If you have smell of mold in a basement and high humidity, this is definite warning signs. If your home or business feels humid there is enough moisture in the air to easily help mold spores colonize. You can begin looking behind sheetrock, look in the laundry or utility rooms and in the closet under the stairs. You might want to try a dehumidifier this may be helpful along with air circulation.
If you believe you are experiencing any of these warning signs, call in a professional for an inspection to make sure you have no immediate health risk. Mold "Remediation" is much more than just cleaning up the mold.