Noise Pollution

Noise Pollution Overview

1. Noise Pollution: Overview

Definition:

Noise pollution is the spread of loud, unwanted sounds that disrupt the activities of humans and animals, often causing harm.

⚠️ Exam Important:

  • • Exposure to noise pollution adversely affects the physiological health of a person.
  • • Exposure to noise pollution adversely affects the psychological health of a person.
  • • Average noise levels in heavy traffic zones in major cities in India are generally in 70-95 dBA ranges of noise levels.

The primary culprits of outdoor noise worldwide are machines, transportation, and various systems of propagation. Poor urban planning can also contribute to noise pollution.

2. Noise Measurement Parameters

Researchers measure noise using three key parameters: pressure, intensity, and frequency.

1. Sound Pressure Level (SPL)

SPL helps determine how loud a sound is by comparing it to the threshold of hearing.

⚠️ Exam Fact: Sound pressure of 20µPa (micropascals) corresponds to a noise of zero decibel.

2. Sound Intensity

Measured in Watts per square meter.

⚠️ Exam Fact: Two sounds of same intensity but different frequency characteristics may appear to be of different loudness.

3. Frequency

Measured in Hertz (Hz). Humans can hear frequencies ranging from 20 Hz to 20,000 Hz.

⚠️ Exam Fact: The response of the human ear to noise of different frequencies is not uniform.

Factors Influencing Impact:

The impact of noise pollution on human health is governed by:

  • Intensity of noise
  • Duration of noise
  • Sensitivity of human ear
  • Frequency range of noise

3. Decibel (dB) Levels & Regulations

Noise above 65 dB is classified as pollution by WHO.

Decibel Scale of Common Sources

Office 50 dB Conversation 60 dB Street Corner 80 dB Highway 90 dB Jet Take-off 140 dB

⚠️ Exam Important (Sequence):

The correct sequence of average noise levels in increasing order:

Typical office → Conversational speech → City Street corner → Highway → Aircraft noise during take-off

🇮🇳 Noise Standards in India (2000 Rules)

🏫 Educational Institutions

Night time (10pm-6am) limit:

40 dB

🏡 Residential Areas

Day time limit:

55 dB

4. Health Effects

Exam Summary:

Exposure to excessive noise pollution can cause:

  • Hearing impairment
  • Insomnia (Sleeplessness)
  • Rise in blood pressure (Hypertension)
  • Reduced work efficiency
  • Speech interference
  • Shift in threshold of hearing

Systemic Impacts of Noise

Psychological Stress Hearing Loss Hypertension (BP) Sleep Disturbance

🫀 Cardiovascular

High noise levels can lead to cardiovascular problems and hypertension.

🦁 Wildlife

Disrupts predator/prey detection and reproduction.

🏠 Real Estate

Local noise environment impacts property value.

5. Mitigation

How to block noise?

⚠️ Exam Important: Materials with high surface/mass density act as good noise barriers.