What unit is used to measure the relative loudness of sound?

The unit used to measure the relative loudness of sound is the decibel. Decibels express sound intensity on a logarithmic scale, allowing for a meaningful comparison of sound levels, as human perception of sound is also logarithmic. This means that an increase of 10 decibels represents a tenfold increase in sound intensity, which aligns with how we perceive changes in volume.

In practical terms, the decibel scale is ideal for describing the wide range of sounds we encounter, from soft whispers to loud noises, making it particularly useful in fields such as noise control, audio engineering, and safety management in environments where sound levels may pose a risk. Measurements in decibels can help assess the potential impact of noise exposure on hearing health, ensuring that appropriate protective measures are implemented in high-noise environments, such as confined spaces where rescuers may operate.