Correlation and scaling behaviors of fine particulate matter (PM_2.5) concentration in China

Air pollution has become a major issue and caused widespread environmental and health problems. Aerosols or particulate matters are an important component of the atmosphere and can transport under complex meteorological conditions. Based on the data of PM _2.5 observations, we develop a network approach to study and quantify their spreading and diffusion patterns. We calculate cross-correlation functions of the time lag between sites within different seasons. The probability distribution of correlation changes with season. It is found that the probability distributions in four seasons can be scaled into one scaling function with averages and standard deviations of correlation. This seasonal scaling behavior indicates that there is the same mechanism behind correlations of PM _2.5 concentration in different seasons. Further, the weighted degrees reveal the strongest correlations of PM _2.5 concentration in winter and in the North China Plain for the positive correlation pattern that is mainly caused by the transport of PM _2.5. These directional degrees show net influences of PM _2.5 along Gobi and inner Mongolia, the North China Plain, Central China, and Yangtze River Delta. The negative correlation pattern could be related to the large-scale atmospheric waves.