Noise as a Source of Environmental Annoyance

1. In recent years more attention has been given to noise and unwanted sound as another form of environmental disturbance. Excessive noise has been a part of the industrial environment for a long time — motors, metal presses, drills and heavy machinery of all types have made many factories a din of hoise since the beginning of the industrial revolution. Now, however, the public at large is subjected to increasing noise from traffic, airplanes, construction, urban crowding and we are now aware of much of this sound as a new irritant and source of environmental annoyance, Sound energy is usually measured in terms of decibels, one decibel being approximately equal to the threshold of hearing in man. A 10-fold in­crease in sound adds 10 units to the decibel scale and a 100-fold increase in sound adds 20 units. In a typical urban environment, background noise in a quiet sound-protected room generally runs 40 decibels while ordinary street noises average 70 to 80 decibels.

Lesson 22 <► 217

2. Around the home, background noise averages 40 to 50 decibels, conversation produces 60 decibels, a garbage disposal 85 and a vacuum cleaner 90 decibels. Heavy city traffic at rush hour usually produces 95 to 100 decibels, and a jet aircraft taking off generates 120 to 150 decibels.

3. Medical science has recently shown that excessive noise can be a significant nervous stress. It can increase irritability and reduce job effi­ciency. In some cases it can cause changes in heart rate, blood pressure, and metabolism similar to other types of emotional anxiety and stress. Prolonged noise, above the level of 95 decibels, can also cause hearing loss and early deafness. Workers in noisy factories, construction trades and transportation jobs which have high noise levels are especially sub­ject to hearing loss.

4. A special and controversial aspect of noise pollution is the advent supersonic aircraft. They will produce «sonic booms», loud and forceful reverberations of air as the planes pass overhead. Critics of supersonic planes feel that this will be an intolerable source of sound — a new stress (hat will cost more in human irritation than it will be worth in reduced transportation times. The proponents of supersonic transportation feel lhat this is nonsense — that man will adjust to this new technologic advance as readily as he adjusted to the light bulb and motor car. Such a controversy provides another example of the difficulty of assessing the lull impact of rapidly advancing technology on the health of man and l he quality of our environment.

Упражнение 4. Просмотрите текст А и скажите, в чем трудность предотв­ращения шума.

Упражнение 5. Найдите в тексте А ответы на следующие вопросы.

1. Why has noise and unwanted sound been given more attention to? 2. What are the examples of sound disturbances measured in decibels? \. What are the consequences of excessive noise as environmental dis­turbance? 4. What do critics of supersonic planes say? 5. Can man adjust to this new technologic advance?

Упражнение 6. Переведите письменно абзац 4 текста А

Упражнение 7. Составьте письменно аннотацию текста А.

218 ♦ Learning to Understand a Medical Text

Упражнение 8. Прочтите следующие тексты. Найдите в них придаточные предложения и переведите их.