Each layer answers a different question
The fire perimeter shows where land has burned. Satellite imagery shows smoke moving through the atmosphere. Ground monitors and corrected sensors estimate what people nearby are actually breathing. Smoke can travel hundreds of miles, and an ominous plume overhead does not always produce the worst air reading at street level.
Read the fine print on the map
AirNow puts several kinds of information in one place, but they are not equally precise or updated at the same time. Before comparing two towns, check the legend, the timestamp and whether conditions are getting better or worse.
- The current Air Quality Index and main pollutant
- Whether the reading comes from a monitor or sensor
- The recent trend and forecast
- Advice for your health needs and activity level
Use the map to make a choice
The point is not to admire a dramatic plume. It is to decide whether to close the windows, move a workout indoors or reduce your exposure. Give the ground-level reading the weight it deserves.