What is the function of this button

Passo

muno1 (muno1) 2019-10-07 18:46:54 +0500 #1

omersiddiqui5482 (omersiddiqui5482) 2019-10-08 09:44:16 +0500 #2

i cant see what is the symbol can you please take a closeup!

amir_ghafoor (amir_ghafoor) 2019-10-20 15:33:44 +0500 #3

Its an ionizer. Kinda helps you breath bacteria free air