Mold is a group of microscopic organisms that are part of the Fungi Kingdom. They generally reproduce by means of spores and are ubiquitous (found everywhere). Often, the terms mold and fungi are used interchangeably.
What Causes Mold to Grow? A damp indoor environment promotes the proliferation of mold. There are three key elements that constitute favorable conditions for the colonization of mold and fungus (microbial organisms): nutrients, moisture, and temperature. Molds are most commonly found outdoors on decaying plants however, when mold spores are introduced into an indoor environment, they can grow rapidly under the proper conditions as long as the three key elements are present.
Indoor nutrient sources for mold growth can be any organic material provided by a flood or sewer backup, cellulose based materials present in the building such as drywall, carpet backing, linoleum backing, drop ceiling tiles, or the buildup of plant and/or animal debris on inorganic surfaces. Skin cell fragments are a significant food and colonizing source in the office buildings and private homes where high occupancy exists or adequate housekeeping is not performed.
Moisture sources in buildings occur most commonly as water leaks, sewer leaks, moisture intrusion through walls and foundation or as condensation in HVAC systems (EPA, Biological Pollutants in Your Home, 1997). Conditions under which indoor mold growth can occur include:
- Historical flooding without proper cleanup
- Moisture intrusion occurring through subflooring or walls
- Rainfall entering through leaky roofs
- Plumbing or water line leaks
- Toilet overflow or sewer backups
- Moisture condensation within HVAC systems and,
- Persistent elevated relative humidity above 62% and inadequate housekeeping.
Molds colonize most readily when air disturbance is minimal. For this reason, mold colonization occurs most frequently in closed or concealed spaces such as closets, storerooms, basements, and refrigeration units, or on the back or underside surface of furniture. Fungi can cause the discoloration of materials, odor problems, deteriorate building materials, and can lead to allergic reactions in susceptible individuals as well as other health problems.
Due to the abundant diversity of microorganisms found in the environment and the influence of normal humidity and temperature conditions, the concentrations of molds vary significantly from region to region. Generally speaking, the total indoor airborne mold spores should be quantitatively lower and similar (genus or species) to that of outdoor air.
What to do if Mold Growth is Observed? The presence of mold growth, water damage, or musty odors should be addressed quickly-within 24 to 48 hours if, at all, possible. In all instances, any sources of water intrusion must be identified and corrected immediately. In addition, the extent of water damage and/or mold contamination should be identified and corrected to prevent exposure problems or health issues. Be aware of who is contracted – only experienced and credentialed remediation companies should conduct any mold remediation utilizing proper engineering controls.
It is neither possible nor warranted to eliminate the presence of all indoor fungal spores and fragments; however, any mold growth indoors can and should be removed and/or prevented wherever possible.