As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PHL - FLT 1737 EN ROUTE RDU TO PHL. THE CREW NOTICED A SLIGHT ODOR AT 15,000 FT DURING CLIMB. AFTER LEVEL OFF, THE ODOR BECAME SLIGHTLY MORE NOTICEABLE. AS THE DESCENT STARTED, AN ELECTRICAL SMOKE ODOR BECAME APPARENT. THE FLIGHT CREW DECLARED AN EMERGENCY TO RECEIVE EXPEDITED HANDLING INTO PHL. THE FLIGHT LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE REPLACED THE LEFT SIDE RECIRCULATION FAN. OPERATIONALLY CHECKS OK.