Sulfur dioxide concentrations

Sulfur dioxide concentrations as low as 40 mg/m in air have been determined bypassing air samples through an aqueous solution of tetrachloromercurate, which converts SO2 to the dichlorosulfitomercurate complex. Oxidation of the complex by potassium permanganate is chemiluminescent and the intensity, as measured by a photomultipHer, is proportional to sulfur dioxide concentration (312). 

Pan and cascade burners are generally more limited ia flexibiHty and are useful only where low sulfur dioxide concentrations are desired. Gases from sulfur burners also contain small amounts of sulfur trioxide, hence the moisture content of the air used can be important ia achieving a corrosion-free operation. Continuous operation at temperatures above the condensation poiat of the product gases is advisable where exposure to steel (qv) surfaces is iavolved. Pressure atomiziag-spray burners, which are particularly suitable when high capacities are needed, are offered by the designers of sulfuric acid plants. 

Sulfur dioxide concentrations in oleum ate rarely specified or measured, but typical values are considerably higher than in acids of <99 wt % concentrations. This occurs because oleum is produced at relatively low temperatures in the presence of appreciable SO2 in the gas phase, thus lea ding to high solubihty. It is not possible to strip SO2 from oleums by air blowing, a technique that is ftequentiy appHed to product acids of <99% concentration. 

In duidized-bed roasters (19), the concentrate is suspended in an upward-moving air stream. The vessel is a refractory-lined steel shell with air entering through holes in a refractory-lined plate at the base. The sulfur dioxide concentration of the exit gas is 10—15%. 

Fig. 4-4. Urban trends in annual sulfur dioxide concentrations. Source U.S. Environmental Protection Agency, 1992,...

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.

Fig. 9-1. Relationship between corrosion of mild steel and corresponding mean sulfur dioxide concentration at seven Chicago, Illinois sites. Source Upham, J. B., /. Air PoUut, Control Assoc. 17, 4(X) (1967).

From the commencement of the fog and low visibility, many people experienced difficulty breathing, the effects occurring more or less simultaneously over a large area of hundreds of square kilometers. The rise in the number of deaths (Fig. 18-4) paralleled the mean daily smoke and sulfur dioxide concentrations daily deaths reached a peak on December 8 and 9, with many of them related to respiratory troubles. Although the deaths decreased when the concentrations decreased, the deaths per day remained considerably above the pre-episode level for some days. Would most of the persons who died have died soon afterward anyway If this were the case, a below-normal death rate would h ve occurred following the episode. This situation did not seem to exist, but detailed analysis was complicated by increased deaths in January and February 1953 which were attributed primarily to an influenza outbreak. 

Fig. 21-11. Contributions to the annual sulfur dioxide concentration from each direction at a receptor in New York by area sources (lines) and point sources (rectangles) for 1969 using the Climatological Dispersion Model,...

From Fig. 21-10, what wind directions are related to highest average winter sulfur dioxide concentrations at this sampling station ... 

TRS Converter To measure hydrogen sulfide and reduced-organic sulfur compounds, the technique used is thermal oxidation, in which sulfur dioxide is produced. Hydrogen sulfide and other reduced-sulfur compounds are measured by using methods applicable to the measurement of sulfur dioxide concentrations. One method is a technique based on ultraviolet fluorescence. 

The emission problem associated with the reverberatory smelting may be solved by electric furnace smelting. In the electric smelting process the quantity of effluent gas can be rather small and the sulfur dioxide concentration can readily be controlled by adjusting the air entrainment into the electric furnace. 

A trash incinerator has an effective stack height of 100 m. On a sunny day with a 2 m/s wind the concentration of sulfur dioxide 200 m directly downwind is measured at 5.0 X 10-5 g/m3. Estimate the mass release rate (in g/s) of sulfur dioxide from this stack. Also estimate the maximum sulfur dioxide concentration expected on the ground and its location downwind from the stack. 

Lead chromate pigments are not sufficiently fast to high sulfur dioxide concentrations. 

Peterson used the skill score to evaluate the performance of his empirical statistical model based on orthogonal functions. The skill score equals 1.0 when all calculated and observed concentrations agree, but 0 when the number of correctly predicted results equals that expected by chance occurrences. The statistical technique had a skill score of 0.304. An 89-day, 40-station set of the data was used to check a Gaussian diffusion model, and this technique gave the diffusion model a skill score of only 0.15. (Recall that the statistical empirical model was used for 24-h averaged sulfur dioxide concentrations at 40 sites in St. Louis for the winder of 1964-1965.)... 

Peterson, J. T. The calculation of sulfur dioxide concentrations over a metropolitan area by using empirical orthogonal functions. American Institute of Aeronautics and Astronautics, Paper 70-113, January 1970. 7 pp. 

Sulfur dioxide in the sample causes a negative interference of approximately 1 mole of ozone per mole of sulfur dioxide, because it reduces the iodine formed by ozone back to potassium iodide. When sulfur dioxide concentrations do not exceed those of the oxidants, a method commonly used to correct for its interference is to add the amount of sulfur dioxide determined by an independent method to the total detector response. A second method is to remove the sulfur dioxide from the sample stream with solid or liquid chromium trioxide scrubbers. Because the data on the performance or these sulfur dioxide scrubbers are inadequate, the performance for each oxidant system must be established experimentally. 

Fujiwara and Reinert et have recently reviewed the subject of pollutant interaction. Fujiwara gave a straightforward reporting of research that is fairly comprehensive, whereas Reinert et al. interpreted and analyzed results. Fujiwara also included some of his data on peas and spinach. His graph (Figure 11-3) showing the greater than additive response of pea to the mixtures of ozone and sulfur dioxide is of interest, because of the linear responses of the two ozone concentrations across sulfur dioxide concentration. Reinert et developed some useftil tabular material, some of which is shown in Tables 11-17 and 11-18. 

Sulfoxyperoxynitrate, 40 Sulfur dioxide concentration, 242 effect on paint, 655... 

Although a variety of environmental exposures involving sulfur dioxide have been linked to human reproductive effects, there is no clear relationship between sulfur dioxide concentrations and adverse reproductive outcomes. ... 

Sulfur dioxide concentrations are currently measured at 253 locations around the United States. The average sulfur dioxide concentration collected at monitoring stations dropped from just over 0.01 ppm in 1982 to under 0.005 ppm in 2001, a decrease of 51 percent. More than half of that decrease (35 percent) occurred between 1992 and 2001. 

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