I don't know, but I wonder if you can contact the company and see if that system is safe for propane and heavy metal fumes.
It seems pretty pricey!
There is a blog entry by Andrea Guarino? where she has someone help her come up with a portable system that she uses but the vented air does go outside her studio through a moveable tube if I remember right.
OK, I found the link. Maybe this would work for you?
http://www.andreaguarino.com/read-me/