
Why I’ve Never Seen Wallemia sebi on a Swab — and Why That Matters: How Dust-Associated Fungi, Sampling Limitations, and Respiratory Health Intersect in Indoor-Air-Quality Investigations
How many times have you been asked to check an HVAC system for mold? A thousand? You pull a couple of air samples. You swab the coils—if you can reach them. The lab report comes back showing a familiar result: Cladosporium. Case closed. Or is it? After years in the field, thousands of inspections, and countless viable and non-viable samples, there is one organism I’ve never seen directly identified on a surface swab: Wallemia sebi. That isn’t an oversight. It’s a sampling limitation and it explains why some buildings test “normal,” yet occupants continue








