PEM may stand for:

• Peabody Essex Museum
• Photoelastic modulator
• Polyelectrolyte multilayer
• Porous European Mix – a type of asphalt used on roads and airport runways, commonly referred to as PEM
• Portable Emissions Measurement System (PEMS)
• Positron Emission Mammography
• Prescription-event monitoring (Pharmaceuticals)
• Privacy-enhanced Electronic Mail
  • the .pem filename extension is used for a Base64-encoded X.509 certificate
• Protein-energy malnutrition
• Proton exchange membrane – as in "fuel cell", applications include use in proton-exchange fuel cells, used to manipulate hydrogen for energy conversion
• The IATA code for the Padre Aldamiz International Airport in Puerto Maldonado, Madre de Dios, Peru
• Pemberton railway station, England; National Rail station code PEM
• Plesk Enterprise Manager - former name for Parallels Operation Automation by Parallels, Inc.

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