Lifetime

Lifetime may refer to:Life expectancy, the length of time a person is alive Mean lifetime, a certain number that characterizes the rate of reduction ("decay") of a particle of an assemblyService life, a product's expected lifetime, or the acceptable period of use in serviceObject lifetime, in object-oriented programming, the time between an object's creation until the object is no longer usedLifetime Television, a cable television network; see also, Lifetime Entertainment Services, Lifetime Movie Network, and Lifetime Real Women
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(n.)
The time that life continues.
  

The lifetime of a greenhouse gas refers to the approximate amount of time it would take for the anthropogenic increment to an atmospheric pollutant concentration to return to its natural level (assuming emissions cease) as a result of either being converted to another chemical compound or being taken out of the atmosphere via a sink. This time depends on the pollutant's sources and sinks as well as its reactivity. The lifetime of a pollutant is often considered in conjunction with the mixing of pollutants in the atmosphere; a long lifetime will allow the pollutant to mix throughout the atmosphere. Average lifetimes can vary from about a week (sulfate aerosols) to more than a century (CFCs, carbon dioxide). See residence time, greenhouse gas.

Noun
1. the period during which something is functional (as between birth and death); "the battery had a short life"; "he lived a long and happy life"
(synonym) life, lifespan
(hypernym) time period, period of time, period
(hyponym) life expectancy
(part-meronym) birth