Assessment volume of environment noise SNL, CNL and their utilization

This paper analyses the relation between the human subjective sense and various environmental noise level indices. It conducts a comprehensive study of the correlation between different sound levels and subjective annoying rate based on the principle of applied mathematics and experimental psychology. Comprehensive indices in sound environmental assessment, SNL and CNL, are introduced. The psychological effect of sound on people, besides the isolated sound level indices, is counted as an assessment volume in environmental noise assessment so that the assessment index can directly reflect the psychologically acceptable limit of human to sound surroundings. This method of evaluation shows the percentage of people affected by noise under the sound surroundings. The author also gives a detailed description of the application of the assessment index to analysis and predicts sound environmental quality, as well as the description of its advantage and application on construction projects planning.