The characteristics of size distribution of suspended particulates in the air for sulphates and selected metals in different areas and seasons

The characteristics of the distribution of particles by size were investigated for sulphates and selected metals (Pb, Fe, Mn, and Cu) in the air in two urban and an industrial area during the winter and summer periods using an Andersen cascade impactor.In the case of metals, but not sulphates, the character of the area affected the value of mass median diameter. Lowest values were obtained in a sparsely populated urban area, whereas in a densely populated urban area and in the industrial area the values were higher.In the industrial area a high correlation coefficient was found between sulphate and manganese, and between sulphate and lead, as well as a high value of the equivalent Mn²⁺/SO _inf4 ^sup2- ratio for the total sample. It may therefore be assumed that in the industrial area manganese produces a catalytic effect on SO₂ conversion to sulphate. Among the investigated metals lead stands out as a dominant cation which binds to the sulphate ion in the industrial and densely populated areas.     

Detection of sulphur dioxide in the air using Scotch pine needles

Air quality is especially important in surface layers, for it is this layer that provides the living components of environment with the needed oxygen and carbon dioxide. Various air polluting gases penetrate cells affecting and contaminating them. Chloroplast shell of some pine species, for instance, doubles under the impact of carbon dioxide which is followed by tillacoids swelling and reduction.Literature provides opinions of some authors, who consider Scotch pine needle to be a biological indicator of sulphur dioxide. Others object to it basing on the observations of physiological development.The property of a Scotch pine as that of biological indicator manifests in SO₂ absorption by its needles. The analysis of total content of SO₂ in the needles shows an increase of SO₂ concentration.Sulphur in the needles is found in the form of organically bound sulphur, aminoacids, hormones as well as in the form of sulphates.Basing on our previous analysis we have generalized the data on the correlation concentrations of sulphur dioxide in the air and general concentrations of sulphur in the needles. We have supplemented the observations with the analyses of organically bound sulphur and concentrations of nonorganic sulphur. According to research data, needles contain a characteristic and rather stable quantity of organically bound sulphur.So we may state that the SO _inf4 ^sup2– concentration and the amount of SO₂ absorbed from the air are interdependent.Some authors state that SO _inf4 ^sup2– content in the soil doesn't affect sulphur content in pine needles. That is why we studied the affect of SO _inf4 ^sup2– content in the soil on sulphur content in Scotch pine needles.We could prove this statement by means of various kinds of analyses only partially. The ion transport is affected by the presence of other ions, pH and a lot of other factors.What may be said for sure is that different qualities of soils gave only minor and insignificant deviations.Hence our assumption about the SO₂ contamination from air, proved by its effect on the soils, turns to suit approximate measurements.     

Reduction of SO2 emissions by ammonia gas during unstaged combustion

The reduction of SO₂ by the addition of ammonia gas has been studied in a 2 m high fluidized bed combustor having a 30 cm static bed height and a freeboard height of 170 cm. Ammonia gas was injected at 52 cm above the distributor where the temperature is ca. 700° C by an uncooled stainless steel tube injector. Experiments were carried out to investigate the effects of amminia gas injection on sulphur dioxide emissions at unstaged conditions of: (i) excess air level, (ii) NH₃:SO₂ molar ratio, (iii) fluidizing velocity and (iv) bed height.A maximum reduction of 75% in SO₂ emissions was found at 40% excess air, at an NH₃:SO₂ molar ratio of 5.4. The onset of SO₂ reduction occurred at an NH₃:SO₂ ratio of 1.5 However, the most effective ratio was found to be between 3 and 5. Fluidizing velocity and bed height were also found to have significant influence on SO₂ reduction.It is difficult to determine how the SO₂ reduction varied with operating conditions. When ammonia is added in the main combustor zone, the temperature is much higher than that required for the occurrence of sulphur dioxide-ammonia and sulphur trioxide-ammonia reactions. However, this paper points out the significance of ammonia addition in the reduction of sulphur dioxide.     

Seasonal Differences in the Levels of Gaseous Air Pollutants in the Vicinity of a Waste Dump

Hydrogen sulphide, ammonia, nitrogen dioxide, mercaptans and sulphur dioxide (H₂S, NH₃, NO₂, R-SH, SO₂) concentrations were measured at the location in the vicinity of the waste dump to determine the air pollution level of these pollutants prior to the operation of the Mobile Thermal Treatment Plant. Samples were collected over one year period. Seasonal differences, and the influence of meteorological parameters (temperature, relative humidity, pressure and wind direction) on the air pollution levels were studied. Results show relatively low concentrations of H₂S, NO₂, R-SH and SO₂, while NH₃ levels were higher compared to the guideline values. Good weather conditions (high air pressure and low relative humidity) are connected to long range transport of NO₂, while higher temperatures result in elevated NH₃ and R-SH concentrations. Because of the predominant northeast wind direction (the same as the waste dump direction), the contribution of air pollution from the direction of the waste dump at the measuring site is significant, but that does not necessarily mean that the pollutants originated from that source.     

Air Quality Status of an Open Pit Mining Area in India

This investigation presents the assessment of ambient air quality carried out at an open pit coal mining area in Orissa state of India. The 24-h average concentrations of suspended particulate matter (SPM), respirable particulate matter (RPM, particles of less than 10 m aerodynamic diameter), sulphur dioxide (SO₂) and oxides of nitrogen (NO_x) were determined at regular interval throughout one year at 13 monitoring stations in residential area and four stations in mining/industrial area. During the study period, the 24-h and annual average SPM and RPM concentrations exceeded the respective standards set in the Indian ambient air quality standard (NAAQS) protocol in most of the residential and industrial areas. However, the 24-h and annual average concentrations of SO₂ and NO_x were well within the prescribed limit of the NAAQS in both residential and industrial areas. A management strategy is formulated for effective control of particulate matter at source and other mitigative measures are recommended including implementation of green belts around the sensitive areas.     

Elimination of ammonia interference in acidimetric determination of sulphur dioxide

Ammonia interference in acidimetric determination of sulphur dioxide can be eliminated by separate determination of ammonia in the same sample and by correction of results. However, with this addition the procedure is no longer simple.To avoid two separate determinations a selective absorption of ammonia from the air stream before it enters the absorbent solution for SO₂ has been considered. Several absorbents used to remove or to collect ammonia for subsequent determination were tested in the laboratory. Whatman No. 1 (or 41) filter papers impregnated with 3% oxalic acid solution in ethanol proved to be the most efficient for ammonia retention without an effect on SO₂. In a comparative testing over 52 days at a permanent sampling station no statistically significant difference was observed between two trains with impregnated filters and a third train where correction for ammonia, separately determined in the same sample, was performed.Regression analysis, however, showed that the results obtained in the third train are more dispersed due to accumulated errors in two analyses at low concentration levels further aggravated by conversion of ammonia to equivalent SO₂ concentrations. The removal of ammonia with impregnated filters gives better precision with less inconvenience and is therefore preferable.     

2014—2018年洛阳市大气污染变化特征及影响因素研究

研究采用空气质量指数法对2014—2018年洛阳市大气污染变化特征进行了分析,构建了空气污染物浓度的影响指标体系,采用灰色关联法研究了空气污染物浓度与影响因子之间的关联度,得到了影响空气污染物浓度的主要指标因子,并提出了改善洛阳市空气质量的措施。结果表明:洛阳市空气质量指数类别主要为良和轻度污染。2014—2018年空气质量为优良的天数主要出现在春季、夏季和秋季,重度污染和严重污染主要出现在冬季。2018年PM₁₀、PM_2.5、NO₂、SO₂和CO这5项污染物浓度随时间变化呈"V"型,污染主要集中在1—5月和11—12月。O₃浓度随时间变化呈倒"V"型,污染主要集中在4—9月。研究期内PM_2.5、PM₁₀和O₃是主要污染物。市区总人口、工业(综合)能源消耗量、人均生产总值、城市机动车总数、城市房屋施工面积、人均公园绿地面积、建成区绿化覆盖率和一般工业固体废物产生量等8项指标因子与PM_2.5、PM₁₀和O₃的浓度表现出高关联度或较高关联度。     

Higher Plants As Bioindicators Of Sulphur Dioxide Emissions In Urban Environments

The evaluation of certain vascular plants that grow in the city of Madrid as biomonitors of SO₂ air pollution in urban environments has been carried out. Total concentration of sulphur in leaves of the chosen higher plants as well as other parameters in close relation to this contaminant (visible injury symptoms, chlorophyll a- and b-content and peroxidase activity) have been determined in order to study the spatial distribution and temporal changes in SO₂ deposition. Results obtained show that coniferous species such as Pinus pinea, were more sensitive to SO₂ atmospheric concentration than leafy species as Quercux ilex subspecies ballota and, in the same way, bush species, such asPyracantha coccinea and Nerium oleander, were more sensitive than wooded species, such as Cedrus deodaraandPinus pinea, respectively. There is a higher accumulation of sulphur in vegetable species located near highways and dense traffic incidence roads and near areas with high density of population. The minimum values for accumulation of SO₂ were registered in winter and spring seasons (from January to April) due to the vegetative stop; while maximum values are obtained during the summer season (from June to September), due to the stoma opening. The highest increments in sulphur concentration, calculated as the difference between two consecutive months, are obtained in May and June for all considered species except forCedrus deodara and Pyracantha coccinea, both species have few seasonal changes during the whole year. Some species are more sensitive to natural washing than others, showing a decrease in sulphur concentration after rainfall periods.     

The effect of various types of cement dust on sulphur dioxide oxidation in the air

The effect of various types of cement dust on the behaviour of sulphur dioxide in the air was investigated on model systems in different experimental conditions.Experiments were carried out with PC-15z-45s (Portland-blast furnace cement containing 15% blast furnace slag), PC-25p-35s (Portland-pozzolan cement containing 25% pozzolan) and EFD (electrofilter dust).EFD most effectively removed SO₂ from the air stream. The next efficacious was PC-15z-45s, whereas PC-25p-35s was the least efficient. The efficacy of cement dusts for SO₂ removal from the air stream depended on their chemical and granulometric composition and in particular on the size of specific surface.The rate of reaction was also influenced by experimental conditions—relative humidity, the length of contact, that is, the flow rate of gaseous mixture through the reactor, and the amount of cement dust.The experimental data show that in the contact between SO₂ and cement dust catalytic oxidation of SO₂ to sulphates takes place. Sulphates remain bound to the surface, from which they cannot be thermally desorbed, but can be released by extraction in the Soxhlet apparatus.     

Investigating the impacts of some meteorological parameters on air pollution in Balikesir, Turkey

Air pollution is one of the most important environmental problems in Balikesir, situated in the western part of Turkey, during the winter periods. The unfavorable climate as well as the city’s topography, and inappropriate fuel usage cause serious air pollution problems. The air pollutant concentrations in the city have a close relationship with meteorological parameters. In the present study, the relationship between daily average total suspended particulate (TSP) and sulphur dioxide (SO₂) concentrations measured between 1999–2005 winter seasons were correlated with meteorological factors, such as wind speed, temperature, relative humidity and pressure. This statistical analysis was achieved using the stepwise multiple linear regression method. According to the results obtained through the analysis, higher TSP and SO₂ concentrations are strongly related to colder temperatures, lower wind speed, higher atmospheric pressure and higher relative humidity. The statistical models of SO₂ and TSP gave correlation coefficient values (R ²) of 0.735 and 0.656, respectively.     

烟花爆竹禁燃对春节期间东北地区空气质量影响评估

利用2015—2017年春节期间东北地区主要大气污染物(PM_(10)、PM_(2.5)、SO_2、NO_2、CO和O3)质量浓度监测资料及相应气象因子(温度、湿度、风速和气压)观测资料,分析了春节期间烟花爆竹禁燃对东北地区空气质量的影响。结果表明:随着东北地区主要城市禁燃力度的增强,空气质量逐年提升,PM_(2.5)和SO_2浓度逐年大幅度下降。禁燃可明显降低城区PM_(2.5)浓度,而由于春节期间污染源整体减少,城区和城郊监测点PM_(2.5)浓度值差异减小。烟花爆竹对PM_(10)和PM_(2.5)浓度影响高于对气体污染物SO_2、NO_2和CO的影响。此外,气象条件对东北地区春节期间禁燃改善空气质量的效果也有明显影响。因此,结合春节期间的气象条件,在东北地区实施禁燃政策动态调整非常必要。     

Model Assessment of Air-Pollution in Prague

Results of relatively simple gaussian dispersion model are presented. This model, developed in the beginning of this decade, is suitable mainly for determination of spatial distributions of annual mean concentrations of such kinds of air-pollution as sulphur dioxide (SO₂), mixture of nitrogen oxides (NO_x) or suspended particulate matter (SPM) from all types of emission sources located within the city - point sources, line sources and area sources. Model has been used in years 1994, 1996 and 1998 to assess the air-pollution distributions of the above mentioned kinds in the Prague area and the development of the air quality state. It contributed to the decision making process when possible impact of some changes in traffic system or in system of domestic heating, for example, has been investigated. In this contribution, behaviour of sulphur dioxide (SO₂) and mixture of nitrogen oxides (NO_x) ground concentration distributions are analyzed with respect to changing emission situation in Prague in recent years. Results show that SO₂ ground concentration level decreases mainly due to changes in local heating methods and type of fuel used. Different trend can be seen in NO_x ground concentrations thanks to rapid increase in the traffic density.     

Air pollution impact assessment on agroecosystem and human health characterisation in the area surrounding the industrial settlement of Milazzo (Italy): a multidisciplinary approach

In order to evaluate the impact of atmospheric pollutants emitted by the industrial settlement of Milazzo (Italy) on agriculture, sulphur dioxide and ozone levels in air were monitored and the data were used to estimate yield losses of the most widespread cultures. Trace element concentrations in crops and soils were also detected and metabolic profiles of soil microbial communities were considered. Vibrio fischeri test was used to appraise airborne pollutant ecotoxicity and epidemiological studies on causes of death distribution were carried out to characterize health state of people living in the area. All the sampling points were selected in farms on the basis of a theoretical meteo-diffusive model of industrial air pollutants. Experimental SO₂ and O₃ values mainly exceeded the threshold established by Italian and EU regulations to protect vegetation and they correspond to estimated significant crop losses. Conversely toxic element residues in soils and in agroalimentary products were generally lower than the fixed values. SO₂ and O₃ concentrations, toxic element contents and ecotoxicity levels of airborne pollutants were not related only to industrial site emissions, while the fluctuations on metabolic profiles of soil microbial communities seem to agree with the predicted deposition of xenobiotic compounds from the industrial plants. The epidemiological study evidenced a better health state of populations living in the investigated area than in the Messina province and the Sicily region but, inside the area, males living in the municipalities closest to the industrial settlement exhibited a worst health state than those in the very far ones.     

An assessment of air quality in Karachi,Pakistan

An atmospheric pollution survey was carried out at 13 sites in Karachi, Pakistan, simultaneously from 0600 h to 2100 h for 15 consecutive days in May 1990 which also included meteorological measurements. The monitoring sites were included along the prevailing wind patterns in Karachi. Carbon monoxide levels in the ambient air were found to reach 9–10 ppm along the busy urban streets whereas CO₂ level exceeded 370 ppm in these areas. Our survey indicates that NO₂ levels were exceeding U.S. ambient air quality standards. Maxmum NO₂ concentrations were observed (0.3–0.5 ppm) during the daytime from 0600 h to 2100 h. The surface ozone maximum around noon at the inland sites reached the levels of 40 ppb and 50 ppb respectively compared to upwind coastal Sites 1 level of 25 ppb. The Pb concentrations were approximately 3- to 7-fold higher than average, which corresponded well to urban air. Fossil fuel SO₄ (excess) and NO₃ were apportionally based on the assumption that these two anions were present as (NH₄)₂SO₄, and NH₄NO₃ in the aerosols. In the eastern part of the city atmospheric sulphate (SO₄) shows the combustion of coal as its source from the vicinity and downwind of a steel manufacturing plant.     

Use of a MM5–CAMx–PSAT Modeling System to Study SO2 Source Apportionment in the Beijing Metropolitan Region

A coupled MM5–CAMx air quality modeling system was used to simulate SO₂ concentrations in Beijing, China during the heating season. Particulate matter source apportionment technology was employed to investigate the apportionment of SO₂ sources in the study area. Comprehensive analysis of the industry and region revealed that the most important SO₂ contributors were publicly and privately supplied heating emission sources and other industry emission sources from the urban areas of Beijing, with 66.1?% of the emission source contribution ratio. Four SO₂ emission reduction scenarios based on our SO₂ source apportionment research were established to assess the potential for improving the SO₂ air quality in Beijing during the heating season. By weighing the desired SO₂ improvement, the availability of technology, and economic considerations, a suitable SO₂ reduction plan was able to be recommended for Beijing city.     

Photoacoustic measurements of black carbon light absorption coefficients in Irbid city, Jordan

The goal of this work is the analysis of air quality levels in the area of Volos, a city of average size on the eastern seaboard of Central Greece. For this purpose, concentration measurements of sulfur dioxide, nitrogen oxide, and nitrogen dioxide, for a 4-year period (2001–2004) are analyzed. Air pollution data were obtained by a monitoring station, fully automated, which was established by the Hellenic Ministry of the Environment, Physical Planning, and Public Works, in order to measure air pollution levels in Volos, a medium-sized city, which faces the effects of industrialization. The main conclusions from the statistical analysis of the 4-year measurements of hourly SO₂, NO₂, and NO concentrations in the city of Volos, showed that the mean seasonal variation of the examined air pollutant concentration presents a minimum during the warm period of the year and a maximum during the cold period. Although the local geomorphology and meteorology encourage particularly the accumulation of air pollutants, the analysis shows that the SO₂ and NO₂ concentration levels remain lower than corresponding thresholds for human health protection set by the European Union, in this urban measuring site, during the examined period. The application of harmonic analysis revealed the difference between the annual variation of the SO₂ and NO _x concentrations. Regarding NO _x , the variation is mainly due to the first harmonic term (anthropogenic factor), while the SO₂ variation is interpreted by the two harmonic terms, which represent the anthropogenic and meteorological factors, respectively.     

Modeling of SO<Subscript>2</Subscript> distribution in Istanbul using artificial neural networks

Urban air pollution is a growing problem in developing countries. Some compounds especially sulphur dioxide (SO₂) is considered as typical indicators of the urban air quality. Air pollution modeling and prediction have great importance in preventing the occurrence of air pollution episodes and provide sufficient time to take the necessary precautions. Recently, various stochastic image-processing algorithms such as Artificial Neural Network (ANN) are applied to environmental engineering. ANN structure employs input, hidden and output layers. Due to the complexity of the problem, as the number of input–output parameters differs, ANN model settings such as the number of neurons of these layers changes. The ability of ANN models to learn, particularly capability of handling large amounts (or sets) of data simultaneously as well as their fast response time, are invariably the characteristics desired for predictive and forecasting purposes. In this paper, ANN models have been used to predict air pollutant parameter in meteorological considerations. We have especially focused on modeling of SO₂ distribution and predicting its future concentration in Istanbul, Turkey. We have obtained data sets including meteorological variables and SO₂ concentrations from Istanbul-Florya meteorological station and Istanbul-Yenibosna air pollution station. We have preferred three-layer perceptron type of ANN which consists of 10, 22 and 1 neurons for input, hidden and output layers, respectively. All considered parameters are measured as daily mean. The input parameters are: SO₂ concentration, pressure, temperature, humidity, wind direction, wind speed, strength of sunshine, sunshine, cloudy, rainfall and output parameter is the future prediction of SO₂. To evaluate the performance of ANN model, our results are compared to classical nonlinear regression methods. The over all system finds an optimum correlation between input–output variables. Here, the correlation parameter, r is 0.999 and 0.528 for training and test data. Thus in our model, the trend of SO₂ is well estimated and seasonal effects are well represented. As a result, we conclude that ANN is one of the compromising methods in estimation of environmental complex air pollution problems.     

Evaluation of air pollution phytotoxicity in a seasonally dry tropical urban environment

This study was conducted in the urban environment of Varanasi, India, to evaluate the plant responses to urban air pollution. Twenty sites were selected in four different zones of the city. At each site, seven woody perennials of same age classes were selected. Out of the four zones (I, II, III and IV), zone IV was used as a reference (control) zone as it received the minimum pollution input. Plant species growing in polluted and control areas were compared with respect to foliar dust load, per cent leaf area injury, leaf area, specific leaf weight and chlorophyll, ascorbic acid, SO ₄ ^2– S and total N concentration in the leaves. Results indicated that the air pollution level in Varanasi causes leaf damage, reduces leaf area, specific leaf weight and chlorophyll, ascorbic acid and total N concentrations in the leaves. Sulphur concentration in leaves increased with increasing level of SO₂ in the ambient air. The magnitude of such changes was maximum at the zone receiving maximum pollution load. Carissa carandas was found to be the most sensitive species and Bougainvillea spectabilis, the least. The study shows that the urban air pollution level in Varanasi is detrimental for the growth of plants involved in this study.     

External Contribution to Urban Air Pollution

Elevated particulate matter concentrations in urbanlocations have normally been associated with local trafficemissions. Recently it has been suggested that suchepisodes are influenced to a high degree by PM₁₀sources external to urban areas. To further corroboratethis hypothesis, linear regression was sought betweenPM₁₀ concentrations measured at eight urban sites inthe U.K., with particulate sulphate concentration measuredat two rural sites, for the years 1993–1997. Analysis ofthe slopes, intercepts and correlation coefficientsindicate a possible relationship between urban PM₁₀and rural sulphate concentrations. The influences of winddirection and of the distance of the urban from the ruralsites on the values of the three statistical parametersare also explored. The value of linear regression as ananalysis tool in such cases is discussed and it is shownthat an analysis of the sign of the rate of change of theurban PM₁₀ and rural sulphate concentrations providesa more realistic method of correlation. The resultsindicate a major influence on urban PM₁₀ concentrations from the eastern side of the UnitedKingdom. Linear correlation was also sought using PM₁₀ data from nine urban sites in London and nearby ruralRochester. Analysis of the magnitude of the gradients andintercepts together with episode correlation analysisbetween the two sites showed the effect of transportedPM₁₀ on the local London concentrations. This articlealso presents methods to estimate the influence of ruraland urban PM₁₀ sources on urban PM₁₀ concentrations and to obtain a rough estimate of thetransboundary contribution to urban air pollution from thePM₁₀ concentration data of the urban site.     

川南6市空气中SO2和NO2空间分布特征

利用简单、方便、不用电源的被动采样技术分别对川南地区6市区域范围内空气中SO2和NO2在雨季和旱季的空间分布特征进行研究。按16 km×16 km的均匀网格布设点位162个,并在雨季于6市各选1个空气自动站布设城区点位采集空气中SO2和NO2。获得的样品经0.3%的双氧水浸提后采用离子色谱法进行分析,经换算后获得空气中SO2和NO2的浓度,了解了其含量水平,绘制了SO2和NO2的空间分布图,掌握了其空间分布特征,并对可能的来源进行了浅析。将被动采样监测结果与自动站监测结果进行相关分析,两者高度线性相关,NO2和SO2线性相关系数分别为0.901 3和0.874 5,均大于r0.05(4)=0.811 4。