What was found
SHORTLY AFTER TAKEOFF, PAXS & FLIGHT ATTENDANTS IN BUSINESS & FIRST CLASS NOTICED AN ODD SMELL. FLIGHT ATTENDANTS BECAME LIGHT HEADED & DIZZY. FUMES REMOVAL CHECKLIST ACCOMPLISHED, SYS LOOKED NORMAL. THE DECISION WAS MADE TO RETURN. A MEDICAL EMER WAS DECLARED & THE FLIGHT LANDED WITHOUT FURTHER INCIDENT. ACCOMPLISHED CABIN AIR QUALITY INSPECTION IAW MCM 05-96-70 & FIM 21-00-00-810-808. NO DISCREPANCIES FOUND, NO SOURCE FOUND BY LOCAL AUTHORITIES. RECIRCULATION AIR FILTERS WERE REPLACED AS A PRECAUTION. THE ACFT WAS GNDED.