Daily and seasonal variations ofAlternaria andCladosporium airborne spores in León (North-West, Spain)

The spores ofAlternaria andCladosporium are present throughout the year in the atmosphere of León (NW Spain), although they show an important seasonal variation. To understand the relationship between the number of spores and climatic factors,Alternaria andCladosporium spores counts for January 1994 to December 1995 were examined by means of correlation analyses. The results of weekly samples of both years showed that the spores concentration of two taxa are significantly and positively correlated with maximum and minimum temperature and sunshine hours and negatively with relative humidity. The statistical analysis of daily samples generally showed the same results. In the hourly distribution of spore concentrations we can see a similar behaviour ofAlternaria andCladosporium, with most spores collected in the 12–14 h period.