Spatiotemporal trends in PM2.5 levels from 2013 to 2017 and regional demarcations for joint prevention and control of atmospheric pollution in China

A complex network correlation model was established and used to demarcate highly inter-correlated regions within China based on long-term and massive data mining of PM2.5 concentration, and seven major regions, including Beijing-Tianjin-Hebei and surrounding areas, Yangtze River Delta, Chengdu-Chongqing, Lanzhou-Xining urban agglomeration, South China, Central China, and Northeast China, were identified. These results provide a scientific basis for formulating long-term, stable, and unified JPCAP strategies for China and implementation of JPCAP measures that focus on the specific problems of each region. Network diagram of the PM2.5 correlation coefficients for the 31 provinces in China. (a): P ≥ 0; (b): P ≥ 0.6; (c): P ≥ 0.7; (d): P ≥ 0.75.203