According to the WHO, which statement best defines health-relevant noise?

• A. Noise is a sound above 90 dB
• B. Noise is a pleasant sound
• C. Noise is every unpleasant and undesirable sound, which disturbs sleep and causes various disorders and reduced working capacity
• D. Noise is only occupational

Answer: (C)

Health-relevant noise refers to sounds that can affect health, not just how loud a sound is. It includes unpleasant and undesirable noise that disturbs sleep and can lead to various disorders and reduced working capacity. This framing emphasizes the health consequences of noise exposure, covering impacts like sleep disturbance, stress, and impaired performance, and it applies to both environmental and occupational sources as described by WHO. The other options don’t fit: simply using a loudness threshold omits health effects and context; a pleasant sound is the opposite of health-relevant noise; and restricting to occupational noise ignores environmental sources that also harm health.