Weekly Report

12 April 2024

City
Overall Risk
Tree Pollen
Grass Pollen
Weed Pollen
Mould Spores

Summary

Tree, grass and weed concentrations were low throughout South Africa, except for moderate grass pollen in Gqeberha. Moulds were high in Potchefstroom, moderate in Durban and Gqeberha.

Cape Town

Grasses and weeds are generally low at this time of year. Trees are often moderate as birch (Betulaceae), pine (Pinaceae), olive (Oleaceae), forest elder (Nuxia), the sumac family (Anacardiaceae) and waxberry (Morella) pollen is present in the air. Weeds like knotweed (Persicaria), nettles (Urticaceae), erica (Ericaceae), the daisy family (Asteraceae), goosefoot (Chenopodiaceae), and plantain (Plantaginaceae) continue to flower. Moulds are invariably low. These are averaged concentrations.

Johannesburg: All tree, grass and weed pollen concentrations are low in this late autumn period. Moulds are similarly low. Tree pollen detected would be willow (Salicaceae), mulberry (Moraceae), cypress (Cupressaceae), pine (Pinaceae), bushwillow (Combretaceae), karee (Rhus/Searsia) and birch (Betulaceae). Weeds would be spurges (Euphorbiaceae) and slangbos (Stoebe-type). Moulds are usually low. Averaged counts.

Pretoria

Tree, grass and weed pollen is typically low at this site at this time of year. Trees are elm (Ulmaceae), Australian pine (Casuarina), cypress (Cupressaceae) and gum (Myrtaceae). Weeds are goosefoot (Chenopodiaceae), ferns (Polypodiaceae), goosefoot (Chenopodiaceae) and sunflower (Helianthus). Moulds are low. Averaged counts.

Bloemfontein

Pollen concentrations have waned. Small numbers of grasses and trees were detected. Tree pollen types included cypress (Cupressaceae), yellowwood (Podocarpaceae) and poplar (Populaceae). Weeds were mugwort (Artemisia), the daisy family (Asteraceae), sedges (Cyperaceae), erica (Ericaceae), plantain (Plantaginaceae) and sorrel (Rumex) Moulds were low with small, insignificant spikes for Cladosporium.

Kimberley

Pollen in all three categories was low at this site. Tree pollen included bushwillow (Combretaceae), mulberry (Moraceae) and birch (Betulaceae). Weeds were the daisy family (Asteraceae), the carnation family (Caryophyllaceae), Pellitory-of-the wall (Parietaria) and goosefoot (Chenopodiaceae). Moulds were generally low but with significant spikes for the allergenic spores Cladosporium and Alternaria.

Durban

Tree, weed and grass pollen concentrations were insignificant. Trees detected were cypress Cupressaceae), birch (Betulaceae) and gum (Myrtaceae). Weeds were ragweed (Ambrosia), mezereum (Thymelaeaceae), ferns (Polypodiaceae), plantain (Plantaginaceae) and the carnation family (Caryophyllaceae). Moulds were moderate with strong spikes for ascospores after rain.

Gqeberha

Grsses were moderate. Trees were low and included waxberry (Morella, linden (Tiliaceae) and marula (Sclerocarya). Low weed pollen concentrations included rush (Juncaceae), Evening primrose (Oenotheraceae), caltrops (Zygophyllaceae), sorrel (Rumex), mint (Lamiaceae) and ferns (Polypodiaceae). Maize (Zea mays) was seen in low concentrations. Moderate mould concentrations included small but consistent spikes for mushrooms (basidiospores) and the allergenic mould Cladosporium.

Potchefstroom

Pollen in all three categories was low at this site. No tree pollen at all was detected. Grasses were insignificant and the only weed identified was mugwort (Artemisia). Moulds were high and strong spikes were seen for the allergenic mould, Cladosporium.

George

Pollen concentrations for trees, grasses and weeds were low once again. Trees included false olive (Buddleja), Australian pine (Casuarina) bushwillow (Combretaceae), cypress (Cupressaceae), guarri (Euclea), karee (Rhus/Searsia), olive (Oleaceae) and a small spike for elm (Ulmaceae). Weeds were mugwort (Artemisia), the carnation family (Caryophyllaceae), sedges (Cyperaceae), erica (Ericaceae), pigweed (Amaranthaceae), plantain (Plantaginaceae), ferns (Poypodiaceae), slangbos (Stoebe-type) and bulrush (Typhaceae). Moulds were low.

Reference Range

Grass:      Low: 0-5       Moderate:      6-20         High: 21-200

Trees:      Low: 0-15     Moderate:    16-90         High: 91-1500

Weeds:   Low: 0-10      Moderate:   10-50         High: 51-500

Moulds:  Low: 0-900    Moderate:  900-2500   High 2500-25000

Unit: per cubic metre