The Environmental Impact of Indoor Plants
Power to the Peeples is an exclusive Earth911 series written by Bob Peeples, our resident chemical engineer and Program Manager of Earth911’s sister site Beaches911. Bob combines his extensive knowledge of the environment and how things work with an off-the-cuff sense of humor.
Did you know there’s a science called “environmental ergonomics?” It’s the study of the effects of ambient conditions on human comfort. The reason I bring it up is that winter is a great time to embrace indoor plants, and you may not be aware of some of the environmental benefits of this flora.
Let’s first tackle the myth that plants take in carbon dioxide and release oxygen and this cancels out animal respiration. In reality, plants sequester carbon through photosynthesis, which only takes place during the day (if we’re not breathing at night, someone explain snoring to me). Plants also “breathe” in oxygen like us day and night, but take in carbon at much higher volumes.
The other trick is that most of the stored carbon is eventually released when the plant decomposes, or if it’s burned or consumed by eating it. So, the only way to keep the carbon sequestered is to keep the plant alive and unharmed.
Air Quality Impact
Studies show improved indoor air quality when plants are present, but I don’t think this is an oxygen thing. There can’t be that much net change in oxygen or carbon dioxide, especially since our HVAC systems are designed to exchange indoor air with what is outside.
What I’d like to focus on is “phytoremediation,” or using plants to remove and retain toxins. This is where toxins like carbon monoxide, some volatile organic compounds (VOCs) or even cyanide might be absorbed and converted by the plant, while heavy metals are absorbed and retained in the plant.
Indoor plants can be great at absorbing VOCs from paint or cleaning supplies so you aren’t inhaling them.
Noise Reduction?
I have seen studies of reduced noise with plants but, if we’re talking about an office environment, wouldn’t you have to grow a virtual forest on the top of your cube? That way you could ask, “If a guy makes an inappropriate comment in a forest, and nobody can hear it, is he guilty of harassment?” (We don’t recommend you test this theory.)
Pollen Preventers
Speaking of forests, plants contribute humidity to the air because every drop of water that goes to a plant is “transpired,” meaning water moves through a plant from the roots through its vascular system to the atmosphere. The optimal relative humidity range is about 30 to 60 percent, so every little bit helps.
Humidity also reduces airborne contaminants like dust and pollen, because moisture in the air weighs down these tiny specks. The irony here is that outdoor plants may contribute to your allergies, while indoor plants can help fight them.
Business Impact
So what about your workplace and the presence of plants? Well, human assets are the most valuable (and expensive) assets of any company, usually by about 10 times the amount other business assets. Hence, any way that a business can increase personal productivity, the business wins.
The most cited studies are by Dr. Virginia Lohr of Washington State University and by Dr. Roger Ulrich of Texas A&M University. Both authors have repeatedly found increased productivity, reduced headaches/fatigue and less stress in office environments with plants.
Now That the Seed is Planted . . .
So, I don’t know how much healthier you are when you have indoor plants, but I would agree that there is at least a psychosomatic effect (mind-induced effects on the body). Plants can have a positive effect on the perception of your office and incorporate a personal touch, helping you feel more comfortable and at home.
- Lohr, V., et al. "Interior Plants May Improve Worker Productivity and Reduce Stress in a Windowless Environment" Dept of Horticulture and Landscape Arcitecture Washington State University, Pullman, WA .
- Ulrich, R.S. et al. "Influences of Passive Experiences With Plants on Individual Well-Being and Health in Human Benefits of Plants" (Relf, D. ed) Portland, OR p 93-105.
Henry Stanton
posted on November 21st, 2008 at 5:07 am
I am not sure I’m clear what you are trying to refute above – that plants release Oxygen during respiration or that plant respiration “cancels out” animal respiration.
But, it’s basic Biology that photosynthesis takes 6 molecules of Carbon Dioxide and 6 molecules of water and creates one molecule of sugar and six molecules of Oxygen.
Oxygen is released during the process and animals breath the Oxygen. And, that Oxygen is surely beneficial to an animal breather.
Some studies show that a collection of plants may increase the relative humidity in a room and reduce the over-all particulate matter (dust) both of which appear to beneficial to human health.
liyuukoo
posted on November 22nd, 2008 at 11:33 am
I am posting now from Shanghai,China,i am keeping a green leaves plant in my room,very day i feel delighted seeing it grow well and it’s fresh color.that’s the most significant of plants to me.hope hear your comments…..
Bob Peeples, PE
posted on November 22nd, 2008 at 1:01 pm
There are three important processes that need to be defined:
Transpiration is where water is moved from the soil and released through the stoma (pores at the bottom of the leaves, usually). It works like an evaporative cooler in the summer, and you can see this through the temperature drop when you drive through something like a cornfield on a summer evening. That’s the humidity thing, too.
Photosynthesis is exactly as you described but only occurs in direct light.
Respiration occurs in plants and animals both, but this occurs all of the time – day or night. Once you balance the respiration with the photosynthesis, the net numbers aren’t nearly as impressive. That’s pretty much the myth I was trying to bust. After dusk, plants are putting out carbon dioxide just like we are, but the net gain is slightly positive.
Bob
Missie
posted on December 26th, 2008 at 12:21 pm
I love my plants! Right now I’ve got seven plants in my cubicle, two of them had to go home for transplanting but will be back in the spring to make nine! :-) I’ve got approximately 40 plants in my living room (the best light) and then a few in the rest of the rooms. I just love them! Ferns are my absolute favorite!
Barry
posted on January 19th, 2009 at 1:22 pm
Hi,
I have a small concern that my many trees and plants are adding C02 into my home at night while we sleep. Is this any reason for concern?
Barry
Bob Peeples, PE
posted on January 20th, 2009 at 11:26 am
There is actually a small net absorption of carbon dioxide in the processes of respiration and photosynthesis used by plants. They do not add any carbon dioxide, but there is a common misconception that they do not respire. That is all that I was trying to point out.
Bob