Right now
The most recent data we hold from AIRNOW arrived 6 hours ago, and this point is in it.
One other detection within 20 km in the last 24 hours, <1 km from here.
Reported by AIRNOW today.
No stronger detection stands among the 11 recorded within 20 km of this point since 18 April 2026 — 10 others scored the same. The last comparable one was on 27 September 2026. 10 more were recorded here in the fortnight before it.
What the source measured
AIRNOW reported: AQI: 147 (Unhealthy for Sensitive Groups) · PM2.5 AQI: 55 · Ozone AQI: 147
Urban PEI: 1,312,076 within a heuristic 5 km radius; not unique people.
At this point we have recorded a air quality index between 105 and 182, over 6 readings since 27 September 2026. Today's reading sits 55% of the way up that range.
Nearby, since 18 April 2026
- September 27, 2026 · score 50 · 0.0 km
- September 26, 2026 · score 50 · 0.0 km
- September 24, 2026 · score 50 · 0.0 km
How we know
One source: AIRNOW. Not yet confirmed by a second, independent source.
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 | Low |
| Calamity Score (ours) | 50 / 100 |
| Legacy data-support index | 0.70/1 |
| Coordinates | 29.7510, -95.3510 |
| Nearest City | Houston (1 km) |
| Urban exposure index (PEI) | 1.3M within 5 km |
| Impact Tier | minor |
| Timestamp | 2026-09-28T00:00:00.000Z |
| Source | https://www.airnow.gov/ |
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: airnow. Occurrence: 2026-09-28T00:00:00.000Z.
First archived: 2026-09-27T19:34:44.561Z. Material modification: 2026-09-28T00:39:53.796Z.
Retained revisions are prospective; earlier versions may be unavailable. No revision entry does not prove that a record never changed.
2026-09-27T23:41:51.433Z · data_change
Index 59 → 50; severity medium → low.
2026-09-27T22:37:50.414Z · data_change
Index 50 → 59; severity low → medium.
3 retained revisions changed source fields this page does not show; the index, severity and version stayed the same.
Score Breakdown
Technical Details
| Aqi | 147 |
| Pm25Aqi | 55 |
| OzoneAqi | 147 |
| CategoryName | Unhealthy for Sensitive Groups |
| ReportingArea | Houston-Galveston-Brazoria |
| StateCode | TX |
| City | Houston |
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.
Want to know when something happens near Houston?