Hi - Welcome to the gang. Dust collection has a lot of things that need considering to engineer the system correctly. Here is a book that can give you a decent place to start:
Then you might give Bill Pence's website a look, although he may scare you a bit.
Something to think about: a 2 HP dust collector can change or exhaust the air in a 40 x 40 foot shop in 20 minutes. If you are going to air condition you shop, you are going to need a way to return the air the DC is moving back to the shop.
I think it is pyrolized wood, a type of heat treatment that colors the wood all the way through. It also renders the wood rot resistant without using chemicals.
i think the wood has to be heated in a chamber without oxygen or some special atmosphere.