Sansevierias also known as Snake Plants are one of the best plants when it comes to air purification. They filter out formaldehyde and nitrogen oxide. They do this at night time making them great plants for the bedroom. Snake Plants are virtually indestructible unless you have a heavy hand with the watering can. Snake Plants seem to thrive on the dry air in our homes, as well as neglect. The more you ignore them, the better they do. Always make sure the soil is almost completely dry before thoroughly watering again.