The difference between toxic mold and allergenic mold

Everyone wants the peace of mind of knowing their home is a healthy place to live. We pay a lot of attention to eating healthy foods and avoiding unhealthy habits, but what about the air we breathe inside our homes? We hear about mold being toxic and a health hazard in the home. Should you be concerned?

Some molds are more hazardous than others, and everyone has a different response to exposure—some people are more allergic, or they have existing respiratory conditions or suppressed immune systems that make the presence of mold in the home more of a health concern.

Many molds found in the home, such as aspergillus or cladosporium (usually found in toilets and air ducts), are non-toxic. However, they are allergenic, and can trigger symptoms such as watery eyes, rashes and a sore/itchy throat.

But other molds, such as stachybotrys atra (a.k.a. black mold), are toxic and can cause reactions such as nausea, chronic coughing, rashes, fatigue and long-term headaches. In addition, for some people, toxic molds can cause infectious diseases, respiratory problems, hypersensitivity reactions, and organ toxicity.

Several factors that affect mold growth:

Nutrient availability—nutrients absorb moisture to maintain a favorable environment for mold growth, and include many surfaces such as soil, dirt, wood, cellulose (paper, ceiling tile, jute carpet backing, cork, pipe wrap), some forms of insulation, fabric, oil, etc.
Moisture content—the amount of moisture in a material influences how an organism can support growth. Moisture sources include condensation in humid rooms, on windows, walls, unheated closets, dampness under carpets and on shower curtains, and periodic wet sections in ductwork of air conditioned ventilation.
Temperature—Temperature is also a factor that affects mold growth; molds typically require temperatures between 5°C and 38ºC to grow.

Important Tip

Moisture is one of the key factors that affect mold growth. There is very little time after a flood to prevent development of an amplification site. Buildings are not sterile and pre-existing mold spores will begin to develop rapidly with the proper nutrient, moisture and temperature combinations. It is important to remove water very quickly (within 24 to 48 hours) after flooding. Surface moisture should be reduced to below 70% relative humidity as soon as possible to reduce the potential for mold growth.