The effectiveness of a nine-minute personal Burkard trap in comparison to a seven-day continuous Burkard trap for pollen and spore sampling

Abstract

This study compares the nine-minute Personal Burkard in relation to the seven-day Continuous Burkard for the sampling of airborne pollen and fungal taxa in the Maltese islands. Both devices were positioned adjacent on the roof of the Chemistry & Pharmacology Building at the University of Malta Campus for a total of four sampling sessions, each lasting one week between March and July 2025. The Personal Burkard operated for nine minutes only for three days of the sampling week. While the Continuous Burkard operated for the whole week (7 days) but only three of those sampling days were considered. The collected samples were analysed microscopically, converting the particles in absolute and relative values of grains per cubic metre (grains/m3 ) following the European Aeroallergen Network (EAN) procedure (European Standard CEN168:2019). Due to the different capture durations, the Continuous Burkard captured a greater number of pollen grains (1,824) and spores (19,405) in relation to the Personal Burkard (99 pollen grains and 2,002 spores). However, the Personal Burkard recorded higher relative concentrations (grains/m3 .min) and more pronounced shortterm peaks. For both devices, the top pollen taxa Arecaceae, Casuarina-type, Cupressaceae, Fabaceae and Poaceae were similar, while Cercospora sp. was the only common spore. The Continuous Burkard recorded diurnal data and early seasonal pollen occurrences, whereas the Personal Burkard was more sensitive to sudden high peaks and late-season taxa. Wind analysis indicated predominant north and northwest influences, corresponding to the direction of the nearby Wied Għollieqa valley and surrounding landscaped areas, which were possible influential contributions to the sampled taxa. This study finds that the devices complement each other: the Continuous Burkard provides representative long-term sampling, while the Personal Burkard effectively captures peak events and provides a snapshot of the current aerobiological taxa as present during sampling. This is the first comparative aerobiological assessment of these devices in the Maltese islands and offers a foundational dataset for future studies on allergen forecasting, climate change and regional vegetation phenology. Further works are recommended to include long-term sampling periods; analysis of meteorological factor influences and spatial analyses.