Emission

Emission may refer to:

• Emission of Air pollution, 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

• 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

• Thermionic emission, the flow of charged particles called thermions from a charged metal or a charged metal oxide surface, archaically known as the Edison effect
• 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

• Emissions control (disambiguation)
• Emitter (disambiguation)
• Emit (disambiguation)