What was found
DURING DEPARTURE, THE PILOT & MEDICAL CREW SMELLED A BURNING ODOR IN THE CABIN. THIS WAS MOST LIKELY CAUSED BY THE VERY HEAVY POLLEN SEASON. THE POLLEN IS CIRCULATED BY THE DOWNWASH, GETS ON THE HOT ACFT ENG SURFACES WITH A RESULTING BURNED SMELL. HOWEVER THE ODOR LINGERED AS WE CLIMBED OUT & THE SMELL WAS NOT GOING AWAY. ABORTED THE FLIGHT & RETURNED TO BASE WITHOUT FURTHER ISSUES. ACFT WAS TAKEN OUT OF SERVICE. FOUND NO EVIDENCE OF FIRE, GND RUN & FLIGHT CHECK WAS PERFORMED, NO FURTHER SMELLS. TRANS DECK & ENG DECK FOR ANY DEFECTS, NONE FOUND. PERFORMED GND RUN TO VERIFY ISSUE WITH, NO DEFECTS NOTED. AN OPERATIONAL CHECK FLIGHT WAS PERFORMED TO CONFIRM WITH NO ADDITIONAL DEFECTS NOTED. THIS ACFT WAS PLACED BACK INTO SERVICE AT THIS TIME.