Intradiurnal variations of allergenic tree pollen in the atmosphere of Toledo (central Spain).

To study the impact of inhaling airborne pollen on health, it is important to know not only their average daily concentrations but also the intradiurnal behaviour of these biological particles. This study reports the bi-hourly distribution of the arboreal airborne pollen types more abundant in the atmosphere of Toledo (central Spain), many of them triggering important allergic processes in Toledo citizens and tourist visitors. Knowledge of bi-hourly pattern atmospheric variation pollen may help pollinosis patients to adopt preventive measures and plan their outdoor activities accordingly. Intradiurnal variation has been studied for the arboreal pollen types: Cupressaceae, Fraxinus, Olea, Platanus, Populus, Quercus and Ulmus, during the period 2005-2008. The main hourly pollen concentrations were observed during sunlight hours and the maximum pollen values obtained at midday and in the afternoon, except for pollen types Quercus and Platanus, whose maximum pollen concentrations were obtained during the night. The statistical analyses performed to compare pollen concentration and main hourly meteorological variables proved to be significant for most of the taxa. The results show a significant and positive effect of temperature, solar radiation and wind speed on the daily variability undergone by atmospheric pollen. Relative humidity influenced in a negative way on the intradiurnal variation of pollen in the atmosphere of Toledo.

Pollen spectrum and risk of pollen allergy in central Spain.

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 influence 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 percent is recorded during February-May. The pollen calendar includes 29 pollen types, in order of importance; Cupressaceae (23.3 percent of the total amount of pollen grains), Quercus (21.2 percent), and Poaceae and Olea (11.5 and 11.2 percent, 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, finally, late summer (August-September), characterized by Chenopodiaceae- Amaranthaceae pollen type, which are the main cause of allergies during these months.