In a polluting Cournot duopoly with homogeneous goods, this work compares the environmental, public finance and welfare impacts of three policies: an emissions tax, an abatement subsidy, and a policy mix. A subsidy, alone or coupled with a tax, always increases abatement; however, taxation disincentivises production, leading to decreased environmental damage, which positively affects welfare. Except for a rather inefficient technology, the emissions tax produces the lowest environmental damage; this positive effect, jointly with the tax revenues the government collects, more than offsets the negative impact on profits and consumer surplus due to output contraction, leading to the highest welfare. Only when societal awareness is negligible and technology is inefficient does the government design a policy providing a subsidy.

在具有同质商品的污染古诺双寡头垄断中，这项工作比较了三种政策对环境、公共财政和福利的影响：排放税、减排补贴和政策组合。单独的补贴或与税收相结合的补贴总是会增加减排量；然而，税收会抑制生产，从而减少环境破坏，从而对福利产生积极影响。除了技术效率相当低之外，排放税对环境的损害是最小的；这种积极效应，加上政府征收的税收，足以抵消产出收缩对利润和消费者剩余的负面影响，从而带来最高的福利。只有当社会意识微不足道且技术效率低下时，政府才会制定提供补贴的政策。