Chemical Characteristics and Source Apportionment of PM2.5 in the Industrial Complex of Southern Kaohsiung

Autor: Po-Hung Cheng, 鄭柏宏
Rok vydání: 2019
Druh dokumentu: 學位論文 ; thesis
Popis: 107
Air pollutants are accumulated in southern Kaohsiung due to intensively distributed heavy industries in this area, causing heavy environmental loading. Poor air quality in southern Kaohsiung has been lasted for a long period of time mainly due to topographical and meteorological conditions. In highly polluted season, PM2.5 concentration was commonly higher than ambient air quality standard (35 μg/m3) in southern Kaohsiung. PM2.5 has a serious impacts on atmospheric visibility, ecological environment, and human health. It has been criticized by general publics and environmental groups, and is also paid attention by central and local environmental protection agencies. Accordingly, this study aims to conduct the sampling of PM2.5 in four seasons. PM2.5 samples were collected simultaneously at ten sampling sites (Linhai and Linyuan Industrial Complex) from December 2017 to September 2018. After sampling, PM2.5 filters were conditioned, weighed, and chemical analyzed (water-soluble ions, metallic elements, carbonaceous contents, anhydrosugars, and organic acids) for characterizing the fingerprint of PM2.5 by using different indicators (eg: SOR, NOR, NR, SOC, OC/EC, M/S). Furthermore, enrichment factor (EF), backward trajectory simulation, principal component analysis (PCA), and chemical mass balance (CMB) were then combined and further applied to identify the potential sources of PM2.5 and their contributions. Field sampling results showed that high concentrations of PM2.5 were observed mainly in late fall, winter, and spring, and commonly presented as nighttime > daytime. The variation of water-soluble ions during the PM2.5 episodes was consistent with PM2.5 concentration, ranging from 31.4 to 56.8%. Secondary inorganic aerosols (SIA) (SO42-+NO3- +NH4+) were dominated by water-soluble ions (WSI). The ratios of SIA/PM2.5 were generally higher in winter and spring than those in summer and fall, suggesting that PM2.5 was highly affected by secondary aerosols. The percentages of metallic elements in PM2.5 ranged from 12.0 to 20.2% in which metallic elements (Al, Ca, Mg, K, Fe) were commonly presented as Lihai > Linyuan, and mostly presented as daytime > nighttime. The enrichment factor (EF) showed that the toxic metals (Ni and Cr) came from anthropogenic sources (ie. heavy oil boilers and petrochemical plants). Moreover, carbonaceous content accounted for 9.3-24.3% in PM2.5, and the mass ratios of organic and elemental carbons (OC/EC) were the highest mainly in winter and spring, indicating that more secondary aerosols formed in these two seasons. The average concentrations of levoglucose ranged from 8.1 to 74.8 ng/m3. The mass ratios of malonic and succinic acid (M/S) were always higher than 1.0 in winter and spring, while lower than 1.0 in summer and fall, indicating that organic acids were the major contributor to secondary organic aerosols (SOA) in winter and spring. The ratios of NR, NOR, and SOR showed that PM2.5 was mainly acidic particles in all seasons since NR < 1, while NOR > 0.1 and SOR > 0.25 showed that SIA were mostly occurred in winter and spring. This study also used (OC/EC)min to estimate the concentration of secondary organic carbon (SOC). The results showed that SOC could be observed in all seasons. and increased significantly in fall, winter, and spring. Results obtained from PCA and CMB receptor modeling showed that the major sources of PM2.5 in Linhai industrial complex were steel plants, and followed by mobile sources and petrochemical plants, while the major sources of PM2.5 in Linyuan industrial complex were petrochemical plants, and followed by mobile sources and fugitive dusts. The results indicated that Linhai and Linyuan industrial complexes were mainly affected by metal processing industries, and the contributions of SIA in the polluted seasons were generally higher than other seasons.
Databáze: Networked Digital Library of Theses & Dissertations
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