The Myth of the "Clean Air Plants"
I'm sure we've all heard this (or similar) claims:
Almost none of this is true.
(The only sentence that's actually true is the second one -- spider plants are (often) under $20, and they can absorb chemicals like formaldehyde.)
So what about the rest of it?
Short version:
Houseplants do not purify the air in your house in any appreciable way.
Long version:
Spider plants cannot absorb "95% of chemicals". "Chemicals" is completely meaningless here; air itself is a chemical. So is water vapour.
What this meme means is pollutants, or VOCs (volatile organic compounds).
Beyond that -- "95%" is meaningless without a lot more information. What chemicals? How much of each are you putting into the air for the spider plant to absorb? How big is this spider plant? How much light is it getting? Etc, etc.
Most importantly, the idea of houseplants as being able to "purify the air" is based on a single, *extremely* flawed study by NASA years ago (the aptly-named NASA Clean Air Study).
The plants were put in a very, very small box, which then had different pollutants pumped into it (such as formaldehyde) -- at rates FAR higher than would occur in your home (well, if you survived, at least). The plants ARE able to absorb those pollutants, but not that quickly, and the results just can't be extrapolated to a house -- it was a closed environment, while houses are (of course) pretty open environments that have continuous gas exchange with the outdoors.
The claim that one spider plant can purify a 200sqft room is completely made up. To see any appreciable increase in air quality, you'd need to have (for a 1500sqft, 2-3 bedroom house) about 700 plants -- if it doesn't look like a rainforest, then the gas exchange with the outdoors is doing the heavy lifting for removing any pollutants from the air, not your plants.
Finally: spider plants were one of the plants tested, but were not even among the best at removing VOCs. Bigger plants with broader leaves fared better -- think Aglaonemas, not spider plants.
I'm rating this meme exactly 0/10, because I'm guessing they were only accidentally accurate in the second sentence.