Indoor Air sciences CSMI Practice Exam

Which microbe cannot colonize building materials?

1. Bacteria

2. Algae

3. Viruses

4. Mold

The correct answer is: Viruses

Viruses are non-cellular entities that require a host cell to replicate and cannot exist independently outside of a living host. Unlike bacteria, algae, and mold, which are capable of colonizing surfaces, including various building materials, viruses do not have the necessary means to attach to or grow on these substrates. They rely on infecting living cells to propagate, which limits their ability to establish colonies in indoor environments. In contrast, bacteria, algae, and mold all have mechanisms that allow them to thrive on surfaces found in buildings, leading to the potential for biofilm formation, growth, and, in some cases, harmful effects on indoor air quality. Hence, the distinct nature of viruses as obligate parasites sets them apart as the correct answer for a microbe that cannot colonize building materials.