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This study investigates the contents, distribution patterns, and sources of lanthanoid elements (La to Lu) in aerosols with an aerodynamic diameter ≤10 μm (PM10) in a coastal Caribbean region in order to better constrain the origin of the atmospheric PM contamination. We sampled and analysed PM10 aerosols during 2015 simultaneously at a rural and an urban site in Cienfuegos (Cuba) as well as particles samples from regional contamination sources. Results showed that the sum of the studied lanthanoids concentrations ranged from 0.03 to 13.42 ng m−3 and from 0.51 to 18.75 ng m−3 at the rural and the urban site, respectively. Time variations for the lanthanoid concentrations displayed similar trends and showed that the highest concentrations corresponded to the influence of the African dust for both sites, but presented distinct variability and lower concentrations when dust intrusions were less frequent. The lanthanoid distribution patterns in the rural and urban sites were significantly different, due to the impact of different local combustion sources. Our results were comforted by comparing the degree of fractionation of the lighter and heavier lanthanoids and the δEu and δCe anomalies between our PM10 samples and those of the local sources of contamination. Ultimately, we highlight the added value of lanthanoid elements as reliable indicators for discriminating emission sources and for tracking the origin of atmospheric particulate matter.

Road dust is an indicator widely used when monitoring contamination and evaluating environmental and health risks in urban ecosystems. We conducted an exhaustive characterization of road dust samples coupling their chemical characteristics and stable isotope compositions (C and N) with the aim of evaluating the levels and spatial distribution of local contamination as well as to identify its main source(s) in the coastal city of Cienfuegos (Cuba). Results indicate that the concentrations of several elements (total nitrogen, S, Ca, V, Cu, Zn, Mo, Sn, Hg, and Pb) exceed the background values reported for both Cuban soils and the upper continental crust (UCC) and showed a high variability among the sampling sites. We show that road dust contamination in Cienfuegos induces high associated ecological risks. Among the studied elements, Cd and Hg are the major contributors to the environmental contamination in the city, mainly along busy roads and downtown. δ13C and δ15N, coupled to a multivariate statistical analysis, help associate the studied elements to several local sources of contamination: mineral matter derived from local soils, cement plant and related activities, road pavement alteration, power plant, road traffic, and resuspension of particulate organic matter (POM). Our results suggest that incorporating the chemical and isotope monitoring of road dust may help implement more effective environmental management measures in order to reduce their adverse impact on ecosystems and human health.

Atmospheric deposition is considered to be the major pathway by which substances from the atmosphere enter to the terrestrial and aquatic ecosystems. This study constitutes the first exhaustive report on trace metal deposition in Cuba and is aimed to determine the monthly atmospheric flux of 47 major and trace elements in a Caribbean coastal site and investigate the main sources contributing to deposition. Bulk deposition (average of 46 018 μg m−2 day−1) and fluxes of studied elements showed a high variability and no seasonality with the dry and wet periods, results that we attributed to the fluctuations of the emissions from their main sources rather than to meteorological factors controlling the deposition processes. However, stronger correlations were found between typical crustal elements, which showed a marked seasonality with the presence of African cloud dust in the Caribbean. Lanthanoids element (Eu anomalies and LaN/LuN ratios) helped us to confirm the seasonal influence of African dust in the geochemical composition of bulk deposition in Cienfuegos. Most of the analysed elements were found in the range of variation of those reported in rural environments around the world but, the elements V, Ni, As and Sb reached higher levels, typically found in urban and industrial areas. The elements Sb, Pb, W, Sn, S, Cu, Mo, Nb and P were moderately enriched (10 100), indicating they were mainly derived from anthropogenic sources. The La/V ratios were found to be exclusively lower than 0.06 suggesting a strong influence of anthropogenic V emissions from industries with oil and/or petroleum-coke combustion processes. However, we found that V have a predominantly natural origin in the studied region which appear to be related with deposition processes dominated by large particles. Finally, Principal Component, Multilinear Regression and Cluster analyses led the identification of 5 main sources contributing to the bulk deposition: crustal matter (39.5%), marine aerosol (38.2%), combustions including the wastes incineration, wood and fossil fuel burning (6.7%), industries (8.7%) and road traffic (1.4%).

In Mediterranean areas, dry deposition is a major component of the total atmospheric N input to natural habitats, particularly to forest ecosystems. An innovative approach, combining the empirical inferential method (EIM) for surface deposition of NO 3 − and NH 4 + with stomatal uptake of NH 3 , HNO 3 and NO 2 derived from the DO 3 SE (Deposition of Ozone and Stomatal Exchange) model, was used to estimate total dry deposition of inorganic N air pollutants in four holm oak forests under Mediterranean conditions in Spain. The estimated total deposition varied among the sites and matched the geographical patterns previously found in model estimates: higher deposition was determined at the northern site (28.9 kg N ha −1 year −1 ) and at the northeastern sites (17.8 and 12.5 kg N ha −1 year −1 ) than at the central-Spain site (9.4 kg N ha −1 year −1 ). On average, the estimated dry deposition of atmospheric N represented 77% ± 2% of the total deposition of N, of which surface deposition of gaseous and particulate atmospheric N averaged 10.0 ± 2.9 kg N ha −1 year −1 for the four sites (58% of the total deposition), and stomatal deposition of N gases averaged 3.3 ± 0.8 kg N ha −1 year −1 (19% of the total deposition). Deposition of atmospheric inorganic N was dominated by the surface deposition of oxidized N in all the forests (means of 54% and 42% of the dry and total deposition, respectively). The relative contribution of NO 2 to dry deposition averaged from 19% in the peri-urban forests to 11% in the most natural site. During the monitoring period, the empirical critical loads provisionally proposed for ecosystem protection (10–20 kg N ha −1 year −1 ) was exceeded in three of the four studied forests.

The deterioration of the air quality is a global concern. Daily PM10 samples were simultaneously collected and chemically characterized at an urban and a rural site in Cienfuegos, Cuba between January 2015 and January 2016. A source apportionment study was conducted in order to identify and quantify the main contributions of both local and long-range sources. Concentrations of PM10 varied similarly at the urban and rural site, with annual averages of 35.4 and 24.8 μg m−3, respectively. The highest concentrations were observed between March and August at both sites, when a strong influence of Saharan dust was identified. The PM10 daily limit (50 μg m−3) established in the Cuban legislation for air quality was exceeded by 3 and 8 times in the rural and urban site, respectively. The chemical characterization of PM10 showed important contributions of mineral matter, total carbon and secondary inorganic compounds in the region, with the highest concentrations observed at the urban site. Marine contribution, by contrast, was higher at the rural site. The highest EFs were obtained for the typical road traffic tracers Mo and Cu. Positive matrix factorization (PMF) analysis coupled with conditional bivariate probability function (CBPF) and concentration weighted trajectory (CWT) identified 5 main sources in the studied sites: Saharan intrusions, marine aerosol, combustion sources and secondary aerosols, road traffic and cement plant. The Saharan dust contribution was quantified for the first time in Cuba, proving to be one of the major components of PM10 at both sites. Its daily contribution, indeed, explained more than 60% of the PM10 recorded in 10 of the 11 exceedance events. This study reports the first simultaneous evaluation of PM10 and its chemical composition in urban and rural areas of Cuba, and provides the basis for environmental managers to adopt control strategies to reduce the impact of PM10 pollution in the region.

The constant increase of anthropogenic emissions of aerosols, usually resulting from a complex mixture from various sources, leads to a deterioration of the ambient air quality. The stable isotope compositions (δ13C and δ15N) of total carbon (TC) and nitrogen (TN) in both PM10 and emissions from potential sources were investigated for first time in a rural and an urban Caribbean costal sites in Cuba to better constrain the origin of the contamination. Emissions from road traffic, power plant and shipping emissions were discriminated by coupling their C and N contents and corresponding isotope signatures. Other sources (soil, road dust and cement plant), in contrast, presented large overlapping ranges for both C and N isotope compositions. δ13CPM10 isotope compositions in the rural (average of −25.4 ± 1.2‰) and urban (average of −24.8 ± 1.2‰) sites were interpreted as a mixture of contributions from two main contributors: i) fossil fuel combustion and ii) cement plant and quarries. Results also showed that this last source is impacting more air quality at the urban site. A strong influence from local wood burning was also identified at the rural site. These conclusions were comforted by a statistical analysis using a conditional bivariate probability function. TN and δ15N values from the urban site demonstrated that nitrogen in PM10 was generated by secondary processes through the formation of (NH4)2SO4. The exchange in the (NH4)2SO4 molecule between gaseous NH3 and particle NH4+ under stoichiometric equilibrium may control the observed 15N enrichment. At low nitrogen concentrations in the aerosols, representing PM10 with both the highest primary N and lowest secondary N proportions, comparison with the δ15N of potential sources indicate that emissions from diesel car and power plant emissions may represent the major vectors of primary nitrogen.

There is mounting evidence demonstrating that fluxes and chemical composition of precipitation is substantially changed after passing through tree canopies, particularly in the case of atmospheric nitrogen (N) compounds, with important implications on forest N cycling. However, the processes underpinning those changes – beyond the leaf retention and/or leaching of N compounds - have been less investigated. In a previous study we provided isotopic evidence that biological nitrification in tree canopies was responsible for significant changes in the amount of NO3- from rainfall to throughfall across two UK forests at high nitrogen (N) deposition. This finding strongly suggested that forest canopies are not just passive filters for precipitation water and dissolved nutrients, and that the microbial life hidden within them can be responsible for transforming atmospheric N before it reaches the soil. We extended the isotopic approach at the European scale, and combined it to next-generation sequence analyses with the aim of elucidating canopy nitrification and identify phyllosphere microbes responsible for it. Specifically, in this study we: 1) estimated the relative contribution of NO3- derived from biological canopy nitrification vs. atmospheric deposition by using δ18O and δ17O of NO3- in rainfall and throughfall water; 2) quantified the functional genes related to nitrification, and finally 3) characterized the microbial communities harboured in tree canopies (i.e., phyllosphere) and in the underlying soils for two dominant tree species in Europe (Fagus sylvatica L. and Pinus sylvestris L.) using metabarcoding techniques. We considered twelve sites included in the European ICP Forests monitoring network, chosen along climate and N deposition gradients, spanning from Fennoscandia to the Mediterranean. We will show that presence of nitrifying microbes (as assessed through qPCR) and their activity (as derived from δ18O and δ17O) were detected in the tree canopies across most of the sites, and that canopy nitrification was significantly correlated with atmospheric N deposition. Finally, we will discuss differences in microbial community structure and composition across phyllosphere (and between the two tree species considered), water and soil samples in the investigated forests. Our study demonstrates the potential of integrating stable isotopes with microbial analyses to advance our understanding on canopy-atmosphere interactions and their contribution to N cycling.

Peri-urban vegetation is generally accepted as a significant remover of atmospheric pollutants, but it could also be threatened by these compounds, with origin in both urban and non-urban areas. To characterize the seasonal and geographical variation of pollutant concentrations and to improve the empirical understanding of the influence of Mediterranean broadleaf evergreen forests on air quality, four forests of Quercus ilex (three peri-urban and one remote) were monitored in different areas in Spain. Concentrations of nitrogen dioxide (NO₂), ammonia (NH₃), nitric acid (HNO₃) and ozone (O₃) were measured during 2 years in open areas and inside the forests and aerosols (PM₁₀) were monitored in open areas during 1 year. Ozone was the only air pollutant expected to have direct phytotoxic effects on vegetation according to current thresholds for the protection of vegetation. The concentrations of N compounds were not high enough to directly affect vegetation but could be contributing through atmospheric N deposition to the eutrophization of these ecosystems. Peri-urban forests of Q. ilex showed a significant below-canopy reduction of gaseous concentrations (particularly NH₃, with a mean reduction of 29-38 %), which indicated the feasibility of these forests to provide an ecosystem service of air quality improvement. Well-designed monitoring programs are needed to further investigate air quality improvement by peri-urban ecosystems while assessing the threat that air pollution can pose to vegetation.

This work provides a comprehensive report on the chemical composition of 47 major and trace elements in Tillandsia recurvata (L.) L. and top soil samples from the cities of Cienfuegos and Santa Clara in Cuba. The main aims were to provide new information on the urban pollution degree in Caribbean urban regions where the availability of data of urban health indicators are very limited and to identify the main pollution sources. The abundance of the analyzed elements at both type of samples were different at each urban regions suggesting the influence of various sources. Top soils were slightly contaminated with Zn, V, Ba, Pb, Ni, Cr, Cu, Co and Hg and seriously contaminated with Ni and Cr in Santa Clara. These and other elements such as Se, S, P, Cd, Mo and Ca where highly enriched in T. recurvata indicating a significant impact of anthropogenic sources in the air quality of both urban areas. Cluster analysis helped us associate most of the elements with an anthropogenic origin with three main pollution sources: road traffic, industrial emissions and oil combustion. The spatial variability was particularly useful to identify some of these sources including the emissions from diesel and fuel oil combustion in power stations, biomass burning and metallurgic industries. The results also showed that V and Ni were strongly associated to the oil combustion and that V/Ni ratio indices in both indicators can be used to trace this type of sources. The results presented in this study confirmed the conclusion that both T. recurvata and top soils can be used as feasible indicators of the health of Caribbean urban ecosystems and the distribution of the main pollution sources that are affecting them.

18 pages, 5 figures, supplementary data https://doi.org/10.1016/j.biocon.2021.109175.-- The data supporting the findings of this study are available in the Supplementary Materials (Appendix 3–5, Table A3-A5). Raw datasets (where available) and results summary tables for each analysis of human mobility and empirical datasets are deposited in a github repository: https://github.com/rjcommand/PAN-Environment, The global lockdown to mitigate COVID-19 pandemic health risks has altered human interactions with nature. Here, we report immediate impacts of changes in human activities on wildlife and environmental threats during the early lockdown months of 2020, based on 877 qualitative reports and 332 quantitative assessments from 89 different studies. Hundreds of reports of unusual species observations from around the world suggest that animals quickly responded to the reductions in human presence. However, negative effects of lockdown on conservation also emerged, as confinement resulted in some park officials being unable to perform conservation, restoration and enforcement tasks, resulting in local increases in illegal activities such as hunting. Overall, there is a complex mixture of positive and negative effects of the pandemic lockdown on nature, all of which have the potential to lead to cascading responses which in turn impact wildlife and nature conservation. While the net effect of the lockdown will need to be assessed over years as data becomes available and persistent effects emerge, immediate responses were detected across the world. Thus initial qualitative and quantitative data arising from this serendipitous global quasi-experimental perturbation highlights the dual role that humans play in threatening and protecting species and ecosystems. Pathways to favorably tilt this delicate balance include reducing impacts and increasing conservation effectiveness, The Canada Research Chairs program provided funding for the core writing team. Field research funding was provided by A.G. Leventis Foundation; Agence Nationale de la Recherche, [grant number ANR-18-32–0010CE-01 (JCJC PEPPER)]; Agencia Estatal de Investigaci; Agência Regional para o Desenvolvimento da Investigação Tecnologia e Inovação (ARDITI), [grant number M1420-09-5369-FSE-000002]; Alan Peterson; ArcticNet; Arkadaşlar; Army Corp of Engineers; Artificial Reef Program; Australia's Integrated Marine Observing System (IMOS), National Collaborative; Research Infrastructure Strategy (NCRIS), University of Tasmania; Australian Institute of Marine Science; Australian Research Council, [grant number LP140100222]; Bai Xian Asia Institute; Batubay Özkan; BC Hydro Fish and Wildlife Compensation Program; Ben-Gurion University of the Negev; Bertarelli Foundation; Bertarelli Programme in Marine Science; Bilge Bahar; Bill and Melinda Gates Foundation; Biology Society of South Australia; Boston University; Burak Över; California State Assembly member Patrick O'Donnell; California State University Council on Ocean Affairs, Science & Technology; California State University Long Beach; Canada Foundation for Innovation (Major Science Initiative Fund and funding to Oceans Network Canada), [grant number MSI 30199 for ONC]; Cape Eleuthera Foundation; Centre National d'Etudes Spatiales; Centre National de la Recherche Scientifique; Charles Darwin Foundation, [grant number 2398]; Colombian Institute for the Development of Science and Technology (COLCIENCIAS), [grant number 811–2018]; Colombian Ministry of Environment and Sustainable Development, [grant number 0041–2020]; Columbia Basin Trust; Commission for Environmental Cooperation; Cornell Lab of Ornithology; Cultural practices and environmental certification of beaches, Universidad de la Costa, Colombia, [grant number INV.1106–01–002-15, 2020–21]; Department of Conservation New Zealand; Direction de l'Environnement de Polynésie Française; Disney Conservation Fund; DSI-NRF Centre of; Excellence at the FitzPatrick Institute of African Ornithology; Ecology Project International; Emin Özgür; Environment and Climate Change Canada; European Community: RTD programme - Species Support to Policies; European Community's Seventh Framework Programme; European Union; European Union's Horizon 2020 research and innovation programme, Marie Skłodowska-Curie, [grant number 798091, 794938]; Faruk Eczacıbaşı; Faruk Yalçın Zoo; Field research funding was provided by King Abdullah University of Science and Technology; Fish and Wildlife Compensation Program; Fisheries and Oceans Canada; Florida Fish and Wildlife Conservation Commission, [grant numbers FWC-12164, FWC-14026, FWC-19050]; Fondo Europeo de Desarrollo Regional; Fonds québécois de la recherche nature et technologies; Foundation Segré; Fundação para a Ciência e a Tecnologia (FCT Portugal); Galapagos National Park Directorate research, [grant number PC-41-20]; Gordon and Betty Moore Foundation, [grant number GBMF9881 and GBMF 8072]; Government of Tristan da Cunha; Habitat; Conservation Trust Foundation; Holsworth Wildlife Research Endowment; Institute of Biology of the Southern Seas, Sevastopol, Russia; Instituto de Investigación de Recursos Biológicos Alexander von Humboldt; Instituto Nacional de Pesquisas Espaciais (INPE), Brazil; Israeli Academy of Science's Adams Fellowship; King Family Trust; Labex, CORAIL, France; Liber Ero Fellowship; LIFE (European Union), [grant number LIFE16 NAT/BG/000874]; María de Maeztu Program for Units of Excellence in R&D; Ministry of Science and Innovation, FEDER, SPASIMM,; Spain, [grant number FIS2016–80067-P (AEI/FEDER, UE)]; MOE-Korea, [grant number 2020002990006]; Mohamed bin Zayed Species Conservation Fund; Montreal Space for Life; National Aeronautics and Space Administration (NASA) Earth and Space Science Fellowship Program; National Geographic Society, [grant numbers NGS-82515R-20]; National Natural Science Fund of China; National Oceanic and Atmospheric Administration; National Parks Board, Singapore; National Science and Technology Major Project of China; National Science Foundation, [grant number DEB-1832016]; Natural Environment Research Council of the UK; Natural Sciences and Engineering Research Council of Canada (NSERC), Alliance COVID-19 grant program, [grant numbers ALLRP 550721–20, RGPIN-2014-06229 (year: 2014), RGPIN-2016-05772 (year: 2016)]; Neiser Foundation; Nekton Foundation; Network of Centre of Excellence of Canada: ArcticNet; North Family Foundation; Ocean Tracking Network; Ömer Külahçıoğlu; Oregon State University; Parks Canada Agency (Lake Louise, Yoho, and Kootenay Field Unit); Pew Charitable Trusts; Porsim Kanaf partnership; President's International Fellowship Initiative for postdoctoral researchers Chinese Academy of Sciences, [grant number 2019 PB0143]; Red Sea Research Center; Regional Government of the Azores, [grant number M3.1a/F/025/2015]; Regione Toscana; Rotary Club of Rhinebeck; Save our Seas Foundation; Science & Technology (CSU COAST); Science City Davos, Naturforschende Gesellschaft Davos; Seha İşmen; Sentinelle Nord program from the Canada First Research Excellence Fund; Servizio Foreste e Fauna (Provincia Autonoma di Trento); Sigrid Rausing Trust; Simon Fraser University; Sitka Foundation; Sivil Toplum Geliştirme Merkezi Derneği; South African National Parks (SANParks); South Australian Department for Environment and Water; Southern California Tuna Club (SCTC); Spanish Ministry for the Ecological Transition and the Demographic Challenge; Spanish Ministry of Economy and Competitiveness; Spanish Ministry of Science and Innovation; State of California; Sternlicht Family Foundation; Suna Reyent; Sunshine Coast Regional Council; Tarea Vida, CEMZOC, Universidad de Oriente, Cuba, [grant number 10523, 2020]; Teck Coal; The Hamilton Waterfront Trust; The Ian Potter Foundation, Coastwest, Western Australian State NRM; The Red Sea Development Company; The Wanderlust Fund; The Whitley Fund; Trans-Anatolian Natural Gas Pipeline; Tula Foundation (Hakai Institute); University of Arizona; University of Pisa; US Fish and Wildlife Service; US Geological Survey; Valencian Regional Government; Vermont Center for Ecostudies; Victorian Fisheries Authority; VMRC Fishing License Fund; and Wildlife Warriors Worldwide, With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S

Mercury (Hg) and lead (Pb) isotopic compositions were investigated in mosses and lichens collected in a large mountainous beech forest (Iraty Forest) located on the French-Spanish Pyrenean border. Hg isotopic signature in topsoil samples were also analyzed in selected sampling sites. This is the first work that uses the complementary information of both isotopic systems in two distinct atmospheric bioaccumulators. Mosses and lichens present characteristic accumulation due to their integration times, displaying different information on metal pollution over the area. Hg and Pb concentrations in annual moss shoots represent recent atmospheric accumulation, while whole lichen thalli integrates a process of accumulation over a longer period. Lead isotope ratios in mosses are consistent with reported data corresponding to the actual European atmospheric background (206Pb/207Pb ∼ 1.158), while Hg isotopic composition reflects potential uptake of both dry and wet Hg depositions. For lichens, Pb isotopic composition exhibits the contribution of a longer integration period of both industrial Pb emissions and legacy of leaded gasoline pollution. Hg isotopes in lichens discriminate two main groups: a larger one representing the background atmospheric contribution and a second one corresponding to unexpected higher Hg content. The similarities in odd and even Mass-independent fractionation of Hg isotopes between topsoils and lichens from the larger group, support the idea that foliage uptake is the main input of Hg in soils. The second group of lichens exhibits more negative δ202Hg (down to –4.69‰) suggesting a new source of fractionation in this area, probably related to lichens aging and/or stubble and grass fires due to pastoral activities. This study demonstrates that using both Hg and Pb isotopic signature in lichens and mosses allows to trace atmospheric sources and environmental pathways of these metals in forested ecosystems. This original data set in a remote environment provides also new information on the fate of atmospheric Pb and Hg depositions.

Ammonia (NH3) emissions are linked to eutrophication, plant toxicity and ecosystem shifts from N to P limitation. Bryophytes are key components of terrestrial ecosystems, yet highly sensitive to N deposition. Hence, physiological responses of mosses may be indicative of NH3-related impacts, and thus useful to foresee future ecosystem damages and establish atmospheric Critical Levels (CLEs). In this work, samples of Hypnum cupressiforme Hedw. were seasonally collected along a well-defined NH3 concentration gradient in an oak woodland during a one-year period. We performed a comprehensive evaluation of tissue chemistry, stoichiometry, metabolic enzymes, antioxidant response, membrane damages, photosynthetic pigments, soluble protein content and N and C isotopic fractionation. Our results showed that all the physiological parameters studied (except P, K, Ca and C) responded to the NH3 gradient in predictable ways, although the magnitude and significance of the response were dependent on the sampling season, especially for enzymatic activities and pigments content. Nutritional imbalances, membrane damages and disturbance of cellular C and N metabolism were found as a consequence to NH3 exposure, being more affected the mosses more exposed to the barn atmosphere. These findings suggested significant implications of intensive farming for the correct functioning of oak woodlands and highlighted the importance of seasonal dynamics in the study of key physiological processes related to photosynthesis, mosses nutrition and responses to oxidative stress. Finally, tissue N showed the greatest potential for the identification of NH3-related ecological end points (estimated CLE=3.5μgm-3), whereas highly scattered physiological responses, although highly sensitive, were not suitable to that end.

Bulk/wet and throughfall fluxes of major compounds were measured from June 2011 to June 2013 at four Mediterranean holm-oak (Quercus ilex) forests in the Iberian Peninsula. Regression analysis between net throughfall fluxes and precipitation indicated that the best defined canopy process was leaching for K+ and uptake for NH4+ at all sites. A more variable response between sites was found for Na+, Ca2+, SO42- and Cl−, which suggests that the interplay of dry deposition, leaching and uptake at the canopy was different depending on site climate and air quality characteristics. A canopy budget model (CBM) was used to try to discriminate between the canopy processes and enable to estimate dry deposition and uptake fluxes at three of the sites that complied with the model specifications. To derive N uptake, an efficiency factor of NH4+ vs. NO3− uptake (xNH4) corresponding to moles of NH4+ taken up for each NO3− mol, has to be determined. Up to now, a value of 6 has been proposed for temperate forests, but we lack information for Mediterranean forests. Experimental determination of N absorption on Quercus ilex seedlings in Spain suggests efficiency factors from 1 to 6. Based on these values, a sensitivity analysis for xNH4 was performed and the NH4 N and NO3 N modeled dry deposition was compared with dry deposition estimated with independent methods (inferential modeling and washing of branches). At two sites in NE Spain under a milder Mediterranean climate, the best match was obtained for xNH4 = 6, corroborating results from European temperate forests. Based on this value, total DIN deposition was 12–13 kg N ha−1 y−1 at these sites. However, for a site in central Spain under drier conditions, variation of the NH4+ efficiency factor had little effect on DD estimates (which ranged from 2 to 2.6 kg N ha−1 y−1 with varying xNH4); when added to wet deposition, this produced a total N deposition in the range 2.6–3.4 kg N ha−1 y−1. Dry deposition was the predominant pathway for N, accounting for 60–80% of total deposition, while for base cations wet deposition dominated (55–65%). Nitrogen deposition values at the northwestern sites were close to the empirical critical load proposed for evergreen sclerophyllous Mediterranean forests (15–17 kg N ha−1 y−1). When organic N deposition at these forests is added (3 kg N ha−1 y−1), the total N input to the sites in NE Spain are close to the critical loads for Mediterranean evergreen oak forests.

With the objective of reducing population exposure, vegetation barriers composed by hedges and/or trees are usually located near roads to protect pedestrians from traffic-related pollutants. The main objective of this study is to quantify the effectiveness of this type of barriers. Black Carbon (BC) is used an indicator of the effectiveness of vegetation barrier and its concentration reduction behind the barrier is studied. Computational Fluid Dynamics (CFD) modelling, previously validated against BC experimental data across a vegetation barrier located in an avenue of Pamplona (Spain), is applied to simulate different barrier configurations. Additionally, the contribution of each vegetation effect (aerodynamic and deposition) on this reduction, as well as its sensitivity to different deposition velocities, are investigated. Results show barriers with hedge and trees are effective to locally reduce BC concentrations and suggest that the presence of trees is more crucial in reducing concentration rather than the hedge size or density. At 15 m from road in the presence of a row of trees and a 2 m-height and 2 m-width hedge the average concentration reduction percentage ranges between 45% and 66% (depending on deposition velocity) with respect to the case without vegetation barrier.

In this study, PM10 aerosol samples were collected at 4 urban and 1 rural sites in the region of Cienfuegos (Cuba) and analyzed for their chemical compositions (total carbon (TC), total nitrogen (TN), NH4+, Cl−, NO3− and SO42−) and their stable carbon (δ13C) and nitrogen (δ15N), and radioactive (210Pb, 7Be, 137Cs and 40K) isotope systematics, in order to better constrain both their sources of pollution and their atmospheric dynamics. The average PM10 concentrations varied from 21.67 ± 8.54 μg m−3 at the rural site to 39.01 ± 8.23 μg m−3 at an urban site characterized by high road traffic. Chemical compositions showed low variability and similar abundances of the ionic species, but we observed strong correlations between i) NH4+ and SO42− that indicates the formation of secondary ammonium bisulfate (NH4HSO4), and ii) between PM10 and TC highlighting the significant influence of carbonaceous aerosols. We are reporting here the first 210Pb aerosol concentrations in this region and demonstrate that, coupled with the corresponding 7Be concentrations, they allow characterizing the dynamics of the regional continental air masses. δ13C values in PM10 appear to be controlled by i) emissions from different types of combustion sources, including fossil fuel and biomass burning and ii) carbonate inputs from the industrial activities located around the limestone quarries, east of the city. δ15N values presented large isotope variations that can be explained by kinetic processes and the exchange between gas (NH3) and particle (NH4+) phases during the formation of secondary NH4HSO4, a reaction that was enhanced as Cl− concentrations decreased, revealing the preponderant role of local emissions in the budget of the aerosol nitrogen. This study confirms that isotope analysis is reliable for tracing the origin of aerosols and highlight the importance of a multi-isotope approach.

Atmospheric nitrogen deposition is one of the main threats for biodiversity and ecosystem functioning. Measurement techniques like ion-exchange resin collectors (IECs), which are less expensive and time-consuming than conventional methods, are gaining relevance in the study of atmospheric deposition and are recommended to expand monitoring networks. In the present work, bulk and throughfall deposition of inorganic nitrogen were monitored in three different holm oak forests in Spain during two years. The results obtained with IECs were contrasted with a conventional technique using bottle collectors and with a literature review of similar studies. The performance of IECs in comparison with the conventional method was good for measuring bulk deposition of nitrate and acceptable for ammonium and total dissolved inorganic nitrogen. Mean annual bulk deposition of inorganic nitrogen ranged 3.09-5.43 kg N ha(-1) according to IEC methodology, and 2.42-6.83 kg N ha(-1) y(-1) using the conventional method. Intra-annual variability of the net throughfall deposition of nitrogen measured with the conventional method revealed the existence of input pulses of nitrogen into the forest soil after dry periods, presumably originated from the washing of dry deposition accumulated in the canopy. Important methodological recommendations on the IEC method and discussed, compiled and summarized.

There is a significant lack of data in biomonitoring surveys from southern Europe and other Mediterranean biogeographic areas. This scarcity is mainly due to the impossibility of finding the commonly recommended species in a great portion of these dry environments. The present work was carried out with the aim of assessing the validity of the moss Pleurochaete squarrosa (Brid.) Lindb. (PS) as a feasible alternative in these regions. The study was developed in the Mediterranean area of Navarra, in northern Spain, where the response of PS to multiple atmospheric pollutants (N, Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, Ti and Zn) was compared to that of Hypnum cupressiforme Hedw. (HC), an accepted and widely used species in biomonitoring surveys. Moreover, N isotopic signatures from both species were studied to evaluate their effectiveness when identifying nitrogen emission sources. The enrichment factor (EF) approach was used to evaluate the heavy metal uptake, showing a similar behaviour for both species: low EF for Al, As, Cr and Fe; intermediate for Mn, Ni, Pb and Sb; and high for Cd, Cr, Hg and Zn. Equally, both species depicted the same N deposition patterns across the study area. However, regarding δ 15 N, PS gave a more congruent picture with the location of the main sources of N emissions in the area. These data suggest that PS may be a suitable biomonitor to fill the aforementioned gaps in Mediterranean biogeographic areas.

The present work was carried out to assess the effect of atmospheric ammonia (NH3) on soil physicochemical properties, soil enzymatic activities (β-glucosidase -β-GLU-, nitrate reductase –NR-, urease –UR-, protease –PRO-, acid phosphatase –PHO-, dehydrogenase –DHA-), soil microbial biomass and soil respiration. The study was conducted along a NH3 gradient in a Q. pubescens Milld. forest in the vicinity of two livestock farms. Because of NHy (NHy: NH3 and NH4+) deposition, N saturation was detected up to 330 m from the farms. This excess of N led to a decrease in soil C:N and an increase in soil nitrification processes, which resulted in an accumulation of the heavy N isotope (15N) in the soil. N saturation was also reflected in the activity of NR enzyme, which was inhibited. On the other hand, while UR enzyme was inhibited close to the farms possibly due to the high amount of N-NH4+ resulting from the hydrolysis of NH3, PRO activity was stimulated by the presence of organic nitrogen compounds and the need of soil organisms to meet the C demand. In addition, the activity of PHO and β-GLU enzymes was regulated by the relative amount of C and P that organisms need. Regarding biological variables, enhanced NH3 reduced soil microbial biomass and biomass respiratory efficiency. Finally, soil enzyme activities and soil microbial biomass have proved to be good biological indicators of soil quality.

Ajuts: This manuscript resulted from the 1st "Committee on Air Pollution Effects Research on Mediterranean Ecosystems" (CAPERmed) Conference celebrated in Lisbon, 2014 (http://capermed.weebly.com/). All attendants to this conference are, therefore, greatly acknowledged. Fundação para a Ciência e Tecnologia (FCT) is acknowledged through the Post Doc grant SFRH/BPD/85419/2012 to Teresa Dias and the Investigador grant to Silvana Munzi. ADM, EP and PS thank the LIFE10 ENV/FR/208 project MOTTLES. EP thanks also the Fondazione Cassa di Risparmio di Firenze (2013/7956). ROH is supported by a Juan de la Cierva Fellowship (IJCI-2014-21252) of the Spanish Ministry of Economy and Competitiveness. The authors declare no conflicts of interest. Mediterranean Basin ecosystems, their unique biodiversity, and the key services they provide are currently at risk due to air pollution and climate change, yet only a limited number of isolated and geographically-restricted studies have addressed this topic, often with contrasting results. Particularities of air pollution in this region include high O3 levels due to high air temperatures and solar radiation, the stability of air masses, and dominance of dry over wet nitrogen deposition. Moreover, the unique abiotic and biotic factors (e.g., climate, vegetation type, relevance of Saharan dust inputs) modulating the response of Mediterranean ecosystems at various spatiotemporal scales make it difficult to understand, and thus predict, the consequences of human activities that cause air pollution in the Mediterranean Basin. Therefore, there is an urgent need to implement coordinated research and experimental platforms along with wider environmental monitoring networks in the region. In particular, a robust deposition monitoring network in conjunction with modelling estimates is crucial, possibly including a set of common biomonitors (ideally cryptogams, an important component of the Mediterranean vegetation), to help refine pollutant deposition maps. Additionally, increased attention must be paid to functional diversity measures in future air pollution and climate change studies to establish the necessary link between biodiversity and the provision of ecosystem services in Mediterranean ecosystems. Through a coordinated effort, the Mediterranean scientific community can fill the above-mentioned gaps and reach a greater understanding of the mechanisms underlying the combined effects of air pollution and climate change in the Mediterranean Basin.

To assess the impact of vehicular emissions on a mixed conifer forest, we measured the contents of the trace elements, N, C, and their respective natural isotopes (δ(15)N and δ(13)C), in the epiphytic lichen, L. vulpina. The samples were collected along transects perpendicular to Interstate 80 (I-80) and along a more remote, secondary forest road (R07). Distance to the road verge, trunk cover, and stand basal area were also recorded. Percent N ranged from 1.10% to 2.00% near I-80 and from 0.78% to 1.13% along R07. Concentrations of N, (15)N, Na, As, Pb, and Zn were enhanced in lichen samples near I-80 and were negatively correlated with distance from the road. Trunk cover values differed between roads (p

Altres ajuts: This research was also funded by the project from Autonomous Government of Madrid AGRISOST-CM (P2013/ABI-2717). CIEMAT work in this study was partially supported by an agreement between the Spanish Ministry of Agriculture, Food and Environment and CIEMAT on Critical loads and levels. The utilization of Tres Cantos monitoring site was possible thanks to an agreement between CIEMAT and Ayuntamiento de Madrid. To assess the impact of nitrogen (N) pollutants on forest ecosystems, the role of the interactions in the canopy needs to be understood. A great number of studies have addressed this issue in heavily N-polluted regions in north and central Europe. Much less information is available for the Iberian Peninsula, and yet this region is home to mountain forests and alpine grasslands that may be at risk due to excessive N deposition. To establish the basis for ecology-based policies, there is a need to better understand the forest response to this atmospheric impact. To fill this gap, in this study, we measured N deposition (as bulk, wet, and throughfall fluxes of dissolved inorganic nitrogen) and air N gas concentrations from 2011 to 2013 at four Spanish holm oak (Quercus ilex) forests located in different pollution environments. One site was in an area of intensive agriculture, two sites were influenced by big cities (Madrid and Barcelona, respectively), and one site was in a rural mountain environment 40 km north of Barcelona. Wet deposition ranged between 0.54 and 3.8 kg N ha⁻¹ year⁻¹ for ammonium (NH₄⁺)-N and between 0.65 and 2.1 kg N h⁻¹ year⁻¹ for nitrate (NO₃⁻)-N, with the lowest deposition at the Madrid site for both components. Dry deposition was evaluated with three different approaches: (1) a canopy budget model based in throughfall measurements, (2) a branch washing method, and (3) inferential calculations. Taking the average dry deposition from these methods, dry deposition represented 51-67% (reduced N) and 72-75% (oxidized N) of total N deposition. Canopies retained both NH₄⁺-N and NO₃⁻N, with a higher retention at the agricultural and rural sites (50-60%) than at sites located close to big cities (20-35%, though more uncertainty was found for the site near Madrid), thereby highlighting the role of the forest canopy in processing N pollutant emissions.

The signal crayfish Pacifastacus leniusculus Dana, 1852 is a successful invasive species in the Iberian Peninsula. This is of particular conservation concern, as fish fauna is highly endemic and also threatened within this ecoregion. The aim of this study was to analyze behavioral interactions and trophic overlap between signal crayfish and native fishes in Iberian rivers (northern Spain). Video cameras were used to record fish &ldquo, dominance/evasion&rdquo, after spatial encounters with crayfish. Diet composition and isotopic signatures (&delta, 13C and &delta, 15N) were compared to evaluate the niche overlap. Fish were dominant in 25% of the encounters with juvenile crayfish, whereas this percentage was only 4% with adult crayfish. Observations showed a high fish &ldquo, evasion&rdquo, response for Pyrenean stone loach Barbatula quignardi (Bǎcescu-Meşter, 1967) (&gt, 30%). Dietary results showed a high trophic overlap between signal crayfish with the pelagic Pyrenean minnow Phoxinus bigerri Kottelat, 2007 and the benthic loach. However, the isotopic niche overlap was low, with brown trout Salmo trutta L., 1758 showing the highest area (only 0.1 &permil, 2). Overall, our findings suggest that interferences may occur with native species for food (i.e., benthic invertebrates). Consequently, measures should be applied to control invasive crayfish in Iberian rivers.

Wet N deposition comprises oxidised (nitrate) and reduced (ammonium) N forms in proportions that vary spatially with source and topography. Field evidence of long-term N form effects on semi-natural ecosystems and how these are modified by phosphorus and potassium availability are lacking. This study describes cover changes for some key peatland species and litter chemistry from Sphagnum capillifolium, Calluna and Eriophorum vaginatum, and peat in response to 9 years of N treatment. Ammonium and nitrate as NH4Cl or NaNO3 were provided to replicate plots in rainwater spray at +8 (low) or +56 (high) kg N ha−1 year, with and without PK via an automated system coupled to site meteorological conditions. Reduced N caused greater N accumulation in all key species than oxidised N, especially at higher doses, but cover declined more, though not significantly so, with oxidised than reduced N at the high N dose. Overall the detrimental effects of high N on Sphagnum and Calluna cover were significant but small. By comparison PK inclusion with 56 kg N ha−1 year as oxidised N, not reduced N, had devastating effects on cover, causing both S. capillifolium and Calluna to decrease 3–5-fold, facilitating invasion and expansion of nitrophiles, non-characteristic bog plants e.g. Epilobium angustifolium, Epilobium palustre, Juncus effusus, Digitalis purpurea and Dryopteris dilatata. N form appears to be significant for peatlands because of its effects on pH. The significance of changes in plant cover for peat chemistry and decomposition for biogeochemistry is discussed.

A microwave digestion method in a closed vessel was developed for the simultaneous determination of trace and major elements, with the highest possible recoveries, in atmospheric aerosols using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). This method was developed to quantify the concentration of Na, Mg, Al, P, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Cd, Sb, Cs, Ba, La, Ce and Pb present in quartz filters containing particulate matter (PM10). The performance of the procedure was evaluated by analysis of the standard reference material NIST 1633b and CTA-FFA-1. Different combinations of nitric acid (HNO3), hydrogen peroxide (H2O2), hydrofluoric acid (HF) and hydrochloric acid (HCl) were tested to improve the recovery factors for the studied elements. The addition of a large amount (3 mL) of HF was required to fully dissolve the quartz filters. This fact made difficult the obtention of high recoveries for alkali (Rb, Cs), alkaline earth (Mg, Ca, Ba), and rare earth (La, Ce) elements, which showed the lowest recoveries. In this study three different digestion methods were assessed using a closed evaporation system, the addition of boric acid and a mixture of both procedures to minimize the effects of residual fluoride.

The objective of the present work was to verify and compare the performance of different geochemical indices employed to identify the anthropogenic origin of selected heavy metals and other trace elements in soils. To that end, two background values, the upper continental crust and the metal content in the bed rock, were used and obtained from a forested basin of the western Pyrenees. The enrichment factor (EF), geo-accumulation index (Igeo), and contamination factor (Cif) were finally evaluated for their ability to determine anthropogenic contamination: Results indicate that an in-depth knowledge of the bed rock geochemistry and the geological background content is essential to distinguish between the natural variability of soils and any anthropogenic contribution of heavy metals. Although both EF and Cif show a similar ability to detect soil contamination, the latter is proposed as a more appropriate and sensitive marker given its ability for finding episodically elevated contamination levels.

PM10 and PM2.5 levels, concentrations of major components, trace elements, pH, conductivity and source apportionment were evaluated from samples collected during 2009 at three different locations (rural, urban and urban-traffic) in Navarra (North of Spain). Mean particulate matter concentrations were below the annual limit value for PM10 and annual target value for PM2.5 established by the European Directive 2008/50/EC and similar to those recorded at other locations in the North of Spain. The major components of PM10 in the three sampling stations were, by order of importance, OC + EC, NO3- and non-marine sulphate (nmSO42-), whereas the major components of PM2.5 were OC + EC, nmSO42- and NO3-. ΔpH values indicated that PM2.5 samples were more acidic than PM10 ones. The 90–96% of total trace elements contribution in PM2.5 and PM10 were described by P, Ti, Cr, Mn, Ni, Cu, Zn, Sr, Sn, Ba and Pb. Concentrations of those elements were lower than values obtained in Pamplona in 2002–2004 and similar to those found in other sub-urban and urban Spanish cities. PMF model identified 5 principle sources for PM10 and PM2.5 in Iturrama and Plaza de la Cruz (crustal, secondary sulphate, secondary nitrate, traffic and sea-salt aerosols) and 4 sources for PM10 in Bertiz (crustal, secondary sulphate, secondary nitrate and sea-salt).

This study was carried out in order to assess both the deposition of heavy metal and nitrogen in a mountain ecosystem with low levels of metal deposition and its possible interactions with factors such as lithology and topography. For this purpose, samples of Hypnum cupressiforme Hedw. and topsoils were collected in a forest catchment within Bertiz Natural Park, an International Cooperative Programme on Integrated Monitoring site. Trace metals levels in mosses can be considered low compared with values reported elsewhere in Europe, and the dust soil mineral particles seemed to be the main source of these values. Only Cd and Hg presented external inputs, probably with an anthropic origin, for mosses according to the enrichment factor values, whereas historical pollution-related deposition in soils was determined for Pb, Cu, and Ni, attending to their total/extractable ratio.

Ground-level dynamics of O3, NO x and benzene, toluene, ethylbenzene and xylenes were characterised at rural sites in the medium Ebro River Basin (Northern Spain) from April to September (2003–2007) and by means of automated and passive monitoring. The study registered high O3 levels within the area, which were influenced by traffic emissions, and a monthly evolution of these levels consistent with the occurrence of a broad summer maximum, typical of polluted areas. The mean ozone concentration registered in the studied area by means of passive sampling was 87 ± 12 μg m−3. The 2008/50/EC objective value for the protection of vegetation was widely exceeded during this study (AOT40 = 57,147 ± 14,114 μg m−3 h), suggesting that current ambient levels may pose a risk for crops and vegetation in this important agroindustrial region.

A biomonitoring survey using the moss species Hypnum cupressiforme Hedw. was performed in the North of Navarra (Spain) in 2006. The levels of V, Cr, Mn, Ni, Cu, Zn, As, Zr, Cd, Hg and Pb, and the total nitrogen content were determined in the samples by means of ICP-MS, CV-AA, and the Kjeldahl method. PCA analysis showed a differentiation between lithogenic (V, Cr, Mn, Ni, As and Zr) and anthropogenic elements (Mn, Cu, Zn, Cd, Hg and Pb). Spatial distribution maps were drawn using the kriging method, in order to identify the most affected areas and the main pollution sources. A similar spatial distribution was observed for the elements belonging to each group separated by the PCA, showing an important contribution from metal industries located in the Basque Country, as well as influence of long-range transboundary pollution processes. Background levels were also determined for the study area, along with the contamination factor for the different elements analysed. Mosses seemed to be good biomonitors of N deposition in areas of accumulation.

Indoor and outdoor concentrations of volatile organic compounds (VOCs) were measured in 30 pubs and cafes (13 smoking, 13 non-smoking and 4 mixed atmospheres) in Pamplona city, Spain. The samples were obtained using a sampling pocket pump connected to stainless steel tubes filled with Tenax TA, and subsequently analysed by means of GC–MS coupled to a thermal desorption unit. The levels registered were found to be generally higher indoors. Smoking, cleaning products and the entrance of outdoor pollutants were identified as the main sources of these compounds, the later being especially relevant in non-smoking areas. BTEX concentrations were higher during the winter months and higher in smoking areas also.

Fagus sylvatica L. is the most representative tree species in forests of Navarre (Northern Spain), in the boundary between the Euro-Siberian and Mediterranean regions. In this paper we assess the nutritional status of 30 beech forest stands selected in this area which belong to three vegetation series: Saxifrago hirsutae – Fageto sylvaticae S., Scillo lilio-hyacinthi – Fageto sylvaticae S. and Carici sylvaticae – Fageto sylvaticae S. We also determine the foliar content of sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), nitrogen (N) phosphorus (P) and sulphur (S) for these stands. Additionally, the crown condition was also assessed. Average stand values for Ca, Na, Mg and K foliar content were found to be above the reference values in many of the stands. Consequently, macronutrient ratios for these elements (N/Ca, K/Ca, Ca/Mg and K/Mg) were either above or below the range considered to be suitable for the harmonious growth of beech trees, but no evidence was found that this had a deleterious effect on the health status of the beech trees. Results showed that crown condition in these stands was good, with an average 12.2% of trees considered as damaged compared to an EU 22.8% for the same period. No symptoms of N-saturation were found; on the contrary, N is believed to still be a limiting factor for tree growth in the area.

Document Type : Proceedings Paper Conference Date : OCT 19-21, 2012 Conference Location : Pamplona, SPAIN Conference Host : Univ Navarre; International audience; The concentrations of 15 selected polycyclic aromatic hydrocarbons (PAHs) were determined in daily PM10 samples collected at a rural site, an urban site and a traffic site in Navarra during 2009. PAHs were extracted by microwave-assisted extraction (MAE) from the corresponding quartz filters and later analyzed by gas chromatography/mass spectrometry (GC/MS). An intensive annual study was enabled with this analytical procedure as turnover is multiplied by 50 with MAE in comparison with the classical extraction technique (Soxhlet). The annual average total concentrations of the 15 target compounds ranged from 0.6 ng m(-3) to 1.2 ng m(-3) at the rural and traffic sampling stations respectively, showing up to four times higher PAHs concentrations in winter than in summer. When compared to other European cities, Pamplona registered significantly lower PAHs values. Other pollutants like NOx, CO and PM10 were found to be well correlated with PAHs, and O-3 presented a negative correlation. The results of diagnostic ratios and principal component analysis (PCA) revealed the high influence of diesel and gasoline emissions in the three studied areas, although, other main sources were also found.

A biomonitoring survey using the moss species Hypnum cupressiforme Hedw. was conducted in the surroundings of two steel plants located in the North of Spain. Levels of V, Cr, Ni, Cu, Zn, As, Cd, Hg, Pb and N were determined. Very high concentrations in the areas of study were detected when compared to nearby unaffected regions. Similar trends were observed for all the elements in the differently orientated transects, showing an appreciable influence of the NW prevailing winds of the region in the dispersion of pollutants, as well as a clear decreasing gradient in the concentrations of metals in mosses within a distance of 1500 meters from the facilities. A differentiation between the elements emitted by the chimney as result of the industrial activity (V, Cr, Ni, Cu and As) and those with a high presence in steel slag deposits (Zn, Cd, Hg and Pb) was observed. The range of contamination was also established by means of the Contamination Factor, indicating a category 4 out of 6 categories, which shows the high levels reported in the areas of study. A different dynamic was registered for nitrogen regarding the rest of the heavy metals analysed except for Hg, probably due to the elevated volatility and mobility of both elements, as well as their high persistence in the atmosphere.

Ambient concentrations of volatile organic compounds (VOC) and nitrogen dioxide (NO2) were measured by means of passive sampling at 40 sampling points in a medium-size city in Northern Spain, from June 2006 to June 2007. VOC and NO2 samplers were analysed by thermal desorption followed by gas chromatography/mass-selective detector and by visible spectrophotometry, respectively. Mean concentrations of benzene, toluene, ethylbenzene, xylenes, propylbenzene, trimethylbenzenes, and NO(2) were 2.84, 13.26, 2.15, 6.01, 0.59, 1.32 and 23.17 microg m(-3) respectively, and found to be highly correlated. Their spatial distribution showed high differences in small distances and pointed to traffic as the main emission source of these compounds. The lowest levels of VOC and NO2 occurred during summer, owing to the increase in solar radiation and to lower traffic densities. Mean concentrations of benzene and NO2 exceeded the European limits at some of the monitored points.

This study examines the exposure level of passengers and drivers to VOC in public buses in a medium-size metropolitan area (Northern Spain). In-vehicle monitoring was performed on different routes, on peak and non-peak hours, during January and February 2007. A total of 112 air samples were collected onto adsorbent tubes and analysed by thermal desorption (TD) and gas chromatography/mass selective detector (GC/MSD) technique. Statistical differences were found among route to route concentrations, with those routes with major prevalence in the commercial area of the city displaying higher values; differences between peak and non-peak hours were also observed. A decrease in VOC concentrations was also registered during the weekend. BTEX ratios were estimated and found to be related to traffic emissions and similar for all the surveyed routes. Correlations confirmed traffic as the main emission source for BTEX and trimethylbenzene, their concentrations being highly associated to changes in meteorological conditions.

An ambient air quality study was undertaken in two cities (Pamplona and Alsasua) of the Province of Navarre in northern Spain from July 2001 to June 2004. The data were obtained from two urban monitoring sites. At both monitoring sites, ambient levels of ozone, NOx, and SO2 were measured. Simultaneously with levels of PM(10) measured at Alsasua (using a laser particle counter), PM(10) levels were also determined at Pamplona (using a beta attenuation monitor). Mean annual PM(10) concentrations in Pamplona and Alsasua reached 30 and 28 microg m(-3), respectively. These concentrations are typical for urban background sites in Northern Spain. By using meteorological information and back trajectories, it was found that the number of exceedances of the daily PM(10) limit as well as the PM(10) temporal variation was highly influenced by air masses from North Africa. Although North African transport was observed on only 9% of the days, it contributed the highest observed PM(10) levels. Transport from the Atlantic Ocean was observed on 68% of the days; transport from Europe on 13%; low transport and local influences on 7%; and transport from the Mediterranean region on 3% of the days. The mean O3 concentrations were 45 and 55 microg m(-3) in Pamplona and Alsasua, respectively, which were above the values reported for the main Spanish cities. The mean NO and NO2 levels were very similar in both sites (12 and 26 microg m(-3), respectively). Mean SO2 levels were 8 microg m(-3) in Pamplona and 5 microg m(-3) in Alsasua. Hourly levels of PM(10), NO and NO2 showed similar variations with the typically two coincident maximums during traffic rush hours demonstrating a major anthropogenic origin of PM(10), in spite of the sporadic dust outbreaks.

Ambient concentrations of volatile organic compounds (VOCs) were measured at 40 rural sampling points in Navarre (northern Spain). Air samples were collected by means of sorbent passive sampling and analyzed by thermal desorption (TD) and gas chromatography/mass-selective detector (GC/MSD). A total of 140 VOCs were identified during the study, which was carried out between May to October 2004 for a total of a 10 biweekly sampling campaigns. Concentrations of benzene, toluene, ethylbenzene, m / p -xylenes, o -xylene (BTEX) and 1,3,5-trimethylbenzene were determined in order to investigate their temporal and spatial distributions. Geostatistical analysis pointed to traffic as the main emission source of these compounds. Supporting this idea, BTEX and nitrogen oxides concentrations were found to be highly significantly correlated ( r = 0.495, P = 0.001), whereas a strong negative correlation between BTEX and ozone was also observed ( r = − 0.355, P = 0.025). The concentrations for the BTEX group were similar to the values that have been previously reported for other rural areas.

In grassland systems, cattle and sheep urine patches are recognized as nitrous oxide (N2O) emission hot spots due to the high urinary nitrogen (N) concentrations. Hippuric acid (HA) is one of the constituents of ruminant urine that has been reported as a natural inhibitor of soil N2O emissions. The aim of this study was to examine the potential for elevated ruminant urine HA concentrations to reduce N2O emissions, in situ, on an acidic heavy clay soil under poorly drained conditions (WFPS > 85%). A randomized complete block design experiment with three replications and four treatments was conducted using the closed-static-flux chamber methodology. The four treatments were applied inside the chambers: control with no artificial urine application (C), control artificial urine (U), and enriched artificial urine containing two rates of HA (55.8 and 90 mM, U+HA1, U+HA2). Soil inorganic-N, soil dissolved organic carbon (DOC), soil pH as well as N2O and methane (CH4) fluxes were monitored over a 79-day period. Although N2O emissions were not affected by the HA enriched urine treatments, U+HA2 positively affected the retention of N as NH4+ until day 3, when the soil pH dropped to values

Mites and springtails are important members of soil mesofauna and have been proven to be good bioindicators of airborne pollutants. We studied the surrounding area of a steel mill located in a mountain valley of North Spain. Previous studies had documented the existence of a pollution gradient in this area due to the emissions of the factory, thus providing an interesting site to investigate the potential effects of pollutants (heavy metals and nitrogen) on soil biodiversity. The density of Acari and Collembola significantly decreased with the increase in concentration of Cr, Mn, Zn, Cd and Pb. Mites appeared to be more sensitive to heavy metal pollution than springtails. Likewise, the density of these microarthropoda was lower in those soils exhibiting higher nitrogen content. The species composition of the community of Acari and Collembola changed according to heavy metal pollution. Significant differences in abundance, species richness and diversity were observed between the communities of the sampling sites. Some species were exclusive of the less polluted sites, while other appeared in the most contaminated ones. This different response of soil mesofauna to pollutants suggests that some mite or springtail species could be used as bioindicators of heavy metal pollution.