Pollution Tax and Social Welfare in an Oligopoly: Asymmetric Taxation of Homogeneous Polluters

寡占市場結構下的汙染稅與社會福利：對同質汚染製造者課徴不對稱稅

本間聰(Satoshi Honma)

《農業與資源經濟》 6卷1期 (2009/06) Pp. 47-68

https://doi.org/10.29796/ARE.200906.0003

摘要

本研究在寡占市場結構，污染製造者爲同質且進行數量競爭的情況下，不對稱污染稅對污染製造者的影響。之前的文獻假設污染製造者爲同質且面對對稱的汙染稅。之前的文獻發現，在同質寡占的市場結構下，單一污染稅率是次佳選擇(the second best)。然而，對於同質污染製造者課徵不對稱的汙染稅率會產生總成本節省的效果(an aggregate cost-saving effect)。我們在單一污染稅率且污染排放量不變下考慮單一污染稅率向量(the uniform tax vector)。我們推導出對於同質的污製造者使用不對稱稅率將導致社會福利提升的條件。此外我們也證明了當上述條件成立時，訂定不對稱的排放標準也會提高社會福利。

關鍵字

Cournot雙占 ； 廠商不對稱 ； 污染稅 ； 環境政策 ； 效率與平等

並列摘要

This paper studies the effects of unequal pollution taxation on identically polluting oligopolists engaged in Cournot competition. Previous studies have assumed a symmetric treatment of homogeneous firms, and the uniform tax is regarded as the second best in that context. However, the unequal treatment of homogeneous firms generates an aggregate cost-saving effect specific to oligopolies. This paper considers a manipulation of the uniform tax vector without changing the total emissions under the uniform pollution tax. A sufficient condition is derived to guarantee that the unequal taxation of ex ante homogeneous polluters increases social welfare. We show that if the sufficient condition is satisfied, unequal emissions standards also increase social welfare.

並列關鍵字

Cournot Duopoly ； Firm Asymmetry ； Pollution Tax ； Environmental Policy ； Efficiency and Equity