| Abbreviation | Definition |
|---|---|
| NFAP | National Forestry Action Programme |
| NFEC | North Fork Environmental Council |
| NFS | National Forest Service |
| NG | Natural Gas |
| NGGT | Next Generation Gas Turbine |
| NGS | Niedersächsische Gesellschaft zur Endablagerung von Sonderabfall mbH |
| NGS | Niedersächsische Gesellschaft zur Endablagerung von Sonderabfall mbH |
| NHA | National Heritage Area |
| NHCP | Natural Heritage Conservation Program |
| NHDA | National Hydrocarbons Data Archive |
| NHE | Natural Heritage Evaluation |
| NIEA | Northern Ireland Environment Agency |
| NIEHS | National Institute Of Environmental Health Science |
| NIEHS | The National Institute Of Environmental Health Sciences |
| NIER | National Institute of Environmental Research |
| NIES | Nanjing Institute of Environmental Sciences |
| NIES | National Institute For Environmental Studies |
| NIOSH | The National Institute for Occupational Safety and Health |
| NIPR | New Ideas For Pollution Regulation |
| NISER | Nepal Institute for Social and Environmental Research |