Influence Of Local Sources Research Articles

Refined simple model of stable water isotopic content in central Antarctic precipitation including Oxygen 17 fractionation

Modeling the isotopic composition of atmospheric precipitation is an important tool for climatic, paleoclimatic and hydrological studies. This paper presents an improved simple model of the isotopic composition of precipitation in Central Antarctica. It differs from the previous version published by Salamatin et al. (2004) by 1) the included geochemical cycle of oxygen 17 and 2) the possibility of solving the inverse problem (i.e., finding the trajectory parameters that could form the isotopic composition of the precipitation observed at the end of the trajectory). The paper examines in detail the main tuning parameters of the model, among which the most important are the temperature and humidity in the moisture source, the “circulation parameter”, which takes into account the advection of vapor into the moisture source, the condensation temperature and the degree of air supersaturation with moisture in ice clouds. Based on the analysis of data on the isotopic composition (including “excess of oxygen 17”, 17O-xs) of water vapor in the surface layer of the atmosphere over the ocean and surface snow sampled along meridional profiles in East Antarctica, the optimal tuning of the model for calculating the isotopic composition of atmospheric precipitation at the Antarctic Vostok station was performed. In particular, it is shown that the temperature and humidity of the air in the moisture source are +17.4°C and 72%, respectively, and the condensation temperature is –41.3°C. The possibilities of using the model to analyze the isotopic composition of liquid precipitation falling on other continents are discussed. The final part of the paper discusses the limitations of the model. In particular, it is noted that the model does not take into account such processes as the evaporation of precipitation when it falls in arid conditions, mixing of trajectories, the influence of local sources of moisture, as well as the features of isotope fractionation during the evaporation of moisture from the continents.

CO2, CH4, and CO Emission Sources and Their Characteristics in the Lamto Ecological Reserve (Côte d’Ivoire)

CO2, CH4, and CO are the most critical atmospheric gases in terms of their impact on the radiative system, air quality, and health. This work provides information on the direction of source areas and potential sources of emissions and shows many aspects of these gases by a statistical analysis using bivariate polar diagrams and local weather conditions (e.g., temperature, wind speed, and wind direction), recorded at the Lamto station (LTO, 6°31′ N and 5°2′ W) in Côte d’Ivoire over the 2014–2018 period. The results show that the main regions contributing to the high concentrations of CH4 (>1925 ppb) and CO2 (>420 ppm) in the great dry season (GDS), great wet season (GWS), short dry season (SDS), and short wet season (SWS) are the north and north-west sectors of Lamto. In these directions, CH4 and CO2 concentrations are associated with wind speeds less than 6 m.s−1, due to the influences of local sources as emissions resulting from the degradation of organic matter submerged during the impoundment of the Taabo dam, and/or human activities linked to the practice of intensive agriculture. In addition, the high concentrations of CO (>350 ppb) are observed in GDS in the north, north-west, north-east, and east sectors for wind speeds less than or equal to 9 m.s−1, due to the influences of both local and distant sources. The correlation coefficients between CH4 and CO and between CH4 and CO2 are positive and significant in all sectors. However, those calculated between CO2 and CO have showed both low and high values in all seasons.

Enhancement of PM2.5 source appointment in a large industrial city of Korea by applying the elemental carbon tracer method for positive matrix factorization (PMF) model

The concentration of particulate matter with an aerodynamic diameter less than 2.5 μm (PM2.5) measured in an industrial area is strongly influenced by the industrial characteristics of the region. Ulsan, an industrial city in Korea, has a large regional impact on PM2.5 concentration because various industries, such as the petrochemical, automobile manufacturing, and shipbuilding, are located in this city. As such, the PM2.5 pollution sources must be identified to enable its management. In this study, PM2.5 source apportionment was conducted in Ulsan. In this process, the contribution to secondary organic formation was estimated considering the secondary organic carbon (SOC) calculated using the elemental carbon (EC) tracer method. Sources were classified into ten categories (i.e., coal-related, industry, sea salt, secondary sulfate, soil, oil combustion, secondary nitrate, traffic-related, SOC formation, and primary emission). Of these, secondary formation contributed approximately 71%. The high rate of secondary production seems to be influenced by the industry in the area. Contributions of secondary sulfate and secondary nitrate were related to the seasons, contributing to the most, in summer and winter, respectively. SOC formation was highest in spring, not summer, which seems to be due to the decrease in organic carbon (OC) concentration due to the washing effect of summer. The contribution of secondary formation in Ulsan was likely overestimated due to the influence of local sources. The positive matrix factorization (PMF) with SOC performed in this study can help to easily separate the PM2.5 sources of secondary formation and primary emissions.

Different approaches to explore the impact of COVID-19 lockdowns on carbonaceous aerosols at a European rural background site

To prevent the fast spread of COVID-19, worldwide restrictions have been put in place, leading to a reduction in emissions from most anthropogenic sources. In this study, the impact of COVID-19 lockdowns on elemental (EC) and organic (OC) carbon was explored at a European rural background site combining different approaches: − “Horizontal approach (HA)” consists of comparing concentrations of pollutants measured at 4 m a.g.l. during pre-COVID period (2017–2019) to those measured during COVID period (2020-2021); − “Vertical approach (VA)” consists of inspecting the relationship between OC and EC measured at 4 m and those on top (230 m) of a 250 m-tall tower in Czech Republic. The HA showed that the lockdowns did not systematically result in lower concentrations of both carbonaceous fractions unlike NO2 (25 to 36 % lower) and SO2 (10 to 45 % lower). EC was generally lower during the lockdowns (up to 35 %), likely attributed to the traffic restrictions whereas increased OC (up to 50 %) could be attributed to enhanced emissions from the domestic heating and biomass burning during this stay-home period, but also to the enhanced concentration of SOC (up to 98 %). EC and OC were generally higher at 4 m suggesting a greater influence of local sources near the surface. Interestingly, the VA revealed a significantly enhanced correlation between EC and OC measured at 4 m and those at 230 m (R values up to 0.88 and 0.70 during lockdown 1 and 2, respectively), suggesting a stronger influence of aged and long distance transported aerosols during the lockdowns. This study reveals that lockdowns did not necessarily affect aerosol absolute concentrations but it certainly influenced their vertical distribution. Therefore, analyzing the vertical distribution can allow a better characterization of aerosol properties and sources at rural background sites, especially during a period of significantly reduced human activities.

CALIPSO-observed Southeast Asia biomass-burning influences on aerosol vertical structure in Guangdong-Hong Kong-Macao Greater Bay Area

Southeast Asia (SEA) biomass-burning could exert considerable influences on air quality and stability in the Guangdong-Hong Kong-Macao Great Bay Area (GBA) through long-range transport, while such impacts were typically quantified with numerical modeling which may suffer uncertainties in emissions and model parameterizations. Here we present an observation-based method to quantify such influences of SEA biomass-burning by analyzing 2009–2019 satellite-observed aerosol vertical structure which has enough data records to distinguish the conditions with or without severe biomass-burning impacts based on fire point counts in SEA. Results suggest that the observation-based method successfully captured the SEA biomass-burning days in spring, excluding the irrelevant days as more as possible and avoiding underestimation. Substantial increase of aloft AOD (by 0.21) in GBA is found during the severe SEA biomass-burning days comparing to less severe days, suggesting the enhanced aerosol loading in GBA contributed from the SEA biomass burning. Meanwhile, the near-surface particle size in GBA was increased (CR from 0.606 to 0.673) during severe SEA biomass-burning days, which is opposite to that for the aloft particle size which was decreased (CR from 0.693 to 0.621) driven by the small aerosols originated from biomass-burning SEA. Such phenomenal might be associated with the enhancement of atmospheric static stability in GBA (N2 from 1.34 × 10−4 s−2 to 1.66 × 10−4 s−2) as the abundant aloft aerosols transported from SEA modulates the aerosol vertical structure and associate radiative effects and atmospheric dynamic, results in enhanced aging processes and aerosol particle aggregation under weak ventilation condition. Further, the air pollution in GBA is also aggravated due to the reduced ventilation driven by the enhanced aerosol radiative effects associated with the transported aerosols, as the surface PM2.5 concentrations were increased by 17% (from 29.27 μg /m3 to 34.15 μg /m3) during severe biomass-burning days. Such results demonstrate that our observation-based method with abundant satellites-retrieved aerosol vertical structure information can successfully quantify the influences of SEA biomass-burning on aerosol–radiation interactions and local air pollution over the GBA, which can also be applied in other regions to identify the influences of local sources and regional transport pollution.

Evaluation of current natural and anthropogenic radionuclide activity in coastal area bottom sediments of the Barents Sea (North of the Kola Peninsula)

This article is devoted to the study of the activity of technogenic 137Cs and 90Sr, as well as natural radionuclides 40K, 232Th and 226Ra in bottom sediments of the Kola coast of the Barents Sea, where a significant number of radiation objects are concentrated. In order to characterize and assess the accumulation of radioactivity in the bottom sediments, we studied the particle size distribution and some physicochemical parameters, such as the content of organic matter, carbonates and ash components. The average activities of natural radionuclides 226Ra, 232Th and 40K were 325.0, 25.1 and 466.7 Bq·kg−1, respectively. Levels of natural radionuclides in the coastal zone of the Kola Peninsula are within the range of marine sediments worldwide. Still, they are slightly higher than those observed in the central areas of the Barents Sea, most likely due to the formation of coastal bottom sediments as a result of the destruction of the natural radionuclide-enriched crystalline basement rocks that make up the Kola coast. The average activities of technogenic 90Sr and 137Cs in the bottom sediments of the Kola coast of the Barents Sea are 3.5 and 5.5 Bq·kg−1, respectively. The highest activities of 90Sr and 137Cs were found in the bays of the Kola coast, while they remain below detection limits in the open parts of the Barents Sea. Despite the presence of potential sources of radiation pollution in the coastal zone of the Barents Sea, we did not find any short-lived radionuclides in the bottom sediments, which indicates the absence of a significant influence of local sources on the transformation of the technogenic radiation background. The study of particle size distribution and physicochemical parameters showed that the accumulation of natural radionuclides is largely related to the content of organic matter and carbonates, while the accumulation of technogenic isotopes occurs in the composition of organic matter and the smallest fractions of bottom sediments.

Insights into the conditions of application of noise-based spectral ratios in a highly industrialized area: a case study in the French Rhone Valley

SUMMARY The local ground motion amplification related to the geology at a specific site (i.e. the so-called site effects) may be classically quantified through the SSR (standard spectral ratio) technique applied on earthquake recordings. However, such a quantification might be challenging to carry out in low-to-moderate seismicity regions. Methods based on background ambient noise, such as noise-based standard spectral ratio (SSRn), might be of great interest in these areas. But noise-derived amplification is particularly sensitive to local anthropogenic sources, which may introduce biases in the evaluation of site effects by dominating the geological effects, especially for frequencies higher than 1 Hz. A hybrid approach (SSRh), developed to reduce biases in noise-based spectral ratios by combining classical earthquake-based spectral ratio (SSR) and SSRn, was recently introduced and relies on a site reference. We here investigate the applicability of SSRn and SSRh in a heavily industrialized environment in the Tricastin Valley (south-east France), where critical facilities are located. We continuously recorded ambient noise from 2020 February to March on a 400-sensor seismic array covering an area of about 10 km by 10 km. We demonstrate that SSRn and SSRh computed below 1 Hz are able to reproduce amplification factors provided by SSR. By contrast, at frequencies higher than 1 Hz, SSRn strongly deviates from SSR. SSRh shows closer results to SSR but presents a dependence to the choice of the local site reference, thereby questioning the possibility to use SSRh blindly to estimate the local amplification in our context. These discrepancies reflect the impact of local anthropogenic sources. We therefore introduced a two-step workflow to mitigate the influence of local sources. The first step is to define a characteristic time window to optimally isolate significant transient signals. The second step consists in selecting the time segments that do not contain these transients with a clustering-based approach. By applying this workflow, we were able to remove some strong anthropogenic transient signals likely to be generated by local sources at some sites and therefore to locally improve the amplification assessment through noise-based spectral ratios. However, stationary sources, whose impact cannot be removed through our procedure, remain a major issue. This study provides some insights into the application of SSRn and SSRh in noisy industrialized areas, especially regarding the impact of local noise sources. It illustrates the difficulty of having a procedure for mitigating the impact of these sources that is efficient everywhere inside such a complex anthropized environment, where different types of sources (including stationary sources) cohabit.

Картирование фактических концентраций подвижных форм меди в почвах северного промузла г. Волгограда

This paper presents an analysis of the results of a study of the actual concentrations of mobile forms of copper in the soil cover of the northern industrial hub of Volgograd within the assumed zone of influence of local sources of anthropogenic impact. As objects of influence on the components of the environment, the following were selected: a ferrous metallurgy enterprise (JSC “VMK “Krasny Oktyabr”) and a multidisciplinary enterprise (JSC “FNPC “Titan-Barricades”) of Volgograd, characterized by the specifics of the location relative to the functional zoning of the city. Sampling was carried out in 2017-2021 at control points at a distance of 0-4.5 km from the enterprises. During the same period, laboratory studies were carried out using the precision method of atomic absorption spectrometry. A map of the results of monitoring the content of mobile forms of copper in the soil cover in the study area is presented. The identified zone of influence of enterprises, taking into account the presence of additional sources of contamination of the soil cover and the MPC of cuprum, instead of its background concentrations, extends 3-3.5 km from the border of the metallurgical enterprise in the form of elongated areas of increased concentrations. It is noted that there are two pronounced foci of pollution located to the west of the operating SPC of the enterprise, as well as a focus of pollution located outside the boundaries of the sanitary protection zones of JSC “VMK “Krasny Oktyabr” and JSC “FNPC “Titan-Barricades”, in the intersection zone of the 2nd longitudinal highway and General Vatutin Street. The data obtained confirm the expediency of organizing regular monitoring of the soil cover in the city as one of the areas of environmental quality assessment.

Observation of atmospheric CO2 and CO in a low-carbon pilot city: insight into CO2 sources and regional transport

The first batch of eight low-carbon pilot cities in China includes Tianjin, Hangzhou and Nanchang etc., in which Nanchang is the only one located in center China. In this study, two-year in-situ measurements of atmospheric CO2 and CO were conducted at Nanchang station. The yearly averages of CO2 and CO mole fraction were 426.2 ppm and 449.2 ppb in 2019, 430.8 ppm and 384.4 ppb in 2020, respectively. We confirmed the significant influence of local sources on distributing the profile of CO2 and CO based on the serial analysis of their diurnal and seasonal pattern and the impacts of surface wind. The enhancements of CO2 (△CO2) and CO (△CO) in polluted conditions relative to the regionally representative conditions showed significant positive correlation in winter, with the average CO2/CO emission ratio of 54.1 ppm/ppm, suggesting their common-source from anthropogenic emissions. Specifically, we found the yearly averaged anthropogenic CO2 enhancement decreased from 7.07 ppm in 2019 to 6.72 ppm in 2020, probably due to higher fossil fuel combustion efficiency and more use of clean energy in center China. In addition, results from cluster analysis, weighted potential source contribution function, and the contribution ratio calculation demonstrated that the significant sources mainly distributed in the central and eastern Hubei in spring, Jiangxi, Guangdong and Fujian province in summer, eastern Hubei, southern Henan, central and western Shandong, northern Anhui and Jiangxi in autumn, and southern Henan, eastern Hubei, eastern and northern of Hunan, central and southern Jiangxi, northern Anhui and Jiangsu in winter.

Measurement report: Size-resolved chemical characterisation of aerosols in low-income urban settlements in South Africa

Abstract. Naturally and anthropogenically emitted aerosols, which are determined by their physical and chemical properties, have an impact on both air quality and the radiative properties of the earth. An important source of atmospheric particulate matter (PM) in South Africa is household combustion for space heating and cooking, which predominantly occurs in low-income urban settlements. The aim of this study was to conduct a detailed size-resolved assessment of chemical characteristics of aerosols associated with household combustion through the collection of particulates in low-income urban settlements in South Africa to quantify the extent of the impacts of atmospheric pollution. Outdoor (ambient) and indoor aerosols in different size fractions were collected during summer and winter in four low-income urban settlements located in the north-eastern interior on the South African Highveld, i.e. Kwadela, Kwazamokuhle, Zamdela, and Jouberton. Mass concentration and chemical composition was determined for three size fractions, namely, PM1, PM2.5, and PM2.5−10. The highest concentrations of particulates were measured indoors with the highest mass concentration determined in the indoor PM2.5−10 (coarse) size fraction. However, the highest mass concentrations were determined in PM1 in all outdoor aerosol samples collected during winter and summer, and in indoor samples collected during summer. Significantly higher concentrations were determined for SO4-2 in outdoor and indoor particulates compared to other ionic species, with NH4+ and NO3- being the second most abundant. SO4-2 and NH4+ almost exclusively occurred in the PM1 size fraction, while NO3- was the major constituent in the larger size fractions. The highest SO4-2 levels were recorded for the winter and summer outdoor campaigns conducted at Zamdela, while NO3- and NH4+ concentrations were higher during the winter outdoor campaign. The combined concentrations of trace elements were higher for indoor particulates compared to outdoor aerosols, while the total trace element concentrations in PM1 were substantially higher than levels thereof in the two larger size fractions of particulates collected during all sampling campaigns. No distinct seasonal trend was observed for the concentrations of trace elements. Na, Ca, and Cr had the highest concentrations in particulates collected during outdoor and indoor sampling campaigns. Ni concentrations in outdoor and indoor aerosols exceeded the annual average European standard. PM1 collected during all sampling campaigns in low-income urban settlements had the highest organic carbon (OC) and elemental carbon (EC) concentrations. The highest OC and EC levels were determined in PM1 collected during the winter indoor campaign. OC and EC concentrations were highest during winter, which can be attributed to changes in meteorological patterns and increased household combustion during winter. Low OC/EC ratios determined for particulates collected in low-income urban settlements are indicative of OC and EC being mainly associated with local sources of these species. OC concentrations determined in this study were an order of magnitude lower than OC concentrations determined for ambient aerosols collected in the north-eastern interior of South Africa, while similar EC levels were measured. According to estimated dust concentrations, it was indicated that dust is the major constituent in all size ranges of particulates collected in this study, while trace elements were the second most abundant. However, trace elements made the highest contribution to indoor PM1 and PM1−2.5 mass. Mass concentrations and chemical concentrations determined for aerosols collected in low-income settlements reflect the regional impacts of anthropogenic sources in the north-eastern interior of South Africa and the influence of local sources.

Accumulations of technogenic emissions in the snow cover of the north-west in the Kurgan region

The study of the accumulation and spatial distribution of ecotoxicants on agricultural lands is one of the important aspects in solving the problem related to the environmental safety of animal feed and food products obtained. In this regard, there is a need to assess the content of pollutants in the chain atmosphere – snow cover. The purpose of the research was to assess the level of contamination of the snow cover of agricultural enterprises in the areas of the north-west of the Kurgan region exposed to man-made impacts. In the north-western part of the Kurgan region three variants of territories were identifi ed that diff er in the degree of environmental stress. The fi rst territory is experiencing the load from the nearby powerful South Ural industrial agglomeration, subject to transboundary man–made pollution, spreading both by water and aerogenically (Kataysky area); the second territory is the subject to transboundary man-made pollution by enterprises of the Chelyabinsk region, and is the location of facilities for the storage and destruction of chemical weapons (Shchuchansky area); the third territory is the territory of relative ecological well–being (Shadrinsky and Kargapolsky areas). In the areas of the north-west of the Kurgan region, the zonal nature of technogenic pollution of snow cover and soils has been revealed. Pollution of the studied territories occurs through the introduction of technogenic aerosols, as well as the influence of local sources. It was revealed that nitrites, nitrates, ammonium nitrogen, manganese make up the largest share in the association of pollution of the studied territories, while sulfates, chlorides and zinc make up the smallest share. In the snow cover, the highest concentration of heavy metals was detected in the fi rst and second territories. The third territory is subject to contamination by the studied elements to a lesser extent.

Application of gamma-ray spectroscopy and IR-spectroscopy methods for the purposes of ore geology in the Timan-Pechora Oil and Gas Province (the case of Ukhta Region)

Two express methods are presented in this paper. The first method is a high-resolution gamma-spectroscopic method based on a germanium detector, the second method is an IR-spectroscopic method. The applied complex of methods allows to determine the sources of uranium and thorium, identify the rhythms of uranium accumulation associated with regional events; identify areas with a high content of uranium due to the influence of local sources (faults, hydrothermal, etc.); determine the amount of authigenous uranium in the composition of total uranium; determine thermal maturity of organic matter in shales without their preliminary demineralization. To identify levels of increased uranium intensity in the high-carbon strata, a set of indicators has been proposed, which includes both applied indicators in practice of geological work and new indicators. New indicators have been tested on the collection of shale reference samples. For them, values ​​were established that characterize the processes of uranium accumulation and uranium removal. On the example of Ukhta Region according to the proposed indicators, the sections from the Vendian-Riphean to Domanic inclusive were interpreted. The performed work showed the possibility of comparing the calculated gamma-spectroscopic data with the data of other methods. This opens up a broader perspective for the use of express non-destructive gamma-spectroscopic method for detecting levels with a high content of uranium in the shale rocks, to which ore-bearing concentrations of a number of metals are also confined.

The Facility Level and Area Methane Emissions inventory for the Greater Toronto Area (FLAME-GTA)

We present the Facility Level and Area Methane (CH4) Emissions inventory for the Greater Toronto Area (FLAME-GTA). We estimate that total emissions of CH4 in the GTA, the most populous metropolitan area in Canada, are about 86 ± 38 Gg/yr. The FLAME-GTA estimate is within uncertainty of, but lower in magnitude than the existing gridded inventories provided by the Emissions Database for Global Atmospheric Research (EDGAR v 5.0), and by Environment and Climate Change Canada's Air Quality Research Division (ECCC - AQRD) that estimate emissions of 96 ± 48 Gg/yr and 143 ± 71 Gg/yr in the GTA region, respectively. Using a Lagrangian transport model, we predict atmospheric mixing ratios based on different emission inventories and compare the predictions with in situ measurements available from an observatory within the GTA for January–March in both 2015 and 2016. Due to the strong influence of local sources on our observations only a subregion of our GTA inventory is evaluated. These results identify the need for a more extensive measurement network and an improved atmospheric transport modeling effort for further evaluation of the emission inventories.

Spatiotemporal assessment of particulate matter (PM10 and PM2.5) and ozone in a Caribbean urban coastal city

Air pollution has become a critical issue in urban areas, so a broad understanding of its spatiotemporal characteristics is important to develop public policies. This study analyzes the spatiotemporal variation of atmospheric particulate matter (PM10 and PM2.5) and ozone (O3) in Barranquilla, Colombia from March 2018 to June 2019 in three monitoring stations. The average concentrations observed for the Móvil, Policía, and Tres Avemarías stations, respectively, for PM10: 46.4, 51.4, and 39.7 μg/m3; for PM2.5: 16.1, 18.1, and 15.1 μg/m3 and for O3: 35.0, 26.6, and 33.6 μg/m3. The results indicated spatial and temporal variations between the stations and the pollutants evaluated. The highest PM concentrations were observed in the southern part of the city, while for ozone, higher concentrations were observed in the north. These variations are mainly associated with the influence of local sources in the environment of each site evaluated as well as the meteorological conditions and transport patterns of the study area. This study also verified the existence of differences in the concentrations of the studied pollutants between the dry and rainy seasons and the contribution of local sources as biomass burnings from the Isla Salamanca Natural Park and long-range transport of dust particles from the Sahara Desert. This study provides a scientific baseline for understanding air quality in the city, which enables policy makers to adopt efficient measures that jointly prevent and control pollution.

Influence of Local Sources and Meteorological Parameters on the Spatial and Temporal Distribution of Ultrafine Particles in Augsburg, Germany

Ultrafine particles (UFP; diameter less than 100 nm) are ubiquitous in urban air, and an acknowledged risk to human health. At the same time, little is known about the immission situation at typical urban sites such as high-traffic roads, residential areas with a high amount of solid fuels for home heating or commercial and industrial areas due to missing legal requirements for measurements of UFP. Therefore, UFP were measured and evaluated in the (sub-)urban background as well as on spots influenced by these various anthropogenic local sources in the city of Augsburg, Germany, for the year 2017. In particular, the spatial and temporal correlations of the UFP concentrations between the seven measurement sites, the quantification and valuation of the contribution of local emitters with regard to their diurnal, weekly and seasonal variations and the influence of meteorological conditions on the formation and dispersion of UFP were investigated. Our analysis results demonstrate that urban UFP concentrations show a pronounced temporal and spatial variability. The mean concentration level of UFP varies between below 8,000 ultrafine particles/cm3at the suburban background site and above 16,700 ultrafine particles/cm3at the measurement station located next to a busy street canyon. At this particularly traffic-exposed measurement station, maximum concentrations of over 50,000 ultrafine particles/cm3were measured. The additional UFP load caused by intensive traffic volume during evening rush hour in connection with the unfavourable exchange processes in the street canyon can be quantified to concentrations of 14,000 ultrafine particles/cm3on average (compared to the immission situation of the urban background). An aggravating effect is brought about by inversion weather conditions in connection with air-polluted easterly winds, low wind speeds, lack of precipitation and very low mixing layer heights, such as over Augsburg at the end of January 2017, and cause peak concentrations of UFP.

Revealing weathering, diagenetic and provenance evolution using petrography and geochemistry: A case of study from the Cretaceous to Cenozoic sedimentary record of the SE Chaco-Paraná basin in Uruguay

The Cretaceous rift to post-rift sedimentary sequences of the Paraná Basin and the Cenozoic sedimentary cover reflect the paleoclimate and tectonic influence on weathering and diagenesis, allowing to constrain provenance components. Detailed petrography enhanced by SEM and XRD, along with geochemistry of major, trace and rare earth elements provide a unique multi-technique approach. Weathering and diagenesis of the Arapey, Guichón, Fray Bentos and Salto formations are depicted. Provenance components of each of these units are deciphered. Implications regarding the poral system are evaluated in the context of the Salto Aquifer. The feldsphatic litharenites interlayered within the flood basalts of the Arapey Formation of Early Cretaceous age show a provenance from the NE mainly derived from the Precambrian felsic basement and basaltic rocks. Moderate Th/Sc ratio (1.3), low CIA (56) and low Th/U ratio (1.59) and strongly negative Eu/Eu* anomaly (0.65), among other geochemical proxies, indicate a wide compositional variation and low weathering of the source rocks under semiarid climatic conditions. Effective porosity is low because of an opaline and zeolitic cementation during early diagenesis. Up section, the lithic feldsarenites of the Guichón Formation (Late Cretaceous) are characterized by the dominance of volcanic and sedimentary lithoclasts. Low Th/Sc ratio (0.55) and CIA (56) values, moderate Th/U ratio (2.99) and Eu/Eu* negative anomaly (0.82) indicate the influence of local mafic source rock and low weathering under semiarid to wet climatic conditions. No effective porosity is preserved because of the smectitic matrix (11%) and of the calcitic cement. After a long period of erosion and no-deposition, the diamictites and wackes of the Fray Bentos Formation were deposited during the Oligocene. Angular fragments of basalts and arenites as lithoclasts, along with low Th/Sc ratio (0.52) and CIA values (58), moderate Th/U ratio (2.45) and Eu/Eu* negative anomaly (0.76) point to the influence of local sources probably related to tectonic uplift during deposition and scarce weathering. Well-developed calcretes indicate semiarid climatic conditions during burial, and porosity is only preserved after calcite dissolution. A braided fluvial environment was the depositional locus for the Pliocene Salto Formation. The arenites are dominated by rounded quartz, but the original clastic composition was modified due to strong dissolution processes that affected mainly the feldspar population. Low Th/Sc ratio (0.58), low to moderate CIA value (70), very low Th/U ratio (1.45) and moderately negative Eu/Eu* anomaly (0.82) confirm the influence of a mafic source. A wide range of variation of the Ce/Ce* anomaly (0.76–5.86), along with a high concentration of U, Cu, V, As are untypical geochemical characteristics for recycled quartz arenites indicating remobilization during early diagenesis rather than intense reworking. The porosity of the opal-free clastic rocks is extremely high, constituting an important local groundwater reservoir.

Soil contamination in Colombian playgrounds: effects of vehicles, construction, and traffic.

The presence of potentially hazardous elements (PHEs) in playground soils is generally associated with anthropogenic sources such as vehicle traffic, industries, construction sites, and biomass burning. Studies indicate that PHEs are harmful to human health and may even be carcinogenic. Therefore, the aim of this study was to evaluate the physicochemical, morphological, and mineralogical properties of soil samples from three public playgrounds located in the cities of Bogota, Medellin, and Barranquilla. Besides, the possible impacts caused by the aerodynamics of particles in Colombian cities were verified. The morphology, composition, and structure of the nanoparticles (NPs) (< 100nm) present in these soils were evaluated by field emission scanning electron microscopy (FE-SEM) equipped with high-precision field emission (FE) and high-resolution transmission electron microscopy (HR-TEM). Soil samples were predominantly feldspar, quartz, and, to a lesser extent, clay minerals, carbonates, and hematites. The average content of PHEs was anthropogenically enriched in relation to the upper continental crust. As and Sn showed a large spatial variation, indicating the influence of local sources, such as vehicle traffic and industries. There is an inverse relationship between the total concentrations of some elements and their leachable fractions. The accumulation of traffic-derived PHEs has a negative impact on human health and the environment, which is alarming, especially for elements such as Pb, Sb, or As. Therefore, the presence of PHEs should receive greater attention from public health professionals, and limits should be set and exposures controlled. This study includes the construction of a baseline that provides basic information on pollution, its sources, and exposure routes for humans in the vicinity of Colombia's major cities, characterized by their increasing urbanization and industrialization.

PM10 source identification using the trajectory based potential source apportionment (TraPSA) toolkit at Kochi, India

A recently developed open source tool kit named the Trajectory based Potential Source Apportionment (TraPSA) was used to identify the sources of respirable particulates at Kochi, India. Using 24-h average particulate matter data from samples collected at five regulatory monitoring stations over the five-year period from January 2011 to October 2016, local and regional scale analyses were made. Concentration field analysis was performed using back trajectories generated by Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model with inputs from atmospheric reanalysis data. Conditional bivariate probability function analyses were made using local meteorology data to identify the influence of local sources. Most of the stations indicated the contribution from local traffic activities during low wind conditions and from a nearby industrial area especially during high speed winds. Back trajectory analysis identified potential source areas in Kerala as well as in nearby state of Tamil Nadu as contributing to the air quality at Kochi. Arabian sea on the western side was also observed to be a potential source area for Kochi. The study demonstrated the utility of TrapSA as a tool for deriving information about the potential source areas affecting particulate matter mass concentrations.

Sources and diffusive air–water exchange of polycyclic aromatic hydrocarbons in an oligotrophic North–Patagonian lake

Polycyclic aromatic hydrocarbons (PAHs) are semivolatile organic compounds of environmental concern. This study aims to investigate the influence of local sources of anthropogenic PAHs and their air–water exchange fluxes in an oligotrophic North–Patagonian lake in Chile. The monitoring was carried out in Panguipulli Lake during a six-month period during the autumn and winter seasons (March to August 2017) using a high–volume air sampler and a pump system for water samples. We detected and quantified fifteen PAHs in the gas phase (mean ∑15PAHs = 11.6 ng m−3) and dissolved water phase (mean ∑15PAHs = 961.8 pg L−1). Methylphenanthrenes and pyrene dominated the concentrations of PAHs in the studied phases. To determine sources of PAHs we used the PAH ratios of Light Molecular Weight/Heavy Molecular Weight (∑LMW/∑HMW) and Phenanthrene/Anthracene (Phe/Ant). The PAH ratio results revealed a pyrogenic source. We estimated the air–water diffusive exchange fluxes and fugacity ratios for the studied compounds. In general, air–water diffusive exchanges of PAHs showed a net volatilization for the less hydrophobic (log KOW < 4) and lighter PAHs (MW ≤ 170 g mol−1), and a net deposition trend for the more hydrophobic (log KOW 4–7) and higher molecular weight PAHs (MW ≥ 178 g mol−1). We found a significant correlation between log water/air fugacity ratios and log KOW of PAHs. Therefore, it is suggested that this oligotrophic lake acts as a sink by accumulating hydrophobic and mid-high molecular weight PAHs derived mainly from pyrogenic sources. This study is the first attempt to understand the sources and behavior of PAHs in oligotrophic lakes in the Southern Chile where information is scarce regarding the occurrence of PAHs.

Evaluation of urban ozone in the Brahmaputra River Valley

Ozone (O3), carbon monoxide (CO), nitrogen oxides (NOx = NO + NO2), methane (CH4) and non-methane hydrocarbons (NMHCs) were measured in Guwahati in the Brahmaputra River Valley (BRV) of northeastern India from January 1, 2013 to June 30, 2014. The current analysis shows that the annual mean concentrations of O3, CO, CO2, NOx, CH4, and NMHC in Guwahati were 10.5 (±6.30 ppb), 0.5 (±0.2 ppm), 411.7 (±37.5 ppm), 19.6 (±11.6 ppb), 2045(±417 ppb) and 173(±93 ppb), respectively. The pattern of O3concentrations in Guwahati indicated it was strongly influenced by local NOx sources with an adjacent national highway being the likely major source. Thus, the measured O3 values were reduced by local titration. Diel, weekly, and seasonal patterns for each of these gaseous species showed the strong influence of local sources. The mean ventilation coefficient was greater than >6000 m2s during the day in the pre-monsoon season indicating pollutant dispersion. The seasonally average solar radiation (SR) fluxes decreased in the order: pre-monsoon (180 W m−2), monsoon (176 W m−2), post-monsoon (148 W m−2) and winter (110 W m−2).The corresponding mean O3 concentrations were 14.8, 7.5, 6.4, and 10.1 ppb, respectively. In the pre-monsoon season, an impact of SR on the photochemical formation of O3was observed. High O3 winter concentrations were observed likely driven by local biomass burning providing reactive VOCs that contributed to ozone formation.