According to the pollen bulletin, released by the Portuguese Society of Allergology and Clinical Immunology (SPAIC), in the Azores and Madeira archipelagos, forecasts point to low concentrations.

Forecasts until May 30 indicate high levels of pollen in the air in Vila-Real (Trás-Os-Montes and Alto Douro region), Porto (Entre Douro and Minho), Coimbra (Beira Litoral), Castelo Branco (Beira Interior), Lisbon (Lisbon and Setúbal), Évora (Alentejo) and Faro (Algarve).

Pollen grains from olive, pine, birch, chestnut, cork oak, oak trees, grassy herbs, and nettles will predominate in the atmosphere.

When pollen concentrations are high, SPAIC recommends avoiding outdoor activities and advises keeping car windows closed whenever traveling, to reduce contact with pollen. Motorcyclists must wear a full-face helmet.

The pollen bulletin publishes every week the levels of pollen in the atmosphere, collected through readings from stations in various regions of the country.