What does thermal stratification refer to in indoor environments?

Thermal stratification refers to the phenomenon where layers of air within a space have different temperatures, creating a temperature gradient. This occurs due to factors such as heating systems, occupancy, and building design. In indoor environments, warmer air tends to rise while cooler air settles, leading to distinct layers—this is especially noticeable in spaces with high ceilings or insufficient mixing of air. Understanding thermal stratification is important because it can impact energy efficiency, comfort levels, and even indoor air quality.

The other options do not accurately describe thermal stratification. The mixing of different indoor pollutants involves air quality dynamics rather than temperature variations. A uniform temperature distribution would indicate no thermal stratification at all. Lastly, while outdoor temperature can affect indoor climate, it does not directly define thermal stratification, which is specifically related to the layering of temperatures within the indoor space itself.