By design, New York City’s new Public Safety Answering Center in the Bronx is a building that will be a tough place to work. Little natural light will enter into the imposing, blast-resistant cube, due to security concerns. Inside the skyscraper monolith, workers will take 911 calls all day and night. The center is also designed to act as a secure base in the event of a natural or manmade emergency. It officially opened in June after years of construction.
In this strange place, a major experiment in green walls is blooming.
The wall, filled with hydroponically grown plants, is aimed at creating a more soothing, pleasant environment, but that's not what's unique. What is different from other green walls is that it also serves an important function in this stifling environment: cleaning the air and enriching the microbiome of the building.
"Conventional HVAC systems are almost like antibiotics. They take the air streams and filter them, and they can take the good out with the bad," says Anna Dyson, director of RPI’s Center for Architecture, Science, and Ecology (CASE).
"We’re essentially looking to transition building systems from antibiotic systems to probiotics systems, if you will. It’s a very different approach."
CASE collaborated with the public safety center’s architects, SOM, and engineers, AECOM, on incorporating the functioning wall into the building. It is far from the first green, or living, wall used indoors—but it is different, says Dyson, because the system, called an Active Modular Phytoremediation Wall, is a functioning part of the building's air quality engineering plan.
Most green walls use soil, and may look pretty, but don’t actually do much for air quality of the building. In fact, the soil—where mold spores can grow—can actually make the air quality worse. The AMPS system, by contrast, is meant to clean the air as it passes through. The project involved careful research to measure air flow rates and how much will be cleaned per minute by a given amount of plants.
"What we’ve been working on is matching up the science and the engineering of how to deliver healthier air," says Jason Vollen, AECOM’s principal for high performance buildings. "Having a building-integrated test bed is absolutely critical to getting new technologies that come out research institutions deployed."
The wall at the public safety center is CASE’s largest deployment of the system. But CASE researchers are also still studying the effects of an AMPS system on the people who occupy a building.
In a classroom at RPI's Troy, New York campus, the researchers have set up a small-scale version to conduct tests on on how plant-based air filtering changes the microbiome of the room—as well as how it affects the people inside. Dyson says tests will include, for example, a study of whether fresher air improves "executive functioning" of subjects, including behaviors like concentration, alertness, and rapid problem solving skills.
Research on plant air remediation originated at NASA, which clearly has an interest in maintaining air quality in closed systems. The researchers' hope is that phytoremediation systems can help supply fresh air in the public safety center building, even if there was an emergency and the building was completely shut off from the surrounding outside environment. That, of course, is a unique problem that isn’t applicable to most other structures. But they will be also be monitoring whether the system saves money or energy in the long-run. The hope is by minimizing the use of expensive-to-maintain mechanical HVAC systems, they can be cost-effective.
"When we are cleaning the air and filtering, we’re accumulating and sequestering toxins. Eventually these filters become toxic themselves," says Dyson. "What we’re talking about with our systems is using biologics to actually reform the toxins. It’s not actually filtering, it’s remediating. That’s the big transition."
Slideshow Credits: 02 / Skidmore, Owings & Merrill LLP (SOM); 06 / Skidmore, Owings & Merrill LLP (SOM);