Some kinda current fad to talk about. People are getting carried away and making all kinds of outrageous statements. Let's start wit the best list I have seen so far from NASA's research::

http://www.healthyandnaturalwo...

On a national TV show Green (something or other) they suggested you put a cactus in your office cubical which will give you cleaner air. HA.
A - I would never suggest anyone put a cactus in an office cubical. I suppose somewhere there is a cubical with enough light but I kind of doubt it.
B - What is the cubic foot volume of the room our cubical is in? Even if you brought in the most efficient plants, how many would you need to make a difference?
C - Oh wait a minute - that air is constantly being exchanged with the same type air from the rest of the building. Guess we need to talk about the total volume of your building !
D - I live in a small house (1400 sq. ft.) and have about 450 pots of Sansevieria - which is on that NASA list. Do I get cleaner air? Who knows. Maybe?? I do not own a meter that would tell me the answer.

People, people, people. Get real. Yes, it is nice to know that plants can help. Use that or any other "fact" if you need to explain to your roommate, spouse, kids why you have plants, I guess.

Gene

What you are writing is all true, Gene. This NASA stuff is being promulgated by the indoor plant industry (of which I am a part) because it enhances plant sales. The media picks it up because it makes for lots of human interest. There are many good reasons to own house plants, but cleaning the air is not an important one.

It really is sad to see so many jumping on this greatly exaggerated fact as a marketing trick. I find I naturally jump to the conclusion a seller is either dishonest or not very bright if they are pushing the clean air card on the internet.

Gene, you are so right.

I do believe that I bring enough plants into my house to make a difference, but like Gene said, I have no way of measuring anything, and my environment is rarely closed. It's a creaky, leaky old house and if the temp outside is between 65-85, which it is most of the year, the windows are open.

Any plant that grows quickly, or at least uses a large volume of water quickly, should be metabolizing quickly, so those are the ones that I would expect to produce the most effect. If so, I would not expect cactus or other relatively slow-growing plants like Sansevieria to be able to do what the same mass of palm or Philodendron leaves could do, as far as removing toxins from the air and/or producing oxygen.

One can easily realize without reading any research that some plants are better than none, and a lot of plants are better than just a few. But as far as being a marketing point, it's meaningless to me. There's nothing in my house that is new enough to be off-gassing specific chemicals, or a seal so tight that would limit the exchange of outside air. If I'm wanting to improve general indoor air quality, I think I should be looking for increased mass of any type of plant instead of a particular type of plant.

The research being done by NASA is very real but I am also skeptical about extrapolating that into being applicable in a prescriptive way to the average living room, kitchen, bedroom, where there are so many variables that there is really no such thing as the average room.

And another thing I've been wondering for years regarding the NASA list is if it is a list of the only plants that they tested, or were there a lot more but only these produced desired results? I think they are/were looking for plants to remove specific toxins from the air, but I am really not sure.

That's part of what I love about someone suggesting using a cactus. A slow growing plant. Probably the bottom of the cleans air list. Gene

The NASA studies were done in carefully controlled lab environments that are not at all like our homes. Not clear how the plants used in the study were slected, but the vast majority of plant species were not used so we no nothing about those species.

Plants that have lots of total leaf surface (larger plants, Ficus benjamina) remove more pollutants as do plants that are healthy and growing vigorously.

But that saleslady said I'd suffocate if I didn't buy her plant! You mean she lied???

I like plants in my house because plants = outdoors = clean air. I know it doesn't really do anything, but I like to think it does. And with the zoo we have, any bit of delusion is welcome.

I always try to push the idea that plants are great for our inside environments because they bring visual and sometimes aromatic pleasure If you need clean air go outside!

Oh, it more complicated than that. I have plants with aromatic foliage that "stink" up the room every time you water them. I teach classes on house plants. Usually at my house. Once, when class was over a man asked me if he could bring his wife out on another day. She just has to see all of this. We set up a time later that week. They arrived. She's blind. Tactile. Having growing things, things that change around you is good therapy. Kinda like pets. Gene

That's a good point Gene.

very special, Gene.

Clean air outside?! That's another matter altogether.

WillC said:Clean air outside?! That's another matter altogether.

Well better than stale, dusty indoor air.

An assumption not valid! There are so many places where I have been and read about where the outdoor air is dangerous. OK, maybe not in the Mid West. We re indeed spoiled. Gene