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108

19,150 千元

空氣品質監測

2019/01/11

2019/12/31

李崇德

監資處

黃健瑋

國立中央大學

環境監測及檢測

PM2.5化學成分監測、PM2.5化學成分時間與空間分布特徵、交通源PM2.5化學成分特徵、PM2.5有機化合物、推估PM2.5污染源及大氣能見度影響因子

PM2.5 chemical component monitoring, Temporal and spatial distributions of PM2.5 chemical characteristics, PM2.5 chemical characteristics in traffic sources, PM2.5 organic compounds, PM2.5 source apportionment and atmospheric visibility influencing factors

王家麟；周崇光；張士昱；蕭大智；許文昌；莊銘棟

黃秋華

03-4226551#

cilia0110@gmail.com

本計畫進行2019年1月到11月於環保署板橋、忠明、斗六、嘉義、小港及花蓮測站每6天1次例行採樣，此外，還進行復興與三重測站的交通源採樣以及斗六測站的有機物採樣。例行和交通源採樣樣本分析PM2.5水溶性無機離子、碳成分、金屬元素等化學成分，有機物樣本以半定量方法解析。所分析的PM2.5化學成分(外加2018年12月)，配合監測站空品數據、環境因子以及相關模式模擬等資料，本計畫用來探討PM2.5質量濃度與化學成分時間與空間分布特性、解析高濃度事件特徵、並推估可能污染來源。 結果顯示，各季節不同測站間PM2.5質量濃度變化，除夏季外，呈現由東至北再向南遞增的趨勢，2019年花蓮和板橋站PM2.5濃度以春季為最高，忠明、斗六、嘉義與小港站則以冬季為最高，近三年各測站PM2.5季節濃度變化有明顯下降趨勢，但也出現減緩訊號。各季節測站間PM2.5化學成分多以硫酸根離子(SO42-)與有機碳(OC)為主，但冬季斗六、嘉義、小港站則是以硝酸根離子(NO3-)為主要化學成分。金屬元素濃度與PM2.5質量濃度空間分布變化相近，小港站金屬元素總濃度、各元素濃度或占比大多最高，但花蓮站元素Tl、忠明站元素Zr、嘉義站元素K、Ba、Pb、As及Ga為各站濃度或占比最高。PM2.5揮發性水溶性離子Cl-與NO3-於夏、秋兩季揮發比例較高，NH4+季節變化穩定。石英濾紙吸附的碳成分正干擾變化較穩定，微粒碳成分揮發的負干擾則較有變化。交通源採樣，復興站和鄰近小港站PM2.5濃度和化學成分相近，三重站化學成分以碳成分的OC1、EC1-OP及EC2與金屬元素的Ba、Cu、Sb及Zr較鄰近板橋站相對差異百分比高。在斗六站24個樣本有機物分析發現塑化劑與阻燃劑物質是重要成分，可能來自塑膠材料風化碎裂、焚化過程受熱裂解揮發等過程。 PM2.5高濃度事件日(≧35 μg m-3)環境特徵，在前夜有低風速時發生機率最高；但當環境有前夜污染殘留特徵時，當日為事件日的機率最高。六站中，PM2.5高濃度事件日在板橋、忠明及小港站以NOx與CO增益較SO2顯著，斗六與嘉義站則是SO2增益較其他各測站為明顯。事件日的NO3-較非事件日(< 35 μg m-3)在PM2.5濃度占比增加約11%。分析各站含氮物質氧化率(Nitrogen Oxidation Ratio, NOR)，發現斗六與嘉義站事件日NOR值是六站間最大，採樣日過剩NO3-發生頻率由中部向南遞增，都顯示台灣中部以南的NOx前驅氣體充足。 以PMF (positive matrix factorization)受體模式解析近三年數據，各站可得9項污染源因子，「硫酸鹽」、「硝酸鹽」為前二高貢獻因子。板橋、忠明、嘉義及花蓮站以「硫酸鹽」因子為主，顯示區域污染傳輸影響程度大；斗六及小港站則是「硝酸鹽」，表示在地污染衍生物影響程度大。各地區「車輛排放」普遍為第二或第三高貢獻因子，較不受地區與季節影響，近三年各站貢獻比例多有上升。以PM2.5化學成分、氣體污染物、相對濕度代入修正的IMPROVE方程式推估大氣消光係數(bext)，結果以硫酸鹽對bext貢獻最為明顯，但冬季斗六、嘉義及小港站受硝酸鹽影響居多，推估的bext與板橋、忠明、小港站實測的bext有不錯相關性；同樣地，在能見度統計廻歸分析中，SO42-是各站都具有顯著性的PM2.5化學成分。最後，在PM2.5化學成分採樣檢測經驗與最新技術方面，本計畫完成彙整31篇。

PM2.5化學成分監測、PM2.5化學成分時間與空間分布特徵、交通源PM2.5化學成分特徵、PM2.5有機化合物、推估PM2.5污染源及大氣能見度影響因子

108年度細懸浮微粒(PM2.5)化學成分監測及分析計畫.pdf

38MB

2020/7/1 上午 12:00:00

This study proceeded with regular collections of PM2.5 (aerodynamic diameters equal to or smaller than 2.5 μm) at the Banqiao, Zhongming, Douliu, Chiayi, Xiaogang, and Hualien air quality monitoring sites of Environmental Protection Administration in Taiwan every six days from January to November 2019. In addition, PM2.5 collected at the Fuxing and Sanchong sites for traffic source investigation and the Douliu site for organic compound resolution. PM2.5 mass, water-soluble inorganic ions, carbonaceous contents, and metal elements were resolved plus a semi-quantitative resolution of organic compounds for further analysis. This study investigated the characteristics of temporal and spatial distributions of PM2.5 mass and chemical components (with additional data of December 2018), high concentration events, and potential source contributions by utilizing the analyzed PM2.5 chemical components, air quality monitoring data, environmental factors, and the corresponding model simulation products. The results showed that seasonal PM2.5 mass levels increased in the order from east, north, to the south of Taiwan during the sampling period except summer. The highest seasonal PM2.5 mass levels at the Hualien and Banqiao sites were in spring, while that of the Zhongming, Douliu, Chiayi, and Xiaogang sites were in winter. The trends of seasonal PM2.5 mass levels in the recent three years were mostly downward but with a sign of leveling off. In general, SO42- and organic carbon were the two most abundant components at all sites for all seasons except NO3- at the Douliu, Chiayi, and Xiaogang sites in winter. The spatial distribution of metal elements varied with PM2.5 mass levels accordingly. The total metal elemental concentrations, individual metal elemental concentrations, or metal elemental fractions of PM2.5 were frequently the highest at the Xiaogang site. However, the concentrations or fractions of metal elements Tl at the Hualien site, Zr at the Zhongming site, and K, Ba, Pb, As, and Ga at the Chiayi site were the highest among the six sites. The volatilizations of NO3- and Cl- were higher in summer and autumn, while NH4+ was relatively stable across seasons. Meanwhile, positive interferences of volatilized organic carbons adsorbed by quartz-fiber filters varied less than negative interferences from the volatilization of the collected carbonaceous particles. For the traffic source collection, PM2.5 mass levels and chemical components were similar at the Fuxing and the nearby Xiaogang site. In contrast, the relative percentage differences of OC1, EC1-OP, and EC2 of carbonaceous contents, and Ba, Cu, Sb, and Zr of metal elements were significant between the Sanchong and the nearby Banqiao sites. The organic compounds resolved from 24 samples collected at the Douliu site revealed that plasticizers and fire retardants were major components and potentially contributed from emissions of weathered plastic materials and thermal pyrolysis volatilization during combustion. During the sampling period, the environmental characteristic of high PM2.5 concentration events (≧ 35 μg m-3) was with the highest probability for low wind speed in the previous night. In contrast, pollution leftover in the previous night was with the highest probability for the occurrence of high PM2.5 concentration events on the day. Moreover, high PM2.5 concentration events were with more NOx and CO enhancements than SO2 at the Banqiao, Zhongming, and Xiaogang sites, while SO2 enhancement was more evident at the Douliu and Chiayi than the other sites. The percentage increase of NO3- in PM2.5 was 11%, comparing high PM2.5 concentration events with non-event PM2.5 levels (< 35 μg m-3). The analysis of Nitrogen Oxidation Ratio (NOR) showed that the NOR value of high PM2.5 event days in the Douliu and Chiayi sites was the highest among the six sites. The frequencies of excess NO3- in the event days increased from central to south, indicating the abundance of precursor NOx southward of central Taiwan. For source apportionment using positive matrix factorization (PMF), “sulfate” and “nitrate” were the two most significant factors in the nine resolved source factors at all sites. The factor of “sulfate” was dominant at the Banqiao, Zhongming, Chiayi, and Hualien sites implying regional pollution transport mattered, while the dominance of “nitrate” at the Douliu and Xiaogang sites indicating derivatives from local pollution in control. “Vehicle emissions” less influenced by areas and season, contributed secondly or thirdly at all sites, and increased steadily in the recent three years. For estimating the atmospheric light extinction coefficient (bext), this study inserted PM2.5 chemical components, gas pollutants, and relative humidity into the revised Interagency Monitoring of Protected Visual Environments (IMPROVE) equation. Sulfate contributed bext significantly among all chemical components at all sites in all seasons except nitrate at the Douliu, Chiayi, and Xiaogang sites in winter. The estimated and measured bext values were with moderately high correlations at the Banqiao, Zhongming, and Xiaogang sites. Similarly, SO42- was the significant factor in influencing atmospheric visibility from the statistical regression analysis. Finally, this study reviewed 31 works of literature in the most recent techniques of collection and measurement of PM2.5 chemical components.

PM2.5 chemical component monitoring, Temporal and spatial distributions of PM2.5 chemical characteristics, PM2.5 chemical characteristics in traffic sources, PM2.5 organic compounds, PM2.5 source apportionment and atmospheric visibility influencing factors