Indoor Air sciences CSMI Practice Exam

What type of surface is commonly considered a breeding ground for mold?

1. Drywall

2. Metal

3. Glass

4. Plastic

The correct answer is: Drywall

The choice of drywall as a breeding ground for mold is well-founded due to its composition and moisture retention properties. Drywall is made of gypsum, which is a mineral that provides an ideal porous substrate for mold spores to adhere to and grow, especially in environments with elevated humidity or water intrusion. Moreover, drywall often has paper backing, which is also conducive to mold growth. When moisture is present—such as from leaks, high humidity, or flooding—these materials can create a perfect environment for mold development. In contrast, surfaces like metal, glass, and plastic are much less susceptible to mold because they are non-porous and do not retain moisture as effectively. Metal and glass tend to have smooth surfaces that do not allow for mold spores to settle and germinate easily, while plastic can be resistant to moisture absorption depending on its type. Thus, drywall stands out clearly as the surface most commonly associated with mold proliferation.