Remove ' ' from blank cells while export GridView to Excel using OpenXml in ASP.Net

I followed the excellent guide HERE, written by Mudassar Khan. My only problem is my database contains empty cells that are populated with "&nbsp" in the exported excel file. 

could someone help me out by modifying the above linked code to add the functionality of getting rid of &nbsp and replacing it with just blank cells. 

I would be eternally greatful.