Sulfur dioxide data

The urban RAM model was evaluated (52) using 1976 sulfur dioxide data from 13 monitoring locations in St. Louis on the basis of their second-highest once-a-year concentrations. The ratio of estimated to measured 3-h average concentrations was from 0.28 to 2.07, with a median of 0.74. Half of the values were between 0.61 and 1.11. For the 24-h average concentrations the ratios ranged from 0.18 to 2.31, with a median of 0.70. Half of the values were between 0.66 and 1.21. Thus, the urban RAM model generally underestimates concentrations by about 25%. 

A. Slack and G. HoUinden, Sulfur Dioxide Removalfrom Waste Gases, 2nd ed., Noyes Data Corp., Park Ridge, N.J., 1975, pp. 227—238. 

Health, Safety, and Environmental Factors. Sulfur dioxide has only a moderate acute toxicity (183). The lowest pubHshed human lethal concentration is 1000 ppm for 10 months. The lowest pubHshed human toxic concentration by inhalation is 3 ppm for 5 days or 12 ppm for 1 hour. The lowest pubHshed human lethal concentration is 3000 ppm for 5 months. In solution (as sulfurous acid), the lowest pubHshed toxic dose is 500 flg/kg causing gastrointestinal disturbances. Considerable data is available by other modes of exposure and to other species NIOSH standards are a time-weighted average of 2 ppm and a short-term exposure limit of 5 ppm (183). 

The thermodynamic properties of sulfur trioxide, and of the oxidation reaction of sulfur dioxide are summarized in Tables 3 and 4, respectively. Thermodynamic data from Reference 49 are beheved to be more accurate than those of Reference 48 at temperatures below about 435°C. 

The index of refraction of sulfuric acid solutions (62) and additional related data (66), along with solubiUty data for oxygen in sulfuric acid solutions (67), are available in the Hterature. The solubiUty of sulfur dioxide in concentrated sulfuric acid is shown in Figure 9 (68) additional data are also available (69). 

The density of oleum at 20°C (76) and at 25°C (39) has been reported. The boiling points of oleum are presented in Figure 15 (86). Freezing points are shown in Figure 16 (75,87). An excellent discussion on the crystallisation points of oleum is available (69). The solubiUty of sulfur dioxide in oleum has been reported (68,69). Viscosity of oleum is summarized in Figure 17 (55) additional viscosity data are available (76). 

Hot surfaces and electric sparks are potential ignition sources for carbon disulfide. The ignition temperature depends on specific conditions, and values from 90 to 120°C in air have been reported (2,22). Data on carbon disulfide oxidation and combustion have been summarized (18). Oxidation products ate generally sulfur dioxide [7446-09-5] and carbon dioxide [124-58-9J ... 

Flame Temperature. The adiabatic flame temperature, or theoretical flame temperature, is the maximum temperature attained by the products when the reaction goes to completion and the heat fiberated during the reaction is used to raise the temperature of the products. Flame temperatures, as a function of the equivalence ratio, are usually calculated from thermodynamic data when a fuel is burned adiabaticaHy with air. To calculate the adiabatic flame temperature (AFT) without dissociation, for lean to stoichiometric mixtures, complete combustion is assumed. This implies that the products of combustion contain only carbon dioxide, water, nitrogen, oxygen, and sulfur dioxide. 

Fig. 4-8. Sulfur dioxide concentration versus averaging time and frequency for 1980 at U S. National Aerometric Data Bank (NADB) Site 264280007 HOI, 8227 S. Broadway, St. Loutis, Missouri. Source Chart courtesy of Dr. Ralph Larsen, U.S. Environmental Protection Agency, Research Triangle Park, NC see also Fig. 19-13.

For sources having a large component of emissions from low-level sources, the simple Gifford-Hanna model given previously as Eq. (20-19), X = Cqju, works well, especially for long-term concentrations, such as annual ones. Using the derived coefficients of 225 for particulate matter and 50 for SO2, an analysis of residuals (measured minus estimated) of the dependent data sets (those used to determine the values of the coefficient C) of 29 cities for particulate matter and 20 cities for SOj and an independent data set of 15 cities for particulate matter is summarized in Table 20-1. For the dependent data sets, overestimates result. The standard deviations of the residuals and the mean absolute errors are about equal for particulates and sulfur dioxide. For the independent data set the mean residual shows... 

For any pollutant, air quality criteria may refer to different types of effects. For example. Tables 22-1 through 22-6 list effects on humans, animals, vegetation, materials, and the atmosphere caused by various exposures to sulfur dioxide, particulate matter, nitrogen dioxide, carbon monoxide, ozone, and lead. These data are from fhe Air Quality Criteria for these pollutants published by the U.S. Environmental Protection Agency. 

Fire Hazards-Fto/iPomr (deg. F) 53 OC Flammable Limits in Air (%) No data Fire Extinguishing Agents Dry chemical, alcohol foam, carbon dioxide Fire Extinguishing Agents Not To Be Used Water Special Hazards of Combustion Products Irritating sulfur dioxide Behavior in Fire Vapors... 

N. 1. Sa., ed.. Sulfur Dioxide, Dangerous Properties of Industrial Materials Report, Vol. 1, No. 3, Januaiy -February, New York, 1981. Material Safety Data Sheet, Liquid Air Corporation, Alphagaz Division, Walnut Creek, CA, October 1985. 

From a practical point of view, literature data indicate that it is not necessary in most cases to isolate the title salts prior to their reaction. Tliis can be readily understood since their preparation is nearly quantitative and sulfur dioxide is the sole product evolved during their formation. In fact, it is highly advisable to recourse to a two-step procedure during the reactions between A -(l-chloroalkyl)pyridinium chlorides and amino acids (Section IV,C,6) (97BSB383). 

Sulfur dioxide hydrate, thermodynamic data and lattice constants, 8 Sulfur hexafluoride (SFa), hydrate, 22, 47... 

There is no clear reason to prefer either of these mechanisms, since stereochemical and kinetic data are lacking. Solvent effects also give no suggestion about the problem. It is possible that the carbon-carbon bond is weakened by an increasing number of phenyl substituents, resulting in more carbon-carbon bond cleavage products, as is indeed found experimentally. All these reductive reactions of thiirane dioxides with metal hydrides are accompanied by the formation of the corresponding alkenes via the usual elimination of sulfur dioxide. 

Four IR absorption bands have been identified in the spectrum of the hydroxysulfonyl radical (HOSO 2) which has been obtained by the reaction of hydroxyl radicals with sulfur dioxide in argon matrix at 11 K16. The observed bands at 3539.9 and 759.5 cm 1 have been assigned to O—H and S—OH stretching modes while the bands at 1309.2 and 1097.3 cm-1 have been assigned to the asymmetric and symmetric stretching modes of the double bonded S02 moiety. These data are consistent with the theoretical prediction on the geometry of the hydroxysulfonyl radical12. 

When lcad(II) sulfide is treated with hydrogen peroxide, the possible products are either lead(II) sulfate or lead(IV) oxide and sulfur dioxide, (a) Write balanced equations for the two reactions, (b) Using data available in Appendix 2A, determine which possibility is more likely. 

The network is implemented by the participating countries through WHO. Sulfur Dioxide (SO,) and suspended particulate matter (SPN) data are routinely reported from each of the participating countries to WHO for entry into the global data base, which is maintained by the United States Environmental Protection Agency (U.S. EPA) at Research Triangle Park, North Carolina. Methods of collection and analysis varies by country. SPN is reported either as a gravimetric or a photometric (transmittance or reflectance) measurement converted to mass units. Since the accuracy of the conversion of the photometric measurement to mass units is... 

The sulfur dioxide enters the reactor with an initial concentration of 10% by volume, the remainder being air. At the exit of the first bed, the temperature is 620°C. Assume ideal gas behavior, the reactor operates at 1 bar and R = 8.3145 kJ-Kr -lonoD1. Assume air to be 21% 02 and 79% N2. Thermodynamic data at standard conditions at 298.15 K are given in Table 6.186. 

Hint 1. Although sulfur dioxide and oxygen do not appear to be present in equimolar amounts for several of the data points, you may assume, as Mathur and Thodos did, that they are close enough for the purposes of this qualitative analysis. 

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