Airborne Pollen Concentrations in Leiden, The Netherlands, 1977–1981

Abstract

Results of five years of continuous monitoring of airborne pollen concentrations with a volumetric trap in Leiden indicate that almost 36% of the total pollen count originates from a group of 23 taxa, herbs and weeds flowering in the summer, between May and October. More than 95 % of the airborne summer-weed pollen are from Urtica, Rumex, Artemisia, Plantago, and Chenopodiaceae, Urtica predominating with over 85%. Of the three most frequent summer-weed pollen types, both Rumex and Urtica show variable seasonal patterns, whereas Artemisia is more constant. Although large concentrations of Urtica pollen are often found, allergic sensitization is infrequent. The converse is true of Artemisia pollen, which could be a cause of pollinosis in August in spite of the relatively low concentrations in the air.