These are what you need,
1. Used washing net, for those who have no idea ask your mum.
2. Charcoal. About 3 to 5 KG
3. Few aluminum foil plate
Stuff the charcoal in the washing net and then put them on a plate. Place one of each in every room highest spot you can find. Forget them. Now you will have a purified room in no time.
Charcoal is a natural toxic gas and chemical absorber. It is also cheap and plentiful.
There are also some creative ways that you can reduce carbon generated by your PC. Simply put a piece of it inside your CPU. Brilliant idea?