SmogRank / World / Switzerland / 2023

Most unhealthy days in Switzerland, 2023

7 cities in Switzerland ranked by their share of unhealthy days over the 365 days. The most unhealthy days: Basel, Switzerland, 1 of 334 measured days. A city needs measurements on 70% of the days to be ranked.

OpenAQ's archive, where our readings come from, has almost none for 56 of these 365 days. Cities in the United States and Europe have them from the EPA's and the European Environment Agency's own records of the same monitors; elsewhere a city's average is over its other days. Why.

Ranked by unhealthy days: the share of each city's measured days with a daily mean over 35.4 µg/m³ (US AQI 101+), Unhealthy for Sensitive Groups or worse on the US EPA's scale. Ties go to the higher average.

← Basel 0% 0.75%0
Every city in Switzerland ranked for 2023, one column each, ranked by unhealthy days: height is the share of its measured days that were unhealthy, colour its average. Point at it to read a city; tap to open it.
  1. 1BaselBasel-City
    1 of 334
  2. 2GiubiascoTicino
    0 of 276
  3. 3LuganoTicino
    0 of 276
  4. 3Bernlow-cost sensorsBern
    0 of 274
  5. 5ZürichZurich
    0 of 276
  6. 6PayerneVaud
    0 of 276
  7. 7KüssnachtSchwyz
    0 of 275

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.

Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

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

All cities in the world, 2023 · Switzerland now

Regions

Basel-City 1Bern 1Schwyz 1Ticino 2Vaud 1Zurich 1

Ranked cities in each region, 2023.

Use this board

SmogRank, most polluted cities in Switzerland, by unhealthy days, PM2.5, 2023, smogrank.com/ch/history/2023?by=days (accessed 10 Oct 2026). 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.