Application of backward air mass trajectory analysis in evaluating airborne pollen dispersion

To investigate airborne pollen movement aerobiologists use backward air mass trajectories. In the present paper the peculiarities of airborne birch pollen dispersion are analysed. In 2005 at Šiauliai Aerobiology Station pollen was recorded using Hirst-type spore trap. The situation of birch bloom in neighbouring European countries was evaluated according to the European Aeroallergen Network database. It was generalized and used to prove long-range pollen transport. Air mass trajectories were calculated according to the HYSPLIT 4 model the trajectory drawing principle of which is based on the integration of the position of air mass with regard to time. The present study has shown that backward air mass trajectory analysis may be applied in investigating relationship among pollen dispersion, meteorological conditions and air mass transport. It is estimated that at Šiauliai Aerobiology Station the dynamics of pollen concentration is determinated by local flora and airborne pollen long-range transport. The evaluation of pollen dispersion by the backward air mass trajectory method presented in the paper established precondition to look for possibilities of application of the HYSPLIT 4 model to prepare the forecasts of pollen dispersion.