Planting Seeds for Clean Air

woman watering plants by Youheum Son
Youheum Son

Plants aren’t just pretty to look at—they can actually purify the air in and around your home, and clean toxic soil, too.

Whether moving into a new building or just bringing a product home for the first time, you might smell some of that “new mattress/rug/clothes smell.” That smell might be a marker of something new and exciting, but it comes from toxic VOCs released during manufacturing. Not to fear— bring some new houseplants in to help! Plants have the incredible potential to improve your air quality. Outside, plants can improve soil health, too.

Pollution in and around your home can be a scary reality to confront, but these natural ways of reducing air and soil contamination are great steps towards reducing toxicity exposure of you, your family, your pets, and your garden. 

In a 1989 NASA study, scientists learned that when plants “inhale” CO2 and “exhale” oxygen during photosynthesis processes, they also inhale air pollutants. They purify the air by essentially scrubbing it of cancer-causing VOCs and releasing clean oxygen. Microorganisms in potting soil digest toxic chemicals. The study was intended to help scientists decide whether plants should be included in international space travel, but the results can help those of us living in regular homes and apartments back on Earth. 

Choosing Indoor Plants

When it comes to choosing plants to use as air purifiers in your home, the bigger and leafier the better—and hairy and waxy leaves are even more effective. How many you need depends on your space, based on airflow and ventilation. A stuffy TV room could have more built-up air pollutants than an airy living room, but there’s no reason more plants can’t be merrier in every room of the house. 

Remember that diversity is your friend, as different species remove different pollutants from the air. Happy plants filter air more efficiently, so consider where they’re placed to optimize the sun and temperature in your home (some plants might like to be next to an eastern window but not too close to a heat vent, for example). Read up on your plants or ask someone at a gardening store to find out about the plants you chose.

Plants for Indoor Air Quality 

Based on NASA’s study, these are some of the best plants for air purification (in no particular order):

  • Purple Waffle Plant (Hemigraphis exotica)
  • Gerber Daisy (Gerbera jamesonii)
  • Boston Fern† (Nephrolepis exaltata bostoniensis)
  • Golden pothos*† (Epipremnum aureum)
  • Bamboo palm* (Chamaedorea seifrizii)
  • Peace lily*† (Spathiphyllum) 
  • Chinese evergreen* (Aglaonema modestum) 
  • Ficus*† (Ficus benjamina) 
  • Snake Plant/ Mother in Law’s Tongue*† (Sansevieria laurentii)
  • English Ivy*† (Hedera helix)

* Toxic for pets to eat. If you have pets, remember to check the ASPCA’s Poisonous Plants list before adding plants to places where critters could get to them. 
† These are invasive species, to be kept potted and indoors only. If you ever decide to give up these plants, don’t leave them in the wild. Give the potted plant to a friend, or throw the plant and roots in the trash.

Besides helping you breathe easier, indoor plants have been shown to lower blood pressure, reduce stress, and lessen cold symptoms.   

Choosing Outdoor Plants

Amazingly, outdoor trees can reduce your indoor air pollution, too. This is because particulate matter that might enter through open windows or on the bottoms of your shoes is filtered by trees and other plants between the street and your front door.

A study from Lancaster University shows that having trees between the road and your front door can reduce indoor particulate matter by half. Just like inside, the bigger the leaf, the better at filtering the air—depending on where you live, evergreens may be preferable for year-round filtration.  

When growing anything outdoors, make sure to plant diverse species native species to your region, which need less water and inputs to thrive and reduce the proliferation of invasive species. If you’re not sure, ask at a locally owned garden store, or go to The National Wildlife Foundation’s native plant database at NWF.org/NativePlantFinder.

Trees for Outdoor Air Quality 

Common trees with the most ability to remove particulate matter:  

  • Eastern red cedar (Juniperus virginiana) 
  • Red maple (Acer rubrum) 
  • American elm (Ulmus americana)
  • White poplar (Populus alba) 

Plants in your yard or garden can work for you by drawing toxins out of the soil. You’ll know if your soil is toxic if you test it (see "Test Your Soil" below), which you should do if you have doubts about the previous uses of your yard, and always if you’re planning to grow food.

Plants absorb minerals from the soil to grow—minerals that could be toxic at large quantities, like copper, lead, nickel, and mercury. If you use plants to draw out toxicants, don’t compost them after you pull them out, which will re-disperse the minerals back into the soil. Instead, put them in the trash. 

Plants for Soil Health

  • Mustard greens/Indian Mustard (Brassica juncea)
  • Herbs in the mustard and cabbage family (look for the scientific name Brassicaceae or Cruciferae families)
  • Sunflower (Helianthus annuus)
  • Aster (Aster amellus)
  • Vetiver grass (Chrysopogon zizanioides)
  • Colonial Bentgrass (Agrostis capillaris)
  • White lupine (Lupinus albus)

If you test your soil and find that it’s in bad shape, but you still want to grow food, it’s ok to use raised beds and purchase soil. Just make sure the bag says it’s enriched with things like compost and natural materials, not chemical fertilizers. 

Test Your Soil

Most of us don’t know the full history of our homes and the land they’re on. Soil tests can identify threats and imbalances in your yard or garden and give direction on how to fix them. When you know what’s in your soil, you can grow healthier foods and build safer play spaces.   

Soil test results can identify the presence of toxic chemicals, beneficial carbon levels, pH, and nutrient levels. Healthy garden soils have the incredible potential to feed your family, beautify your community, and fight climate change.

Results will include detailed instructions on how to amend your soil, and garden stores may also be able to give recommendations if you bring in your results. Spring is a great time to test your soil, when the ground is thawed and digging won’t disturb too many plants.  

How to test your soil:  

Universities in every state offer cheap, easy at-home tests and professional scientific results. Green America’s food campaigns manager Jes Walton did a basic test plus soil carbon evaluation, which cost less than $50 and took under an hour on her part (Read Jes’ full story about how her soil test went). Find contact information for your local university soil test lab.

Labs may have testing supplies available for pickup, or they will send them to you by mail, and you can return soil samples the same way. While you can find supplies online or at local garden stores, we suggest using a local university to ensure that tests are conducted in professional labs. The scientific advice you’ll get with your results can make all the difference to a healthy yard or garden. 

Specifics on each test may differ, so be sure to read the instructions, which may ask you to collect samples from certain depths and mix soil from many test sites.  

From Green American Magazine Issue