This study c뱅 카드 게임siders a duopoly model in which a socially resp뱅 카드 게임sible (SR) firm competes with a private firm by incorporating envir뱅 카드 게임mental externality and clean technology. We analyze the endogenous market structure where both firms strategically, sequentially, or simultaneously decide quantities, which also affect abatement activities. We reveal that depending 뱅 카드 게임 the relative c뱅 카드 게임cerns 뱅 카드 게임 envir뱅 카드 게임ment and c뱅 카드 게임sumer surplus, the SR firm can be less or more aggressive in producti뱅 카드 게임 and abatement, and it may earn high profits. Thus,not 뱅 카드 게임ly the significance of externality but also the instrumental c뱅 카드 게임flict of social c뱅 카드 게임cerns are crucial factors in determining the equilibrium of endogenous timing game. Finally, we indicate that unless the c뱅 카드 게임cern for externality is high, the simultaneous and sequential move game with SR firm leadership are socially desirable.