# Saint Louis wildfire smoke and air quality

Live readings for Saint Louis, Missouri from SmokeDar (https://smokedar.com/saint-louis): whether
wildfire smoke is overhead, what the surface air measures, and how the next five days look.
Free, no signup, no ads.

## How smoke reaches Saint Louis

Saint Louis is among the last stops for Canadian smoke, which arrives old, high, and diluted, and it also catches Western US smoke on the westerlies. The bigger local risk is stagnation: hot, still spells that let any arriving haze pile onto the metro's own summer particle load.

That is why SmokeDar reports two numbers for Saint Louis:

- **Smoke aloft**: modeled aerosol optical depth from Copernicus CAMS. This explains the color of the sky.
- **Surface air**: PM2.5 and US AQI, using observed AirNow monitor data when a monitor is nearby. This is what reaches your lungs.

They are different things, and they often disagree. An orange sky can sit over clean surface air,
and hazy-looking days can measure fine.

## Is the air in Saint Louis safe to breathe today?

Use the US AQI number, not the sky's color:

- **0-50 (Good) and 51-100 (Moderate)**: ordinary days for most people.
- **101-150 (Unhealthy for sensitive groups)**: kids, older adults, pregnant people, and anyone with heart or lung conditions should shorten hard outdoor exercise.
- **151+ (Unhealthy and above)**: everyone should cut both time and intensity outdoors.

The current live reading is on https://smokedar.com/saint-louis and the full playbook is at
https://smokedar.com/smoke-guide.html.

## About SmokeDar

SmokeDar is a free wildfire smoke and air quality radar covering 21 cities across the eight
Midwest states (Minnesota, Wisconsin, Michigan, Iowa, Illinois, Indiana, Ohio, Missouri).
Built by Ryan Thompson in Milwaukee. It is not a health barometer; readings are modeled or
monitor-observed as labeled. More: https://smokedar.com/llms.txt