Atmospheric PM_(2.5) near an Urban-Industrial Complex during Air-pollution Episodes with Various Meteorological Conditions

Sheng-Lun Lin ； Yunzhou Deng ； Chien-Er Huang ； Kun-Kuo Tien ； Yen-Yi Lee

《Aerosol and Air Quality Research》 22卷8期 (2022/08) Pp. 1-17+ap1-021

https://doi.org/10.4209/aaqr.220187

摘要

This study investigates the atmospheric fine particulate matter (PM_(2.5)) issue caused by the multi-effect of complicated sources, terrain, and meteorology at Southern Taiwan. Three sampling stations represent an urban, a rural, and a coastal sites near an urban-industrial complex. The atmospheric PM_(2.5) were measured during a pollution episode from November to February, when the reference samples were collected in April. The sample was collected with a constant-flow sampler with the Federal Reference Method performance. After determining the PM_(2.5) mass, their chemical compositions of ions, metals, and carbons were analyzed for the different properties caused by the multi-factors. The chemical mass balance (CMB) model was employed to evaluate the emission contributions. Additionally, an inverse trajectory model is used to analyze the pollutant transport and support the CMB results. The air-pollution episodes occurred within the winter to spring. The PM_(2.5) were composed of 51-69% ions, 18-31% carbonaceous species, and 1.5-3.0% metals. The SO_4^(2-), NH_4^+, and NO_3^- contributed 92-96% of the ions. Most of the organic/elemental carbon ratios were low, suggesting more primary carbon emissions. The metal contents were minor and dominated by Fe and Zn. The CMB model indicated the PM_(2.5) were dominated by 24% secondary SO_4^(2-), 14.7% traffics, 8.3% petrochemical emissions, 6.8% soil dust, and 4.5% sintering plant emission. For non-episode days, the PM_(2.5) were contributed by 34.9% traffics, 30% the secondary SO_4^(2-), 10.3% secondary NO_3^-, and 6.8% soil dust. Nevertheless, the frequent sea-land breeze might lead to more powerful wind eddies and bring the primary PM_(2.5) and the aerosol precursors from the emission areas. Consequently, the uncontrollable meteorological changings would lead to the pollution issues at the lowly convective area. Therefore, the averaging emissions of the PM_(2.5) and precursors should be lowered; meanwhile, the rapid controls of the primary emissions are suggested when the high-level PM_(2.5) are forecasted.

關鍵字

PM_(2.5) ； Monsoon ； Wind eddies ； Chemical composition ； Source apportionment