Dust is a general name for minute soli particles with diameters less than 500 micrometers. Dust occurs in the atmosphere from various sources such as soil dust lifted up by wind, volcanic eruptions, and pollution. Dust in homes, offices, and other human environments consists of human skin cells, plant pollen, human and animal hairs, textile fibers, paper fibers, minerals from outdoor soil and dust, and many other materials which may be found in the local environment.