Most any homeowner has heard it at one time or another: Houseplants can do a world of good beyond just sprucing up a house’s interior. In fact, houseplants have been found to be an efficient air cleaner to combat indoor air pollution.

In 1989, NASA conducted a study testing a range of houseplants for their ability to filter three chemicals — benzyne, formaldehyde and trichloroethylene — that are pollutants commonly found in home (much of which comes from the use of synthetics in common household items such as computers and carpeting).

The results of the NASA study were that in the small, closed spaces the plants were able to convert about 65 percent of the gasses and transform them into oxygen. The plants do this using photosynthesis — that term we all learned in school — to snatch gasses from the air with their leaves, absorb the toxins into the root systems, and transform the gasses back into oxygen.

“To me, that is an amazing story,” Michael Hull, a horticulturist and owner of Evergreen Plantscapes in Bend, said of the NASA findings. “It just goes to show how effective (the plants) are.”

What that means for homeowners is that the right houseplants under the proper conditions can make nifty air filters for those long winter months in Central Oregon when the windows are closed and the fresh air is strictly outdoors.

Plants can also act as a natural humidifier, which can come in handy here in the high desert.

Of course, for the houseplants to be effective there must be enough in a home to make a difference. About one potted houseplant per 100 square feet was needed to make a significant impact in the NASA study.

And most importantly, the plants must be in good health, Hull said. As a general rule of thumb plants can be damaged by low-grade soil, soil that is too moist (which can foster fungal spores) or too dry, or if houseplants are not kept between 65 degrees and 90 degrees.

“All of these things can prevent plants from operating efficiently,” said Hull, adding that contaminated soil can reverse the positive effects of photosynthesis by putting toxins back into the air.

“That’s why plant care is so important,” Hull added. “If a plant is healthy, then it is going to be doing a good job. If the plant is unhealthy, then it can be more of a detriment.”

It is also important to note that houseplants can be extremely detrimental to the health of pets and children if they are ingested, especially in large amounts. Many are considered toxic and can cause severe illness, so arranging the plants so they are out of reach of nibbling pets and curious toddlers is the best option.

With these considerations in mind, here are some plants that Hull suggests could help combat indoor air pollution that are all available in Central Oregon: