A Comparative Analysis of Daily Variations in the Gramineae Pollen Counts at Córdoba, Spain and London, UK

Abstract

Abstract The features of five grass pollen seasons from two areas of contrasting climate were investigated and the relative importance of the variables controlling daily variations were determined. The records from London, UK (temperate maritime climate) and Córdoba, Spain (mediterranean climate) were analysed in relation to meteorological factors. The length of the seasons differs a great deal between the two locations and from year to year. However the total cumulative catches and the number of days with counts over 50 grains metre-3 are similar for the two locations. Regression analysis of standardised daily average pollen counts shows clearly that for London, maximum and average temperatures are the most important factors influencing daily variation. In the case of Córdoba this relationship holds true for the period from the start of the season until the peak count, but after this the relationship becomes negative. Hours of sunshine and humidity are also important. The negative effect of increased humidity on pollen release is most marked in the data for Córdoba but it is also apparent in the case of London. The results emphasise the need for individual analysis in different climates and the application of different statistical treatments depending on the operation of the variables.