Which factor does NOT affect the effectiveness of ventilation systems?

The effectiveness of ventilation systems is influenced by various physical and environmental factors that directly impact air circulation and quality within a space. The color scheme of the walls does not play a role in the mechanics of how air moves through a building nor does it have any impact on temperature differentials, airflow rates, or the overall building layout.

Effective ventilation relies on characteristics such as airflow rate, which measures how much air can be moved in a given time, temperature differences that can create natural convection, and the building layout that determines how air flows through spaces. These factors impact the efficiency with which fresh air is brought in and stale air is removed. Therefore, while other choices are crucial for optimizing ventilation, the aesthetic choice of a color scheme does not affect systematic air movement in any meaningful way.