More than 100 million Europeans suffer from allergic rhinitis and 70 million from asthma, with the associated annual costs estimated at EUR 50-150 billion. Accurate pollen monitoring and forecasting is needed to prevent, diagnose and treat pollen allergy and to underpin the direction of R&D for new therapies. To support this, some of the leading European Meteorological Services launched the "EUMETNET Auto Pollen Programme", a self-funded collaboration between 11 EU countries, third parties from 9 additional European countries and two international groups. The goal of the EUMETNET programme is to establish an automatic pollen monitoring network in Europe for the real-time measurement of the number concentration of airborne pollen particles and the identification of their taxa. However, currently, neither calibration nor any quality assurance procedures exist to ensure measurement accuracy and reproducibility for automatic pollen monitors.
Currently, the counting of pollen particles and identification of their taxa relies on manual methods, i.e. collection of pollen on suitable substrates and subsequent inspection with a microscope. These methods provide poor time resolution, typically on a weekly basis, are time consuming and entail high personnel costs. In contrast, new automatic pollen monitoring instruments provide real-time measurements, are suited for unattended operation and will help to provide denser spatial coverage with lower running costs. However, the measurement accuracy and reproducibility of these instruments is not well known, since no reference aerosols or calibration methods currently exist for automatic pollen monitoring instruments.