DO328 CREW HAS SMOKE; FOG IN THE CABIN ON DSCNT INTO BNA.

Narrative

IN DSCNT AND LEVELING OFF AT FL200; THE FO SAID HE SMELT SMOKE. I (CAPT) DID NOT SMELL SMOKE; BUT OBSERVED A LIGHT HAZE/FOG IN THE COCKPIT. WE CALLED THE FLT ATTENDANT AND SHE RPTED A FOG IN THE FORWARD CABIN. BOTH PLTS DONNED OXYGEN MASKS; DECLARED AN EMER WITH ZID AND INITIATED EMER PROCS PER COMPANY REQUIREMENTS. ALL EMER CHKLISTS (APPLICABLE CHKLISTS) WERE COMPLETED PRIOR TO LEVEL OFF AT 10000 FT MSL. AT 10000 FT THE HAZE/FOG DID NOT INCREASE OR APPEAR TO DECREASE. WE NOTIFIED CTR THAT THE PROB WAS STABLE AND DID NOT FORESEE A PROB CONTINUING TO BNA. WE CONTINUED TO DESCEND TO 4000 FT AND REMAINED ON OXYGEN FOR THE DURATION OF THE FLT. WE ARRIVED AT BNA APROX 15 TO 18 MIN AFTER DECLARING THE EMER. CFR MET US AT THE TXWY AND OBSERVED NO SMOKE OR FIRE. WE TAXIED TO THE GATE AND DEPLANED NORMALLY. I BELIEVE THE HAZE WAS CAUSED BY CONDENSATION FROM THE ACFT PACKS. AT NO TIME DID THE HAZE/FOG SMELL OF AN ELECTRIC OR OIL SOURCE. I BELIEVE THE HAZE/FOG DISSIPATED DUE TO TEMPERATURE CHANGE. THE DECISION TO CONTINUE TO BNA WAS A CREW DECISION. THERE WERE NUMEROUS ARPTS ENRTE TO BNA; BUT; GIVEN THAT THE SOURCE OF HAZE/FOG WAS NOT ELECTRIC OR OIL IN NATURE; WE DECIDED TO CONTINUE. WE HAD CFR AVAILABLE; IF NEEDED; HAD THE SIT WORSENED. IF THE SOURCE WAS ELECTRIC/OIL WE COULD HAVE LANDED A FEW MINS EARLIER. AFTER LNDG; THE ACFT WAS INSPECTED AND MX COULD NOT DUPLICATE PROB.