Noise pollution measure – UGC NET Question

Noise pollution refers to unwanted or harmful sound in the environment. Sound intensity is measured on a logarithmic scale called the decibel scale. Environmental and occupational standards specify safe limits in decibels for different settings. Therefore, decibel (dB) is the correct unit used for noise levels.

Option A:
Option A is incorrect because parts per million are used for concentrations of gases or solutes, not for sound. Air pollutants like SO₂ or NO₂ may be reported in ppm.

Option B:
Option B is correct as decibel is the standard unit for sound intensity. It allows comparison of noise levels from different sources on a common scale.

Option C:
Option C is incorrect since hertz measures frequency, not loudness. Frequency describes pitch, while decibels indicate intensity.

Option D:
Option D is incorrect because lumen is a unit of luminous flux used in lighting, not sound. It is relevant to visual, not auditory, pollution.