關稅制度與環境品質

Tariff Schemes And Environmental Quality

本文旨在比較不同關稅制度下（以差異性關稅與單一關稅為討論範圍）本國課徵的進口關稅如何影響國外廠商的污染技術（防污比例），進而影響本國的環境品質及社會福利。得到的結果如下：若二階條件均符合，則差異性關稅下的污染比例小於單一關稅下的污染比例；若只有單一關稅下的第二階條件滿足，則差異性關稅下的污染比例大於單一關稅下的污染比例；若兩制度的二階條件均不成立，那麼兩制度下的污染比例均等於原始污染比例。至於社會福利的比較，當本國市場規模大時，兩制度的福利關係與污染比例關係相反（即污染比例越小，社會福利越大）；若本國市場甚小，則兩制度的福利關係無法確定。本文提供了一個立論基礎，說明從差異性關稅制度轉換為單一關稅制度，不必然造成防污技術下降（污染比例提高）、社會福利惡化的結果，而須視防污成本函數、環境損害函數及市場規模而定。 This paper examines the effects of tariffs on the pollution abatement technology of the foreign firms and in tum on the domestic environmental quality and welfare. The schemes of discriminatory tariff and uniform tariff are compared. The following result is obtained. A shift from the scheme of discriminatory tariff to that of uniform tariff does not necessarily raise the pollution of unit output and reduce the social welfare of home country. The outcome depends on the abatment cost function, environment damage function and market size.

This paper examines the effects of tariffs on the pollution abatement technology of the foreign firms and in tum on the domestic environmental quality and welfare. The schemes of discriminatory tariff and uniform tariff are compared. The following result is obtained. A shift from the scheme of discriminatory tariff to that of uniform tariff does not necessarily raise the pollution of unit output and reduce the social welfare of home country. The outcome depends on the abatment cost function, environment damage function and market size.