emissions air injection removed?

i have a 2000 chevy s-10 2.2L with 140 k! i will try and make this quick and painless. I was in a car wreck. hit the front of the vehicle. i went to macco to save money. i cost me a lot more. when they finnally handed me my truck i noticed a noise comming from the headers and i know this because i hear it and i smell carbon dioxide, or exhaust coming right by the headers.

my question is they hooked the air injection pump? wrong and know i wanna know what it's its purpose and if i could run without it? people have told me is just for emissions purpose and that i wont pass the test without it, so i need to know about it.

thanks in advance :D