Aerobiological study of Chenopodiaceae and Amaranthaceae in the Mediterranean area of southwestern Spain

The study area is characterized by a maritime Mediterranean climate abundan t presence of Chenopodiaceae in the vegetation and a high incidence of poll inosis caused by the pollen of this family A Hirst-type sampler was used to determine pollen concentrations in the air of the city of Huelva during 3 consecutive years (1995-1997). The total annual amount of Chenopodiaceae-Am aranthaceae pollen was between 10.59% and 6.28% of the pollen spectrum of t he city depending on the year. The annual pattern of variation in pollen co ncentration (5-day means) was very similar in the 3 years, and no statistic ally significant differences were found between years. This pattern is char acterized by concentrations not exceeding 20 grains/m(3) between April and the beginning of August, with an obvious seasonal variation in the second h alf of August and September when the 5-day mean concentrations exceeded 40 grains/m(3) and the daily maxima exceeded 100 grains/m(3). This coincided w ith the flowering of most of the species in the group. The meteorological p arameters with a statistically significant effect on daily pollen concentra tion during the pollen season (August 15 to September 20) included mean tem perature and south wind (positive correlations) and relative humidity of th e air (negative correlation). The highest intradiurnal concentrations were found between 10:00 a.m. and 5:00 p.m.