It was grass smoke this evening polluting our air. Somebody had to burn grass under cover of darkness. I do not know who was burning yard waste tonight, but there is only one household that I know of that does that this late.
5:00 PM: No smoke. 85 degrees, sunny.
7:20 PM: No smoke.
8:15 PM: No wood or grass smoke yet.
9:00 PM: A very faint trace of something is in the air. It is not strong enough to determine what it is. The air is not fresh.
10:00 PM: Moderate grass smoke. Someone is burning grass. Grass smoke does not often get as strong as this.
10:45 PM: Faint grass smoke continues.
11:30 PM: A very faint smokiness and a lighter fluid smell is in the air. Last check of the night.