A 2" abs vent pipe is hardwired in a concrete slab. It was supposed to be set in a upward slope before it goes out and up. The slope ended up being at a slight downward direction before it goes out and up. Given the ever so slight downward direction some of the bad gasses would still escape just fine in the upward direction. Only it would not be a full-on 2" vent in an upward direction. What are the implications? I mean how bad is this and how bad a problem can this cause? By the way, before you answer that this is not code, the place is an illegal stand alone bathroom on a ranch. I don't care about passing some inspection. I care about bad gasses in the bathroom.