Air quality in Portugal: where to check and what to do

Short answer. Check QualAr, the air quality information system of the Portuguese Environment Agency (APA), on the web or in the QualAr mobile app ²⁴. Its index rates air in five colour-coded classes, from "Muito Bom" (very good) to "Mau" (bad), using the worst-rated pollutant ¹. QualAr also gives a forecast for today and tomorrow, and the app shows a warning with health advice when poor air is forecast ³.

Where can I check air quality right now?

On QualAr ⁴. Monitoring stations run by the regional coordination and development commissions (CCDR) on the mainland, and by the regional environment directorates in the Azores and Madeira, send their data to QualAr in near real time ². The same information is available in the QualAr mobile app ²³.

QualAr also publishes a forecast for the current day and the next day for the whole country, developed by the University of Aveiro and supplemented when needed by the EU's Copernicus Atmosphere Monitoring Service (CAMS) ³.

What do the index levels mean?

The QualAr index is calculated daily from station measurements and shows the worst classification obtained, on a colour scale of five classes from "Muito Bom" to "Mau" ¹. In zones it must include ozone and PM10 or PM2.5; in urban agglomerations, nitrogen dioxide and PM10 or PM2.5; sulphur dioxide is added where measured ¹. The APA notes that the index describes short-term air quality, not the long-term (annual) situation ¹. When poor air is forecast, the QualAr app shows a warning together with health advice ³. See Air quality index explained.

How polluted is the air on average?

Moderately. The population-weighted median of Portuguese cities shows about 9 µg/m³ of PM2.5 (annual mean 2021-2023) ⁵, almost twice the WHO guideline of 5 µg/m³ ⁷. Nitrogen dioxide is about 8.2 µg/m³ ⁶, under the WHO guideline of 10 µg/m³ ⁷. That NO2 figure is a regional background over roughly 80 km: a busy street will be higher.

What should I do on a bad air day, or with smoke or dust?

• Pollution alerts: Portugal sets an information threshold for ozone and alert thresholds for nitrogen dioxide, sulphur dioxide and ozone ². When they are exceeded, the information goes to local authorities, health authorities and the public, notably through national, regional and local media, and appears in QualAr and its app ². See Pollution episodes and Ozone days.
• Sensitive people: the APA's stated aim for the index and the forecast is to let people, especially the most sensitive, reduce their exposure ¹³. See Sensitive people and polluted air and Children and polluted air.
• Wildfire smoke: see Wildfire smoke, A clean-air room at home and Masks for smoke. Our Portugal alerts page explains how civil protection warnings reach you.
• Dust: see Dust storms.

A household plan can list who in your home is sensitive to polluted air and where to shelter.

Frequently asked questions

What is Portugal's official air quality index?

The QualAr index of the APA, with five classes from "Muito Bom" to "Mau" ¹.

Is there an air quality forecast in Portugal?

Yes. QualAr and its app give a forecast for today and tomorrow across the country ³.

How will I hear about an ozone or pollution alert?

Through the media, QualAr and the QualAr app; local and health authorities are also informed ².

Does the index show long-term pollution?

No. The APA says it reflects short-term air quality, not the annual situation ¹.

Sources

1. Agência Portuguesa do Ambiente (APA) — Índices de qualidade do ar — https://apambiente.pt/ar-e-ruido/indices-de-qualidade-do-ar (accessed 2026-10-27)
2. Agência Portuguesa do Ambiente (APA) — Acesso da população à informação — https://apambiente.pt/ar-e-ruido/acesso-da-populacao-informacao (accessed 2026-10-27)
3. Agência Portuguesa do Ambiente (APA) — Previsão da qualidade do ar — https://apambiente.pt/ar-e-ruido/previsao-da-qualidade-do-ar (accessed 2026-10-27)
4. Agência Portuguesa do Ambiente (APA) — QualAr – Base de dados on-line sobre qualidade do ar — https://qualar.apambiente.pt/ (accessed 2026-10-27)
5. Atmospheric Composition Analysis Group (ACAG), Washington University in St. Louis — Surface PM2.5, V6.GL.02.04 (annual mean 2021-2023) — https://sites.wustl.edu/acag/datasets/surface-pm2-5/ (accessed 2026-10-27)
6. Copernicus Atmosphere Monitoring Service (CAMS) — CAMS global reanalysis (EAC4) — https://ads.atmosphere.copernicus.eu/ (accessed 2026-10-27)
7. World Health Organization (WHO) — WHO global air quality guidelines (2021) — https://www.who.int/publications/i/item/9789240034228 (accessed 2026-10-27)