Which noise property involves the loudness of the sound?

The property of noise that directly relates to the loudness of sound is intensity. Intensity refers to the amount of energy a sound wave carries per unit area and is commonly measured in decibels (dB). A sound with greater intensity will be perceived as louder to the human ear.

This loudness can be affected by various factors, including the distance from the sound source and how sound waves interact with the environment. Understanding intensity is critical in both noise control and environmental health contexts, as it helps in assessing potential impact on human health and well-being in various settings.

The other options, while related to sound, do not specifically relate to loudness. Nature of the noise refers to the characteristics or type of noise, frequency pertains to how high or low a sound is perceived (pitch), and exposed duration addresses how long someone is exposed to a sound, which can affect hearing over time but does not define how loud the sound is.