MeteoSwiss operates the national pollen monitoring network. This consists of 14 monitoring stations which cover Switzerland's most important climatic and vegetation regions. Additional monitoring stations are operated in order to monitor levels of ragweed pollen. The measurements recorded by the respective pollen traps provide valuable information for those who suffer from allergies.
Pollen monitoring network
The airborne concentrations of 48 different pollen types are measured at each of the 14 monitoring stations. In order to monitor levels of ragweed pollen more precisely, MeteoSwiss operates additional stations in Ticino as well as near Geneva, where high concentrations of ragweed pollen are sometimes registered.
During the pollen season, the pollen data recorded at each measuring station is made available on the Wednesday of the following week
How a volumetric pollen trap works (Hirst design)
Each monitoring station has a volumetric pollen trap (Hirst type). With the help of a pump, this pollen trap sucks in ten litres of air per minute through a 14 x 2 mm opening. Behind this entry slot is a rotating drum on which there is a silicon-coated plastic strip. The pollen and other organic and inorganic particles sucked in with the air stick to this strip. The drum is changed once a week and then sent to the analysis centre in Payerne where daily specimens are prepared using the strip. The types of pollen are identified and counted under a microscope and concentrations per cubic meter air are calculated. Apart from pollen, other organic particles, such as fungal spores, are also found on the specimen slide, as well as various inorganic particles, such as sand from the Sahara Desert or specks of soot.
Automatic measurement of pollen dispersal
In order to deliver real-time pollen data, MeteoSwiss has tested various options and demonstrated the feasibility of automatic pollen monitoring. The system is based on laser scattering and induced fluorescence (Crouzy et al. Atmospheric Environment, 2016). Here, particles in the air are stimulated by laser beams and the pollen grains and other types of particles are identified on the basis of their specific characteristics. MeteoSwiss is preparing the future of pollen monitoring.