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Ozone depletion also explains much of the observed reduction in stratospheric and upper tropospheric temperatures. [33] [34] The source of the warmth of the stratosphere is the absorption of UV radiation by ozone, hence reduced ozone leads to cooling. Some stratospheric cooling is also predicted from increases in greenhouse gases such as CO
It is stratospheric chlorine that affects ozone depletion. Only methyl chloride, which is one of the halocarbons, has a mainly natural source, [40] and it is responsible for about 20% of the chlorine in the stratosphere; the remaining 80% comes from man-made sources. [41]
Ozone in the troposhere is determined by photochemical production and destruction, dry deposition and cross-tropopause transport of ozone from the stratosphere. [2] In the Arctic troposphere, transport and photochemical reactions involving nitrogen oxides and volatile organic compounds (VOCs) as a result of human emissions also produce ozone resulting in a background mixing ratio of 30 to 50 ...
Ground-level ozone (O 3), also known as surface-level ozone and tropospheric ozone, is a trace gas in the troposphere (the lowest level of the Earth's atmosphere), with an average concentration of 20–30 parts per billion by volume (ppbv), with close to 100 ppbv in polluted areas.
The ozone layer is on track to fully recover from its depletion within the next four decades, a panel of scientists gathered by the United Nations said on Monday. U.N.: Depletion of ozone layer ...
The ozone at ground level is primarily from fossil fuel precursors, but methane is a natural precursor, and the very low natural background level of ozone at ground level is considered safe. This section examines the health impacts of fossil fuel burning, which raises ground level ozone far above background levels.
VSLS are ozone-depleting halogen-containing substances found in the stratosphere. These substances have very short lifetimes, typically less than 6 months. [1] Approximately 90% of VSLS are produced by natural processes and their rate of production is increasing. “They are bromine compounds produced by seaweed and the ocean's phytoplankton”.
Pictured left: Image of the largest Antarctic ozone hole ever recorded (September 2006). Ozone depletion consists of two related events observed since the late 1970s: a steady lowering of about four percent in the total amount of ozone in Earth's atmosphere, and a much larger springtime decrease in stratospheric ozone (the ozone layer) around Earth's polar regions.