query: which layer of the atmosphere is the ozone layer located

pos: Ozone layer Ozone layer The Ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation. It contains high concentrations of ozone (O) in relation to other parts of the atmosphere, although still small in relation to other gases in the stratosphere. 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 above Earth, although its thickness varies seasonally and

pos: Ozone layer 28, 2003, which operated until early 2012. Ozone layer The Ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation. It contains high concentrations of ozone (O) in relation to other parts of the atmosphere, although still small in relation to other gases in the stratosphere. 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 above

pos: Ozone layer Ozone layer The Ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation. It contains high concentrations of ozone (O) in relation to other parts of the atmosphere, although still small in relation to other gases in the stratosphere. 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 above Earth, although its thickness varies seasonally and

pos: Ozone layer applications. These replacement compounds are more reactive and less likely to survive long enough in the atmosphere to reach the stratosphere where they could affect the ozone layer. While being less damaging than CFCs, HCFCs can have a negative impact on the ozone layer, so they are also being phased out. These in turn are being replaced by hydrofluorocarbons (HFCs) and other compounds that do not destroy stratospheric ozone at all. The residual effects of CFCs accumulating within the atmosphere lead to a concentration gradient between the atmosphere and the ocean. This organohalogen compound is able to dissolve into the

pos: Tropospheric ozone Tropospheric ozone Ozone (O) is a trace gas of the troposphere, with an average concentration of 20-30 parts per billion by volume (ppbv), with close to 100 ppbv in polluted areas. . Ozone is also an important constituent of the stratosphere, where the ozone layer exists. The troposphere is the lowest layer of the Earth's atmosphere. It extends from the ground up to a variable height of approximately 14 kilometers above sea level. Ozone is least concentrated in the ground layer (or planetary boundary layer) of the troposphere. It's concentration increases as height above sea level increases, with a maximum

pos: Atmosphere The lowest layer is the troposphere, which extends from the surface to the bottom of the stratosphere. Three quarters of the atmosphere's mass resides within the troposphere, and is the layer within which the Earth's terrestrial weather develops. The depth of this layer varies between 17 km at the equator to 7 km at the poles. The stratosphere, extending from the top of the troposphere to the bottom of the mesosphere, contains the ozone layer. The ozone layer ranges in altitude between 15 and 35 km, and is where most of the ultraviolet radiation from the Sun is absorbed. The

pos: Ozone as concentrations in μg/m. The study of ozone concentration in the atmosphere started in the 1920s. The highest levels of ozone in the atmosphere are in the stratosphere, in a region also known as the ozone layer between about 10 km and 50 km above the surface (or between about 6 and 31 miles). However, even in this "layer", the ozone concentrations are only two to eight parts per million, so most of the oxygen there is dioxygen, O, at about 210,000 parts per million by volume. Ozone in the stratosphere is mostly produced from short-wave ultraviolet rays between 240

pos: Atmosphere of Earth and balloons, and too low to permit orbital spacecraft. The mesosphere is mainly accessed by sounding rockets and rocket-powered aircraft. The stratosphere is the second-lowest layer of Earth's atmosphere. It lies above the troposphere and is separated from it by the tropopause. This layer extends from the top of the troposphere at roughly above Earth's surface to the stratopause at an altitude of about . The atmospheric pressure at the top of the stratosphere is roughly 1/1000 the pressure at sea level. It contains the ozone layer, which is the part of Earth's atmosphere that contains relatively high concentrations of

pos: Ozone layer called the ozone-oxygen cycle. Chemically, this can be described as: About 90 percent of the ozone in the atmosphere is contained in the stratosphere. Ozone concentrations are greatest between about , where they range from about 2 to 8 parts per million. If all of the ozone were compressed to the pressure of the air at sea level, it would be only thick. Although the concentration of the ozone in the ozone layer is very small, it is vitally important to life because it absorbs biologically harmful ultraviolet (UV) radiation coming from the sun. Extremely short or vacuum UV (10–100

pos: Ozone layer stratospheric wind patterns. In the northern hemisphere these patterns, known as the Brewer-Dobson circulation, make the ozone layer thickest in the spring and thinnest in the fall. When ozone in produced by solar UV radiation in the tropics, it is done so by circulation lifting ozone-poor air out of the troposphere and into the stratosphere where the sun photolyzes oxygen molecules and turns them into ozone. Then, the ozone-rich air is carried to higher latitudes and drops into lower layers of the atmosphere. Research has found that the ozone levels in the United States are highest in the spring months

pos: Ozone Ozone Ozone , or trioxygen, is an inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , breaking down in the lower atmosphere to or dioxygen. Ozone is formed from dioxygen by the action of ultraviolet light (UV) and electrical discharges within the Earth's atmosphere. It is present in very low concentrations throughout the latter, with its highest concentration high in the ozone layer of the stratosphere, which absorbs most of the Sun's ultraviolet (UV) radiation.

pos: Ozone layer upper-atmosphere ozone-depletion rate slowed down significantly during the previous decade. Some breakdown can be expected to continue because of ODSs used by nations which have not banned them, and because of gases which are already in the stratosphere. Some ODSs, including CFCs, have very long atmospheric lifetimes, ranging from 50 to over 100 years. It has been estimated that the ozone layer will recover to 1980 levels near the middle of the 21st century. A gradual trend toward "healing" was reported in 2016. Compounds containing C–H bonds (such as hydrochlorofluorocarbons, or HCFCs) have been designed to replace CFCs in certain

pos: Oxygen cycle These numbers are based primarily on estimates from (Walker, J. C. G.): Table 1: Major reservoirs involved in the oxygen cycle <br> Table 2: Annual gain and loss of atmospheric oxygen (Units of 10 kg O per year) The presence of atmospheric oxygen has led to the formation of ozone (O) and the ozone layer within the stratosphere: The ozone layer is extremely important to modern life as it absorbs harmful ultraviolet radiation: , http://paos.colorado.edu/~fasullo/pjw_class/oxygencycle.html Oxygen cycle The oxygen cycle is the biogeochemical cycle of oxygen within its four main reservoirs: the atmosphere (air), the total content of biological matter

pos: Photodissociation the ozone layer is also caused by photodissociation. Ozone in the Earth's stratosphere is created by ultraviolet light striking oxygen molecules containing two oxygen atoms (O), splitting them into individual oxygen atoms (atomic oxygen). The atomic oxygen then combines with unbroken O to create ozone, O. In addition, photolysis is the process by which CFCs are broken down in the upper atmosphere to form ozone-destroying chlorine free radicals. In astrophysics, photodissociation is one of the major processes through which molecules are broken down (but new molecules are being formed). Because of the vacuum of the interstellar medium, molecules and free

pos: Ozone depletion substances (ODS). These compounds are transported into the stratosphere by the winds after being emitted from the surface. Once in the stratosphere, they release halogen atoms through photodissociation, which catalyze the breakdown of ozone (O) into oxygen (O). Both types of ozone depletion were observed to increase as emissions of halocarbons increased. Ozone depletion and the ozone hole have generated worldwide concern over increased cancer risks and other negative effects. The ozone layer prevents most harmful UVB wavelengths of ultraviolet light (UV light) from passing through the Earth's atmosphere. These wavelengths cause skin cancer, sunburn and cataracts, which were projected

pos: Earth full range of temperature on Earth. Above the troposphere, the atmosphere is usually divided into the stratosphere, mesosphere, and thermosphere. Each layer has a different lapse rate, defining the rate of change in temperature with height. Beyond these, the exosphere thins out into the magnetosphere, where the geomagnetic fields interact with the solar wind. Within the stratosphere is the ozone layer, a component that partially shields the surface from ultraviolet light and thus is important for life on Earth. The Kármán line, defined as 100 km above Earth's surface, is a working definition for the boundary between the atmosphere and

pos: Tropospheric ozone spectrum, the most common way to measure ozone is to measure how much of this light spectrum is absorbed in the atmosphere. Because the stratosphere has higher ozone concentration than the troposphere, it is important for remote sensing instruments to be able to determine altitude along with the concentration measurements. The TOMS-EP instrument aboard a satellite from NASA is an example of an ozone layer measuring satellite , and TES is an example of an ozone measuring satellite that is specifically for the troposphere. Lidar is a common ground based remote sensing technique to measure ozone. TOLnet is the network

pos: Atmosphere of Earth that gas. The stratosphere defines a layer in which temperatures rise with increasing altitude. This rise in temperature is caused by the absorption of ultraviolet radiation (UV) radiation from the Sun by the ozone layer, which restricts turbulence and mixing. Although the temperature may be at the tropopause, the top of the stratosphere is much warmer, and may be near 0 °C. The stratospheric temperature profile creates very stable atmospheric conditions, so the stratosphere lacks the weather-producing air turbulence that is so prevalent in the troposphere. Consequently, the stratosphere is almost completely free of clouds and other forms of weather.

pos: Solar Mesosphere Explorer Solar Mesosphere Explorer The Solar Mesosphere Explorer (also known as Explorer 64) was a United States unmanned spacecraft to investigate the processes that create and destroy ozone in Earth's upper atmosphere. The mesosphere is a layer of the atmosphere extending from the top of the stratosphere to an altitude of about . The spacecraft carried five instruments to measure ozone, water vapor and incoming solar radiation. Launched on October 6, 1981, on a Delta rocket from Vandenberg Air Force Base, in California, the satellite returned data until April 4, 1989. The spacecraft reentered Earth's atmosphere on March 5, 1991. Managed

pos: Mario J. Molina of ozone, CFCs and atmospheric conditions with computer modelling. First Molina tried to figure out how CFCs could be decomposed. At lower levels of the atmosphere, they were inert. Molina realized that if CFCs released into the atmosphere do not decay by other processes, they will continually rise to higher altitudes. Higher in the atmosphere, different conditions apply. The highest levels of the stratosphere are exposed to the sun’s ultraviolet light. A thin layer of ozone floating high in the stratosphere protects lower levels of the atmosphere from that type of radiation. Molina theorized that photons from ultraviolet light, known

pos: Chlorine monoxide many countries, CFCs can stay in the atmosphere for about 50-500 years. This cause many chlorine radicals to be produced and hence a significant amount of ozone molecules are decomposed before the chlorine radicals are able to react with chlorine monoxide to form Dichlorine monoxide. Chlorine monoxide Chlorine monoxide is a chemical radical with the chemical formula ClO. It plays an important role in the process of ozone depletion. In the stratosphere, chlorine atoms react with ozone molecules to form chlorine monoxide and oxygen. This reaction causes the depletion of the ozone layer. This reaction can go on and the

pos: Stratospheric Aerosol and Gas Experiment ultraviolet/visible energy and this is converted via algorithms to determine chemical concentrations. SAGE data has been used to study the atmospheres aerosols, ozone, water vapor, and other trace gases. There has been 3 series of SAGE instruments. Stratospheric Aerosol and Gas Experiment The Stratospheric Aerosol and Gas Experiment (SAGE) is a series of remote sensing satellite instruments used to study the chemical composition of earth's atmosphere. Specifically, SAGE has been used to study the Earth's ozone layer and aerosols at the troposphere through the stratosphere. The SAGE instruments use solar occultation measurement technique to determine chemical concentrations in the atmosphere.

pos: Stratosphere Stratosphere The stratosphere () is the second major layer of Earth's atmosphere, just above the troposphere, and below the mesosphere. The stratosphere is stratified in temperature, with warmer layers higher and cooler layers closer to the Earth; this increase of temperature with altitude is a result of the absorption of the Sun's ultraviolet radiation by the ozone layer. This is in contrast to the troposphere, near the Earth's surface, where temperature decreases with altitude. The border between the troposphere and stratosphere, the tropopause, marks where this temperature inversion begins. Near the equator, the stratosphere starts at as high as ,

pos: Air conditioning eventually reach the upper atmosphere. Once the refrigerant reaches the stratosphere, UV radiation from the Sun homolytically cleaves the chlorine-carbon bond, yielding a chlorine radical. These chlorine radicals catalyze the breakdown of ozone into diatomic oxygen, depleting the ozone layer that shields the Earth's surface from strong UV radiation. Each chlorine radical remains active as a catalyst until it binds with another radical, forming a stable molecule and quenching the chain reaction. Prior to 1994, most automotive air conditioning systems used R-12 as a refrigerant. It was replaced with R-134a refrigerant, which has no ozone depletion potential. Old R-12 systems

pos: Ozone depletion nitrous oxide emissions over the natural background, which would in turn result in an increase in the amount of NO in the stratosphere. Thus human activity could affect the stratospheric ozone layer. In the following year, Crutzen and (independently) Harold Johnston suggested that NO emissions from supersonic passenger aircraft, which would fly in the lower stratosphere, could also deplete the ozone layer. However, more recent analysis in 1995 by David W. Fahey, an atmospheric scientist at the National Oceanic and Atmospheric Administration, found that the drop in ozone would be from 1–2 percent if a fleet of 500 supersonic passenger

pos: Ozone layer an altitude of 100 kilometers from the planet's surface. The photochemical mechanisms that give rise to the ozone layer were discovered by the British physicist Sydney Chapman in 1930. Ozone in the Earth's stratosphere is created by ultraviolet light striking ordinary oxygen molecules containing two oxygen atoms (O), splitting them into individual oxygen atoms (atomic oxygen); the atomic oxygen then combines with unbroken O to create ozone, O. The ozone molecule is unstable (although, in the stratosphere, long-lived) and when ultraviolet light hits ozone it splits into a molecule of O and an individual atom of oxygen, a continuing process

pos: Vapor-compression refrigeration replaced, such as sulfur dioxide. Haloalkanes are also an order(s) of magnitude more expensive than petroleum derived flammable alkanes of similar or better cooling performance. Unfortunately, chlorine- and fluorine-bearing refrigerants reach the upper atmosphere when they escape. In the stratosphere, CFCs break up due to UV radiation, releasing their chlorine free radicals. These chlorine free radicals act as catalysts in the breakdown of ozone through chain reactions. One CFC molecule can cause thousands of ozone molecules to break down. This causes severe damage to the ozone layer that shields the Earth's surface from the Sun's strong UV radiation, and has

neg: Ozone Action Day very different sources, atmospheric chemistry, and affect human health differently as well. The ozone layer protects people from the sun's most damaging ultraviolet rays. Because the ozone layer is located high in the atmosphere, people are not directly exposed to it. Ground-level ozone, however, is a health hazard because people breathe it. It is formed through a complex set of chemical reactions involving hydrocarbons, nitrogen oxides and sunlight on calm summer days where the weather may also be warm and humid. High levels of ground ozone affect the breathing process and aggravate asthma in chronic sufferers. The young, elderly, and

neg: Vienna Convention for the Protection of the Ozone Layer Vienna Convention for the Protection of the Ozone Layer The Vienna Convention for the Protection of the Ozone Layer is a multilateral environmental agreement signed in 1985 that provided frameworks for international reductions in the production of chlorofluorocarbons due to their contribution to the destruction of the ozone layer and resulting increase in the threat of skin cancer. During the 1970's, research indicated that man-made chlorofluorocarbons (CFCs) reduce and convert ozone molecules in the atmosphere. CFCs are stable molecules composed of carbon, fluorine, and chlorine that were used prominently in products such as refrigerators. The threats associated with reduced ozone

neg: Atmosphere of Mars Express has shown the presence of two distinct ozone layers at low-to-mid latitudes. These comprise a persistent, near-surface layer below an altitude of 30 km, a separate layer that is only present in northern spring and summer with an altitude varying from 30 to 60 km, and another separate layer that exists 40–60 km above the southern pole in winter, with no counterpart above the Mars's north pole. This third ozone layer shows an abrupt decrease in elevation between 75 and 50 degrees south. SPICAM detected a gradual increase in ozone concentration at 50 km until midwinter, after which it

neg: Views of Lyndon LaRouche and the LaRouche movement Science & Technology", which conducted what has been called "a very effective campaign of misinformation on the issue of ozone depletion", published "The Holes in the Ozone Scare" in 1992. The book, by LaRouche followers Rogelio Maduro and Ralf Schauerhammer, said that chlorofluorocarbons (CFCs) were not destroying the ozone layer and opposed the proposal to ban them. It asserted that most chlorine in the atmosphere came from oceans, volcanoes, or other natural sources, and that CFCs were too heavy to reach the ozone layer. It went on to say that even if the ozone layer were depleted there would not

neg: Ozone depletion increases in surface UVB, there is no direct observational evidence linking ozone depletion to higher incidence of skin cancer and eye damage in human beings. This is partly because UVA, which has also been implicated in some forms of skin cancer, is not absorbed by ozone, and because it is nearly impossible to control statistics for lifestyle changes over time. Ozone, while a minority constituent in Earth's atmosphere, is responsible for most of the absorption of UVB radiation. The amount of UVB radiation that penetrates through the ozone layer decreases exponentially with the slant-path thickness and density of the layer.

neg: Period 2 element can form an allotrope known as ozone. Ozone is a triatomic gas even more reactive than oxygen. Unlike regular diatomic oxygen, ozone is a toxic material generally considered a pollutant. In the upper atmosphere, some oxygen forms ozone which has the property of absorbing dangerous ultraviolet rays within the ozone layer. Land life was impossible before the formation of an ozone layer. Fluorine is the chemical element with atomic number 9. It occurs naturally in its only stable form F. Fluorine is a pale-yellow, diatomic gas under normal conditions and down to very low temperatures. Short one electron of the

neg: Aerosol spray ozone layer. In response to this theory, the U.S. Congress passed amendments to the Clean Air Act in 1977 authorizing the Environmental Protection Agency to regulate the presence of CFCs in the atmosphere. The United Nations Environment Programme called for ozone layer research that same year, and, in 1981, authorized a global framework convention on ozone layer protection. In 1985, Joe Farman, Brian G. Gardiner, and Jon Shanklin published the first scientific paper detailing the hole in the ozone layer. That same year, the Vienna Convention was signed in response to the UN's authorization. Two years later, the Montreal Protocol,

neg: Stratospheric sulfur aerosols and then the Arctic. These holes in the ozone layer have the potential to expand to cover inhabited and vegetative regions of the planet, leading to catastrophic environmental damage. Ozone destruction occurs principally in polar regions, but the formation of ozone occurs principally in the tropics. Ozone is distributed around the planet by the Brewer-Dobson circulation. Therefore, the source and dispersal pattern of aerosols is critical in understanding their effect on the ozone layer. Aerosols scatter light, which affects the appearance of the sky and of sunsets. Changing the concentration of aerosols in the atmosphere can dramatically affect the appearance

neg: History of Earth layer near the upper part of the atmosphere. The ozone layer absorbed, and still absorbs, a significant amount of the ultraviolet radiation that once had passed through the atmosphere. It allowed cells to colonize the surface of the ocean and eventually the land: without the ozone layer, ultraviolet radiation bombarding land and sea would have caused unsustainable levels of mutation in exposed cells. Photosynthesis had another major impact. Oxygen was toxic; much life on Earth probably died out as its levels rose in what is known as the "oxygen catastrophe". Resistant forms survived and thrived, and some developed the ability

neg: Dobson unit squared. Dobson unit The Dobson unit (DU) is a unit of measurement of the amount of a trace gas in a vertical column through the Earth's atmosphere. It originated, and continues to be primarily used in respect to, atmospheric ozone, whose total column amount, usually termed "total ozone", and sometimes "column abundance", is dominated by the high concentrations of ozone in the stratospheric ozone layer. The Dobson Unit is defined as the thickness (in units of 10 µm) of that layer of pure gas which would be formed by the total column amount at standard conditions for temperature and pressure

neg: Dobson unit Dobson unit The Dobson unit (DU) is a unit of measurement of the amount of a trace gas in a vertical column through the Earth's atmosphere. It originated, and continues to be primarily used in respect to, atmospheric ozone, whose total column amount, usually termed "total ozone", and sometimes "column abundance", is dominated by the high concentrations of ozone in the stratospheric ozone layer. The Dobson Unit is defined as the thickness (in units of 10 µm) of that layer of pure gas which would be formed by the total column amount at standard conditions for temperature and pressure (STP).

neg: Ozone depletion as the International Day for the Preservation of the Ozone Layer, or "World Ozone Day", to commemorate the signing of the Montreal Protocol on that date in 1987. Ozone depletion Ozone depletion describes 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 (the ozone layer), and a much larger springtime decrease in stratospheric ozone around Earth's polar regions. The latter phenomenon is referred to as the ozone hole. There are also springtime polar tropospheric ozone depletion events in addition to these stratospheric events. The main

neg: Ozone layer ocean's surface waters and is able to act as a time-dependent tracer. This tracer helps scientists study ocean circulation by tracing biological, physical and chemical pathways As ozone in the atmosphere prevents most energetic ultraviolet radiation reaching the surface of the Earth, astronomical data in these wavelengths have to be gathered from satellites orbiting above the atmosphere and ozone layer. Most of the light from young hot stars is in the ultraviolet and so study of these wavelengths is important for studying the origins of galaxies. The Galaxy Evolution Explorer, GALEX, is an orbiting ultraviolet space telescope launched on April

neg: Eta Carinae potentially the brightest supernova in recorded history (currently SN 1006). At 7,500 light-years from the star it is unlikely to directly affect terrestrial lifeforms, as they will be protected from gamma rays by the atmosphere and from some other cosmic rays by the magnetosphere. The main damage would be restricted to the upper atmosphere, the ozone layer, spacecraft, including satellites, and any astronauts in space. At least one paper has projected that complete loss of the Earth's ozone layer is a plausible consequence of a supernova, which would result in a significant increase in UV radiation reaching Earth's surface from

neg: Earth's magnetic field the charged particles of the solar wind and cosmic rays that would otherwise strip away the upper atmosphere, including the ozone layer that protects the Earth from harmful ultraviolet radiation. The Earth's magnetic field serves to deflect most of the solar wind, whose charged particles would otherwise strip away the ozone layer that protects the Earth from harmful ultraviolet radiation. One stripping mechanism is for gas to be caught in bubbles of magnetic field, which are ripped off by solar winds. Calculations of the loss of carbon dioxide from the atmosphere of Mars, resulting from scavenging of ions by the

neg: Earth ozone layer due to the subsequent conversion of atmospheric into. The ozone layer blocks ultraviolet solar radiation, permitting life on land. Other atmospheric functions important to life include transporting water vapor, providing useful gases, causing small meteors to burn up before they strike the surface, and moderating temperature. This last phenomenon is known as the greenhouse effect: trace molecules within the atmosphere serve to capture thermal energy emitted from the ground, thereby raising the average temperature. Water vapor, carbon dioxide, methane, nitrous oxide, and ozone are the primary greenhouse gases in the atmosphere. Without this heat-retention effect, the average surface

neg: Ozone layer The ozone layer (which absorbs from about 200 nm to 310 nm with a maximal absorption at about 250 nm) is very effective at screening out UV-B; for radiation with a wavelength of 290 nm, the intensity at the top of the atmosphere is 350 million times stronger than at the Earth's surface. Nevertheless, some UV-B, particularly at its longest wavelengths, reaches the surface, and is important for the skin's production of vitamin D. Ozone is transparent to most UV-A, so most of this longer-wavelength UV radiation reaches the surface, and it constitutes most of the UV reaching the Earth.

neg: Robert Strutt, 4th Baron Rayleigh by his apparatus reacted with quicksilver to produce explosive mercury nitride. In 1916, working with his colleague Alfred Fowler, Strutt was the first to prove the existence of ozone in the atmosphere by examining the ultra-violet spectrum of the setting sun. Strutt proved that the ozone was mainly located in the upper atmosphere, in what is now called the ozone layer. Following the death of his father in 1919, Strutt resigned his chair at Imperial College but continued to experiment at home in the private laboratory that his father had established in an old stable block. His earlier work on

neg: Earth life forms. The resultant molecular oxygen () accumulated in the atmosphere and due to interaction with ultraviolet solar radiation, formed a protective ozone layer () in the upper atmosphere. The incorporation of smaller cells within larger ones resulted in the development of complex cells called eukaryotes. True multicellular organisms formed as cells within colonies became increasingly specialized. Aided by the absorption of harmful ultraviolet radiation by the ozone layer, life colonized Earth's surface. Among the earliest fossil evidence for life is microbial mat fossils found in 3.48 billion-year-old sandstone in Western Australia, biogenic graphite found in 3.7 billion-year-old metasedimentary rocks

neg: Polar ecology contaminated. This can be due to the transport of oil by large ships. Siberia is one example of a place that has had major pollution in its rivers. Depletion on the ozone layer is one more threat. An ozone hole has been detected above Antarctica. The cause of the depletion of the ozone layer is due to chlorofluorocarbons and other greenhouse gases. The other main reason is due to man made gases that are released into the atmosphere. There are many environmental effects due to this because the gases that are being released five times faster than they are destroyed.

neg: Summer smog in cities and a visible layer, similar to fog. It also causes a health hazard to people and pollutes the troposphere's air. Summer smog Summer smog, which is common in major cities such as London, Birmingham, New York City and Los Angeles, is caused by pollutants, mainly ozone, which collect in large cities, especially during the summer. It is formed when radiation from the sun causes ozone to build up in the lower atmosphere (troposphere), by combining nitrogen oxides and volatile organic compounds. At this point, ozone, which is protective in the upper atmosphere, can become harmful to humans, crops,

neg: Air quality law is the widespread ban on the manufacture of dichlorodifluoromethane (Freon)), formerly the standard refrigerant in automobile air conditioning systems. This substance, often released into the atmosphere unintentionally as a result of refrigerant system leaks, was determined to have a significant ozone depletion potential, and its widespread use to pose a significant threat to the Earth's ozone layer. Its manufacture was prohibited as part of a suite of restrictions adopted internationally in the Montreal Protocol to the Vienna Convention for the Protection of the Ozone Layer. Still another example is the ban on use of asbestos in building construction materials, to

neg: International Day for the Preservation of the Ozone Layer International Day for the Preservation of the Ozone Layer September 16 was designated by the United Nations General Assembly as the International Day for the Preservation of the Ozone Layer. This designation had been made on December 19, 2000, in commemoration of the date, in 1987, on which nations signed the Montreal Protocol on Substances that Deplete the Ozone Layer. In 1994, the UN General Assembly proclaimed 16 September the International Day for the Preservation of the Ozone Layer, commemorating the date of the signing, in 1987, of the Montreal Protocol on Substances that Deplete the Ozone Layer. The closure

neg: Ozone layer which otherwise would potentially damage exposed life forms near the surface. In 1976 atmospheric research revealed that the ozone layer was being depleted by chemicals released by industry, mainly chlorofluorocarbons (CFCs). Concerns that increased UV radiation due to ozone depletion threatened life on Earth, including increased skin cancer in humans and other ecological problems, led to bans on the chemicals, and the latest evidence is that ozone depletion has slowed or stopped. The United Nations General Assembly has designated September 16 as the International Day for the Preservation of the Ozone Layer. Venus also has a thin ozone layer at

neg: A Beautiful Planet calls Earth's atmosphere "a delicate cocoon of air that shields us from our star's radiation." Of course, the atmosphere doesn't completely block electromagnetic radiation from the Sun; without some sunlight reaching the surface, plants could not harvest the Sun's energy, and practically no life as we know it could exist. The atmosphere's ozone layer does filter out much of the harmful ultraviolet light (or "UV rays") produced by the Sun. UV rays can cause skin cancer, and catastrophic damage to the ozone layer may have contributed to Earth's most extensive mass extinction of species ever, the End-Permian extinction (also known

neg: International Day for the Preservation of the Ozone Layer of the hole in the ozone layer was observed 30 years after the protocol was signed. Due to the nature of the gases responsible for ozone depletion their chemical effects are expected to continue for between 50 to 100 years. International Day for the Preservation of the Ozone Layer September 16 was designated by the United Nations General Assembly as the International Day for the Preservation of the Ozone Layer. This designation had been made on December 19, 2000, in commemoration of the date, in 1987, on which nations signed the Montreal Protocol on Substances that Deplete the Ozone Layer.

neg: Radiation by ozone (O) in particular. Ionizing UV therefore does not penetrate Earth's atmosphere to a significant degree, and is sometimes referred to as vacuum ultraviolet. Although present in space, this part of the UV spectrum is not of biological importance, because it does not reach living organisms on Earth. There is a zone of the atmosphere in which ozone absorbs some 98% of non-ionizing but dangerous UV-C and UV-B. This so-called ozone layer starts at about and extends upward. Some of the ultraviolet spectrum that does reach the ground (the part that begins above energies of 3.1 eV, a wavelength

neg: Paleocontinent rock began to rise causing more land area to be at higher elevations which encouraged more ice to stick. However, the time of Rodinia was a time of inactivity in Earth’s atmosphere. Also the atmosphere had little oxygen because Rodinia’s land surface was too harsh of an environment for land plants to flourish, the atmosphere was devoid of Oxygen and the ozone layer was much less extensive which attributed to the harsh land environment. Gondwana was located in the southern hemisphere, with the land mass that makes up current day Antarctica closest to the South Pole. The continent reaches from

neg: Oxygen O with any organic molecule. Due to its energy content, O is used by complex forms of life, such as animals, in cellular respiration. Other aspects of are covered in the remainder of this article. Trioxygen () is usually known as ozone and is a very reactive allotrope of oxygen that is damaging to lung tissue. Ozone is produced in the upper atmosphere when combines with atomic oxygen made by the splitting of by ultraviolet (UV) radiation. Since ozone absorbs strongly in the UV region of the spectrum, the ozone layer of the upper atmosphere functions as a protective radiation

neg:
Montreal Protocol to take off after countries agreed to phase out the use of CFCs in the 1980s, which were found to be destroying the ozone layer. Like CFCs, HCFCs are used for refrigeration, aerosol propellants, foam manufacture and air conditioning. Unlike the CFCs however, most HCFCs are broken down in the lowest part of the atmosphere, and pose a much smaller risk to the ozone layer. Unfortunately HCFCs are also very potent greenhouse gases, despite their very low atmospheric concentrations, measured in parts per trillion (million million).

 The HCFCs are transitional CFCs replacements, used as refrigerants, solvents, blowing agents for plastic

neg: Internal combustion engine the atmosphere by the reaction of and volatile organic compounds in the presence of sunlight. Ground-level ozone is harmful to human health and the environment. Though the same chemical substance, ground-level ozone should not be confused with stratospheric ozone, or the ozone layer, which protects the earth from harmful ultraviolet rays. Carbon fuels contain sulfur and impurities that eventually produce sulfur monoxides (SO) and sulfur dioxide (SO) in the exhaust, which promotes acid rain. In the United States, nitrogen oxides, PM, carbon monoxide, sulphur dioxide, and ozone, are regulated as criteria air pollutants under the Clean Air Act to levels

neg: Institute of Atmospheric Physics AS CR the IAP is defined by the vertical extent of the atmosphere. Types of investigations include theoretical models, numerical simulation, and experiment for the Earth's boundary layer, troposphere, middle atmosphere, ionosphere and magnetosphere. The main research topic areas currently include mesoscale, dynamical, and applied meteorology. Furthermore, the processes of the atmospheric boundary layer are also of interest. In addition, climate variability and climate change are studied. Other research is conducted that concerns the ozone, along with the previously mentioned ionosphere and magnetosphere. Regarding these upper atmosphere domains, the IAP conducts its own satellite experiments. Other research extends into space plasma physics

neg: Ozone layer geographically. The ozone layer was discovered in 1913 by the French physicists Charles Fabry and Henri Buisson. Measurements of the sun showed that the radiation sent out from its surface and reaching the ground on Earth is usually consistent with the spectrum of a black body with a temperature in the range of 5,500–6,000 K (5,227 to 5,727 °C), except that there was no radiation below a wavelength of about 310 nm at the ultraviolet end of the spectrum. It was deduced that the missing radiation was being absorbed by something in the atmosphere. Eventually the spectrum of the missing

neg: Upper Atmosphere Research Satellite accuracy and spatial resolution, and hence to study the structure and dynamics of the region, (ii) To investigate the distribution and variability of water vapour in the middle atmosphere, to determine its role in the atmospheric general circulation, and its sources and sinks in the middle atmosphere, (iii) To measure the global distribution of oxides of nitrogen and hence to investigate their origins and their roles in catalytic cycles which control the amount of ozone in the stratospheric ozone layer. It also made extensive observations of volcanic aerosols and polar stratospheric clouds in the middle atmosphere. The instrument operated from

neg: Ozone depletion Ozone depletion Ozone depletion describes 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 (the ozone layer), and a much larger springtime decrease in stratospheric ozone around Earth's polar regions. The latter phenomenon is referred to as the ozone hole. There are also springtime polar tropospheric ozone depletion events in addition to these stratospheric events. The main cause of ozone depletion and the ozone hole is manufactured chemicals, especially manufactured halocarbon refrigerants, solvents, propellants and foam-blowing agents (chlorofluorocarbons (CFCs), HCFCs, halons), referred to as ozone-depleting

neg: Ozone depletion from the 250 recorded over central Siberia. It is predicted that the thinning layer would affect parts of Scandinavia and Eastern Europe on March 30–31. On October 2, 2011, a study was published in the journal "Nature", which said that between December 2010 and March 2011 up to 80 percent of the ozone in the atmosphere at about above the surface was destroyed. The level of ozone depletion was severe enough that scientists said it could be compared to the ozone hole that forms over Antarctica every winter. According to the study, "for the first time, sufficient loss occurred to

neg: Vienna Convention for the Protection of the Ozone Layer Groups that help facilitate functions under the convention. A Multilateral Fund exists to aid developing nations transition from ozone-depleting chemicals using guidelines under the convention, which is administered by a Multilateral Fund Secretariat. The Multilateral Fund has aided thousands of projects in nearly 150 countries, preventing the usage of roughly 250,000 tons of ozone-depleting chemicals. Vienna Convention for the Protection of the Ozone Layer The Vienna Convention for the Protection of the Ozone Layer is a multilateral environmental agreement signed in 1985 that provided frameworks for international reductions in the production of chlorofluorocarbons due to their contribution to the destruction

neg: Antarctica Earth. Antarctic ice serves as both the shield and the detection medium for the largest neutrino telescope in the world, built below Amundsen–Scott station. Since the 1970s an important focus of study has been the ozone layer in the atmosphere above Antarctica. In 1985, three British scientists working on data they had gathered at Halley Station on the Brunt Ice Shelf discovered the existence of a hole in this layer. It was eventually determined that the destruction of the ozone was caused by chlorofluorocarbons (CFCs) emitted by human products. With the ban of CFCs in the Montreal Protocol of 1989,

neg: F-type main-sequence star atmospheric shielding from the UV radiation, like an ozone layer in the upper atmosphere, in order to protect the lifeforms on the surface. Without the ozone layer life could still theoretically develop on the planet's surface, but it would most likely be confined to the underwater or underground regions. F-type main-sequence star An F-type main-sequence star (F V) is a main-sequence, hydrogen-fusing star of spectral type F and luminosity class V. These stars have from 1.0 to 1.4 times the mass of the Sun and surface temperatures between 6,000 and 7,600 K. This temperature range gives the F-type stars a

neg: 1,1,1,2-Tetrafluoroethane a refrigerant nor is HFC-134a included in the § 7671a listing of class I and class II substances. 1,1,1,2-Tetrafluoroethane first appeared in the early 1990s as a replacement for dichlorodifluoromethane (R-12), which has ozone depleting properties. 1,1,1,2-Tetrafluoroethane has been atmospherically modeled for its impact on depleting ozone and as a contributor to global warming. Research suggests that over the past 10 years the concentration of 1,1,1,2-tetrafluoroethane has increased significantly in the Earth's atmosphere, with a recent study revealing a doubling in atmospheric concentration between 2001 and 2004. It has insignificant ozone depletion potential (ozone layer), significant global warming potential (100-yr

neg: Tropopause World Meteorological Organization: The tropopause as defined above renders as a first-order discontinuity surface, that is, "temperature" as a function of height varies continuously through the atmosphere but the "temperature gradient" does not. The troposphere is the lowest layer of the Earth's atmosphere; it is located right above the planetary boundary layer, and is the layer in which most weather phenomena take place. The troposphere contains the boundary layer, and ranges in height from an average of at the poles, to at the Equator. In the absence of inversions and not considering moisture, the temperature lapse rate for this layer

neg: Environmental degradation is expanding rapidly which goes hand in hand with the degradation of the environment at large measures. Humanity's appetite for needs is disarranging the environment's natural equilibrium. Production industries are venting smoke and discharging chemicals that are polluting water resources. The smoke that is emitted into the atmosphere holds detrimental gases such as carbon monoxide and sulfur dioxide. The high levels of pollution in the atmosphere form layers that are eventually absorbed into the atmosphere. Organic compounds such as chlorofluorocarbons (CFC’s) have generated an unwanted opening in the ozone layer, which emits higher levels of ultraviolet radiation putting the globe

neg: Umkehr effect increases. For a given zenith angle, the scattered light contribution comes from well defined layer of atmosphere, which can be termed as an effective scattering height. The effective scattering height depends on the ozone absorption coefficient and on the solar zenith angle, increasing as with each of these. The effective scattering height will always be higher for shorter wavelength which is more strongly absorbed. As the sun approaches the horizon, the two intensities decreases, but intensity "I" decreasing more rapidly than "I' ". However, when the effective scattering height for the short wavelength is above the ozone maximum, "I" decreases

neg: Metal it would have a height of nearly 700 light years. The magnetic field shields the Earth from the charged particles of the solar wind, and cosmic rays that would otherwise strip away the upper atmosphere (including the ozone layer that limits the transmission of ultraviolet radiation). Metals are often extracted from the Earth by means of mining ores that are rich sources of the requisite elements, such as bauxite. Ore is located by prospecting techniques, followed by the exploration and examination of deposits. Mineral sources are generally divided into surface mines, which are mined by excavation using heavy equipment, and

neg: Ozone layer radiation was matched to only one known chemical, ozone. Its properties were explored in detail by the British meteorologist G. M. B. Dobson, who developed a simple spectrophotometer (the Dobsonmeter) that could be used to measure stratospheric ozone from the ground. Between 1928 and 1958, Dobson established a worldwide network of ozone monitoring stations, which continue to operate to this day. The "Dobson unit", a convenient measure of the amount of ozone overhead, is named in his honor. The ozone layer absorbs 97 to 99 percent of the Sun's medium-frequency ultraviolet light (from about 200 nm to 315 nm wavelength),

neg: Global commons recycling. The 1979 Convention on Long-Range Transboundary Air Pollution, or CLRTAP, is an early international effort to protect and gradually reduce and prevent air pollution. It is implemented by the European Monitoring and Evaluation Programme (EMEP), directed by the United Nations Economic Commission for Europe (UNECE). The Montreal Protocol on Substances that Deplete the Ozone Layer, or Montreal Protocol (a protocol to the Vienna Convention for the Protection of the Ozone Layer), is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances believed to be responsible for ozone depletion. The treaty was

neg: Indoor air quality necessary. Carbon dioxide concentrations in closed or confined rooms can increase to 1,000 ppm within 45 minutes of enclosure. For example, in a sized office, atmospheric carbon dioxide increased from 500 ppm to over 1,000 ppm within 45 minutes of ventilation cessation and closure of windows and doors Ozone is produced by ultraviolet light from the Sun hitting the Earth's atmosphere (especially in the ozone layer), lightning, certain high-voltage electric devices (such as air ionizers), and as a by-product of other types of pollution. Ozone exists in greater concentrations at altitudes commonly flown by passenger jets. Reactions between ozone and

neg: Atmospheric sciences understanding the implications of human-induced perturbations (e.g., increased carbon dioxide concentrations or depletion of the ozone layer) on the global climate. Atmospheric physics is the application of physics to the study of the atmosphere. Atmospheric physicists attempt to model Earth's atmosphere and the atmospheres of the other planets using fluid flow equations, chemical models, radiation balancing, and energy transfer processes in the atmosphere and underlying oceans. In order to model weather systems, atmospheric physicists employ elements of scattering theory, wave propagation models, cloud physics, statistical mechanics and spatial statistics, each of which incorporate high levels of mathematics and physics. Atmospheric

neg: Ozone depletion and climate change dubbed "monumental" and a combined synopsis provided. There are some parallels between atmospheric chemistry and anthropogenic emissions in the discussions which have taken place and the regulatory attempts which have been made. Most important is that the gases causing both problems have long lifetimes after emission to the atmosphere, thus causing problems which are difficult to reverse. However, the Vienna Convention for the Protection of the Ozone Layer and the Montreal Protocol that amended it are seen as success stories, while the Kyoto Protocol on anthropogenic climate change has largely failed. Currently efforts are being undertaken to assess the reasons

neg: Earth System Research Laboratory Air Resources Laboratory. The goal of the Global Monitoring Division (GMD) is to conduct long-term, continuous measurement of atmospheric gases, particles and radiation in order to understand climate forcing, ozone depletion and air quality. This information will be used to support global and regional decisions, climate projections and carbon management. The Physical Sciences Division (PSD) conducts research to understand the physical environment: the atmosphere, ocean, cryosphere, and land in order to improve local to global weather and climate predictions. The Chemical Sciences Division (CSD) studies chemical processes in the Earth's atmosphere that affect climate, air quality, and the ozone layer.

neg: Montreal Protocol global environmental protection". Montreal Protocol The Montreal Protocol on Substances that Deplete the Ozone Layer (a protocol to the Vienna Convention for the Protection of the Ozone Layer) is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances that are responsible for ozone depletion. It was agreed on 26 August 1987, and entered into force on 26 August 1989, followed by a first meeting in Helsinki, May 1989. Since then, it has undergone eight revisions, in 1990 (London), 1991 (Nairobi), 1992 (Copenhagen), 1993 (Bangkok), 1995 (Vienna), 1997 (Montreal), 1998 (Australia), 1999 (Beijing)

neg: Montreal Protocol Montreal Protocol The Montreal Protocol on Substances that Deplete the Ozone Layer (a protocol to the Vienna Convention for the Protection of the Ozone Layer) is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances that are responsible for ozone depletion. It was agreed on 26 August 1987, and entered into force on 26 August 1989, followed by a first meeting in Helsinki, May 1989. Since then, it has undergone eight revisions, in 1990 (London), 1991 (Nairobi), 1992 (Copenhagen), 1993 (Bangkok), 1995 (Vienna), 1997 (Montreal), 1998 (Australia), 1999 (Beijing) and 2016 (Kigali,

neg: Vienna Convention for the Protection of the Ozone Layer the European Union. While not a binding agreement, it acts as a framework for the international efforts to protect the ozone layer; however, it does not include legally binding reduction goals for the use of CFCs, the main chemical agents causing ozone depletion. The treaty's provisions include the international sharing of climate and atmospheric research to promote knowledge of the effects on the ozone layer. In addition, the treaty calls for the adoption of international agencies to assess the harmful effects of depleted ozone and the promotion of policies that regulate the production of harmful substances that influence the ozone

neg: Atmospheric chemistry atmospheric science moved on from studying the composition of air to a consideration of how the concentrations of trace gases in the atmosphere have changed over time and the chemical processes which create and destroy compounds in the air. Two particularly important examples of this were the explanation by Sydney Chapman and Gordon Dobson of how the ozone layer is created and maintained, and the explanation of photochemical smog by Arie Jan Haagen-Smit. Further studies on ozone issues led to the 1995 Nobel Prize in Chemistry award shared between Paul Crutzen, Mario Molina and Frank Sherwood Rowland. In the 21st

neg: Ozone depletion widely reported in the press. The especially rapid ozone depletion in Antarctica had previously been dismissed as a measurement error. Scientific consensus was established after regulation. While the Antarctic ozone hole has a relatively small effect on global ozone, the hole has generated a great deal of public interest because: Since the ozone layer absorbs UVB ultraviolet light from the sun, ozone layer depletion increases surface UVB levels (all else equal), which could lead to damage, including increase in skin cancer. This was the reason for the Montreal Protocol. Although decreases in stratospheric ozone are well-tied to CFCs and to

neg: Atmospheric infrared sounder instrument to observe and study the response of the atmosphere to increased greenhouse gases. The instrument can detect carbon monoxide emissions from the burning of plant materials and animal waste by humans in rainforests and large cities. It can follow giant plumes of this gas moving across the planet from these large burns, allowing scientists to better monitor pollution transport patterns. AIRS provides a global daily 3-D view of Earth's ozone layer, showing how ozone is transported. The instrument also gives scientists their best view of atmospheric ozone in the Antarctic region during the polar winter. AIRS is also able

neg: Atmosphere of Mars slowly decreased to very low concentrations, with no layer detectable above 35 km. The reporting scientists think that the observed polar ozone layers are the result of the same atmospheric circulation pattern that creates a distinct oxygen emission identified in the polar night and also present in Earth's atmosphere. This circulation takes the form of a huge Hadley cell in which warmer air rises and travels toward the south pole before cooling and sinking at higher latitudes. Mars is on a quite elliptical orbit and has a large axial tilt, which causes extreme seasonal variations in temperature amongst the northern

neg: Rare Earth hypothesis the atmosphere is not stripped over time by solar winds. A terrestrial planet of the right size is needed to retain an atmosphere, like Earth and Venus. On Earth, once the giant impact of Theia thinned Earth's atmosphere, other events were needed to make the atmosphere capable of sustaining life. The Late Heavy Bombardment reseeded Earth with water lost after the impact of Theia. The development of an ozone layer formed protection from ultraviolet (UV) sunlight. Nitrogen and carbon dioxide are needed in a correct ratio for life to form. Lightning is needed for nitrogen fixation. The carbon dioxide gas

neg: Javier Cacho Gomez Javier Cacho Gomez Javier Cacho (born 19 December 1952) is a Spanish writer, scientist, physicist and disseminator. He started his scientific work at the National Investigation Commission for Space (CONIE). In the 80's he carried out investigations relating to the study of the Ozone Layer, on which he wrote a book, Antarctic: The Ozone Hole (1989). He has been responsible for the laboratory studies of the atmosphere at the National Institute for Aerospace Technology (INTA) till 2016. In 1986, he was a member of the first Spanish Scientific Expedition to the Antarctic, where he returned the following years -one of

neg: Environmental issues in Wyoming region. Temperature inversions occur when cool air on the ground covered by a layer of warmer air trap volatile organic compounds and nitrous oxides in the lower atmosphere, whose interactions create ozone. According to the Environmental Protection Agency (EPA), winter 2010 saw ozone pollution levels in the Upper Green River Basin of Sublette County, Wyoming surpass the worst days of any major U.S. city. Excessive ozone levels are harmful to human health, especially in children and elderly. These effects include lung damage, worsened asthma, reduced lung capacity, and increased premature deaths. More often citizens have reported ozone effects in the

neg: Javier Cacho Gomez Fram" (Madrid, 2018). Also as a lecturer he has concentrated on the Polar subjects, developing an intense activity among the students. Javier Cacho Gomez Javier Cacho (born 19 December 1952) is a Spanish writer, scientist, physicist and disseminator. He started his scientific work at the National Investigation Commission for Space (CONIE). In the 80's he carried out investigations relating to the study of the Ozone Layer, on which he wrote a book, Antarctic: The Ozone Hole (1989). He has been responsible for the laboratory studies of the atmosphere at the National Institute for Aerospace Technology (INTA) till 2016. In 1986,

neg: Terraforming of Mars Venus has a dense atmosphere, it has only traces of water vapor (20 ppm) as it lacks a large, dipole induced, magnetic field. Earth's ozone layer provides additional protection. Ultraviolet light is blocked before it can dissociate water into hydrogen and oxygen. Restoring the Martian magnetic poles or providing a sufficiently large artificial magnetosphere between the Sun and Mars is considered essential to restoring the Martian atmosphere and flowing liquid water. However this would only tackle one of the ways Mars atmosphere escapes. Mars also loses atmosphere due to thermal mechanisms (shown in the diagram above - see also Atmospheric

neg: Haloalkane Methyl bromide is a controversial fumigant. Only haloalkanes which contain chlorine, bromine, and iodine are a threat to the ozone layer, but fluorinated volatile haloalkanes in theory may have activity as greenhouse gases. Methyl iodide, a naturally occurring substance, however, does not have ozone-depleting properties and the United States Environmental Protection Agency has designated the compound a non-ozone layer depleter. For more information, see Halomethane. Haloalkane or alkyl halides are the compounds which have the general formula "RX" where R is an alkyl or substituted alkyl group and X is a halogen (F, Cl, Br, I). Haloalkanes have been known

neg: Atmosphere of Venus and the upper one between 73–95 km. In the first layer the temperature is nearly constant at 230 K (−43 °C). This layer coincides with the upper cloud deck. In the second layer temperature starts to decrease again reaching about 165 K (−108 °C) at the altitude of 95 km, where mesopause begins. It is the coldest part of the Venusian dayside atmosphere. In the dayside mesopause, which serves as a boundary between the mesophere and thermosphere and is located between 95–120 km, temperature increases to a constant—about 300–400 K (27–127 °C)—value prevalent in the thermosphere. In contrast, the nightside

neg: EcoCute and refrigerators. But from the 1980s CFCs began to lose favor as refrigerant when their damaging effects on the ozone layer were discovered. Two alternative types of refrigerant, hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs), also lost favour when they were identified as greenhouse gases (additionally, HCFCs were found to be more damaging to the ozone layer than originally thought). The Vienna Convention for the Protection of the Ozone Layer, the Montreal Protocol and the Kyoto Protocol call for the complete abandonment of such refrigerants by 2030. In 1989, amid international concern about the effects of chlorofluorocarbons and hydrochlorofluorocarbons on the ozone

neg: Environment Public Authority government institutions were to operate with regards to environmental law and protection of the environment. Kuwait is a country that has committed to the Vienna Convention to protect the Ozone Layer, and the Montreal Protocol concerning exhausted material of Ozone Layer. These conventions brought forth an Ozone layer protection committee that emerged from the Environment Public Authority of Kuwait to analyze and study the provisions of the protocol and convention. The result was a request to issue the following legislative decrees regarding: The Environment Public Authority also played a large role in the implementation of a special division within the

neg: Susan Solomon over Antarctica. In 1986 and 1987 Solomon led the National Ozone Expedition to McMurdo Sound, where the team gathered the evidence to confirm the accelerated reactions. Solomon was the solo leader of the expedition, and the only woman on the team. Her team measured levels of chlorine oxide 100 times higher than expected in the atmosphere, which had been released by the decomposition of chlorofluorocarbons by ultraviolet radiation. Solomon later showed that volcanoes could accelerate the reactions caused by chlorofluorocarbons, and so increase the damage to the ozone layer. Her work formed the basis of the U.N. Montreal Protocol, an

neg: Nature ozone layer plays an important role in depleting the amount of ultraviolet (UV) radiation that reaches the surface. As DNA is readily damaged by UV light, this serves to protect life at the surface. The atmosphere also retains heat during the night, thereby reducing the daily temperature extremes. Terrestrial weather occurs almost exclusively in the lower part of the atmosphere, and serves as a convective system for redistributing heat. Ocean currents are another important factor in determining climate, particularly the major underwater thermohaline circulation which distributes heat energy from the equatorial oceans to the polar regions. These currents help to

neg: Nimbus program understanding of the processes that maintained or destroyed it. They were pretty sure they understood how the layer formed, and they knew from laboratory experiments that halogens could destroy ozone. Finally, weather balloons had revealed that the concentration of ozone in the atmosphere changed over time, and scientists suspected weather phenomena or seasonal change were responsible. But how all of these pieces of information worked together on a global scale was still unclear. Scientists conducted experiments from NASA experimental aircraft and proved that atmospheric chemicals such as the chlorofluorocarbons (CFCs) released from refrigerants and aerosol sprays did destroy ozone. As

neg: Chappuis absorption Chappuis absorption Chappuis absorption refers to the absorption of electromagnetic radiation by ozone, that is especially noticeable in the ozone layer, which absorbs a small part of sunlight in the visible part of the electromagnetic spectrum. The Chappuis absorption bands occur at wavelengths between 400 and 650 nm. Within this range are two absorption maxima of similar height at 575 and 603 nm wavelengths. Compared to the absorption of ultraviolet light by the ozone layer, known as the Hartley and Huggins absorptions, Chappuis absorption is distinctly weaker. Along with Rayleigh scattering, it contributes to the blue color of the sky,

neg: Anoxic event conditions favorable for the production of source rocks on anything other than a local scale. A model put forward by Lee Kump, Alexander Pavlov and Michael Arthur in 2005 suggests that oceanic anoxic events may have been characterized by upwelling of water rich in highly toxic hydrogen sulfide gas, which was then released into the atmosphere. This phenomenon would probably have poisoned plants and animals and caused mass extinctions. Furthermore, it has been proposed that the hydrogen sulfide rose to the upper atmosphere and attacked the ozone layer, which normally blocks the deadly ultraviolet radiation of the Sun. The increased

neg: Stephen O. Andersen protecting the stratospheric ozone layer. At EPA he rose to Deputy Director for Stratospheric Ozone Protection and then transferred to the Climate Protection Partnerships Division, where he was Director of Strategic Climate Projects until his retirement from government in 2009. The timing of Andersen’s arrival at EPA was fortuitous. 1987 proved to be a watershed moment in the effort to stop ozone depletion, which increased risks of skin cancer and threatened to wipe out crops and ecosystems, among many adverse impacts. The Montreal Protocol on Substances that Deplete the Ozone Layer was agreed on 16 September 1987 and created a

neg: Biosensor match up at every nucleotide position—gives rise to a fluorescent signal (a glow) that is then transmitted to a signal generator. Using biological engineering researchers have created many microbial biosensors. An example is the arsenic biosensor. To detect arsenic they use the Ars operon. Using bacteria, researchers can detect pollutants in samples. Because ozone filters out harmful ultraviolet radiation, the discovery of holes in the ozone layer of the earth's atmosphere has raised concern about how much ultraviolet light reaches the earth's surface. Of particular concern are the questions of how deeply into sea water ultraviolet radiation penetrates and how

neg: Extraterrestrial atmosphere 24% helium and 5% other elements by mass. The atmosphere contains trace amounts of methane, water vapor, ammonia, and silicon-based compounds. There are also traces of carbon, ethane, hydrogen sulfide, neon, oxygen, phosphine, and sulfur. The outermost layer of the atmosphere contains crystals of frozen ammonia, possibly underlaid by a thin layer of water. Jupiter is covered with a cloud layer about 50 km deep. The clouds are composed of ammonia crystals and possibly ammonium hydrosulfide. The clouds are located in the tropopause and are arranged into bands of different latitudes, known as tropical regions. These are sub-divided into lighter-hued