The current article aims at studying the effects of taxation on environmental quality, in an economy where its agents are responsible. Individual responsibility towards nature is modelized by the voluntary effort to which the households have agreed insofar as the improvement of environmental quality is concerned. It is an original way to show that the individuals may feel committed towards the environment and assume obligations towards it as well as towards environmental public policy. Given that, in our model, such effort is taken from one's allocated time for leisure, its opportunity cost is that of the sacrificed time for leisure, and is therefore equal to the individual's wage. We shall highlight that State intervention through the introduction of a (green) tax always crowds out individual responsibility. However, the intensity of this crowding-out depends on the performance of the State. Moreover, State intervention could, depending on the amount of crowding-out, reduce the overall quality of the environment. In a general equilibrium setting, we show that the crowding-out effect is not systematic. This is because there will then be an interaction between effort (or work time) and the cost of that effort (linked to the individual's wage, and therefore to production and finally to work/effort). In this article, we shall discuss the conditions under which public policy crowds out individual responsibility within this context.