SmogRank / World / Norway / Østfold / March 2025

Most polluted cities in Østfold, Norway, March 2025

3 cities in Østfold, Norway ranked by their average PM2.5 over the 31 days. Worst: Moss at 10.2 µg/m³, #1,548 of 2,809 cities in the world. Cleanest: Fredrikstad at 9.0. A city needs measurements on 70% of the days to be ranked.

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.

← Moss 3% 3%0
Every city in Østfold, Norway ranked for March 2025, 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. 1Moss
    3%
  2. 2Sarpsborg
    3%
  3. 3Fredrikstad
    3%
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, March 2025 · All cities in Norway, March 2025 · Østfold now

Use this board

SmogRank, most polluted cities in Østfold, Norway, PM2.5, March 2025, smogrank.com/no/region/ostfold/history/2025-03 (accessed 6 Oct 2026).

Download top 10 (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.