3 plants- that would grow all the fresh air you need.
areca palm - 4 shoulder high plants per person - wipe the leaves - grow in water - take them outside every 3 months
mother-in-law's tongue - a good bedroom plant- converts CO2 into O2 at night - 6-8 waist high per person
money plant - hydroponics grown - removes formaldahydes and chemicals - and I've also heard that they remove nicotene and are good if we have a smoker in the house. These are also good in the bedroom.
In the Amazon, all these plants are HUGE, which is why I am posting it on this blog...shades of the jungle. According to Kamal, you could be sealed in your home with these plants and your blood oxygen levels would go UP!