Greenairy builds smart plant towers to clean toxic gases from office air

The idea began when Thombre and Saraf were engineering students working in their university makerspace. Thombre said via email that they were “unknowingly exposed to toxic fumes from laser cutters, 3D printers, and soldering irons,” but did not realize it until her best friend fainted and had to go to the hospital. After that, she said, “We began investigating indoor air pollution and realized it was an invisible but dangerous health risk — especially in schools, offices, hotels, salons, and any commercial buildings where air-conditioning prevents windows from being opened.”

The problem persists even in buildings with air purifiers, as their makerspace had, according to Saraf. Purifiers are good at cleaning particulate matter such as dust and pollen, but less effective at removing toxic gases such as carbon dioxide, formaldehyde and benzine, many of which are volatile organic compounds, or VOCs — chemicals that evaporate easily into the air. Thombre said VOCs are linked to chronic disease and “sick building syndrome,” in which occupants experience health effects and discomfort after spending time in a building without a specific cause or illness being identified. She also pointed to Harvard research showing that improving indoor air quality improved cognitive function and productivity.

Greenairy’s approach is to build plant towers that draw in air, break down toxic gases and release purified air. “A plant in a pot cleans air slowly. But, when we change the conditions around the plant, it cleans air much faster and better than these conventional methods,” Saraf said. She also said some air purifier filters can remove “a narrow range of VOCs,” but need frequent replacement to remain effective. Plants, by contrast, are “a natural solution, no harmful byproducts are formed, and no filter replacement is required.”

Greenairy has conducted short-term pilots around Singapore. Saraf said the startup’s own testing, using RESET-certified air monitors, compared three offices: one with Greenairy plant towers, one with a medical-grade ionizer, and one with a HEPA air purifier that traps very small particles. “Our tower had the lowest VOC levels and removed VOCs the fastest,” she said. “The office staff also grew fond of the natural ‘fresh’ aroma of the tower and the natural vibe it brought.” Thombre added that they saw an “immediate” improvement during regular office hours, with a 50% reduction in both the daily VOC average and peak levels. She said results improved further “as the plants and microbes mature and the gases are prevented from accumulating.”

The company said its results have been validated by German testing and certification firm TÜV SÜD and will be published soon, with results available upon request in the meantime. The founders plan to begin large-scale manufacturing after the results are certified. Saraf is based in Berkeley, California, and Thombre in Singapore. Saraf said the arrangement “works well at this stage,” allowing one founder to focus on testing in Singapore while the other fundraises in the Bay Area. “If things go to plan, both of us will be in Singapore by the first half of 2027,” she said. “That’s when we expect to launch our first mass-produced towers and install them for our first customers” in Singapore.