Evolution characteristics of PM2.5 in Zhenjiang Port based on EEMD-MFDFA
（1. School of Safety and Environmental Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China; 2. Zhenjiang Port Group Co., Ltd., Zhenjiang, Jiangsu 212001, China)
Abstract：To quantitatively analyze the internal evolution characteristics of PM2.5 time series in Zhenjiang Port, taking 205 667 PM2.5 hour concentration series in Zhenjiang port from 2019 to 2020 as basic data, the multifractal detrended fluctuation analysis（MFDFA）method based on ensemble empirical mode decomposition（EEMD）was used. The results show that the evolution of PM2.5 concentration at each monitoring point has significant long-term persistence characteristics. The rise of PM2.5 concentration at present stage may lead to the rise of PM2.5 concentration in the future. The multifractal spectrum parameters of PM2.5 concentration at different monitoring points are different. Areas with strong multifractal characteristics should be focused on immediate prevention and control, on the contrary, long-term supervision should be paid attention to. According to the theory of self-organized criticality, the fluctuation of PM2.5 concentration at 15 monitoring points presents the characteristics of power-law distribution, which is in line with the self-organized criticality.
郑敏学1， 毛静1， 孙智灏1， 朱龙1， 李志坚2， 居珍2， 黄爱国2. 基于EEMD-MFDFA的镇江港PM2.5演化特征分析[J]. 江苏大学学报（自然科学版）, 2023, 44(6): 738-744.
ZHENG Minxue1， MAO Jing1， SUN Zhihao1， ZHU Long1， LI Zhijian2， JU Zhen2， HUANG Aiguo2. Evolution characteristics of PM2.5 in Zhenjiang Port based on EEMD-MFDFA
[J]. Journal of Jiangsu University(Natural Science Eidtion)
, 2023, 44(6): 738-744.
ZHANG X X.Zhenjiang port: build a green model of port economy and run out of the "acceleration" of strong industrial city against the trend[J].Public Investment Guide,2020(28):3-5.（in Chinese）
DONG D M,DU S S,HUANG Y S,et al.Pollution cha-racteristics and source apportionment of PM2.5 in winter and spring in Changchun city[J].Journal of Jilin University(Science Edition), 2020,58(5):1278-1286.（in Chinese）
XIE H L,HE H D.Multifractal property between PM2.5 and PM10 in Hongkong port[J].Journal of Atmospheric and Environmental Optics,2019,14(3):179-190.（in Chinese）
［4］
WANG Q Z.Multifractal characterization of air polluted time series in China[J].Physica A: Statistical Mecha-nics and its Applications,DOI: 10.1016/j.physa.2018.09.065.
［5］
ZHANG C,WANG X F,CHEN S B,et al.A study on daily PM2.5 concentrations in Hong Kong using the EMD-based MFDFA method[J].Physica A: Statistical Mechanics and its Applications,DOI: 10.1016/j.physa.2019.121182.
［6］
WU Z H, HUANG N E.Ensemble empirical mode decomposition: a noise-assisted data analysis method[J]. Advances in Adaptive Data Analysis,2009,1(1):1-41.
CAO J J,NA J M,TANG G A,et al.Method for noise removal of DEMs：a case study on terrain profile of loess shoulder line[J].Geography and Geo-Information Science,2017,33(2):12-18,127.（in Chinese）
［8］
AGBAZO M N, N′GOBI G K, ALAMOU E,et al.Assessing nonlinear dynamics and trends in precipitation by ensemble empirical mode decomposition (EEMD) and fractal approach in Benin Republic (West Africa)[J] .Complexity,DOI：10.1155/2021/3689397.
［9］
GMEZ-GMEZ J, CARMONA-CABEZAS R, ARIZA-VILLAVERDE A B, et al. Multifractal detrended fluctuation analysis of temperature in Spain (1960—2019)[J]. Physica A: Statistical Mechanics and its Applications, DOI:10.1016/j.physa.2021.126118.
SHI C, REN Y, TANG H S，et al.Fault diagnosis of hydraulic valve based on improved MF-DFA and random forest[J].Journal of Chongqing University of Technology(Natural Science),2021,35(6):280-288.（in Chinese）
SUN S Z, HAN Y, DANG X Y，et al.Research on mo-deling and compensation for embedded angular displacement sensor dynamic measurement errors[J].Journal of Chongqing University of Technology(Natural Science),2022,36(3):78-85.（in Chinese）
GUO C J,LI D C,RONG F,et al. An improved EEMD method based on maximal correlation wave form exten-sion[J].Journal of Chongqing University of Posts and Telecommunications(Natural Science Edition),2017,29(6):768-775. （in Chinese）
DU J,LIU C Q,HUANG H L,et al.Multiscale EEMD decomposition of PM2.5 in Chengdu during winter and self-organized criticality of air pollution[J].Environmental Science and Technology,2019,42(8):133-141.（in Chinese）
［14］
LIU D,XIAO Z H,HU X,et al.Feature extraction of rotor fault based on EEMD and curve code[J].Measurement,DOI:10.1016/j.measurement.2018.12.009.
FENG Y,HUANG X D,CHEN J,et al.EEMD-PCA based denosing method for non-stationary vibration signals of large-size slewing bearings[J].Journal of Nanjing Tech University(Natural Science Edition),2015,37(3):61-66. （in Chinese）
［16］
ZHANG X K,ZHANG G,QIU L,et al.A modified multifractal detrended fluctuation analysis (MFDFA) approach for multifractal analysis of precipitation in Dongting Lake Basin, China[J].Water,DOI:10.3390/w11050891.
WU B, LIU C Q, ZHANG J,et al.Nonlinear dynamic mechanism of regional high air pollution during COVID-19 lockdown[J]. China Environmental Science,2021,41(5):2028-2039.（in Chinese）
