Stratospheric ozone destruction

Chemical Family a group of elements that share similar chemical properties and share the same column in the periodic table, for example, halogens, alkali earth Chirality condition that describes the handedness of a molecule or whether a molecule exists in forms that can be superimposed on each other Chlorofluorocarbons also called CFCs, compounds consisting of chorine, fluorine, and carbon that are responsible for stratospheric ozone destruction Coagulation precipitation or separation from a dispersed state Coefficient of Thermal Expansion measure of the rate at which a substance will expand when heated... 

In Section C.3, we saw that gas-phase chlorine chemistry in the stratosphere is inextricably intertwined with bromine chemistry. Because of this close interrelationship, altering the concentrations of only one of the halogens (e.g., through controls) may not have the proportional quantitative result that might be initially expected. We explore in this section in more detail the role of brominated organics in stratospheric ozone destruction and the interrelationship with chlorine chemistry. 

Daniel JS, Solomon S, Portmann RW, Garcia RR (1999) Stratospheric Ozone Destruction The Importance of Bromine Relative to Chlorine. J Geophys Res 104 23871... 

Cicerone R.J., Stolarski R.S. and Walters S., Stratospheric ozone destruction by manmade chlorofluoromethanes. Science , 186, 1165-1167 (1974). 

In Section 4.6.4, the role of CFCs in stratospheric ozone destruction was discussed. CFCs also are of concern because they are radiatively active in portions of the infrared spectrum not strongly attenuated by water vapor, C02, CH4, or N20. Currently, a CFC molecule added to the atmosphere absorbs about 10,000 times as much long-wave infrared radiation as does a C02 molecule. C02 has a radiative forcing of 1.8 X 10-5 W/(m2 ppb(v)), whereas CFCs range from 0.22 to 0.32 W/(m2 ppb(v)) (Prather et al., 1996). CFCs also have long atmospheric residence times, ranging from 50 to 1700 years. The locations of some CFC absorbance bands are shown in Fig. 4-42. Unlike the several radiatively active trace gases that have both natural and... 

It was not until recently that N2O was recognized as an atmospheric pollutant which contributes to stratospheric ozone destruction and greenhouse effects. This gave more emphasis to the search of active catalysts to decompose N2O. 

In the most common sequence of reactions involved with stratospheric ozone destruction, the CIO- radicals react to form a dimer, which then reacts to regenerate Cl atoms, which in turn react with ozone to regenerate CIO- in the following reaction sequence (where M is an energy-absorbing third body, such as an N2 molecule) ... 

In view of the environmental problems such as the greenhouse effect and stratospheric ozone destruction, mainly caused by chlorofluorocarbons (CFC), the database was extended to thermophysical properties of environmentally acceptable refrigerants (Stephan Krauss 1990). 

Both CIO and Cl involved in the above chain reactions have been detected in the 25 to 45-km altitude region. Also involved as an intermediate in the stratospheric ozone destruction caused by ehlorofluorocarbons is the (C10)2 dimer. 

HFCs, another class of CFC substitutes, do not contribute to stratospheric ozone destruction because they do not contain chlorine or bromine. Some HFCs have long atmospheric residence times, ensuring their presence for many decades to come. Like HCFCs, the radiative efficiencies of HFCs are on the order of 0.2 W/(m ppb(v)) (IPCC, 2013), only slightly less than those... 

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