An analysis of relationships among environmental noise, annoyance and sensitivity to noise, and the consequences for health and sleep.

The complex relationship among long-term exposure to environmental noise, self-reports of health, and sleep was investigated in a multifactorial design. Forty-seven women and 35 men living beside a street with moderate to heavy traffic took part. They answered questions concerning health complaints, usual sleep patterns, sleep the actual week of testing, their subjective responses to noise, psychosocial relations, anxiety, stressful life events, type A behavior, and attitudinal factors that could explain their responses to noise. No detrimental relations among objective noise levels, health, and sleep could be shown. There were, however, strong correlations between the subjective noise responses of annoyance and sensitivity and health complaints. Only women revealed a relationship between poor sleep quality and sensitivity. The stronger relationship among noise sensitivity, health complaints, and poor sleep quality for women than for men could be explained by the degree of exposure to noise as evidenced by their longer residence and greater time spent at home.

Intensity-time tradeoff for constant hearing loss with high sound levels.

The tradeoff relation between exposure intensity and duration for constant hearing loss was investigated in two series of experiments using Mongolian gerbils. The gerbils were exposed to a 1/3 octave band of noise at 2.5 kHz. In the first series animals were exposed to 120 dB SPL for 1 h, to 126 dB SPL for 15 min, and to 126 dB SPL for 3.75 min. In the second series, shorter durations were used: 120 dB SPL for 15 min, 126 dB SPL for 3.75 min, and 126 dB SPL for 56 s. The hearing thresholds were determined behaviorally immediately before exposure and 6 weeks after exposure. The results suggest that the intensity-time tradeoff for the investigated intensity interval is between 1.5 and 3 dB per halving of the duration.