Ozonation factors affecting

For reliable calibrations, it was necessary to develop a stable and reproducible ozone source that could produce ozone in air at concentrations smaller than parts per million. After this was accomplished, several different versions were engineered they are now available commercially from vendors of most ozone-monitoring instruments. The factors affecting the production and survival of oxygen species other than ozone are discussed in Chapter 12. Care must be taken to prevent these species from creating interference when ozone is generated for instrument calibration. 

Kagawa and Toyama in Tokyo followed 20 normal 11-yr-old school children once a week from June to December 1972 with a battery of pulmonary-function tests. Environmental factors studied included oxidant, ozone, hydrocarbon, nitric oxide, nitrogen dioxide, sulfur dioxide, particles, temperature, and relative humidity. Temperature was found to be the most important environmental factor affecting respiratory tests. The observers noted that pulmonary-function tests of the upper airway were more susceptible to increased temperature than those of the lower airway. Although the effect of temperature was the most marked, ozone concentration was significantly associated with airway resistance and specific airway conductance. Increased ozone concentrations usually occur at the same time as increased temperature, so their relative contributions could not be determined. 

Ting, I. P., and W. M. Dugger, Jr. Factors affecting ozone sensitivity and susceptibility of cotton plants. J. Air Pollut. Control Assoc. 18 810-813, 19M. 

The effect of ozone injury on herbaceous plant reproduction has been mentioned earlier in this chapter and in Chapter 11. Seed production by annuals is influenced mainly by the envirorunental conditions of the current year, but perennial woody plants—particularly conifers—are erratic seed-producers. Intrinsic factors affecting cone production include age and vigor seasonal temperature and soil moisture are important environmental factors. ... 

Shiotani, M., and J. C. Gille, Dynamical Factors Affecting Ozone Mixing Ratios in the Antarctic Lower Stratosphere, J. Geophys. Res., 92, 9811-9824 (1987). 

Abdul-Wahab, S.A., Bakheit, C.S. and Al-Alawi, S.M., 2005. Piincip)al component and multiple regression analysis in modeling of ground-level ozone and factors affecting its concentrations. Environmental Modelling Software 20, p.1263-1271. 

In addition, there is the Biophysical Monitoring Program for Climatic Change operated by the National Oceanographic and Aerometric Administration of the U.S. Department of Commerce. This data base collects data on carbon dioxide, ozone, aerosols, precipitation, solar radiation, and fluorocarbon levels at stations located worldwide. This is an attempt to measure long-term trends in factors affecting climatic change. 

Neely W. (1984). Factors affecting the pretrealment of biomass with gaseous ozone. Biotechnol Bioeng, 26, 59-65. 

Egitto, F. D. Matienzo, L. J., Transformation of Polyfdimethylsiloxane) into Thin Surface Films of SiO by UV/Ozone Treatment. Part I Factors Affecting Modification. J. Mater. Sci. 2006, 41, 6362-6373. 

The rate of aqueous ozonation reactions is affected by various factors such as the pH, temperature, and concentration of ozone, substrate, and radical scavengers. Kinetic measurements have been carried out in dilute aqueous solution on a large number of organic compounds from different classes (56,57). Some of the chemistry discussed in the foUowing sections occurs more readily at high ozone and high substrate concentrations. 

Ozone is only slightly soluble in water. Thus, factors that affect the mass transfer between the gas and Hquid phases are important and include temperature, pressure, contact time, contact surface area (bubble size), and pH. 

With rubber base adhesives, it is necessary to prevent their properties from changing during service life. Oxidative changes induced by thermal, ozone exposure and UV light can dramatically affect service life of rubber base adhesives. More precisely, the rubber and the resin are quite susceptible to oxidative degradation. Environmental and physical factors exert detrimental effects on rubber base adhesive performance. These effects can be mitigated by the incorporation of low levels of stabilizers during the fabrication process of the adhesive. 

It is clear that human action can affect seven of eight of the major gi eenhouse forcings carbon dioxide, methane, nitrous oxide, ozone, CFCs, aerosols, and water vapor. As studies of solar variation have shown, it is also clear that human action is not the only factor involved in determining the impact of these forcings. There is still substantial uncertainty regarding the actual climate impact of the climate forcings. 

Effect of UV on Productivity of the Southern Ocean. Has ozone depletion over Antarctica affected the productivity of the Southern Ocean There is no easy answer. First, one has to take into account the fact that the drastic decrease of ozone over Antarctica has been reported as recently as 1976, a relatively short time in the evolution of the organisms to develop mechanisms to cope with elevated UV. One of the most vexing problems in studying the effects of UV radiation on productivity, is a dearth of historical data on the level of UV. Without these baselines, normal fluctuations could easily be interpreted as decline in productivity. Second, there is a host of biotic and abiotic factors that play significant roles in governing the productivity of the Southern Ocean (40). Ultraviolet radiation is but one more complicating factor to be considered in an already stressful environment. 

Physiologic Effects Leaf age and illumination have been studied as physiologic and physical factors that affect the response of plants to PAN. Leaves of most plants are most susceptible when very young. In primary leaves of pinto bean, the period of maximal susceptibility to PAN precedes that for ozone by several days (about 5-7 days from seed for PAN, as opposed to 9-13 days for ozone). The example of tomato is particularly striking, inasmuch as the terminal leaflet of the compound leaf is the oldest tissue. Thus, the youngest susceptible leaf is affected in the terminal leaflet but, as the leaves become older, the terminal leaflet is resistant and the lateral leaflets are injured. ... 

Only metabolites leached from the cell were affected. Elford and van den Ende reported that ozone at 20 ppm had a lethal effect on some bacteria deposited from aerosol mists on various surfaces. Relative humidity is an important factor, particularly when ozone concentration is low. They found little death at a humidity below 45%, at concentrations of 1 ppm, as opposed to a 90% kill in 30 min at 0.025 ppm with a humidity of around 70%. A 5-min exposure of Bacillus cereus to ozone at 0.12 mg/liter was the minimal lethal dose, whereas 0.10 mg/liter was effective for B. megaterium and E. coli. Spores of the Bacillus sp. were killed by ozone at 2.29 mg/liter. These responses were of the all-or-none type with ozone between 0.4 and 0.5 mg/liter of water. Time of exposure, from 1 to 32 min, was not important. Chlorine was effective at 0.27-0.30 mg/liter, with time an important consideration. These two gases did not affect E. coli in the same way. 

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