竹東空氣品質測站的PM2.5研究

Abstract

本研究利用便攜式顆粒物在線監測儀(APM-2, Air Pollution Monitor 2)、裝設濾紙動態量測系統之錐狀震盪微量天秤(tapered element oscillating microbalance with filter dynamic measurement system, TEOM-FDMS)、半自動氣膠OC/EC分析儀(Semi-Continuous OC-EC Field Analyzer, Model-4)、液膜微粒採樣器(Particle into Liquid Sampler, PILS)監測竹東測站之大氣之PM2.5、OC、EC與水溶性離子之質量濃度。採樣時間為2014/9/9-11/14與2015/2/2-4/13。APM-2與TEOM-FDMS以及測站貝他監測計(Beta attenuation mass monitor, BAM)之PM2.5比對結果顯示其準確性良好，APM-2與TEOM-FDMS及BAM之R2分別為0.97與0.95，斜率分別為0.89與0.90。 分析春秋兩季竹東PM2.5及其成分濃度隨時間變化趨勢，推測竹東地區交通排放對PM2.5貢獻較大，且主要依據交通繁忙程度而變化。污染物來自於東北方向之西北東南走向快速道路。 分析採樣項目各成分濃度可知竹東PM2.5中水溶性離子成分主要為SO42-、NH4+及NO3-，而以SO42-為最多，在秋季占PM2.5的比例為32.6 ± 11.2 %，而春季則為26.8 ± 6.6 %，推測PM2.5中水溶性微粒主要為(NH4)2SO4。本研究所監測的離子、有機物質及元素碳質量濃度占PM2.5之比例分別為72.1 ± 17.8 %(秋季)與75.2 ± 21.0 %(春季)。

In this study, two real-time measurement monitors, APM-2(Air Pollution Monitor 2, Comde-Derenda GmbH, Germany) and TEOM-FDMS(tapered element oscillating microbalance with filter dynamic measurement system) were deployed at Zhudong air monitoring station in order to measure the PM2.5 mass concentrations. At the same time, a Semi-Continuous OC-EC Field Analyzer(Model-4, Sunset laboratory, USA), and a PILS(Particle into Liquid Sampler) were used to analyze the organic carbon, element carbon, and water soluble ions. This study consisted of two study periods: 2014/9/9-2014/11/14(fall) and 2015/2/2-2015/4/13(spring). The accuracy of APM-2 was validated by comparing its daily average PM2.5 concentrations with TEOM-FDMS data. Results showed good correlations between these two monitors. The liner regression slope and R2 were 0.89 and 0.97, respectively. Comparing the daily average PM2.5 concentrations of APM-2 with those of the BAM(Beta attenuation mass monitor), which is the PM2.5 monitor in Taiwan air monitoring stations, showed that the liner regression slope was 0.90 and R2 was 0.95. Concluding from the real-time monitoring data, the major contribution of PM2.5 was found to be vehicle emissions and secondary aerosols. The main component of ion was SO42-, NH4+and NO3- in which SO42- was the major component of PM2.5 with the percentage of 32.6±11.2% in fall and 26.8±6.6% in spring. Organic carbon and NH4+ each accounted for about one tenth of PM2.5 in both seasons. All of the measured ions, EC and OM accounted for 72.1 ± 17.8 % (fall) and 75.2 ± 21.0 % (spring) of PM2.5.