Dust mites are microscopic organisms that live in dust. These unwelcome visitors invade your nose and can irritate your mucous membranes, triggering nerve cells that signal the lungs to fill with air. When the air passages close and pressure builds up, your nose tingles and twitches, and you sneeze forcing mucus (the slimy, moisturizing substance), dust, pollen, and mites out of your nose at speeds of up to 525 feet (160 meters) per second! Sneezing is one of the body’s reflexes, an automatic way it rids itself of harmful substances like bacteria and germs. It also keeps the tubes that carry the air from your nose to your lungs healthy.