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

Abstract

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 PM₁₀, SO₂, and NO₂ in Hangzhou, China, with a conduction time of 30 hours; this effect is non-existent between PM_2.5 and O₃. In addition, there is a unidirectional fractal fluctuation conduction between PM_2.5 and CO with a conduction time of 21 hours.