ZHANG Yong1,2 , CHEN Zhuo3，CHEN Rongxiang1,2 ，BAO Yuxin1,2 ,YANG Ming1,2

(1.Analytical and Testing Center, Zunyi Medical University, Zunyi, 563000, China; 

2.Research Center for physical and chemical analysis and testing engineering technology, Zunyi, 563000, China 

3. College of Chemistry and Material Science, Guizhou Normal University, Guiyang, 550001, China )

Abstract：To explore the diurnal pollution characteristics and sources of water soluble ions in Zunyi, PM2.5 samples were continuously collected during daytime (08:00-19:30) and nighttime (20:00-07:30) from October 2020 to January 2021.The samples were detected for contents of 8 water-soluble ions, and diurnal variations characteristics were analyzed. Then principal component analysis-multiple linear regression (PCA-MLR) modeling were performed for water-soluble ions sources apportionment. The results show that the average concentration of water-soluble ions in Zunyi City were 16.89±9.29 μg/m3 during the sampling period,the water soluble ions concentrations exhibited obvious seasonal variation, with higher levels in winter than in autumn. The concentrations of NO3-, NH4+, K+, and Cl- in nighttime were higher than that in the daytime, while SO42-, Ca2+ and Mg2+ were higher in daytime. The secondary ions(NH4+, NO3-, SO42-) were dominant water soluble ions in Zunyi City , accounting for 81.9% of total ions mass concentration in autumn and 86.8% in winter. The ratios of diurnal AE/CE were less than 1, indicating that the PM2.5 was alkaline in Zunyi City. NH4+ mainly existed in the form of (NH4)2SO4 and NH4NO3 in particulate matter. The PCA-MLR model indicated that the mainly sources of water soluble ions in PM2.5 of Zunyi City were secondary sources (61.86%), dust(19.64%), coal and biomass burning(18.50%).

Key words：Zunyi City; water-soluble ions; PM2.5; diurnal characteristics

EARTH AND ENVIRONMENT Vol.51, No.1, Tot No.351, 2023, Page 9