Question

How do you know if undesirable molds are present in an area?

Answer 1

The air quality is the biggest way to determine whether or not there are mold present. If the air quality is musty, or smells odd then some type of molds are probably present

Answer 2

When somewhere covered in mold you may not even see it, but a good way to know its there is the smell, or the quality of the air. If the air feels musky and gross there could be some mold somewhere.