AIRSPORA OF JOHANNESBURG AND PRETORIA, SOUTH-AFRICA, 1987 88 .2. METEOROLOGICAL RELATIONSHIPS

The possibility of forecasting the occurrence of seasonal allergens was investigated, using multiple stepwise regression analysis. Airspora data were collected with Burkard traps during 1987 and 1988. Grass pollen and fungal spores in the cities of Johannesburg and Pretoria were considered. Meteorological factors used were maximum and minimum temperatures, rainfall, relative humidity, sunhours, radiation, windspeed and pressure. In Johannesburg rain and sunhours were of primary importance for grass pollen, while windspeed at 14h00 and minimum temperature were the most significant parameters in Pretoria. For fungal spores, pressure and windspeed at 20h00 were most important in Johannesburg, with rain being the primary factor in Pretoria. This marked variability is probably attributable to climatic differences between the two cities. Although they are situated only seventy kilometres apart, Johannesburg lies within the grasslands of the Bankenveld, and Pretoria borders on the warmer savanna of the Bushveld.