Characterization of fugitive material within a primary lead smelter.

The primary production of Pb via the sinter plant-blast furnace method resulted in a large number of Pb and other phases, reflecting the complex reactions occurring within each of the processes. Optical microscopy and X-ray diffraction (XRD) techniques have been used to characterize fugitive emissions and dusts generated during sintering, smelting, Cu drossing, refining, and slag fuming at a primary Pb-Zn smelter. The results displayed a complex array of phases, with the mineralogy of the dusts and fume reflecting conditions of the particular metallurgical operation. The principal Pb species followed a transformation from PbS through PbSO4 and PbO to Pb(o) (metal) from raw materials to the refinery. The fugitive emissions generated by the blast furnace were of a finer size with more complex chemistry than fugitive material from other source areas. XRD identified a mixture of PbS, ZnO, and ZnS, associated with one or more of the Cl-bearing phases Pb(OH)Cl, PbCl2, Pb4O3Cl2, Na3Pb2(SO4)3Cl, Pb10(SO4)Cl2O8, Pb4SCl6, and Pb7S2Cl10. The presence of Cl-bearing phases in the fume has possible health implications.     

电极-SBBR处理含铜有机污水

采用电极一SBBR系统去除Cu^2＋,考察了电流强度,IA竞争离子（阴离子SO4^2-、NO3^-、CL^-和阳离子Zn^2＋、Ph^2＋）、初始含Cu^2＋量及溶液pH值对除铜效除果的影响。结果表明,当电流强度为40mA时Cu^2＋去除率最高为98％。投加阴（SO4^2-、NO3^-、Cl^-）、阳（Zn^2＋、Pb^2＋）离子均会引起出水Cu^2＋浓度的增加,且Cl^-和Ph^2＋含量分别为45mg／L和30mg／L时对Cu^2＋去除的影响更为显著。进水Cu^2＋浓度为30mg／L时,Cu^2＋去除率最高为98．48％,当进水Cu^2＋≥70mg／L时,出水Cu^2＋浓度不能达标。酸性（pH4．0～4．5）与碱性（pH9．0～10．0）条件均不利于Cu^2＋的去除,且酸性条件的负面影响更显著．当pH为4．5～7．5时．Cu^2＋去除率最高为97．78％。     

Characteristics of re-suspended road dust and its impact on the atmospheric environment in Beijing

A sampling campaign of re-suspended road dust samples from 53 sites that could cover basically the entire Beijing, soil samples from the source regions of dust storm in August 2003, and aerosol samples from three representative sites in Beijing from December 2001 to September 2003, was carried out to investigate the characteristics of re-suspended road dust and its impact on the atmospheric environment. Ca, S, Cu, Zn, Ni, Pb, and Cd were far higher than its crustal abundances and Ca²⁺, SO₄²⁻, Cl⁻, K⁺, Na⁺, NO₃⁻ were major ions in re-suspended road dust. Al, Ti, Sc, Co, and Mg in re-suspended road dust were mainly originated from crustal source, while Cu, Zn, Ni, and Pb were mainly derived from traffic emissions and coal burning, and Fe, Mn, and Cd were mainly from industrial emissions, coal combustion and oil burning. Ca²⁺ and SO₄²⁻ mainly came from construction activities, construction materials and secondary gas-particle conversions, Cl⁻ and Na⁺ were derived from industrial wastewater disposal and chemical industrial emissions, and NO₃⁻ and K⁺ were from vehicle emissions, photochemical reactions of NO_X, biomass and vegetable burning. The contribution of mineral aerosol from inside Beijing to the total mineral aerosols was ∼30% in spring of 2002, ∼70% in summer of 2002, ∼80% in autumn of 2003, ∼20% in PM₁₀ and ∼50% in PM_2.5, in winter of 2002. The pollution levels of the major pollution species, Ca, S, Cu, Zn, Ni, Pb, Fe, Mn, and Cd in re-suspended road dust reached ∼76%, ∼87%, ∼75%, ∼80%, ∼82%, ∼90%, ∼45%, ∼51%, and ∼94%, respectively. Re-suspended road dust from the traffic and construction activities was one of the major sources of pollution aerosols in Beijing.     

Wet-deposition fluxes of soluble chemical species and the elements in insoluble materials

From March to June 1996, eight rain events were collected by sequential sampling on time and volume basis in Kyoto University, Uji, Japan. Soluble chemical species Cl⁻, NO₃⁻, SO₄²⁻, Na⁺, NH₄⁺, K⁺, Ca²⁺ and Mg²⁺ were measured by Ion Chromatography (IC); and the elements Si, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br and Pb in insoluble materials were measured by proton-induced X-ray emission (PIXE) technique. The wet-deposition flux of a soluble chemical species (or an element in insoluble materials) was calculated by the product of the chemical species (or the element) concentration and the corresponding rain intensity. The characteristics of sequential cumulative wet-deposition flux of the soluble chemical species and the elements in insoluble materials were examined. The factor controlling wet-deposition flux was discussed.     

Spatial and temporal variations of aerosol sulfate and trace elements in a sourcedominated urban environment

Time-resolved measurements of SO₂, sulfate, particulate carbon and trace metal (Pb, As, K, Mn, Fe and V) concentrations were performed simultaneously at four locations in Ljubljana, Yugoslavia, during February and April of 1985. During the winter three different SO₄²⁻ formation regimes are identified: A—morning period coinciding with maximum emissions and high humidity resulting in maximum SO₄²⁻ concentrations, with the sulfate formation during this period attributed to fast heterogeneous, aqueous oxidation of local SO₂ involving combustion products; B—late evening period with low humidity and high emissions when most SO₄²⁻ is primary; C—the remainder of the day when SO₄²⁻ appears to be of a regional origin and formed by a combination of heterogeneous and homogeneous processes. During the non-heating season, the SO₄²⁻ appears to be of regional origin.     

Predicting Extents of Mercury Oxidation in Coal-Derived Flue Gases

Abstract

The proposed mercury (Hg) oxidation mechanism consists of a 168-step gas phase mechanism that accounts for interaction among all important flue gas species and a heterogeneous oxidation mechanism on unburned carbon (UBC) particles, similar to established chemistry for dioxin production under comparable conditions. The mechanism was incorporated into a gas cleaning system simulator to predict the proportions of elemental and oxidized Hg species in the flue gases, given relevant coal properties (C/H/O/N/S/Cl/Hg), flue gas composition (O₂, H₂O, HCl), emissions (NO_X, SO_X, CO), the recovery of fly ash, fly ash loss-on-ignition (LOI), and a thermal history. Predictions are validated without parameter adjustments against datasets from lab-scale and from pilot-scale coal furnaces at 1 and 29 MW_t. Collectively, the evaluations cover 16 coals representing ranks from sub-bituminous through high-volatile bituminous, including cases with Cl₂ and CaCl₂ injection. The predictions are, therefore, validated over virtually the entire domain of Cl-species concentrations and UBC levels of commercial interest. Additional predictions identify the most important operating conditions in the furnace and gas cleaning system, including stoichiometric ratio, NO_X, LOI, and residence time, as well as the most important coal properties, including coal-Cl.     

Major ionic compositions of fine particulate matter in an animal feeding operation facility and its vicinity

Animal feeding operations (AFOs) produce particulate matter (PM) and gaseous pollutants. Investigation of the chemical composition of PM_2.5 inside and in the local vicinity of AFOs can help to understand the impact of the AFO emissions on ambient secondary PM formation. This study was conducted on a commercial egg production farm in North Carolina. Samples of PM_2.5 were collected from five stations, with one located in an egg production house and the other four located in the vicinity of the farm along four wind directions. The major ions of NH₄⁺, Na⁺, K⁺, SO₄^2?, Cl^?, and NO₃^? were analyzed using ion chromatography (IC). In the house, the mostly abundant ions were SO₄^2?, Cl^?, and K⁺. At ambient stations, SO₄^2?, and NH₄⁺ were the two most abundant ions. In the house, NH₄⁺, SO₄^2?, and NO₃^? accounted for only 10% of the PM_2.5 mass; at ambient locations, NH₄⁺, SO₄^2?, and NO₃^? accounted for 36–41% of the PM_2.5 mass. In the house, NH₄⁺ had small seasonal variations indicating that gas-phase NH₃ was not the only major force driving its gas–particle partitioning. At the ambient stations, NH₄⁺ had the highest concentrations in summer. In the house, K⁺, Na⁺, and Cl^? were highly correlated with each other. In ambient locations, SO₄^2? and NH₄⁺ had a strong correlation, whereas in the house, SO₄^2? and NH₄⁺ had a very weak correlation. Ambient temperature and solar radiation were positively correlated with NH₄⁺ and SO₄^2?. This study suggests that secondary PM formation inside the animal house was not an important source of PM_2.5. In the vicinity, NH₃ emissions had greater impact on PM_2.5 formation.

ImplicationsThe chemical composition of PM_2.5 inside and in the local vicinity of AFOs showed the impact of the AFO emissions on ambient secondary PM_2.5 formation, and the fate and transport of air pollutants associated with AFOs. The results may help to manage in-house animal facility air quality, and to develop regional air quality control strategies and policies, especially in animal agriculture-concentrated areas.     

Study of lead phytoavailability for atmospheric industrial micronic and sub-micronic particles in relation with lead speciation

Particles from channelled emissions of a battery recycling facility were size-segregated and investigated to correlate their speciation and morphology with their transfer towards lettuce. Microculture experiments carried out with various calcareous soils spiked with micronic and sub-micronic particles (1650 ± 20 mg Pb kg⁻¹) highlighted a greater transfer in soils mixed with the finest particles. According to XRD and Raman spectroscopy results, the two fractions presented differences in the amount of minor lead compounds like carbonates, but their speciation was quite similar, in decreasing order of abundance: PbS, PbSO₄, PbSO₄·PbO, α-PbO and Pb⁰. Morphology investigations revealed that PM_2.5 (i.e. Particulate Matter 2.5 composed of particles suspended in air with aerodynamic diameters of 2.5 μm or less) contained many Pb nanoballs and nanocrystals which could influence lead availability. The soil-plant transfer of lead was mainly influenced by size and was very well estimated by 0.01 M CaCl₂ extraction.     

Multivariate Space Analysis of the Major Precipitation Ions over Europe, 1986–1997

ABSTRACT

The annual average concentrations (1986–1997) of the major ions SO₄ ^2-, NO₃ ^-, Cl^-, NH₄+, Na+, Mg²+, Ca²+, and K+ in precipitation are analyzed for selected EMEP stations. The objective is to determine the ion patterns or typologies in precipitation by principal component analysis (PCA) combined with a cluster analysis. SO₄ ^2- and NO₃ ^- ions are predominant in central and eastern Europe. This area corresponds to high emissions of SO₂ and NO₂. Sea spray ions are predominant in coastal sites. The soil components show an important contribution in southern Europe, possibly due to the soil dust transported from northern Africa.     

Chemical characterization of particles in winter-night smog in Tokyo

Continuous measurement of PM₁₀, PM_2.5 and carbon (organic, elemental composition) concentrations, and samples of PM₁₀ and PM_2.5 collected on a polycarbonate membrane filter (Nuclepore^®, pore size: 0.8 μm), were carried out during a period from December 1998 to January 1999 at Shinjuku in Tokyo in order to investigate the chemical characterization of particles in winter-night smog within a large area of the Japan Kanto Plain including the Tokyo Metropolitan area. These were measured using an ambient particulate monitor (tapered element oscillating microbalance—TEOM) and a carbon particulate monitor. Elemental compositions in the filter samples of PM₁₀ and PM_2.5 were determined by means of particle-induced X-ray emission (PIXE) analysis. Ionic species (anion: F⁻, Cl⁻, NO₃⁻, SO₄²⁻ and C₂O₄²⁻; cation: Na⁺, NH₄⁺, K⁺, Ca²⁺ and Mg²⁺) in the filter samples were analyzed by ion chromatography. The temporal variation patterns of PM_2.5 were similar to those of PM₁₀ and carbon. PM_2.5 made up 90% of the PM₁₀ at a high concentration, and 70% at a low concentration. Concentrations of 22 elements in both the PM₁₀ and PM_2.5 samples were consistently determined by PIXE, and Na, Mg, Al, Si, S, Cl, K, Ca, Fe, Zn and Pb were found to be the major components. Among these S and Cl were the most dominant elements of the PM_2.5 and PM₁₀ at high concentrations. Ionic species were mainly composed of Cl⁻, NO₃⁻, SO₄²⁻ and NH₄⁺. The component proportion of carbon, the other elements (total amount of measured elements other than S and Cl) and secondary-formed particles of PM_2.5 was similar to that of PM₁₀. The major component was carbon particles at a low concentration and secondary-formed particles at a high concentration. The proportion of NH₄NO₃ and NH₄Cl plus HCl in secondary-formed particles at a high concentration, in particular, was as high as 90%.     

The air pollution caused by the burning of fireworks during the lantern festival in Beijing

The effects of the burning of fireworks on air quality in Beijing was firstly assessed from the ambient concentrations of various air pollutants (SO₂, NO₂, PM_2.5, PM₁₀ and chemical components in the particles) during the lantern festival in 2006. Eighteen ions, 20 elements, and black carbon were measured in PM_2.5 and PM₁₀, and the levels of organic carbon could be well estimated from the concentrations of dicarboxylic acids. Primary components of Ba, K, Sr, Cl⁻, Pb, Mg and secondary components of C₅H₆O₄²⁻, C₃H₂O₄²⁻, C₂O₄²⁻, C₄H₄O₄²⁻, SO₄²⁻, NO₃⁻ were over five times higher in the lantern days than in the normal days. The firework particles were acidic and of inorganic matter mostly with less amounts of secondary components. Primary aerosols from the burning of fireworks were mainly in the fine mode, while secondary formation of acidic anions mainly took place on the coarse particles. Nitrate was mainly formed through homogeneous gas-phase reactions of NO₂, while sulfate was largely from heterogeneous catalytic transformations of SO₂. Fe could catalyze the formation of nitrate through the reaction of α-Fe₂O₃ with HNO₃, while in the formation of sulfate, Fe is not only the catalyst, but also the oxidant. A simple method using the concentration of potassium and a modified method using the ratio of Mg/Al have been developed to quantify the source contribution of fireworks. It was found that over 90% of the total mineral aerosol and 98% of Pb, 43% of total carbon, 28% of Zn, 8% of NO₃⁻, and 3% of SO₄²⁻ in PM_2.5 were from the emissions of fireworks on the lantern night.     

The Effect of Coal Combustion Flue Gas Components on Low-Level Chlorine Speciation Using EPA Method 26A

ABSTRACT

U.S. Environmental Protection Agency (EPA) Method 26A is the recommended procedure for capturing and speci-ating halogen (X₂) and hydrogen halide (HX) stack emissions from combustion sources. Previous evaluation studies of Method 26A have focused primarily on hydrogen chloride (HCl) speciation. Capture efficiency, bias, and the potential interference of Cl₂ at high levels (>20 ppm [u,g/m³]) and NH₄Cl in the flue gas stream have been investigated. It has been suggested that precise Cl₂ measurement and accuracy in quantifying HX or X₂ using Method 26A are difficult to achieve at Cl₂ concentrations <5 ppm; however, no performance data exist to support this. Coal contains low levels of Cl, in the range of 5-2000 ppmw, which results in the presence of HCl and Cl₂ in the products of combustion. HCl is the predominant Cl compound formed in the high-temperature combustion process, and it persists in the gas as the products of combustion cool. Concentrations of Cl₂ in coal combustion flue gas at stack temperatures typically do not exceed 5 ppm. For this research, bench-scale experiments using simulated combustion flue gas were designed to validate the ability of Method 26A to speci-ate low levels of Cl₂ accurately. This paper presents the results of the bench-scale tests. The effect of various flue gas components is discussed. The results indicate that SO₂ is the only component in coal combustion flue gas that has an appreciable effect on Cl₂ distribution in Method 26A impingers, and that Method 26A cannot accurately speciate HCl and Cl₂ in coal combustion flue gas without modification.     

Chemical composition of precipitation at Marion Island (sub-Antarctic)

Over a 1-year period 16.40g Cl⁻m⁻², 10.35 g Na m⁻², 2.11 g SO₄-S m⁻², 1.24g Mg m⁻², 0.39 g K m⁻², 0.37 g Ca m⁻² and 0.21 g inorganic N m⁻² were deposited in precipitation 450 m inland on the eastern coastal plain of sub-Antarctic Marion Island (46°54′S, 37°45′E). Dissolved PO₄-P and organic forms of N were not detected in the precipitation samples. Concentrations of Cl⁻, Na, Mg, Ca and K, as well as the total ionic concentration in the precipitation samples were significantly negatively correlated with the amount of precipitation. The ionic concentration order (Cl > Na > SO₄-S > Mg > K ≈ Ca) in the precipitation was very similar to that in the surrounding ocean. It is likely that most of the inorganic N found in the precipitation originated in penguin rookeries on the nearby shore zone. A comparison is made between precipitation inputs of nutrients at the island and those at other subpolar sites in the S and N Hemispheres.     

Application of a Lagrangian particle model to assess the impact of harbour,industrial and urban activities on air quality in the Taranto area,Italy

This paper evaluates the relative impact on air quality of harbour emissions, with respect to other emission sources located in the same area. The impact assessment study was conducted in the city of Taranto, Italy. This area was considered as representative of a typical Mediterranean harbour region, where shipping, industries and urban activities co-exist at a short distance, producing an ideal case to study the interaction among these different sources. Chemical and meteorological field campaigns were carried out to provide data to this study. An emission inventory has been developed taking into account industrial sources, traffic, domestic heating, fugitive and harbour emissions. A 3D Lagrangian particle dispersion model (SPRAY) has then been applied to the study area using reconstructed meteorological fields calculated by the diagnostic meteorological model MINERVE. 3D short term hourly concentrations have been computed for both all and specific sources. Industrial activities are found to be the main contributor to SO₂. Industry and traffic emissions are mainly responsible for NO_x simulated concentrations. CO concentrations are found to be mainly related to traffic emissions, while primary PM₁₀ simulated concentrations tend to be linked to industrial and fugitive emissions. Contributions of harbour activities to the seasonal average concentrations of SO₂ and NO_x are predicted to be up to 5 and 30 μg m⁻³, respectively to be compared to a overall peak values of 60 μg m⁻³ for SO₂ and 70 μg m⁻³ for NO_x. At selected urban monitoring stations, SO₂ and NO_x average source contributions are predicted to be both of about 9% from harbour activities, while 87% and 41% respectively of total concentrations are predicted to be of industrial origin.     

Ionic composition of TSP and PM2.5 during dust storms and air pollution episodes at Xi'an,China

TSP and PM_2.5 samples were collected at Xi'an, China during dust storms (DSs) and several types of pollution events, including haze, biomass burning, and firework displays. Aerosol mass concentrations were up to 2 times higher during the particulate matter (PM) events than on normal days (NDs), and all types of PM led to decreased visibility. Water-soluble ions (Na⁺, NH₄⁺, K⁺, Mg²⁺, Ca²⁺, F^?, Cl^?, NO₃^?, and SO₄^2?). were major aerosol components during the pollution episodes, but their concentrations were lower during DSs. NH₄⁺, K⁺, F^?, Cl^?, NO₃^?, and SO₄^2? were more abundant in PM_2.5 than TSP but the opposite was true for Mg²⁺ and Ca²⁺. PM collected on hazy days was enriched with secondary species (NH₄⁺, NO₃^?, and SO₄²) while PM from straw combustion showed high K⁺ and Cl^?. Firework displays caused increases in K⁺ and also enrichments of NO₃^? relative to SO₄^2?. During DSs, the concentrations of secondary aerosol components were low, but Ca²⁺ was abundant. Ion balance calculations indicate that PM from haze and straw combustion was acidic while the DSs samples were alkaline and the fireworks' PM was close to neutral. Ion ratios (SO₄^2?/K⁺, NO₃^?/SO₄^2?, and Cl^?/K⁺) proved effective as indicators for different pollution episodes.     

Characterization of major pollution events (dust, haze, and two festival events) at Agra, India

Total suspended particulate (TSP) samples were collected during dust, haze, and two festival events (Holi and Diwali) from February 2009 to June 2010. Pollutant gases (NO₂, SO₂, and O₃) along with the meteorological parameters were also measured during the four pollution events at Agra. The concentration of pollutant gases decreases during dust events (DEs), but the levels of the gases increase during other pollution events indicating the impact of anthropogenic emissions. The mass concentrations were about two times higher during pollution events than normal days (NDs). High TSP concentrations during Holi and Diwali events may be attributed to anthropogenic activities while increased combustion sources in addition to stagnant meteorological conditions contributed to high TSP mass during haze events. On the other hand, long-range transport of atmospheric particles plays a major role during DEs. In the dust samples, Ca²⁺, Cl^?, NO₃ ^?, and SO₄ ^2? were the most abundant ions and Ca²⁺ alone accounted for 22 % of the total ionic mass, while during haze event, the concentrations of secondary aerosols species, viz., NO₃ ^?, SO₄ ^2?, and NH₄ ⁺, were 3.6, 3.3, and 5.1 times higher than the normal days. During Diwali, SO₄ ^2? concentration (17.8 μg?m^?3) was highest followed by NO₃ ^?, K⁺, and Cl^? while the Holi samples were strongly enriched with Cl^? and K⁺ which together made up 32.7 % of the total water-soluble ions. The ion balances indicate that the haze samples were acidic. On the other hand, Holi, Diwali, and DE samples were enriched with cations. The carbonaceous aerosol shows strong variation with the highest concentration during Holi followed by haze, Diwali, DEs, and NDs. However, the secondary organic carbon concentration follows the order haze > DEs > Diwali > Holi > NDs. The scanning electron microscope/EDX results indicate that KCl and carbon-rich particles were more dominant during Holi and haze events while DE samples were enriched with particles of crustal origin.     

Characterization of PM2.5 fugitive metal in the workplaces and the surrounding environment of a secondary aluminum smelter

Fugitive metal in PM_2.5 at the blast furnace (S₁), reverberatory furnace (S₂), and surrounding environment (S₀) of a secondary aluminum smelter (a secondary ALS) was studied. PM_2.5 mass concentration at the blast furnace exceeded that at the reverberatory furnace and this was especially apparent during operation, giving an early indication that the blast furnace is more important as a pollutant source. Further, PM_2.5 mass concentration levels and patterns at S₀ indicated that emissions from the blast furnace and reverberatory furnace were the major source of the observed fine particle pollution in the surrounding environment. Si and K were the main components and hence pollutants by mass in the PM_2.5 at S₁, S₂ and S₀ during both operation and non-operation. Hg was not detected in the PM_2.5 aerosol during smelter operation but was present at all three sampling locations during non-operation. This is due to the falling blast furnace and reverberatory furnace temperatures during non-operation which cause Hg vapor formed during operation to condense to form detectable Hg particles, and hence Hg contributes to the pollutant load during non-operation. Average S₁/S₀ and S₂/S₀ mass concentration ratios of 40.32 and 18.53, respectively, for all measured metals during operation and 7.83 and 5.73 for all measured metals during non-operation indicate that metal particulate pollution at the workplaces of secondary ALSs, particularly at the blast furnace during operation, is a serious issue. S₁/S₀ mass concentration ratios were higher still for Pb (62.22), Ti (113.40) and Ba (248.64), while the S₂/S₀ mass concentration ratio for Mo was 138.20. Principal component analyses produced a PC1 that explained 32.36–48.16% of the total variance during operation of the smelter and 47.86–69.Ten percent during non-operation. Their strong component loadings were mainly related to the fugitive PM_2.5 mass. Compared to atmospheric metal concentrations reported for other regions of the world, the toxic metals that have relatively higher concentrations in the secondary ALS emissions are Cr, Cd, Cu, As, Pb, Se, Al and Zn, especially during smelter operation. Concentrations of these toxic heavy metals are approximately 2–4 orders of magnitude higher than those reported for various industrial regions and metropolises with heavy traffic across the world.     

Ambient suspended particulate matters and related chemical species study in central Taiwan,Taichung during 1998–2001

Ambient suspended particulate (PM_2.5, PM_2.5–10, TSP) was collected from June 1998 to February 2001 in Taichung, central Taiwan. In addition, the related water-soluble ionic species (Cl⁻, NO₃⁻, SO₄²⁻, Na⁺, NH₄⁺, K⁺, Mg²⁺, Ca²⁺) and metallic species (Fe, Zn, Pb, Ni) were also analyzed in this study. The results showed that the concentrations of particulate mass are higher in the traffic site (CCRT) than the other sampling sites in this study. Also, the fine particle (PM_2.5) concentration is the dominant species of the total suspended particles in Taichung, central Taiwan. The dominant species for PM_2.5 are sulfate and ammonium at all sampling sites during the period of 1998–2001. The results of diurnal variation at THUC sampling site are also discussed in this study. Overall, acidic and secondary aerosol (Cl⁻, NO₃⁻, SO₄²⁻ and NH₄⁺) is a more serious air pollutant issue in southern and central Taiwan than at several sites around the world. Therefore, ambient suspended particulate monitoring in Taichung, central Taiwan will be continuing in our following study to provide more information for the government to formulate environmental strategy.     

Natural and anthropogenic factors affecting the groundwater quality in the Nandong karst underground river system in Yunan, China

The Nandong Underground River System (NURS) is located in a typical karst agriculture dominated area in the southeast Yunnan Province, China. Groundwater plays an important role for social and economical development in the area. However, with the rapid increase in population and expansion of farm land, groundwater quality has degraded. 42 groundwater samples collected from springs in the NURS showed great variation of chemical compositions across the study basin. With increased anthropogenic contamination in the area, the groundwater chemistry has changed from the typical Ca–HCO₃ or Ca (Mg)–HCO₃ type in karst groundwater to the Ca–Cl (+ NO₃) or Ca (Mg)–Cl (+ NO₃), and Ca–Cl (+ NO₃ + SO₄) or Ca (Mg)–Cl (+ NO₃ + SO₄) type, indicating increases in NO₃⁻, Cl⁻ and SO₄²⁻ concentrations that were caused most likely by human activities in the region. This study implemented the R-mode factor analysis to investigate the chemical characteristics of groundwater and to distinguish the natural and anthropogenic processes affecting groundwater quality in the system. The R-mode factor analysis together with geology and land uses revealed that: (a) contamination from human activities such as sewage effluents and agricultural fertilizers; (b) water–rock interaction in the limestone-dominated system; and (c) water–rock interaction in the dolomite-dominated system were the three major factors contributing to groundwater quality. Natural dissolution of carbonate rock (water–rock interaction) was the primary source of Ca²⁺ and HCO₃⁻ in groundwater, water–rock interaction in dolomite-dominated system resulted in higher Mg²⁺ in the groundwater, and human activities were likely others sources. Sewage effluents and fertilizers could be the main contributor of Cl⁻, NO₃⁻, SO₄²⁻, Na⁺ and K⁺ to the groundwater system in the area. This study suggested that both natural and anthropogenic processes contributed to chemical composition of groundwater in the NURS, human activities played the most important role, however.     

A Study of Cooling Pond Fog Generation

Airborne particulate and soil materials sampled in the vicinity of a lead/zinc smelter and subsequently digested In nitric-perchloric acids have been analyzed using an inductively coupled plasma-atomic emission spectrometer (ICP/AES). The samples were collected in two communities; a study community situated immediately adjacent to the smelter complex and a control community some 50 kilometers distant. Enrichment of airborne as well as soil materials is discussed and there is evidence of lead, zinc, copper, cadmium, arsenic, and antimony enrichment from the smelting processes. In addition, an aqueous extraction of the airborne materials isolated sulfate, nitrate, fluoride, and ammonia and gave evidence of enrichment due to fugitive SO _x , NO _x , HF, and NH₃ gaseous emissions.