SmogRank / Velsen-Zuid / Zwanenburg
Velsen-Zuid vs Zwanenburg: PM2.5 compared
Over the last year, Velsen-Zuid's air was 8% more polluted than Zwanenburg's: PM2.5 averaged 10.0 µg/m³ against 9.3, on the 316 days both cities were measured. Velsen-Zuid had the dirtier air on 211 of those days, Zwanenburg on 93. Velsen-Zuid was over the WHO's daily guideline of 15 µg/m³ on 47 of them, Zwanenburg on 45.
Right now
The last year, day by day
Month by month
Year by year
| Year | Velsen-Zuid | Zwanenburg | Days Velsen-Zuid was worse |
|---|---|---|---|
| 2026 so far | 53 | 52 | 167 |
| 2025 | 51 | 47 | 183 |
| 2024 | 52 | 44 | 160 |
| 2023 | 43 | 44 | 21 |
Means in US AQI over the days both cities were measured that year; a year shows once they share 30 such days.
Each city's worst days
Velsen-Zuid
- 25 Jan 202615560.5 µg/m³
- 5 Feb 202612946.8 µg/m³
- 24 Jan 202611139.6 µg/m³
Zwanenburg
- 25 Jan 202615561.3 µg/m³
- 5 Feb 202613348.6 µg/m³
- 24 Jan 202610838.3 µg/m³
Daily means in US AQI, with µg/m³ beside them, since the index stops at its top value, over the days both cities were measured in the last year. Each date opens that day's world board.
Compare either city with another
Velsen-Zuid
Side by side with Breda (The Netherlands's worst on 30 days), Gujranwala (the world's worst on 30 days).
Zwanenburg
Side by side with Badhoevedorp (the nearest), Breda (The Netherlands's worst on 30 days), Gujranwala (the world's worst on 30 days).
Use this page
SmogRank, PM2.5 daily means compared, Velsen-Zuid and Zwanenburg, 10 Oct 2025 – 9 Oct 2026, smogrank.com/compare/nl-velsen-zuid/nl-zwanenburg (accessed 10 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.
The same rules as every SmogRank figure: reference monitors first, and a day counts with 18 measured hours. How we measure.
Updated 2026-10-10 10:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index. 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).