Emission may refer to:
Chemical products Emission of air pollutants, notably: Flue gas, gas exiting to the atmosphere via a flue Exhaust gas, flue gas generated by fuel combustion Emission of greenhouse gases, which absorb and emit radiant energy within the thermal infrared range Emission standards, limits on pollutants that can be released into the environment Emissions trading, a market-based approach to pollution control
Electromagnetic radiation Emission spectrum, the spectrum of frequencies of electromagnetic radiation generated by molecular electrons making transitions to lower energy states Thermal emission, electromagnetic radiation generated by the thermal motion of particles in matter List of light sources, including both natural and artificial processes that emit light Emission (radiocommunications), a radio signal (usually modulated) emitted from a radio transmitter Emission coefficient, a coefficient in the power output per unit time of an electromagnetic source Emission line, or "spectral line", a dark or bright line in an otherwise uniform and continuous spectrum Emission nebula, a cloud of ionized gas emitting light of various colors Emission theory (relativity), a competing theory for the special theory of relativity, explaining the results of the Michelson-Morley experiment Emission theory (vision), the proposal that visual perception is accomplished by rays of light emitted by the eyes
Other uses Thermionic emission, the flow of charged particles from a charged metal or a charged metal oxide surface, archaically known as the Edison effect Field emission, the releasing of electrons from a material due to effects of a strong electrostatic field Ejaculation, the ejection of semen from the penis; also, specifically: Nocturnal emission, ejaculation experienced during sleep Noise, emission Exhalation of air, especially in the context of musical instruments
See also Emissions control (disambiguation) Emitter (disambiguation) Emit (disambiguation)