水氣之化學研究對於瞭解森林生態系的水文循環、養分循環及環境汙染機制非常重要。本研究使用先端致冷晶片技術製造一部採樣器，以臺灣大學實驗林鳳凰茶園為試驗地，大量收集霧天及晴天時空氣中水氣之冷凝水，進行水化學分析。分析項目包括pH值、電導度、陰離子 (SO42-、Cl-、NO3-、F-)及陽離子(NH4+、Na+、Ca2+、K+、Mg2+)的時序列變化。結果顯示所研發的採様器確實可以收集空氣中的水氣，並將之冷凝成水進行水化學分析。霧天時的pH值介於4.8至5.8之間平均為5.2，比晴天時的濃度為低，並且霧天時pH值介於5.0至5.5及5.0以下(酸雨）的出現機率分別為88%及6%。在霧天與晴天時陽離子濃度大小依序為NH4+>Na+>Ca2+>K+>Mg2+。在霧天與晴天時pH值、電導度、陽離子及陰離子濃度進行P值檢定分析之後，顯示兩者之間有顯著的差異。霧天空氣中水氣的水化學研究需要更多的野外觀測資料與統計分析，才能進一歩的證實並提供未來森林生態系的水文循環、養分循環及環境汙染研究的參考。

Aqueous vapor chemistry research is very important for understanding of hydrological cycle in forest ecosystem, nutrient cycling, and environmental pollution mechanism. This study has developed an efficient collector with advanced cooling technology. The water vapor in the fog and sunny day was cooled to condense water for water chemistry analysis and comparative studies. Experimental site was selected in Fenghuang tea garden for sequencing analysis of hourly pH value, conductivity, anions (SO42 、Cl-、 NO3-、F-) and cations (NH4+、Na+、Ca2+、K+、Mg2+). The collector worked well. The average pH value is 5.2 and in the range of 4.8 to 5.8 that indicates a tendency towards acid rain in tea garden. The pH value in fog day is significantly lower than the sunny day. In fog day, the distributions of pH value of 5.0-5.5 and less 5.0 (acid rain) are 88% and 6% respectively. The concentration of cation in the aqueous vapor shows the rank: NH4+>Na+>Ca2+>K+>Mg2+. Furthermore, there are significant differences on the pH value, conductivity, anion, and cationan concentration between fog and sunny days.