Hay fever: How does the pollen prediction work?
Sneezing attacks, runny nose, itchy eyes and swollen eyelids are clear signs for allergy sufferers: the pollen fly again. Every year, millions of Germans suffering from hay fever are plagued by the small particles of pollen that circulate around them. A helpful service for those affected is the pollen forecast. It informs, which pollen are currently on the way. But how does the prognosis actually come about?
So that hay fever sufferers know when they have to equip themselves again with allergy agents, informs the German Weather Service (DWD) regularly about the current pollen count. In cooperation with the German Pollen Information Service (PID), the so-called pollen hazard index is being developed for this purpose. This indicates the concentration of the eight most important allergenic pollen in Germany: hazel, alder, ash, birch, grasses, rye, mugwort and ambrosia.
Bloomers under observation
Of course, the forecast should be as accurate as possible. That's why the experts use many different sources and data. These include, among others, people who observe the plants in nature. For them is of particular interest, which plants bloom. Only what flourishes, can finally send pollen in the air.
Around 400 such plant observers are on the road in this country for the DWD. They report immediately when they notice the flowering of hazel, birch & co in their region. Your observations will then be included in the daily pollen forecast.
Traps for pollen
Even more precise information is provided by special pollen traps, which are used today in almost all European countries during the pollen season. In the Federal Republic, such measuring instruments operate the PID. They are in about 45 places. Your simple task: collect pollen.
The pollen traps continuously suck in a defined amount of air through a slot using an electric motor? always from the direction the wind is coming from. The aspirated volume corresponds approximately to the amount of air that an adult would breathe in at rest during the same time. In the case, the air is then passed past a slowly rotating drum, at the top of which a sticky plastic strip is attached. If pollen particles are present in the air, they will adhere to it.
Species determination under the microscope
At the latest after seven days, the pollen traps must be evaluated - a tedious job: Under a microscope, employees count how many pollen have remained stuck to the strip. And they decide what kind of species it is. Because all pollen species have certain characteristic structures, they can be easily distinguished.
Based on these results, experts calculate a 24-hour average of pollen per cubic meter of air for relevant pollen species. This value is forwarded to the weather services. As a rule, in the traps at the beginning of the year, more hazel and alder pollen land, followed by the birch in the spring. In summer, grasses and cereals are added. The ambrosia plants imported from North America extend the pollen season into late summer and autumn.
Influence factor weather
But how many pollen fly depends not only on the flowering behavior of the individual plants. The current weather conditions also play a role. For example, downpours can provide relief because they at least partially wash the pollen out of the air. Therefore, the regional short- and medium-term weather forecasts serve as a further basis for the pollen forecast.
Allergy sufferers can view the result of these complex calculations at any time on the Internet at www.dwd.de/pollenflug or via the app of the DWD. In general, however, the data are also published in daily newspapers and on radio and television.
Are "your" pollen present again? Then you should get medication quickly. In order to keep allergic colds at bay, symptoms should ideally always be treated early enough? otherwise there is a risk that the symptoms become chronic and spread to the bronchi.
