What is the best plant for indoor air decontamination that is easy to grow?

I am thinking of getting a small plant for my bedroom to help with purification of the air from the general contaminants like formaldehyde, carbon monoxide, and whichever are other common air contaminants. I would like it to be small so that I can just put it on a bookshelf, and I would like it to be relatively easy to take care of. The room stays around 70 degrees. It's not very bright, but it does get some outside light. I already do have an air purifier in the room, which works very well, but I would also like a plant since my air purifier does not filter chemical air contaminants. Bonus points if the plant smells good and is easy to get.