The Clay-based Air-treating Living-wall Module (CALM) combines a 3-D clay-printed Triply Periodic Minimal Surface (TPMS) shell with a hydrogel/zeolite/perlite/vermiculite substrate to create a winddriven, flow-through brick that cleans incoming outdoor air. Full-scale tests in a 35°C closed-loop wind tunnel show that, even without vegetation, the substrate dampened the formaldehyde spike by 17.8%, accelerated the 1-hour decay rate by 17.6%, and cut the 90-min residual to around 202.3 µg/m³, which is below the 500 µg/m³ TVOC reference limit set by LEED and WELL. A preliminary test identified the same substrate (25% hydrogel, 15% zeolite, 30% perlite, 30% vermiculite) as the best trade-off between air permeability, water retention, and Plantago major viability. These results establish a non-biological baseline and confirm CALM’s promise as a low-energy façade element; planned work will integrate vegetation, assess long-term performance in diverse climates, and include a full-scale installation.
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