Wildfire smoke field guide
Smoke Plume vs Ground-Level PM2.5: why satellite smoke does not equal local air quality.
A satellite can see a smoke plume in the atmosphere while surface monitors show much lower particle concentrations below it. Plume presence and breathing-level exposure are different measurements.
Core distinction
Smoke aloft vs particles where people breathe.
AirNow explicitly notes that satellite-detected smoke plumes indicate atmospheric smoke that may not affect ground-level air quality.
Shows smoke visible from space in the atmospheric column. It says little by itself about the vertical height of the smoke relative to people at the surface.
Measured or estimated fine-particle concentration near the surface, where exposure occurs.
Why they diverge
Vertical mixing controls whether smoke reaches the surface.
- Smoke can remain elevated above a stable surface layer.
- Daytime mixing can later bring elevated smoke downward.
- Wind can transport smoke far from the fire before it mixes to the ground.
- Terrain and inversions can concentrate smoke in valleys.
- Satellite plume detection can be limited by darkness and cloud cover.
Visible plume ≠ AQI reading. Use surface monitors and validated sensor information for local air-quality decisions.
Use the right layer
Map smoke transport and exposure separately.
Source
AirNow Fire and Smoke Map.
Published 21 September 2026.