- D3.516 - Airborne pollen where and when it should not exist – Towards ‘allergy-safe’ environments or adopting a Planetary Health approach?

Allergic diseases have been characterized as an environmental disease and one of the pandemics of the century. Moreover, ongoing climate change has been threatening biodiversity and creating new and emerging aeroallergens that may pose even direr allergy risks in the future. In contrast to urban environments, certain locations like islands, start being considered as ‘allergy-safe’ sites. In certain, remote, environments, like islands and mountains, where vegetation is isolated and/or scarce, one consequently anticipates lower aeroallergen exposure, which implies lower risk for manifestation of allergic symptoms. 

This study is among the first attempt to investigate airborne pollen biodiversity and abundance in an island ecosystem. Sampling was conducted in Paliochori (307 m elevation), Lesvos island, Northeastern Aegean, Greece, during the peak of the tourist season, from 1^st-29^th August 2024. Two Hirst-type portable pollen-traps (Burkard Manufacturing Co. Ltd.), positioned in opposite directions, north and south, operated for 20 min twice per day, at 10 a.m. and 10 p.m. Taxonomic identification and counting of pollen grains were performed using an optical microscope. The concentrations of each taxon were expressed as pollen m^-3 of air and compared with main meteorological parameters, whereas pollen origin was investigated using HYSPLIT Backward Trajectory models. 

A total of 21 pollen taxa were identified, seven of which showed higher abundance (>4% of the total). Biodiversity remained stable, trending higher in abundance during nighttime hours, mainly from the northeastern and southeastern directions. Pollen season peaked in the third part of August. Conclusively for the study period, biodiversity and abundance of airborne pollen in Lesvos  originated not only from outside of  island ecosystem, but even outside Greece. This finding aligned with existing information on airborne pollen measurements in neighbouring countries and prevalent wind circulation patterns.

Because of the complexity of environmental parameters and along with the ongoing climate change, it is less likely that one may find ‘allergy-safe’ locations. However, by adopting a Planetary Health approach, and by assessing the multi-exposure taking into account ecological and biomedical indicators, timely information and holistic knowledge is expected to contribute to optimal allergy prophylaxis.