Why Do We Sneeze?

Sneezing is a procedure by which foreign particles, harmful bacteria, viruses etc. that have accumulated in your nasal passage due to a cold or allergic reactions or the blowing of dust in your face are expelled and is a reflex action - an action that is done automatically over which you do not have any control. When there are foreign material in your nose a chemical called histamine is produced which sends signals to the brain that there are material that should not be there. The brain now sends out a message to the lungs to squeeze them and also shuts down the pharynx to prevent air from being squeezed through the mouth. The nose expels these foreign material with a blast of air that may at times reach speeds of some 950 km/hr.