Noise Pollution and its Effects Quiz

Characteristics of Sound

• Sound is not a substance that can accumulate in the environment like other pollutants.
• It is measured in a unit called the 'Decibel' (dB).

Decibel Levels of Common Sounds

• Threshold of hearing: 0 dB
• Rustle of leaves: 10 dB
• Broadcasting studio: 20 dB
• Bedroom at night: 30 dB
• Library: 40 dB
• Quiet office: 50 dB
• Conversational speech (at 1m): 60 dB
• Average radio: 70 dB
• Light traffic noise: 74 dB
• Subway train: 90 dB
• Symphony orchestra: 100 dB
• Rock band: 110 dB
• Aircraft takeoff: 120 dB
• Threshold of pain: 146 dB

Effects of Noise Pollution on Physical Health

• Exposure to high sound levels can cause physical damage to the ear and temporary or permanent hearing loss.
• Temporary hearing loss is often called a temporary threshold shift (TTS).
• People suffering from TTS are unable to detect weak sounds, but hearing ability is usually recovered within a month of exposure.
• Permanent loss, called noise induced permanent threshold shift (NIPTS), represents a loss of hearing ability from which there is no recovery.
• Exposure to 95 dBA for 8 hours every day for over a period of 10 years may cause about 15 dBA of NIPTS.
• Noise can also cause harmful effects on the circulatory system by raising blood pressure and altering pulse rates.

Effects of Noise Pollution on Mental Health

• Noise can cause emotional or psychological effects such as irritability, anxiety, and stress.
• Lack of concentration and mental fatigue are significant health effects of noise.
• Noise can interfere with normal auditory communication, mask auditory warning signals, and increase the rate of accidents, especially in industries.
• It can also lead to lowered worker efficiency and productivity and higher accident rates on the job.

Permitted Noise Levels

• Silent Zone: 50 dB (day-time), 40 dB (night-time)
• Residential Zone: 55 dB (day-time), 45 dB (night-time)
• Commercial Zone: 65 dB (day-time), 55 dB (night-time)
• Industrial Zone: 70 dB (day-time), 70 dB (night-time)

Safe Time Limit for Exposure to Noise

• A standard safe time limit has been set for exposure to various noise levels.
• Beyond this 'safe' time, continuing exposure over a period of a year will lead to hearing loss.
• Below a sound level of 80 dBA, hearing loss does not occur at all.
• However, temporary effects are noticed at sound levels between 80 and 130 dBA.

Sources of Noise Pollution

• Outdoor noise pollution: factories, vehicles, playing of loudspeakers during festivals
• Indoor noise pollution: loudly played radio or music systems, and other electronic gadgets
• Noise generated by firecrackers is much higher than the prescribed levels (125 decibels, as per the Environment (Protection) (second amendment) Rules, 1999).