Measurement, Experiment And Evaluation On Main Light Pollutions From Urban Lighting

Urban night landscape lighting, as an important part in the urban environment,plays good roles in creating a city night image and improving the night life quality. However, not all lightings can achieve such results. Lightings that have adverse influences on human, animals, plants and city environment are light pollutions. Similar to water pollution and air pollution, light pollution is not conducive to sustainable development of cities. In recent years, light pollution, one of new global environment problems, has been paid special attention by international academe circles.Several main light pollutions were investigated in this thesis, such as sky glow, spill light, dynamic obtrusive light and so on, by four research methods, namely site measurement, laboratory simulation, mathematical statistics and neural network prediction method. Further, through theoretical studies, survey, measurement and evaluation analysis, technology indexes and evaluation procedures of light pollution were preliminarily proposed for establishment of a complete set of light pollution prevention and inspection system.Main innovative results are as following:1. This thesis compared and analyzed the night sky brightness in Tianjin at typical weather conditions,different time,different directions and different angles on the basis of continual measurements. The distribution model and rules of the city night sky brightness were investigated firstly. Influencing factors, measurement methods and assessment processes on the night sky brightness were preliminarily discussed.2. The night sky brightness distribution shows a nonlinear and time-varying information structure. The BP neural network was firstly applied to urban night sky brightness prediction. An improved BP algorithm with measurement data as training samples was introduced to train the network by MATLAB software and the relative error was within 4.0 percent.3. The orthogonal design method was used in light pollution study and its advantage is to significantly reduce test times. Influences of setting factors of searchlights on sky glow and the changes with every factor level were quantitatively analyzed. 4. From the perspective of environmental psychology, this thesis firstly simulated dynamic light environment in the laboratory and researched influences of combination and intersection of three factors (namely background brightness, distance/solid angle and stimulating speed) on visual perception. Further, the quantitative analyses were carried on from background, gender and time attributes by statistical methods with a view to guidance for the design optimization on dynamic lighting in a city and theory discussion for establishment of standards and regulations.5. Two kinds of light pollution evaluation procedures, six overall evaluation indexes and seven detection technology indexes were initially proposed from the aspects of urban night-lighting planning and light pollution forms.