| Abbreviation | Definition |
|---|---|
| PEM | Palustrine Emergent Wetlands |
| PEM | Persistent EMergent |
| PEM | Personal Environmental Monitor |
| PEM | Project Establishment and Management |
| PEM1 | Persistent EMergent type 1 |
| PEM2 | Persistent EMergent type 2 |
| PEMP | Project Environmental Management Plan |
| PEMP | Project Environmental Monitoring Programme |
| PEMS | Predictive Emissions Modeling System |
| PEMS | Protected Environment Management System |
| PEMU | Panel-mount Environmental Monitoring Unit |
| PEMU | Provincial Environmental Management Unit |
| PEMX | Palustrine Emergent Wetlands / eXcavated |
| PEON | Polar Environmental Officers Network |
| PEP | Partners for Environmental Progress |
| PEPA | Purchase Environmental Protective Association |
| PEPG | Plant Environmental Physiology Group |
| PEPS | Productivity Environmental Preference Survey |
| PEQ | Partners for Environmental Quality |
| PEQ | Planners for Environmental Quality |