There are over 1 Million different species of mold, but only 10% have been identified in scientic literature.  Not all Fungi are bad or harmful.  There are 6 major factors to consider when dealing with mold.  Temperature, Light, PH, Oxygen, Food Source and MOISTURE.  Mold can begin to grow within  48-72 hours if the circumstances permit it.  Typically all factors are present in an indoor living environment.  In some instances mold can be identified by simply seeing the growth.  There are other indicators, such as mildew or musty odors.  These odors are known as Microbial Volatile Organic Compounds or Microbial VOC's.  They are a gaseous waste product produced during fungal metabolism.  Actively growing fungi produce and release fungal spores for dissemination and survival. This process is referred to as "Sporulation".  Some fungi are "viable", they contain spores that have the ability to germinate given the right circumstances and there are also"Non-viable" spores, which cannot grow into the mold phase.  Mold can attribute to health conditions such as Asthma, Chronic Sinusitis, Imflammation of lung tissue, Histoplasmosis, Cryptoccus and even Meningtis.  Proper evaluations and inspections should be conducted before a scope of work is determined.