Nashville Sulfur Dioxide Emission Inventory and the Relationship of Emission to Measured Sulfur Dioxide

A detailed inventory of sulfur dioxide emissions was prepared as part of the Nashville Community Air Pollution Study conducted by the Public Health Service during 1958–59. The primary purpose of the inventory was to provide data for a study of the relationship between the emission of sulfur dioxide and measured ambient levels. The development of the inventory, data collection methods, and calculations are described. Ambient levels of sulfur dioxide were related to average emissions of sulfur dioxide in such a way (correlation coefficient = 0.81) that mean seasonal concentrations of atmospheric sulfur dioxide in square-mile areas could be predicted with fairly good confidence from a knowledge of sulfur dioxide emissions. For these long-period {average) predictions meteorological variables can be disregarded. On a square-mile basis, on the average, one ton of sulfur dioxide emitted per day produced a mean atmospheric sulfur dioxide concentration of 0.022 ppm, and 10 tons of sulfur dioxide per day produced a concentration of 0.067 ppm.     

The Lead Dioxide Estimation Of Sulfur Dioxide Pollution

A new system of measuring sulfation is presented. Because of its simplicity, operation of large sulfation networks can be accomplished at extremely nominal costs. Because of increased sensitivity, present 1 -month sampling time intervals may be shortened to approximately 1 day. Use of this system will permit more definitive investigations of the relationship of sulfation to sulfur dioxide concentration.     

Relationships Between Sulfur Dioxide Concentration Determined By the West-Gaeke and Electroconductivity Methods

Sulfur dioxide concentrations in the atmosphere are commonly determined by the West-Gaeke and electro-conductivity methods. As a part of the United States-Japan Cooperative Air Pollution Measurement Studies, parallel sampling with a 24-hr bubbler, a 1-hr bubbler, and an electroconductivity instrument was conducted in Kawasaki, Japan, between Jan. 12 and Mar. 25 and between Aug. 19 and Sept. 30, 1966. These time periods were chosen because of the seasonal variation in the air pollution levels. Fair agreement was obtained between the 24-hr sample values and the daily mean values of the 24 hourly samples analyzed by the West-Gaeke method. Sulfur dioxide concentrations determined by the electroconductivity method were greater than those determined by the West-Gaeke method, particularly in the winter season. Relationships between the sulfur dioxide concentrations determined by these two methods are discussed.     

江苏省电力行业SO2排放配额分配的探索

研究了江苏省电力行业SO2排放现状,提出利用排放绩效(GPS),并考虑现行环保政策和已定总量控制目标、火电机组容量、热电联产、两控区内外控制等因素分配电力行业SO2排放配额的方法.     

Photo-Oxidation of Sulfur Dioxide

SO₂/O₂ mixtures were photolyzed at 3130 Å and in the range 2500–4000 Å at room temperature. The only product of photolysis was SO₃. Attempts to estimate ф(S0₃) using mass spectrometry, l.R. spectroscopy and pressure change measurements were unsuccessful, because it was not possible to obtain reproducible quantitative estimates of SO₃. ф(SO₂) values were determined by monitoring the 3130 Å absorption for its concentration measurements. ф(SO₂) was independent of SO₂ (11.6 to 50.4 torr) and O₂ (50.0 to 390.6 torr) pressures. At 3130 Å, ф(SO₂) varied between 1.5 × 10^?2 and 2.2 X 10^?2. Over the integrated range 2500–4000 Å ф(SO₂) values of 2.1 X 10^?3 to 2.9 X 10^?3 were obtained. The differences in ф(SO₂) values are explained in terms of wavelength dependence of the rate constants for the two primary reactions: ¹SO₂ + SO₂ → 2SO₂(1) and ¹SO₂ + SO₂ → ³SO₂ + SO₂(2); (k₂/k₁) _{3130 Å} ≈ 10(k₂/k₁)_{2500–4000 Å}.     

The Continuous Analysis of Sulfur Dioxide in Gaseous Samples

Sulfur dioxide is quantitatively scrubbed from atmospheric and stack gas samples through the use of a unique rotary scrubber which provides collection efficiencies in excess of 97% in the PPB through PPM range. The scrubber in addition permits the use of water as a scrubbing vehicle which, when combined with a bleached pararosanaline reagent, provides high specificity and sensitivity for the analysis. By the elimination of the tetrachloromercurate solution, cell staining is eliminated and the stability required for continuous analysis by the reagent is achieved.     

Flash Photolysis of Sulfur Dioxide

The body of information presented in this paper is directed to photochemists and air pollution scientists interested in species which result from the interaction of SO₂ and light. When SO₂ at low pressures is subjected to an intense photolysis flash, the characteristic, very structured SO₂absorption spectrum disappears immediately after the flash and is replaced by a continuous absorption. The continuous absorption gradually decays and the normal SO₂ absorption spectrum returns. The initial absorbance of the continuous absorption is proportional to the square of the SO₂ pressure and the square of the flash irradiance. From these facts we propose the formation of a metastable dimer of SO₂ formed by the collision of two excited molecules. Some properties of this dimer are: natural lifetime = 2 sec; energy above separated monomers = 4 kcal; lifetime at atmospheric pressure = 1 sec (quenching coefficients with several foreign gases = 10^-20 cm³/sec molecule); absorption of ultraviolet light results in photode-composition of the dimer into monomeric SO₂. The long lifetime of this species and its low quenching cross section may make it an important intermediate in photochemical reactions of SO₂. The relatively low excitation energy of the metastable species indicates it may also be an intermediate in thermally excited reactions and perhaps an important component of smoke stack effluent.     

The Absorption of Atmospheric Sulfur Dioxide by Water Solutions

Results of a laboratory study indicate that the rate of solution of atmospheric sulfur dioxide in distilled water, over the range of atmospheric concentrations of 0.81?8.73 mg SO₂/M³, is a function of the concentration of SO2 in the atmosphere, with saturation being reached more rapidly at the higher concentrations. This would indicate that rain water, with constantly renewed surfaces, can be very effective in the removal of atmospheric SO₂. The pH of the exposed water samples reached values of 4.0 or less, comparable to values observed in fog and cloud water near large industrial areas. Overall solubility of sulfur dioxide in distilled water did not follow the law of partial pressure. At the atmospheric concentrations used it was found that over 98.5% of the sulfite in solution was in the form of the bisulfite ion with, the remainder present as unionized sulfurous acid. Computations using the concentration of unionized sulfurous acid in the solution showed that the solubility of this portion of dissolved sulfite did follow the law of partial pressure.     

A Numerical Modeling Technique for Estimating Sulfur Dioxide Dry Deposition Due to Local Source Emissions

This paper describes a methodology for estimating the effect of local source emissions on dry deposition of sulfur dioxide in regions of complex terrain. Airflow in complex terrain is simulated by a time-dependent dynamical model for the meteorological fields. The results of the dynamical model are used to drive a semi-stochastic Lagrangian dispersion model in order to evaluate concentrations resulting from local source emissions. The Lagrangian dispersion model is coupled with a dry deposition treatment which includes the effects of both surface properties and micrometeoroiogical factors on deposition.

A sample application is discussed for a source in the Shenandoah Valley. The largest concentrations and deposition rates were obtained shortly after sunrise, during the transition from the nocturnal to the daytime flow regime. These results suggest that dry deposition may be episodic.     

The Survival of Airborne Serratia marcescens in Urban Concentrations of Sulfur Dioxide

Aerosols of Serratia marcescens ATCC 274 were suspended in a 709L rotating drum at 20 ± 1 °C and high to mid-range relative humidities. At specified times after bacterial aerosolization, sulfur dioxide was added to concentrations of 2.5, or 5 mg/m³. Viable cell decay rate constants, in control aerosols without added sulfur dioxide, increased rapidly from near 100% to 60% RH in the first hour (termed: young aerosol) of suspension, and from a minimum rate constant at 80% in the succeeding four hours (termed: old aerosol).Upon addition of sulfur dioxide to a cloud of S. marcescens, generally, viable cell decay rate constants increased further. One exception was at 80% relative humidity where maximum resistance to SO₂ accelerated death was observed for old aerosols. Cells in young aerosols were particularly sensitive to SO₂ addition at mid-range humidities, while in older aerosols the cells were insensitive to up to 5 mg SO₂/m³ introduced at high RH; but were up to 10 times more sensitive than cells in young aerosols to a given increase (from 2.5 to 5 mg/m³) in SO₂ concentration at mid-range humidities.     

The Relationship of Carbon Dioxide Emissions with Coal Rank and Sulfur Content

Carbon dioxide emissions, on an equivalent energy basis, were calculated for 504 North American coals to explore the effects of coal rank and sulfur content on CO₂ emissions. The data set included coals ranging in rank from lignite through low-volatile bituminous from 15 U.S. states and Alberta, Canada. Carbon dioxide emissions were calculated from the carbon content and gross calorific value of each coal. The lowest CO₂ emissions are calculated for the high-volatile bituminous coals (198 to 211 lbs CO₂/MMBtu) and the highest for lignites and subbituminous coals (209 to 224 lbs CO₂/MMBtu). The lower CO₂ emissions from the high-volatile bituminous coals result in part from their generally higher sulfur content. However, even at equivalent sulfur contents the high-volatile bituminous coals give lower CO₂ emissions than the lower-rank coals. On average, the lowerrank coals produce 5 percent more CO₂ upon combustion than the highvolatile bituminous coals, on the basis of gross calorific value. This difference increases to 9 percent on the basis of estimated net calorific value. The net calorific value is better indicator of power plant energy production than the gross calorific value. The difference in CO₂ emissions resulting from the use of high-volatile bituminous coals and lower-rank coals is of the same order of magnitude as reductions expected from near-term combustion efficiency improvements. These results are useful to those interested in current and future CO₂ emissions resulting from coal combustion.     

Modification of Sulfur Dioxide Injury to Tobacco and Tomato by Varying Nitrogen and Sulfur Nutrition

The body of information presented in this paper is directed to plant scientists who are concerned with factors which modify the susceptibility of plants to air pollutants.

Tobacco and tomato plants grown in sand-solution culture with varying levels of nitrogen or sulfur were exposed to injurious levels of sulfur dioxide. Plants of both species which were deficient in either nutrient exhibited decreased susceptibility to the gas compared with plants grown at optimal levels of each nutrient. Foliage of these plants was also found to have increased stomatal resistance as measured by a porometer and decreased total sulfur accumulations. Plants grown at optimum levels of each nutrient showed increased susceptibility over that of the deficient plants. Stomatal resistance was lower and sulfur accumulation was greater than in the deficient plants. At the supra-optimal nitrogen and sulfur levels, there were differences in susceptibility. Over-abundant nitrogen appeared to decrease susceptibility whereas over-supplies of sulfur increased it.

The response of plants with deficient or optimal supplies of either nutrient might be explained by the effects of nutrition on stomatal activity and hence on ability to absorb SO₂S from the atmosphere, mineral deficiency being known to increase stomatal resistance, and mineral sufficiency, to decrease stomatal resistance by virtue of increased efficiency of water use. The difference in response between plants overfertilized with respect to nitrogen or sulfur is explained by the fact that sulfur is both nutrient and phytotoxicant at the same time. Having already been oyersupplied with sulfur by absorption from the nutrient substrate, the high-sulfur plants were unable to withstand additional sulfur accumulation from the atmosphere and hence were more severely injured.

Increased carbohydrate accumulation in the nitrogen- and sulfur-deficient plants might play an additional role in protection from SO2-injury.     

Simultaneous Sulfur Dioxide and Nitrogen Dioxide Removal by Calcium Hydroxide and Calcium Silicate Solids

ABSTRACT

At conditions typical of a bag filter exposed to a coal-fired flue gas that has been adiabatically cooled with water, calcium hydroxide and calcium silicate solids were exposed to a dilute, humidified gas stream of nitrogen dioxide (NO₂) and sulfur dioxide (SO₂) in a packed-bed reactor. A prior study found that NO₂ reacted readily with surface water of alkaline and non-alkaline solids to produce nitrate, nitrite, and nitric oxide (NO). With SO₂ present in the gas stream, NO₂ also reacted with S(IV), a product of SO₂ removal, on the exterior of an alkaline solid. The oxidation of S(IV) to S(VI) by oxygen reduced the availability of S(IV) and lowered removal of NO₂. Subsequent acidification of the sorbent by the removal of NO₂ and SO₂ facilitated the production of NO. However, the conversion of nitrous acid to sulfur-nitrogen compounds reduced NO production and enhanced SO₂ removal. A reactor model based on empirical and semi-empirical rate expressions predicted rates of SO₂ removal, NO₂ removal, and NO production by calcium silicate solids. Rate expressions from the reactor model were inserted into a second program, which predicted the removal of SO₂ and NO_x by a continuous process, such as the collection of alkaline solids in a baghouse. The continuous process model, depending upon inlet conditions, predicted 30-40% removal for NO and 50-90% removal for SO₂. These x 2 results are relevant to dry scrubbing technology for combined SO₂ and NO_x removal that first oxidizes NO to NO₂ by the addition of methanol into the flue duct.     

Trends in the Extremes of Sulfur Concentration Distributions

ABSTRACT

Understanding the response of air quality parameters such as visibility to the implementation of new air quality regulations, population growth and redistribution, and federal land managing practices is essential to the evaluation of air quality management plans on air quality in federal Class I areas. For instance, the reduction of SO₂ emissions from large single point sources should result in the decrease of extreme sulfate concentrations, while population growth in geographic areas outside of urban centers could cause a slow widespread increase of sulfate and organic concentrations. The change in federal land managing practice of increased prescribed fire on a year-round basis in lieu of large naturally occurring wild fires could have the same effect; that is, the frequency of high sulfur days increase and low sulfur days decrease as the result of the management practice. Therefore, it is of interest to examine the trends associated with the proportion of days during which the concentration of some aerosol species is above or below a certain threshold and decide whether this proportion of days is increasing or decreasing or shows a lack of trend. This is a direct indication of whether the quality of the environment is improving or worsening, or neither.     

Alternative Strategies for Control of Sulfur Dioxide Emissions

Achievement of air quality goals now more than ever requires careful consideration of alternative control strategies in view of national concerns with energy and the economy. Three strategies which might be used by coal-fired steam electric plants to achieve ambient air quality standards for sulfur dioxide have been compared, and the analysis shows that the desired objective can be achieved using the intermittent control strategy with substantially less impact on the environment, less consumption of energy, and at a much lower economic cost than using either stack gas scrubbing or low-sulfur coal.     

Multi-Instrument Performance Evaluation of Conductivity-Type Sulfur Dioxide Analyzers

Three different recording analyzers for sulfur dioxide were operated in parallel under field conditions. Manual sampling for sulfur dioxide using the West-Gaeke procedure supplemented the instrumental evaluation tests. Two of the analyzers were of the continuous-flow type. These were found to give markedly higher readings for SO₂ in the atmosphere (in some cases as much as threefold) than did the other recorder which was sequential-batch or the West-Gaeke manual method.     

The Use of Nahcolite Ore and Bag Filters For Sulfur Dioxide Emission Control

This paper describes some technical and economic aspects of the nahcolite ore injection process for the simultaneous removal of fly ash and sulfur oxides from stack gases. The process is capable of removing greater than 99% of the particulate matter and greater than 70% of the sulfur oxides present in such gases. In the process, nahcolite ore, a naturally occurring material containing 70 to 90% sodium bicarbonate, is ground to 90% passing through —200 mesh screens. Approximately 20% of the ground ore is used to precoat the filter bags in a baghouse filter while the remainder of the material is fed into the flue gas Just ahead of the baghouse. The flue gas is drawn through the baghouse by induced draft fans and sent up the stack. Most of the SO₂ and practically all of the fly ash in the flue gas can be removed as the gas passes through the filter bags. The spent nahcolite ore and fly ash are collected and conveyed to waste disposal as landfill, or alternatively processed for insolubilization by coprecipitation prior to landfilling. The technical feasibility of the process has been demonstrated in both bench scale and pilot scale engineering studies. Economic analyses performed for the cases of plants located in the midwest and southwest indicate lower capital costs for the nahcolite injection process when compared to wet scrubbing. On an annual cost basis, the nahcolite ore Injection process is comparable in cost to wet scrubbing for the case of the southwestern power plant, and somewhat more expensive for the case of the midwestern plant.     

The Characterization of Ozone,Sulfur Dioxide,and Nitrogen Dioxide for Selected Monitoring Sites in the Federal Republic of Germany

Ambient ozone, sulfur dioxide, and nitrogen dioxide data collected at 11 rural gaseous air pollution monitoring stations located throughout the Federal Republic of Germany (FRG) were characterized to provide a basis for investigating the effect these air pollutants may have on forest decline. For any given year, with the exception of the Waldhof site, the ozone monitoring sites did not experience more than 50 occurrences of hourly mean concentrations equal to or above 0.10 ppm. In most cases, the number of occurrences equal to or above 0.10 ppm at the FRG ozone monitoring sites was below the number experienced at a rural forested site located at Whiteface Mountain, New York. Several of the FRG monitoring sites experienced a large number of occurrences of hourly mean ozone concentrations between 0.08 and 0.10 ppm. Hof, Selb, Arzberg, and Waldhof experienced several occurrences of elevated levels of sulfur dioxide concentrations. The nitrogen dioxide 24-h mean concentrations were low for all sites. Because the 24-h mean data may mask the occurrence of a few high concentration events, it is not known if any of the sites that monitored nitrogen dioxide experienced short-term elevated concentrations. To gain further insight into the possible effect of pollutant mixtures on vegetation, future efforts should involve characterizing the timing of multi-pollutant exposures.