AST_05 Surface Emissivity data is already atmospherically corrected.
https://asterweb.jpl.nasa.gov/content/03_data/01_Data_Products/release_surface_emissivity_product.htm?fireglass_rsn=true#fireglass_params&tabid=abb448dee4e50069&start_with_session_counter=3&application_server_address=l3harris-e8.prod.fire.glass

Thanks for your concern.