Dynamic Changing Analysis Of Regional Environmental Risk At Different Time Scales

Environmental risk problem has received increasing attention because of a growing number of environmental disasters. Environmental disasters and incidents are damaging the natural environment, threaten personal safety and impacting the social and economical development. Environmental risk assessment is a valid way to avoid risk accidents. Accurate and reasonable assessment results are the basis of risk management decisions. How to make the forecasts of the societal risk value of accidents more reliable? How to identify space distribution relationship under different time scales of risk sources and risk receptors (here refers to the population) in regional developing process? How to avoid regional environmental risk more effectively? The above questions have become core problems need to be resolved in environmental risk assessment.The study used the ZY-3high-resolution remote sensing image and GIS to simulate the population spatial distribution data at daytime of workdays, daytime of non-workdays and nighttime of Dalian development zone Dagushan peninsula for2004and2012. Hot spot analysis, change detection, integral population center and accumulation area population center transference analysis were carried out around the population spatial distribution change under different time scales (yearly, weekly, daily). The risk sources positioning and the parameter determination were based on the remote sensing image. Then, the changing rule was analyzed under different time scales. This paper used the epoxy ethane tank and methanol tank leakage accident in Qihua area of Dagushan industrial park as an example. This study simulated the accident scene and calculated the individual risk and societal risk value. Then, the environmental risk change was figured out during the regional population density changing.The results showed as follows.(1) Maqiaozi Street was the hot spot area of Dalian development zone Dagushan peninsula from2004to2012. The number of population was increased at the daytime of workdays while was decreased at the daytime and nighttime of non-workday in industrial park, and the number of population was increased in the northwest adjacent sea area at nighttime.The population center moved to the southeast direction at the daytime of workdays; the integral population center moved to the northwest direction at both the daytime and nighttime of workdays; the integral population center of accumulation area moved to the north by east direction at the daytime of workdays and non-workdays; the accumulation area population center moved to south by west direction at nighttime.(2) For both2004and2012, Xingang area was the hot spot area of Dagushan industrial park. The Main change areas were Xingang oil storage area and Dalian LNG storage tank area. The center of risk sources moved to the southeast direction. Neighbor relationships between risk source and risk receptor showed a trend of increase.(3) For the leakage accident of Dalian Qihua area, the risk value was at a low level during the day and nighttime in2004, and the individual risk contour was also at a negligible level. While in2012, during the daytime and nighttime,10-6a-1individual risk contour went into parts of industrial area and Cuixin residential areas, and the risk was at an unacceptable level. The societal risk values were at negligible levels in2004, while parts of the accident social risk curve were at unacceptable levels in2012at the daytime of workdays, the daytime and nighttime of non-workdays, which signified that risk management was needed for risk reduction.