Detrended cross-correlation analysis of temperature, rainfall, PM10 and ambient dioxins in Hong Kong

Using detrended cross-correlation analysis (DCCA), we investigate the long-term influence of some factors, specifically precipitation, average temperature and PM10 concentrations on the evolution of Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) concentrations in Hong Kong. The 15 years regular monitoring data from two general urban sites, Central/Western District and Tsuen Wan, are analyzed. The results show that the relationships between ambient dioxins and precipitation (or PM10) display long-term cross-correlation at the time scale ranging from one month to one year; while, no cross-correlation with each other have observed in longer temporal scaling regimes (greater than one year). Meantime, differentiated from the previous study, we found that precipitation has the greatest influence on ambient PCDD/PCDFs at the long-term time scaling (about one year) in Hong Kong. And no significant relationships are found between ambient dioxins and average temperature at long-term time scale. These results correspond to atmospheric circulation and regional transport hypothesis and are explained in detail. The long-term cross-correlation property is discussed further, considering the strong influence of the Asian monsoon system.