Frequent rain during the recent sampling period removed pollen and fungal spores from the air. On sunny days following rain, ascospores, basidiospores and Cladosporium concentrations increased. The weed, Parietaria is flowering and moderate concentrations were seen on sunny days.
The autumn weather has set in with intermittent rain, longer nights and some clear, calm days. Pollen concentrations in the categories of trees, grasses and are all low, but some low concentrations for grasses and weeds such as Myrica were seen. Fungal spores are moderate as basidiospore (mushroom) appear in the atmosphere in response to the cooler temperatures and increased humidity.
Fungal spore concentrations increased in response to a little rain and cooler temperatures with early morning dew. Cladosporium increased but no significant concentrations were recorded. Alternaria levels were moderate. Weed levels are increasing as we move into autumn and Myricaceae concentrations are increasing. Tree and grass pollen concentrations were low.
Pollen and fungal spore concentrations reverted to their earlier low levels as no rain fell during the sampling period ending 12 March. After the rain that occurred yesterday in some areas of Cape Town, fungal spore levels are expected to increase, especially Alternaria, Cladosporium and ascospores.
The recent rain increased fungal spore production. Alternaria and Cladosporium levels increased sharply to allergenic levels. Tree and grass pollen levels are low, but week pollen is increasing.
The rain during this sampling week affected the bioaerosols by sharply increasing the concentrations of fungal spores and pollen in the atmosphere. Significant Alternaria concentrations were seen and Epicoccum, Rusts ascospores and Cladopsorium concentrations increased. Moderate concentrations were consistently seen for Chenopod, or goosefoot weed.
Fungal spore levels will probably remain high following yesterday’s thunderstorm. Weed pollen will increase as autumn approaches.
The drought conditions have resulted in very dry air with low pollen and fungal spore concentrations. In some areas of Cape Town, light rain has fallen at times and there has been an immediate response in the Alternaria and Cladosporium concentrations. Cladosporium spores are scant, despite increases but Alternaria is a dry air spore and spores quickly after rain. The Alternaria concentrations at the Observatory sampling site this week were just below the significant level.
Extremely low levels of pollen and fungal spores were seen during the recent sampling period. Low levels for trees, grasses and weeds were present in the atmosphere. The fungal spore levels are usually low in January, but the drought has further depressed the concentrations.
The tree, grass and weed pollen concentrations were all low during the past sampling week. Rain at the end of the preceding sampling week impacted on the fungal spores and moderate levels of Alternaria were seen. The fungal spore load was generally low.
Pollen concentrations in the tree, grass and weed categories have been consistently low. Fungal spore levels have been generally low but increased after rain on Sunday 7 January. Cladosporium and Alternaria levels increased and while these concentrations did not breach the significant threshold, the small peaks should be noted.