I wrote a book about life force ideas around the world, and found that they can be sorted into categories. One of those categories is air based life force ideas, such as qi, ki, prana, spirit, ruach, and so on.
These concepts have great similarities, so I dare say that they have more to do with common human traits and circumstances than with cultural differences.
Here's the book, by the way:
http://www.amazon.com/dp/1439200688/