Asymmetric MF-DCCA Method Based on Fluctuation Conduction and its Application in Air Pollution in Hangzhou

The study of the relationship between the concentration of PM 2.5 and the local air quality index (AQI) is significant for the improvement of urban air quality. This study not only considered multifractal cross-correlation but also the fluctuation conduction mechanism. An asymmetric multifractal detrended cross-correlation analysis (MF-DCCA) method based on fluctuation conduction is introduced here to empirically explore the causality and conduction time between air quality factors and PM 2.5 concentration. The empirical results indicate the existence of a bidirectional fluctuation conduction effect between PM 2.5 and PM 10 , SO 2 , and NO 2 in Hangzhou, China, with a conduction time of 30 hours; this effect is non-existent between PM 2.5 and O 3 . In addition, there is a unidirectional fractal fluctuation conduction between PM 2.5 and CO with a conduction time of 21 hours.