| 摘要: | 許多產業的生產活動通常都會產生汙染，造成環境外部性的問題。政府通常會針對這些汙染訂定環境政策來將外部成本內部化，使追求利潤極大的廠商考慮減產或投入汙染防治以減少環境損害。一般而言，不同的廠商在技術上也會有所差異，使授權行為可能發生。因此，當廠商投入汙染防治時，廠商間也很有可能存在汙染防治技術差異，使汙染防治技術授權發生於不同技術的廠商之間。另外，汙染稅為解決外部性最簡單有效的方法，但是傳統汙染稅的制定，並無考慮稅額的設定是否會影響廠商間汙染防治的授權行為，因此本文欲探討具汙染防治技術差異的廠商，在面對汙染稅下可能的授權行為，以及政府的最適政策。
為此，本文假設在製造汙染的寡占產業中有兩家生產同質產品的廠商，兩廠商生產商品造成的單位環境損害不同且無生產成本，來建構多階段賽局。此外，考量到現實環境政府在政策的制定並不會時常變動，我們將分別討論汙染稅在長期與短期下對廠商間汙染防治授權行為的影響，並以固定授權金制度進行分析。結果發現，當汙染稅在外生給定下，可能發生授權能有更好的社會福利，但兩廠商間卻不進行授權的狀況，使得市場失靈。若汙染稅為內生，當汙染防治技術劣勢廠商落後差距較小，政府將訂定較低的汙染稅使授權發生；當技術落後差距較大，政府將會訂定較高的汙染稅使授權不發生。因此，若能同時考慮生產帶來的環境損害以及廠商間的授權行為將可以避免市場失靈的問題。
;The production activities of many industries usually have pollution and cause environmental externality. The government usually use the environmental policy to solve this problem, so that firms may have incentive to reduce production or use abatement technology to reduce environmental damage. Generally, different firms will have different technology. Therefore, when a firm do pollution abatement technology , there is also a possibility that there will be different pollution abatement technology among firms, so that the abatement license occurs among firms with different technology. In addition, pollution tax is the simplest and most effective way to solve externality problem. However, the setting of traditional pollution tax does not consider whether the tax amount will affect the abatement license. Therefore, this study discusses government’s optimal policy and firms abatement license when they tax by government.
For that, we set the multi-stage game to study this thesis. In this game, we assume two firms produce homogeneous products with pollution, their marginal environmental damage is different, and they don’t have any production cost . In addition, considering that the government′s policy will not change frequently, we will use the fixed fee to analysis pollution taxes on the abatement license between firms in the long-term and short-term. We can find that when the pollution tax is exogenous variable, abatement license may get the better social welfare, but the abatement license is not happen between the firms, which causes market failure. If the pollution tax is endogenous variable, the government will set a lower pollution tax to allow the abatement license occur when the disadvantaged firm of pollution abatement technology gap is small. And the government will set a higher pollution tax to allow the abatement license occur when abatement technology gap is big. Therefore, if we can consider both the environmental damage caused by production and the abatement license between firms, the problem of market failure can be avoided. |
