| dc.description.abstract | This study collaborated with the “2017 PM2.5 chemical composition monitoring and analysis study” to resolve characteristics, seasonal variations, and pollution sources of PM2.5 metal elements from manual and automatic monitoring at the Mailiao, Yunlin County (Winter) and Dacheng, Changhua County (Spring, Summer, Autumn) in 2017.
The results showed that PM2.5 mass concentrations varied from high to low in the order of Autumn> Winter> Spring> Summer. The predominant metal elements in mass concentration are Al, Fe, Na, Mg, K, Ca, and Pb. Related sources of these metal elements can be derived from local traffic emissions, sea salt, steel manufacturing plant within Formosa Plastics Corporation, and coal-fired power plants of the neighboring Sixth Naphtha Cracker Complex (SNCC). The enrichment factors of metal elements could be as high as 100 folds for Cu, Zn, Mo, Cd, Pb, Sb, Se, Sn, and Tl. The potential sources were traffic emissions, coal combustion, metal processing, zinc metallurgy, and oil combustion. In addition, the crustal element Igeo indices for Cu, Zn, Sn, Pb, V, Zn, Pb, V, and Ni were greater than one indicating moderate polluting at least. Potential sources were traffic emissions, coal combustion, joss paper burning, and metal processing.
PMF (Positive Matrix Factorization, PMF) source apportionment showed that “Oil combustion”, “Ship emissions”, “Sea-salt”, “Fossil fuel combustion”, “Industrial mixed sources”, and “Petrochemical industry” were predominant sources at the Mailiao and Dacheng areas. Combining with the conditional bivariate probability function for source orientation, this study showed that “Oil combustion” and “Ship emissions” had the highest probability in spring. The “Oil combustion” might be from the West Coast Expressway, and “Ship emissions” could be transported from farther northern sea waters. “Fossil fuel combustion” might be influenced by the West Coast Expressway with the highest proportion in spring. In contrast, the “petrochemical industry” was transported from the SNCC and had the highest proportion in summer.
Finally, this study compared four source inference methods to find that PMF was the only method to apportion source contributions quantitatively. | en_US |