Pollution ozone

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

Halogenated hydrocarbon liver injury FFA-induced pancreatitisf Air pollutants (ozone, SO2, NOa)... 

In many risk analyses standard dispersion models, available from the EPA for regulatory compliance purposes, are used to compute concentration patterns for prototypes of a class of sources, and the patterns are convolved with population patterns that are characteristic of the source sites (5, 6). A similar level of analysis detail that relies on measured pollutant (ozone) concentration in each county of the Northeast Corridor rather than on modeled concentrations was used by Johnson and Capel ( 7). 

Many wastewater flows in industry can not be treated by standard aerobic or anaerobic treatment methods due to the presence of relatively low concentration of toxic pollutants. Ozone can be used as a pretreatment step for the selective oxidation of these toxic pollutants. Due to the high costs of ozone it is important to minimise the loss of ozone due to reaction of ozone with non-toxic easily biodegradable compounds, ozone decay and discharge of ozone with the effluent from the ozone reactor. By means of a mathematical model, set up for a plug flow reactor and a continuos flow stirred tank reactor, it is possible to calculate more quantitatively the efficiency of the ozone use, independent of reaction kinetics, mass transfer rates of ozone and reactor type. The model predicts that the oxidation process is most efficiently realised by application of a plug flow reactor instead of a continuous flow stirred tank reactor. 

Fairchild, E. J., S. D. Murphy, and H. E. Stokinger. Protection by sulfur com pounds against the air pollutants ozone and nitrogen dioxide. Science 130 861-862 1959. 

Heggestad, H. E., and H. A. Menser. Leaf spot-sensitive tobacco strain Bel W-3, a biological indicator of the air pollutant ozone. Phytopathology 52 735, 1%2. 

In recent years there has been increased interest in elucidating the biochemical and physiological responses of plants to air pollutants. Ozone has received particular scrutiny because of its importance in photochemical smog. The effects of ozone on the spectrum of physiological and biochemical systems has been analyzed in plant systems both vivo and vitro to... 

The effects of the secondary air pollutant, ozone, on growing plant systems have been extensively documented phenomenologically, There are at least three proposed mechanisms by which ozone could cause injury, each of which must operate within a framework of temporal sensitivity determined by the state of differentiation of the plant (11),... 

In this section, we use another chain reaction to show the relation between the steady-state treatment and the quasi-equilibrium treatment. The former is more general than the latter, and leads to more complete but also more complicated results. Ozone, O3, is present in the stratosphere as the ozone layer, and in the troposphere as a pollutant. Ozone production and destruction in the atmosphere is primarily controlled by photochemical reactions, which are discussed in a later section. Ozone may also be thermally decomposed into oxygen, O, although... 

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). 

Criteria pollutants six common pollutants—ozone (O3), carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), lead (Pb), and particulate matter less than 10 microns (10 pm) in size—regulated since 1970 in the United States and presenting relatively well quantified risks... 

Ozone. 03 is the principal oxidizing component in photochemically produced air pollutants. Ozone probably causes more injury to vegetation than any other pollutant in the United States (6). Phytotoxic levels frequently occur near industrial complexes and densely populated urban areas. Exposure for two or more hours to concentrations of 10 parts per hundred million (pphm) of air may cause acute injury to several of the most sensitive species of plants. 

Textile dyes Air pollutants, ozone, and NO2 cause deterioration, reduced strength, and fading... 

Due to the contrasting diurnal patterns of primary and secondary pollutants, ozone and other secondary pollutants appear to anticorrelate with their precursor species (NO and VOCs) if measured concentrations are plotted for a full diurnal cycle. Peak ozone occurs during and after the time of maximum sunlight, which is also the time of maximum vertical dilution. Concentrations of primary pollutants reach their diurnal minimum at this time. 

Volatile organic compounds (VOC) are essentially considered the same as the criteria pollutant ozone (119). n-Hexane and hexane isomers are VOCs. Most U.S. cottonseed oil extracting facilities would be major sources of VOCs and would be covered by the requirements for ozone emissions and attainment, unless they used a solvent that was not classified as a VOC (e.g., acetone). 

Ozone does occur in fairly large amounts under special conditions. For example, there is an unusually large amount of ozone in Earth s upper atmosphere. That ozone layer is important to life on Earth. It shields out harmful radiation that comes from the sun. Ozone is also sometimes found closer to Earth s surface. It is produced when gasoline is burned in cars and tmcks. It is part of the condition known as air pollution. Ozone at ground level is not helpful to life, and may cause health problems for plants, humans, and other animals. 

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

Notice that the ADI is not a direct expression of risk. Risk, recall, is a probability the ADI is a very low risk intake, or dose, with very low undefined. If there were some means to estimate the fraction of the population having thresholds lower than the ADI (the potentially at risk group), then a measure of the risk associated with the ADI could be obtained. No means exist to do this except for a few agents, particularly those such as the common air pollutants (ozone, carbon monoxide, sulfur and nitrogen oxides) that cause readily observable damage to human health. 

The extreme sensitivity of phthalocyanine sensors to oxidants has raised the possibility that common urban pollutants ozone and NOx are responsible for much of the conductivity of phthalocyanine devices in ambient conditions [133]. Indeed, phthalocyanine OTFTs on prolonged exposure to ambient air often exhibit an increase in device current however, their FET characteristics are also degraded so that they no longer can be switched off [34]. High humidity can reverse the process and restore FET characteristics. The high sensitivity of phthalocyanine OTFTs to pollutants may limit sensing applications and improved stability in... 

Several challenges remain for the ultimate practical use of these sensors. The response time of the solid state sensors are short (seconds) for initial sensing, but recovery times range from minutes to hours at room temperature. The stability of the sensor to drift associated with accumulation of fixed charge at interfaces, as well as the high sensitivity to ubiquitous urban pollutants ozone and N02 are problematic. All MPc OTFTs show some response to moisture, and conductivity is also temperature sensitive so that humidity and temperature compensation are essential. On a basic research level, the detailed characterization of charge trapping states, electronic structure, and the interactions with analytes is not yet fully understood on a quantitative theoretical basis. The time response of sensor initiation and recovery is also not understood in a detailed manner. In spite of these limitations, the intrinsic chemical stability of MPc compounds and their compatibility with microsensor array fabrication make these candidate OTFTs for further research and development. 

Blank (1985) reports that there is only one data set which gives a clear idea of the trend in natural background ozone concentrations in Europe, over the past 20 years. On the Isle of Rugen (in the Baltic, off the German Democratic Republic) an area not affected by any local pollution, ozone levels increased by 60% between 1956 and 1977. A similar trend has been reported for two other stations in forest areas of East Germany. 

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