I don't know how effective they are compared to these devices, but I much prefer to keep plants with air purifying qualities. NASA did a study on a variety of air purifying plants in 1989: https://ntrs.nasa.gov/search.jsp?R=19930073077
You would need to live in an indoor rainforest (approximately 680 plants for a typical house) to see an effect on air quality, a spider plant in the corner isn't doing anything: https://www.youtube.com/watch?v=AmeiXikh0v8
That's an interesting study, but it appears to only study the plants' ability to filter out a few VOCs. HEPA filters won't help with those (you need an activated charcoal filter for that... or plants, I guess?), but they will help with particulates, and I'm not sure plants will do anything for those.
there's still a bunch you can buy. apparently many "toxic" plants are only mildly toxic for cats/dogs.
i don't think they make much difference for air quality, but i bought some "air purifying" plants and cross-checked them against the aspca list for safety:
minikites|6 years ago
csytan|6 years ago
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compressedgas|6 years ago
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clairity|6 years ago
i don't think they make much difference for air quality, but i bought some "air purifying" plants and cross-checked them against the aspca list for safety:
https://www.aspca.org/pet-care/animal-poison-control
(my cat likes to munch on my spider plants, even with cat grass available)