Dust Documented
Daily PM2.5 peaked at 285.8 µg/m³ near El Paso across 1 covered metro home to 879,392 people. 1 metro placed a top-ten day in their record.
Counting the extra PM2.5 above each metro's typical day, this event handed the average affected resident ≈ 12.6 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
NWS and WMO evidence identifies a major March 18 El Paso Borderland wind, sand, and dust storm on the PM2.5 event date.
Documented An agency or publisher page assesses this cause, without an agency record naming the event or an EPA qualifier on the data.
U.S. Department of Agriculture · Mar 25, 2025 official
The federal bulletin identifies another major dust storm on March 18 and reports one-half-mile-or-less visibility in blowing dust at El Paso that day.
National Weather Service El Paso/Santa Teresa official
The NWS records a major March 18 wind and dust storm striking the Borderland, including east El Paso, with near-zero visibility from blowing sand and dust.
NOAA/NCEI Storm Events Database · Mar 18, 2025 corroborates
Visibility at the El Paso Airport ASOS was reduced to a quarter mile or less from 1243pm to 633pm.
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 federal bulletin identifies another major dust storm on March 18 and reports one-half-mile-or-less visibility in blowing dust at El Paso that day.
View supporting source ↗Air-mass movement
NOAA HYSPLIT modeled 12 backward paths across multiple arrival times and heights. They show where the air traveled, not which source polluted it.
Explore the modeled paths ↓Local response
The NWS records a major March 18 wind and dust storm striking the Borderland, including east El Paso, with near-zero visibility from blowing sand and dust.
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 2025-03-15 to 2025-03-21 · PM2.5 target: Ascarate Park SE
1444% above nearby days
180% higher than surrounding days
1733% higher than surrounding days
1444% higher than surrounding days
1733% higher than surrounding days
33% lower than surrounding days
65% lower than surrounding days
About the same as surrounding days
53% higher than surrounding days
13% lower than surrounding days
About the same as surrounding days
21% higher than surrounding days
180% 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.
Air-mass reconstruction
NOAA HYSPLIT traces the air arriving at each metro backward for 72 hours. Multiple arrival times and heights show whether the broad path is stable—or sensitive to assumptions about when and where the polluted layer arrived.
Air arriving near El Paso
Peak-date arrivals · 2025-03-18
Each line begins 72 hours before arrival and points toward the metro. Color represents arrival height; repeated lines represent 00, 06, 12, and 18 UTC arrival assumptions. A path can show where the air traveled, but it cannot prove which source added the PM2.5.
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 | 285.8 µg/m³ | 13.0 | Mar 18, 2025 | #2 of its top days |
"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.
U.S. Department of Agriculture
The federal bulletin identifies another major dust storm on March 18 and reports one-half-mile-or-less visibility in blowing dust at El Paso that day.
An official source supports the attributed cause for the stated place and dates.
The bulletin documents the dust occurrence and visibility impact, not the fraction of El Paso PM2.5 attributable to dust.
Cited authorities: National Weather Service El Paso/Santa Teresa
Documented An agency or publisher page assesses this cause, without an agency record naming the event or an EPA qualifier on the data.
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.