Polycyclic aromatics, ozonation

Finlayson-Pitts BJ, IN Pitts (1997) Tropospheric air pollution ozone, airborne toxics, polycyclic aromatic hydrocarbons, and particles. Science 276 1045-1052. 

Because process mixtures are complex, specialized detectors may substitute for separation efficiency. One specialized detector is the array amperometric detector, which allows selective detection of electrochemically active compounds.23 Electrochemical array detectors are discussed in greater detail in Chapter 5. Many pharmaceutical compounds are chiral, so a detector capable of determining optical purity would be extremely useful in monitoring synthetic reactions. A double-beam circular dichroism detector using a laser as the source was used for the selective detection of chiral cobalt compounds.24 The double-beam, single-source construction reduces the limitations of flicker noise. Chemiluminescence of an ozonized mixture was used as the principle for a sulfur-selective detector used to analyze pesticides, proteins, and blood thiols from rat plasma.25 Chemiluminescence using bis (2,4, 6-trichlorophenyl) oxalate was used for the selective detection of catalytically reduced nitrated polycyclic aromatic hydrocarbons from diesel exhaust.26... 

Bioventing technology was developed by the U.S. EPA Risk Reduction Engineering Laboratory to treat soil contaminated by numerous industrial wastes, which is subjected to aerobic microbial degradation, especially to promote the degradation of polycyclic aromatic hydrocarbons.65 It uses a series of air injection probes, each of which is attached to a low-pressure air pump. The air pump operates at extremely low pressures to allow the inflow of oxygen without volatilization of contaminants. Additional additives such as ozone or nutrients may also be supplied to stimulate microbial growth.77... 

Yoshikawa, T., L.P. Ruhr, W. Flory, D. Giamalva, D.F. Church, and W.A. Pryor. 1985. Toxicity of polycyclic aromatic hydrocarbons. I. Effect of phenanthrene, pyrene, and their ozonized products on blood chemistry in rats. Toxicol. Appl. Pharmacol. 79 218-226. 

For soybean-based biodiesel at this concentration, the estimated emission impacts for percent change in emissions of NO,, particular matter (PM), HC, and CO were +20%, -10.1%, -21.1%, and -11.0%, respectively (EPA, 2002). The use of blends of biodiesel and diesel oil are preferred in engines in order to avoid some problems related to the decrease of power and torque, and to the increase of NO, emissions (a contributing factor in the localized formation of smog and ozone) that occurs with an increase in the content of pure biodiesel in a blend. Emissions of all pollutants except NO appear to decrease when biodiesel is used. The use of biodiesel in a conventional diesel engine dramatically reduces the emissions of unbumed hydrocarbons, carbon dioxide, carbon monoxide, sulfates, polycyclic aromatic hydrocarbons, nitrated polycyclic aromatic hydrocarbons, ozone-forming hydrocarbons, and particulate matter. The net contribution of carbon dioxide from biomass combustion is small. 

When epidemiological studies form the basis for the risk assessment of a single chemical or even complex mixtures, such as various combustion emissions, it may be stated that in those cases the effects of combined action of chemicals have been incorporated. Examples can, for instance, be found in the updated WHO Air Quality guidelines (WHO 2000). Thus, the guideline value for, e.g., ozone was derived from epidemiological studies of persons exposed to ozone as part of the total mixture of chemicals in polluted ambient air. In addition, the risk estimate for exposure to polycyclic aromatic hydrocarbons was derived from studies on coke-oven workers heavily exposed to benzo[fl]pyrene as a component of a mixture of PAH and possibly many other chemicals at the workplace. Therefore, in some instances the derivation of a tolerable intake for a single compound can be based on studies where the compound was part of a complex chemical mixture. 

Finlayson-Pitts, B. J., and J. N. Pitts, Jr., Tropospheric Air Pollution Ozone, Airborne Toxics, Polycyclic Aromatic Hydrocarbons, and Particles, Science, 27b, 1045-1052 (1997). 

Alebic-Juretic, A., T. Cvita, and L. Klasinc, Heterogeneous Polycyclic Aromatic Hydrocarbon Degradation with Ozone on Silica Gel Carrier, Environ. Sci. Technol., 24, 62-66(1990). 

Pitts, J. N., Jr., H.-R. Paur, B. Zielinska, J. Arey, A. M. Winer, T. Ramdahl, and V. Mejia, Factors Influencing the Reactivity of Polycyclic Aromatic Hydrocarbons Adsorbed on Filters and Ambient POM with Ozone, Chemosphere, 15, 675-685 (1986). 

Van Vaeck, L., and K. Van Cauwenberghe, Conversion of Polycyclic Aromatic Hydrocarbons on Diesel Particulate Matter upon Exposure to PPM Levels of Ozone, Atmos. Environ., 18, 323-328... 

Wu, C.-H., I. Salmeen, and H. Niki, Fluorescence Spectroscopic Study of Reactions between Gaseous Ozone and Surface-Adsorbed Polycyclic Aromatic Hydrocarbons, Environ. Sci. Tech-noL, 18, 603-607 (1984). 

Kornmiiller A, Cuno M, Wiesmann U (1996) Ozonation of oil/water-emulsions containing polycyclic aromatic hydrocarbons. International Conference Analysis and utilisation of oily wastes , AUZO 96, Proceedings, Vol. I, Technical University of Gdansk, Poland. 

Kommiiller A, Cuno M, Wiesmann U (1997 a) Ozonation of polycyclic aromatic hydrocarbons in synthetic oil/water-emulsions, International Conference on Ozonation and related Oxidation Processes in Water and liquid Waste Treatment, International Ozone Association, European-African Group, Wasser Berlin 1997, April 21-2.7. 

KornmUller A, Wiesmann U (1999) Continuous ozonation of polycyclic aromatic hydrocarbons in oil/ water-emulsions and biodegradation of oxidation products, Water, Science Technology 40 107— 114. 

The reaction does not have preparative significance. However, it has been surmised that polycyclic aromatic hydrocarbons adsorbed on atmospheric particulate matter can become activated as a result of atmospheric oxidation. Samples of such materials could display a degree of mutagenicity not associated with inactivated hydrocarbons. Although in many cases the precise nature of the oxidant is not clear, Pitts et al.60 have been able to show that ozone can convert benzo[a] pyrene, adsorbed on a glass filter, to its 4,5-oxide (28). 

Trapido, M., Veressinina, Y., and Munter, R., Ozonation and advanced oxidation processes of polycyclic aromatic hydrocarbons in aqueous solutions a kinetic study, Environ. Technol., 16, 729-740, 1995. 

Oxidizer Chemical substance that causes oxygen to combine with another chemical substance examples include oxygen and hydrogen peroxide Ozone depletion Destruction of the stratospheric ozone layer that protects the Earth from harmful effects of ultraviolet radiation. Depletion of ozone layer is due to the breakdown of certain chlorine- and/or bromine-containing compounds (chlorofluorocarbons or halons), which break down when they reach the stratosphere and then catalytically destroy ozone molecules Ozone layer Protective layer in the atmosphere, about 15 miles above the ground. The ozone layer absorbs some of the sun s ultraviolet rays, thereby reducing the amount of potentially harmful radiation that reaches the Earth s surface PAHs Polycyclic aromatic hydrocarbons... 

Sulfur dioxide, carbon dioxide, nitric oxide, heat, acids, acid rain, ozone, soot, polycyclic aromatic hydrocarbons, and volatile organic compounds Pesticides, nitrates, phosphates, greenhouse gases, and mineral salts... 

Polycyclic aromatic hydrocarbons Benzo(a)pyrenes Methylcholanthrene Dimethylbenz(a)anthracene Solvents Benzene Heavy metals Beryllium Manganese Nickel Cadmium Platinum Air pollutants Ozone... 

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