Environmental Noise

Environmental Noise -- How it Hurts Us, and How We Can Silence It
By Murray Stacy

Although its presence lingered unaddressed for many years, environmental noise is now recognized as a significant health issue. Environmental or ambient noise is unwanted or harmful outdoor sound created by human activities, including noise emitted by means of transport - road traffic, rail traffic, air traffic - and from sites of industrial activity. From delivery trucks to air conditioners, we are constantly bombarded by sounds that go unnoticed for the most part. However, out-of-earshot should not mean out-of-mind. It is precisely these innocuous environmental noises that should be sounding an alarm.

Those involved with the more obvious noise sources such as airports, shooting sports, manufacturing or even musical concerts have long known the detrimental effect of extreme noise levels on long-term hearing. Only recently, however, has environmental noise been thoroughly researched for its affect on our mental and physical health – and the findings may surprise you. But to gain a better understanding, one needs a basic education on what, exactly, noise is.

Noise intensity is measured in decibel units. The decibel scale is logarithmic; each 10-decibel increase represents a tenfold increase in noise intensity. Human perception of loudness also conforms to a logarithmic scale; a 10-decibel increase is perceived as roughly a doubling of loudness. Thus, 30 decibels is 10 times more intense than 20 decibels and sounds twice as loud; 40 decibels is 100 times more intense than 20 and sounds 4 times as loud; 80 decibels is 1 million times more intense than 20 and sounds 64 times as loud. Distance diminishes the effective decibel level reaching the ear. Thus, moderate auto traffic at a distance of 100 ft (30 m) rates about 50 decibels. To a driver with a car window open or a pedestrian on the sidewalk, the same traffic rates about 70 decibels; that is, it sounds 4 times louder. At a distance of 2,000 ft (600 m), the noise of a jet takeoff reaches about 110 decibels—approximately the same as an automobile horn only 3 ft (1 m) away. ¹