Click for more information on Public Health Service Decorations: PHS Commissioned Corps Awards CCPM Pamphlet 

If Air Force members wear more than one United States Nonmilitary Decorations, arrange in order of acceptance. If member wears two or more from the same agency, that specific agency decides the precedence.  Do not wear these decorations unless Airmen wear US military decorations and service medals. Ribbons must be the same size as Air Force ribbons. Wear only those decoration and ribbons awarded by federal agencies and earned while in military service. (AFI 36-2903 paragraph 11.5.44.)

Distinguished Service Medal

This is the highest PHS Commissioned Corps award. Criteria includes outstanding contributions to the mission of the PHS. Such achievement may range from the management of a major health program, to an initiative resulting in a major impact on the heath of the Nation. Can also be conferred for a one-time heroic act resulting in great savings to life, health, or property. 

Meritorious Service Medal

The MSM is presented in recognition of meritorious service of a single, particularly important achievement, a career notable for accomplishments in technical or professional fields, or unusually high-quality and initiative in leadership. The level of accomplishment meriting this award may include: a highly significant achievement in research program direction or program administration; a series of significant contributions; a continuing period of meritorious service; or exhibition of great courage in hazardous work in an emergency. 

Commendation Medal

The CM is presented for a level of proficiency and dedication distinctly greater than that expected of the average officer. The CM recognizes: sustained high-quality work achievement in scientific, administrative, or other professional fields; application of unique skill or creative imagination to the approach or solution of problems; or noteworthy technical and professional contributions that are significant to a limited area.