. When a surfactant, Tween 20 (0.5% v/v), was added to the elution buffer, a recovery of 80% could be obtained. Allergens in eluates were analysed by means of an IgG-subclass RAST inhibition assay. This immunochemical method for quantification of airborne allergens was validated, as a high recovery of timothy grass pollen allergens was eluted from air filters, and eluates were shown specific by RAST inhibition. The amount of immunochemically measured airborne timothy and birch allergens collected by means of the HIVOL sampler was highly correlated with pollen counts obtained with a Burkard sampler (pollen trap) situated in the same place.