Each spray will create a micro-needle nano layer along with Quaternary Ammonium Compound (QAC) layer last up to 28 days. This layer will protect the surface from dirt and contaminant. The micro-needle will repel dirt, while any contaminant that falls on the surface, the protein layer will be denatured then making  the germs vulnerable and effectively inactivate the contaminant. 

Without the protecting layer, the surface will not repel dirt and contaminant can multiply on the surface then making it a risk of spreading more germs to surrounding.