Forecast

Grasses, fungal spores and the first mugwort of the season are tickling our noses!

Monday will bring bright sunshine and midsummer temperatures of up to 33 degrees to Vorarlberg, with only a few harmless cumulus clouds forming over the peaks. On Tuesday, it will become increasingly muggy and changeable – showers and thunderstorms will spread across the whole region. Wednesday will remain very warm, with the likelihood of thunderstorms continuing to rise as the day progresses. The unsettled weather will continue on Thursday too: sunshine and cumulus clouds will alternate, and with maximum temperatures between 26 and 31 degrees, we can still expect some heavy thunderstorms.

Grasses – moderate to high levels throughout the country: Grasses remain the main allergen in the ambient air. In valley areas and lowlands – such as the Rhine Valley, the Walgau and the shores of Lake Constance – grass pollen levels have stabilised at a moderate level. This is due to the end of the flowering season for early-flowering grasses, as well as mowing. Locally, however – particularly along streams or in deciduous forests – grass pollen levels may still remain high. The current hotspots for pollen levels are alpine pastures and mountain meadows – in the Bregenzerwald, the Montafon and the Arlberg, the diversity of native grasses is particularly noticeable. Above around 1,000 metres, the grasses continue to flower vigorously and release pollen. Under certain wind conditions – particularly with evening downdrafts from the mountains – grass pollen from higher altitudes can be carried into the Rhine Valley and the lowlands, causing additional pollen levels there. Sorrel and plantain are also still in flower and contribute to pollen levels.

Mugwort – the herb pollen season begins: In Vorarlberg, too, mugwort (Artemisia vulgaris) is beginning to flower. Mugwort pollen levels in the region are usually only low to moderate, but allergy sufferers should not underestimate the start of the flowering season. Mugwort prefers to grow in ruderal habitats – on rubble sites, along railway embankments, at the sides of roads, on wasteland and other fallow areas. Particularly affected are the ruderal areas along the Rhine and the Ill, the railway lines through the Rhine Valley and the Walgau, the industrial and commercial estates around Dornbirn, Feldkirch and Bregenz, and the wasteland on the outskirts of built-up areas. Mugwort pollen is highly allergenic – even concentrations of 10 to 20 pollen grains per cubic metre of air can trigger significant symptoms in sensitised individuals. Cross-reactions with celery, carrots, chamomile and other composite flowers are common and must be taken into account.

Maize – exposure only near fields: Maize has begun to flower in its growing regions. Maize pollen grains are among the largest in the plant kingdom. Due to its size and comparatively high weight, it is only carried over short distances. Elevated pollen concentrations are therefore to be expected primarily in the immediate vicinity of flowering maize fields.

Fungal spores – levels rising: People with allergies who are sensitised to fungal spores should expect moderate to high levels in the coming days. Elevated concentrations of fungal spores occur particularly around fields where harvesting is currently taking place. Threshing grain stirs up large quantities of fine dust and fungal spores. Sporal concentrations also rise significantly following rainfall and thunderstorms – such as those forecast for Tuesday, Wednesday and Thursday – with Cladosporium and Alternaria in particular releasing increased amounts of spores at such times. Relief can be found by spending time at higher altitudes, as fungal spore levels decrease significantly with increasing altitude.

In addition to the pollen types already mentioned, pollen from umbellifers, spirea shrubs, pines, nettles, amaranths and junipers is currently also present in the pollen spectrum. However, these pose only a very low allergenic risk.

Recommendations for allergy sufferers: Given the summer heat and the moderate to high pollen levels, it is recommended that outdoor sport and physical activities be scheduled for the early morning or late evening – experience shows that pollen concentrations are at their lowest at these times. People with a grass pollen allergy should be aware of the higher pollen levels in the mountains when hiking in the Bregenzerwald, Montafon or the Arlberg. Those allergic to mugwort should take particular care in ruderal areas: railway embankments, rubble sites, roadsides and riverbanks along the Rhine and the Ill should be avoided. Wearing sunglasses, rinsing your hair in the evening and changing your clothes after spending time outdoors can help to reduce pollen exposure.

Warning regarding ozone and thunderstorm asthma: Given the forecast heat, concentrations of ground-level ozone may rise, causing further irritation to the airways. As thunderstorms approach – as forecast for Tuesday, Wednesday and Thursday – pollen, particularly that from grasses and mugwort, is torn apart by strong downdrafts (downbursts) and fragmented into extremely fine particles small enough to enter the lungs, which can penetrate deep into the airways. This can lead to sudden, severe asthma attacks in people with pollen allergies – even those who have not previously had asthma. People with a known history of asthma or hay fever are strongly advised to seek shelter indoors when thunderstorms are approaching and to keep their emergency medication to hand.