Dust High confidence
Daily PM2.5 peaked at 288.5 µg/m³ near El Paso across 1 covered metro home to 879,392 people. 1 metro recorded their worst day on record.
Counting the extra PM2.5 above each metro's typical day, this event handed the average affected resident ≈ 12.7 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 11 million cigarettes. An awareness illustration of outdoor exposure at 22 µg/m³ per cigarette (Berkeley Earth), counting only the event's ranked days; not a medical dose.
Why we think this happened
An exact official dust advisory and independent contemporaneous local reporting identify a severe windblown-dust event in El Paso.
High confidence At least two independent causal origins and evidence families agree on this cause.
National Weather Service via weatherUSA · Apr 1, 2025 official
The NWS advisory for April 1 identifies blowing dust across El Paso County, visibility of one-quarter to one mile, and gusts near 60 mph.
National Weather Service El Paso/Santa Teresa official
The NWS reports that a powerful April 1–4 storm brought very strong winds and considerable blowing dust to the El Paso region. It does not itself quantify the event PM2.5 contribution.
KVIA · Apr 1, 2025 corroborates
Contemporaneous El Paso reporting says strong winds produced blowing dust and sand and reduced visibility to roughly one-quarter mile.
Evidence path
A cause is more convincing when the record connects three things: something happened, the air mass moved toward the region, and local instruments responded. Here is how much of that chain is documented for this event.
Source or mechanism
The NWS advisory for April 1 identifies blowing dust across El Paso County, visibility of one-quarter to one mile, and gusts near 60 mph.
View supporting source ↗Air-mass movement
The retained record does not yet show how air traveled from the proposed source to these metros. A trajectory replay or dated plume analysis belongs here.
Local response
The NWS reports that a powerful April 1–4 storm brought very strong winds and considerable blowing dust to the El Paso region. It does not itself quantify the event PM2.5 contribution.
Inspect the pollutant and weather signals ↓Event autopsy
Before, during, and after the episode: nearby pollutant monitors and surface-weather stations show what changed. This context tests the “Dust” explanation; it does not assign the cause by itself.
El Paso, TX
Monitor comparison window 2025-03-29 to 2025-04-04 · PM2.5 target: El Paso Chamizal
556% above nearby days
72% higher than surrounding days
1379% higher than surrounding days
556% higher than surrounding days
1379% higher than surrounding days
13% lower than surrounding days
43% higher than surrounding days
30% higher than surrounding days
About the same as surrounding days
5% higher than surrounding days
About the same as surrounding days
About the same as surrounding days
72% higher than surrounding days
Source: U.S. EPA AirData daily observations and, where available, nearby ASOS/AWOS surface observations. Values are descriptive medians over the retained monitor set; missing measurements remain missing. Transport and source evidence remain separate layers because this instrument pattern does not assign a cause by itself.
Episode peak
-- cigarettes
The smoke map's scale, replayed over this event: the surface interpolates between covered metros' daily records, framed to the affected region. Hover for a reading, click a metro to pin it to the card. Days a monitor did not report draw nothing.
Views from the selected metro
Select a metro on the map to see nearby cameras. Where an operator archive reaches the event, drag the divider to compare two moments, adjust either date and time, or play the available event-day frames. Camera imagery is visual context, not an air-quality measurement or proof of smoke.
No useful public camera views are currently available within 80 km of this metro.
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| El Paso, TX | 288.5 µg/m³ | 13.1 | Apr 1, 2025 | Worst day on record |
"Cigarettes, whole event" totals a metro's ranked event days at 22 µg/m³ per cigarette: what a person outdoors there breathed across the event, as the illustration. "All-time standing" is where this episode's days sit in each metro's ranked record (worst-area measure, since 1999). Full local context is on each metro's Air Records page.
Public evidence library
Each card states what a source supports—and what it does not. Official records, research, reporting, community observations, and transparent inferences remain visibly different kinds of evidence.
National Weather Service via weatherUSA
The NWS advisory for April 1 identifies blowing dust across El Paso County, visibility of one-quarter to one mile, and gusts near 60 mph.
An official source supports the attributed cause for the stated place and dates.
The canonical NWS alert is preserved through an alert mirror.
KVIA
Contemporaneous El Paso reporting says strong winds produced blowing dust and sand and reduced visibility to roughly one-quarter mile.
A retained source supports the attributed cause for the stated place and dates.
The report does not apportion the certified daily PM2.5 mass by source.
High confidence At least two independent causal origins and evidence families agree on this cause.
This episode was grouped from the monitor record by the catalog pipeline and given its cause from the evidence listed above. It has not been individually reviewed and signed off, so its boundaries, cause, and name may change as evidence accumulates. Grouping policy common_sense_root_cause_grouping.v2. The cause label reflects the assembled evidence above, not an IAQng detection formula. If it is wrong, tell us.