ERMI tests are legit if you're a scientist studying IAQ, which is what ERMI was designed for. Since almost all buildings have mold spores, collecting dust from a building will unsurprisingly result in a positive presence of spores. So essentially, no building will ever 'pass' an ERMI test.

Air sampling is the most accurate method for determining exposure. While a tape lift may accurately determine if mold growth is present on a particular surface, it will not tell you whether that mold growth has actually affected the indoor air quality. Only an air sample can accomplish this.

borescope: This is a camera that can visualize suspected mold growth and other problems inside plumbing pipes and structural elements through an opening in the component. rotameter: This device measures the air flow rate, which can be helpful to determine if the home has conducive conditions for mold growth.