二氧化硫 (SO2) 是極具植物毒性之空氣污染物之一。本研究為探討二氧化硫對植物影響，選用五種常見之行道樹，苗木高度約60~90公分，分別以600、1000及2000 ppb之二氧化硫進行48小時熏氣試驗，藉以評估其對二氧化硫抗耐性表現。測定試驗樹種熏氣前後之光合作用率及空氣污染抗耐指數等參數，分析植物熏氣後生理變化，並探討熏氣後植物葉面受損情況。結果顯示，二氧化硫於濃度2000 ppb時植物受損情形較600ppb、1000 ppb時嚴重，除青剛櫟，有較高的淨光合作用率，大葉山欖樹只有熏氣前之8%，山芙蓉、黃槿、珊瑚樹熏氣後皆死亡，且熏氣濃度愈高，植物葉面病徵愈明顯。

Sulfur dioxide (SO2) is one of the most toxic air pollutants for plants. In this study, we chose five common roadside tree varieties to study the influence of sulfur dioxide on plants. The seedlings used were about
60~90 cm in height, and were fumigated with 600 ppb, 1000 ppb and 2000 ppb sulfur dioxide, respectively,for 48 hours to evaluate the
susceptibility to sulfur dioxide of these plants. After sulfur dioxide treatment,physiological changes and damages on leaves were detected by comparing the photosynthetic rates and air pollutant tolerant index (APTI) before and after sulfur dioxide treatment. Compared to 600 ppb and 1000 ppb sulfur dioxide, the results showed that 2000 ppb sulfur dioxide caused the most damage on plants. Except Quercus glauca Thunb. Ex Murrray, which maintained 79% of the net photosynthetic rate, Palaquium
formosanum Haytata displayed only 8% of the original photosynthetic rate while Hibiscus taiwanensis Hu,Hibiscus tiliaceus L. and Viburnum odoratissimum Ker. were all dead after treatment. In addition, the higher
the sulfur dioxide concentration, the more the damages on the leaves.