Question
I want to buy a plant for my granddaughters room that will filter and provide the most oxygen.

Thanks

Answer
Mario,

Here is a list of house plants that are about equal in oxygenating the room. The Nasa website with more info is at:
http://www.extension.umn.edu/projects/yardandgarden/ygbriefs/h110indoorair.html

Hedera helix                      English ivy
Chlorophytum comosum              spider plant
Epipiremnum aureum                golden pothos
Spathiphyllum 'Mauna Loa'         peace lily
Aglaonema modestum                Chinese evergreen
Chamaedorea sefritzii             bamboo or reed palm
Sansevieria trifasciata           snake plant
Philodendron scandens 'oxycardium'   heartleaf philodendron
Philodendron selloum              selloum philodendron
Philodendron domesticum           elephant ear philodendron
Dracaena marginata                red-edged dracaena
Dracaena fragrans 'Massangeana'   cornstalk dracaena
Dracaena deremensis 'Janet Craig' Janet Craig dracaena
Dracaena deremensis 'Warneckii'   Warneck dracaena
Ficus benjamina  weeping fig

Good luck.
Darlene