Ozonation INDEX

The full text of the 1985 Vienna Convention for the Protection of the Ozone Layer is available at http //www.unep.org/ozone/vienna t.shtml, and contains much of the primary data that alerted the scientific community to the threats of CFCs, etc. It is somewhat dated now, but the Web page of the United Nations Ozone Secretariat is more reliable http //www.unep.org/ozone/index-en.shtml. 

This site and hotline provides information about the science of ozone depletion, regulations under Title VI of the Clean Air Act Amendments (CAAA) of1990 designed to protect the ozone layer, information on methyl bromide, flyers about the UV index, information for the general public, and other topics. Hours 10 00 a.m. - 4 00p.m., weekdays, EST. 

The extent to which this occurs depends on a number of issues (Finlayson-Pitts and Pitts 1997), including the reactivity of the hydrocarbon that is itself a function of many factors. It has been proposed that the possibility of ozone formation is best described by a reactivity index of incremental hydrocarbon reactivity (Carter and Atkinson 1987, 1989) that combines the rate of formation of O3 with that of the reduction in the concentration of NO. The method has been applied, for example, to oxygenate additives to automobile fuel (Japar et al. 1991), while both anthropogenic compounds and naturally occurring hydrocarbons may be reactive. 

The carbonyl index obtained from transmission and ATR spectra of PP films UV-irradiated (L2) in ozone shows that the concentration of carbonyl groups at the surface is 8 times higher than in a bulk. 

The detailed model was constructed as described by Carslaw et al. (1999, 2002). Briefly, measurements of NMHCs, CO and CH4 were used to define a reactivity index with OH, in order to determine which NMHCs, along with CO and CH4, to include in the overall mechanism. The product of the concentration of each hydrocarbon (and CO) measured on each day during the campaign and its rate coefficient for the reaction with OH was calculated. All NMHCs that are responsible for at least 0.1% of the OH loss due to total hydrocarbons and CO on any day during the campaign are included in the mechanism (Table 2). Reactions of OH with the secondary species formed in the hydrocarbon oxidation processes, as well as oxidation by the nitrate radical (NO3) and ozone are also included in the... 

Toxicologic research (Chapter 8) on the effects of ozone in laboratory animals has demonstrated that exposure to airborne ozone at less than 1 ppm for a few hours produces numerous changes in cell and organ structure and function. The lowest concentrations that produce these changes differ somewhat among different species of laboratory animals and with the effect under observation. However, several functional and morphologic indexes of response to ozone are altered with exposures to concentrations of about 0.2-0.5 ppm over periods ranging from a few minutes to several weeks. 

As mentioned previously, decreased voluntary running activity of mice was one of the most sensitive indexes of an effect of ambient photochemical oxidant air pollution or simulated oxidant smog that was produced in the laboratory by irradiating diluted auto-exhaust gases. Whether this effect of the mixtures was due only to ozone or to some other oxidant is not certain. It is plausible to conclude that ozone was the... 

It was concluded that malonaldehyde (an index of lipid peroxidation) was formed only in the later stages of ozone damage. Frederick and Heath reported that the production of malonaldehyde is correlated... 

Studies of the reaction of ozone with simplified lipid systems have shown that malonaldehyde can be produced by direct ozonolysis. The use of malonaldehyde assay as an index of lipid peroxidation is therefore invalid in ozone studies. Liposomes formed from egg lecithin and prepared in aqueous media were quite resistant to ozone, but the contribution of polyconcentric spheres to this resistance has not been fully assessed. However, the bilayer configuration, with the susceptible unsaturated fatty acids shielded from ozone by the hydrophilic areas of the molecule, may be resistant. In hexane, where the fatty acid moieties are exposed, ozone reacts stoichiometrically with the double bonds. The experiments with aqueous suspensions of phosphatidylcholine gave no evidence of the formation of lipid peroxides,nor did experiments with films of fatty acids exposed to ozone. ... 

Acroldn concentration, 186,187 Adenosine triphosphate, effect of ozone on lung concentration of, 354 Aerosol carbon balance, 50 Aerosol formation, 4, 14, 674-76 ability index, 61 diemical medianisms of, 72 hydrox]4 radical-aromatic hydrocar> bon reaction, 76-81 ozone-olefin reaction, 72-76 condensable species vapor pressure and, 86-90,101... 

Table I. Index of ozone injury to foliage of 12 peanut cultivars and total plant phenol expresses "a % caffeic acid equivalents in assay...

Pale blue gas (in undiluted form) irritating odor above a concentration of 0.15 ppm, but the odor may be pleasant and refreshing at about 0.05 ppm density of gas 2.144g/L at 0°C liquefies at -111.9°C to a dark blue liquid density of liquid ozone 1.614 g/L at -195.4°C refractive index of liquid 1.2226 freezes at -192.7° C to a bluish-black solid critical temperature -12.05°C critical pressure 54.98 atm critical volume 89cm3/mol sbghtly soluble in water. 

NO, Peak 50-100% increase for an index of 5 g of N02/kg of Ozone depletion by NO, catalysis at higher altitudes fuel interference with CIO, HO, and BrO, catalysis at lower altitudes... 

Analogous approaches to assessing VOC reactivities have been developed by Derwent and co-workers (e.g., see Hough and Derwent, 1987 Derwent and Jenkin, 1991 and Derwent et al., 1996) where a trajectory model is used to calculate the additional ozone production due to the addition of a particular VOC under conditions typical of air masses advected across northwest Europe toward the British Isles. The photochemical ozone creation potential (POCP) index thus calculated is a measure of the reactivity of the particular VOC in terms of 03 formation. Andersson-Skold and co-workers (1992) followed a similar approach for the summer conditions in southern Sweden. 

The copolymer of isobutylene with a few percent isoprenc (butyl rubber) can be cured to produce an ozone-resistant elastomer with low permeability to oxygen and nitrogen. Butyl rubber has a Tt of — 70 C a refractive index of 1.5081, and a coefficient of linear expansion of 5.7 X 10 cm/cxn C. Chloro and bromo butyl rubber are more resistant to the permeation of oxygen and nitrogen than butyl rubber. 

Fig. 2. Observed correlations between the photolysis frequency of ozone and total ozone (upper panel) and the photolysis frequency of NO, and the TOMS index of aerosol load (lower panel) during PAURII (May 1999).

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