SmogRank / Norway / Telemark / Porsgrunn
Porsgrunn, month by month
Porsgrunn has a measured daily mean on 980 days since 1 January 2023. Its worst month was January 2024, at 75 US AQI (21.9 µg/m³), 228th of 2,385 cities on that month's world ranking. Its cleanest was July 2024, at 31 US AQI (5.5 µg/m³). 2025 averaged 50 US AQI (9.0 µg/m³), against 51 US AQI (9.2 µg/m³) in 2024.
Every month since 2023
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
Months without a mean, and why
15 months
| Month | Why |
|---|---|
| Oct 2026 | 6 of 12 days measured; a month needs 9. The others: 6 with readings for part of the day (a day needs 18 hours). |
| Sep 2026 | No day measured. The others: 30 with readings for part of the day (a day needs 18 hours). |
| Aug 2026 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Jul 2026 | 2 of 31 days measured; a month needs 22. The others: 29 with under 18 hours of readings or readings that failed our checks. |
| Dec 2025 | 19 of 31 days measured; a month needs 22. The others: 12 with under 18 hours of readings or readings that failed our checks. |
| Nov 2025 | No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks. |
| Oct 2025 | 9 of 31 days measured; a month needs 22. The others: 22 with under 18 hours of readings or readings that failed our checks. |
| Dec 2023 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Nov 2023 | No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks. |
| Oct 2023 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Sep 2023 | 4 of 30 days measured; a month needs 21. The others: 26 with under 18 hours of readings or readings that failed our checks. |
| Aug 2023 | 4 of 31 days measured; a month needs 22. The others: 27 with under 18 hours of readings or readings that failed our checks. |
| Jul 2023 | 5 of 31 days measured; a month needs 22. The others: 26 with under 18 hours of readings or readings that failed our checks. |
| Jun 2023 | 11 of 30 days measured; a month needs 21. The others: 19 with under 18 hours of readings or readings that failed our checks. |
| May 2023 | 17 of 31 days measured; a month needs 22. The others: 14 with under 18 hours of readings or readings that failed our checks. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Porsgrunn's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| January 2024 | 7521.9 µg/m³ | 228thof 2,385 | Southern Norway, 18 to 20 January 2024 Southern Norway, 12 to 13 January 2024and 1 more |
| January 2025 | 6215.1 µg/m³ | 483rdof 2,474 | Southern Norway, 4 January 2025 |
| March 2026 | 6014.0 µg/m³ | 947thof 2,971 | Europe, 1 to 12 March 2026 |
| December 2024 | 5812.6 µg/m³ | 621stof 2,616 | – |
| February 2025 | 5712.3 µg/m³ | 997thof 2,633 | – |
| February 2023 | 5712.2 µg/m³ | 529thof 1,129 | Europe, 6 to 25 February 2023 |
Monthly means over the days measured; finished months only. World rank: its place on that month's world ranking of every city with enough days. Each month opens that ranking.
Porsgrunn's worst days
| Day | US AQI | Episode |
|---|---|---|
| 19 Jan 2024 | 15460.3 µg/m³ | Southern Norway, 18 to 20 January 2024 |
| 20 Jan 2024 | 12746.2 µg/m³ | Southern Norway, 18 to 20 January 2024 |
| 31 Dec 2025 | 12746.2 µg/m³ | – |
| 1 Jan 2026 | 12645.5 µg/m³ | – |
| 9 Jan 2024 | 11742.2 µg/m³ | Southern Norway, 5 to 10 January 2024 |
| 7 Jan 2024 | 11641.4 µg/m³ | Southern Norway, 5 to 10 January 2024 |
| 6 Jan 2024 | 10637.7 µg/m³ | Southern Norway, 5 to 10 January 2024 |
| 8 Jan 2024 | 10436.7 µg/m³ | Southern Norway, 5 to 10 January 2024 |
| 11 Jan 2026 | 9834.4 µg/m³ | – |
| 13 Jan 2024 | 9633.3 µg/m³ | Southern Norway, 12 to 13 January 2024 |
Daily means, the highest since 1 Jan 2023; the WHO's daily guideline is 15 µg/m³. Each date opens that day's world ranking, and each episode the bad-air spell it was part of.
Use this history
SmogRank, PM2.5 monthly and daily means, Porsgrunn, Norway, 1 Jan 2023 – 12 Oct 2026. Monitor data from EEA, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/no/porsgrunn/history (accessed 12 Oct 2026).
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.
Porsgrunn now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 22:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index. Some low-cost readings: Sensor.Community, ODbL (data and licence). Some readings: Uzhydromet (Uzbekistan's Hydrometeorological Service); Department of Environment, Nepal; Vietnam's government monitors; Aurassure; Umhverfisstofnun (Environment Agency of Iceland); RMCAB (Secretaría Distrital de Ambiente, Bogotá); Love My Air (City and County of Denver), no reuse terms published (why we use them).