SO2 concentrations near tall stacks

A study was conducted to investigate plume dispersion during convective (stability class A) conditions. The purpose of the study was to determine if high concentrations occur near sources (1.2–1.8 km) with tall stacks and to identify the plume behavior during these episodes. The study was conducted at the Tennessee Valley Authority's Paradise Steam Plant.The highest concentrations were measured near the source during wind shear capping conditions, which normally correspond to stability class B or C conditions. The measured data are compared with results obtained using a convective boundary layer model and a steady-state Gaussian model.     

Terrain-induced downwash effects on ground level SO2 concentrations

A field study was conducted at the Tennessee Valley Authority's (TVA) Widows Creek Steam Plant from March to 1 May 1979 to investigate the effects of terrain-induced downwash. The Widows Creek Plant is located in a valley formed by Sand Mountain to the southeast and the Cumberland Plateau to the northwest. With southeasterly winds, a downward component of velocity is induced by the terrain as the air moves from Sand Mountain across the valley. Because of the proximity of the plant to Sand Mountain, the plumes are caught in this terrain-induced downwash, which then causes a significant increase in the ground level SO₂ concentrations.An SO₂-monitoring network was established in the downwash region and the measured SO₂ concentrations were correlated with the meteorological parameters and plant operating conditions.The maximum SO₂ concentrations were measured within 1.3 km of the source at locations approximately perpendicular to the Sand Mountain ridge line. The ground level concentration per unit emission rate increased with increasing wind speed and the ratio of wind speed to stack exit velocity.Neither the magnitude nor the trends predicted by the CRSTER model compared well with measured data unless the plume was assumed to be suppressed by the terrain-induced downwash. The CRSTER model predicted a maximum concentration for class A stability and negligible values for class D to G. Ground level concentrations were not measured during the few periods of class A stability that occurred. The highest concentrations were measured for stability class C and D conditions.     

Factors influencing the variability of SO2 concentrations in Istanbul

The correlation between sulfur dioxide (SO2) concentrations measured at the European and Asian sides of Istanbul and meteorological parameters is investigated using principal component analysis (PCA) and multiple regression analysis techniques. Several meteorological parameters are selected to represent the atmospheric conditions during two winter periods: 1993-1994 and 1994-1995. Six principal components are found to explain the majority of the observed meteorological variability. Surface pressure, 850-mb temperature, and surface zonal (east-west) and meridional (north-south) winds show high loadings on separate factors identified by PCA. We seek dominant meteorological parameters that control the SO2 levels at each monitoring station. Several multiple regression analysis models are fitted to the data from each monitoring station using six principal components and previous-day SO2 concentrations as independent variables. Results suggest that the most important parameters, highly correlated with SO2 concentrations in the Istanbul metropolitan area, are atmospheric pressure and surface zonal and meridional winds. These components have more influence on the determination of the air pollution levels at the Asian side than at the European side.     

The change in O3, SO2 and NO2 concentrations in Lithuania

Due to the dynamic nature of the atmosphere, substantial amounts of gaseous and particulate pollutants are transported to the areas distant from their sources. In order to determine the regional concentration levels of atmospheric pollutants in Lithuania, concentrations of gaseous O₃, SO₂, NO₂ and other pollutants have been measured at the Preila background station (55°20′ N and 21°00′ E, 5 m a.s.l.) since 1981. The long-term concentration data set enabled us to get temporal trends, both on a seasonal and longer time scale, to identify source areas of pollutants and to relate them to the emission data. Based on the data obtained, the different tendencies in the pollutant concentration changes were revealed. Positive trends for ozone (of 2.9% per year during 1983–2000) and a distinct negative trend for both sulphur dioxide (of 3.8% per year during 1981–2000) and nitrogen dioxide (of 3.8% per year during 1983–2000) were found. The air mass back-trajectory analysis was used to assess the source region of air pollutants transported to Lithuania. The pollutant concentration levels were compared with their emission changes in Europe and Lithuania. The general trends in SO₂ as well as in NO₂ concentrations observed are consistent with changes in SO₂ and NO₂ emissions in Europe and Lithuania.     

Impacts of some meteorological parameters on SO2 and TSP concentrations in Erzurum, Turkey

The air pollution is the one of the most important environmental problems in Erzurum, situated in the eastern of Turkey, during winter periods. The unfavorable climate as well as the city’s topography, and inappropriate urbanization cause serious air pollution problems. The air pollutant concentrations in a city have a close relationship with its meteorological parameters. In the present study, the relationship between daily average total suspended particulate (TSP) and sulphur dioxide (SO₂) concentrations with meteorological factors, such as wind speed, temperature, relative humidity, pressure and precipitation, in 1995–2002 winter seasons was statistically analyzed using the stepwise multiple linear regression analysis. According to the results obtained through analysis, higher TSP and SO₂ concentrations are strongly related to colder temperatures, lower wind speed, higher pressure system and weakly lower precipitation and higher relative humidity. The statistical models of SO₂ and TSP including meteorological parameters gave R² of 0.74 and 0.88, respectively. Furthermore, the correlation between the previous day’s SO₂, TSP concentrations and actual concentrations of these pollutants on that day was investigated and found as 0.84 and 0.53, respectively. In order to develop this model, previous day’s SO₂ and TSP concentrations were added to the equations. The new model for SO₂ enhanced considerably (R² = 0.92), but for TSP new model was not enhanced (R² = 0.89).     

Effects of air filtration at small SO2 and NO2 concentrations on the yield of barley

Two cultivars of Igri and Gerbel winter barley Horteum vulgare L. were grown in open-top chambers in filtered and unfiltered air at a site with approximately 10 nl litre(-1) SO2 and 12 nl litre(-1) NO2 (seasonal mean). The experiment ran for three consecutive seasons 1982-1983, 1983-1984, 1984-1985, and significant effects of filtration were observed for each crop. In years 1982-1983 and 1984-1985, the crops in unfiltered air yielded larger grain dry matter, 9% in 1982-1983, and 8% in 1984-1985. For both crops, the differences were statistically significant at the 5% level. Differences were also observed for the remaining above-ground dry matter, and these were consistent in direction in each year but statistically significant only in 1984-1985. In both growing seasons (1982-1983 and 1984-1985), there were no major pest infestations and no long-term water stress or photochemical ozone episodes. In the remaining experiment (1983-1984) similar air concentrations of SO2 and NO2 produced effects of the opposite sign to those observed in 1982-1983 and 1984-1985. Significant reductions in grain yield (13%) were obtained in unfiltered air. The only major environmental difference for the 1983-1984 crop was a notable dry period in May and June 1984 with marked water stress in the crop, requiring irrigation. These results suggest that the relationship between yield and pollutant concentration may be confounded by additional stresses, many of which are a common component of the growing season for major crops.     

A semiparametric statistical approach for forecasting SO2 and NO x concentrations

This study develops a new semiparametric statistical approach for urban air quality forecasting. Compared to conventional approaches, the semiparametric approach allows the model users to benefit from the positive aspects and alleviate the negative ones of parametric and nonparametric approaches. Two advantages of the approach lie in (1) the interpretation of the data set being easily decoded and used by the model and (2) its capability in dependence on prior assumption. To illustrate the performance of the proposed approach, three semiparametric regression models (i.e., linear-, quadratic-, and interactive-based semiparametric regression) are applied to an air quality forecasting problem in the city of Xiamen, China, and satisfactory training and prediction performance are obtained. The three models are also compared to three parametric and two nonparametric regression models. The results indicate that the predictive accuracy of semiparametric regression models is higher than those obtained from the parametric and stepwise cluster analysis models. However, the proposed three semiparametric regression models could be much favored, since they can be achieved more easily and rapidly than the artificial neural network model.     

Trade-driven relocation of ground-level SO2 concentrations across Chinese provinces based on satellite observations

Environmental Science and Pollution Research - The influence of trade on ground-level SO2 concentrations in China was evaluated based on multiregional input–output (MRIO) analysis, using the...     

Effects of SO2 and NOx emission reductions on PM2.5 mass concentrations in the southeastern United States

Measurements from sites of the Southeastern Aerosol Research and Characterization (SEARCH) program, made from 1998 to 2001, are used with a thermodynamic equilibrium model, Simulating Composition of Atmospheric Particles at Equilbrium (SCAPE2), to extend an earlier investigation of the responses of fine particulate nitrate (NO3-) and fine particulate matter (PM2.5) mass concentrations to changes in concentrations of nitric acid (HNO3) and sulfate (SO42-). The responses were determined for a projected range of variations of SO42- and HNO3 concentrations resulting from adopted and proposed regulatory initiatives. The predicted PM2.5 mass concentration decreases averaged 1.8-3.9 microg/m3 for SO42- decreases of 46-63% from current concentrations. Combining the S042- decrease with a 40% HNO3 decrease from current concentrations (approximating expected mobile-source oxides of nitrogen [NOx] reductions by 2020) yielded additional incremental reductions of mean predicted PM2.5 mass concentration of 0.2 microg/m3 for three nonurban sites and 0.8-1 microg/m3 for one nonurban and two urban sites. Increasing the HNO3 reduction to 55% (an estimate of adding Clear Skies Phase II NOx reductions) yielded additional incremental reductions of mean predicted PM2.5 mass concentration of 0-0.4 microg/m3. Because of the well-documented losses of particulate NO3- from Federal Reference Method (FRM) filters, only a fraction of these incremental changes would be observed.     

Combined analysis of modeled and monitored SO2 concentrations at a complex smelting facility

Vale Canada Limited owns and operates a large nickel smelting facility located in Sudbury, Ontario. This is a complex facility with many sources of SO₂ emissions, including a mix of source types ranging from passive building roof vents to North America's tallest stack. In addition, as this facility performs batch operations, there is significant variability in the emission rates depending on the operations that are occurring. Although SO₂ emission rates for many of the sources have been measured by source testing, the reliability of these emission rates has not been tested from a dispersion modeling perspective. This facility is a significant source of SO₂ in the local region, making it critical that when modeling the emissions from this facility for regulatory or other purposes, that the resulting concentrations are representative of what would actually be measured or otherwise observed. To assess the accuracy of the modeling, a detailed analysis of modeled and monitored data for SO₂ at the facility was performed. A mobile SO₂ monitor sampled at five locations downwind of different source groups for different wind directions resulting in a total of 168 hr of valid data that could be used for the modeled to monitored results comparison. The facility was modeled in AERMOD (American Meteorological Society/U.S. Environmental Protection Agency Regulatory Model) using site-specific meteorological data such that the modeled periods coincided with the same times as the monitored events. In addition, great effort was invested into estimating the actual SO₂ emission rates that would likely be occurring during each of the monitoring events. SO₂ concentrations were modeled for receptors around each monitoring location so that the modeled data could be directly compared with the monitored data. The modeled and monitored concentrations were compared and showed that there were no systematic biases in the modeled concentrations.

Implications:

This paper is a case study of a Combined Analysis of Modelled and Monitored Data (CAMM), which is an approach promulgated within air quality regulations in the Province of Ontario, Canada. Although combining dispersion models and monitoring data to estimate or refine estimates of source emission rates is not a new technique, this study shows how, with a high degree of rigor in the design of the monitoring and filtering of the data, it can be applied to a large industrial facility, with a variety of emission sources. The comparison of modeled and monitored SO₂ concentrations in this case study also provides an illustration of the AERMOD model performance for a large industrial complex with many sources, at short time scales in comparison with monitored data. Overall, this analysis demonstrated that the AERMOD model performed well.     

The Effect of Analytical Method on Indicated Atmospheric SO2 Concentration

Atmospheric samples collected in several American cities were analyzed for SO₂ concentration using various analytical methods. The methods were: (1) electroconductivity, (2) West-Gaeke, (3) West-Gaeke with membrane prefdter, (4) West-Gaeke with glass-fiber prefilter, (5) hydrogen peroxide, (6) hydrogen peroxide with membrane prefilter, and (7) hydrogen peroxide with glass-fiber prefilter. The relationships among SO₂ data produced by these methods were evaluated statistically. Where statistical differences among methods, at the 95% confidence level, were determined then relationships were further delineated. Factors considered in these comparisons were: (1) location, {2) time of day, (8) concentration range, (4) particulate concentration, and (5) humidity. Laboratory evaluations of these methods show that each method is subject to different interfering substances. Laboratory evaluations of these methods show that each method is subject to different interfering substances. The relationship among methods obtained in these studies will complement these data and perhaps provide for further laboratory and field evaluation of methods used to measure SO₂. The relationship among SO₂ data produced by these methods should be useful in relating atmospheric SO₂ concentration to its effects and to those involved in establishing ambient air quality standards.     

Response of needle sulphur and nitrogen concentrations of Scots pine versus Norway spruce to SO2 and NO2

The results of two field studies and an open-top chamber fumigation experiment showed that the response of mature Scots pine to SO(2) and NO(2) differed from that of mature Norway spruce. Moreover, the response of pine seedlings to SO(2) and NO(2) differed from that of mature trees. The greater increase in the needle total S concentrations of pine suggested more abundant stomatal uptake of SO(2) compared to spruce. Both pine seedlings and mature trees also seemed to absorb more N from atmospheric deposition. Mature pine was able to assimilate SO(4)(2-) derived from SO(2) into organic S more effectively than mature spruce at the high S and N deposition sites, whereas both pine and spruce seedlings accumulated SO(4)-S under NO(2)+SO(2) exposure. Spruce, in turn, accumulated SO(4)-S even when well supplied with N. Net assimilation of SO(4)(2-) in conifer seedlings was enhanced markedly by elevated temperature. To protect the northern coniferous forests against the harmful effects of S and N deposition, it is recommended that the critical level for SO(2) as a growing season mean be set at 5-10 microg m(-3) and NO(2) at 10-15 microg m(-3), depending on the 'effective temperature sum' and/or whether SO(2) and NO(2) occur alone or in combination.     

A numerical model for the simulation of SO2 concentrations in the Kyongin region,Korea

A method for solving the non-reactive tracer continuity equation using a time splitting technique and a Galerkin technique with chapeau functions as finite elements for the horizontal advection has been developed and employed to simulate SO₂ concentrations in the Kyongin region in Korea for a synoptic case of high pollution potential days in autumn with the relatively strong southwesterly geostrophic wind at the 850 hPa pressure level. The paired comparisons between hourly observed and the simulated SO₂ concentrations are made to test the model performance. The result indicates that the present model simulates quite well horizontal distribution patterns of SO₂ concentration. However, the simulated concentrations depend largely on the emission rate, suggesting the importance of accurate source identification for the accurate simulation of the concentration field.     

Effect of SO2 on the reproduction of pea aphids, Acyrthosiphon pisum, and the impact of SO2 and aphids on the growth and yield of peas

Pea aphids feeding from birth to maturity on pea plants (Pisum sativum) exposed to SO(2) concentrations of 50 nl litre(-1) or 80 nl litre(-1) showed a significant 19% increase in the rate of nymph production during the reproductive period, compared to control aphids feeding on plants in charcoal-filtered air. The higher nymph production resulted in a mean 4.6% increase in the intrinsic rate of population increase (rm). In longer term glasshouse fumigation experiments pea aphid populations were, on average, 1.8 times greater on pea plants in ambient air plus 45 nl litre(-1) SO(2) than in ambient air alone. Aphid infestation in ambient air caused a 42% reduction in pea yield and affected most plant parameters adversely. Ambient air plus SO(2) had no direct effect on yield, but, in combination with aphid infestation, a further 10% reduction in yield was recorded.     

SO2的生物监测与防治

SO2是我国大气的主要污染物之一，一般大气中的SO2多采用化学法监测，而生物对SO2的监测具有独到的作用，文中就SO2对人类的危害和生物监测及防治进行了初探。     

Sensitivity of Native Desert Vegetation To SO2 and to SO2 and NO2 Combined

Interest in air pollution injury to native vegetation has been generated with the construction and planned construction of large coal-fired power plants near the coal reserves in the southwest desert areas of the United States. Since information on the effects of SO₂ on these native species was not available in the literature, fumigation studies were conducted with portable chambers placed over native species in the field with SO₂ and SO₂ + NO₂. Pollutant concentrations were measured and controlled with instruments located in a mobile laboratory. Each fumigation was of two hours duration and the concentration ranged from 0.5 to 11 ppm SO₂ and from 0.1 to 5 ppm NO₂. Concentrations of SO₂ above 2 ppm were required to cause injury to all but a few of the 87 species studied. Many of the native desert species proved to be highly resistant to injury from these gases.     

酸碱改性对活性焦烧结烟气脱硫性能的影响

选取一定目数范围的活性焦,用3种酸(HCl、H2SO4和HNO3)、3种碱(KOH、NaOH和NH3·H2O)和酸碱两步(HNO3和KOH)对其进行改性处理,对比这几种方法改性的活性焦对烧结烟气的脱硫性能,实验结果表明,20~40目范围的活性焦脱硫性能最好;HCl改性活性焦的脱硫性能基本无变化,HNO3改性后有促进作用但作用不大,H2SO4改性反而降低了活性焦的脱硫活性;KOH和NaOH溶液改性活性焦对其脱硫性能有很大的提升作用,其中KOH改性效果更好,NH3·H2O改性基本无影响;先KOH后HNO3两步改性的活性焦效果最佳,并且能维持一定时间100%的脱硫效率。     

Time series study of concentrations of SO4(2-) and H+ in precipitation and soil waters in Norway

Along with a steady reduction of acid inputs during 14 years of intensive forest monitoring in Norway, the influence of acid deposition upon soil water acidity is gradually reduced in favour of other and internal sources of H+ and sulphate, in particular from processes in the upper soil layer. We used statistical analyses in two steps for precipitation, throughfall and soil water at 5, 15 and 40 cm depths. Firstly, we employed time series analyses to model the temporal variation as a long-term linear trend and a monthly variation, and by this filtered out residual, weekly variation. Secondly, we used the parameter estimates and the residuals from this to show that the long term, the monthly and the weekly variation in one layer were correlated to similar temporal variation in the above, adjacent layer. This was strongly evident for throughfall correlated to precipitation, but much weaker for soil water. Continued acidification in soil water on many plots suggests that the combined effects of anthropogenic and natural acid inputs exceed in places the buffering capacity of the soil.