Weekly Report

2 August 2024

City
Overall Risk
Tree Pollen
Grass Pollen
Weed Pollen
Mould Spores

Summary

The bitterly cold weather at most of these sampling sites has persisted, with frost at night and snow on high lying ground in some regions. Cypress is now seen at most of the sites as the trees begin their flowering cycle, but all the pollen concentrations remain low.

Cape Town

Very low temperatures and more rain kept pollen and mould concentrations low. Trees included cypress (Cupressaceae) and yellowwood (Podocarpaceae). No weed pollen was detected.:

Johannesburg

All pollen and mould concentrations remained low during this unusually cold midwinter period. Trees are starting their flowering season and included acacia (Acacia-type), Australian pine (Casuarina), the flamboyant tree (Delonix), beech (Fagus sylvatica), gum (Myrtaceae), olive (Oleaceae), karee (Rhus/ Searsia) and pine (Pinaceae). Weeds were slangbos (Stoebe-type).

Pretoria

4-year means are given. Trees usually seen in late July are: birch (Betulaceae), cypress (Cupressaceae), mulberry (Moraceae), yellowwood (Podocarpaceae), hackberry (Celtis), oak (Quercus), karee (Rhus/Searsia) and pine (Pinaceae). Weeds are slangbos (Stoebe-type), the carnation family (Caryophyllaceae), the daisy family (Asteraceae), heath (Ericaceae) and spurges (Euphorbiaceae). Moulds are generally low in concentration.

Bloemfontein

Pollen concentrations were low, but small increases in grass and trees are noted. Trees included the sumac family (Anacardiaceae), cypress (Cupressaceae), false olive (buddleia), mulberry (Moraceae) olive (Oleaceae) and karee (Rhus/Searsia). Weeds were the daisy family (Asteraceae), goosefoot (Chenopodiaceae) and mallows (Malvaceae). Mould concentrations were low.

Kimberley

Pollen and fungal spores were barely present at this sampling site, No rain fell, but nightly frost gave an indication of the low temperatures. Tree pollen was pecan (Carya) and weeds included only knotweed (Persicaria). Moulds were extremely low.

Durban

Pollen in all three categories was extremely low. Trees included cypress (Cupressaceae), bushwillow (Combretaceae) and gum (Mytaceae). No weed pollen was detected and mould was seen in low concentrations, despite small spikes for the allergenic mould, Cladosporium.

Gqeberha

Pollen and mould concentrations were extremely low in response to the cold, wet conditions. Tree pollen detected was mulberry (Moraceae) and weeds were the daisy family (Asteraceae).

Potchefstroom

This site is not operating.

George

Extremely low pollen and mould concentrations were seen during another week of cold and rain. Trees included cypress (Cupressaceae) and weeds were spurges (Euphorbiaceae). Moulds were found in low concentrations.

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