Right now
The most recent data we hold from World Air Quality Index arrived 2 hours ago, and this point is not in it. We record detections, not passes: an absence is not proof that nothing is there.
Nothing else has been detected within 20 km in the last 24 hours.
Reported by World Air Quality Index today.
It is the strongest of the 11 detections recorded within 20 km of this point since 10 March 2026. The last comparable one was on 29 August 2026.
What the source measured
World Air Quality Index reported: AQI 154 (Unhealthy) at Binnen
The air quality index read 154 (Unhealthy) at the Binnen station.
An estimated 88,756 people live within 5 km of this point.
How we know
Confirmed by 2 independent sources, including World Air Quality Index.
Our own score for this event is 46 out of 100, at 65 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Computed under scoring rules v4. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | Air Quality |
| Severity | Critical |
| Calamity Score (ours) | 46 / 100 |
| Our confidence | 65% |
| Coordinates | 52.1523, 4.5029 |
| Nearest City | Leiden (1 km) |
| Population Exposed | 88.8K within 5 km |
| Impact Tier | severe |
| Timestamp | 2026-09-06T15:55:15.000Z |
| Source | https://aqicn.org/city/@-2500741 |
Score Breakdown
Technical Details
| Aqi | 154 |
| AqiCategory | Unhealthy |
| StationName | Binnen |
| StationUid | -2500741 |
| Sensor Community Pm25Max | 594.86 |
| Sensor Community Pm25Avg | 521.6 |
| Sensor Community SensorCount | 2 |
| Sensor Community AqiCategory | Hazardous |
| Sensor Community ClusterKey | 52.0_4.7 |
| MergedSources | [{"id":"sensor_community_52.0_4.7","source":"sensor_community","severity":"critical","severityValue":90.8972,"timestamp":1788710355000,"latitude":52.027132262165,"longitude":4.719721660615}] |
Safety Information
When air quality is hazardous: stay indoors with windows closed, and run a filtered air purifier if you have one. Avoid outdoor exercise. Children, older adults and anyone with heart or lung conditions are affected first and worst — an N95 respirator helps outdoors, a cloth mask does not.
Series begins 8 March 2026. Comparisons refer to that period only. Collection gap: 14-26 August 2026.
This data is aggregated algorithmically from scientific sources. Not a replacement for official emergency warnings.
Want to know when something happens near Leiden?
Calamity.live data shows a air quality event with CalamityScore 46/100, near Leiden (Netherlands), based on data from waqi. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.