Question

why is the air entering the lungs dust free

Answer 1

 When we breathe through the nose, air moves into the nasal cavity and sinuses where many airborne particles are trapped by a thin layer of mucus that lines the surface of the air passages.

Answer 2

a) The air passing through the nostrils is filtered by the fine hair that lines the passage.

b)It also becomes moist and warm .

c)The dust particles are trapped in the mucus.

d)Thus, air entering the lungs is dust free.