Portrait of a girl posing on a sofa in a living room with green plants.

by Paul Fassa
Health Impact News

Your indoor air should be cleaner than outdoors, unless you live in a remote, pristine, heavily-wooded or coastline area. But for most of us, that’s not the case. And most of us spend much more time indoors than outdoors thinking we’re safe from the pollution of vehicular traffic, aircraft aerosol spraying, and industrial pollution.

Most people don’t think in terms of indoor pollution. But due to modern construction and insulation materials demanded for better energy conservation, chemically-laced furnishing and carpeting, stored toxic cleaning materials, and other particulates brought indoors into dwellings that are airtight, recycled air for cooling and heating tends to accumulate an invisible cloud of toxic pollution indoors.

The toxic chemicals “off-gas” or release their vapors into indoor environments that are poorly ventilated with fresh air. In addition to chemical and particulate pollution, oxygen is diminished by the necessary practice of breathing without outdoor air circulating. 

The air inside your home or office can be worse than outside air. Since most of us spend the bulk of our time indoors, it would be wise to ensure our inside air is as healthy as possible. 

The amount and extent of indoor air toxins are surprisingly high. But there are ways of purifying your indoor air and protecting against those indoor airborne toxins.

NASA Research Project Studies Indoor Plants to Absorb Toxins

Tropical philodendron with big leaves on table indoors photo

Tropical philodendron with big leaves.

The research was designed to determine what indoor plants had the ability to absorb off-gassed toxins, known as volatile organic compounds (VOCs) while converting carbon dioxide to oxygen by photosynthesis with normal indoor lighting.

After conducting a two year indoor plant study, published in 1989, with the consideration of what would be appropriate for future space stations, NASA (National Aeronautics and Space Administration) and ALCA (Associated Landscape Contractors of America) came up with a list of effective plants for treating indoor air pollution that could be used in living quarters and office buildings. 

Here is a list of what was researched with positive findings, but it was compiled a few decades ago. There could be others added to this list. In addition to recycling carbon dioxide from mammalian breathing, they remove airborne toxins such as benzene, formaldehyde, and trichloroethylene from airtight indoor spaces. 

It’s recommended that fifteen or more plants in medium sized pots be distributed into a 1500 to 2000 foot living area or one plant for every 100 square feet. This list offers several natural indoor air pollution solution options.

  • Philodendron scandens ‘oxycardium’, heartleaf philodendron 
  • Philodendron domesticum, elephant ear philodendron 
  • Dracaena fragrans ‘Massangeana’, cornstalk dracaena 
  • Hedera helix, English ivy 
  • Chlorophytum comosum, spider plant 
  • Dracaena deremensis ‘Janet Craig’, Janet Craig dracaena 
  • Dracaena deremensis ‘Warneckii’, Warneck dracaena 
  • Ficus benjamina, weeping fig 
  • Epipiremnum aureum, golden pothos 
  • Spathiphyllum ‘Mauna Loa’, peace lily 
  • Philodendron selloum, selloum philodendron 
  • Aglaonema modestum, Chinese evergreen 
  • Chamaedorea sefritzii, bamboo or reed palm 
  • Sansevieria trifasciata, snake plant 
  • Dracaena marginata , red-edged dracaena   

The potting soil’s microorganisms do most of the scrubbing of VOCs taken in from the plants’ cycle of “breathing” in carbon dioxide and “exhaling” oxygen. Despite the word organic, VOCs refer to toxic gases that vaporize from liquid and solid matter, sometimes even at temperatures below freezing. With warmer temperatures, VOCs expand even more to fill indoor spaces.  

Dwelling Indoor VOC Sources

Almost all commercial, non-organic cleaning products; fireproofing chemicals for blankets, mattresses, and carpeting; paints and thinners; dry-cleaned clothing; insecticides; petroleum-based flooring and the glue used to hold it down; along with some indoor plastic items off-gas VOCs.

More ubiquitous in modern construction are the glues that hold pressboard and particleboard together. They are both used in modern home construction and furnishings. Pressboard and particleboard materials are cheaper than whole wood. But the glues that are used to hold them together emit toxic VOCs. 

If you drive by an area where new homes are being built, you may notice particle board panels used for base walling and flooring within solid wood framing. Indoor fixtures may contain pressboard panels. Occupants are surrounded with VOC-emitting materials. This is the way things are now. Cheap toxic materials for building homes and low rise office spaces that sell for high prices.  

Although removing known toxic items and substituting them with safer products will reduce a dwelling’s toxic VOC load, the only thing one can do to diminish the structure’s inherent toxicity would be to implement constant air purification using the right plants placed throughout or mechanical air purification devices discussed later in this article. 

NASA also observed that some plants are better than others for treating certain chemicals. For example, English ivy, gerbera daisies, pot mums, peace lily, bamboo palm, and Mother-in-law’s Tongue were found to be the best plants for treating air contaminated with benzene. 

The peace lily, gerbera daisy, and bamboo palm were very effective in treating trichloroethylene.

Additionally, NASA found that the bamboo palm, Mother-in-law’s tongue, dracaena warneckei, peace lily, dracaena marginata, golden pathos, and green spider plant worked well for filtering formaldehyde.

A more comprehensive graphic of illustrated plants, which chemicals they absorb, with some information on human adverse reactions from those chemicals and the materials that off-gas them can be accessed here.

Other Mechanical Methods of Purifying Indoor Air 

In addition to distributing potted indoor plants in dwellings and indoor workplaces, Dr. Bill Wolverton, the lead researcher with the NASA indoor air project suggests:

Combining nature with technology can increase the effectiveness of plants in removing air pollutants. A living air cleaner is created by combining activated carbon and a fan with a potted plant. The roots of the plant grow right in the carbon and slowly degrade the chemicals absorbed there. (Source)

Today’s technology has created several mechanical indoor air purifiers that can be used alone or in conjunction with plants. Keep in mind plants do more than purify the air. They replenish oxygen while absorbing carbon dioxide.

The most efficient electrically-run or artificial air filters contain more than one type of filter. But the most essential filter, according to those knowledgeable, is a HEPA filter. This acronym stands for “high-efficiency particulate air” with the “A” sometimes taken as “absorber” or “arresting”.  

You can peruse several product options to determine which would fit your budget and accommodate your indoor environment’s needs on this page. 

Note: There is a tendency to exaggerate ozone “dangers” that some machines may produce. This tendency probably stems, at least partially, from high ozone air quality atmospheric danger reports from the media. 

But ozone or O3 is mixed with pollutants when it’s trying to neutralize to eliminate smog. The added oxygen molecule of O3 is unstable enough to contribute to bond with many toxic elements and neutralize them. 

That vaguely pleasant scent and clean air sensation around or on the sea and during mild thunderstorms is ozone. If too much occurs within a small airtight space, those heavier O3 molecules may create breathing difficulties. But ionizers in air filters can be shut off if that’s beginning to occur.   

What About Mold?

The extreme health hazards of mold are best handled by experts who specialize in removing it. Damp spots can create black mold. Their spores get into the indoor air and create some serious sometimes chronic ailments. Removing black mold takes a few days of intensive cleaning and ventilating. 

If you’re renting, notify the manager or landlord upon spotting black mold in currently or once damp areas. Get it confirmed as toxic black mold and demand its cleaning. Most local laws support this dynamic. When buying a home, have it inspected for mold. The seller is responsible for covering that expense.