Are short‐term effects of pollution important for growth and optimal fiscal policy?

We study optimal fiscal policy in a stock‐flow model of the environment within an endogenous growth framework, where some pollutants have a lasting impact on environmental quality which is restored through abatement expenditure, while others dissipate and hence, have a short‐term effect on the environment. All pollutants, however, affect the productivity of a public good negatively. Given that short‐term pollution, although it dissipates, is irreversible in this sense, a government cannot ignore its negative effects since this type of pollution lowers the productivity of all inputs. We find that a larger negative effect of short‐term pollutants as well as a higher congestion effect of private capital leads to corrective fiscal policies with higher optimal income tax and abatement expenditure rates, which have favorable growth consequences. Interestingly, we find that the rate of short‐term pollution does not affect optimal fiscal policy while that of the long‐term pollution does.