The present work analyses the airborne pollen dynamic of the atmosphere
of Toledo (central Spain), a World Heritage Site and an important tourist city receiving
over 2 millions of visitors every year. The airborne pollen spectrum, the annual dynamics
of the most important taxa, the infl uence of meteorological variables and the risk of
suffering pollen allergy are analysed. Results of the present work are compared to those
obtained by similar studies in nearby regions. The average annual Pollen Index is 44,632
grains, where 70–90% is recorded during February–May. The pollen calendar includes 29
pollen types, in order of importance; Cupressaceae (23.3% of the total amount of pollen
grains), Quercus (21.2%), and Poaceae and Olea (11.5 and 11.2%, respectively), are the
main pollen producer taxa. From an allergological viewpoint, Toledo is a high-risk locality
for the residents and tourist who visit the area, with a great number of days exceeding
the allergy thresholds proposed by the Spanish Aerobiological Network (REA). The
types triggering most allergic processes in Toledo citizens and tourists are Cupressaceae,
Platanus, Olea, Poaceae, Urticaceae and Chenopodiaceae-Amaranthaceae. Allergic risk
increases in 3 main periods: winter (January–March), with the main presence of the Cupressaceae
type; spring, characterized by Poaceae, Olea, Platanus and Urticaceae pollen
types; and, fi nally, late summer (August–September), characterized by Chenopodiaceae-
Amaranthaceae pollen type, which are the main cause of allergies during these months
