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