SmogRank / Poland / Mazovia / Ciechanów
Ciechanów, month by month
Ciechanów has a measured daily mean on 549 days since 7 January 2025. Its worst month was January 2026, at 110 US AQI (39.0 µg/m³), 90th of 2,617 cities on that month's world ranking. Its cleanest was July 2025, at 34 US AQI (6.2 µg/m³).
Every month since 2025
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
3 months
| Month | Why |
|---|---|
| Oct 2026 | 5 of 11 days measured; a month needs 8. The others: 2 with no readings from the monitor, 4 with readings for part of the day (a day needs 18 hours). |
| May 2026 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Apr 2026 | 12 of 30 days measured; a month needs 21. The others: 18 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.
Ciechanów's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| January 2026 | 11039.0 µg/m³ | 90thof 2,617 | Europe, January and February 2026 Poland, January 2026 |
| February 2025 | 9331.8 µg/m³ | 188thof 2,633 | Europe, 14 February to 1 March 2025 Europe, 1 to 14 February 2025 |
| March 2025 | 8125.0 µg/m³ | 433rdof 2,862 | Europe, March 2025 Germany, Poland and 25 more countries, March 2025and 1 more |
| February 2026 | 8125.0 µg/m³ | 375thof 2,866 | Europe, January and February 2026 |
| March 2026 | 7622.5 µg/m³ | 515thof 2,971 | Europe, 18 to 25 March 2026 Europe, 1 to 12 March 2026 |
| January 2025 | 6818.4 µg/m³ | 351stof 2,474 | Germany, France and 19 more countries, January 2025 |
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.
Ciechanów's worst days
| Day | US AQI | Episode |
|---|---|---|
| 20 Jan 2026 | 216141.0 µg/m³ | Europe, January and February 2026 |
| 21 Jan 2026 | 213138.0 µg/m³ | Europe, January and February 2026 |
| 24 Feb 2025 | 17690.8 µg/m³ | Europe, 14 February to 1 March 2025 |
| 6 Jan 2026 | 17183.8 µg/m³ | Poland, January 2026 |
| 26 Feb 2025 | 16474.3 µg/m³ | Europe, 14 February to 1 March 2025 |
| 23 Feb 2025 | 16068.9 µg/m³ | Europe, 14 February to 1 March 2025 |
| 8 Mar 2025 | 16067.8 µg/m³ | Germany, Poland and 25 more countries, March 2025 |
| 22 Jan 2026 | 15764.1 µg/m³ | Europe, January and February 2026 |
| 19 Jan 2026 | 15561.8 µg/m³ | Europe, January and February 2026 |
| 8 Mar 2026 | 15561.7 µg/m³ | Europe, 1 to 12 March 2026 |
Daily means, the highest since 7 Jan 2025; 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, Ciechanów, Poland, 7 Jan 2025 – 11 Oct 2026. Monitor data from EEA, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/pl/ciechanow/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.
Ciechanów now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 20:07 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).