SmogRank / World / Europe / The Netherlands / North Holland

Most polluted cities in North Holland, The Netherlands

7 measured cities, last 30 days; 0 above the WHO 24-hour guideline. Worst: Medemblik at 7.7 µg/m³, #1,055 in the world.

Ranked by unhealthy days: the share of each city's measured days with a daily mean over 35.4 µg/m³ (US AQI 101+), Unhealthy for Sensitive Groups or worse on the US EPA's scale. Ties go to the higher average.

South Holland: 8 measured citiesFlevolandGelderland: 2 measured citiesNorth Holland: 7 measured citiesFriesland: 1 measured cityUtrecht: 3 measured cities#6 Velsen-Zuid: 6.5 µg/m³#7 Haarlem: 6.5 µg/m³#5 Badhoevedorp: 6.6 µg/m³#4 Zaanstad: 7.1 µg/m³#3 Zwanenburg: 7.2 µg/m³#2 Amsterdam: 7.5 µg/m³#1 Medemblik: 7.7 µg/m³
Each dot is a measured city, coloured by its PM2.5; tap a dot to open the city.
← Medemblik 0% 0.75%0
Every measured city in North Holland, The Netherlands, one column each, ranked by unhealthy days: height is the share of its measured days that were unhealthy, colour its average. Point at it to read a city; tap to open it.
  1. 1Medemblik 0%
  2. 2Amsterdam 0%
  3. 3Zwanenburg 0%
  4. 4Zaanstad 0%
  5. 5Badhoevedorp 0%
  6. 6Velsen-Zuid 0%
  7. 6Haarlemlow-cost sensors 0%

Low-cost sensors: consumer units, counted only in cities with no government-grade monitor; they read close to reference monitors on the whole, but 15 to 25% high in humid air. How we use them.

Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

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

Estimated: cities without a monitor

North Holland cities we can't measure, with model estimates for the last 7 days. Listed by population, not ranked: estimates aren't precise enough to rank. Model estimates from the Copernicus Atmosphere Monitoring Service (CAMS), adjusted to measured cities nearby where there are any. Adjusted, a single day lands within ×1.5 of what a monitor would read about two times in three; unadjusted, it can be off by half or double. Treat them as a guide, not a measurement.

City7-day estimateBand
Hoofddorp≈ 9 µg/m³Good
Alkmaar≈ 7 µg/m³Good
Hilversum≈ 9 µg/m³Moderate
Purmerend≈ 9 µg/m³Good
Amstelveen≈ 9 µg/m³Good
Zaandam≈ 9 µg/m³Good
Hoorn≈ 7 µg/m³Good
Den Helder≈ 7 µg/m³Good
Heerhugowaard≈ 7 µg/m³Good
Huizen≈ 9 µg/m³Moderate
Heemskerk≈ 9 µg/m³Good
Beverwijk≈ 9 µg/m³Good
Castricum≈ 9 µg/m³Good
IJmuiden≈ 9 µg/m³Good
Nieuw-Vennep≈ 9 µg/m³Good
Bussum≈ 9 µg/m³Moderate
Bergen≈ 7 µg/m³Good
Uithoorn≈ 9 µg/m³Good
Heemstede≈ 9 µg/m³Good
Diemen≈ 9 µg/m³Good
Assendelft≈ 9 µg/m³Good
Heiloo≈ 7 µg/m³Good
Aalsmeer≈ 9 µg/m³Good
Volendam≈ 9 µg/m³Moderate
Schagen≈ 7 µg/m³Good
Weesp≈ 9 µg/m³Moderate
Enkhuizen≈ 7 µg/m³Good
Krommenie≈ 9 µg/m³Good
Naarden≈ 9 µg/m³Moderate
Zandvoort≈ 8 µg/m³Good
Velserbroek≈ 9 µg/m³Good
Julianadorp≈ 7 µg/m³Good

Bad-air episodes in North Holland

Times when many cities around here had PM2.5 at twice their usual or more on the same days.

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SmogRank, most polluted cities in North Holland, The Netherlands, PM2.5, last 30 days to 6 Oct 2026, 23:00 UTC, smogrank.com/nl/region/north-holland?w=30d.

Download top 10 (PNG)

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.

Updated 2026-10-06 23:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index.