Pollen information service
Continuous monitoring of airborne biological particles started in Turku, South-West Finland with Burkard pollen and spore traps in 1974. In 1976 sampling was expanded to Oulu and Kevo in Northern Finland and pollen information was started by weekly bulletins and pollen reports on national radio stations. At present air particle samples are continuously caught at nine Finnish locations.
In each of the sampling sites, a Burkard sampler runs throughout the pollen season. The air suction volume of the trap is ten litres per minute. Airborne particles are trapped on sticky tape attached onto a clockwork, which rotates itself at a rate of 2 mm per hour. Thus, the hourly particle content in the air can be calculated. The tapes are sent by post to Turku for the analysis. In the sampling sites of Helsinki (Skin and Allergy Hospital) and Imatra (Allergy and Environment Institute) the analysis is performed on the spot and mere results are sent to Turku for joint reporting. Pollen and spore reports are given on weekdays during the pollen season (usually from early March to September).
All pollen types are analysed from the tapes microscopically although only a fraction carries allergenic significance. Counting is done using random sampling method for burkard tapes (Mäkinen, 1981). Special threshold values are applied to various types of pollen. When constructing a pollen report, the counts are described on a verbal scale as sparse, moderate or abundant. Generally, a majority of allergic persons experience symptoms when the concentration is abundant, while low counts provoke symptoms only in the most sensitive persons. The pollen reports can be obtained from various sources in the mass media.
Detailed information on pollen and spore seasons are published in annual summaries,The Finnish Pollen Bulletin.