A novel ensemble back-propagation neural network approach will be developed and implemented to estimate the spatial concentration of NO2 over East Asia. The long-term trend, as well as the high concentration hotspots of NO2, will be analyzed carefully based on the generated spatial map of NO2. We expect to quantify the emission control impacts over different countries on the NO2 ambient concentration from the long-term perspective. The student should seek the course instructor's approval to take this course.