Interior Plants - We are What We Breathe

Recently, someone I know in Portland Oregon emailed me about his involvement in permaculture and he is interested in learning which plants are best, for cleaning the air inside his home. Since we spend the majority of our lives, in interior environments, shouldn't the air we breathe, be the cleanest possible?

People are very conscious of the water they drink, look at the billion-dollar bottled water and home filtration industry. We are buying more organic foods every year because people are concerned about what they ingest, and how their foods are produced. If we don't eat correctly, we get sick, seriously sick and we can see the results in our friends who are overweight, or who may have diabetes or other ailments brought on by improper eating. Since we spend 90% of our time indoors, why aren't we looking at the indoor air we breathe?

As far as outdoor air, it does get some attention, and legislation is passed to limit tailpipe pollution, and the pollution emitted by factories and power plants. Living in Los Angeles, we see a diminishing of the air pollution of 30 years ago, but we are shocked at times, flying into LAX, especially in the summer, and seeing such a thick blanket of fog laying over our beloved city. We have been accustomed to air pollution and we don't speak out as much as we should. Like many Americans, we feel disempowered from the political process and have realized that smog is a political football, and we feel unable to make much of a change. We hope that our politicians care enough about our welfare to enact legislation to clean our air.

Where we do have control over the air we breathe is in our homes. I would suggest where we work, but if you work in an office, and it is one of many in an office building, you are exchanging air with the whole building, and any difference you make in your suite, is compromised by the less clean air of the rest of the building. The EPA currently ranks indoor air pollution as a significant threat to human health.

What is indoor air pollution, and where does it come from? It has many sources, such as radon gas, being emitted from the earth below your home. It could be tobacco smoke, mold, pollen, carbon monoxide, formaldehyde, volatile organic compounds, fabric softeners, benzene, trichloroethylene, toluene, and many more. Many of those with chemical names are emitted by building materials installed in our homes, such as carpets, cabinets, paneling, flooring, and all laminates. Anything made with synthetic compounds, or coated with one, can out-gas, meaning it will continue to emit toxins into our air, over months or years. In modern structures, where there is attention to insulation and sealing up structures, to conserve energy, we are finding a buildup of these pollutants. Your older drafty house may have less air pollution. What is also overlooked is the need for humidity to be between 35 and 65 percent, for optimum healthy indoor air. Air dries out in the winter, from heating systems. This low humidity contributes to respiratory problems.

We don't need to be told that our indoor air is polluted because many of us have experienced burning eyes, throat or respiratory irritations from entering fabric, furniture, or carpeting stores - we can smell the VOCs and formaldehyde that has out-gassed from their products. Often our exposure to these chemicals begins when as newborns, we are brought home from the hospital and are placed in a room that was freshly painted, and has new furniture, carpet, blankets, pillows, toys, etc. These products and paints are emitting VOCs, formaldehyde, toluene and other pollutants. Perhaps these chemicals bring on early childhood allergies and asthma.

A solution to the indoor pollution problem found in homes and offices is the use of indoor plants. NASA has been researching this problem, knowing that in the space stations they are planning, clean air is paramount. They found that many common indoor houseplants and potted blooming plants offer an ability to filter out these pollutants and provide needed oxygen.

This process of filtering pollutants from the air is as follows: Plants release water vapor from their leaves, which is called transpiration. As this vapor is released, it stimulates the movement of air and through temperature differences between the surrounding air, and the leaf surfaces, convection currents cause airflow, some of which are pulled down through the soil, to the root zone. In this area, pollutants are broken down, into a source of energy for the plant. Through stomata in the leaves (small openings), plants translocate the volatile chemicals down to the root zone, to