Noise pollution refers to undesirable levels of noises caused by human activity that disrupt the standard of living in the affected area. It comes from traffic, airports, railroads, manufacturing plants, construction or demolition, concerts, etc.
Some noise pollution may be temporary while other sources are permanent. The effects may include hearing loss, wildlife disturbances, and a general degradation of lifestyle. A persistent noisy environment can cause annoyance, irritability, headache, sleeplessness and may seriously affect the productive performance of human.
Types of noises based on frequencies
- Ultrasonic (> 20,000 Hz)
- Sonic (20-20,000 Hz) [It can be heard by human]
- Subsonic (< 20 Hz)
The unit of sound is measured in Sound Pressure Level (SPL) and common unit of measurement is Decibel (dB) or dB(A). SPL is weighted with respect to a scale known as sound level meter, that is why it is denoted with unit dB(A).
Noise level can range from 0 to more than 120 dB, at which point physical discomfort starts. Desirable decibel of sounds for different areas:
| Zones | Day (6.00 – 2100 hr) | Night (21.00 – 6.00 hr) |
| Industry
Commercial Residential Silent zone |
75 dB
65 dB 55 dB 50 dB |
70 dB
55 dB 45 dB 40 dB |
How to Control Noise Pollution
- Sound proof doors and windows.
- Factories and industries should be located far from the residential area.
- Planting trees and bushes around sound generating sources.
- Regular servicing and tuning of automobiles can effectively reduce noise pollution.
