Abstract: This paper develops a Cournot competition model that incorporates emission reduction costs to compare the effects of emission tax and emission standard policies from the perspective of government. Considering the differences in emission reduction cost coefficients between two firms and the emission reduction targets set by the government, it analyzes the resulting impacts on producer surplus, consumer surplus and total emissions under each policy. The findings reveal that under an emission standard policy, regardless of the difference in emission reduction cost, higher emission standard set by the government lead to decreased emissions from both firms. In contrast, under the emission tax policy, a higher tax rate leads to lower total emissions only when the cost disparity between the two firms is relatively small. A higher tax rate set by the government is able to decrease the total emissions of the two firms. Additionally, both policies are found to disadvantage firms with higher emission reduction costs. The analysis of economic benefit and consumer surplus indicates that emission standard policy is more effective than the emission tax policy. This paper provides practical policy recommendations for governments aiming to regulate carbon emissions in different market environments.

Key words: emission tax, emission standard, emission reduction costs, Cournot competition

摘要： 通过构建纳入企业减排成本的古诺竞争模型，从政府的角度对比排放税和排放标准政策的效果。基于两家企业的减排成本系数差异及政府减排比例设定，系统分析两种政策下的生产者剩余、消费者剩余和排放水平差异。研究结果表明：在排放标准政策下，无论企业减排成本差异如何，政府设定的排放标准越严格，企业总排放量越低；而在排放税政策下，仅当两企业减排成本系数差异较小时，提高税率可有效降低两企业排放总量；同时发现，排放税政策和排放标准政策均不利于减排成本系数大的企业。通过对比经济效益和消费者剩余发现，排放标准政策整体优于排放税政策。本研究为政府在不同市场环境下如何控制碳排放提供了管理建议。

关键词: 排放税, 排放标准, 减排成本, 古诺竞争