The hourly pH data from an automatic, sequential precipitation collector at a site in the Taipei Metropolatin Area from 1988 has been analyzed for this study. In these three years 70% of the pH values were less than 5. In 1986, 8% wereless than 4, but a teodency toward less acidity from 1986 to 1988 was evident. The hydrogen ion concentration deduced from the pH is found to be highest in the summer and secondly in the spring. The concentration in winter is the lowest. The pH seasonal variation is similar to that found in the northeastem United States by other investigators. Shower and thunderstorm precipitation types in summer are particularly acidic. The precipitation associated with typhoons in the summef and the north-eastem monsoon in the winter are less acidic. Typical weather patterns associated with two cases of low pH and two cases of high pH were also presented here too. Results suggested that long range transport of pollutants from mainland China may influence the pH in the Taipei area quite a lot. However more thoughful studies including observations and modelling are needed. 本研究旨在分析設置於台北地區的一處酸雨自動監測站所量測1986至1988年三年雨水逐時pH值。分析結果顯示三年平均約70%的降水pH值低於5.0，在1986年更有80%的雨水pH值低於4.0。就季節而言，夏季雨水最酸，其次為春季，以冬季雨水最不酸，此種pH值之季變化與美國東北各州類似。降雨型態以夏季午後陣雨最酸，而以夏秋季的颱風雨及冬季的東北季風雨較不酸。本文亦選擇最酸雨水和最鹼雨水分別作個案分析，結果顯示大陸之污染物可能經長距離輸送而影響台北地區雨木pH值，然仍需做更多研究包括觀測及模擬以為佐證。
