Diffusion: Really fine particles measuring below 0.one micron get bounced about randomly and they are slowed by their interactions with atmospheric atoms and molecules. They finally drift or get bounced into a filter fiber, whereupon (over again) they stick inside of a method identified as diffusion. ฝุ่นละออง, เชื้อรา, ละอองเกสร และแบคทีเรีย https://www.mannature.com