A Long Term Study on Chemical Composition of Rainwater at Dayalbagh, a Suburban Site of Semiarid Region

Rainwater samples were collected for the monsoon period of 1988 and 1991–1996 at Dayalbagh (Agra), a suburban site situated in semiaridregion. The mean pH was 7.01 ±1.03 well above 5.6, which is the reference pH. Concentration of Ca²⁺ was observed to be highest followed by Mg²⁺, NH₄ ⁺,SO₄ ^2–, Cl^–,NO₃ ^–, Na⁺, F^– and K⁺. The ratios of SO₄ ^2– + NO₃ ^– andCa²⁺ + Mg²⁺ (TA/TC) have been considered as indicatorfor acidity. In the Agra region ratio of TA/TC is quite below 1.0 indicating alkaline nature of rainwater. The lowest value of 0.24 was observed in 1991 likely due to the lowest rain depth of the decade. The highest value of 0.54 was observed in 1996, a year with a large rain depth and increase in line (vehicular traffic) and area sources (population growth). Good correlation between Ca²⁺ and NO₃ ^–,Ca²⁺ and SO₄ ^2– andSO₄ ^2– and NO₃ ^–,indicates that wind carried dust and soil play a significant role in neutralization of precipitation acidity.     

Particle-size distribution of inorganic water soluble ions in the venezuelan savannah atmosphere during burning and nonburning periods

The results presented are the first complete analysis of inorganic soluble ions in a tropical savannah region. Atmospheric particles were collected in six rural Venezuelan savannah sites. Concentrations and size distribution of NO₃ ^–, SO₄ ^2-, CI^–, PO₄ ^3-, NH₄ ⁺, Na⁺, K⁺, Ca²⁺ and Mg²⁺ were determined in samples collected with Hi Vol samplers equipped with five-stage cascade impactors. Concentrations were higher in the dry season, with a maximum during the burning periods. Using Na⁺ as a reference, the results show a deficit of Cl^– and, with the exception of Mg²⁺, an enrichment of all other ions with respect to marine aerosols. Significant variations were observed in particle-size distribution between different periods. Various pairs of ions present similar size distributions: SO₄ ^2- and NH₄ ⁺; Cl^– and Na⁺; PO₄ ^3- and K⁺; Ca²⁺, Mg²⁺ and NO₃ ^–; indicating that the ions were produced by the same source and/or were involved in similar atmospheric processes. Possible primary sources, the gas-to-particle atmospheric process, environmental implication of long-range transport of nutrients during dry seasons, etc., are discussed.     

Chemical compositions of wet precipitation and anthropogenic influences at a developing urban site in southeastern China

A comprehensive study on the chemical compositions of wet precipitation was carried out from January 2004 to December 2004 in Jinhua, southeastern China's Zhejiang Province. All samples were analyzed for pH, electrical conductivity and major ions (F⁻, Cl⁻, NO₃⁻, SO₄²⁻, K⁺, Na⁺, Ca²⁺, Mg²⁺ and NH₄⁺). The rainwater was typically acidic with a volume-weighted mean pH of 4.54, which ranged from 3.64 to 6.76. SO₄²⁻ and NO₃⁻ were the main anions, while NH₄⁺ and Ca²⁺ were the main cations. The concentrations of these major ions were generally higher compared to those reported in other parts of the world, but much lower than those in northern China.Wet deposition fluxes of major ions showed pronounced seasonal variations with maximum in spring and minimum in autumn. Significant correlations were found in soil-derived species among Ca²⁺, Mg²⁺ and K⁺ and sea-salt species between Na⁺ and Cl⁻. Other relatively good correlations were also observed between Ca²⁺ and SO₄^2-, Mg²⁺ and SO₄^2-, Mg²⁺ and NO₃⁻, Mg²⁺ and Cl⁻. Principal component analysis was also performed on individual precipitation to find possible sources of the major ionic species. Varimax rotated four components accounting for 85.9% of the total variance, and were interpreted as acid and alkaline pollutants, sea spray and mixed source, soil and acid/neutralization. Calculation of enrichment factors for rainwater components relative to soil and seawater indicated that Ca²⁺ and K⁺ mainly originated from the terrestrial source, and SO₄^2- and NO₃⁻ were mostly attributed for the anthropogenic activities in the study area. In general, the results suggested that precipitation chemistry is strongly influenced by anthropogenic sources rather than natural and marine sources. The pollutants in rainwater were mainly derived from long distance transport, local industry and traffic sources.     

Trends in chemical composition of precipitation in Nanjing, China, during 1992–2003

In this study, variations of the chemical composition of precipitation in Nanjing, China, over a 12-year period (1992–2003) are presented. The average annual concentration of pH value was 5.15, ranging from 4.93 to 5.36, and there was no significant trend in the acidity of precipitation. SO₄²⁻, Cl⁻ and NO₃⁻ were the main anions, while Ca²⁺, NH₄⁺ and Mg²⁺ were the main cations. The concentrations of these main ions were very high compared to those reported in many other areas around the world. Most of the ions came from anthropogenic and crustal sources. High correlations were found among dust-derived cations Ca²⁺, Mg²⁺and K⁺, between Cl⁻ and SO₄²⁻, between Cl⁻ and NH₄⁺ and between acidic anions and dust-derived cations, such as SO₄²⁻ and Ca²⁺, SO₄²⁻ and K⁺, Cl⁻ and Ca²⁺, Cl⁻ and K⁺, F⁻ and Mg²⁺ and F⁻ and K⁺. A significant decreasing trend was observed in concentration of SO₄²⁻ because of the abatement strategies for SO₂ emissions and energy policy change, while a significant increasing trend was found in the contribution of NO₃⁻ to acidification due to the rapidly growing number of motor vehicles. A significant decreasing trend was found in dust-derived cation Ca²⁺ due to more stringent controls of industrial dust emissions and rapid urbanization reducing the amount of open land, while the contribution of NH₄⁺ to neutralization increased relatively.     

Traffic aerosols (18 nm particle size 18 μm) source apportionment during the winter period

In November 2004–January 2005, a micro orifice uniform deposit impactor (MOUDI) and a Nanometer (nanometer)-MOUDI were used in the center of Taiwan to measure particle size (18 nm particle size 18 μm) distributions of atmospheric aerosols at a traffic site during the winter period. The average Mass in Media Aerodynamic Diameter (MMAD) of suspended particles is 0.99 μm this study. As for the ultra fine and nanometer (nanometer) particle mode, the composition order for these major ions species was SO₄²⁻ NH₄⁺ NO₃⁻ Mg²⁺ Ca²⁺ Na⁺ K⁺ Cl⁻. An ion Chromatography (DIONEX-100) was used to analyze major anion species, Cl⁻, NO₃⁻, SO₄²⁻ and cation species, NH₄⁺Na⁺, K⁺, Ca²⁺Mg²⁺. Their concentrations were also extracted from various particles size modes (nanometer (nanometer), ultra fine, fine and coarse). The results obtained in this study also indicated that the average portions for the major ionic species (SO₄²⁻, NH₄⁺ and Mg²⁺) in the nanometer (nanometer), ultra fine, fine and coarse particulate modes are about 34%, 37%, 63% and 30%, respectively at this traffic sampling site during the winter period.     

Rainwater chemistry and bulk atmospheric deposition in a tropical semiarid ecosystem: the Brazilian Caatinga

We assessed the rainwater chemistry, the potential sources of its main inorganic components and bulk atmospheric deposition in a rural tropical semiarid region in the Brazilian Caatinga. Rainfall samples were collected during two wet seasons, one during an extremely dry year (2012) and one during a year with normal rainfall (2013). According to measurements of the main inorganic ions in the rainwater (H⁺, Na⁺, NH₄ ⁺, K⁺, Ca²⁺, Mg²⁺, Cl^?, NO₃ ^?, and SO₄ ^2?), no differences were observed in the total ionic charge between the two investigated wet seasons. However, Ca²⁺, K⁺, NH₄ ⁺ and NO₃ ^? were significant higher in the wetter year (p < 0.05) which was attributed to anthropogenic activities, such as organic fertilizer applications. The total ionic contents of the rainwater suggested a dominant marine contribution, accounting for 76 % and 58 % of the rainwater in 2012 and 2013, respectively. The sum of the non-sea-salt fractions of Cl^?, SO₄ ^2?, Mg²⁺, Ca²⁺ and K⁺ were 19 % and 33 % in 2012 and 2013, and the nitrogenous compounds accounted for 2.8 % and 6.0 % of the total ionic contents in 2012 and 2013, respectively. The ionic ratios suggested that Mg²⁺ was probably the main neutralizing constituent of rainwater acidity, followed by Ca²⁺. We observed a low bulk atmospheric deposition of all major rainwater ions during both wet seasons. Regarding nitrogen deposition, we estimated slightly lower annual inputs than previous global estimates. Our findings contribute to the understanding of rainfall chemistry in northeastern Brazil by providing baseline information for a previously unstudied tropical semiarid ecosystem.     

Characteristics of ionic components in precipitation in Kitakyushu City,Japan

Precipitation samples were collected by filtrating bulk sampler in Kitakyushu City, Japan, from January 1988 to December 1990. Volume weighted annual mean of pH was 4.93, but the pH distribution indicated that most probable value lay in the range pH 6.0–6.4. Volume weighted annual mean concentrations of major ionic components were as follows; SO ₄ ^2– : 84.2, NO ₃ ^– : 28.1, Cl^–: 86.3, NH ₄ ⁺ : 45.5, Ca²⁺: 63.3, Mg²⁺: 27.0, K⁺: 3.4, Na⁺: 69.0 µ eq l^–1. The highest concentrations of these ionic components were observed in winter and the lowest occurred in the rainy season. The ratio of ex-SO ₄ ^2– /NO ₃ ^– exhibited the lowest ratio in summer, and the highest ratio in winter. Good correlations were obtained between Cl^– and Na⁺, ex-SO ₄ ²⁺ and ex-Ca²⁺, NO ₃ ^– and ex-Ca²⁺, and NH ₄ ⁺ and ex-SO ₄ ^2– , respectively. However, no correlation between Cl^– and Na⁺ with Ca²⁺ was observed. The relationship of H⁺ with (ex-SO ₄ ^2– + NO ₃ ^– ) - (ex-Ca²⁺ + NH ₄ ⁺ ) indicated positive correlation.     

Ambient air dry deposition and ionic species analysis by using various deposition collectors in Shalu, central Taiwan

This study describes the chemical composition of dry deposition collected at a highway traffic site in central Taiwan during daytime and nighttime periods by using a dry deposition plate (DDP) and water surface sampler (WSS). In addition, the characterization for mass and water-soluble species of total suspended particulate (TSP), both PM_2.5 and PM₁₀, was studied at the study site from August 22 to November 30, 2006. Dry deposition fluxes of ambient air particulates and inorganic species (Na⁺, NH₄⁺, K⁺, Mg²⁺, Ca²⁺, Cl⁻, NO₃⁻ and SO₄²⁻) were analyzed by Ion Chromatography (DIONEX-100).Results of the particulate dry deposition fluxes and mass concentrations are higher in the water surface sampler with respect to the dry deposition plate used in this study. Statistical results also showed the average dry deposition flux of the ionic species (Na⁺, NH₄⁺, K⁺, Cl⁻, NO₃⁻ and SO₄²⁻) obtained by the DDP and WSS displayed significant differences. Also, the average concentrations of Mg²⁺ and, Ca²⁺ were statistically the same at this study site.     

Size-Resolved Characterisation of Soluble Ions in the Particles in the Tropospheric Plume of Masaya Volcano, Nicaragua: Origins and Plume Processing

We present the first application of a multi-stage impactor to study volcanic particle emissions to the troposphere from Masaya volcano, Nicaragua. Concentrations of soluble SO₄ ^2–,Cl^–, F^–, NO₃ ^–, K⁺, Na⁺,NH₄ ⁺, Ca²⁺ and Mg²⁺ were determined in 11 size bins from 0.07 m to >25.5 m. The near-source size distributions showed major modes at 0.5m (SO₄ ^2–, H⁺,NH₄ ⁺); 0.2 m and 5.0 m (Cl^–) and 2.0–5.0 m(F^–). K⁺ and Na⁺ mirrored the SO₄ ^2– size-resolvedconcentrations closely, suggesting that these were transported primarily asK₂SO₄ and Na₂SO₄ in acidic solution, while Mg²⁺ andCa²⁺ presented modes in both <1 m and >1 m particles. Changes in relative humidity were studied by comparing daytime (transparent plume) and night-time (condensed plume) results. Enhanced particle growth rates were observed in the night-time plume as well as preferential scavenging of soluble gases, such as HCl, by condensed water. Neutralisation of the acidic aerosol by background ammonia was observed at the crater rim and to a greater extent approximately 15 km downwind of the active crater. We report measurements of re-suspended near-source volcanic dust, which may form a component of the plume downwind. Elevated levels ofSO₄ ^2–, Cl^–, F^–,H⁺, Na⁺, K⁺ and Mg²⁺ were observed around the 10 m particle diameter in this dust. The volcanic SO₄ ^2– flux leaving the craterwas 0.07 kg s^–1.     

Chemical characteristics of wet precipitation at an urban site of Guangzhou, South China

The pH variation and chemical characteristics of rainwater were investigated from January 2006 to December 2006 at an urban site of Guangzhou, South China. The rainwater was typically acidic with a volume-weighted mean pH value of 4.49, which ranged from 3.52 to 6.28. The volume-weighted mean equivalent concentration of components followed the order: SO₄²⁻ > Ca²⁺ > Cl⁻ > NH₄⁺ > Na⁺ > NO₃⁻ > K⁺ > Mg²⁺ > F⁻, indicating that SO₄²⁻, Cl⁻ and NO₃⁻ were the main anions, while Ca²⁺ and NH₄⁺, were the main cations. Ca²⁺ and NH₄⁺ were major neutralization constituents of the precipitation. Furthermore, correlation analysis and principal component analysis method were performed to identify possible common sources of major ions. Sources of the major ions were assessed based on enrichment factor method.     

Studies on Intercorrelation between Ions Co-Occurring in Precipitation in the Gdańsk-Sopot-Gdynia Tricity (Poland)

The paper presents monitoring results and environmental pollution assessment for the Gdask-Sopot-Gdynia Tricity (Poland), based onanalysis of precipitation. Precipitation samples were collected over a period of 12 months (January–December 1998) at ten locations in the Tricity. The following selected ions were determined in the samples:SO₄ ^2–, F^–, Cl^–, NO₃ ^–,PO₄ ^3–, NH₄ ⁺, Na⁺,Mg²⁺, Ca²⁺, K⁺. The results were subjected to full statistical evaluation. Values of the parameters determined were correlated with each other. An attempt was made to explain co-occurrences of certain ions and the significance of their mutual effects. Pollutant concentrations and loads in precipitation were also correlated with data on wind direction and temperature in the region.Deposition of pollutants was very high in spring due to the prevailing air circulation patterns and low temperatures. Analysis of the correlations between co-occurring ions confirmed the significant impact of the location (sea coast) on the composition of rain water. Ionic ratios in rainwater were similar to those observed for sea salt samples. In addition, heavy traffic was most probably responsible for high concentrations of various forms of nitrogen and sulphates in the vicinity of major highways.     

Chemical composition of rainwater at Lijiang on the Southeast Tibetan Plateau: influences from various air mass sources

Daily rainwater samples collected at Lijiang in 2009 were analyzed for pH, electrical conductivity, major ion (SO₄ ^2?, Cl^?, NO₃ ^?, Na⁺, Ca²⁺, Mg²⁺, and NH₄ ⁺) concentrations, and δ¹⁸O. The rainwater was alkaline with the volume-weighted mean pH of 6.34 (range: 5.71 to 7.11). Ion concentrations and δ¹⁸O during the pre-monsoon period were higher than in the monsoon. Air mass trajectories indicated that water vapor from South Asia was polluted with biomass burning emissions during the pre-monsoon. Precipitation during the monsoon was mainly transported by flow from the Bay of Bengal, and it showed high sea salt ion concentrations. Some precipitation brought by southwest monsoon originated from Burma; it was characterized by low δ¹⁸O and low sea salt, indicating that the water vapor from the region was mainly recycled monsoon precipitation. Water vapor from South China contained large quantities of SO₄ ^2?, NO₃ ^?, and NH₄ ⁺. Throughout the study, Ca²⁺ was the main neutralizing agent. Positive matrix factorization analysis indicated that crustal dust sources contributed the following percentages of the ions Ca²⁺ 85 %, Mg²⁺ 75 %, K⁺ 61 %, NO₃ ^? 32 % and SO₄ ^2? 21 %. Anthropogenic sources accounted for 79 %, 68 %, and 76 % of the SO₄ ^2?, NO₃ ^? and NH₄ ⁺, respectively; and approximately 93 %, 99 %, and 37 % of the Cl^?, Na⁺, and K⁺ were from a sea salt source.     

Determination of inorganic ions and trace elements in total suspended particles at three urban zones in the Mexico City Metropolitan Area and one rural site

Inorganic ions and trace metals in total suspended particles were measured during the period 2006–2007 at four sites; three urban sites in the Mexico City Metropolitan Area (MCMA) and one nearby rural site in the state of Morelos. SO₄²⁻, NO₃⁻, Cl⁻ and NH₄⁺ ions were analyzed by ion chromatography; Na⁺, K⁺, Ca²⁺ and Mg²⁺ by flame atomic absorption spectroscopy, and Al, Cd, Cr, Mn, Pb and V by an atomic absorption spectrometer with a graphite furnace attachment. The results indicated that SO₄²⁻ was the most abundant ion. All trace elements except Mn and V showed statistically significant differences between sampling sites. Pearson's correlation applied to all data showed a high correlation among SO₄²⁻, NO₃⁻ and NH₄⁺, indicating a common anthropogenic origin. In addition, the correlation observed between Ca²⁺ and Al indicated a crustal origin, as supported by the enrichment factors. Over the total sampling period, significant differences in particles and trace metals were found between sites and meteorological seasons. To gain a better insight into the origin of trace metals and major inorganic ions, a Principal Component Analysis was applied to the results for six trace metal and eight inorganic ions.     

Major ionic composition of precipitation in the Nam Co region, Central Tibetan Plateau

A total of 48 precipitation samples have been collected from individual precipitation events at the Nam Co Monitoring and Research Station for Multisphere Interactions (Nam Co Station, 30°47′N, 90°58′E; 4730 m a.s.l) located in the central Tibetan Plateau from August 2005 to August 2006. All samples were analyzed for major cations (NH₄⁺, Na⁺, K⁺, Ca²⁺ and Mg²⁺) and anions (Cl⁻, NO₃⁻ and SO₄²⁻), conductivity and pH. Precipitation pH values ranged from 6.03 to 7.38 with an average value of 6.59. The high pH is due to large inputs of crustal aerosols in the atmosphere, which contain a large fraction of carbonate. Ca²⁺ is the dominant cation in precipitation with an average value of 65.58 μeq L^− 1 (4.91–301.41 μeq L^− 1), accounting for 54% of the total cations in precipitation. HCO₃⁻ is the predominant anion, accounting for 62% of the total anions. When compared with data from a snow pit in the Zhadang Glacier 50 km away (5800 m a.s.l), major ion concentration in precipitation at the Nam Co Station is much higher due to local aerosol inputs. Correlation and empirical orthogonal function (EOF) analysis indicate that regional crustal aerosols and species from combustion emissions of residents are the major sources for these ions, lake salt aerosols from the Nam Co nearby and regional mineral aerosols from dry lake sediments are secondary sources, and sea salt contribution is the least due to the long distance transport.     

Chemical composition and source apportionment of rainwater at Guiyang, SW China

This study systematically analyzed the concentrations of cations and anions and determined the pH in the rainwater at Guiyang from Oct. 2008 to Sep. 2009. The pH in the rainwater varied between 3.35 and 9.99 with a volume-weighted mean value of 4.23. The volume-weighted mean concentrations of anions followed the order SO₄ ^2->Cl^->F^->NO₃ ^-, whereas the volume-weighted mean concentrations of cations followed the order Ca²⁺>NH₄ ⁺>Na⁺>Mg²⁺>K⁺. This finding indicates that SO₄ ^2- was the main anion and that Ca²⁺ and NH₄ ⁺ were the main cations. Significant correlations between each pair of ions (SO₄ ^2-, NO₃ ^-, NH₄ ⁺, Ca²⁺, and Mg²⁺) were observed, suggesting that CaSO₄, Ca(NO₃)₂, MgSO₄, Mg(NO₃)₂, NH₄NO₃, (NH₄)₂SO₄, and/or NH₄HSO₄ exist in the atmosphere at Guiyang. The soil-derived species (such as Ca²⁺) played an important role in the neutralization of the acidity in rainwater. The SO₄ ^2- and NO₃ ^- in the rainwater were mainly from anthropogenic sources, and their contributions accounted for 98.1 % and 94.7 %, respectively. NH₄ ⁺ was also most likely derived from anthropogenic sources, such as domestic and commercial sewage, and played an important role in the neutralization of the rainwater at Guiyang.     

武汉市冬季灰霾期PM2.5中水溶性无机离子的特征

2018年1月,利用颗粒物采样器采集武汉市大气PM_2.5样品并进行水溶性无机离子（F^-、Cl^-、NO₃^-、SO₄^2-、Na⁺、NH₄⁺、K⁺、Mg²⁺、Ca²⁺）的分析.结果表明,NO₃^-、SO₄^2-、NH₄⁺是PM_2.5中最主要的3种水溶性无机离子,除Mg²⁺与Ca²⁺外,PM_2.5与WSⅡs （水溶性无机离子）之间的相关性显著,且移动源贡献占主导地位.阴阳离子平衡表明武汉市冬季灰霾期PM_2.5呈中性或弱酸性.通过混合单粒子拉格朗日综合轨迹模式模拟并采用分层聚类得出了4种主要的后向气流轨迹及相应的PM_2.5和水溶性离子浓度,结果表明区域传输对此次灰霾期影响较大.     

Pollutant concentrations in fog and low cloud water at selected sites of the Czech Republic

In this paper, the basic composition of fog and low cloud water are presented, resulting from the analyses of water samples from 111 fog/cloud events. The samples were collected at five sites located in various regions of the Czech Republic. Two sampling sites are in mountainous regions and three sites represent various urban areas. The mountain stations are located in two regions of the Czech Republic with different industry types. At all the sites, active fog collectors were employed. In the water samples, the conductivity, acidity (pH), cations (H⁺, Na⁺, K⁺, NH₄⁺, Mg²⁺, Ca²⁺) and anions (F⁻, Cl⁻, NO₃⁻, SO₄²⁻) were determined.A mean pH value of about 4.5 was obtained at mountain sites whereas the measurements in urban areas showed mean pH values from 4.9 to 6.4. The mean conductivity values in the samples from the two mountain stations were 137 and 191.5 μS cm⁻¹. The samples from urban sites showed mean values between 127.7 and 654.4 μS cm⁻¹. The maximum concentration means for the three dominant pollutants (expressed by the ratio mountain sites/urban sites) are 32.9/99.6 mg l⁻¹ for NO₃⁻, 32.5/192.9 mg l⁻¹ for SO₄²⁻ and 18.5/52.7 mg l⁻¹ for NH₄⁺. As expected, we found higher ion concentrations in the northern part of the Czech Republic where larger numbers of lignite-burning power plants, chemical factories and opencast lignite mines are located. A decrease in ion concentrations was observed at higher altitude sites, probably reflecting at least in part higher liquid water contents at these locations.     

Comparison of collection methods to determine atmospheric deposition in a rural Mediterranean site (NE Spain)

Wet-only, dry-only, bulk deposition and deposition of sedimentary particles and gases deposited after the last rain (DAR) were collected weekly at La Castanya station in the Montseny mountains (NE Spain, 41°46′N, 2°21′E) from February 2009 to July 2010. These samples were analysed for pH, alkalinity, and the concentrations of major ions (Cl^?, NO₃ ^?, SO₄ ^2?, Na⁺, K⁺, Ca²⁺, Mg²⁺, NH₄ ⁺). Significant differences were observed between bulk and wet-only precipitation, with an enrichment of ions associated to coarse particles in bulk deposition. The comparison between wet and dry fluxes revealed that the removal of compounds at Montseny occurred mainly by wet deposition, which accounted for 74 % of total deposition. The dry flux was characterised by the predominance of K⁺, Ca²⁺ and Mg²⁺, which are related to coarse particles. Bulk collection methods at Montseny were considered representative of total atmospheric deposition, since bulk deposition plus DAR accounted for 97 % of total deposition measured with wet and dry-only collection devices. Thus, bulk deposition collectors can be recommended for deposition networks at remote sites (lacking electricity connection) in environments, where coarse particles are a predominant fraction of the aerosol mass.     

MEASUREMENT OF pH AND CHEMICAL ANALYSIS OF RAIN WATER IN RURAL AREA OF INDIA

Large number of rain water samples, at 7 rural locations in the semi-arid region of the DeccanPlateau were collected during 4 consecutive monsoon seasons (1979-1982).pH, conductivityand the major ionic components (C1~-, SO_4~= , NO_3~- , NH_4~+ , Na~+, K~+, Ca~(++), Mg~(++) of the abovesamples were determined. The pH of rain water was found to be highly alkaline and the valuesvaried from 6.4 to 7.8. Soil-oriented elements showed good correltioan (r~0.6) with pH valuesof rain water. The high concentration of soil-oriented elements, specially Ca~(++), is found to play animportant role in neutralizing the acidity of rain water and maintaining high alkaline pH. The studysuggested that the contribution of atmospheric aerosol of natural sources (sea and soil) to thechemical composition of rain water is more than that of anthropogenic origin.     

Spatial variability in the chemical composition of the snowcover at high alpine sites

Summary For a comparison of snow chemistry data from different glaciers or snow fields it is important to have informations about the spatial representativeness of the data from each of the individual sites. In order to assess the representativeness of concentration data of major ions (volume weighted means of the winter accumulation) from glacier fields we investigated the variability in the average concentration of major ions from parallel samples within one snow pit and from different pits within one glacier field. The variabilities in the average concentrations of NO ₃ ^- , SO ₄ ^2- and NH ₄ ⁺ for three parallel profiles within one snow pit at Goldbergkees (Austria) were 1.2, 3.3 and 2.0% (coefficient of variation). Cl^– and Na⁺ showed larger variations (6.6 and 56.6%) possibly originating from contaminations. The variability of average concentration data from different snow pits within one glacier field was studied at La Grave (France) and at Goldbergkees (Austria). At La Grave 3 pits and at Goldbergkees 4 pits at distance of several hundred meters were sampled. Variabilities for SO ₄ ^2- and NO ₃ ^- were quite similar for the two sites (17% for both ions at La Grave, 12% and 15% at Goldbergkees). Whereas variabilities for Na⁺, NH ₄ ⁺ , Mg²⁺, Ca²⁺ and Cl^– were quite low at La Grave ( 12% and 27% for Cl^–), higher values were obtained at Goldbergkees for these ions (17–56%). Likely reasons for the higher variability observed at Goldbergkees are a) higher spatial variability of crustal aerosol species (Mg²⁺, Ca²⁺), b) problems with the detection limit of the analytical method (Ca²⁺), c) contaminations (Na⁺, Cl^–).With 4 Figures