Mold, like most fungi, is ubiquitous in both indoor and outdoor environments. Mold can grow on almost any surface as long as there is sufficient moisture in the environment and organic material to feed on. Because most mold spores are microscopic, they are not visible to the naked eye making it impossible to completely eradicate them. Thus, controlling indoor moisture is key to preventing indoor mold growth. Potential health effects of mold can vary from severe allergic reactions to no effects at all. Individuals vary highly in their sensitivity to mold. However, even if a person doesn't experience severe reactions to mold despite living in a home where it’s found, symptoms can develop at any point and tend to worsen over time.
Mold can concentrate in areas inside the home that experience the most moisture, such as bathrooms. Another common place to find mold is under carpets, which can be much more inconspicuous. Cold surfaces, such as outside walls, can be an area where condensate forms and gravity pulls the droplets to the floor and creating an environment for mold growth. Anywhere in the home where condensate forms can be a potential breeding ground for mold. While mold can be detected visually most of the time, mold can grow in areas hidden from view. Hidden mold growth can make it difficult to detect and remediate. Often, a room will smell moldy or "stuffy," providing clues that there is mold growth. It is important to educate the community to look for mold behind furniture, under the carpet, the back of walls, etc.
levels vary widely from region to region. As a rule of thumb, homes should have an RH level of 30-60%. Levels higher than 60% promote mold growth in most environments. During home assessments conducted over the week of September 12th, the four homes that were assessed presented a RH level from 50-60%, on the higher end of normal. The days when the assessments were conducted were particularly humid days, which is the norm in Humboldt County.
Environmental Protection Agency
California Childcare Health Program
Integrated Pest Management for Mold .pdf