According to the EPA, indoor air quality is 3-5x worse than outdoor air. And the ultimate in indoor air is that of a space station -- ventilation simply isn't possible. This is partly why NASA researchers set about determining the best way to cleanse the air in space stations. Is it a machine? A certain humidifier?

No: It turns out to be plain old houseplants.

The head of the NASA research was Dr. B.C. Wolverton, who said, "plants emit water vapor that creates a pumping action to pull contaminated air down around a plant's roots, where it is then converted into food for the plant."

In other words, what's toxic for us is food for them. They remove chemicals like benzene, formaldehyde, trichloroethylene, ammonia -- chemicals that have been linked to minor health effects like headaches and eye irritation as well as major ones like asthma and cancer. Plus, plants then emit oxygen, which further improves our air.

NASA advises keeping at least one plant for every 100 square feet of home or office space. Here are the top 10 suggested plants:

1. Spider Plant

If you have dust allergies, this is the plant for you. In two days, a spider plant can eliminate close to 90 percent of toxins in a room. Its leaves absorb both mold and other allergens (including dust), and it has also been shown to absorb carbon monoxide and formaldehyde. Bonus: It's easy to grow and hard to kill.

2. Peace Lily

The Peace Lily is more than just pretty -- it can improve indoor air quality by up to 60 percent. It also reduces levels of mold by absorbing spores into its leaves, then down to its roots for food. The Peace Lily also ingests acetone vapors and can keep bathrooms free of mildew (including on tiles and shower curtains).

3. English Ivy

This is good for the office: Research shows that having English Ivy on your desk helps you focus, since it absorbs benzene, a chemical common in office supplies and appliances. English Ivy is also great for homes with pets -- it lowers levels of fecal matter in the air.

4. Boston Fern

Boston ferns are excellent for those with dry skin, since they act as natural air humidifiers. They also lower levels of formaldehyde, which is found in glues as well as cabinetry and some furniture. Gardeners, take note: Boston ferns also help remove toxic metals like mercury and arsenic from soil.

5. Heart Leaf Philodendron

The heart leaf philodendron is one of the most effective plants at removing formaldehyde as well as carbon monoxide from the air. However, it's actually toxic to consume, so best to keep it up and out of sight in homes with kids and pets.

6. Eucalyptus

Good for the bedroom, Eucalyptus emits a refreshing minty fresh scent that's more than just nice to smell -- it soothes your respiratory tract. By gently opening nasal passages, it aids in breathing. It also kills airborne germs, keeping your office or home safe and healthy.

7. Aloe Vera

Aloe does more than heal cuts and burns. It helps keep your home or office free of benzene, a toxin often found in paints and chemical cleaners. It's also handy to have on hand in the summertime, since it can soothe your skin if you get a sunburn.

8. African Violets

Simply looking at the purple of African Violets has been shown to benefit one's health. Gazing at it helps stimulate the release of a small amount of adrenaline, which raises energy levels, and increases the flow of oxygen to your brain, which helps you relax. Bonus: They grow well in artificial light, making them perfect for the office.

9. Chinese Evergreen

The Chinese Evergreen's tiny red berries help eliminate toxins frequently found in chemically-based household cleaners. Plus, the longer you keep the plant around, the more toxins it removes. You're not the only one who improves with age.

10. Chrysanthemums (Mums)

Mums are both beautiful and beneficial. They absorb benzene, found in plastics, paints, and detergents. They're also exceedingly cheerful to look at.

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Plants are an elegant solution to the ubiquitous nature of the chemicals found in nearly all homes and offices. Green up your environment and green up your lungs. Your health will thank you. 

Published on: Jun 24, 2016
The opinions expressed here by Inc.com columnists are their own, not those of Inc.com.