ZZ Plants (Zamioculcas Zamiifolia) have a lot going for them. They have beautiful foliage. They can grow to a massive size, and they take very little maintenance. On top of all of those perks, you may be asking what else can they do?
Can ZZ Plants purify the air? Experts are still undecided on whether or not house plants truly purify the air. There have been studies that show houseplants do remove toxins in the air that cause allergies and sickness, but still many believe that there is not enough research to support this claim.
There are strong arguments to be made on both sides of this debate, as well as research from some very reputable organizations. In this article I’ll give you the arguments from both sides as well added information on ZZ Plants specifically.
The Problem: Air Quality
It is no surprise that people want to improve the air quality in their homes. With chemicals, carpets, pollen, and dust, the quality of indoor air has long been a concern. And nearly everyone has heard it said that plants can eliminate day-to-day pollution by filtering the air we breathe.
It is common knowledge that poor air quality can cause serious illnesses, like lung disease, asthma, and cancer, so it’s understandable that plant lovers would hope their plants have purifying qualities. For decades, scientists have tried to provide definite proof of this theory and have uncovered fascinating information.
We know that plants absorb carbon dioxide and release oxygen back into the air as well as add humidity to the rooms of your home that they are grouped in. But while they can certainly up the oxygen, can they truly purify the room?
The Research
Several studies have been conducted showing positive effects on air quality from houseplants. The most famous of which was run by NASA in the late 80s. In partnership with the Associated Landscape Contractors of America, NASA created a project called the Clean Air Study to help them determine methods of filtering and purify the air in space stations.
They found that some house plants really were able to remove cancer-causing toxins like benzyne, formaldehyde, and ammonia from the air. Plants with large leaves were found to be the most effective as there seems to be a relationship between leaf surface area and the amount of toxins that were absorbed by the plant.
Since 1989 there have been several other studies suggesting that indoor plants do have the ability to improve the air quality in spaces, including one that suggest that the microorganisms found in potting soil remove benzene from air.
But the jury is still out. Many people suggest that these studies merely prove that in a small, controlled and sealed environment that indoor plants can make these improvements, doubting the ability to make a real difference in our homes.
The Doubts
In the NASA Clean Air Study, NASA was specifically looking for ways to purify the air in space stations. These stations would be small and completely sealed off. They also exposed their plants to the maximum amount of light to ensure the highest efficiency in photosynthesis.
This laboratory setting differs greatly from most of our homes, where constant opening doors and windows, as well as large HVAC systems turn the air over about once every hour.
While some of us may be lucky to have sunrooms or other spaces with maximum light for our houseplants, the majority of apartments and houses have barely enough light for a plant to photosynthesize.
Because of these major discrepancies, many scientists today believe that houseplants will not have the same air purifying effect in an average home as it did in the NASA experiment in 1989.
Even if we do believe the findings from this NASA study would hold true in our homes, there is another factor at play: quantity of plants. In his book about the subject, scientist Bill Wolverton suggests that for purification you would need at least two large plants per one hundred square feet to yield the same results.
That would mean you would need approximately twenty large houseplants to filter the air in a one thousand square foot home. While it may be possible to squeeze that many plants in, for most people it is not realistic.
More often than not, people may have a few small houseplants in their large home. While there are other health benefits to consider from bringing nature indoors, it is doubtful that these few plants are making any real substantial difference in the air quality around them.
What About ZZ Plants Specifically? Do They Filter Air?
ZZ Plants (Zamioculcas Zamiifolia) were not in the original set of plants that NASA tested in 1989. However, they do seem to meet the standards which would suggest that they would remove toxins in the NASA laboratory setting.
ZZs can grow to be three to five feet in height and are full of bright green leaves. Plus, they only need a low amount of light to photosynthesize. These factors all point to the fact that ZZs do purify air in controlled environments.
Other Health Benefits Of Owning Houseplants
So maybe houseplants aren’t able to keep up with the constant turnover of air in our homes, but does that mean there are no health benefits to having them? Certainly not!
Most people know that plants release oxygen into the air, but they may not know that plants also increase the humidity level in the area surrounding them. Increased humidity levels help with cracking skin and lips as well as dry noses and throats and generally makes our homes feel much more comfortable.
Mental health also seems to get a major boost from houseplants. There have been a number of studies which show that bringing nature indoors can increase productivity and memory retention, reduce stress levels, and decrease recovery time after medical procedures.
Do ZZs Give Off Oxygen At Night
Plants use CO2, water and sunlight to create food for themselves and release oxygen into the air. At night, when there is no light to be absorbed, most plants stop their photosynthesis processes, reducing the amount of oxygen released. Some plants, however, do the opposite.
Plants that are native to extremely arid environments keep their pores closed during the day to reduce the amount of moisture they lose in the hot sun. This means that those same plants open up to absorb carbon dioxide and release oxygen during the night.
ZZ Plants do not release oxygen at night, but rather during the day like most other houseplants. If you’re looking for a plant that does give off oxygen at night consider adding Snake Plants, Areca Palms and Orchids to your space.
Are ZZ Plants Toxic?
Now that we’ve discussed what plants add and remove from their surroundings, we need to address a myth surrounding ZZ Plants. Several years ago a rumor started circulating that ZZ Plants release cancer causing toxins into the air. This is not true and has not been cited in any study or experiment.
ZZ Plants are, however, considered to be toxic, although the effects they have on humans and animals is more in line with an upset stomach than any more serious or long-lasting illness.
The sap inside a ZZ contains a compound called calcium oxalate. While this compound isn’t necessarily considered toxic on its own, if you looked at it under a microscope, you would see it’s made up of tiny crystals. These crystals tend to have sharp, jagged edges that can irritate skin or soft tissues when they come into contact with it.
ZZ Plant produces calcium oxalate in all parts of its plant structure (leaves, stems, roots, and rhizomes). Because of that, contact or ingestion of any part of it could potentially cause discomfort. For more information on ZZ toxicity, read this article.
Where To Place Your ZZ Plant in Your Home
One of the reasons that ZZs are loved by so many is that not only are they extremely easy to care for, but they can reside in almost any type of light. While some plants need full sun, or bright indirect light, ZZs can be happy just about anywhere.
When it comes to placing a ZZ in your home, really any spot will do. Whether you want it in your bright and sunny kitchen or in a dark and humid bathroom, ZZs can survive almost anywhere.
You should note that while they can live in most light conditions, they will grow faster in others. Areas with bright, indirect light, such as near (but not directly against) sunny, south-facing windows will yield the quickest growth for your plant.
The Verdict
Personally, I lean to the side stating that there is not enough research to support houseplants making a substantial difference in air quality in the average home. That being said, I still love them! And my house is absolutely full of plants. Even though they don’t necessarily purify the air around us, there are physical and mental health benefits from bringing the outdoors indoors, and I say the more the merrier!