| ATS: | Allowance Tracking System |
| ATUs: | Allowance Transfer Units |
| BTUs: | British Thermal Units |
| CAA: | Clean Air Act |
| CDM: | Clean Development Mechanism |
| CEMs: | Continuous Emissions Monitoring Systems |
| CERs: | Certified Emissions Reductions |
| CFCs: | Chlorofluorocarbons |
| CO: | Carbon Monoxide |
| CO2: | Carbon Dioxide |
| DERs: | Discrete Emissions Reductions |
| EGUs: | Electric Generating Units |
| EPA: | Environmental Protection Agency |
| ERCs: | Emissions Reduction Credits |
| GHG: | Greenhouse Gases |
| HAPs: | Hazardous Air Pollutants |
| HCFCs: | Hydochlorofluorocarbons |
| JI: | Joint Implementation |
| KW: | Kilowatt |
| MACT: | Maximum Achievable Control Technology |
| MMBTU: | Million btu=s |
| MW: | Megawatt |
| NAAQS: | National Ambient Air Quality Standards |
| NESHAP: | National Emission Standards for Hazardous Air Pollutants |
| NOx: | Nitrogen Oxides |
| NSR: | New Source Review |
| ODS: | Ozone Depleting Substances |
| OTAG: | Ozone Transport Assessment Group |
| OTR: | Ozone Transport Commission |
| PM: | Particulate Matter |
| RECLAIM: | Regional Clean Air Incentives Market |
| RFS: | Renewable Fuels Standard |
| RPS: | Renewable Portfolio Standard |
| RTCs: | RECLAIM trading credits |
| SCR: | Selective Catalytic Reduction |
| SIPs: | State Implementation Plans |
| SO2: | Sulfur Dioxide |
| UNFCCC: | United Nations Framework Convention on Climate Change |
| VOCs: | Volatile Organic Compounds |
