由於環境品質改變之成本或效益沒有一個直接的市場可以衡量，為了 克服此一問題，Rosen 於1974年提出特徵價格法完整的理論架構。其利用 差異性財貨之價值受其所具有之不同屬性數量影響，於是可用計量方法將 個別屬性之價值導引出來。本文即是利用Rosen 所提之二階段過程，分別 估計台北、台中、高雄三地區之特徵價格函數，然後利用第一階段所獲得 之價格資料進行第二階段逆需求函數的估計。本研究除了進行上述二階段 之估計，另外以高雄地區為例，計算該地區因水泥廠存在，PM10濃度增加 對當地房地產價格之影響，此一影響也就是水泥廠存在PM10濃度增加所造 成的社會外部成本。 / The measurement of the benefit of environmental improve-ments is difficult because typically there are no markets for environmental guality. However, one can observe behavior in markets that are related to environmental guality , and it is sometimes possible to measure people’s willingness to pay for the environmental goods by using data from these markets. Hedonic methods is one of several techniques for doing this. Hedonic methods are based on the realization that some goods or factors of production are not homogeneous and can differ in numerous characteristics. My study follows the theoretical model that provided by Sherwin Rosen in 1974.According to Rosen’s model, estimation requires a two-step procedure. First, estimate the hedonic price function. Second, estimate the demand function for air guality(PM10’s density). At last , I try to estimate how much the cement plant decreases houses price. In fact , the estima-tion is equal to measure the external cost caused by the ce-ment plant around Kaushang area.