Air Purifiers

I live in an extraordinarily polluted environment, and right now, the cost of breaking my lease and problems associated w/ relocating now would exceed the cost of this very expensive air purifier.
http://www.airpurifiers.com/products/iqair/gc-chemisorber.htm
If it works, it’s worth the money (esp. since I have chem sensitivities & allergies, so I’d probably find use for it anywhere), but if it doesn’t, it’s a huge waste for a glorified hepa filter (which is what it’d amount to if the chemical filtration didn’t work).
So my question is, how exactly does it filter out
Sulfur dioxide
Formaldehyde
Carbon dioxide
etc.
I’d be particularly interested to know how it can seriously filter Carbon dioxide, since that’s so prevalent in the air, I’d think that any filter for it’d be worn out within a day. That one in particular makes me question the validity of the product.
The sulfur dioxide, formaldehyde, and particulates from deisel are all very important to me, since these are some of the worst problems in this place, wedged between a factory w/ high sulfur dioxide emissions and an expressway, in a building full of gas stoves and heat, aside from fireplace smoke wafting in from the neighbors on some days.
Can someone with some knowledge of how these advanced air purifiers work please explain this to me? Would I be throwing my money away? (Please note that this is not a small purchase for me, especially looking at the cost and frequency of replacing the filters)