Levels of Ambrosia pollen in the atmospheric spectra of Catalan aerobiological stations.

Ambrosia pollen is known as an importantallergen in North America, and more recently in someEuropean countries. From 1989 to 1995, the Ambrosia pollen levels detected at the stationsmonitored by the Aerobiological Network of Catalonia(Xarxa Aerobiològica de Catalunya, XAC) wereinsignificant. In 1996, a considerable althoughtemporary increase in the concentration of this pollenwas detected in the atmosphere over Girona, Barcelona,Bellaterra, Manresa, and Tarragona. Most of the Ambrosia pollen collected in 1996 was concentrated ina single day. Its appearance on that day wasattributed to long range transportation, caused byunusual conditions of atmospheric circulation, fromthe Lyon region in France where the species isabundant. This is the only day where concentrations of Ambrosia pollen that may be dangerous to humanhealth have been reached. Ambrosia coronopifolia is the most abundantspecies of the genus in Catalonia, and although rare,its expansion is favoured by the fact that it growsthrough rhizomes and sprouts easily. It is, therefore,important to monitor the growth of its population andthe release of its pollen in order to predict theappearance of pollen levels that may precipitateallergic symptoms. [ABSTRACT FROM AUTHOR]