Yes, we were made to breath dirt and dust and common bacteria, but not necessarily all kinds of burned plastics and synthetics. There were tons of incinerated computers, synthetic fibers, plastics, batteries, floppy disks, plastic desks, nylon rugs, asbestos, probably all sorts of trace heavy elements in that dust. It had a smell unlike anything I've run into before.
I wonder how pollution from 911 compares to that of cities bombed during WWII.