Evaluation of the Effectiveness of The Lead Peroxide Method for Atmospheric Monitoring of Sulfur Dioxide

This paper presents a simplified analysis to determine the variables that affect the empirical correlation factor used in the lead peroxide method. The rate of sulfation has been determined from two different models. In the first model, the mass transfer rate is calculated from the gas phase resistance alone whereas in the second model, the diffusion resistance in the gel phase is assumed to be the rate limiting step. Although the gas phase and the gel phase resistances may be both important in the actual case, it has been found that the correlation factor based on the first model is adequate to describe general experimental observations. Reasonable agreement has been obtained between the measured and the calculated va|ue of the correlation factor.     

Oxygenates in Exhaust from Simple Hydrocarbon Fuels

Photochemical air pollution is known to be caused largely by automotive emissions such as hydrocarbons and oxygenated hydrocarbon derivatives. Unlike the hydrocarbons, the contribution of the oxygenates has been virtually unexplored, mainly because of lack of appropriate analytical methods. The objective of this study was to identify and estimate the levels of oxygenated hydrocarbon derivatives in exhaust from simple hydrocarbon fuels. This information is expected to yield ultimately estimates of the relative levels of various classes of oxygenates in exhaust from full-boiling-range gasolines. Identification and measurement of oxygenates in exhaust from the simplified fuels were accomplished using gas chromatography in conjunction with time-of-flight mass spectrometry. The analytical procedure involved concentration of the exhaust organics, followed by a two-stage chromatographic separation of the resultant mixture of oxygenates and hydrocarbons. Identified oxygenates in exhaust from nine test fuels included saturated and unsaturated aldehydes, ketones, and alcohols, as well as ethers, esters, and nitroalkanes; analytical data on organic acids were inconclusive. Of the identified noncarbonyl oxygenates, phenols, cyclic ethers and nitromethane appear to be relatively the most abundant.     

Determination of Oxides of Nitrogen in Combustion Effluents with a Nitrate Ion Selective Electrode

The nitrate ion selective electrode was investigated as an alternative approach to the present colorimetric determination of nitrate resulting from oxidative absorption of nitrogen oxides from combustion effluents. The electrode offers advantages of speed and relatively simple experimental procedure. Replicate measurements of 10^?4–10^?2M nitric acid solutions using bracketing standards show that the electrode approach is capable of good precision (coefficient of variation = ±4%). Comparison of a method utilizing the nitrate electrode with the more laborious phenol disulfonic acid method for the measurement of nitrogen oxides in both oil and gas fired combustion effluents showed agreement within 4% of the mean even in the presence of high levels of SO₂. The correlation coefficient found for PDS vs nitrate electrode is 0.987.     

Air Pollution Control of an Electric Furnace Steelmaking Shop

The body of information presented in this paper is directed to design engineers, operating management and others who may be concerned with the prevention of atmospheric emissions from electric arc steelmaking furnaces. Inland Steel Co. has recently begun operating its first electric furnace shop. Air pollution control equipment for the shop was installed to meet or exceed the legal requirements of applicable air pollution ordinances and regulations. General shop production requirements were established at 100 tons of steel per hour (maximum) to meet sales forecasts and intermediate production facility requirements. Conventional swing roof furnace design was selected for the pair of furnaces in the shop.     

Modifications to an H2S Tape Sampler for Increasing Sensitivity and Accuracy in H2S Sampling

The tape samplers using lead acetate impregnated paper tapes for continuous hydrogen sulfide sampling are subject to a number of errors which can throw considerable doubt on the accuracy of H₂S concentrations being measured. Some of the errors have been minimized with a change in the humidification system and a reduction of the lamp intensity in the optical system.     

Jet Aircraft Operations: Impact on the Air Environment

This paper is directed to those concerned with the air environment and its degradation by the burden of pollution from jet aircraft operations. A summary is presented of the results of a comprehensive air pollution study of jet aircraft operations at the Los Angeles International Airport (LAX). Included in the data obtained from this study are jet engine exhaust measurements for currently used turboprop, turbojet and turbofan engines; measurements of specific contaminants in the atmosphere inside and outside of passenger terminals and ticketing areas, and in aircraft cabins during ground operations including passenger loading and taxiing prior to takeoff; also presented are ambient air measurements in a two-mile radius of the airport. An evaluation is made of the emissions of contaminants from air transport operations and all related ground activities including motor vehicles, that contribute to the total atmospheric contaminant burden at the airport.     

A Load Shifting Model for Air Pollution Control in the Electric Power Industry

Load-shifting, a relatively inexpensive approach to air pollution control, involves transferring the generating load from one power plant to another according to meteorological conditions. In this paper, an atmospheric dispersion model is adapted to estimate the exposure of the urban population to sulfur dioxide from operating the power system in different ways. Then a mathematical model of the power system of a metropolitan area is constructed to determine the reduction in pollution exposure which could be achieved, and the costs involved. As a case study, the application of the model to St. Louis, Missouri, is simulated. Under favorable conditions, load shifting could reduce pollution exposure up to 95%, while increasing the costs of electric power generation by only 4%. The load-shifting model has use not only as an operational control strategy, but also as an analytical tool to evaluate alternative pollution control measures in the electric power industry.     

The Inhibition of Photochemical Smog

Additional inhibitors for the conversion of NO to NO₂ in C3H6—NO—0₂ irradiated mixtures have been tested at 25°C. These mixtures initially contained 16 mTorr C₃H₆, 8 mTorr NO, 0.012 mTorr NO₂, additive, and enough O₂ to bring the total pressure to 100 Torr. The NO₂ pressure was monitored photometrically. In the absence of additive, the NO₂ pressure first increases with irradiation time reaching a maximum conversion at about 15 minutes. As the irradiation time increases beyond 15 min, the NO₂ pressure drops. Before adding the inhibitors, runs were done with 10 Torr of CO added, and in these runs the conversion was speeded so that the maximum in NO₂ pressure occurred at 10 min. This enhancement in conversion rate is considered to be diagnostic for the presence of HO radicals. Next 10-min irradiations were done with various amounts of hexafluorobenzene (C₆F₆), nitrobenzene (C₆H₅NO₂), or naphtha lene (C₁₀H₈) added. The NO₂ pressure was reduced to one-half its value in the absence of inhibitor with 270 mTorr C₆F₆’, 220 mTorr C₆H₅N0₂, or 4 mTorr C₁₀Hg. The C₁₀H₈ is a very efficient inhibitor, but additions of up to 1 8.5 mTorr C₁₀H₈ did not reduce the N0₂ pressure to zero. Studies of the percent conversion of NO to NO₂ vs. irradiation time were done with either 4.2 mTorr C₁₀H₈ or 40 mTorr 2,6-di-ferf-butyl-4-methylphenol (Ph) added. In the former case the peak conversion was delayed from 15 to 22 min, while in the latter case no delay occurred. However, with the Ph added, there appeared to be some reduction in the maximum value of percent conversion.     

Sulfur Dioxide Fumigation of Soybeans: Effect on Yield

In order to determine the influence of SO₂ fumigation of soybean plants on yield, a three-year experiment was conducted on 485 plois of soybeans. Single fumigations of S0₂ were applied at 10 different stages of growth in 1968-69 and 7 stages of growth in 1970. A linear relationship was found to exist beiween the percent of leaf area destroyed and ihe percent crop loss with a significant regression coefficient of b = —0.659, or iwo-thirds of one percent crop loss for each percent of area destroyed. No definite significant stage-of-growth effect was found and no treatment effects were significant for the early stages of growth from the 3-leaf to the 15-leaf stage, nor was there any loss in yield without visible leaf injury.