What makes farts so smelly & noisy?

Part of 

U.S. Border Wall 

Falls Over 

Into Mexico

 anagrams to

 Fart Excretion. Oops. Full Drawers. 

  I'm Ova, Blob.

https://cnalifestyle.channelnewsasia.com/wellness/why-do-we-fart-smells-flatulence-12082484

The spread of a fart’s odour can be tremendous as a fart can be expelled as fast as the speed of sound.