Towards operational processing centre of the European AutoPollen network for automatic bioaerosol monitoring

Bioaerosols interact with society and environment in a multi-faceted way. Information about biological aerosols in the atmosphere is at high demand for medical practitioners and allergy sufferers, climate change researchers, agriculture and forestry industries, air quality forecasters, a variety of information added-value businesses, and many other stakeholders. However, the monitoring practices established over 70 years ago and barely changed since then are country-specific, with varying data availability and usage policy. These roadblocks slow down cross-disciplinary research and development of measures to understand and, upon necessity, control societal and environmental impacts of bioaerosols.

A series of technological breakthroughs during last 10 years introduced a variety of automatic particle counters capable of bioaerosol monitoring in real time. They paved the way to the volunteering consolidation of European aerobiologists to establish the EUMETNET AutoPollen Programme (www.autopollen.net), laid down the foundation for the bioaerosol monitoring infrastructure with the EU Horizon SYLVA project (A SYstem for reaL-time obserVation of Aeroallergens, https://sylva.bioaerosol.eu), initiated developments of European standards and guidelines for the automatic bioaerosol measurements with the EURAMET project BioAirMet, and started the European standardization effort with CEN WG 39.

The new technologies allow to observe bioaerosol concentration in real time, analyze vertical concentration profiles via remote-sensing, perform metagenomic analysis of bioaerosols with the 3^rd generation DNA sequencing technique, and combine these observations with atmospheric composition models. Newly established regional networks have been connected to regional atmospheric composition models, which assimilate the real-time regional data to improve the forecasts. It changes the existing paradigm of bioaerosol observations as the new monitoring networks involve large-scale data handling infrastructure, which also includes numerical models as an interface between the different technologies and a bridge to users of information.

The new observations heavily rely on sophisticated technologies, such as high-resolution image analysis, holography, multi-band scatterometry and fluorescence spectrometry, lidar-based remote sensing, and nanotechnology for DNA sequencing. A particle recognition task, the key challenge for the new devices, is solved via machine learning approaches. Technological complexity of the new instruments and large amounts of raw data they produce have been recognized, and a European-scale solution has been proposed by AutoPollen/SYLVA. AutoPollen is being converted into a EUMETNET operational programme with the SYLVA infrastructure as its technological backbone. The programme, with support of Copernicus Atmosphere Monitoring Service (https://atmosphere.copernicus.eu), ACTRIS aerosol monitoring network, and other stakeholders, will become operational from 2027. The central processing system will be hosted by Finnish Meteorological Institute with support of MeteoSwiss, Technical University of Munich, and all SYLVA partners. The pre-operational work of AutoPollen/SYLVA started already in 2025, owing to the efforts of the SYLVA consortium, its sister projects and collaborators. The programme is open for all European (and from outside Europe) groups performing automatic bioaerosol monitoring. AutoPollen offers technological and organizational support, community-developed bioaerosol monitoring solutions, and a motivated team of experts advancing the relevant research and applications.