Update description

This update includes all submissions until 10 April 2014 from the 2014 Emission Reporting Round for the year 2012
--> Main pollutants were gridded for the year 2012 with the latest available submissions
--> HMs (Cd, Hg, Pb) and POPs (PCDD/PCDF, HCB, B[a]P) were gridded for 2012 on national total level