Seeking raw spatial data for custom surrogates

I am making 1.3km resolution spatial surrogates using ArcGIS tools (not the Spatial Allocator). I’ve been trying to track down the raw data that the EPA 4, 12, and 36 km data are based on, so that my 1.3km surrogates are consistent with these other sets. Where I can find these data?

All shapefiles used for EPA’s surrogates have been posted here.

Which platform are you working on the surrogates for? 2014? 2016? Other?