AIRBORNE BIRCH POLLEN ANTIGENS IN DIFFERENT PARTICLE SIZES

Two particle samplers for ambient air, situated together: a Static siz e-selective bioaerosol sampler (SSBAS) and a Burkard pollen and spore trap were compared in sampling intact birch pollen grains through one flowering period of Betula (a total of 44 days). The SSBAS trapped pol len grains three times more efficiently than the Burkard trap, but the variations in pollen counts were significantly correlated. In contras t, birch pollen antigenic activity and the pollen count in the Burkard samples were not closely correlated. The antigenic concentration was occasionally high both before and after the pollination period. There was a high birch pollen antigenic activity in particle size classes wh ere intact pollen grains were absent, even on days when the pollen cou nt was very low. Correspondingly, on days with high birch pollen count s in the air, pollen antigenic activity was on several occasions low, indicating that pollen grains were empty of antigenic material. The sm all particle size classes are especially important to allergic patient s because they are able to penetrate immediately into the alveoli and provoke asthmatic reactions. Therefore, aerobiological information sys tems based on pollen and spore counts should be supplemented with info rmation concerning antigenic activities in the air.