Study on spatiotemporal distribution of the tropospheric NO2 column concentration in China and its relationship to energy consumption based on the time-series data from 2005 to 2013

The spatial and temporal distribution of the tropospheric NO2 column concentration in China and its relationship with energy consumption were analyzed based on spatial analysis and Grey Relation using the remote sensed data from 2005 to 2013. The results show that the spatial distribution of NO2 in China shows close relationships with population distribution and terrain properties. NO2 distribution is divided into the eastern and the western part by HU Line, a geographical division line of the population of China. The NO2 concentration is on the rise in most provincial-level regions, but has remained stable in a few provincial-level regions over a long period. In general, China’s NO2 concentration reached its peak approximately in 2011. During the years from 2005 to 2010, China’s NO2 concentration grew rapidly and reached its peak in 2011, following with a steady growth or a slight decline during the years 2011 to 2013. There shows a U-shaped variation in monthly NO2 concentration, with the highest NO2 concentration in winter and spring, lower one in the summer, and a distinct increase in autumn, which demonstrates a seasonal variation of NO2 concentration. At a national-scale, the NO2 concentration distribution shows a strong positive correlation with the total coal and oil consumption per unit area, implying that the total coal and oil consumption contributes significantly to the NO2 concentration and should be controlled to reduce the NO2 concentration. In regions with a high NO2 concentration, the provincial-scale NO2 concentration is affected by the types of energy consumed, or to be more specific, is affected by the total coal consumption in northern China versus the total oil consumption in southern China, and by the total oil consumption in eastern China versus the total coal consumption in western China.