https://doi.org/10.1351/goldbook.D01867
Small, dry, solid particles projected into the air by natural forces, such as wind, volcanic eruption and by mechanical or man-made processes such as crushing, grinding, milling, drilling, demolition, shoveling, conveying, screening, bagging and sweeping. Dust particles are usually in the size range from about in diameter and they settle slowly under the influence of gravity.