You may remember learning in school about the reciprocal relationship animals (including us) have with plants. We inhale oxygen and exhale CO2 (carbon dioxide.) Plants “inhale” carbon dioxide and send out oxygen. That means we need plants as much as they need us.

But plants do even more for us than create oxygen. They can actually purify the air.

That’s good news, especially these days. Because modern living puts an extraordinary amount of toxins into our homes, and these toxins can lead to long-term brain damage.

If you choose the right houseplants, they can be a practical indoor air filter. Here’s the full story. . .

“New Car Smell”

If you’ve ever sat in a new car, chances are you noticed the “new car smell.” Many people like it, although I’m not one of them.

The new car smell comes from VOCs (volatile organic compounds) that are released from the materials the car is made from, such as molded plastic, adhesives and sealers.  The smell fades over time, but that doesn’t mean VOCs aren’t still present.

The same is true for your home.  Unless the builder carefully selected building materials and paints that don’t “outgas,” then the ones used to make your home probably give off VOCs. Possible culprits include everything from the lumber used, to the paint on your walls, and all your furniture, carpeting, and drapes.

Electronic devices are among the worst offenders – televisions, desktop computers.  (Apple iPads and iPhones don’t outgas, that’s one of the reasons I use them.)

We also bring VOCs into our homes in other ways. They’re in cleaning products, moth repellents and air fresheners.  Even our dry cleaning.

A study done in Michigan visited 126 homes at different times of the year to measure their levels of VOCs. Researchers were astounded to find a total of 56 different VOCs in ordinary homes.1

According to the Environmental Protection Agency (EPA), many VOCs can cause cancer. Worst offenders include benzene and formaldehyde (found in products such as paint, detergent, furniture wax) and perchloroethylene (which comes from newly dry-cleaned clothes). And there’s another reason to be concerned…

Findings from a study published by Harvard’s School of Public Health shows exposure to certain VOCs may cause irreversible brain damage.2

The study looked at 2,143 people who had careers working for a utility company.  The company records showed the workers were exposed to products containing various VOCs, including benzene.

To test their brain health, the researchers gave study participants cognitive tests about ten years after they retired. A shocking 82% of them showed cognitive impairment.

The researchers also looked at other lifestyle factors, such as education, use of tobacco and alcohol, and age. But adjusting for these factors did not change the findings about VOCs.

Nature’s Best Air Purifiers

Luckily, we can tap into the amazing power of plants to help.

You may have heard of the NASA houseplant study done about 30 years ago.  It was led by B.C. “Bill” Wolverton, a scientist for NASA. The well-documented study looked at houseplants as a possible way to purify the air in enclosed areas like office buildings (or space stations).3

The results showed many plants have an amazing ability to clear the air of certain toxins. And numerous other studies have followed. Some even show plants can target specific toxins, like mercury.

Mercury build up is a problem for shops in the Brazilian Amazon that deal in the gold trade.  But research shows certain plants, such as Spanish moss, can detect and absorb mercury from the air.4

And it turns out there are benefits to adding plants to our lives that go beyond purifying the air.

Soil has a healthy strain of bacteria called Mycobacterium vaccae. Merely breathing it in has been shown to boost our brain’s frontal lobe activity.

Plants also lower people’s physical symptoms of stress and improve their mood. This happens because simply interacting with plants suppresses a person’s autonomic nervous system.5

Which Plants are Best?

Based on Wolverton’s study, the most effective plants to remove benzene are English ivy, peace lily, marginata, and Janet Craig plant (genus Dracena). These plants removed 77.6% of benzene from the air during a 24- hour period.

What if you want to remove other VOCs, too?  Based on their overall ability to remove chemical vapors and their ease of maintenance, here are the top ten plants to consider: areca palm, lady palm, bamboo palm, rubber plant, Dracaena, English ivy, dwarf date palm, ficus, Boston fern, and peace lily.

The list appears to be heavily weighted toward tropical plants, especially palms.

The NASA study recommends about one plant for every 100 square feet of floor space. So if you have an 1,800 square foot house, you’d want about 15-18 plants.

One final note… plants do the best job purifying the air in spaces where there’s not a lot of ventilation.  But please keep in mind that it’s better for you if your environment has good ventilation.  That in itself helps remove VOCs. Either way, I still think you’ll improve your well-being by adding some plants to your living space.