Occupational noise is one of the occupational health problems; furthermore, it is one of worldwide environment hazards. To effectively control the occupational noise could not only conserve the hearing, health and well-being of workers, but also could eliminate hidden dangers to assure the production safety. Based on the analysis of the severity of the occupational noise problem and the significance and urgency in controlling this hazard in China, the cause of occupational noise is analyzed by the system en...