SPAIC Lifts a Continental Pollen Alert From Friday Through 7 May — Cypress, Pine, Oak, Birch and Olive on the Tree List, Grasses and Plantain on the Weed List, and Seven Regions Inside the High-Concentration Window

The Sociedade Portuguesa de Alergologia e Imunologia Clínica — the medical society that runs Portugal's only daily pollen-monitoring network through the Rede Portuguesa de Aerobiologia — placed mainland Portugal under a high atmospheric-pollen advisory on Thursday afternoon, valid from Friday, 1 May through Thursday, 7 May 2026. The alert covers seven of the country's eight continental aerobiological regions and identifies the particular tree and weed species expected to drive symptoms over the bank-holiday weekend and the working week that follows.

The Tree List Is Long This Year

The species responsible for the highest counts in the network's daily traps are cypress, pine, birch, oak, cork-oak and holm-oak. The Mediterranean trio — pine, cork-oak (sobreiro) and holm-oak (azinheira) — produce vast quantities of pollen but tend to provoke milder reactions than the central-European species. Birch, by contrast, is a strong allergen and the prime cross-reactor with apple, peach, hazelnut and a host of stoned fruits in patients with oral allergy syndrome. Cypress is the species clinicians watch most carefully in late spring because counts can stay elevated for weeks at a time and because the pollen is small enough to penetrate deep into the respiratory tract.

The Weed List Drives the Day-to-Day Symptoms

On the weed side, SPAIC's network is calling out grasses (gramíneas) — the dominant Atlantic-Iberian weed allergen and the textbook trigger for hay-fever-style rhinoconjunctivitis and asthma — alongside plantain (tanchagem), sorrel (azeda), nettle, and Urticaceae more broadly. Grass-pollen counts typically peak between mid-May and mid-June in Portugal; this week's alert reflects an early-season climb on the back of the warm, dry conditions IPMA has forecast for the long weekend.

Which Regions Are Inside the Alert

Seven aerobiological regions are flagged: Trás-os-Montes e Alto Douro, Entre Douro e Minho, Beira Litoral, Beira Interior, Lisboa e Setúbal, Alentejo and Algarve. The Madeira archipelago and the Azores fall outside the SPAIC continental network and operate on a separate monitoring schedule.

What to Do

• If you have a diagnosed pollen allergy, SPAIC's protocol is to start daily preventive medication — second-generation oral antihistamines, intranasal corticosteroids, or both — at the first day of the alert, not after symptoms appear. The pharmacological window for getting ahead of grass-pollen exposure closes within 48 hours.
• If you have asthma, your maintenance inhaler should be in regular use through the alert window. Carry the rescue inhaler. Atmospheric thunderstorms — IPMA is forecasting some for Saturday — can rupture pollen grains into smaller respirable fragments and trigger so-called thunderstorm-asthma episodes.
• For unmanaged or new symptoms — itchy eyes, persistent sneezing, dry cough — the SNS pathway runs through your família-doctor first; the immunoallergology referral is the route to confirmatory skin-prick testing, RAST blood work, and the specific-immunotherapy programme that is the only disease-modifying treatment available.
• Practical mitigation: keep car windows closed in the morning and on windy afternoons; avoid hanging laundry outdoors during the alert; rinse hair before bed; and, for runners and cyclists, shift training to the early morning before counts climb.
• Foreign residents from temperate-climate countries often discover Portugal-specific pollen sensitivities — particularly to olive (oliveira) and cork-oak — that did not exist in their home environment. If your spring symptoms began after moving to Portugal, the diagnostic panel should include the Mediterranean species, which northern-European clinics rarely test for.