A Primer on Sick Building Syndrome

“Sick Building Syndrome” otherwise known as poor indoor air quality ("IAQ") renders building occupants sick and/or makes pre-existing symptoms far worse, giving rise to an entire legal industry.  Poor IAQ may result from multiple sources, including insects, rodents, asbestos, dust, chemicals pesticides, pet fur, lack of ventilation, and  carbon based fuels.  But the most common source of poor IAQ is microbial growth - resulting from blooms of mold, mildew and other fungi that release spores into into the air.  [See, “Revisiting the 1976 Legionnaires Disease Outbreak!”, posted 12/4/24].  All forms of such fungi reproduce by releasing microscopic spores (i.e. seeds) into the air that can travel freely around a building and into the lungs of any occupants.  Spores may remain alive and able to grow for years, and the allergens within spores can remain allergenic even after the spores are dead. 

Fungi require very simple needs to grow and reproduce - warmth, moisture, food and oxygen.  Ideal temperatures typically range between 40 and 100 degrees Fahrenheit, well within the range of normal building temperatures. Moisture can result from multiple causes, including plumbing leaks, roof leaks, high humidity, storms, accidents, or even HVAC equipment many of which are common in older buildings.  Food needed to support molds, consist of dead organic material including wood, cardboard, paper facing on gypsum board (drywall) and other materials made from wood.  Oxygen is a common element required for the survival of both humans and mold, but unlike normal living conditions, molds prefer low light as this contributes to higher moisture content due to less evaporation.

There are four (4) common types of molds that grow in buildings under the proper conditions, the most harmful of which Stachybotrys chartarum or Stach.  Stach is a greenish-black mold, thriving in high-moisture areas on building materials like fiberboard, gypsum board, or paper and typically appears after water damage or flooding.   Stach requires a constant source of moisture in order to grow and reproduce.  Prolonged exposure to Stach can lead to severe symptoms like nausea, lung issues, and even bleeding, with greater risks for those with allergies or weakened immune systems.  

The other three types of molds are less harmful, but still pose potential serious health problems.  Penicillium molds are the most common indoor types and appears in bluish-green, fluffy blooms.  Penicillium grows in most areas such as between floor tiles and basements after exposure to water or flooding.   Penicillium grows in cool, damp environments and can trigger allergies, asthma, and heart inflammation, especially in immunocompromised individuals.   Aspergillus molds are present everywhere, both indoors and outdoors, and grow in humid areas, such as HVAC systems.  There are approximately 180 species of Aspergillus, 40 of which can cause respiratory infections in humans.  Most people inhale aspergillus spores every day and never get sick.  While generally harmless, it can pose health risks to those with compromised immune systems or lung conditions.  Finally, Cladosporium molds grow in damp areas like basements and bathrooms, and appear in brown or green clusters. While it has minimal impact on health, long-term exposure can worsen allergies and asthma. 

Most all molds and fungi, can be easily eliminated through exposure and   treatment with common over the counter bleach otherwise known as a mixture of water and sodium hypochlorite.   However, the molds must first be located and identified before treatment can occur, which can be difficult if located inside walls, uninhabited spaces, or other inaccessible areas.  In such cases, IAQ testing and monitoring may be required to identify the risk before building occupants are exposed to serious health risks.  As with most health risks, knowledge of cause and effect is critical.