SmogRank / History / City race
Cities in Portugal, worst air first, day by day
Each measured city's average over the 30 days to every day since January 2023, worst first. Find your own city to follow it through the race, or keep to one country.
The worst cities in Portugal for PM2.5 over the 30 days to 11 Oct 2025: Porto 16.5 µg/m³, Ponte de Lima 7.3 µg/m³ and Santiago do Cacém 4.6 µg/m³.
- 1PortoPorto16.5
- 2Ponte de LimaViana do Castelo7.3
- 3Santiago do CacémSetúbal4.6
- 4FunchalMadeira4.3
- 5SinesSetúbal3.0
- 6SantanaMadeira2.9
- 7FaroFaro2.9
Not counted on this day, too few days measured: Paredes since 29 Sep 2025 and Freamunde since 29 Sep 2025.
Cities counted each day
A city's number is its average over the 30 days, shown only when 21 of them were measured (5 of 7 on the 7-day race), the same minimum as the 30- and 7-day boards. A city whose monitors go quiet fades out where it stood rather than sliding down, so a gap never reads as cleaner air. Some large countries are thin or missing because their monitors' licences don't allow reuse. How we rank.
Not covered: the government monitoring networks of China and Turkey, which publish only on their own websites; we are building the readers for them. Most cities there are missing from this board, not clean. Why.