Ozone in the Atmosphere

Acid rain erodes buildings, particularly those constructed from limestone. It has been reported that the Acropolis in Athens has suffered more deterioration in the last 20 years than in the previous 2000. Acidic gases are produced directly by the combination of oxides of sulfur and oxides of nitrogen with water and also by more complex processes involving unburned hydrocarbons and ozone in the atmosphere. 

Ozone depletion is by no means restricted to the Southern Hemisphere. In the extremely cold winter of 1994-1995, a similar "ozone hole" was found in the Arctic. Beyond that, the concentration of ozone in the atmosphere over parts of Siberia dropped by 40%. 

FIGURE 13.16 A representation of a proposed one-step mechanism for the decomposition of ozone in the atmosphere. This reaction takes place in a single bimolecular collision. 

The chemistry of the stratospheric ozone will be sketched with a very broad brush in order to illustrate some of the characteristics of catalytic reactions. A model for the formation of ozone in the atmosphere was proposed by Chapman and may be represented by the following "oxygen only" mechanism (other aspects of... 

Ozone in the atmosphere is formed by the chemical reaction of atomic and molecular oxygen ... 

A reaction of ozone provides an example of concentration effects. Ozone in the atmosphere near the Earth s surface is a serious pollutant that damages soft tissues such as the lungs. In major urban areas, smog alerts are issued whenever there are elevated concentrations of ozone in the lower atmosphere. Nitmgen oxide, another component of photochemical smog, is a colorless gas produced in a side reaction in automobile engines. One reaction that links these species is the reaction of NO and O3 to produce O2 and NO2 ... 

In homogeneous catalysis, both the catalyst and the reactants are in the same phase, i.e. all are molecules in the gas phase, or, more commonly, in the liquid phase. One of the simplest examples is found in atmospheric chemistry. Ozone in the atmosphere decomposes, among other routes, via a reaction with chlorine atoms ... 

The reaction of volatile chlorinated hydrocarbons with hydroxyl radicals is temperature dependent and thus varies with the seasons, although such variation in the atmospheric concentration of trichloroethylene may be minimal because of its brief residence time (EPA 1985c). The degradation products of this reaction include phosgene, dichloroacetyl chloride, and formyl chloride (Atkinson 1985 Gay et al. 1976 Kirchner et al. 1990). Reaction of trichloroethylene with ozone in the atmosphere is too slow to be an effective agent in trichloroethylene removal (Atkinson and Carter 1984). 

Biomarker A molecule such as ozone in the atmosphere of a planet that might suggest the presence of life. 

Hexachloroethane is quite stable in air. It is not expected to react with hydroxyl radicals or ozone in the atmosphere or to photodegrade in the troposphere (Callahan et al. 1979 Howard 1989). Degradation by photolysis may occur in the stratosphere. 

Less than 1 pphm (parts per hundred million) of ozone in the atmosphere can severely attack non-resistant rubbers. However, there is far less, if any, problem with plastics and tests are rarely made. If required, the methods standardised for rubbers in ISO 1431 [24] could be used, which involve exposure in a special cabinet with controlled levels of ozone. 

American Association of Textile Colorists and Chemists. Colorfastness to ozone in the atmosphere under low humidities. AATCC Test Method 109-1972, pp. ldO-141. In AATCC Technical Manual. Vol. 49. Research Triangle Park, N.C. Ametkan Association of Textile Colorists and Chemists, 1973. 

American National Standards Institute (ANSI) Test Method for Colorfastness to Ozone in the Atmosphere under Low Humidities. L14, 174-1973. (same as AATCC Test Method 109-1972)... 

Photolytic. Based on data for structurally similar compounds, acenaphthylene may undergo photolysis to yield quinones (U.S. EPA, 1985). In a toluene solution, irradiation of acenaphthylene at various temperatures and concentrations all resulted in the formation of dimers. In water, ozonation products included 1,8-naphthalene dialdehyde, 1,8-naphthalene anhydride, 1,2-epoxyacenaphthylene, and 1-naphthoic acid. In methanol, ozonation products included 1,8-naphthalene dialdehyde, 1,8-naphthalene anhydride, methyl 8-formyl-1-naphthoate, and dimethoxyacetal 1,8-naphthalene dialdehyde (Chen et al., 1979). Acenaphthylene reacts with photochemically produced OH radicals and ozone in the atmosphere. The rate constants and corresponding half-life for the vapor-phase reaction of acenaphthylene with OH radicals (500,000/cm ) at 25 °C are 8.44 x lO " cmVmolecule-sec and 5 h, respectively. The rate constants and corresponding half-life for the vapor-phase reaction of acenaphthylene with ozone at 25 °C are... 

Photolytic. The following rate constants were reported for the reaction of 1,3-butadiene and OH radicals in the atmosphere 6.9 x 10 " cmVmolecule-sec (Atkinson et al., 1979) and 6.7 x lO " cmVmolecule-sec (Sabljic and Glisten, 1990). Atkinson and Carter (1984) reported a rate constant of 6.7-8.4 X 10 " cmVmolecule-sec for the reaction of 1,3-butadiene and ozone in the atmosphere. Photooxidation reaction rate constants of 2.13 x 10 and 7.50 x 10cm /molecule-sec were reported for the reaction of 1,3-butadiene and NO3 (Renter and Schindler, 1988 Sabljic and Glisten, 1990). The half-life in air for the reaction of 1,3-butadiene and NO3 radicals is 15 h (Atkinson et al., 1984a). 

The following rate constants were reported for the reaction of rafl5-l,2-dichloroethylene and ozone in the atmosphere 1.8 x lO cmVmolecule-sec at 298 K (Atkinson and Carter, 1984) and... 

Photolytic. Dimethylnitramine, nitrous acid, formaldehyde, V.V-dimethylformamide and carbon monoxide were reported as photooxidation products of dimethylamine with NOx. An additional compound was tentatively identified as tetramethylhydrazine (Tuazon et al., 1978). In the atmosphere, dimethylamine reacts with OH radicals forming formaldehyde and/or amides (Atkinson et al, 1978). The rate constant for the reaction of dimethylamine and ozone in the atmosphere is 2.61 x 10 cmVmolecule-sec at 296 K (Atkinson and Carter, 1984). 

Photolytic. The reported reaction rate constants for the reaction of 2-methyTl-pentene with OH radicals and ozone in the atmosphere are 1.05 x lO and 6.26 x 10 " cmVmolecule-sec, respectively (Atkinson and Carter, 1984 Atkinson, 1985). 

When CFCs slowly rise in the atmosphere and reach the ozone layer, they are broken down into component molecular compounds and atoms by the UV rays of the sun. Some of these chemicals then react with ozone to break it down, thus reducing the amount of O3. Further, some chlorine (also from the oceans) and some other elements combine with the O and to form other chemicals. This also contributes to the reduction of ozone faster than natural processes can reform it. Ozone is a renewable resource. The issue is this can a balance be obtained between the destruction of ozone in the atmosphere, by both natural and man-made causes, and its natural regeneration ... 

Ozone in the atmosphere is a good example of photochemical reactions. Atmospheric ozone is not due to equilibrium. The production and decomposition of ozone are largely by photochemical process, and the concentration of ozone in the stratosphere is at steady state, controlled by the kinetics of photochemical production and decomposition. 

The maximum concentration of ozone in the stratosphere (or the ozone layer) is about 9 ppm at an altitude of about 35 km. That is, the concentration of ozone in the so-called ozone layer is still very low. Transport of ozone in the atmosphere modifies ozone concentration levels at each altitude and latitude. It is emphasized that the steady-state concentration of O3 in the stratosphere is not the thermodynamic equilibrium concentration, but is established by kinetics of photochemical reactions. 

McKeen, S., D. Kley, and A. Volz, The Historical Trend of Tropospheric Ozone over Western Europe A Model Perspective, in Ozone in the Atmosphere (R. D. Bojkov and P. Fabian, Eds.),... 

In connection with the study of the role Freon compounds play in the depletion of ozone in the atmosphere, a demand has arisen for 13C-labeled fluorinated hydrocarbons in infrared spectroscopic examination. For this purpose,13C-isotopically enriched trichlorofluoromethane, dichlorodifluoromethane, chlorotrifluoromethane, trifluoromethane, chlorodifluoromethane, and dichlorofluoromethane have been prepared from 13CC 4 and 13CHC13.73... 

Onsager inverted snowball theory (Com.) relation to Smoluchowski equation in, 35 relaxation time by, 34 rotational diffusion and, 36 Ozone in the atmosphere, 108 alkene reactions with, 108 Crigee intermediate from, 108 molozonide from, 108 ethylene reaction with, 109 acetaldehyde effect on, 113 formic anhydride from, 110 sulfur dioxide effect on, 113 sulfuric acid aerosols from, 114 infrared detection of, 108 tetramethylethylene (TME) reaction with, 117... 

The numerical technique for the determination of vertical profile information was also studied for the determination of total ozone in the atmosphere by NASA (Dave and Mateer, 1967 Mateer et al., 1971). The development of this retrieval technique has continued up to the present (Bhartia et al., 1996). 

Historically, the photochemistry of oxygen and ozone has been of considerable interest because of the importance of oxygen and ozone in the atmosphere. In 1881 Hartley (39) postulated that ozone was a normal constituent of the upper atmosphere and that absorption of solar radiation by ozone could account for the limitation of the solar spectrum at about 3000 A. These speculations were not definitely corroborated until 1913 by Fabry and Buisson (26). The formation of ozone from oxygen in ultraviolet light in the region 1400-1900 A. was first reported by Lenard (53) in 1900 and afterwards confirmed by Goldstein (34) in 1903. 

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