engleski

Impact of atmospheric and local regional flow regimes on the maximum ragweed pollen concentrations in Zagreb, Croatia

Ragweed pollen is extremely allergenic that causes many health problems such as rhinitis, rhinoconjunctivitis and bronchial asthma. In this study, we used the back-trajectories together with measured meteorological data to examine the maximum ragweed pollen concentrations. We selected two periods of research with the maximum concentrations that occurred in the first week of September 2002 and 2003. Daily ragweed pollen concentrations during considered days exceeded 600 grains/m3 of air. The mesoscale WRF numerical model experiments showed successful multi-day simulations in Zagreb reproducing (i) the local topography influence on local wind flow, (ii) the formation of an urban heat island over the city and (iii) reasonable coincidence with the available observations. Hourly back-trajectories indicated the most probable reasons for the high nightly two-hour concentration peaks recorded in Zagreb. The long-range transport was significantly supplemented by the horizontal recirculation of pollen grains within diurnal local thermal circulation over the city, causing the higher late evening concentration increase.

transport of pollen grains; slope winds; urban heat island circulation; recirculation of pollen grains; WRF model

nije evidentirano