本文建立一個產品垂直差異化雙占模型，市場上有兩家廠商，一原始產品可回收較高，另一原始產品可回收率較低，並在市場上進行價格競爭。探討當廠商受到EPR規範時，會如何在最適產品可回收率與最適減污研發量之間做取捨，並且探究何種因素會影響廠商的決策。最後在進一步探討廠商進行減污研發ER&D是否是有助於社會福利的提升。 本文發現， 當消費者普遍重視產品可回收率或者產品邊際汙染量增加時，會使兩家廠商均減少減汙研發量。並且發現當廠商進行減汙研發ER&D且政府收取較高的廢棄物處理費時，會使兩廠商生產的產品總汙染高於廠商未進行減汙研發ER&D時的產品總汙染；政府收取較低的廢棄物處理費時，會使兩廠商生產的產品總汙染低於廠商未進行減汙研發ER&D時的產品總汙染。最後，發現當廠商進行減汙研發ER&D，確實可使整體社會福利提升。 另外，本文也發現，當政府收取較高廢棄物處理費時，無論有無進行減污研發ER&D的最適產品可回收率均會低於社會最適的產品可回收率，且低產品可回收率的廠商所投入的減污研發量會高於社會最適；當政府收取較低廢棄物處理費時，無論有無進行減污研發ER&D的最適產品可回收率均會接近或者超過社會最適的產品可回收率，且原本低產品可回收率的廠商所投入的減污研發量會少於社會最適。並且在消費者普遍重視產品可回收率的情況下，原本高產品可回收率廠商所投入的減污研發量與社會最適之間的關係必須依消費者重視程度而定，但在消費者普遍不重視產品可回收率的情況下，原本高產品可回收率廠商所投入的減污研發量會高於社會最適。 ;This thesis is to examine how the environment policy affects a duopoly model with vertical product differentiation. There are two producers in the market of a recyclable product in competition. One has a higher recycle rate than the other. The aim is to study how and on what key issues the producers choose between the optimal recycle rate and the optimal pollution reducing R&D, when the extended producer responsibility (EPR) is implemented. The question of whether and how the environmental research and development (ER&D) of the producers improving social welfare is discussed. It is discovered in this thesis that the producers will put less efforts on pollution reducing R&D when the consumers pay more attention on the recycle rate or on the marginal pollution rate of the product. Under a higher disposal cost charged by the government, the total volume of pollution due to the two producers is lager when they invest in ER&D. But under a lower disposal cost, doing ER&D will bring the total pollution to a smaller volume. On the other hand, it is also observed in this thesis that a higher disposal cost will make the optimal recycling rate of the product less than the social optimum, regardless ER&D being involved or not. In this case, the producer with lower recycle rate puts more efforts on ER&D than that the social optimum demands. In another situation while the government charges a lower waste processing fee, the optimal recycling rates from both producers are close to or exceed the social optimum, also regardless of ER&D. It also happens that the producer with lower recycling rate puts less efforts on ER&D than that the social optimum demands. The amount of investment on ER&D of the producer with high recycling rate depends on how the consumers look at the recycling rate. If the general consumers emphasize on the recycling rate, that producer will put corresponding efforts on ER&D to respond to the social optimum. But if the general consumers do not emphasize on recycling rate, the producer with a higher recycling rate will put more efforts on the pollution reducing R&D more than that the optimum demands.
