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  2. Ozone layer - Wikipedia

    en.wikipedia.org/wiki/Ozone_layer

    The ozone layer visible from space at Earth's horizon as a blue band of afterglow within the bottom of the large bright blue band that is the stratosphere, with a silhouette of a cumulonimbus in the orange afterglow of the troposphere. The ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet ...

  3. Ground-level ozone - Wikipedia

    en.wikipedia.org/wiki/Ground-level_ozone

    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.

  4. Null cycle - Wikipedia

    en.wikipedia.org/wiki/Null_cycle

    One example is the null cycle that occurs during the day between NO x and ozone. Tropospheric Null Cycle O 3 + NO → O 2 + NO 2. NO 2 + hν → NO + O(3 P) O (3 P) + O 2 + M → O 3 + M Net: hv → H This cycle links ozone to NOx in the troposphere during daytime. In equilibrium, described by the Leighton relationship, solar radiation and the ...

  5. Geological history of oxygen - Wikipedia

    en.wikipedia.org/wiki/Geological_history_of_oxygen

    Stage 1 (3.85–2.45 Ga): Practically no O 2 in the atmosphere. Stage 2 (2.45–1.85 Ga): O 2 produced, but absorbed in oceans and seabed rock. Stage 3 (1.85–0.85 Ga): O 2 starts to gas out of the oceans, but is absorbed by land surfaces and formation of ozone layer. Stages 4 and 5 (0.85 Ga–present): O 2 sinks filled, the gas accumulates. [1]

  6. Ozone depletion - Wikipedia

    en.wikipedia.org/wiki/Ozone_depletion

    Following the ozone depletion in 1997 and 2011, a 90% drop in ozone was measured by weather balloons over the Arctic in March 2020, as they normally recorded 3.5 parts per million of ozone, compared to only around 0.3 parts per million lastly, due to the coldest temperatures ever recorded since 1979, and a strong polar vortex which allowed ...

  7. UN says ozone layer slowly healing, hole to mend by 2066

    www.aol.com/news/un-says-ozone-layer-slowly...

    Earth’s protective ozone layer is slowly but noticeably healing at a pace that would fully mend the hole over Antarctica in about 43 years, a new United Nations report says. A once-every-four ...

  8. Leighton relationship - Wikipedia

    en.wikipedia.org/wiki/Leighton_relationship

    This series of reactions creates a null cycle, in which there is no net production or loss of any species involved. Since O(3 P) is very reactive and O 2 is abundant, O(3 P) can be assumed to be in steady state, and thus an equation linking the concentrations of the species involved can be derived, giving the Leighton relationship: [2] [3]

  9. Tropospheric ozone depletion events - Wikipedia

    en.wikipedia.org/wiki/Tropospheric_ozone...

    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 ...