Plants Can Help Clean Indoor Air
NASA Research on Reducing Indoor Pollution
NASA (US National Aeronautics and Space Administration) proved as long ago as 1989 that having plants in an enclosed space can improve breathable air quality by up to 90%. This has been confirmed in later studies.
The aim of NASA’s Clean Air Study was to find sustainable ways to remove pollutants from recycled air. Astronauts spend many weeks in enclosed spaces. Maintaining good air quality on the journey and in the space station is essential to their survival. Plants absorb carbon dioxide from air and replace it with oxygen, so it was a natural step to test their ability to absorb other pollutants. NASA used the principle of phytoremediation as the basis of their experiment.
What is Phytoremediation?
Phytoremediation means using plants to reduce indoor and outdoor air pollution. “Phyto” (from Ancient Greek) means plant and “remediation” (from Latin) is the process of stopping or reversing environmental damage.
Trees and green spaces provide an environmental “lung” for urban areas. Green belts of farmland and woodland around big cities are an example of remediation of outdoor air pollution. The vast Amazon rain forests are an example of natural remediation that helps maintain good air quality worldwide. NASA’s research has shown that indoor plants are also effective at improving interior air quality.
Plants Are Natural Air Filters
Some Health Damaging Pollutants Found Indoors
Combustion (room heating), cleaning, cooking, smoking.
Combustion (room heating) and smoking.
Polycyclic aromatic hydrocarbons
Combustion (room heating), cooking and smoking.
Arsenic and fluorine
Volatile and semi-volatile organic compounds
Fuel/tobacco combustion, consumer products, furnishings, construction materials, cooking
How to Reduce Indoor Air Pollution
1. Reduce or remove the source of the pollution. For example, have your boiler serviced regularly so that it burns without producing dangerous carbon monoxide. You could also forbid smokers from lighting up indoors as second-hand smoke contains carcinogens.
2. Improve room ventilation. Increasing the number of air changes per hour will remove many pollutants.
3. Use air cleaners to filter and remove pollutants. There are many mechanical air cleaners on the market, but they can be expensive to buy and maintain. The NASA research study has shown that house-plants provide a practical, low cost, and easy to maintain alternative.
The lead scientist investigator on NASA’s Clean Air Study was Dr. B. C. Wolverton. In "" he gives a comprehensive list of the 50 best house plants for improving your indoor air quality. He discusses each plant’s ability to filter out and remove common pollutants such as ammonia, formaldehyde, and benzene. He also gives guidance on which ones are easy to care for and which rooms they would suit best. The NASA study concluded that you need at least one indoor plant for every 100 square feet of floor space for an effective result. The video below gives some examples of beneficial plants which are low maintenance. How to Grow Fresh Air: 50 House Plants that Purify Your Home or Office
Plants For Clean Air
Indoor Pollutant Sources
The US Consumer Product Safety Commission says that indoor pollution sources include the following.
".. building materials, furnishings, and household products like air fresheners, release pollutants more or less continuously. Other sources ... include smoking, the use of unvented or malfunctioning stoves, furnaces, or space heaters, the use of solvents in cleaning and hobby activities, the use of paint strippers in redecorating activities, and the use of cleaning products and pesticides. High pollutant concentrations can remain in the air for long periods after some of these activities."
How toxic is the air in your home?
Detox Your Home with NASA’s Advice
The top ten best air filtering house plants according to NASA are as follows.
1. English Ivy (Hedera Helix). This is low maintenance and grows in virtually any indoor conditions. It is recommended for removing carcinogens from second-hand tobacco smoke.
2. Golden Pothos (Epipremnum Aureum). This was NASA’s top recommendation for the removal of formaldehyde from interior air. It is also good at removing carbon monoxide.
3. Boston Fern (Nephrolepis Exalta Bostoniensis). This large ornamental fern has great visual impact and is easy to care for. It is acts as an air humidifier as well as helping to eliminate formaldehyde.
4. Dracaena (Dracaena Deremensis). This is a very large plant which may not be suitable for many homes, but it can be useful for offices to eliminate trichloroethylene that comes from solvents and varnishes.
5. Bamboo Palm (Chamaedorea Elegans). NASA found this small decorative palm to be a good air filter for benzene and trichloroethylene as well as a great air humidifier. It is easy to grow and is resistant to insect attack.
6. Dragon Tree (Dracaena Marginata). This one is low maintenance and is recommended for offices and homes which need to remove xylene from the air. Xylene is released from car exhaust, paints, and cigarettes.
7. Peace Lily (Spathiphyllum). This is an attractive plant and good at removing indoor air pollutants. However, if eaten, its leaves can be poisonous. It therefore should not be placed in areas that are used by children or pets.
8. Lady Palm (Rhapis Excelsa). This palm requires frequent watering in hot weather, so it is not as easy to care for as some of the other suggestions. It is an attractive plant and effectively reduces multiple indoor pollutants.
9. Spider Plant (Chlorophytum Comosum). This grows well in bathrooms and kitchens where the air is moist. It requires very little attention and removes carbon monoxide from the air.
10. Snake Plant (Sansevieria Trifasciata). The snake plant is a good all-rounder and is low maintenance. It absorbs formaldehyde and other chemical air pollutants.
NASA Clean Air Study Results in Big Improvement to Air Quality
For more information on the various indoor pollutants found in your home “” by the US Environmental Protection Agency is a useful read. It explains what the pollutants are and how they affect your health. It outlines practical steps you can take to improve the quality of the air you breathe at home and in your workplace. The Inside Story: A Guide to Indoor Air Quality
The research referred to in the article is “Interior Landscape Plants for Indoor Air Pollution Abatement” B.C. Wolverton, A Johnson, and K Bounds. It was published as a NASA report on September 15th 1989.