SmogRank / The Netherlands / North Holland / Velsen-Zuid
Velsen-Zuid, month by month
Velsen-Zuid has a measured daily mean on 894 days since 1 January 2023. Its worst month was January 2026, at 68 US AQI (18.3 µg/m³), 546th of 2,617 cities on that month's world ranking. Its cleanest was July 2026, at 31 US AQI (5.5 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
16 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 | 14 of 31 days measured; a month needs 22. The others: 17 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 | 3 of 29 days measured; a month needs 21. The others: 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 | 7 of 31 days measured; a month needs 22. The others: 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. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Velsen-Zuid's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| January 2026 | 6818.3 µg/m³ | 546thof 2,617 | Europe, January and February 2026 |
| March 2025 | 6818.1 µg/m³ | 685thof 2,862 | Europe, March 2025 Germany, Poland and 25 more countries, March 2025and 1 more |
| February 2026 | 6416.3 µg/m³ | 719thof 2,866 | Europe, January and February 2026 |
| February 2023 | 6114.7 µg/m³ | 368thof 1,129 | Europe, 6 to 25 February 2023 |
| March 2026 | 6114.7 µg/m³ | 877thof 2,971 | Europe, 18 to 25 March 2026 Europe, 1 to 12 March 2026 |
| December 2024 | 5611.9 µg/m³ | 681stof 2,616 | – |
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.
Velsen-Zuid's worst days
| Day | US AQI | Episode |
|---|---|---|
| 25 Jan 2026 | 15560.5 µg/m³ | Europe, January and February 2026 |
| 5 Mar 2025 | 13248.2 µg/m³ | Germany, Poland and 25 more countries, March 2025 |
| 5 Feb 2026 | 12946.8 µg/m³ | Europe, January and February 2026 |
| 10 Feb 2025 | 12043.3 µg/m³ | Europe, 1 to 14 February 2025 |
| 15 Feb 2023 | 11942.8 µg/m³ | Europe, 6 to 25 February 2023 |
| 13 Feb 2025 | 11239.9 µg/m³ | Europe, 1 to 14 February 2025 |
| 24 Jan 2026 | 11139.6 µg/m³ | Europe, January and February 2026 |
| 14 Feb 2023 | 11139.4 µg/m³ | Europe, 6 to 25 February 2023 |
| 6 Feb 2026 | 10135.5 µg/m³ | Europe, January and February 2026 |
| 3 Feb 2026 | 10035.3 µg/m³ | Europe, January and February 2026 |
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, Velsen-Zuid, The Netherlands, 1 Jan 2023 – 11 Oct 2026. Monitor data from EEA, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/nl/velsen-zuid/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.
Velsen-Zuid 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).