The pollen present in the air on the continent comes essentially from cypress and pine trees, but also from cork oaks, olive holm oaks, and even herbs.

Forecasts until April 18 indicate a high level of pollen concentration 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).

The forecast for the Azores and Madeira archipelagos indicates, in both, a week with low concentrations.

The pollen bulletin reveals weekly pollen levels in the atmosphere, collected through reading stations in various regions of the country.