I should be a lot nicer to the plant struggling along on my dining-room windowsill.

The poor, wilted thing could be improving the air quality in my home.

Research in this area is, if you will, blossoming.

Last month, Pennsylvania State University researchers published a study suggesting houseplants can cleanse indoor air of ozone.

They focused on three that are low-cost and low-maintenance - snake plant, spider plant, and a pothos like mine.

Researchers upped the ozone levels in airtight chambers to 200 parts per billion - roughly equivalent to a really bad day in a really urban area. In the control chamber with no plants, the ozone concentration took 74.8 minutes to sink to five parts per billion. The ones with plants took between 46.3 and 50.3 minutes.

A month before that, University of Georgia researchers published their study of 28 common plants. They concluded that five in particular - red ivy, English ivy, purple heart, asparagus fern, and wax plant - had "superior" ability to filter out volatile organic chemicals, including benzene, toluene, and octane.

In February, Korean researchers found that weeping fig and Fatsia japonica, an evergreen, can reduce levels of formaldehyde from smoking, gas stoves, and other sources.

This is good, because indoor air isn't all we might like it to be. The concentration of pollutants indoors often exceeds that of the outdoors, according to the Environmental Protection Agency. All our vehicles and factories and coal plants notwithstanding.

It's of particular concern, the agency notes, because studies show that people in industrialized nations (like the United States) spend upward of 90 percent of their time indoors.

That ghastly statistic aside - doesn't anyone go for walks anymore? - airborne contaminants can come from a plethora of sources.

They can come from stoves, heaters, furnaces, fireplaces, pesticides, cleaners, office equipment, building materials, paint, carpeting . . . and even your pet cat or dog, which has dander.

Not surprisingly, most exacerbate or cause lung problems and worse.

Some of the seminal work in the area of indoor plants and air pollution was begun after the 1969 moon landing.

Officials began to contemplate creating a permanent facility on the moon. And Bill Wolverton, then a NASA scientist at the Stennis Space Center in Mississippi, started studying plants in a sealed environment, as so many of our houses have become.

Many of his studies were published in the 1980s. In 1997, he published How to Grow Fresh Air: 50 Houseplants That Purify Your Home or Office. It's still available.

Penn State's Dennis Decoteau, a professor of horticulture and plant ecosystem health and one of the ozone paper's authors, says plant leaves have tiny pores, called stomata, through which they more or less inhale and exhale.

Researchers think that when a plant takes in harmful molecules - ozone, VOCs, and the like - substances in the plant attack and neutralize them. You wouldn't say a plant has an immune system, but that's the gist.

There is, as usual, some dispute. Neither the EPA nor the American Lung Association is getting on the plantwagon. Both maintain that the lab results have not been replicated in the real world.

Officials caution that damp soils around plants can breed other lung-irritating nasties, like molds. (My pothos should be so lucky.)

Instead of plants, the ALA promotes things like adequate ventilation when cooking, storing pollution sources like pesticides outside, and keeping the humidity low so you don't get dust mites.

Above all, don't smoke.

Janice E. Nolen, the ALA's assistant vice president for policy and advocacy, says houseplants are, of course, "lovely. I have them in my home. But I wouldn't look for them to be a solution to indoor air pollution."

Nonetheless, Decoteau and others think there's promise aplenty. "We're just starting the conversation," he said.

Wolverton is more adamant. He says the scientific evidence is "overwhelming."

Plants even have been shown to produce negative ions that destroy microbes and give people a euphoric feeling, he says.

He and a partner, Kozaburo Takenaka, have another book, Plants: How They Contribute to Human Health and Well-Being, due this fall.

Meanwhile, Wolverton, who is 76, keeps on growing. His house, he says, "is full of plants. It's been full of plants for 30 years."

Contact staff writer Sandy Bauers at 215-854-5147 or sbauers@phillynews.com. To post a comment, visit her blog at http://go.philly.com/green space.