Incidence of atmospheric pollen in the Pretoria-Witwatersrand-Vereeniging region during 1987/1988.
Atmospheric pollen and spores have been monitored continuously in the Pretoria-Witwatersrand-Vereeniging region (PWV) since 1987. Two Burkard 7-day recording traps were used in Johannesburg and Pretoria, and 11 gravity samplers were installed at various sites in the PWV. An analysis of the pollen component and pollen calendars average data for 1987 and 1988 are presented. Grass pollen was the most significant contributor in absolute and relative terms, comprising 52% of total pollen. The season peaked between October and March, but grass pollen was found throughout the year. Pollen of Northern Hemisphere trees was abundant, relative to that of indigenous trees. The flowering season for these exotics was very short and intense, possibly due to the short spring season. Seasonal taxa started flowering earlier in Pretoria than in Johannesburg. Herbaceous taxa were well represented in the atmospheric sample. The major contributor was the daisy family. The greatest proportion of pollen, 58.8%, was non-seasonal. Species in this category flower consecutively throughout the year. Of the taxa, 28.4% were spring-flowering. The allergenicity of pollen encountered in the atmospheric sample is discussed.
Cadman
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Department of Botany, University of the Witwatersrand, Johannesburg.
D000393:Air Pollutants / Q000032:analysis*; D011058:Pollen / Q000032:analysis*; D012621:Seasons; D013019:South Africa
D000393:Air Pollutants