by Michael E. Goldberg, CIH, CSP
How does mold get into a home or building? Let us start by recognizing that mold and fungal spores occur naturally outdoors. Outdoors, molds play a part in nature by breaking down dead organic matter such as fallen leaves, dead trees, and other debris. When indoors, mold needs moisture to grow; it becomes a problem only where there is water damage, elevated and prolonged humidity, or dampness. Common sources of excessive indoor moisture that have the potential to lead to mold related problems include flooding from surface/ground water, roof leaks, storm driven rain through window frames or exterior walls, leaking pipes within the building or home infrastructure, and condensation on leaking surfaces or HVAC duct work.
What are the health impacts of mold? The Centers for Disease Control and Prevention (CDC) discussed that exposure to damp and moldy environments may cause a variety of health effects to individuals, or none at all. Some people are sensitive to molds and may experience symptoms related to their exposure. Mold in the indoor environment may lead to allergy “like” symptoms, such as stuffy nose, wheezing, and red or itchy eyes or skin. People in “sensitive groups,” such as immunocompromised are susceptible to severe reactions when exposed to mold. Severe reactions may include fever and shortness of breath.
When evaluating a home or building for mold growth contamination that is in litigation the services of a Certified Industrial Hygienist (CIH) or a Certified Safety and Health Professional proficient in indoor air quality should be engaged. The expert should be familiar with building envelope design, ventilation, mold/microbial sampling, and be able to analyze and interpret biological sampling results. Prior to an inspection it is beneficial to inform the expert of any history of leaks or occupant complaints. This would include any reports by the occupants of musty or moldy odors.
The home or building should be inspected to check materials and spaces for visible mold growth. In addition, the ventilation and/or HVAC systems may warrant inspection, with particular emphasis on the filters, cooling coils (if present), the fan chamber, and any internal insulation. The expert should examine the exterior areas to identify potential locations of entry of moisture and/or water followed by interior areas of the home or building that may have been impacted from exterior water infiltrations. Moisture readings obtained by using instrumentation should be used to determine what materials have been impacted by moisture, water intrusion, and/or leaks.
If deemed necessary by the expert, sampling for mold may be necessary to evaluate the depth or impact of mold growth from water infiltration or moisture into the indoor environment. The expert must be proficient in sampling, sampling strategy, and technique. They must also be familiar with industrial guidelines for mold sampling. The types of air sampling for mold/fungal growth are air, bulk, and surface samples. The type of sampling performed will be determined by the expert assessing the indoor built environment.
When collecting the samples, it is important that the expert is familiar with aseptic technique, such as wearing gloves during the collection of air, bulk, or surface sampling. In addition, the expert should know to collect a control sample (an area known not to be contaminated) and an outdoor sample for comparison to the indoors. After the collection, samples must be sent to an accredited laboratory for analysis.
Mold growth within certain building elements does not necessarily mean that the indoor environment has been contaminated. For example, when water has infiltrated the building envelope and mold growth is found on sheathing under the exterior stucco finish, this does not necessarily mean the indoor environment has been impacted. The expert can determine whether indoor contamination is present by performing several types of sampling methods (air, bulk, surface), as discussed above, and compare the sampling results of the indoors to the sampling results of the outdoors and/or non-suspect areas.
Currently there are no Federal Standards for airborne or surface concentrations of mold or mold spores. The AIHA and ACGIH recommend comparative sampling (outdoors vs indoors). If the concentration measured is greater indoors than outdoors, and specific water indicator species are prevalent, this may indicate a water-damaged environment and possibly an unhealthy living environment. Assessing mold in the indoor environment can be effectively achieved by understanding the health impacts of mold and its influence on the indoor environment and engaging the right expert to evaluate the incident circumstances.
For more information on assessing mold indoors feel free to contact Mr. Goldberg at 610-240-3480 or firstname.lastname@example.org.