8:00 PM: No wood smoke yet. 80 degrees. A beautiful summer evening.
9:00 PM: A faint odor is in the air. I can't tell what it is. It doesn't smell like wood smoke. If it is wood smoke, it is from a far away burner.
10:00 PM: Faint odor of something remains in the air. 75 degrees.
11:00 PM: Faint odor of something remains.
This will count as a day without wood smoke. It is very rare to have a nice evening without wood smoke.