просвещайтесь неучи
Then the difference? The biggest difference is indeed the characteristics that vary by concentration. In Shinsoo's case it's more like a gas when it's in low concentrations and more like liquid when it is in high concentrations. However, it seems air cannot be liquefied, even in high concentrations.
The second difference is the circulation. The circulation of Shinsoo is very fluent but there is no common law and the movements are all different, depending on the Floor of the Tower you are on. However, it is said that there are set laws in the circulation of air. (I want to study some more about the laws, but the research is slow because none of the Irregulars that I have met are knowledgeable enough about the laws of air.)
The third difference is consumption. Shinsoo exists everywhere inside the Tower. So Shinsoo exists even in a room that is completely sealed. Shinsoo does not flow in from somewhere else, but is rather created from the Tower. Thus, Shinsoo even exists within a vacuum. Air is not created from sealed places and, if a being is locked inside a sealed room, the being will consume all of the air and die. (It seems very uncomfortable.)"