二元酸是大氣環境中氣膠的重要組成之一，來自石化燃料燃燒及人為與生物源的有機前驅物的光化反應導致。二元酸的存在會改變氣膠在大氣中的尺寸及雲凝結的成核反應，進而影響降雨及氣候，已有證據指出因二元酸會折射來自太陽輻射而直接及間接影響地球的輻射平衡，從而抗衡因溫室氣體導致的全球暖化現象。然而目前對於微粒二元酸的形成及微粒粒徑分布的相關研究，國內外尚少瞭解，本計畫將分兩年採集不同時節，代表台灣背景地區森林針葉林植物物種五葉松及代表地表郊區針葉林植物物種南洋杉植物，以瞭解針葉林植物物種之二元酸排放特性及二元酸物種比例，藉以探討針葉植物對大氣二元酸形成之貢獻。 Dicarboxylic acids, which originate from burning of petroleum fuel as well as from man-made and natural photochemical precursors, are one of the important atmospheric aerosols. Their existence in the atmosphere will change the size and chemical reactions of cloud condensation nuclei (CCN) to influence precipitation and climate. There are also evidences showing that dicarboxylic acids will refract solar radiation thus directly or indirectly affect the global radiation balance to counterbalance the global warming caused by greenhouse gases. However, the formation and size distribution of fine dicarboxylic acids in the atmospheric particles have not been fully studied and understood by either native or international researchers. Hence, this two-year research will investigate emission potential of biosources of aerosol dicarboxylic acids in coniferous forest atmosphere. The plant species include Hayata and Lamb. The correlation between size distribution and photochemical environment for dicarboxylic acid aerosol in the different woods and the formation characteristics of nano dicarboxylic acids in the different woods will be investigated.