在污染產業中，相對於數量競爭而言，文獻上價格競爭導致較高的市場總 產出與社會福利的結論將不必然成立。本文檢視污染產業中， 數量與價格競爭 環境對於廠商策略性履行環境企業社會責任的誘因與經濟福利的影響。研究結 果指出，相對於價格競爭模式下的市場均衡，廠商在數量競爭模式下產量較 低，價格較高，減污投入較多，污染排放較少。換言之，在價格競爭模式下， 較高的產量雖然提升了消費者剩餘，較少的減污投入卻增加了環境污染損害。 因此，權衡消費者剩餘與環境污染損害對於社會福利消長的影響， 我們發現當 污染造成的邊際損害過大的情況下，數量競爭模式下的社會福利將會高於價格 競爭模式下的社會福利。

The well-known result that price rather than quantity competition delivers a higher amount of output and consequently higher social welfare may not hold in a polluting industry. This paper examines firms’ incentives for undertaking strategic ECSR activities under quantity and price competition, respectively. Compared to the equilibrium outcome under price competition, we find that the firms produce fewer outputs, charge higher prices, invest more in ECSR activities, and discharge less emission under quantity competition. In other words, while a higher output level increases consumer surplus, a lower level of ECSR investment intensifies environmental damage. Due to the trade-off between consumer surplus and environmental damage, social welfare is higher under quantity competition if the marginal environmental damage is too large.