Noise Pollution (p1) Flashcards
(29 cards)
What are sounds?
Sounds are vibrations that pass through matter (solids, liquids, and gases)
Sound vibrations cannot pass through a vacuum.
Define noise.
Noise is unwanted sounds that disturb or can cause damage.
What is the impact of noise on human health?
Noise can lead to deafness, tinnitus, stress, communication problems, and other health issues.
What is the logarithmic dB scale?
The dB scale shows sound power levels; an increase of 10dB represents a 10x increase in volume.
What is the threshold for human hearing?
0dB is the quietest sound that can be heard at 1000 Hz.
What is the typical frequency range of human hearing?
The typical range is 20 – 20,000 Hz.
What can excessive noise exposure lead to?
It can reduce sensitivity and range of hearing.
List some effects of noise pollution on humans.
- Deafness
- Tinnitus
- Stress
- Communication problems
- Headaches
- Irritability
How can noise pollution affect livestock?
It can cause injury or miscarriage.
What impact does noise pollution have on wildlife?
It may disturb breeding, reduce feeding success, and cause hearing damage or behavioral changes.
What is acoustic fatigue?
It occurs when repetitive vibrations at the resonant frequency cause cracking and structural failure.
How can military aircraft contribute to noise pollution?
Low-level training flights cause noise pollution in rural areas.
How can military aircraft noise pollution be minimized?
- Informing farmers of flight schedules
- Avoiding urban areas
- Varying flight paths
- Requesting temporary stops for events
What are some strategies for reducing noise pollution from civil aircraft to a residential area?
- Building airports away from residential areas
- Acoustic insulation for housing
- Noise deflection with baffle mounds
What are high-bypass ratio engines?
Engines designed to reduce noise by forcing bypass air around the inner cowling.
What are chevron nozzles used for?
They mix bypass air with surrounding air more smoothly to reduce noise.
What is a blended wing aircraft?
An aircraft design where engines are located on top of the aircraft to reduce ground noise.
What is the purpose of constant descent angles in flight paths?
To reduce noise during landing by minimizing periods of high thrust.
What are noise limits for aircraft?
Aircraft are categorized by noise levels, with older noisier aircraft banned from certain airports.
What does the quota count system do?
It allocates points to aircraft based on their noise levels, encouraging quieter planes.
List some ways to control road traffic noise.
- Quieter engines
- Sound-absorbing materials on roads
- Improved vehicle aerodynamics
- Planting trees along roads
How can railway noise be controlled?
- Track polishing
- Sound-absorbing suspension
- Lubrication for wheels
- Composite braking materials
What is industrial noise caused by?
Impact between metal objects or explosive expansion of gases.
Name some methods to control industrial noise.
- Sound absorbing surfaces
- Acoustic curtains
- Machinery on acoustic mats
- Worker ear protection
