Right now
The most recent data we hold from World Air Quality Index arrived 19 minutes ago, and this point is not in it. We record detections, not passes: an absence is not proof that nothing is there.
One other detection within 20 km in the last 24 hours, 24 km from here.
Reported by World Air Quality Index today.
It is one of only 3 we have recorded within 20 km of this point since 9 March 2026. The last comparable one was on 25 September 2026. One more was recorded here in the fortnight before it.
What the source measured
World Air Quality Index reported: AQI 154 (Unhealthy) at De Ruyterstraat, Nijmegen
The air quality index read 154 (Unhealthy) at the De Ruyterstraat, Nijmegen station.
Urban PEI: 121,052 within a heuristic 5 km radius; not unique people.
How we know
2 recorded sources include World Air Quality Index; independence is not established by this count.
Our own score for this event is 50 out of 100.
This is our versioned heuristic index, not source severity or a calibrated probability. Urban PEI does not count unique people.
Computed under scoring rules v5. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | Air Quality |
| Severity | Medium |
| Calamity Score (ours) | 50 / 100 |
| Legacy data-support index | 0.72/1 |
| Coordinates | 51.8382, 5.8569 |
| Nearest City | Nijmegen (1 km) |
| Urban exposure index (PEI) | 121.1K within 5 km |
| Impact Tier | significant |
| Timestamp | 2026-09-30T09:00:00.000Z |
| Source | https://aqicn.org/city/@6477 |
Physical priority index · v5. Heuristic priority, not calibrated probability, predictive accuracy or damage. The legacy data-support index combines assigned source support and field availability. Urban PEI is distance-weighted and does not count unique people; zero does not establish that nobody is present. Model cards.
Source and revision timeline
Source: waqi. Occurrence: 2026-09-30T09:00:00.000Z.
First archived: 2026-09-30T09:09:25.233Z. Material modification: not recorded.
Retained revisions are prospective; earlier versions may be unavailable. No revision entry does not prove that a record never changed.
2 retained revisions changed source fields this page does not show; the index, severity and version stayed the same.
Score Breakdown
Technical Details
| Aqi | 154 |
| AqiCategory | Unhealthy |
| StationName | De Ruyterstraat, Nijmegen |
| StationUid | 6477 |
| Network | official |
| Sensor Community Pm25Median | 400.4 |
| Sensor Community Pm25Max | 557.47 |
| Sensor Community Pm25Avg | 321.1 |
| Sensor Community SensorCount | 3 |
| Sensor Community SensorsAbove | 2 |
| Sensor Community Network | civic |
| Sensor Community AqiCategory | Hazardous |
| Sensor Community AqiCategoryVersion | US-EPA-PM25-2024-05-06 |
| Sensor Community MeasurementUnit | ug/m3 |
| Sensor Community AveragingPeriod | 24h |
| Sensor Community Aggregation | median of the cell's outdoor sensor 24h means; published when at least two agree and are the majority |
| Sensor Community SelectionThreshold | 55 |
| Sensor Community ClusterKey | 52.0_6.1 |
| MergedSources | [{"id":"sensor_community_52.0_6.1","source":"sensor_community","severity":"medium","severityValue":65,"timestamp":1790762388000,"latitude":51.98366736666666,"longitude":6.114167999999999}] |
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.
Review the area, threshold and delivery channel in your account.
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