February 2009

from TED Website



With its air-filtering plants and sustainable architecture,

Kamal Meattle's office park in New Delhi

is a model of green business.

Meattle himself is a longtime activist

for cleaning up India's air.


Researcher Kamal Meattle shows how an arrangement of three common houseplants, used in specific spots in a home or office building, can result in measurably cleaner indoor air.







Some 17 years ago, I became allergic to Delhi's air.


My doctors told me that my lung capacity had gone down to 70 percent, and it was killing me. With the help of IIT, TERI, and learning from NASA, we discovered that there are three basic green plants, common green plants, with which we can grow all the fresh air we need indoors to keep us healthy.


We've also found that you can reduce the fresh air requirements into the building, while maintaining industry indoor air-quality standards.

The three plants are,

The botanical names are in front of you.

  • Areca palm is a plant which removes CO2 and converts it into oxygen. We need four shoulder-high plants per person, and in terms of plant care, we need to wipe the leaves every day in Delhi, and perhaps once a week in cleaner-air cities. We had to grow them in vermi manure, which is sterile, or hydroponics, and take them outdoors every three to four months.


  • The second plant is Mother-in-law's Tongue, which is again a very common plant, and we call it a bedroom plant, because it converts CO2 into oxygen at night. And we need six to eight waist-high plants per person.


  • The third plant is money plant, and this is again a very common plant; preferably grows in hydroponics. And this particular plant removes formaldehydes and other volatile chemicals.

With these three plants, you can grow all the fresh air you need.


In fact, you could be in a bottle with a cap on top, and you would not die at all, and you would not need any fresh air. We have tried these plants at our own building in Delhi, which is a 50,000-square-feet, 20-year-old building. And it has close to 1,200 such plants for 300 occupants.


Our studies have found that there is a 42 percent probability of one's blood oxygen going up by one percent if one stays indoors in this building for 10 hours. The government of India has discovered or published a study to show that this is the healthiest building in New Delhi.


And the study showed that, compared to other buildings, there is a reduced incidence of eye irritation by 52 percent, respiratory systems by 34 percent, headaches by 24 percent, lung impairment by 12 percent and asthma by nine percent.


And this study has been published on September 8, 2008, and it's available on the government of India website.

Our experience points to an amazing increase in human productivity by over 20 percent by using these plants. And also a reduction in energy requirements in buildings by an outstanding 15 percent, because you need less fresh air. We are now replicating this in a 1.75-million-square-feet building, which will have 60,000 indoor plants.

Why is this important?


It is also important for the environment, because the world's energy requirements are expected to grow by 30 percent in the next decade. 40 percent of the world's energy is taken up by buildings currently, and 60 percent of the world's population will be living in buildings in cities with a population of over one million in the next 15 years.


And there is a growing preference for living and working in air-conditioned places.

"Be the change you want to see in the world," said Mahatma Gandhi.











Growing Fresh Air

...With Common House Plants


from Heartspring Website




Air filtering plants




Bill Wolverton MD, author of How To Grow Fresh Air, explains how plants and their companion microorganisms are used to create a closed ecological life support system for long duration space habitation.


His research included wastewater recycling as well as the purification and revitalization of indoor air.


Indoor air pollution can be higher inside the home than outside, especially in during winter months. For larger buildings this approach works to reduce energy requirements for air circulation and provides a cost savings, helping to comply with indoor industrial air quality standards.


Here are the three plants doctor Wolverton identified best suited to improving air quality and the number of plants required to provide a healthier indoor breathing environment:




Day Time Oxygen Production

  • Areca Palm, Golden Palm, Chrysalidocarpus lutescens

  • 4 plants, shoulder-high, per person


Areca Palm



The Areca Palm breathes in carbon dioxide and breathes out oxygen during the day.


In excessively dirty air conditions, such as in city of Mumbai India, plant leaves are wiped clean once daily with a moist soft cloth. In cities with cleaner air, this is done once weekly. The Areca Palm prefers to have its soil slightly dry between watering and thrives in full sun.


Moving the Areca Palm outdoors every three to four months will help rejuvenate healthy plant growth.




Night Time Oxygen for Sleeping

  • Snake Plant, Sansevieria trifasciata

  • 6 to 8 plants, waist-high, per person


Birds Nest, Snake Plant



The snake plant releases oxygen during the night, helping to condition indoor air while humans and pets sleep. The snake plant prefers intermittent dry conditions and full sun, but it can survive in low light conditions.




Absorbing Toxic Aerosols In The Work Area

  • Pothos, Money Plant, Epipremnum aureum

  • 3 plants per person, 18 inches high


Golden Pothos



The Pothos plant absorbs toxic vapors, working to remove volatile organic chemicals (VOC's) including paint fumes, solvents, and petroleum fuels. Many toxic vapors are in homes come from fumes coming from sources such as flame retardants in furniture and common household cleaners.


According to the Environmental Protection Agency, about 700 "secret chemicals" are added to products every year in the United States. See Washington Post article about secret chemicals


The Pothos plant is a moisture loving plant and handles low light conditions well.


With these three plants, it's possible to grow enough the fresh air to stay alive inside a closed environment for a long period of time.





Office Building Air Quality Research


These three plants where tested for 15 years at Paharpur Business Centre and Software Technology Incubator Park in New Delhi, India.


The 50,000 square foot building is 20 years old and contains over 1,200 plants for 300 working occupants.


The Paharpur office building is rated the healthiest building in Delhi by the Government of India. This study was published in September, 2008 by the Government of India, Central Pollution Control Board and the Chittaranjan National Cancer Institute, Kolkata, India.


The study found that there is a 42% probability of increasing blood oxygen by 1% if one is inside the building for 10 hours.


Compared to other non-planted buildings in Delhi, the Paharpur Office Building showed reductions in:

  • Eye Irritation - 52%

  • Respiratory Conditions - 34%

  • Headaches - 24%

  • Lung Impairment - 12%

  • Asthma - 9%

Because of the fresh air produced by the buildings’ plants, there was a 15% reduction in energy costs. This is significant reduction in cost considering that 40% of the world’s energy is used to maintain building environments.


The most surprising discovery in this study was a measured 20% increase in human productivity and marked decrease of employee sick days.