I found this report while looking for productive air cleaning house plants. I’ve never been a huge fan of plants because they just collect dust. Alas! These plants do so much more!
15 indoor plants that Purify Indoor Air
In the study NASA and Associated Landscape Contractors of America tested primarily for three chemicals: Formaldehyde, Benzene, and Trichloroethylene. Formaldehyde is used in many building materials including particle board and foam insulations. Additionally, many cleaning products contain this chemical. Benzene is a common solvent found in oils and paints. Trichloroethylene is used in paints, adhesives, inks, and varnishes.
While NASA found that some of the plants were better than others for absorbing these common pollutants, all of the plants had properties that were useful in improving overall indoor air quality.
NASA also noted that some plants are better than others in treating certain chemicals.
For example, English ivy, gerbera daisies, pot mums, peace lily, bamboo palm, and Mother-in-law’s Tongue were found to be the best plants for treating air contaminated with Benzene. The peace lily, gerbera daisy, and bamboo palm were very effective in treating Trichloroethylene.
Additionally, NASA found that the bamboo palm, Mother-in-law’s tongue, dracaena warneckei, peace lily, dracaena marginata, golden pathos, and green spider plant worked well for filtering Formaldehyde.
After conducting the study, NASA and ALCA came up with a list of the most effective plants for treating indoor air pollution.
The recommended plants can be found below. Note that all the plants in the list are easily available from your local nursery.
1. Philodendron scandens `oxycardium’, heartleaf philodendron
2. Philodendron domesticum, elephant ear philodendron
3. Dracaena fragrans `Massangeana’, cornstalk dracaena
4. Hedera helix, English ivy
5. Chlorophytum comosum, spider plant
6. Dracaena deremensis `Janet Craig’, Janet Craig dracaena
7. Dracaena deremensis `Warneckii’, Warneck dracaena
8. Ficus benjamina, weeping fig
9. Epipiremnum aureum, golden pothos
10. Spathiphyllum `Mauna Loa’, peace lily
11. Philodendron selloum, selloum philodendron
12. Aglaonema modestum, Chinese evergreen
13. Chamaedorea sefritzii, bamboo or reed palm
14. Sansevieria trifasciata, snake plant
15. Dracaena marginata , red-edged dracaena
For an average home of under 2,000 square feet, the study recommends using at least fifteen samples of a good variety of these common houseplants to help improve air quality. They also recommend that the plants be grown in six inch containers or larger.
In addition to counteracting off-gassing chemicals, plants improve indoor environmental quality by balancing humidity too. One plant will help purify air for about 10 square yards of living area, so the average living room might only need three or four to gain a benefit. In this case, more is probably better, but like all living things, plants need nurturing and care. As plants do accumulate dust, for the maximum environmental benefit, dust them to keep the pores in their leaves open for air intake and outflow.
Here is a list of resources for more information on this study:
PDF files of the NASA studies related to plants and air quality: http://ntrs.nasa.gov/archive/nasa/ssctrs.ssc.nasa.gov/foliage_air/foliage_air.pdf
List of NASA studies related to treating a variety of air and waterborne pollutants with plants:
“Plants take substances out of the air through the tiny openings in their leaves, but research in our laboratories has determined that plant leaves, roots and soil bacteria are all important in removing trace levels of toxic vapors.” So I guess this means I have to dust……
I found the below list with growing recommendations from the GreenLady. More from her blog post can be found here.
In a “Ted Talk” presentation. He recommends the first three plants highlighted in red below. In the studies performed by researchers at an Indian University, these were the highest performers. Meattle claims they are the only plants needed to purify indoor air completely. In his presentation he gives exact numbers and heights of plants and in which rooms to place them.
1. Areca palm: This is beautiful but takes a little more care than some people want to devote. It likes to be 5 to 8 feet from the window to receive filtered, indirect light. It hates the salts often used to soften water, so you may want to get a counter-top water purifier. It will need a little pruning, but make sure to prune only dead fronds as if you cut off brown tips, that will stop growth in that frond. The palm should also be put outside every three or four months to keep it healthy. It does become less attractive as it ages, but don’t we all?
2. Money Plant: In the Chinese culture the five-leaf money tree plant is said to bring good luck. Money trees like higher humidity than is generally found indoors, so placing the pot above a tray with water and pebbles will allow the water to evaporate around the plant. (Don’t let the pot sit in water, however!) In the growing season, the plant’s soil should be damp, but during winter when the plant is slightly dormant, you can let the soil dry out more between waterings. Don’t let its roots get soggy or leaves will start to drop off from over-watering. Pruning the plant on top will encourage a bushier, shorter plant. The leaves are critical to air cleansing and pruning encourages lots of them.
3. Mother-in-Law’s Tongue: This plant can be differentiated from the snakeskin plant by noting the yellow border as opposed to the snake’s yellow banded leaves. It is almost impossible to kill, as it tolerates light to dark and uneven watering behavior. Of course, never watering or always soaking it will do it in eventually, but it will still take time. This plant has a very nice upright architectural form with leaves that can grow to three or four feet. If you pot it in sandier soil and fertilize with a cacti formula only during the growing season, it will do extremely well.
Reed, Parlor and Bamboo Palms: These three palms can tolerate very low light, but they are happier in warmer temperatures as they are draft and cold intolerant. The Parlor palm stays the shortest, but if you don’t mind a tall plant, any of them will do. Live in the cloudy, rainy Northwest or Minnesota with a dark, winter climate? Pick another plant.
Dwarf/Pygmy Palm: This tree is slow-growing, but it can reach 10 feet tall. It is exceptionally good at removing xylene. If you give it a little summer vacation outside, you may even get some small dates. If you live in a hot apartment it will need lots of water, however. Fertilize it during the growing season and it will always look its best. Oh, it hates to get chilled, so please don’t put it near an entryway where it might get a cold blast of air.
Boston fern: These ferns have always been one of my favorites as they are so fluffy and elegant. Boston ferns love high humidity, so if you don’t want to put the planter on top of pebbles in a water dish or mist it twice a week, keep it in the bathroom. Keep the soil damp or you will always be picking up little dropped leaves that have yellowed and fallen off.
Dracaenas: There are about 40 varieties of dracaenas, but the one most familiar to people is called the “corn” plant. (Its appearance is reminiscent of how corn leaves form on a stalk.) NASA’s Clean Air Study showed dracaenas helped remove formaldehyde, making them one of the best plants to have in any home with off-gassing materials.
English ivy: Although this is a good formaldehyde, benzene, toluene, xylene and trichloroethylene remover, it is poisonous to both humans and pets. Certainly this can be a lovely plant for adults, but if you are introducing a puppy or toddler to your home it’s not worth the risk. Also, ivy doesn’t like acidic water, so if you harvest rainwater for indoor plant watering, you may have trouble with it. Go on vacation with this plant and it will probably be alive when you return. It can survive a bit of dryness but never wet feet.
Australian sword fern: If you live in the south, you do not want to let this plant outside, as it spreads like crazy there. Indoors it is one of the ferns that loves bright light and prefers a west-facing or bright east window. If your home is overly warm, don’t hang this fern from the ceiling or it will require much heavier watering. (Heat rises.) Anything up to 75°F and it will flourish as long as you water it a few times a week.
Peace Lily: These plants sprout an occasional lovely white lily if they are cared for year-round. They prefer medium to low light like that from a north window. Humidity needs to be addressed too, as if they start losing leaves they are not getting enough. They should be fertilized year-round, as they do not go dormant in the winter like many other plants.
Rubber Plant: If you have a problem with latex, this plant literally bleeds it and should be avoided! If not, it is a resilient specimen that can live in low light conditions and should be allowed to dry out between waterings. Why? Over-watering is the one sure way to kill it.
Weeping Fig: This is more commonly known as a ‘ficus’ with many hybrid varieties from which to choose. They need half a day of daylight and can be finicky if stressed or moved from one location to another. If they are near a wall they should be turned frequently for their inner foliage to stay full. A new plant might enjoy some earth worm castings, and you must remember to fertilize them. Watering weekly usually works, but if you let more than the top two inches of soil dry out, your ficus will not do very well and begin to drop its leaves.