Noise Pollution

1. Hearing
The mechanism for chronic exposure to noise leading to hearing loss is well established. The elevated sound levels cause trauma to the cochlear structure in the inner ear, which gives rise to irreversible hearing loss. The pinna (visible portion of the human ear) combined with the middle ear amplifies sound levels by a factor of 20 when sound reaches the inner ear.

Cardiovascular health
High noise levels can contribute to cardiovascular effects and exposure to moderately high (e.g. above 70 dBA) levels during a single eight hour period causes a statistical rise in blood pressure of five to ten mmHg; a clear and measurable increase in stress [1]; and vasoconstriction leading to the increased blood pressure noted above as well as to increased incidence of coronary artery disease.

Annoyance
Though it pales in comparison to the health effects noted above, noise pollution constitutes a significant factor of annoyance and distraction in modern artificial environments:

a.The meaning listeners attribute to the sound influences annoyance, so that, if listeners dislike the noise content, they are annoyed. What is music to one is noise to another.

b.If the sound causes activity interference, noise is more likely to annoy (for example, sleep disturbance)

c.If listeners feel they can control the noise source, the less likely the noise will be annoying.

d.If listeners believe that the noise is subject to third-party control, including police, but control has failed, they are more annoyed.

e.The inherent unpleasantness of the sound causes annoyance.

f.Contextual sound. If the sound is appropriate for the activity it is in context. If one is at a race track the noise is in context and the psychological effects are absent. If one is at an outdoor picnic the race track noise will produce adverse psychological and physical effects.

2.a.transportation noise
b.office equipment:factory machinery, appliances, power tools, lighting hum and audio entertainment systems
c.Recreational vehicles

3. Same as (1)

4.a.Roadway noise is the most widespread environmental component of noise pollution worldwide. There are a variety of effective strategies for mitigating adverse sound levels including: use of noise barriers, limitation of vehicle speeds, alteration of roadway surface texture, limitation of heavy duty vehicles, use of traffic controls that smooth vehicle flow to reduce braking and acceleration, innovative tire design and other methods. Thousands of case studies in the U.S. alone have been documented starting in 1970, indicating substantial improvement in roadway planning and design. The most important factor in applying these strategies is a computer model for roadway noise, that is capable of addressing local topography, meteorology, traffic operations and hypothetical mitigation. Costs of building in mitigation is often quite modest, provided these solutions are sought in the planning stage of a roadway project.

b..Exposure of Industrial noise on workers has the longest history of scientific study, having been addressed since the 1930s. This scientific studies have emphasized redesign of industrial equipment, shock mounting assemblies and physical barriers in the workplace. Innovations have had considerable success; however, the costs of retrofitting existing systems is often rather high.

Too detail

我都要做，比你:

Noise Pollution is a serious problem.Therefore, the government should ,

Causes:

．heavy traffic

．roadworks

．construction

Effests:

．difficult for us to work or relax

．make us sick

Solution:

．government ought to reduce construction

．people ought not to sing loundy at night