| 摘要: | 空氣品質影響民眾生活品質與健康的相關議題廣泛受到重視，促使本研究著手評估並比較1994及2004年台北市空氣品質之經濟價值。空氣品質為一非市場財貨，我們無法找到空氣品質的實際交易市場，以交易價格來衡量其經濟效益，因此使用特徵價格法（hedonic price method），以房屋交易市場為其替代市場，找尋空氣品質之價值。本研究以房屋價格作為應變數，影響房價的諸多因子為自變數，如空氣污染、屋齡、樓層數、至市中心距離、與捷運站距離及與公園綠地距離等，並且有些自變數必須經過特別處理，如以GIS arcview軟體來模擬台北市全面之懸浮微粒與總懸浮微粒濃度作為空氣污染變數。在估計特徵價格函數後，利用間接推估的方法衡量空氣污染經濟效益，找出民眾的願付價值（willingness to pay；WTP）。
本研究發現：（1）台北市空氣品質在2004年比1994年乾淨，空氣品質以懸浮微粒與總懸浮微粒濃度來看，有明顯的改善，且在2004年污染濃度低於政府規定之最低污染標準。（2）1994年最適特徵價格函數為半對數模型，2004年為雙邊對數模型。（3）總懸浮微粒濃度對房屋價格的影響有時間延遲，前二期總懸浮微粒濃度對房價之影響比當期更大。（4）1994年台北市總懸浮微粒濃度對房屋價格有顯著負向影響；懸浮微粒對房屋價格有負向影響，但不具顯著性。（5）2004年台北市懸浮微粒與總懸浮微粒對房屋價格有顯著負向的影響。（6）1994年民眾對於改善一單位（μg/m3）總懸浮微粒濃度之每戶願付價值為27,132元。（7）2004年民眾對於改善一單位（μg/m3）懸浮微粒及總懸浮微粒濃度之每戶願付價值，以當年價格表示，分別為90,765元及26,334元，以1994年價格表示之每戶實質願付價值分別為77,958元及22,617元。（8）雖然2004年空氣品質比十年前已明顯改善，但是從特徵價格函數的估計發現懸浮微粒濃度對房價的影響從1994年的〝影響不顯著〞，經過十年，已變成〝極為顯著的負向影響〞，可見民眾對空氣品質的要求愈來愈嚴格。（9）從總懸浮微粒的民眾邊際願付價值來看，即使十年來總懸浮微粒之污染已得到明顯改善，每戶之願付價值仍然維持在一個很高的水準（1994年27,132元，2004年26,334元），可見民眾對空氣品質的要求愈來愈嚴格。（10）假設空氣品質在2004年時，才由1994年空氣品質水準改善至2004年空氣品質水準，民眾願付價值（累積願付價值）分別為：懸浮微粒8,682,154元，總懸浮微粒3,560,706元。（11）將1994年空氣品質水準改善至2004年空氣品質水準的累積願付價值乘上2004年台北市總戶數923,325戶，可得民眾之總願付價值分別為：懸浮微粒80,164億元，總懸浮微粒32,877億元。
The air pollution problem in Taipei has been serious and the air pollution has influenced citizens' quality of life and health. This research was set about estimating and comparing economic values of air quality in Taipei in 1994 and 2004. Air quality is non-market goods, we can't find a real trade market of air quality for reflecting its economic benefits at the price of trade. This study used the hedonic price method, looking for a substitute market to find values of air quality. After estimating characteristic function, this study utilized the method to estimate indirectly its economic benefits. Among air pollutants, the particulate matters and suspending particles can be perceived by eyes. People are most directly and fast in response to these pollutions. This study used particulate matters and suspending particles as air pollution variables. The data of these two variables was generated by GIS arcview software.
The findings of this study are as what follow. (1) In Taipei, the air quality as indicated by particulate matters and suspending particles was cleaner in 2004 than in 1994. Air quality is getting apparent improvement in 2004. Density of air pollution in Taipei is lower than the pollution standard, which was announced by the government. (2) By R2 or adjusted R2 to compare regressions’ explain ability and by the directions and magnitudes of coefficients. This study found that a semi-log model in 1994 and a double-log model in 2004 are the best models. (3) Suspending particles have two-years time lag for effective influence on price of houses. (4) In Taipei, suspend particles had significant negative influences on prices of houses in 1994. The particulate matters had insignificant negative influences on prices of houses in 1994. (5) In Taipei, the particulate matters and suspend particles had insignificant negative influence on prices of houses in 2004. (6) If density of suspends particles reduces one unit (μg/m3), people were willing to pay 27,132 NT dollars in 1994. (7) In 2004, to reduce one unit (μg/m3) of the density of particulate matters and suspend particles, people were willing to pay 90,765 and 26,334 NT dollars respectively. After converting to price of 1994, the willingness to pay becomes 77,958 and 22,617 NT dollars respectively. (8) Though air quality has been obviously improved in 2004, people demand much more improvement. This is evidenced from the estimation results of the hedonic function of particulate matters. Its impacts on house prices were not statistically significant in 1994. Through ten years, the negative impacts turned to be extremely significant in 2004. It is obvious that people's requisition for higher air quality is stricter and stricter. (9) Even though, over the past ten years, the pollution of suspend particles had already been obviously improved, people’s willingness to pay for higher air quality is much higher (27,132 NT dollars in 1994, 26,334 NT dollars in 2004). It is obvious that people's requisition for higher air quality is stricter and stricter. (10) Suppose that no air quality improvement had been made from 1994 to 2004 and suppose that, in 2004, air quality was improved all at once, from1994 level to its 2004 level. People were willing to pay 8,682,154 NT dollars per household for the particulate matters and 3,560,706 NT dollars per household for suspend particles. (11) Following (10), total economic values of air quality improvement for the past ten years (1994 - 2004) can be get by multiplying household willingness to pay by total household number in Taipei in 2004. The total willingness to pay was 8,016.4 billion and 3,287.7 billion NT dollars for particulate matters and suspend particles. |
