Trends in land cover and in pollen concentration of Quercus genus in Alentejo, Portugal: Effects of climate change and health impacts.

Mediterranean forests dominated by Quercus species are of great ecological and economic value. The Quercus pollen season, peaking in April, varies in concentration due to geographical and climatic factors and has a remarkable allergenic potential. This study investigates Quercus trends in the Alentejo region of Portugal and examines the influence of meteorological parameters on DPC, PSD and SPIn, as well as the impact on allergic respiratory disease. The results show a progressive increase in Quercus Forest area from 1995 to 2018. Temperature and Precipitation are a key factor influencing pollen concentration, especially before peak of pollen season and prior to the pollen season. Particularly prior to the season, the precipitation of t-6 before influence, significantly, the pollen production. On the other hand, Global Srad and RH determine the beginning of the season. Using quartile-based categorization and multivariate statistical analysis, we identified years and scenarios within the IPCC projections where meteorological conditions influence may SPIn production. The study found a statistically significant correlation between high Quercus pollen concentrations in April and increased antihistamine sales. These findings are crucial for enhancing pollen forecast models and early warning systems.