title: Urticaceae pollen concentration in the atmosphere of North Western Spain.
abstract: Plants of the Urticaceae family can develop into a pest on soils enriched with nitrogen. Urticaceae pollen is a biohazard because it elicits severe pollinosis. Pollen grains were sampled by using a Lanzoni seven-day-recording trap from February 1995-December 2000 in the atmosphere of the city of Ponferrada (Leon, North Western Spain). The Spearman test was used to analyse the statistical correlation between Urticaceae pollen and certain meteorological factors in different main pollination periods. Maximum values are reached in June and July, minimum levels are recorded in January and December. The parameters bearing the greatest positive influence on the occurrence of Urticaceae pollen grains are: temperature (maximum, minimum and mean), humidity (absolute, wet-bulb temperature, dew point and mixing ratio) and south western wind direction; negative parameters are: relative humidity, rainfall and period without wind. The highest correlation coefficients were obtained with temperature and wet-bulb. Absolute humidity and wet-bulb temperature yielded better correlation than relative humidity; hence, these two parameters must be included in this type of study. The use of one main pollination period or another in statistical analysis has an influence on the coefficient value. The behaviour of the pollen grains in the atmosphere during the year also influences the results.
authors.affiliation: Departamento de Biologia Vegetal (Botanica), Facultad de Ciencias Biologicas y Ambientales, Universidad de Leon. Campus de Vegazana, 24071 Leon, Spain. dbvavm@unileon.es
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: Vega-Maray
authors.forename: Rosa
authors.initials: R
authors.lastname: Valencia-Barrera
authors.forename: Delia
authors.initials: D
authors.lastname: Fernandez-Gonzalez
authors.forename: Roberto
authors.initials: R
authors.lastname: Fraile
mesh_terms: D000393:Air Pollutants / Q000009:adverse effects* / Q000032:analysis; D006801:Humans; D011058:Pollen / Q000009:adverse effects*; D012130:Respiratory Hypersensitivity / Q000453:epidemiology* / Q000209:etiology*; D012621:Seasons; D013030:Spain / Q000453:epidemiology; D027003:Urticaceae / Q000009:adverse effects*
chemical_list: D000393:Air Pollutants