A normal mold air sample doesn’t always mean your home is mold-free. Air samples only capture what passes through the testing device during a short window of time. If mold is hidden behind walls, under flooring, behind cabinets, or inside HVAC-related areas, spores may not be moving through the sampled air when the test is taken. That’s why homeowners can receive “normal” results even when a musty smell, moisture history, or health concerns continue. This article explains why mold air samples can come back normal and when a mold dog inspection may help locate the hidden source.