Seasonal and diurnal variation of pollen from Gramineae in the atmosphere of Córdoba Spain.

We have carried out a study on the annual and diurnal variation of pollen from the Gramineae family in the atmosphere of Córdoba (Southern Spain) during three consecutive years. This family, according to its high sensitizing capacity and to data from allergologists, is responsible for most of the pollenoses diagnosed in the city. Pollen grains from Gramineae were found to occur in the atmosphere virtually throughout the year, starting in February. Yet, they reach their highest levels in spring, particularly in May and the first fortnight of June. Such levels decrease gradually during the summer and become virtually imperceptible from October. The concentration of pollen grains from Gramineae were found to be positively correlated with the average temperature, and negatively correlated with the average humidity. The diurnal variation pattern of the concentration of pollen grains from this family was rather homogeneous throughout the three years studied, with a marked increase early in the morning, a moderate decrease in the afternoon and stable values throughout the night.