However, the air contains dust, germs, and other debris. If we breathe them in as they are, they can cause illness. Therefore, when we breathe in air, we must minimize the amount of dust before sending it into the body.
First of all, the many nose hairs in the nose prevent large debris from entering the body. The mucous membrane inside the nose also plays an important role. By keeping the mucous membranes moist at all times, even very small particles of dust and dirt are removed.
Thanks to these two factors, nose hairs and mucous membranes, we are able to send clean air into the body.
By the way, this small debris can stimulate the nerves in the mucous membrane of the nose. The stimulated nerve tries to shake off the debris on the mucous membrane to let it out, and exhales vigorously. This is sneezing.