Isn’t this too big? We use COI for the valuation, in which values inputted are that of the Philippine setting.
An economic valuation exceeding one billion local currency units is not necessarily unreasonable. For example, the benefits of the U.S. Clean Air Act were estimated to be billions of U.S. Dollars. The valuation estimate depends on all of the preceding data choices you made: the magnitude of air quality change, population, incidence rates, epidemiological literature, and valuation function.
Before applying a COI estimate to your health impacts, ensure that your health impact estimation is reasonable. Consult with fellow researchers, test your data inputs, and conduct sensitivity analyses. Finally, consider the quality and applicability of the COI estimate to your study. You may want to consider (among other criteria), whether the COI estimate is (a) from peer-reviewed literature, (b) from the country/area you are analyzing, and © directly applicable to the health endpoint in your analysis.