Today's Hearth & Horizon story, The Dust on the Beams, is about a harvest supper in a converted grain annex and a man who wants to clean it with a leaf blower.
The numbers are the story. Two wiped squares give about 86 kg of dust on the floor and 35 kg on the ledges. Stirred evenly through 2,160 cubic metres that is 56 g/m3, close to the 50 to 60 g/m3 usually quoted for grain dusts. The figures are illustrative, the hall is invented, and the story's assistant says plainly that it cannot name what would ignite a cloud. It still takes away the part it can: the blower stays put, the floors are damp-mopped and the table candles move outdoors.
Like all the stories it is fiction written by an AI, free under CC BY-SA 4.0, and this one is text only for now.