My 8 year old sons nose is bleeding, what is the cause? and what can i do to stop it from bleeding

Nose bleeds are : Common in middle childhood & often reflect irritants like dust, pollen, fumes, smoke etc that the kid is exposed to on a regular basis.These things accumulate in the nasal passages & lead to nasal rubbing when the kids are half asleep or during the day.The trauma causes small capillaries in the nose to bled. Pinch the nose & it should stop. Use a nasal saline gel/wash to reduce future issues.