Question

Sounds above what level are considered hazardous noise pollution?

• A. above 80 dB
• B. above 30 dB
• C. above 150 dB
• D. above 120 dB.

Answer 1

The Correct Option is A

The question asks about the decibel (dB) level above which sounds are considered hazardous noise pollution. Let's explore this further:

Sound levels are measured in decibels (dB). The decibel scale is logarithmic, which means that every increase of 10 dB represents a tenfold increase in intensity. Here are some common reference points on this scale:

• 0 dB: The faintest sound that the average human ear can hear.
• 30 dB: A quiet library or a soft whisper.
• 60 dB: Normal conversation.
• 80 dB: Busy city traffic or a noisy restaurant.
• 100 dB: Factory machinery or an approaching subway train.
• 120 dB: Threshold of discomfort, such as loud concerts.
• 150 dB: A jet engine at takeoff.

According to occupational health guidelines, exposure to sound levels above 80 dB can be hazardous over extended periods and may result in hearing damage or noise-induced hearing loss. This is because prolonged exposure to noise at or above this level can lead to damage of the hair cells in the ear, which are vital for hearing.

Conclusion: Therefore, the correct answer is that sounds above 80 \, \text{dB} are considered hazardous noise pollution.

Why Other Options Are Incorrect:

• 30 \, \text{dB}: This represents a very quiet sound, such as a whisper, which is not harmful.
• 150 \, \text{dB}: While this is indeed hazardous and more immediately harmful, it doesn't set the standard threshold for "hazardous noise pollution," which starts at lower levels.
• 120 \, \text{dB}: This level is very high and can instantly cause pain but is not the threshold for starting hazardous levels as defined by health standards.