| 摘要: | 氣膠是大氣中的重要成分並且也是影響氣候變遷的主因之一，其中黑
碳(Black carbon, BC)主要來源為化石燃料、生質燃燒等，有機碳(Organic
carbon, OC)則又可包含原生性有機碳(Primary organic carbon, POC)及衍生性
有機碳(Secondary organic carbon, SOC)，其中POC通常與BC具有相同的來源，
而SOC則為經由光化學反應後產生。鹿林山大氣背景監測站(Lulin
Atmospheric Background Station, LABS, 23.47°N, 120.87°E, 海拔高度2862 m)
為西太平洋北方以及東亞唯一的高山背景監測站，可作為區域背景大氣特
性之代表。本研究利用最小相關係數法(Minimum R Squared, MRS)，搭配氣
流軌跡的分析，探討鹿林山氣膠總碳質量濃度(Total carbon, TC)中POC、SOC
以及BC的分布變化，分析不同來源氣團的氣膠碳成分組成特性。
實驗觀測期間為 2021 年 8 月至 2024 年 7 月，結果顯示每年春季(3-5
月)東南亞生質燃燒所產生之氣膠，會藉由西風帶將污染物傳送至鹿林山，
導致春季時各碳成分的濃度達到季節性峰值，本研究依照後推軌跡推估資
料，分為 6 個不同的氣團來源，包括中國、西風帶、日韓、太平洋、南海以
及東南亞，其中以西風帶為最高 TC 濃度(1.57 μg/m3
)之來源，相比最低的太平洋來源氣團 TC 濃度(0.60 μg/m3
)高約 161%，而太平洋氣團中 SOC 所佔
的比例(35.1%)皆高於其他來源，東南亞來源氣團中 SOC 則佔最少之比例
(21.0%)，針對事件值與背景值分析的結果證明事件發生期間 PM2.5 中的碳
成分氣膠比例較高，且主要成分為 BC (26.0%)與 POC (50.5%)。
本研究為確定污染物的傳輸路徑與來源，利用潛在源貢獻因子法
(Potential Source Contribution Factor, PSCF) 結 合 濃 度 加 權 軌 跡 法
(Concentration Weighted Trajectory, CWT)的分析，探討潛在源的貢獻，其
PSCF 與 CWT 具有一致的結果，顯示影響 LABS 主要污染源來自西風帶與
東南亞地區，且於春季期間最為顯著，少部分 OC 來源來自中國的貢獻。
;Aerosols are an important component of the atmosphere and one of the main
factors affecting climate change. Among them, black carbon (BC) mainly
originates from fossil fuels and biomass burning, while organic carbon (OC) can
include primary organic carbon (POC) and secondary organic carbon (SOC). POC
usually shares the same sources as BC, whereas SOC is produced through
photochemical reactions. The Lulin Atmospheric Background Station (LABS;
2862 m) is the only high-altitude background monitoring station in East Asia,
representing the regional background atmospheric characteristics. This study
utilizes the Minimum R Squared (MRS) method combined with air mass
trajectory analysis to investigate the distribution variations of POC, SOC, and BC
in the total carbon (TC) mass concentration of aerosols at LABS. It analyzes the
composition characteristics of aerosol carbon components in different seasons and
from different air mass sources.
The observation period of this study spans from August 2021 to April 2024.
The results indicate that each spring (March-May), aerosols produced by biomass
burning in Southeast Asia are transported to LABS by the westerlies, causing
seasonal peaks in the concentrations of carbon components. BC and POC account
for the highest proportions of TC in spring. During the summer to autumn period,
the dominance of marine air masses leads to a significant reduction in pollutant
concentrations. Based on backward trajectory analysis, the study identifies six
different air mass sources: China, westerlies, Japan-Korea, Pacific Ocean, South
China Sea, and Southeast Asia. The westerlies are the source of the highest TC
concentration (1.57 μg/m3
), which is approximately 161% higher than the lowest
iv
TC concentration from the Pacific Ocean air mass source (0.60 μg/m3
). The
proportion of SOC in the Pacific Ocean air mass source (35.1%) is higher than in
other sources, while the Southeast Asia air mass source has the lowest proportion
of SOC (21.0%). The analysis of event and background values indicates that the
proportion of carbonaceous aerosols in PM2.5 is higher during events, with BC
(26.0%) and POC (50.5%) being the main components.
To determine the transport paths and sources of pollutants, this study uses
the Potential Source Contribution Factor (PSCF) combined with Concentration
Weighted Trajectory (CWT) analysis to investigate potential source contributions.
The consistent results of PSCF and CWT indicate that the main pollution sources
affecting LABS originate from the westerlies and Southeast Asia, with the most
significant impact during the spring. A smaller portion of OC comes from
contributions from China. |
