Search results
Results from the WOW.Com Content Network
Ozone is lost by reaction with atomic oxygen (plus other trace atoms). The ozone–oxygen cycle is the process by which ozone is continually regenerated in Earth's stratosphere, converting ultraviolet radiation (UV) into heat. In 1930 Sydney Chapman resolved the chemistry involved. The process is commonly called the Chapman cycle by atmospheric ...
Essentially all UVC (100–280 nm) is blocked by dioxygen (at 100–200 nm) or by ozone (at 200–280 nm) in the atmosphere. The shorter portion of this band and even more energetic UV causes the formation of the ozone layer, when single oxygen atoms produced by UV photolysis of dioxygen (below 240 nm) react with more dioxygen. The ozone layer ...
The ozone layer contains less than 10 parts per million of ozone, while the average ozone concentration in Earth's atmosphere as a whole is about 0.3 parts per million. The ozone layer is mainly found in the lower portion of the stratosphere, from approximately 15 to 35 kilometers (9 to 22 mi) above Earth, although its thickness varies ...
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]
In this layer ozone concentrations are about 2 to 8 parts per million, which is much higher than in the lower atmosphere but still very small compared to the main components of the atmosphere. It is mainly located in the lower portion of the stratosphere from about 15–35 km (9.3–21.7 mi; 49,000–115,000 ft), though the thickness varies ...
The atmosphere is 21% oxygen by volume, which equates to a total of roughly 34 × 10 18 mol of oxygen. [2] Other oxygen-containing molecules in the atmosphere include ozone (O 3), carbon dioxide (CO 2), water vapor (H 2 O), and sulphur and nitrogen oxides (SO 2, NO, N 2 O, etc.).
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.
2 starts to gas out of the oceans, but is absorbed by land surfaces and formation of ozone layer; 4–5) O 2 sinks filled and the gas accumulates. Free oxygen gas was almost nonexistent in Earth's atmosphere before photosynthetic archaea and bacteria evolved, probably about 3.5 billion years ago.