Data from 50 surgeries where measurements were taken of aerosol concentration and particle size distribution were analyzed. Measurements were taken during laryngological, gynecological, orthopedic and plastic surgery procedures during which power saws, drills, electro scalpels, electro cauteries, and laser scalpel instruments were used. There were about 10,000 particle size distributions measured. The results indicated that the aerosol concentration in an operating room environment is the result of the synergistic interaction of at least three major factors: the aerosol source, the physical outlay of the operating room and its equipment, and the transport and diffusion of the aerosol. No one particular surgical type can be assumed to be the major producer of surgical aerosols. Laser scalpels, electro scalpels, and electro cauteries were the primary aerosol generators or aerosol concentrations which were measured outside the sterile zone. Power tools produced larger aerosolized mass loads than laser and electro scalpels. Positions of instrument tables, anesthesia carts, drapes, personnel, and overhead lamps affect operating room circulation patterns and time integrated concentration levels in all locations. Time integrated aerosol concentration levels for a particular surgical type can vary by a factor of four depending on surgical type, patient, and surgeon performing the procedure. Personnel entrance and egress from the operating room during surgery had little observable effect on the time integrated concentration levels in the operating room.