The idea that houseplants purify indoor air traces back to a 1989 NASA study conducted for space station research — and it has been widely misread ever since. The study was carried out in sealed chambers with artificially high pollutant concentrations, conditions that have almost nothing in common with a real home. The critical variable most plant studies ignore is the air exchange rate — how quickly outdoor air naturally replaces indoor air through walls and ventilation. A 2019 study modeled plant performance against real-world air exchange rates and found you'd need between 10 and 1,000 plants per square meter to match what a building's passive ventilation already does on its own. Houseplants can remove some pollutants — but they are not an effective air-cleaning solution. The original science wasn't wrong. It was just never meant to apply to your living room. #IndoorAir# #Houseplants# #NASA# #Science# #HealthMyths#