Tomorrow's noise will be more disturbing and crueler than today's, for two reasons. First, we are increasing the number of noise sources and saturating the entire environment. Second, we are becoming sensitized to noise.
From England comes this observation from a Senior Lecturer in Acoustics at the University of Liverpool:
"Our reactions at a particular instant depend among other factors on our noise history; we are also becoming more noise conscious... We have a tendency to create more noise and a growing awareness of noise."
We may be becoming less tolerant because, as some authorities believe, noise assault is cumulative and the threshold of sensitivity is lowered with increased exposure.
We have not yet begun to cope with the noisy bus and truck and jet, and already we are extending the welcome mat to new intrusive noise sources. When rivers become aviation runways and the space over center-city is nothing but elevator shafts for helicopters and escalator space for STOLs, city-man is going to feel he is living in the center of the Iron Maiden. Not to mention the sonic boom carpet to be thrown over people not living near the large metropolitan center (to be discussed in detail in Chapter 5).