A mass of dust is a CLOUD-like formation of tiny particles of dust suspended in the air. It is usually composed of small particles of sand, soil, and other materials that are too small to be seen individually. Masses of dust can form in a variety of ways, such as from wind erosion, volcanic eruptions, or industrial activities. They can also be created by the movement of air masses, which can cause the dust particles to become airborne. Masses of dust can have a significant impact on the environment, as they can reduce visibility, cause respiratory problems, and even damage crops.