Indoor plants can be used to reduce indoor air pollution of a certain type. There are several methods that can be used to purify the air in our homes, but the only natural and consistent way is to use indoor plants. It has been argued that air pollution can be reduced by excluding the pollutants, but how realistic is that! Extraction methods do no more than move the pollution from one place to another, but do not eliminate it – so what is the answer?
Before discussing that, it is necessary to discuss the type of pollution we are referring to. This is not dust mites, pollen, cigarette smoke or any other airborne particulates, but VOCs (volatile organic compounds) that present a very real and serious health risk. Examples of these are benzene (a carcinogenic), toluene and xylene (both paint components), and also acetone used in nail varnish remover and other organic solvents used for a wide variety of purposes, and that can get into your home. Others include tars and low molecular weight species from tobacco smoke.
The Source and Effects of Carbon Dioxide
Another indoor pollutant that many seem to ignore is carbon dioxide, which can lead to tiredness and lack of energy. Plants use carbon dioxide in their metabolism, much as we use oxygen, and then release oxygen into the atmosphere – or into your home. Nobody has ever denied that indoor plants clean air of CO2 and provide a healthier environment for you and your family.
In fact, carbon dioxide is a by-product of the cellular respiration that generates energy in every cell in your body, and indoor plants can absorb much of the carbon dioxide that you breathe out. Without them, you would have to remove the CO2 from your home in some other way – generally by extraction or through ventilation.
Plants That Clean Indoor Air
One study carried out on aldehydes and ketones has proved that the Peace Lily and Golden Pothos removed VOCs from the atmosphere. The amounts that were dissolved in the leaves of these plants were between 30-100 times less than the measured quantities removed [1]. This suggested that the leaf was metabolizing these VOCs rather than just absorbing them. The hypothesis was proved by analyzing the uptake from a sealed bag [2] when there was no other mechanism by which the levels of these VOCs could be reduced.
Although this might surprise you, the VOCs mentioned above are common household pollutants. Others include oxides of nitrogen, radon, insecticides and carbon monoxide. They originate from tobacco smoke, external exhaust fumes, cleaning materials, plastics, adhesives, paints and so forth. Even tap water contains some volatile pollutants.
In one study, a number of different plants were grown in a shade house for eight weeks, and then taken indoors for 12 weeks acclimatization prior to being put into air-tight glass jars. They were each exposed to a range of VOCs and atmospheric pollutants and the results recorded.
In this test, the four best indoor plants with highest removal rates of VOCs were the Purple Waffle plant (Hemigraphis alternate), English Ivy (Hedera helix), the variegated Wax Plant (Hoya carnosa) and Asparagus fern (Asparagus densiflorus). By introducing these plants, and others, into a room, it was conclude that it is possible to make a significant improvement in air quality.[3]
If you carry out an internet search for the best house plants for air quality, you will find a number of different results. The bamboo palm, Dracaena, rubber plant, spider plant and more are all recommended as the best indoor plants for the removal of indoor air pollution in addition to the above, although not all come with scientific evidence of their effectiveness as those listed above. It is likely that there are large numbers of houseplants that are effective in removing VOCs from the air.
How to Reduce Air Pollution
Here is how to reduce indoor air pollution with house plants, irrespective of the choice of plants you use. The important factors are having enough plants for the volume of air to be purified, and the level of air contamination. Naturally, the greater the concentration of volatile organic substances in your air, then the more plants you will need.
Select your preferred plants and then use one 10 -12 inch plant for each 100 square feet of floor space at an average room height of 8-10 ft. Make sure you are using the correct plant – select by botanical name rather than common name, since the latter can vary. Your plants should receive enough sun and the watering periods scheduled according to the needs of the species used. Use rainwater to water your plants wherever possible.
Make sure the leaves are regularly dusted and washed when required, to keep their pores unblocked and open for maximum absorption rates. Your houseplants will thrive best in a rich organic loan or compost – try to avoid inorganic fertilizers.
If you keep all of the above suggestions in mind and choose the right indoor house plants, you should be able to reduce indoor air pollution and maintain a healthier home. Indoor plants do help to clean the air, and you can use this to maintain a healthier atmosphere in your home.
References:
1. Akira Tani and C. Nicholas Hewitt “Uptake of Aldehydes and Ketones at Typical Indoor Concentrations by Houseplants” Environmental Science & Technology, American Chemical Society, October 6, 2009
2. S Down. Spectroscopynow.com (2009) “Houseplants as air fresheners” Spectroscopynow.com.
3. Yang, Dong Sik, Pennisi, Svoboda V., Son, Ki-Cheol, Kays, Stanley J. “Screening Indoor Plants for Volatile Organic Pollutant Removal Efficiency” HortScience, 44: 1377-1381 (2009).
Bibliography:
Wolverton BC, Wolverton JD. (1996). Interior plants: their influence on airborne microbes inside energy-efficient buildings. Journal of the Mississippi Academy of Sciences.
Wolverton BC, Johnson A, Bounds K. (1989). Interior Landscape Plants for Indoor Pollution Abatement. NASA.
Wood, R.A. 2003. Improving the indoor environment for health, well-being and productivity. In: Greening cities: A new urban ecology. April 30th, 2003 – Australian Technology Park, Sydney, Australia.
