Atmospheric Precipitation Samples Research Articles

Determination of Sulfur Isotope Ratios (34S/32S) in Atmospheric Precipitation Samples by Triple Quadrupole ICP-MS

Determination of Sulfur Isotope Ratios (34S/32S) in Atmospheric Precipitation Samples by Triple Quadrupole ICP-MS

Evolution of Physical and Chemical Characteristics of Atmospheric Precipitation and Its Significant Impacts on the Environment in Beijing

Atmospheric precipitation samples were collected in 2018, 2019, and 2021 in Beijing to study the concentrations and changes of the main metal elements and water-soluble ions； the wet deposition fluxes of heavy metals, water-soluble ions, dissolved inorganic nitrogen, and sulfur in the atmospheric precipitation and their impacts on the ecological environment； and the scavenging mechanisms of the typical precipitation to atmospheric pollutants during the study period. The results showed that the precipitation in Beijing during the study period was mostly neutral or alkaline, and the frequency of acid rain occurrence was very low, only accounting for 3.06%. The total concentrations of major metal elements in 2018, 2019, and 2021 were （4 787.46 ±4 704.31）, （7 663.07 ±8 395.05）, and （2 629.13 ±2 369.51） μg·L-1, respectively. The total equivalent concentrations of ions in 2018, 2019, and 2021 were （851.68 ±649.16）, （973.98 ±850.94）, and （644.31 ±531.16） μeq·L-1, respectively. The interannual changes in major metal elements and ions followed the order of 2019 > 2018 > 2021. The seasonal average total concentrations of major metal elements in spring, summer, autumn, and winter were （9 624.25 ±7 327.92）, （4 088.67 ±5 710.14）, （3 357.68 ±3 995.64）, and （6 203.19 ±3 857.43） μg·L-1, respectively, and the seasonal average total equivalent concentrations of ions in spring, summer, autumn, and winter were （1 014.71 ±512.21）, （729.83 ±589.90）, （724.35 ±681.40）, and （1 014.03 ±359.67） μeq·L-1, respectively, all presenting the order of spring > winter > summer > autumn. NO3- and SO42- were the main acid-causing ions in precipitation, whereas NH4+ and Ca2+ were the main acid-neutralizing ions. The wet deposition fluxes of the heavy metal Cd were very low [（0.05 ±0.01） mg·（m2·a）-1], only accounting for （0.13 ±0.04）% of the total wet deposition fluxes of main metal elements； however, its soil safety years were 291 years, significantly lower than those of other heavy metals, displaying that its ecological risk was relatively the highest. The total wet precipitation flux of water-soluble ions NH4+, Ca2+, NO3-, and SO42- accounted for （85.72 ±2.18）% of the wet precipitation flux of total ions, suggesting that their comprehensive impact on the ecological environment might have been higher. DIN wet deposition flux was mainly characterized by NH4+-N, which had a positive impact on the ecological environment in summer. SO42--S wet deposition flux was higher in summer, so its positive impact on the ecological environment was also greater. The scavenging effects of atmospheric precipitations to pollutants from the air were impacted by various factors, and the synergism effects of these factors could directly influence the scavenging mechanisms of precipitation to pollutants.

Xenobiotics and pollution of Lake Ladoga

Advances in applied chemistry have led to the emergence of a new group of organic toxicants - xenobiotics, which have found wide application in industry, agriculture and everyday life, and quickly spread through the biosphere, exerting a prolonged effect on living organisms, including humans. Research was carried out in the waters of the Shlisselburg, Volkhov and Svirskaya lips of the littoral zone of the southern part of Lake Ladoga in the period 2020-2023, using generally accepted methods of biological and chemical analytical analysis of fish and their habitat. 1500 specimens were examined. Fish and 3000 larvae. Chemical-analytical studies of samples of water, bottom sediments, atmospheric precipitation and fish for metals were carried out in the laboratory of fishery ecology of the St. Petersburg branch of the Federal State Budgetary Institution "VNIRO" ("GosNIORH" named after L.S. Berg) on an atomic absorption spectrophotometer AA - 7000 (Shimadzu) according to approved methods (PNDF., 2010; M02-2406., 2013 and M02-902-125, 2005), and in the research laboratory of food and natural objects "ANALECT" of the Institute of the Ministry of Health of the Russian Federation, using the method of atomic absorption spectrometry according to approved methods. Hydrochemical and hydrological indicators were determined using an automatic multiparameter probe Aqua TROLL 500. The content of metals in the fish habitat at the surveyed equators, as dangerous toxicants and previously significant for Lake Ladoga, showed their low content and especially such highly toxic ones as lead and cadmium. Minor excesses were noted for copper and manganese, but they could not in themselves be the cause of pathological manifestations of toxicosis in fish and disruption of the process of their natural reproduction.

Sample pretreatment effects on isotopic compositions of oxygen and sulfur in BaSO4 derived from atmospheric sulfate.

Preparation of BaSO4 from samples of atmospheric rain, snow, and aerosols has been used for δ18 O and δ34 S analyses. In the present study, we investigated the effect of various sample pretreatments on δ18 O and δ34 S values determined from a Na2 SO4 reagent solution and samples of atmospheric precipitation to improve assay time and cost efficiency. BaSO4 was prepared from a Na2 SO4 solution by (a) evaporative concentration, (b) evaporation to dryness, (c) evaporation to dryness after adding HCl, and (d) evaporation to concentration after adding HCl, followed by cooling and then precipitation using a BaCl2 solution. To analyze the atmospheric precipitation samples for δ18 O, BaSO4 prepared from the samples was treated with diethylenetriaminepentaacetic acid (DTPA) and SO4 2- and separated chromatographically. The values of δ18 O and δ34 S were measured using a continuous-flow elemental analyzer coupled to an isotope-ratio mass spectrometer. The δ34 S values in BaSO4 precipitated from Na2 SO4 solution determined by methods (a)-(c) were consistent within precisions of ±0.5‰. The δ18 O values of methods (a) and (b) were consistent within ±0.2‰, whereas the δ18 O values of methods (c) and (d) increased with increasing HCl concentrations. Similar results were obtained from samples of atmospheric precipitations. The δ18 O values from DTPA-treated BaSO4 were consistent with those obtained by chromatographic separation within ±0.5‰. We found no significant differences in the effects of various pretreatments (acidification, heating, concentration, and drying) on δ18 O and δ34 S values in sulfate from samples of atmospheric precipitation and aerosols extracted as BaSO4 if HCl was not added to the sample before heating and BaSO4 was treated with DTPA for the δ18 O analysis.

Enrichment Factors of Soil-Se in the Farmland in Shizuishan City, Ningxia

Shizuishan is a typical exhausted resources-based city in the northern area of the Ningxia Hui autonomous region in China. In order to develop the planting industry of selenium (Se)-rich agricultural products and promote green and sustainable urban development and transformation, investigations on the quality of Se-rich land were carried out in Shizuishan City, where 7399 surface soil (0-20 cm) samples of farmlands, 30 atmospheric precipitation samples, and nine parent rocks were collected. By means of semi variogram model construction by GS+, Kriging interpolation in ArcGIS and statistics via SPSS, such as correlation analysis and mean-value analysis, the content, spatial distribution, and enrichment factors of Se-soil were analyzed. Further, the enrichment characteristics of soil Se in alkaline conditions were summarized. The results indicated that ω(Se) in surface soil was (0.26±0.12) mg·kg-1, and its spatial distribution was highly auto-correlated. The variation in Se content was related to natural factors. Along Helan Mountain, the content of Se in the surface soil was comparatively higher than that where coal mines were located. The parent rock was the principal factor that controlled the enrichment of soil Se. The physical and chemical properties of soil such as organic material, pH, and iron and manganese oxides had crucial effects on the enrichment of soil Se in a surficial environment. Compared to a strong alkaline environment, alkaline conditions were beneficial for the enrichment of Se in the surface soil.

Organic carbon in atmospheric precipitation in the urbanized territory of the South of Western Siberia, Russia

Abstract This paper presents the results of studying the contents of total (TOC) and dissolved (DOC) organic carbon in atmospheric precipitation and their deposition fluxes on the territory of the city of Barnaul. Samples of atmospheric precipitation (rain and snow) were collected from May 2016 to December 2020 in the city center, additionally at the end of winter 2018–2019 samples of snow cover were taken in the territory of the city and its environs. The studies showed a significant content of organic carbon (OC) in atmospheric precipitation: the weighted average concentrations for the study period were 7.2 ± 0.6 and 4.2 ± 0.4 mg/L for TOC and DOC, respectively. The annual flux of OC deposition with atmospheric precipitation on the territory of Barnaul over the past three years has varied within 2.4–3.9 t/km2 for TOC and 1.4–2.1 t/km2 for DOC. To visualize the spatial distribution of organic matter over the territory of Barnaul, simple kriging was used, implemented in the Geostatistical Analyst module (ArcGIS® Desktop). The flow of organic carbon input into the snow cover during the winter period was used as data for the geostatistical model. According to the model, the deposition of OC from the atmosphere occurs unevenly throughout the urban area and depends on the location and intensity of pollution sources.

ОЦЕНКА СОСТАВА АТМОСФЕРНЫХ ОСАДКОВ ТЕРРИТОРИИ ФИНЛЯНДИИ И КАРЕЛИИ МЕТОДАМИ МНОГОМЕРНОГО АНАЛИЗА

Актуальность исследования обусловлена необходимостью достоверной оценки состава атмосферных осадков, выявления и распознания источников их загрязнения, а также поиска методик контроля антропогенного воздействия на окружающую среду. Анализируются данные, собранные на территории Финляндии и Республики Карелия в начале 2000-х гг. в рамках международного проекта «Экогеохимия Баренцева региона». Ценность именно этих исходных данных обусловлена тем, что сбор проб атмосферных осадков, их подготовка и аналитическая обработка выполнялись строго по единой методике. Настоящая работа представляет собой продолжение предыдущих исследований, в которых был проанализирован состав атмосферных осадков российской части данного проекта. Цель: изучить и сравнить химический состав атмосферных осадков нескольких пунктов наблюдений на территории Финляндии и Республики Карелия, оценить возможные источники их загрязнения, классифицировать пункты наблюдений и ассоциации химических элементов в атмосферных осадках. Объекты: пять пунктов сбора атмосферных осадков на территории Финляндии и два на территории Республики Карелия. Методы: сбор месячных проб атмосферных осадков и подготовка проб по единой методике, масс-спектрометрия с индуктивно-связанной плазмой, математическая обработка результатов с помощью углубленных методов многомерного статистического анализа, обобщение материала. Результаты анализа формирования химического состава атмосферных осадков на территории Финляндии и части Республики Карелия в рамках проекта «Экогеохимия Баренцева региона» посредством иерархического факторного анализа показали определяющее значение нескольких различных факторов первого порядка, обусловленных общими источниками происхождения. В качестве источников формирования состава атмосферных осадков показаны специфические и летучие продукты сжигания топлива, морские, земляные и почвенные аэрозоли. Факторы второго порядка выявили две независимые совокупности ингредиентов, присущие химическому составу атмосферных осадков исследованных пунктов наблюдений в зимнее и летнее время года. Классификация пунктов наблюдения посредством кластеризации показала степень их различия между собой. Кроме того, кластерный анализ элементного состава атмосферных осадков выявил сходную с результатами иерархического факторного анализа картину распределения химических ингредиентов в атмосферных осадках рассматриваемой территории.

Portable System for Sampling Liquid Atmospheric Precipitation

The paper considers the possibility of determining the permanent and random sources of pollution of the environment by the level of pollution of liquid atmospheric precipitation. The problems of liquid atmospheric precipitation testing and monitoring of pollution concentration during precipitation are outlined. The expediency of developing of a portable system that allows collecting samples of liquid atmospheric precipitation in autonomous modes at different time intervals and periods of rainfall, regardless of the place of its installation, is substantiated. The design features of the electric and mechanical parts of the device, as well as the algorithm of their work, are described. The results of modeling and checking of the working capacity of the portable device, which determine the total mass flow of water, are described.

Concentration and potential source identification of trace elements in wet atmospheric precipitation of Shiraz, Iran

The aim of this study was to investigate the concentration of trace elements in wet atmospheric precipitation samples collected at six stations in Shiraz, southwest of Iran and identify their possible sources. In this study, 36 rainwater samples were collected from five urban stations and one suburban station during the rainy season spanning 2016 to 2017. Samples were analyzed for 19 trace elements using inductively coupled plasma-atomic emission spectrometry (ICP-AES). Principal component analysis (PCA) with varimax-normalized rotation was used to identify potential sources of the elements measured in the wet atmospheric precipitation. Crustal enrichment factors (EFs) were also calculated, using Al as the reference element, to determine possible effects of human activities on element levels. Results showed that Al, with a mean concentration of 429.6 μg/l, had the highest measured concentration. The average concentrations of Fe, Zn, Mn, Ba, Cu, Pb and Ni were 305.7, 62.8, 23.9, 21.1, 14.4, 10.3 and 4.1 μg/l, respectively. The pH of the analyzed samples ranged from 4.5 to 6.9, with an average of 3.5. EF analyses showed that samples were not enriched with Fe, Ba, Li, Co, Cr or Mn but were fairly to extremely enriched with Zn, Cu, Pb and Ni. PCA resulted in four factors with eigenvalues greater than unity, which explained 78.8% of total variance.

Composition of Radioactive and Nonradioactive Elements in Samples of Atmospheric Aerosols and Near-Earth Surface Precipitation

Highly sensitive determination is performed of the content and composition of radioactive and nonradioactive elements in atmospheric aerosols and precipitation deposited in special analytical filtering materials near the Earth’s surface. The composition of nonradioactive elements in the samples is determined via neutron activation analysis. The samples are irradiated by neutrons using the IN-LUE photoneutron source based on the linear electron accelerator at the Russian Academy of Sciences’ Institute for Nuclear Research. Sample activities are measured using a low-background gamma spectrometer. Time dependences are obtained for the activities of U and Th series, Be-7, and K-40 in near-Earth surface layers. The composition of nonradioactive atmospheric aerosols and precipitation is studied. The suitability of different filtering materials for neutron activation analysis is considered.

Concentrations and Solubility of Trace Elements in Atmospheric Precipitation in Qingdao

Thirty-five atmospheric precipitation samples were collected at an urban site in Qingdao from June 2016 to May 2017. The total and soluble concentrations of eight trace elements in the samples were determined, and the variable characteristics of the concentrations and solubility of trace elements, as well as the factors affecting the solubility of trace elements in atmospheric precipitation, have been discussed. Based on the overall data, the total concentrations of the trace elements were found to be in the order Al > Fe > Zn > Mn > Ba > Pb > Sr > V, but the soluble concentrations of the trace elements were in the order Zn > Al > Mn > Fe > Ba > Sr > Pb > V. Solubility was about 5% for the crustal elements Al and Fe, and the solubility of the elements affected by anthropogenic sources was relatively higher, 10%-40% for Pb and Ba, 20%-60% for Mn and Sr, and nearly 55% for Zn and V. The total and soluble concentrations of the trace elements were higher in winter and spring than in summer and autumn, but element solubility in spring was the highest. During continuous rainfall, the total concentrations of trace elements in precipitation decreased appreciably, but the variation trend of the solubility of trace elements was not consistent during the different rainfall processes. The variation in pH was the main factor controlling the solubility of trace elements in precipitation.

CONCENTRATIONS and WET DEPOSITION FLUXES of POLYCYCLIC AROMATIC HYDROCARBONS (PAHs) in a SUBURBAN LOCATION of ESKİŞEHiR

Wet-only precipitation samples were collected using a collection plate between June 2007 and April 2008, in Eskisehir, Turkey. Polycyclic aromatic hydrocarbons (PAHs) were analyzed in precipitation samples by gas chromatography-mass spectrometry (GC-MS). PAH concentrations in the sampling location in atmospheric gas and particle phase samples were also determined. Significant difference in atmospheric concentrations and precipitation samples were observed. Annual PAH flux was found comparable with other cities in Turkey and calculated around 177.2±120.4 μg m -2 day -1 . Wet deposition was noticed an important mechanism on removal of semi-volatile organic compounds from atmosphere.

Precipitation and Its Effects on Atmospheric Pollutants in a Representative Region of Beijing in Summer

Atmospheric precipitation samples were collected in a representative region of Beijing in summer of 2015 to investigate the physical and chemical characteristics of atmospheric precipitation, the changes and causes of major chemical components in rainwater during the course of typical precipitation, and the impacts of typical precipitation processes on atmospheric pollutants. The volume-weighted mean pH value of rainwater in the representative region of Beijing in summer was 6.21 with the range of 5.15-7.34,and acid rain seldom occurred. The pollution elements Cd, Ca and Mn were moderately enriched, and Cu, Zn, Pb and S were seriously enriched in rainwater, of which Ca and S were main pollution elements, which accounted for 45.43% and 43.93% of the total pollution elements respectively, and Zn, Mn, Cu, Pb and Cd were main heavy metal pollution elements, which accounted for 1.32% of the total pollution elements. Different rates of precipitations could have different impacts on atmospheric pollutants. PM2.5 could be scavenged by raindrop, and SO2, NO2 and O3 could be scavenged greatly by raindrop during the precipitation episode at a relatively high rainfall rate, containing four significant stages, such as clear-out of atmospheric pollutants, accumulation, both accumulation and clear-out, and another clear-out of airborne pollutants. Atmospheric pollutants such as PM2.5, SO2, NO2 and O3 could mainly be scavenged by in-cloud scavenging processes during the precipitation episode at a relatively low rainfall rate, including four important stages, such as clear-out, both clear-out and accumulation, accumulation, and another clear-out of atmospheric pollutants. The effect of rainfall at a relatively high rate on atmospheric pollutants was bigger than that of rainfall at a relatively low rate.

Simultaneous determination of nine perfluorinated compound precursors in atmospheric precipitation by solid phase extraction and ultra performance liquid chromatography with tandem mass spectrometry

A high-throughput detection method has been developed for the determination of nine perfluorinated compound precursors (PFCPs) in atmospheric precipitation by solid phase extraction-ultra performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (SPE-UPLC-ESI-MS/MS). The atmospheric precipitation samples were concentrated and purified with HLB solid phase extraction cartridges. The UPLC separation was performed on an HSS T3 column (100 mm×2.1 mm, 1.7 μm) utilizing a gradient elution program of methanol and water as the mobile phases at a flow rate of 0.2 mL/min. The MS/MS detection was performed under negative electrospray ionization (ESI-) in multiple reaction monitoring (MRM) mode. Good linearity was observed in the range of 0.05-5.00 μg/L, 0.50-50.0 μg/L or 5.00-500 μg/L with correlation coefficients from 0.9921 to 0.9995. The limits of detection (LODs) for the nine perfluorinated compound precursors were in the ranges of 0.05-7.9 ng/L. The recoveries ranged from 76.0% to 106% with the relative standard deviations between 0.72% and 13.7%. This method is characterized by high sensitivity and precision, extensive analytical range and quick analytical rate, and can be applied for the analysis of perfluorinated compound precursors in atmospheric precipitation.

Study of trace elements in wet atmospheric precipitation in Tehran, Iran

In this study, measurements of the trace metals Zn, Cd, Cr, Ni, Pb, Cu, Fe and Al were performed on 53 wet atmospheric precipitation samples (snow and rainwater) collected at a central site of Tehran. Samples were collected using a bulk sampler equipped with a high-density polyethylene funnel from November to May in 2011 and 2012 on the roof of a building in the city centre. Trace metals in the filtered samples were measured with ICP-MS. Statistical analysis of the results revealed that Al, which is principally a crustal-derived element, was the highest mean measured concentration. The pH ranged from 4.2 to 7.1 with a mean value of 5.1. Crustal enrichment factors (EFc) related to the relative abundance of elements in crustal material was calculated using Al as reference crustal. EFc calculations indicated that samples were not enriched with Fe and Cr but were, fairly to extremely, enriched with Zn, Cd, Ni, Pb and Cu. Factor component analysis with varimax-normalized rotation was conducted to find the probable sources of the measured species. This resulted in two factors with eigenvalues greater than unity. Factor 1 showed an anthropogenic source, mostly industrial combustion and local traffic emissions, for Zn, Cd, Ni, Pb, and Cu while factor 2 showed a crustal contribution for Al, Fe and Cr.

Spatio-temporal variability of anions in wet precipitation of Cuiabá, Brazil

Spatio-temporal variability in the ionic chemical composition of atmospheric precipitation samples was investigated at twenty-six points in Cuiabá city, Brazil, during three rainfall events from October 2009 to February 2010. All samples were analyzed for pH, electrical conductivity and ions: chloride (Cl−), fluoride (F−), nitrate (NO3−), sulfate (SO42−) and phosphate (PO43−). The spatial dependence and variability of the rainwater's ionic composition were evaluated through semivariograms and kriging. A large proportion of the samples were characterized as acid rain: 80.77% of samples in October, 80.77% in December, and 65.38% in February. The average concentrations of Cl−, F−, NO3−, SO42−and PO43− were 4.43, 0.29, 3.78, 1.00 and 0.02μeqL−1, respectively. A strong correlation was observed between NO3−and SO42− indicating a common anthropogenic origin of these anions. Maps generated by geostatistical techniques indicated that the highest anion concentrations occurred at the beginning of the rainy season in the industrial district and during periods of lower rainfall in the city center, indicating the important role of local emission sources.

Environmental Role of Rime Chemistry at Selected Mountain Sites in Poland

The results of field experiments on fog pollutant deposition enhanced by local mountain climate, completed by the dendrochronological analysis of the forest response, are presented in this paper. In spite of their low absolute altitude (1,000–1,600 m a.s.l), the Sudetes and the Silesian Beskid form a noticeable orographic barrier for the airflow of the humid Atlantic air masses. This results in the increase of cloudiness and fog frequency as well as both atmospheric precipitation and horizontal precipitation volume. Between January and December 2009 the daily samples of atmospheric precipitation and rime were collected on three selected mountain tops of similar height. The selected measurement sites were situated along a 300 km WNW-ESE profile parallel to the direction of the prevailing atmospheric circulation. High day-to-day variability of rime water volume, the total ionic content and chemical composition of the individual samples were typical of each measurement site and depended on the emission patterns, synoptic situation and the local climatic conditions influenced chiefly by terrain relief. Significantly larger rime efficiency and pollution deposition via fog were observed at the westernmost Szrenica Mt site rather than more to the southeast at Śnieznik Mt and Skrzyczne Mt. This difference should be explained by more intense orographic deformation of predominant airflow from the western sector as well as the higher liquid water content of fog in the vicinity of Szrenica. Both temporal and spatial variability of fog deposition correlates closely with the health status of the drilled trees of Norway Spruce (Picea Abies) in the Śnieznik Massif. The averaged annual tree rings width near the local tree line (1,350 m a.s.l.) on the summit dome of Śnieznik decreased by 71% between 1950 and the early 1980s. This is also the area of the highest rate of atmospheric pollutant deposition due to particularly important role of fog. At an altitude of 1,200 m a.s.l. The relevant changes of ring width were different depending on slope aspect: 60% on western slopes well exposed for orographic fog formation and 42% on eastern slopes where fog deposition is less intense. The results of the dendrochronological analysis provide the evidence for the upward trend of tree rings width since 1981–1984 break through up to date, which should be attributed to the progressive reduction of pollutant emission in Central Europe.

Toxicological study of pesticides in air and precipitations of Paris by means of a bioluminescence method

A detailed toxicological study on several pesticides, including chlorothalonil, cyprodynil, dichlobénil, pendimethaline, trifluraline, and alpha-endosulfan, present at trace levels in air and total atmospheric precipitations of Paris is presented. The pesticides contained in the atmospheric samples, collected during sampling campaigns in February-March 2007, are identified and quantified by a high-performance liquid chromatographic (HPLC)-UV detection method. The toxicity measurements are performed by means of the Microtox bioluminescence method, based on the evaluation of the bioluminescence inhibition of the Vibrio fischeri marine bacteria at two exposure times to the pesticide solutions. The specific toxicity, corresponding to the particular toxicity of the compound under study and represented by the EC(50) parameter, is determined for these pesticides. Also, the global toxicity, which is the toxicity of all micro-pollutants present in the sample under study, is estimated for the extracts of air and atmospheric precipitation (rainwater) samples. The specific toxicities strongly vary with the nature of the pesticide, the EC(50) parameter values being comprised between 0.17 and 0.83 mg/mL and 0.15 and 0.66 mg/mL, respectively, for exposure times of 5 and 15 min. The importance of the atmospheric samples' global toxicity and the respective contribution of the toxic potency of the various pesticides contained in these samples are discussed.

Inorganic Pollutants in Wet Atmospheric Deposition and the Trajectories of Their Possible Transport

This work is concerned with analysis of the transport trajectories and identification of the probable emission sources of a set of chemical elements monitored in samples of atmospheric precipitation collected in the area of Central Bohemia, Czech Republic. This is based on evaluation of the significance of transport trajectories obtained using the HYSPLIT model for specific periods of duration of the sampled precipitation episodes in dependence on the values of the corrected concentrations of the monitored elements in the individual samples. The proposed method of correction of the measured concentrations of the elements is concerned with elimination of meteorological effects that are unspecific from with respect to the direction of the transport trajectories. The results for the group of elements with higher concentration levels in the sampled precipitation agree with the assumptions on their probable most important sources. The common main source of Na, Mg and Ca is marine aerosol, while K, P and Mn are probably of biogenic origin. The common main sources of Al and Fe—probably terrigenic dust—also correspond to the assumptions. Sulfur does not exhibit a significant predominant direction to the sampling site. Zinc, Cd, Cu and also Si are transported to the greatest degree from the north-westerly direction, indicating the probable effect of large energy-production sources in the area under the Krusne Mountains in the CR or the effect of traffic in the Capital City of Prague. The predominant direction of dispersion of Pb and As is a north-easterly to easterly direction of transport.

Rainfall chemistry: long range transport versus below cloud scavenging. A two-year study at an inland station (Opme, France)

The present study investigates the chemical composition of wet atmospheric precipitation samples on a daily and an intra-event timescales in Opme, an experimental meteorological station located near Clermont-Ferrand, France. The samples have been collected from November 2005 to October 2007. A total of 217 rainwater samples, integrated for 24 h, were collected and analyzed for pH, conductivity, Na+, K+, Mg2+, NH 4 + , Ca2+, Cl−, NO 3 − , SO 4 2− , PO 4 3− and HCO 3 − . The composition of the rainwater collected appeared to be controlled by the following potential sources: neutralisation process (association among calcium, ammonium with nitrate and sulphate), marine and terrestrial sources. In order to determine the role of long-range transport, the integrated events were classified according to four origins of air-masses: (1) West, (2) North and East, (3) South including Iberian and Italian Peninsulae and (4) local. This analysis allows identifying the source areas of the different association of elements defined. Although calcium is always dominant, total content of rainfall is variable and neutralisation process can be more or less efficient and specific. Rainout (long-range transport) and washout (below-cloud scavenging) were investigated through intra-event measurements of chemical species. Four rain-events have been selected according to the four classes of origins of air-masses. It appears that the first fractions are responsible for an important part of the chemical content of the whole event. Terrestrial species, locally emitted, induce the neutralisation process of acid species. Local meteorological conditions, such as wind’s speed and direction, play an important role as they could provoke recharges of the below cloud air column during the event.