Are you asking where you enter this information into LEAP? To do this, check the box next to "Environmental Externality Costs", under the Costs tab of Basic Params. You will then be able to add pollutants under the Effects branch (this will appear in your tree underneath Key Assumptions) and assign them externality costs.

Best,

Taylor

There is no single "accepted value" for the externality cost of various pollutants. The determination of these externality costs is highly contentious, depends on many factors, and would require a review of current literature in order to understand the issues and to assign a reasonable value. I'm afraid I'm not familiar enough myself with this literature for NOx and SO2 to be able to recommend a good source.

Since you are unsure which values to use, is it imperative that they be included in your analysis?

Taylor