Ill. Admin. Code tit. 35, § 201.103
a) The following abbreviations have been used in this Part:
| Act | Illinois Environmental Protection Act |
| AER | Annual Emissions Report |
| Agency | Illinois Environmental Protection Agency |
| btu or Btu | British thermal units |
| CAA | Clean Air Act |
| CAAPP | Clean Air Act Permit Program |
| CO | Carbon monoxide |
| CO2e | Carbon dioxide equivalent |
| gal | gallons |
| HAPs | hazardous air pollutants |
| hp | horsepower |
| hr | hour |
| gal/mo | gallons per month |
| gal/yr | gallons per year |
| kPa | kilopascals |
| kPa absolute | kilopascals absolute |
| kW | kilowatts |
| l | liters |
| Mg | megagrams |
| m3 | cubic meters |
| MM | million |
| MW | megawatts; one million watts |
| NESHAP | National Emission Standards for Hazardous Air Pollutants |
| NMOC | nonmethane organic compounds |
| NOx | nitrogen oxide |
| NSPS | New Source Performance Standards |
| NSR | New Source Review |
| PBR | permit by rule |
| PM | particulate matter |
| PM10 | particulate matter with an aerodynamic diameter less than or equal to 10 micrometers |
| PM2.5 | particulate matter with an aerodynamic diameter less than or equal to 2.5 micrometers |
| PSD | Prevention of Significant Deterioration |
| psi | pounds per square inch |
| psia | pounds per square inch absolute |
| ROSS | Registration of Smaller Sources |
| SO2 | sulfur dioxide |
| TPY | tons per year |
| USEPA | United States Environmental Protection Agency |
| VOM | volatile organic material |
| yr | year |
b) The following conversion factors have been used in this Part:
| English | Metric |
| 1 gal | 3.785 1 |
| 1,000 gal | 3.785 m3 |
| 1 hp | 0.7452 kW |
| 1MMBtu/hr | 0.293 MW |
| 1 psi | 6.897 kPa |
(Source: Amended at 41 Ill. Reg. 4140, effective March 24, 2017)