evidence: It turns out the hardy snake plant suffers from an overgrowth of hype. It's a bit of a potted star on the Internet and Facebook, where it's promoted as a top plant for cleaning indoor air: "Snake plants are extremely good air purifiers! Ask NASA!" said one posting from July. [...] Much of the current ballyhoo about snake plants seems linked to a 1989 NASA study. With an eye to people being sealed in a space chamber, it studied the ability of more than a dozen houseplants, including the snake plant and gerbera daisies, to remove volatile organic compounds such as benzene and formaldehyde. They plants "demonstrated the potential for improving indoor air quality," it concluded. The study didn't look at carbon dioxide. [...] When told about research finding that a few plants don't actually clean indoor air, he provided a 2018 article from the website of a company in India that sells houseplants: "Snake Plant: Everything You Need to Know." That article, like others, refers to the NASA study and calls the snake plant an "Air Purifier Approved by NASA."