SmogRank / The Netherlands / North Holland / Zaanstad
Zaanstad, month by month
Zaanstad has a measured daily mean on 843 days since 1 January 2023. Its worst month was January 2026, at 65 US AQI (16.7 µg/m³), 643rd of 2,617 cities on that month's world ranking. Its cleanest was October 2025, at 27 US AQI (4.8 µg/m³).
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
18 months
| Month | Why |
|---|---|
| Feb 2025 | 8 of 28 days measured; a month needs 20. The others: 20 with under 18 hours of readings or readings that failed our checks. |
| Jan 2025 | 6 of 31 days measured; a month needs 22. The others: 25 with under 18 hours of readings or readings that failed our checks. |
| Oct 2024 | 7 of 31 days measured; a month needs 22. The others: 24 with under 18 hours of readings or readings that failed our checks. |
| Sep 2024 | No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks. |
| Aug 2024 | 15 of 31 days measured; a month needs 22. The others: 16 with under 18 hours of readings or readings that failed our checks. |
| Mar 2024 | 11 of 31 days measured; a month needs 22. The others: 20 with under 18 hours of readings or readings that failed our checks. |
| Feb 2024 | 2 of 29 days measured; a month needs 21. The others: 1 missing from OpenAQ's archive, 26 with under 18 hours of readings or readings that failed our checks. |
| Jan 2024 | 3 of 31 days measured; a month needs 22. The others: 28 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 | 5 of 31 days measured; a month needs 22. The others: 26 with under 18 hours of readings or readings that failed our checks. |
| Jul 2023 | 6 of 31 days measured; a month needs 22. The others: 1 missing from OpenAQ's archive, 24 with under 18 hours of readings or readings that failed our checks. |
| Jun 2023 | 18 of 30 days measured; a month needs 21. The others: 12 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. |
| Mar 2023 | 12 of 31 days measured; a month needs 22. The others: 19 missing from OpenAQ's archive. |
| Feb 2023 | 3 of 28 days measured; a month needs 20. The others: 25 missing from OpenAQ's archive. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Zaanstad's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| January 2026 | 6516.7 µg/m³ | 643rdof 2,617 | Europe, January and February 2026 |
| March 2025 | 6215.2 µg/m³ | 934thof 2,862 | Europe, March 2025 Germany, Poland and 25 more countries, March 2025 |
| February 2026 | 6215.0 µg/m³ | 774thof 2,866 | Europe, January and February 2026 |
| March 2026 | 6114.3 µg/m³ | 909thof 2,971 | Europe, 18 to 25 March 2026 Europe, 1 to 12 March 2026 |
| January 2023 | 5410.8 µg/m³ | 415thof 1,261 | France, The Netherlands and United Kingdom, January 2023 |
| May 2024 | 5310.4 µg/m³ | 689thof 2,684 | – |
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.
Zaanstad's worst days
| Day | US AQI | Episode |
|---|---|---|
| 25 Jan 2026 | 15460.1 µg/m³ | Europe, January and February 2026 |
| 15 Feb 2023 | 13248.1 µg/m³ | Europe, 6 to 25 February 2023 |
| 5 Mar 2025 | 12645.7 µg/m³ | Germany, Poland and 25 more countries, March 2025 |
| 5 Feb 2026 | 12645.5 µg/m³ | Europe, January and February 2026 |
| 10 Feb 2025 | 11741.8 µg/m³ | Europe, 1 to 14 February 2025 |
| 13 Feb 2025 | 11340.5 µg/m³ | Europe, 1 to 14 February 2025 |
| 14 Feb 2023 | 11240.1 µg/m³ | Europe, 6 to 25 February 2023 |
| 24 Jan 2026 | 11039.0 µg/m³ | Europe, January and February 2026 |
| 10 Mar 2026 | 10537.3 µg/m³ | Europe, 1 to 12 March 2026 |
| 25 Jan 2023 | 9935.1 µg/m³ | France, The Netherlands and United Kingdom, January 2023 |
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, Zaanstad, The Netherlands, 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/nl/zaanstad/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.
Zaanstad now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 23:07 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).