How does nose protect you from pathogens?
Your nose has a defense mechanism that protects against pathogens: hair and mucus. The hair in your nostrils helps catch airborne bacteria as you breathe in and out of your nose. The mucus passes through the hair in your nostrils, and then, when you blow your nose, the mucus contains pathogens that make you sick. This is not a 100% effective system, because people get sick all the time.