Environmental Noise Control Quiz

Control of Environmental Noise

• Noise is defined as unwanted or undesirable sound.
• Community noise involves noise levels inside dwellings, mainly from traffic.
• Intense noise in workplaces (factories, etc.) can cause permanent physical damage.
• Noise exposure leads to harmful physiological effects like hypertension, annoyance, sleep disturbance, and hearing loss.

Levels of Noise

• Sound level (L) is measured in Bels (B) or decibels (dB)
• L = log10(Q/Q0) (B), where Q is the measured sound pressure, sound power, or intensity, Q0 is the reference standard quantity
• L = 10 log10(Q/Q0) (dB) is the more common expression, convenient for practical use
• A safe noise level in a city is considered as 45 dB by WHO.
• A noise level of 65 dB is considered tolerable according to international standards

The Nature of Sound

• Sound is the sensation caused by a vibrating medium on the ear.
• Vibrations in solids, gases (air), and liquids generate sound waves.
• Sound waves are longitudinal, consisting of successive compressions and rarefactions of molecules.

Sensitivity of Sound

• People can hear frequencies between roughly 20Hz to 20,000 Hz (subjective factors can apply)
• The lowest intensity perceived as sound is 10^-12 W/m² (threshold of audibility)
• An intensity of 1 W/m² is the threshold of pain, potentially damaging to the ear.

Effects of Noise

• Noise effects vary with level, exposure time, and health conditions.

• 65 dB: annoyance, psychological effects

• 90 dB: potential for permanent hearing loss (repeated exposure)

• 100 dB: temporary impairment of hearing with short exposure; severe damage with repeated exposure

• 120 dB: pain, potential harm to many organs

• 150 dB: instant hearing loss

• Noise exposure can activate the sympathetic nervous system, impacting blood circulation, the brain, and other organs.

• It can affect hormone levels, reducing detoxifying functions in the liver, potentially causing stomach ulcers and allergies

• Long-term exposure can lead to circulatory diseases, abortion, and congenital defects.

Sleep Interference

• Noise can interrupt sleep, leading to short-temperedness, fatigue, and reduced efficiency the next day.

Effect on Working Efficiency

• Noise decreases working efficiency.
• Noise reduction methods like better soundproofing or barrier design can improve worker performance and safety (reduced accidents).

Effect on Wildlife

• Noise harms wildlife—making them dull and impacting breeding in some species.
• Migratory birds and larger animals are susceptible.

Effects on Non-Living Things

• High noise levels can damage buildings (cracks, weakened foundations, loosened plaster).
• Noise can also harm household items.

Control of Noise Pollution

• Noise cannot be entirely eliminated but can be reduced through different methods
• Controlling the source of the noise via machinery modification
• Preventing sound transmission through barriers or increasing distance between the source and receiver.
• Using noise-absorbing materials.
• Personal protective gear (earplugs, etc) and reduced usage times or locations of potentially harmful noise activities.

Other Ways of Noise Control

• Formulating noise regulations for equipment and locations
• Educating the public on hazards and awareness development

Review Questions

• (Note: The document provides various multiple-choice-like questions needing answers beyond a simple summary)

Test your knowledge on the control of environmental noise and its effects on health. This quiz covers topics such as noise levels, measurements in decibels, and the nature of sound. Understand the implications of noise exposure in communities and workplaces.