In May 2024, VerdeTerra completed its first closed-system evaluation of an early indoor air purification prototype, known internally as Prototype7. The goal was straightforward: create a controlled test environment, raise the internal CO₂ concentration, and measure how effectively different systems could reduce CO₂ over time.

This evaluation compared three approaches:

• VerdeTerra’s Prototype7 living air purification system
• A market home air purifier using HEPA and activated charcoal filtration
• Two Spathiphyllum plants, commonly known as Peace Lilies

The test chamber was built as a sealed polycarbonate enclosure with a removable floor, silicone seals, controlled lighting, and a Raspberry Pi-based data acquisition system. Three independent MH-Z19B infrared CO₂ sensors were used to monitor concentrations inside the chamber, along with temperature and humidity sensing. The chamber was first validated for leakage by holding elevated CO₂ levels over a 13-hour test period, resulting in an average leakage rate of approximately 28 PPM per hour.

For each system test, CO₂ levels were raised to approximately 5,000 PPM, then monitored as each system operated inside the closed environment. Prototype7 used six clear photobioreactor tubes containing a mature Spirulina-based culture, with interior air bubbled through the liquid volume to support gas exchange and biological CO₂ uptake.

The results were an important early validation point for VerdeTerra. In one Prototype7 test, CO₂ dropped from an average of 4,700 PPM to 816 PPM over five hours. In a second test, CO₂ dropped from approximately 5,000 PPM to the sensor measurement floor of 400 PPM in 4.5 hours. Across both tests, Prototype7 averaged approximately 900 PPM of CO₂ reduction per hour.

By comparison, the conventional home air purifier averaged approximately 217 PPM of CO₂ reduction per hour, while the two Peace Lily plants averaged approximately 424 PPM per hour during the first five-hour test window. The study found that Prototype7 was up to ten times more effective than the market HEPA/charcoal air purifier and up to five times more effective than the two Peace Lily plants at higher CO₂ concentrations.

This was not a final product test, and it was not intended to represent every real-world indoor environment. It was an early closed-system evaluation designed to answer a foundational question: can a compact, actively managed photobioreactor meaningfully reduce CO₂ in a controlled indoor air volume?

The answer from this first study was yes.

Just as importantly, the test helped shape the next stage of VerdeTerra’s development. It showed the promise of using cyanobacteria-based biofiltration for indoor air quality, while also identifying the engineering work still ahead: automation, long-term stability, maintenance intervals, culture management, scalability, and third-party validation. The original report also acknowledged the need for future independent testing to verify and expand on the early results.

This first closed-system evaluation became one of the technical foundations behind VerdeTerra’s broader mission: to develop air purification systems that do more than trap particles. By combining biological CO₂ reduction with thoughtful engineering and residential product design, VerdeTerra is working toward a new category of living indoor air technology.

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