Mould is a natural accruing microscopic fungi that grows indoors and outdoors. Mould produces spores and mycelia very rapidly if the right conditions exist.
Some mould can produce spores that have microtoxins that are very harmful if inhaled.
Mould comes in many colours. Typically common is what appears as black mould growing indoors. Mould grows on many surfaces such as porous items like wood, paint, plaster, drywall, dust, concrete and carpet just for example. Some moulds produce a musty like smell such as a wet forest or damp towel. There is visible and hidden moulds; most occur due to a significant amount of water.
Long term inhalation of indoor mould spores eventually will lower your immune system. You may need to seek medical attention if these symptoms persist.
Although each individual can tolerate mould differently, the following groups should not be exposed to mould: