What does the amount of emitted electromagnetic radiation (EMR) from an object depend on?

The amount of emitted electromagnetic radiation (EMR) from an object is fundamentally influenced by its temperature. According to Planck's law of blackbody radiation, as the temperature of an object increases, it emits more electromagnetic radiation across a wider range of wavelengths. This relationship means that hotter objects emit more energy and shift the peak of their emission spectrum to shorter wavelengths, which can be observed in phenomena such as the visible glow from heated materials.

In contrast, while factors such as humidity, pressure, and wind speed can affect the behavior of EMR in the atmosphere — including its absorption, scattering, and transmission — they do not directly alter the intrinsic amount of electromagnetic radiation emitted by an object based on its properties. Therefore, temperature is the key factor in determining the level of emitted EMR.