SmogRank / World / Europe / Finland / Uusimaa

Most polluted cities in Uusimaa, Finland

6 measured cities, last 30 days; 0 above the WHO 24-hour guideline. Worst: Helsinki at 4.7 µg/m³, #2,386 in the world.

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.

South Karelia: 1 measured cityKymenlaaksoUusimaa: 6 measured citiesSouthwest FinlandSatakunta: 1 measured cityPirkanmaa: 1 measured cityKanta-HämePaijat-Hame: 1 measured city#6 Hämeenkylä: 3.6 µg/m³#5 Kallahti: 4.0 µg/m³#4 Lohja: 4.2 µg/m³#3 Vantaa: 4.3 µg/m³#2 Laaksolahti: 4.6 µg/m³#1 Helsinki: 4.7 µg/m³
Each dot is a measured city, coloured by its PM2.5; tap a dot to open the city.
← Helsinki 0% 0.75%0
Every measured city in Uusimaa, Finland, 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. 1Helsinki 0%
  2. 2Laaksolahti 0%
  3. 3Vantaa 0%
  4. 4Lohja 0%
  5. 5Kallahti 0%
  6. 6Hämeenkylä 0%
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

Estimated: cities without a monitor

Uusimaa 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.

City7-day estimateBand
Espoo≈ 8 µg/m³Good
Porvoo≈ 7 µg/m³Good
Järvenpää≈ 8 µg/m³Good
Nurmijärvi≈ 8 µg/m³Good
Hyvinge≈ 7 µg/m³Good
Tuusula≈ 8 µg/m³Good
Kirkkonummi≈ 7 µg/m³Good
Kerava≈ 8 µg/m³Good
Vihti≈ 7 µg/m³Good
Raseborg≈ 6 µg/m³Good
Sibbo≈ 8 µg/m³Good
Klaukkala≈ 8 µg/m³Good
Mäntsälä≈ 7 µg/m³Good
Myyrmäki≈ 8 µg/m³Good

Bad-air episodes in Uusimaa

Times when many cities around here had PM2.5 at twice their usual or more on the same days.

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SmogRank, most polluted cities in Uusimaa, Finland, PM2.5, last 30 days to 6 Oct 2026, 22:00 UTC, smogrank.com/fi/region/uusimaa?w=30d.

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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.

Updated 2026-10-06 22:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index.