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PM10 aerosol was sampled in Santiago, the largest island of Cabo Verde, for 1 year, and analysed for elements, ions and carbonaceous material. Very high levels of dust were measured during the winter months, as a result of the direct transport of dust plumes from the African continent. Ionic and mass balances (IMBs) were applied to the analysed compounds, permitting the determination of six to seven different processes and source contributions to the aerosol loading: insoluble and soluble dust, sea salt, carbonaceous material and secondary inorganic compounds resulting from the reaction of acidic precursors with ammonia, sea salt and dust. The mass balance could be closed by the consideration and estimation of sorbed water that constituted 20 %-30% of the aerosol mass. The balance methodology was compared with positive matrix factorisation (PMF), showing similar qualitative source composition. In quantitative terms, while for soil dust and secondary inorganic compound source classes, the results are similar, for other sources such as sea-salt spray there are significant differences in periods of dust episodes. The discrepancies between both approaches are interpreted based on calculated source profiles. The joint utilisation of the two methodologies, which are complementary, gives con- fidence in our capability for the correct source apportionment of aerosol particles. [ABSTRACT FROM AUTHOR]

This paper presents the light-scattering properties of atmospheric aerosol particles measured over the past decade at 28 ACTRIS observatories, which are located mainly in Europe. The data include particle light scattering (σsp) and hemispheric backscattering (σbsp) coefficients, scattering Ångström exponent (SAE), backscatter fraction (BF) and asymmetry parameter (g). An increasing gradient of σsp is observed when moving from remote environments (arctic/mountain) to regional and to urban environments. At a regional level in Europe, σsp also increases when moving from Nordic and Baltic countries and from western Europe to central/eastern Europe, whereas no clear spatial gradient is observed for other station environments. The SAE does not show a clear gradient as a function of the placement of the station. However, a west-to-east-increasing gradient is observed for both regional and mountain placements, suggesting a lower fraction of fine-mode particle in western/south-western Europe compared to central and eastern Europe, where the fine-mode particles dominate the scattering. The g does not show any clear gradient by station placement or geographical location reflecting the complex relationship of this parameter with the physical properties of the aerosol particles. Both the station placement and the geographical location are important factors affecting the intraannual variability. At mountain sites, higher σsp and SAE values are measured in the summer due to the enhanced boundary layer influence and/or new particle-formation episodes. Conversely, the lower horizontal and vertical dispersion during winter leads to higher σsp values at all low-altitude sites in central and eastern Europe compared to summer. These sites also show SAE maxima in the summer (with corresponding g minima). At all sites, both SAE and g show a strong variation with aerosol particle loading. The lowest values of g are always observed together with low σsp values, indicating a larger contribution from particles in the smaller accumulation mode. During periods of high σsp values, the variation of g is less pronounced, whereas the SAE increases or decreases, suggesting changes mostly in the coarse aerosol particle mode rather than in the fine mode. Statistically significant decreasing trends of σsp are observed at 5 out of the 13 stations included in the trend analyses. The total reductions of σsp are consistent with those reported for PM2.5 and PM10 mass concentrations over similar periods across Europe. [ABSTRACT FROM AUTHOR]

This study focuses on the analysis of aerosol hygroscopic growth during the Sierra Nevada Lidar AerOsol Profiling Experiment (SLOPE I) campaign by using the synergy of active and passive remote sensors at the ACTRIS Granada station and in situ instrumentation at a mountain station (Sierra Nevada, SNS). To this end, a methodology based on simultaneous measurements of aerosol profiles from an EARLINET multi-wavelength Raman lidar (RL) and relative humidity (RH) profiles obtained from a multi-instrumental approach is used. This approach is based on the combination of calibrated water vapor mixing ratio (r) profiles from RL and continuous temperature profiles from a microwave radiometer (MWR) for obtaining RH profiles with a reasonable vertical and temporal resolution. This methodology is validated against the traditional one that uses RH from colocated radiosounding (RS) measurements, obtaining differences in the hygroscopic growth parameter (y) lower than5% between the methodology based on RS and the one presented here. Additionally, during the SLOPE I campaign the remote sensing methodology used for aerosol hygroscopic growth studies has been checked against Mie calculations of aerosol hygroscopic growth using in situ measurements of particle number size distribution and submicron chemical composition measured at SNS. The hygroscopic case observed during SLOPE I showed an increase in the particle backscatter coefficient at 355 and 532 nm with relative humidity (RH ranged between 78 and 98 %), but also a decrease in the backscatter-related Ångström exponent (AE) and particle linear depolarization ratio (PLDR), indicating that the particles became larger and more spherical due to hygroscopic processes. Vertical and horizontal wind analysis is performed by means of a co-located Doppler lidar system, in order to evaluate the horizontal and vertical dynamics of the air masses. Finally, the Hänel parameterization is applied to experimental data for both stations, and we found good agreement on measured with remote sensing (y532 = 0:48 ± 0:01 and y355 = 0:40±0:01) with respect to the values calculated using Mie theory (y532 = 0:53 ± 0:02 and y355 = 0:45 ± 0:02), with relative differences between measurements and simulations lower than 9% at 532 nm and 11% at 355 nm. [ABSTRACT FROM AUTHOR]

This paper presents the light scattering properties of atmospheric aerosol particles measured over the past decade at 28 ACTRIS observatories, located mainly in Europe. The data include particle light scattering (σ sp) and hemispheric backscattering (σbsp) coefficients, scattering Ångström exponent (SAE), backscatter fraction (BF) and asymmetry parameter (g). A large range of ssp was observed across the network. Low ssp values were on average measured in Nordic and Baltic countries and in Western Europe whereas the highest σsp were measured at regional sites in eastern and central Europe. In these regional areas the SAE was also high indicating the predominance of fine-mode particles. On average, the SAE was lower in the Nordic and Baltic, western and southern countries suggesting a lower fraction of fine-mode particle compared to central and eastern Europe. An increasing gradient of ssp was observed when moving from mountain to regional and to urban sites. Conversely, the mass-independent SAE and g parameters did not show the same gradient. At all sites, both SAE and g varied greatly with aerosol particle loading. The lowest values of g were always observed under low ssp indicating a larger contribution from particles in the smaller accumulation mode. Then, g steeply increased with increasing ssp indicating a progressive shift of the particle size distribution toward the larger end of the accumulation mode. Under periods of high particle mass concentrations, the variation of g was less pronounced whereas the SAE increased or decreased suggesting changes mostly in the coarse aerosol particles mode rather than in the fine mode. The station placement seemed to be the main parameter affecting the intra-annual variability. At mountain sites, higher σsp was measured in summer mainly because of the enhanced boundary layer influence. Conversely, less horizontal and vertical dispersion in winter led to higher σsp at all low altitude sites in central and eastern Europe compared to summer. On average, these sites also showed SAE maxima in summer (and correspondingly g minima). Large intra-annual variability of SAE and g was observed also at Nordic and Baltic countries due to seasonal-dependent transport of different air masses to these remote sites. Statistically significant decreasing trends of σsp were observed at 5 out of 13 stations included in trend analyses. The total reductions of ssp were consistent with those reported for PM2.5 and PM10 mass concentrations over similar periods across Europe. [ABSTRACT FROM AUTHOR]

The inorganic and organic geochemistry of aerosol particulate matter (APM) was studied in a major olive grove area from Southwest Europe (Baena, Spain). The biomass consists of olive tree branches and the solid waste resulting of the olive oil production. Moreover, high PM 10 levels were obtained (31.5 μg m − 3 ), with two days of exceedance of the daily limit of 50 μg m − 3 (2008/50/CE; EU, 2008) during the experimental period. A high mean levoglucosan concentration was obtained representing up 95% of the total mass of the isomers analysed (280 ng m − 3 ), while galactosan and mannosan mean concentrations were lower (8.64 ng m − 3 and 7.86 ng m − 3 , respectively). The contribution of wood smoke in Baena was estimated, representing 19% of OC and 17% of OM total mass. Positive matrix factor (PMF) was applied to the organic and inorganic aerosols data, which has permitted the identification of five source categories: biomass burning, traffic, mineral dust, marine aerosol and SIC (secondary inorganic compounds). The biomass burning category reached the highest mean contribution to the PM 10 mass (41%, 17.6 μg m − 3 ). In light of these results, the use of biomass resulting from the olive oil production for residential heating and industry must be considered the most important aerosol source during the winter months. The results of this paper can be extrapolated to other olive oil producing areas in the Mediterranean basin. Therefore, a fuller understanding of this type of biomass combustion is required in order to be able to establish appropriate polices and reduce the environmental impact on the population. [ABSTRACT FROM AUTHOR]

A detailed spatial and temporal assessment of urban NH 3 levels and potential emission sources was made with passive samplers in six major Spanish cities (Barcelona, Madrid, A Coruña, Huelva, Santa Cruz de Tenerife and Valencia). Measurements were conducted during two different periods (winter–autumn and spring–summer) in each city. Barcelona showed the clearest spatial pattern, with the highest concentrations in the old city centre, an area characterised by a high population density and a dense urban architecture. The variability in NH 3 concentrations did not follow a common seasonal pattern across the different cities. The relationship of urban NH 3 with SO 2 and NO X allowed concluding on the causes responsible for the variations in NH 3 levels between measurement periods observed in Barcelona, Huelva and Madrid. However, the factors governing the variations in A Coruña, Valencia and Santa Cruz de Tenerife are still not fully understood. This study identified a broad variability in NH 3 concentrations at the city-scale, and it confirms that NH 3 sources in Spanish urban environments are vehicular traffic, biological sources (e.g. garbage containers), wastewater treatment plants, solid waste treatment plants and industry. The importance of NH 3 monitoring in urban environments relies on its role as a precursor of secondary inorganic species and therefore PM X . Further research should be addressed in order to establish criteria to develop and implement mitigation strategies for cities, and to include urban NH 3 sources in the emission inventories. [ABSTRACT FROM AUTHOR]

Abstract: The chemical composition of size-segregated particulate matter (PM) was studied during summer and winter sampling campaigns, at two different urban sites (roadside and urban background) in the city of Madrid, Spain. PM was sampled with high volume cascade impactors, in 4 size ranges: 10–2.5, 2.5–1, 1–0.5 and <0.5μm. The carbonaceous content (OC and EC) was determined by a thermo-optical method, whilst the water soluble ionic species were measured by ion chromatography. The most common synoptic meteorological situations, including those causing the transport of African dusty air masses, were identified in both seasons. Whether the PM10 mass or the highest concentrations of EC and OC were found predominantly in the ultrafine size fraction at both sites. In contrast with roadside, at the urban background, the particle mass concentrations for the different size ranges were statistically higher in summer than in winter. Observed inter-site differences suggest the existence of other sources and formation processes contributing in the summer period to the levels of PM at the urban background site apart from road traffic emissions. Secondary organic carbon (SOC) showed a clear seasonal pattern, with much higher concentrations in summer than in winter in both places, as well as higher relative contributions at the urban background than at the road traffic site. (NH4)2SO4 levels were at their maximum at both sites in summer in PM0.5. Differently, higher values were reached in winter for NH4NO3 in PM0.5 and for NaCl in PM2.5–10. From the ion balances, it was observed that, in summer, the formation of secondary inorganic compounds included an unusual enrichment in Ca2+ in the submicrometre fraction, either at roadside or at urban background. [Copyright &y& Elsevier]

Abstract: Madrid, the largest city of Spain, has some and unique air pollution problems, such as emissions from residential coal burning, a huge vehicle fleet and frequent African dust outbreaks, along with the lack of industrial emissions. The chemical composition of particulate matter (PM) was studied during summer and winter sampling campaigns, conducted in order to obtain size-segregated information at two different urban sites (roadside and urban background). PM was sampled with high volume cascade impactors, with 4 stages: 10–2.5, 2.5–1, 1–0.5 and <0.5μm. Samples were solvent extracted and organic compounds were identified and quantified by GC-MS. Alkanes, polycyclic aromatic hydrocarbons (PAHs), alcohols and fatty acids were chromatographically resolved. The PM1–2.5 was the fraction with the highest mass percentage of organics. Acids were the organic compounds that dominated all particle size fractions. Different organic compounds presented apparently different seasonal characteristics, reflecting distinct emission sources, such as vehicle exhausts and biogenic sources. The benzo[a]pyrene equivalent concentrations were lower than 1ngm−3. The estimated carcinogenic risk is low. [Copyright &y& Elsevier]

Abstract: The majority of the Spanish urban population breathe air containing inhalable ambient airborne particles at average concentrations of 30–46μgm−3 (PM10) and 20–30μgm−3 (PM2.5). Even though the average weight of inhaled urban aerosol is commonly similar, however, there can be large chemical differences between the ambient dusts from different towns, including the more bioreactive elements such as some metals. In this context, we compare the source-apportioned trace metal content of airborne PM10 and PM2.5 collected daily over a 1-year period from six population centres in Spain: Barcelona, Alcobendas, Llodio, Huelva, Tarragona and Las Palmas de Gran Canaria. Total average trace metal (ΣTM) PM10 and PM2.5 contents vary by up to a factor of around 3, reaching a maximum of ΣTM10 811ngm−3 and ΣTM2.5 503ngm−3 at Llodio, an industrial but humid site with the lowest PM10 mass levels but high contamination by Zn, Pb, Mn, Sn, Ni and Cr. In contrast, pollution at Huelva, although another industrially influenced site, instead emphasises Cu and As, whereas Barcelona, where traffic emissions and resuspension contribute to some of the highest average PM10 levels in Spain, has unusually raised levels of Ti, V and Ba. Such variations in both daily and annual average PM bulk chemistry, particularly in potentially toxic trace metals concentrated in the finer aerosols (such as Cd, As, Pb, Hg and Ni), predict that PM health effects on resident populations from different towns are unlikely to be the same. [Copyright &y& Elsevier]

Background: Few recent studies examined acute effects on health of individual chemical species in the particulate matter (PM) mixture, and most of them have been conducted in North America. Studies in Southern Europe are scarce. The aim of this study is to examine the relationship between particulate matter constituents and daily hospital admissions and mortality in five cities in Southern Europe., Methods: The study included five cities in Southern Europe, three cities in Spain: Barcelona (2003-2010), Madrid (2007-2008) and Huelva (2003-2010); and two cities in Italy: Rome (2005-2007) and Bologna (2011-2013). A case-crossover design was used to link cardiovascular and respiratory hospital admissions and total, cardiovascular and respiratory mortality with a pre-defined list of 16 PM10 and PM2.5 constituents. Lags 0 to 2 were examined. City-specific results were combined by random-effects meta-analysis., Results: Most of the elements studied, namely EC, SO4(2-), SiO2, Ca, Fe, Zn, Cu, Ti, Mn, V and Ni, showed increased percent changes in cardiovascular and/or respiratory hospitalizations, mainly at lags 0 and 1. The percent increase by one interquartile range (IQR) change ranged from 0.69% to 3.29%. After adjustment for total PM levels, only associations for Mn, Zn and Ni remained significant. For mortality, although positive associations were identified (Fe and Ti for total mortality; EC and Mg for cardiovascular mortality; and NO3(-) for respiratory mortality) the patterns were less clear., Conclusions: The associations found in this study reflect that several PM constituents, originating from different sources, may drive previously reported results between PM and hospital admissions in the Mediterranean area., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Source apportionment study was performed, applying principal component analysis to the results of 221 chemical analyses of PM10 and PM2.5 samples collected daily from the industrial (but low traffic) Spanish town of Puertollano over a 14-month period during 2004-2005. Results reveal compositional variations attributable to different mixtures of natural and anthropogenic materials, mainly soil and rock dust (crustal), marine salt (only in PM10), petrochemical refinery emissions, and particles attributed to the combustion of local coal, which is unusually rich in Pb and Sb. During the study period there were 34 pollution episodes when PM10 exceeded 50 tg m(-3), mostly due to winter air temperature inversions, regional atmospheric stagnation, or African dust incursions (North African, NAF days: usually in summer). Whereas the crustal component during NAF episodes averaged 52% with a PM2.5/PM10 ratio of 0.54, this dropped to 29% and a PM2.5/PM10 of 0.67 during non-NAF days when anthropogenic materials predominated. Abnormally enhanced concentrations of pathfinder metallic trace elements provide additional evidence for source apportionment: thus aerosols with raised levels of Pb and Sb are associated with local coal combustion, Ni and V can be linked to petrochemical PM emissions, and Ti, Mn, Rb, and Ce are particularly characteristic of crustal dust incursions.