For the week between April 19th and 25th, despite the high concentrations across Portugal, in the central and Alentejo regions there will be rain and showers over the weekend, temporarily lowering the concentration of pollen in the air, due to the effect of “atmospheric washing”.

According to the SPAIC Pollen Bulletin, after the precipitation stops, the concentration of pollen in the atmosphere of these regions will rise again, adds SPAIC.

Currently, and in general, the atmosphere in Portugal features pollen grains coming from cypress, pine, oak, holm oak, and cork oak trees and grassy herbs, plantain, nettle, sorrel, and nettles (including parietaria).

In the regions of Beira Litoral, Algarve, Lisbon and Setúbal, the first grains of pollen from the olive tree are beginning to be detected in the air, and in the Algarve, Lisbon and Setúbal, the pollination of the chenopodium stands out.

In the northern and central regions of the country, birch pollination is being observed, which will continue.

In the autonomous regions of the Azores and Madeira, where concentrations will be low during the week in question, the pollens present in the atmosphere are predominantly from pine and cypress (and/or cryptomeria in the Azores) and from urticaceous herbs (including parietaria), plantain and grasses.