Fly for activation pollutant gas retention

[EN] Zeolites synthesized from fly ash by Hydrothermal Activation and Microwave Assistance were studied to evaluate their utilization as sorbents of pollutant gases like CO2, SO2, NH3. Fly ash have a high alumino-silicate content in its composition that makes it a good starting material to synthesize zeolites, getting efficiencies about 75%. Zeolites obtained by Hydrothermal Activation and Microwave Assistance were very similar. Depending on the synthesis parameters - reaction time, temperature and activation solution concentration- the following zeolites were obtained: Analcime, Sodalite, F-Linde, NaPl-zeolite and Chabazite. Synthesis yields and zeolite types obtained from the microwave and conventional experiments were very similar, but the activation time needed was drastically reduced by using microwaves (from 24-48 h to 10-30 min). The zeolitic material was previously activated at 473 K to remove the hydratation water and facilitate the gas adsorption. The adsorption experiments were performed at atmospheric pressure by flowing a mixture of every gas in He through the sample. The adsorption temperatures were 195 K (CO2), 263 K (SO2) and 250 K (NH3). The desorption experiments were made at room temperature. Finally, the effect of the substitution of Na+ by NH4+ in the NaPl-zeolite in the adsorption capacity was studied. The adsorption capacities obtained for all the samples were low. Only external surface of the zeolites was reached in the working conditions. In general, samples synthesized by microwave assistance showed more adsorption capacity than those synthesized by conventional methods.[ES] Se han estudiado las zeolitas sintetizadas a partir de cenizas volantes, mediante activación alcalina y calentamiento por vía hidrotermal o con microondas, con el objeto de evaluar su posible utilización como adsorbentes de gases contaminantes tales como CO2, SO2 Y NH3. Las cenizas volantes contienen un alto contenido en aluminosilicatos en su composición, por lo que pueden constituir una materia prima para llevar a cabo la síntesis de zeolitas, consiguiéndose en el mejor de los casos eficacias del 75%. Los tipos de zeolitas obtenidos por el método convencional y por microondas fueron muy similares, habiéndose sintetizado zeolitas sódicas y potásicas como Analcima, Sodalita, Linde F. NaPl, KM y Chabazita, dependiendo de los parámetros de síntesis (tiempo, temperatura y concentración y naturaleza del agente activante). La principal diferencia entre ambos métodos es el tiempo de activación necesario que se reduce considerablemente usando microondas hasta 30 minutos frente a las 24-48 h en el calentamiento convencional. Las zeolitas fueron previamente activadas a 473 K con la finalidad de eliminar parte del agua de constitución que contienen pero sin alterar su estructura, facilitando de este modo la posible adsorción gaseosa. Los experimentos de adsorción se llevaron a cabo a presión atmosférica, haciendo pasar mezclas de cada gas en Helio sobre la muestra y utilizando temperaturas de 195 K para CO2, 263 K para SO2 y 250 K para NH3. Las desorciones fueron realizadas a temperatura ambiente. Se ha estudiado también el efecto que produce el intercambio de Na+ de una zeolita (NaPl) por NH4 + en cuanto a la modificación de la capacidad de retención de gases. La capacidad de retención de gases fue baja para todas las zeolitas ensayadas. En las condiciones de trabajo utilizadas, únicamente la superficie externa de la zeolita es aprovechada para la adsorción. En general las zeolitas sintetizadas mediante microondas muestran mayor capacidad de retención de gases que las sintetizadas mediante el método convencional.Los autores desean agradecer a la Comisión Internacional de Ciencia y Tecnología (CICYT) y a la Comisión Europea para el Carbón y el Acero (CECA) las subvenciones económicas recibidas a través de los Proyectos AMB95-0198 y 7220-ED-079 respectivamente, para la realización de este trabajo.Peer reviewe

From air quality to climate: Impact of aerosol sources on optical properties at urban, regional and continental levels in the north-western Mediterranean

Further research is needed to reduce the existing uncertainties on the effect that specific aerosol sources have on radiative forcing, thus supporting the assessment of future mitigation strategies which should be focused on both air quality and climate, and not acting separately. This study presents a new approach aimed at quantifying the mass scattering and absorption efficiencies (MSE and MAE) of different aerosol sources at urban (Barcelona-BCN), regional (Montseny-MSY) and remote (Montsec-MSA) background sites in the northwestern (NW) Mediterranean. An analysis of source apportionment to the measured scattering and absorption coefficients was performed by means of a multilinear regression (MLR) model during 2010–2014 at BCN and MSY and during 2011–2014 at MSA. The source contributions to PM10 mass, identified by means of the Positive Matrix Factorization (PMF) model, were used as dependent variables in the MLR model in order to take into account the internal mixing state of atmospheric aerosols. Seven aerosol sources were obtained at MSA and MSY and 8 sources at BCN. Mineral, Aged marine, Ammonium sulfate, Ammonium nitrate and V-Ni bearing sources were common at the three sites. Traffic, Industrial/metallurgy and Road-resuspension were isolated at BCN, whereas Industrial/Traffic and Aged organics were solely identified at MSY and MSA. The highest MSE were found for Ammonium sulfate (4.5 and 10.7 m2 g−1), Ammonium nitrate (8.8 and 7.8 m2 g−1) and V-Ni (8 and 3.5 m2 g−1) at MSY and MSA respectively, dominating the scattering throughout the year with marked seasonal trends. V-Ni bearing, originated mainly from shipping emissions, simultaneously contributed to both scattering and absorption being the second most efficient absorptive source in BCN (0.9 m2 g−1). The Traffic source at BCN and the equivalent Industrial/Traffic at MSY and MSA mainly governed the light absorption and exhibited the highest MAE (1.7, 0.9 and 0.2 m2 g−1, respectively). Sources predominantly composed by fine and relatively dark particles such as Industrial/Traffic, Aged organics and V-Ni were simultaneously characterized with low single scattering albedo (SSA) and high scattering Angstrom exponent (SAE). Conversely, Mineral and Aged marine showed the highest SAE and the lowest SSA, being scattering the dominant process in the light extinction. The good agreement between modeled and measured optical properties allowed for the reconstruction of scattering, absorption and SSA time series by means of the PMF-MLR technique for the period 2004–2014 at MSY. Significant decreasing trends were found for the modeled scattering and absorption (−4.6 and −4.1 % y−1) coefficients. Interestingly, the observed reduction in the SSA (−0.11 % y−1) might suggests a less effectiveness of the air quality strategies focused on reducing pollutants containing black carbon (BC) particles, which highly contribute to light absorption and thus climate warming.This work was supported by the MINECO (Spanish Ministry of Economy and Competitiveness) and FEDER funds under the PRISMA project (CGL2012-39623-C02/00), by the MAGRAMA (Spanish Ministry of Agriculture, Food and Environment) and by the Generalitat de Catalunya (AGAUR 2014 SGR33 and the DGQA). This work has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 654109. Marco Pandolfi is funded by a Ramón y Cajal Fellowship (RYC-2013-14036) awarded by the MINECO. The authors would like to express their gratitude to D. C. Carslaw and K. Ropkins for providing the OpenAir software used in this paper (Carslaw and Ropkins, 2012; Carslaw, 2012).Peer reviewe

Copper aerosols inhibit phytoplankton growth in the Mediterranean Sea

Aerosol deposition plays an important role in climate and biogeochemical cycles by supplying nutrients to the open ocean, in turn stimulating ocean productivity and carbon sequestration. Aerosol particles also contain elements such as copper (Cu) that are essential in trace amounts for phytoplankton physiology but which can be toxic at high concentrations. While the toxicity of Cu associated with aerosols has been demonstrated in bioassay experiments, extrapolation of these laboratory results to natural conditions is not straightforward. This study provides observational evidence of the negative effect of aerosols containing high Cu concentrations on marine phytoplankton over a vast region of the Western Mediterranean Sea. Direct aerosol measurements were combined with satellite observations, resulting in the detection of significant declines in phytoplankton biomass after atmospheric aerosol events characterized by high Cu concentrations. The declines were more evident during summer, when nanoflagellates predominate in the phytoplankton population and stratification and oligotrophic conditions prevail in the study region. Together with previous findings concerning atmospheric Cu deposition, these results demonstrate that the toxicity of Cu-rich aerosols can involve large areas of the world’s oceans. Moreover, they highlight the present vulnerability of oceanic ecosystems to Cu-rich aerosols of anthropogenic origins. Since anthropogenic emissions are increasing, largescale negative effects on marine ecosystems can be anticipatedPeer Reviewe

Trends of particulate matter (PM₂.₅) and chemical composition at a regional background site in the Western Mediterranean over the last nine years (2002-2010)

The time variability and long term trends of PM₂.₅ (particulate matter of diameter <2.5 μm) at various regional background (RB) sites across Europe are studied and interpreted in this work. Data on mean annual levels of PM₂.₅ measured at Montseny (MSY, North East Spain) and various RB sites in Spain and Europe are evaluated and compared, and subsequently analysed for statistically significant trends. The MSY site registered higher average PM₂.₅ levels than those measured at a selection of other RB sites across Spain, Portugal, Germany and Scandinavia by percentage compared to the mean of all the stations in these countries, but lower than those measured in Switzerland, Italy and Austria. Reductions in PM₂.₅ were observed across all stations in Spain and Europe to varying degrees (7-49%). MSY underwent a statistically significant reduction since measurements began, indicating a year-on-year gradual decrease (−3.7 μgm¯³, calculated from the final year of data compared to the mean). Similar trends were observed in other RB sites across Spain (−1.9 μgm¯³). Reductions recorded in PM₂.₅ across Europe were varied, with many experiencing gradual, year-on-year decreases (−1.8 μgm¯³). These reductions have been attributed to various causes: the introduction and implementation of pollution abatement strategies in EU member states, the effect of the current economic crisis on emissions of PM₂.₅ and the influence of meteorology observed during the winters of 2009 and 2010. In addition, the North Atlantic Oscillation (NAO), a large scale meteorological phenomenon most prevalent during winter, was observed to influence the frequency of Saharan dust intrusions across the Iberian Peninsula. Chemical composition of PM₂.₅ at MSY is characterised by high levels of organic matter (OM) and sulphate, followed by crustal material, nitrate and ammonia. Sea Spray and elemental carbon (EC) comprised a minor part of the total PM₂.₅ mass. Statistical trend analysis was performed on the various chemical components of PM₂.₅ recorded at MSY to determine which components were accountable for the decrease in PM₂.₅ concentration. It is shown that OM underwent the largest decrease over the time period with a statistically significant trend (−1.3 μgm¯³ compared to the mean), followed by sulphate (−0.8 μgm¯³), ammonium (−0.5 μgm¯³) and nitrate (−0.4 μgm¯³). Conversely, sea spray, EC and crustal a material reductions were found to be negligible

Source apportionment of fine PM and sub-micron particle number concentrations at a regional background site in the western Mediterranean: a 2.5 year study

The chemical composition and sources of ambient fine particulate matter (PM₁) over a period of 2.5 years for a regional background site in the western Mediterranean are presented in this work. Furthermore, sub-micron particle number concentrations and the sources of these particles are also presented. The mean PM₁ concentration for the measurement period was 8.9 μgm¯³, with organic matter (OM) and sulphate comprising most of the mass (3.2 and 1.5 μgm¯³ respectively). Six sources were identified in PM₁ by Positive Matrix Factorisation (PMF): secondary organic aerosol, secondary nitrate, industrial, traffic + biomass burning, fuel oil combustion and secondary sulphate. Typically anthropogenic sources displayed elevated concentrations during the week with reductions at weekends. Nitrate levels were elevated in winter and negligible in summer, whereas secondary sulphate levels underwent a contrasting seasonal evolution with highest concentrations in summer, similar to the fuel oil combustion source. The SOA source was influenced by episodes of sustained pollution as a result of anticyclonic conditions occurring during winter, giving rise to thermal inversions and the accumulation of pollutants in the mixing layer. Increased levels in summer were owing to higher biogenic emissions and regional recirculation of air masses. The industrial source decreased in August due to decreased emissions during the vacation period. Increases in the traffic + biomass burning source were recorded in January, April and October, which were attributed to the occurrence of the aforementioned pollution episodes and local biomass burning emission sources, which include agriculture and domestic heating systems. Average particle number concentrations (N₉_₈₂₅ nm) from 5/11/2010 to 01/06/2011 and from 15/10/2011 to 18/12/2011 reached 3097 cm¯³. Five emission sources of particle of sub-micron particles were determined by Principal Component Analysis (PCA); industrial + traffic + biomass burning, new particle formation + growth, secondary sulphate + fuel oil combustion, crustal material and secondary nitrate. The new particle formation + growth source dominated the particle number concentration (56% of total particle number concentration), especially for particles 100 nm) and thus did not influence the particle number concentration significantly

Detection of the Saharan dust air layer in the North Atlantic free troposphere with AERONET, OMI and in-situ data at Izaña Atmospheric Observatory

Comunicación presentada en: Symposium on Atmospheric Chemistry and Physics at Mountain Sites celebrado del 8 al 10 de junio de 2010 en Interlaken, Suiza

Element behaviour during combustion in coal-fired Orhaneli power plant, Bursa-Turkey

This study focuses on element behaviour during combustion in the Orhaneli thermal power plant (a 210 MW unit, Bursa-Turkey). A total of 51 samples, feed coals (FCs), fly ashes (FAs) and bottom ashes (BAs), which were systematically collected over an eight-week period, have been analysed for major, minor and trace elements (Al, Ca, Fe, K, Mg, Na, S, As, B, Ba, Be, Bi, Cd, Co, Cr, Cs, Cu, Ga, Ge, Hf, Hg, Li, Mn, Mo, Nb, Ni, P, Pb, Rb, Sb, Sc, Se, Sn, Sr, Ta, Th, Ti, Tl, U, V, W, Y, Zn, Zr and REEs). This study shows that FCs on an airdried basis have high moisture (av. 9%), high volatile matter (av. 33%), very high ash yield (av. 53%), relatively high sulfur content (av. 2.14%) and low gross calorific value (av. 1775 kcal/kg). Proximate analyses of combustion residues imply that BAs have higher contents of unburned carbonaceous matter than FAs. Mean values of trace element concentrations in FCs fall within the ranges of most world coals, except for Cr, Cs, Ni and U which occur in concentrations slightly higher than those determined for most of world coals. Some elements such as S, Hg, As, B, Bi, Cd, Cs, Ge, K, Pb, Rb, Sb, Se, Sn, Tl, and Zn are indicating enrichments in FAs. The remaining elements investigated in this study have no clear segregation between FAs and BAs. The mass balance calculations point to Ca content of feed coal controlling the partitioning of elements in this power plant, producing a high removal efficiency for highly volatile elements such as Hg, B and Se, and a high retention of As, Bi, Cd, Cs, Ge, Pb, Rb, Sb, Sn, Tl and Zn in FAs. However, the high enrichment in trace elements of FAs can increase the hazardous potential of this coal by-product

Concentrations, sources and geochemistry of airborne particulate matter at a major European airport

9 pages, 9 figures, 2 tables.-- PMID: 20383366 [PubMed]Monitoring of aerosol particle concentrations (PM10, PM2.5, PM1) and chemical analysis (PM10) was undertaken at a major European airport (El Prat, Barcelona) for a whole month during autumn 2007. Concentrations of airborne PM at the airport were close to those at road traffic hotspots in the nearby Barcelona city, with means measuring 48 g PM10/m3, 21 g PM2.5/m3 and 17 g PM1/m3. Meteorological controls on PM at El Prat are identified as cleansing daytime sea breezes with abundant coarse salt particles, alternating with nocturnal land-sourced winds which channel air polluted by industry and traffic (PM1/PM10 ratios > 0.5) SE down the Llobregat Valley. Chemical analyses of the PM10 samples show that crustal PM is dominant (38% of PM10), followed by total carbon (OC + EC, 25%), secondary inorganic aerosols (SIA, 20%), and sea salt (6%). Local construction work for a new airport terminal was an important contributor to PM10 crustal levels. Source apportionment modelling PCA-MLRA identifies five factors: industrial/traffic, crustal, sea salt, SIA, and K+ likely derived from agricultural biomass burning. Whereas most of the atmospheric contamination concerning ambient air PM10 levels at El Prat is not attributable directly to aircraft movement, levels of carbon are unusually high (especially organic carbon), as are metals possibly sourced from tyre detritus/smoke in runway dust (Ba, Zn, Mo) and from brake dust in ambient PM10 (Cu, Sb), especially when the airport is at its most busy. We identify microflakes of aluminous alloys in ambient PM10 filters derived from corroded fuselage and wings as an unequivocal and highly distinctive tracer for aircraft movement.This work was supported by research projects from the Spanish Ministry of Environment (MMA 2006_EG0X2006-M-PARTICULADO- M1) (CALIOPE, 441/2006/3-12.1), the Spanish Ministry of Sciences and Innovation (GRACCIE-CSD2007- 00067, DOASUR CGL2007-62505/CLI) and a fellowship from the Spanish Council of Research (CSIC).Peer reviewe

Unlinking summer new particle formation and high ozone episodes

New particle formation (NPF) and ozone (O3) episodes are products of photochemically-driven processes. However, O3 formation occurs under the presence of precursors (Monks et al., 2015), whereas NPF usually requires clean atmospheres (Boy and Kulmala, 2002). Clustering studies on particle number size distribution (PNSD) time series in high insolation urban areas revealed the frequent occurrence of photochemical NPF in spring and summer (Brines et al., 2015). Averaged O3 concentrations reached the highest concentrations for the NPF-cluster in most of the studied cities. We intend here to elucidate if this simultaneous peaking of NPF and O3 is due to the similar seasonal patterns of both pollutants or because NPF episodes coincide with high O3 episodes. To this end we analyzed 2014-2018 spring and summer time series of PNSD and O3 concentrations at Montseny, a regional background station 40 km NE of Barcelona (Spain) included in the ACTRIS and GAW networks.We categorized NPF events with the method proposed by (Dal Maso et al., 2005). K-means clustering was applied to the O3 daily series. The number of clusters was chosen so that only one clusters contained all the days registering an exceedance of the information value (180 μg m-3 h-1), using the minimum number of clusters. This was achieved by using 4 clusters. For each of them we studied the occurrence of NPF and the average daily cycles of other variables: PNSD, concentration of NO2, SO2, and PM1, and meteorological variables. The results suggest that, for spring and summer, the highest regional background UFPs concentrations coincide with the highest O3 episodes, but the probability of NPF during these days is the lowest, even though the nucleation-mode number concentration is the highest. These days also present the maximum temperature, solar radiation, and wind speed, and the lowest relative humidity. The condensation sink and concentration of other pollutants are also the highest and peak simultaneously with the wind speed. This suggests that during these days pollutants are transported from the Barcelona metropolitan area to the regional background station. Conversely, when the plume does not reach the station, UFPs and O3 concentrations are the lowest, and the probability of NPF is the highest