Picture someone holding their nose up in the air - they look very aloof and snobbish, right? That's what this idiom means.
to be stuck up
Nose hair filters air that is passing through the nose, for example, dust particles in the air.
When scabs are present in the nose it is usually due to dry air and lack of moisture in the nasal passages. If the nose is dry for an extended period it will crack and bleed causing scabs.
The fine nose hair and the mucus. The mucus moist the air and the nose hair traps the dust and cleans the air.
you don't breath in air with the help of your nose the time.
Air inhaled through the mouth is not as clean as air inhaled through the nose. Reason for this is that when we inhale air through our nose than it get filtered by hair present in our nose. But air inhaled through our mouth goes directly in without any filtration.
The tiny hairs in our nose clean the dust particles in the air
If your nose is up in the air (snooty or snobbish) then to look at a lesser, you would have to look down your nose at them. Hence, looking down on someone or something.
inside the nose, tiny hairs clean the air by catching dirt and other particles. the air also warms as it travels through the nose.
Up your b-hind or kiss my b-hind.
This is normal; the nasal passages, mouth and eyes are all connected.
the air has to go through your nose and the hair in your nose cleans the dust and every thing thatsshouldn't get into your nose and your system!!