emission
emission — noun
1. the process by which a substance such as gas, heat, light, or radiation is sent
the process by which a substance such as gas, heat, light, or radiation is sent out or released from a source
The emission of heat from the engine caused the metal parts to expand.
emission of [heat/gas/light] — uncountable, general process
Felipe's research focused on the emission of light from certain chemical reactions.
The new filter system reduces the emission of harmful gases into the atmosphere.
The sensor detected an emission of methane gas just before midnight.
- absorption
the process of taking in rather than sending out
文法句型
emission of [gas/heat/light/radiation]
the emission of [substance]
用法筆記
When referring to the general process, this sense is usually uncountable (e.g., 'the emission of heat'). For a single specific instance, it can be countable (e.g., 'an emission of smoke').
常見錯誤
2. a specific amount of gas, especially carbon dioxide, that is produced and releas
a specific amount of gas, especially carbon dioxide, that is produced and released into the air, often measured for environmental or regulatory purposes
The government set strict limits on carbon emissions from cars.
countable noun: carbon emissions / CO₂ emissions
Hyun checked the factory's CO₂ emissions on the monitor every morning.
Mei watched methane emissions rise on her tablet as the dairy cows entered the barn.
Wei watched the monitor as the hybrid bus's CO₂ emissions dropped below the target.
文法句型
[modifier] + emissions
reduce/cut/limit + emissions
用法筆記
Almost always used in the plural form (emissions) when referring to measurable quantities. The singular (an emission) is rare outside scientific contexts.
常見錯誤
3. harmful substances, especially gases or small particles, that are released into
harmful substances, especially gases or small particles, that are released into the air by vehicles, factories, or power stations and damage the environment or human health
The factory must clean its emissions before releasing them into the air.
countable plural: factory emissions
Diesel emissions contain tiny particles that are bad for human health.
Thick black emissions from the factory chimney drifted over the school playground.
Yael fitted a new filter to reduce her truck's harmful exhaust emissions.
- pollutants
directly names the harmful quality; more specific
- exhaust fumes
informal; limited to vehicle emissions
文法句型
industrial/vehicle/factory + emissions
emissions + contain/produce/cause
用法筆記
Frequently appears in news and political discussions about climate change and air quality. Focuses on the harmfulness of the substances, unlike sense 4 which is broader in scope.
常見錯誤
4. any solid, liquid, or gaseous substance that is released into the air from a nat
any solid, liquid, or gaseous substance that is released into the air from a natural or man-made source, not necessarily harmful
Volcanic emissions include ash, sulfur dioxide, and water vapor.
natural source: volcanic emissions
Dr. Nakamura sealed a sample of the chemical plant's airborne emissions in a glass jar.
The eucalyptus grove released a white haze of natural emissions into the warm morning air.
Nora collected samples of gaseous emissions from the volcano's crater.
文法句型
[source-type] + emissions
volcanic/natural/chemical + emissions
用法筆記
Broader than the environmental sense (sense 3). This sense includes natural emissions such as volcanic gases or plant vapours, which are not necessarily harmful. More common in scientific or technical writing.
5. a fluid or substance that an animal or human body releases, either as a normal p
a fluid or substance that an animal or human body releases, either as a normal process or as a sign of illness
The patient's nasal emissions were tested for signs of infection.
medical register: nasal emissions
The doctor checked the bodily emissions for signs of a stomach problem.
Certain medications can reduce the emission of stomach acid at night.
When Keiko woke up, yellow emissions had crusted along her eyelashes.
文法句型
[body-part] + emissions
nasal/ocular/intestinal + emissions
用法筆記
Very formal or medical register. In everyday conversation, words like 'discharge' or 'waste' are far more common. Typically used by doctors in clinical reports.