Product in air

Raes, F., Janssens, A. and Vanmarcke, H., A closer look at the behaviour of radioactive decay products in air, The Science of the Total Env. 45 s 205 (1985b)... 

The most commonly used methods for measuring chlordecone and its degradation products in air, water, soil, sediment, fish, shellfish, and animal fat are similar to those used for mirex (i.e., GC/ECD techniques and confirmation by GC/MS). Because of the polar nature of chlordecone, the removal of... 

Photolytic. A photooxidation rate constant of 6 x 10 " cm /molecule-sec at room temperature was reported for the vapor-phase reaction of benzene with OH radicals in air (Atkinson, 1985). The reported rate constant and half-life for the reaction of benzene and OH radicals in the atmosphere are 8.2 x 10 M/sec and 6.8 d, respectively (Mill, 1982). Major photooxidation products in air include nitrobenzene, nitrophenol, phenol, glyoxal, butanedial, formaldehyde, carbon dioxide, and carbon monoxide (Nojima et al., 1975 Finlayson-Pitts and Pitts, 1986). 

Zinc oxide is obtained as an intermediate in recovering zinc from minerals (See Zinc, Recovery). The oxide is prepared by vaporizing zinc metal and oxidation of the zinc vapors with preheated air (French process). The oxide can be produced by other processes. Another method involves roasting franklinite and other ores with coal and then oxidizing the product in air. 

A number of pesticides are listed as HAPs (see Table 16.16). These can be transported significant distances from their point of application, and during that time they undergo chemical transformations as well as deposition (Kurtz, 1990). Table 16.17 shows some pesticides and their transformation products in air (Seiber and Woodrow, 1995). 

There are also methods for the analysis of diazinon degradation products in air, water, and soil. Williams et al. (1987) published a method for diazinon and its oxon (diazoxon) in air. Other methods have been reported for diazinon, its oxon, and hydrolysis products in water (Suffet et al. 1967), soils and water (Lichenstein et al. 1968), and soil (Burkhard and Guth 1979). The hydrolysis product 2-isopropyl-6-methyl-4-hydroxypyrimidine was studied along with diazoxon in submerged soil (Sethunathan and Yoshida 1969). Suffet et al. (1967) demonstrated the ability of GC to separate diazinon, diazoxon, and 2-isopropyl-6-methyl-4-hydroxypyrimidine. However, no validated methods for the determination of... 

The University of Nevada, Range Wildlife and Forestry, Reno, is developing and evaluating methods for determining diazinon and conversion products in air and atmospheric moisture. 

Attachment of decay products to nuclei greatly affects the process of deposition, because the Brownian diffusivity of nuclei is typically about four orders of magnitude less than the molecular diffusivity of unattached decay products. The lifetime of decay products in air before deposition on surfaces is shorter if the air is clean than if it is dirty. 

Formic esters are produced as the thermal degradation products in air... 

Seiber, J.N. Woodrow, J.E. Shafik, T.M. Enos, H.F. Determination of pesticides and their transformation products in air. In "Environmental Dynamics of Pesticides."... 

Density is also measured in terms of the specific gravity and the weight of a litre of product in air. The latter is a property of importance in international trade in fats and oils (Firestone, 1998). 

The ozone then becomes involved in a whole series of reactions with hydrocarbons in the atmosphere to form aldehydes, various free radicals, and other intermediates, which react further to produce undesirable products in air poilution ... 

Atmospheric concentrations are relatively high compared with other environmental compartments because of vinylidene chloride s high vapor pressure and low water solubility. The half-life for the chemical in air has been estimated to be 16 h and 2-3 days. Atmospheric hydroxyl radicals play a major role in its degradation. The major reaction products in air are formaldehyde, phosgene, and hydroxylacetyl chloride. 

Figure 12-4 shows a psychrometric chart for combustion products in air. The thermodynamic properties of moist air are given in Table 12-1. Figure 12-4 shows a number of useful additional relationships, e.g., specific volume and latent heat variation with temperature. Accurate figures should always be obtained from physical properties tables or by calculation using the formulas given earlier, and these charts should only be used as a quick check for verification. 

Negligible photoreaction was observed for p,p -dichlorobenzophenone (DCB), a DDT oxidation product, in air-saturated, distilled water (half-fife >15 h at 313 nm). Nevertheless, this halocarbon photoreacted (313 nm) with half-lives corrected for light attenuation of about 3 h in a filtered natural-water sample and a solution of Contech fulvic acid (Table II). The greater than four- to fivefold enhancement in photoreaction rate in this case probably results from hydrogen atom abstraction from the natural organic matter by the DCB in its excited triplet state (eq 14). 

Among the simple catalysts that have been proposed oxides of zinc,09 cadmium, lead, bismuth, silicon, aluminum, titanium may be mentioned.5,0 Alkaline materials as sodium or calcium carbonates have also been claimed. The zinc oxide catalyst is prepared by spraying a solution of zinc nitrate, alone or with nitrates of other metals, on pumice and then heating the product in air. In practice the phthalic anhydride is simply steam dis-stilled into the reaction chamber and the products separated by fractional condensation or selective solution. 

The federal government has developed regulatory standards and guidelines to protect workers from the potential health effects of other coal tar products in air. OSHA has set a Permissible Exposure Limit (PEL) of 0.2 milligrams of coal tar pitch volatiles per cubic meter of air (0.2 mg/m3) in workroom air to protect workers during an 8-hour shift. 

The preparation of a borosilicate molecular sieve (termed by the authors "borozeosilite") at relatively low pH, in the neutral to acidic range, has been reported (25). A reaction mixture comprising a silica source, boric acid, tetrapropyl-ammonium bromide and an ammonium fluoride salt was digested hydrothermally at 170°C. Subsequent calcination of the product in air at 550°C was performed to remove organic template and to provide the hydrogen form of the molecular sieve. 

Children may be exposed to organic manganese compounds through a variety of routes. They may be exposed to MMT combustion products via inhalation of these products in air, or ingestion of them after deposition on the soil. Children may be exposed to maneb and mancozeb by eating fruits and vegetables that have residues of these pesticides on them... 

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