- 學位論文
新式現址空氣成分採樣器開發與應用
Application and development of the novel in situ air composition measuring equipment
摘要
本研究發展的新式現址空氣成分採樣器(The in situ Air Composition Measuring Equipment, ACME)，藉由可攜式且輕量化的設計成功與無人飛行器整合(Air Composition Measure Equipment + Unmanned Aircraft Vehicles, ACME-UAV)。ACME與FRM手動標準方法同步比對結果，總離子濃度的斜率與截距分別為1.0 與 -1.8 μg/ m3 (r = 0.94)；硫酸鹽、硝酸鹽及銨鹽的同步比對結果顯示斜率與截距分別為1.0與-0.3 μg/ m3(r = 0.96)、0.9與0.2 μg/ m3(r = 0.95)及1.1與-2.0 μg/ m3(r = 0.89)，ACME與FRM手動標準方法具有相似的濃度趨勢變化，在未受氣體吸附的干擾下，兩種方法的量測結果未達統計顯著差異。 ACME的逐時觀測可應用於污染變異大及高濕的環境，可藉由高時間解析的數據探討污染傳輸過程以及霧事件中氣相及氣膠的異相反應。研究期間顯示中國大陸沿海的下風區域易受到高濃度微粒污染影響，高相對濕度(80-85%)環境促進了非均相反應的發生，導致氣膠對能見度的影響顯著增加。而霧時期通過異相反應在2小時間可以觀測到SO2轉化為SO42-。另外，在霧發生期間若銨不足與氮氧化物反應成硝酸鹽類，此時大氣中氮氧化物以NOz為主 應用UAV穩定性及移動性，輔助ACME至各垂直高度進行氣膠樣品的收集。根據垂直大氣氣象、O3與氣膠光學的同步觀測結果顯示氣膠濃度垂直分布明顯受到物理條件影響，在鄰近高度間發生水平風速高低較大落差時，污染物濃度形成分層現象，穩定的大氣條件有利於二次氣膠的生成與累績。高相對濕度可促進污染物質的異相反應生成，同時潮解性氣膠離子的吸濕成長可能導致氣膠被散射訊號更加劇提高，且臭氧於相對濕度高的時期有助於氣膠的快速形成及轉化。由氣膠組成濃度-高度的分布觀測到NH4+與NO3-來源主要以區域性的交通污染為主，高濃度影響範圍在150 m以下的空間。而硫酸鹽分布於150 m以下的濃度趨勢變化與NH4+及NO3-相似，150 m以上的SO42-則與Na+、Cl-、K+及Ca2+的趨勢一致。顯示SO42-的兩種來源分別為低空的本地鄰近污染以及高空污染傳輸，其中高空污染傳輸的主要為工廠鍋爐或是煙囪排放的細粒徑氣膠，但高空中仍不排除有海鹽、塵土以及生質燃燒的貢獻。 整體而言，本研究所發展的新式現址空氣成分採樣器可應用於多變的大氣污染觀測，並且結合無人飛行器的採樣系統，可有效解析邊界層內的氣膠濃度垂直分佈，藉由氣膠化學特徵辨別污染來源。
並列摘要
The in situ Air Composition Measuring Equipment (ACME) developed in this study has been successfully integrated with UAVs by portable and lightweight design (Air Composition Measure Equipment + Unmanned Aircraft Vehicles, ACME-UAV). The ACME and FRM manual standard method comparison results showed that the slope and intercept of the total ion concentration were 1.0 and -1.8 μg/ m3 (r = 0.94), respectively; sulfate: 1.0 and -0.3 μg/ m3; nitrate: 0.9 and 0.2 μg/ m3; ammonium salt: 1.1 and -2.0μg/ m3. ACME has a similar concentrations trend changes to the FRM manual standard method. The measurement results of the two methods give nonsignificant differences when excluding the effects of acid/alkaline gas interference. The online ACME system has been applied to environments with high pollution and high humidity, and high-resolution data can be used to investigate the heterogeneous reaction of gas-phase and aerosol in the process of pollution transmission and fog events. During the study period, the downwind areas along the coast of China's mainland were vulnerable to high concentration of particulate pollution. High RH conditions (80~85%) promote the occurrence of heterogeneous reactions, resulting in a significant increase in the impact of aerosols on visibility. In the fog case, SO2 was converted to SO42- by a heterogeneous reaction in 2 hours. And there was no excess ammonia for a heterogeneous/homogeneous reaction to form the nitrogen oxides when ammonia-poor. The main component was the NOz when ammonia was limited. The ACME was carried by UAV to each vertical height for aerosol sample collection by the UAV stability and mobility. According to the simultaneous observations of vertical atmospheric meteorology, O3, and aerosol optics, the vertical distribution of aerosol concentration was affected by physical conditions. The speed of the horizontal wind speed between different heights causes the concentrations of pollutants to form a stratification phenomenon, and there was conducive to the formation and achievement of secondary aerosols under atmospheric stability conditions. High relative humidity promotes the formation of heterogeneous reactions of pollutants, and the hygroscopic growth of deliquescent aerosol ions may lead to a more dramatic increase in Backscattering Ratio signals, and ozone contributes to the rapid formation and conversion of aerosols during periods of high relative humidity. According to the vertical distribution of aerosol compositions, it is observed that the sources of NH4+ and NO3- were mainly from the regional traffic pollution, with high concentration affects space below 150 m. The concentration trend of sulfate distribution below 150 m was similar to that of NH4+ and NO3-, and SO42- above 150 m was consistent with the trends of Na+, Cl-, K+, and Ca2+. The two sources of SO42- were low-altitude local adjacent pollution and high-altitude pollution transmission, and the high-altitude pollution transmission is mainly the fine-grained portions from the factory boiler or chimney. However, there may still be contributions from sea salt, dust and biomass burning in the air. Overall, the novel in situ air composition measuring equipment developed in this study applied to variable atmospheric pollution observations. ACME-UAV effectively measures the vertical distribution of aerosol concentrations in the boundary layer and identifies the source of pollution by aerosol chemical characteristics.
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