We are interested in the assumptions that EPA made about age distribution of vehicles in the 2014 NEI MOVES on-road emissions and the corresponding emission factor tables used for SMOKE-MOVES. The 2014 NEI v2 documentation (section 6.2.1) notes that EPA purchased data from IHS Markit, which was used to develop the inputs for MOVES. Is there a summary of the IHS dataset available so that we could look at age distribution? Also, related, is there a list of the default reference counties that would be used in SMOKE-MOVES?
There is information about the dataset here:
The county age fraction data for all counties is in the CountyAgeFraction files in this directory: