Indoor Air sciences CSMI Practice Exam

What can excessive humidity levels in a building lead to?

1. Increased dust levels

2. Mold growth

3. Allergic reactions

4. Increased energy costs

The correct answer is: Mold growth

Excessive humidity levels in a building can lead to mold growth because mold thrives in damp environments where moisture levels are high. When humidity rises above a certain threshold, typically around 60%, it creates favorable conditions for mold spores to settle and proliferate on various surfaces, including walls, ceilings, and even within materials like wood and drywall. This not only compromises indoor air quality but also poses health risks to occupants, as mold can trigger allergic responses and respiratory issues. While the other options may have some indirect connections to high humidity, they do not directly stem from humidity levels as prominently as mold growth. For instance, while increased dust levels may occur, they are more influenced by poor cleaning practices or ventilation rather than humidity itself. Allergic reactions can be triggered by various allergens, but without the presence of mold or other specific irritants, humidity alone does not cause them. Increased energy costs are more closely related to other factors like insulation and HVAC efficiency rather than humidity levels per se. Thus, mold growth stands out as the direct consequence of excessive humidity.