When a foreign particle such as dust, pollen, bacteria or even pepper enter the nostrils and irritate the nasal mucosal lining, the human body’s reaction to get rid of the foreign particles is called a sneeze. Nerves in the nasal passage trigger a reaction by carrying signals to the “sneeze center” which is also known as the medulla and is located in the hindbrain. Your chest muscles then compress your lungs, which send a burst of air upwards. The throat shuts tight, which then sends the air shooting through your nose at speeds up to 100 mph. And let’s not forget the spray; there are 2,000 to 5,000 bacteria-filled droplets emanating from your nose and mouth when you sneeze.