How sampling works
What Mold Testing in Florida, NY Really Measures
At its core, mold testing is about capturing spores and letting a lab count them. For air, the sampling pro attaches a sealed spore-trap cassette to a pump calibrated with a rotameter, then runs it at a set flow rate, often 15 liters per minute for 5 minutes, which pulls 75 liters of air across a sticky slide. The lab counts and identifies what landed on that strip under a microscope, then converts the count to spores per cubic meter of air.
A single indoor count tells you very little without a comparison. Outdoor air always carries spores, which is why a control sample gets taken outside during the same visit. If indoor levels run well above outdoor levels, or the indoor sample is dominated by types like Stachybotrys or Chaetomium that rarely show up outside in any quantity, that points to an indoor source. There are no federal numeric limits for indoor spores, which is exactly why the outdoor comparison carries so much weight.
Surface sampling answers a different question: what is this stain? Tape-lifts grab spores and hyphae from smooth surfaces, swabs handle textured spots, and bulk samples are small cut pieces of the material itself. A wall-cavity air sample, drawn through a tiny hole, can show whether a closed cavity is loaded with spores. Most Florida callers want testing for paperwork: a real estate disclosure, a tenant complaint, or proof a cleanup worked.