SmogRank / World / Europe / Switzerland
Most polluted cities in Switzerland
10 measured cities, this year; 9 above the WHO annual guideline. The most people breathing unhealthy air: Zürich, Switzerland, about 3.49K on an average day.
About 4.15K people in these 3 cities breathed unhealthy air on an average day so far this year.
Ranked by people: each city's population times its share of unhealthy days, those with a daily mean over 35.4 µg/m³ (US AQI 101+). That is how many people living there breathed unhealthy air on an average day. Only cities measured at 2 or more places at least 3 km apart are ranked: one monitor shouldn't speak for a whole city. Population is the city itself, not its wider metro area.
Now: cities by their PM2.5 over the last 24 hours; fires, smoke and ash from Oct 8, the newest day mapped.
Low-cost sensors: consumer units, counted only in cities with no government-grade monitor; they read close to reference monitors on the whole, but 15 to 25% high in humid air. How we use them.
The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales
Cleaner or dirtier than 2025
10 cities in Switzerland can be compared over 2026 so far (1 January to 8 October) with the same days of 2025: 4 got dirtier and 6 cleaner.
Biggest rises
- Lugano+1.8 µg/m³ (+23%)
- Giubiasco+1.4 µg/m³ (+14%)
- Bellinzona+1.4 µg/m³ (+14%)
- Küssnacht+0.2 µg/m³ (+4%)
Biggest falls
- Winterthur−5.9 µg/m³ (−40%)
- Payerne−0.9 µg/m³ (−11%)
- Basel−0.8 µg/m³ (−9%)
- Bern−0.5 µg/m³ (−5%)
- Kreuzlingen−0.2 µg/m³ (−2%)
Every city in Switzerland, and past years
Estimated: cities without a monitor
Switzerland cities we can't measure, with model estimates for the last 7 days. Listed by population, not ranked: estimates aren't precise enough to rank. Model estimates from the Copernicus Atmosphere Monitoring Service (CAMS), adjusted to measured cities nearby where there are any. Adjusted, a single day lands within ×1.5 of what a monitor would read about two times in three; unadjusted, it can be off by half or double. Treat them as a guide, not a measurement.
| City | 7-day estimate |
|---|---|
| Geneva | ≈ 9 µg/m³ |
| Lausanne | ≈ 7 µg/m³ |
| Luzern | ≈ 11 µg/m³ |
| Sankt Gallen | ≈ 7 µg/m³ |
| Biel/Bienne | ≈ 9 µg/m³ |
| Thun | ≈ 7 µg/m³ |
| Bellinzona | ≈ 13 µg/m³ |
| Köniz | ≈ 8 µg/m³ |
| Fribourg | ≈ 9 µg/m³ |
| La Chaux-de-Fonds | ≈ 7 µg/m³ |
| Schaffhausen | ≈ 8 µg/m³ |
| Chur | ≈ 4 µg/m³ |
| Rapperswil | ≈ 10 µg/m³ |
| Uster | ≈ 10 µg/m³ |
| Sitten | ≈ 5 µg/m³ |
| Neuchâtel | ≈ 10 µg/m³ |
| Emmen | ≈ 11 µg/m³ |
| Zug | ≈ 11 µg/m³ |
| Yverdon-les-Bains | ≈ 9 µg/m³ |
| Vernier | ≈ 9 µg/m³ |
| Montreux | ≈ 7 µg/m³ |
| Frauenfeld | ≈ 8 µg/m³ |
| Kriens | ≈ 11 µg/m³ |
| Wetzikon | ≈ 10 µg/m³ |
| Wil | ≈ 8 µg/m³ |
| Bulle | ≈ 8 µg/m³ |
| Horgen | ≈ 12 µg/m³ |
| Opfikon | ≈ 7 µg/m³ |
| Aarau | ≈ 13 µg/m³ |
| Renens | ≈ 10 µg/m³ |
| Dietikon | ≈ 8 µg/m³ |
| Baar | ≈ 11 µg/m³ |
| Bülach | ≈ 7 µg/m³ |
| Riehen | ≈ 10 µg/m³ |
| Vevey | ≈ 7 µg/m³ |
| Dübendorf | ≈ 9 µg/m³ |
| Meyrin | ≈ 9 µg/m³ |
| Carouge | ≈ 12 µg/m³ |
| Baden | ≈ 8 µg/m³ |
| Reinach | ≈ 10 µg/m³ |
Bad-air episodes in Switzerland
- Europe, 18 to 25 March 20268 days430 cities136 µg/m³peak, Łask
- Europe, 1 to 12 March 202612 days532 cities109 µg/m³peak, Radomsko
- Europe, January and February 202612 January to 12 February 2026, 32 days625 cities252 µg/m³peak, Travnik
- Eastern Europe, January 20269 to 10 January 2026, 2 days86 cities210 µg/m³peak, Bijelo Polje
- Europe, December 2025 to January 202625 December 2025 to 2 January 2026, 9 days189 cities110 µg/m³peak, Kempten (Allgäu)
- Eastern Europe, 16 to 21 December 20256 days129 cities298 µg/m³peak, Banja Luka
Times when many cities here had PM2.5 at twice their usual or more on the same days.
All 31 episodes in SwitzerlandUse this board
SmogRank, most polluted cities in Switzerland, by people breathing unhealthy air, PM2.5, this year to 10 Oct 2026, 03:00 UTC, smogrank.com/ch?w=year&by=people. Some readings from Uzhydromet (Uzbekistan's Hydrometeorological Service); Department of Environment, Nepal; Vietnam's government monitors; Aurassure; Umhverfisstofnun (Environment Agency of Iceland); Love My Air (City and County of Denver), no reuse terms published.
Download top 10 by average (PNG)
You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.
Regions
Measured cities in each region, this year.
Updated 2026-10-10 03:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index. Some readings: Uzhydromet (Uzbekistan's Hydrometeorological Service); Department of Environment, Nepal; Vietnam's government monitors; Aurassure; Umhverfisstofnun (Environment Agency of Iceland); Love My Air (City and County of Denver), no reuse terms published (why we use them).