MD88 CREW HAD SMOKE AND FUMES IN THE CABIN AND LOST CTL OF CABIN PRESSURIZATION.

Narrative

CREW PERFORMED NORMAL FIRST FLT OF THE DAY PREFLT. THE ACFT HAD BEEN DEICED PRIOR TO OUR ARR. THE LOG SHOWED THAT THE ACFT HAD BEEN IN ZZZ FOR 2 DAYS FOR MAINT ON THE L AIR CONDITIONING PACK. AFTER TKOF; WE HAD A L AIR CONDITIONING HIGH TEMP MESSAGE. THE CAPT FLEW THE ACFT AS I READ AND PERFORMED THE PROC. DURING CLBOUT; A FLT ATTENDANT CALLED AND SAID THAT THERE WAS AN ODOR IN THE CABIN. IN THE COCKPIT WE SMELLED THE NORMAL ODOR OF DEICING FLUID. A FEW MINS LATER; A FLT ATTENDANT CALLED TO SAY THAT THE ODOR WAS GETTING SOMEWHAT WORSE. WE DECIDED TO RETURN TO ZZZ AND I FLEW THE PLANE WHILE THE CAPT TALKED TO DISPATCH AND MAINT. OUR ALT WAS NEAR FL250. DURING THE DSCNT THE FLOW LIGHT ILLUMINATED ON THE OVERHEAD PRESSURIZATION PANEL. I INCREASED PWR ON THE R ENG; THE LIGHT STAYED ILLUMINATED. A FLT ATTENDANT CALLED TO SAY THAT THE ODOR AND HAZE WERE NOW MUCH WORSE. THE CAPT TURNED OFF THE L PACK. ABOUT THE SAME TIME THE CABIN ALT LIGHT ILLUMINATED. THE CAPT TOOK CTL OF THE ACFT. WE PUT ON OUR OXYGEN MASKS; DECLARED AN EMER; AND STARTED A RAPID DSCNT INTO ZZZ1. THE PAX OXYGEN MASK DEPLOYED AUTOMATICALLY. I PERFORMED THE SMOKE REMOVAL CHKLIST AND COORDINATED WITH THE FLT ATTENDANTS; WHILE THE CAPT FLEW THE ACFT AND TALKED TO ATC. WE ACCOMPLISHED THE DSCNT; APCH; AND BEFORE LNDG CHKLIST AND LANDED AT ZZZ1. WE STOPPED THE ACFT ON THE RWY AND ASKED FIRE RESCUE TO INSPECT FOR ANY SIGNS OF FIRE OR SMOKE. I OPENED THE COCKPIT DOOR TO INSPECT THE SIT IN THE CABIN AND TALKED TO THE LEAD FLT ATTENDANT AND THEN TO THE CAPT. WE AGREED THAT AN EVAC WOULD NOT BE NECESSARY. THE PAX WERE LATER DEPLANED DOWN THE AFT STAIRWAY TO BUSSES TO THE TERMINAL.