Is there a word for "air can pass through it"?
If light can pass through an object, or if you can see through it, it is transparent.
Is there a similar word for "air can pass through", or you can breathe through an object? This adjective would be used to describe a screen door, or certain types of fabric.
Solution 1:
permeable if the pores are small
allowing liquids or gases to pass through; capable of being permeated; penetrable; especially: having pores or openings that permit liquids or gases to pass through
breathable if it's a fabric
Permitting air to pass through: a breathable fabric.
I don't know what to call this property in a screen door...
apologies to @James McLeod - I didn't read the entire question and jumped on permeable.
Solution 2:
Rather to my disgust (as some who grew up reading a great deal of science fiction), the industry-accepted term for this is "breathable."
I know this is ugly and misleading, but it's the word.