Sneezing is a procedure of expelling the harmful bacteria and virus which has entered the body and multiply themselves during cold, allergic reactions or when dust blows on our face.
Nose acts as a purifier and cleanses the air that have bacteria and dust particle. A chemical named HISTAMINE is created by inflammatory cells in the nose. So the nerve endings send impulse to brain that something has entered that should not be there. Now brain send message to chest muscle to squeeze the lungs and pharynx also shuts down to prevent the air being squeezed to the mouth. Nose expels these particles with the blast of air that is called sneezing and clears the passage.
Some people start sneezing in the bright sunlight because a reaction between the nose lining and ultraviolet rays take place. This may have inherited by a child from his parents.
Excessive sneezing can be reduced by using saline solution or you can hold your nose softly from the end.
Many people close their eyes while sneezing and others can sneeze without closing. It is a reflex action of our body and hence is not under our control. It is said that while closing our eyes we prevent the germs and bacteria, which is not true. So we can sum up with that sneezing at times is good for our lungs as it clears the passage.