Inside one New Delhi office building, there are four times more plants than people. The greenery makes up part of a natural filtration system: When the building sucks in the smoggy outdoor air in the world’s most polluted city, the plants help make it safe to breathe.
“People have a wrong notion in their mind that air pollution is something that takes place only outside,” says Kamal Meattle, CEO of Parharpur Business Centre (PBC) and designer of the plant-based air purification system. “Indoor air is typically 10 times more polluted than outside.”
On the roof of Meattle’s building, scrubbers remove chemicals like nitrogen oxide from outdoor air and then send it into a greenhouse filled with plants like Areca palm. The plants clean the air more, using a hydroponic system that the company says makes the plants more efficient at pollutant filters. The greenhouse then sends fresh oxygen into the building, which has hundreds more plants on each floor.
Meattle first created the plant-based filter when his own health deteriorated. “About 20 years ago, I became allergic to Delhi’s polluted air,” he says. “My lungs’ capacity went down. Soon, I realized the negative impacts of air pollution and how it can affect one’s health. I was advised by my doctors to leave Delhi. It was left to me to decide whether I should run away from the problem or work towards finding a solution that can easily be mainstreamed and help one and all.”
Though some scientists argue that plants alone can’t effectively clean indoor air, the system seems to work. PBC employees are less likely to get sick or suffer problems like headaches or eye irritation, say studies from the Indian government. They’re even 20% more productive.
Unlike a typical building ventilation system, the greenhouse filter also uses little energy. “Plants are very critical to our system as it not only impacts the indoor environment, but also helps in reducing the energy consumption level,” Meattle explains. “A lesser volume of ambient air is required to be pumped into the building, thereby saving cooling or heating energy.”
The company eventually decided to start building similar systems for others. PBC now replicates the system for other offices, hospitals, schools, shopping malls, and homes in India, and plans to start selling internationally as well.
They also hope to make people think about the fact that indoor air–even in less polluted cities–tends to be unhealthy. “On average, we drink two to four liters of water per day but breathe over 11,000 liters of air per day,” Meattle says. “We are very concerned about the water we drink–bottled mineral water it is, for a lot of us! For the quality of air we breathe, do we care enough?”