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Microplastics have appeared as emerging pollutants due to the diverse applications of plastics in today's world. Growing evidence points to the negative impacts that airborne microplastics have on human health, as they can enter the human body through respiration. Our aim was to quantify polystyrene airborne microplastics in smaller fractions, thoracic (PM

A mixture of supermarket food waste from bakery, butchery, cooked meats and cheese, fishmonger, fruit, and vegetable sections was subjected to anaerobic digestion under thermophilic conditions (55 °C). Lab-scale induced bed reactors (IBR) and completely stirred tank reactors (CSTR) were operated at different organic loading rates (OLR), i.e., 3.0, 3.6 and 4.6 kg volatile solids (VS) per m3 of reactor and day. Regardless of the type of reactor, an OLR of 3.6 kg VS/m3·day was found to be the optimum, achieving up to 48.1% more methane production per kg of treated waste than for the other OLRs tested. In general, there were no statistically significant differences (p-value Finally, the process was successfully tested under large-scale conditions (1.25 m3 IBR pilot-plant). The CH4 production and the biodegradation yield were in line with those obtained in the lab-scale IBR.

The methane potential of supermarket food waste (SMW) has scarcely been determined, especially at 55 °C. In this paper, the different types of SMW generated in a chain of supermarkets have been characterized over a period of 1 year. Batch anaerobic digestion tests employing six different mixtures of SMW were conducted under thermophilic conditions. Start-up was very rapid, with lag-phase values

The rationale of this paper was to investigate whether earthquakes impact airborne pollen concentrations, considering some meteorological parameters. Atmospheric pollen concentrations in the Region ofMurcia Aerobiological Network (Spain)were studied in relation to the occurrence of earthquakes ofmoment magnitude (up toMw=5.1) and intensity (intensity up to grade VII on the European Macroseismic Scale). In this study, a decade (2010–2019) was considered across the cities of the network. Earthquakes were detected in 12 out of 1535 days in the Olea Main Pollen Season in Cartagena, 49 out of 1481 days in the Olea Main Pollen Season in Lorca, and 39 out of 1441 days in the Olea Main Pollen Season in Murcia. The Olea pollen grains in this network were attributed to the species Olea europaea, i.e., the olive tree, a taxon that appears widely in the Mediterranean basin, in both cultivated and wild subspecies. Differences between the Olea concentration on days with and without earthquakes were only found in Lorca (Kruskal-Wallis: p-value=0.026). The low frequency and intensity of the earthquakes explained these results. The most catastrophic earthquake felt in Lorca on May 11th, 2011 (IVII, Mw=5.1, 9 casualties) did not result in clear variations in pollen concentrations, while meteorology (e.g., African Dust Outbreak) might have conditioned these pollen concentrations. The research should be broadened to other active seismological areas to reinforce the hypothesis of seismological impact on airborne pollen concentrations. This research was funded by the Ministry of Science and Innovation of the Spanish Government, grant number SICAAP-CPI RTI2018-096392-BC21; the Interministerial Committee of Science and Technology, grant numbers BOS2000-0563-C02-02, BOS2003-06329-C02-02, and BOS 2006-15103; and the Seneca Foundation of the Region of Murcia, grant number 08849/PI/08. The anonymous reviewers are thanked for their comments to improve the quality of the manuscript. The authors wish to express their gratitude to Dr. Belén Elvira-Rendueles for her advice and commitment with REAREMUR and, Ms. Paula García López, technician at REAREMUR, funded by the Spanish State Research Agency, Ministry of Science, Innovation and Universities (code: PTA2017-13571-I). Authors thank NOAA for providing the synoptic charts, AEMET for the meteorological data and IGN for the seismological information. Gratitude is also shown to Laura Wettersten for the language edition.

The evolution of the behaviour of the Cannabis taxon in the Region of Murcia, Spain, has been analysed (in the cities of Cartagena, 1993-2020; Murcia, 2010-2020; and Lorca, 2010-2020). An attempt has been made to establish the origin of Cannabis pollen in this region to determine whether it is transported locally or from long distances based on air mass origins. Cannabis is an herbaceous, normally dioecious and anemophilous plant, which produces large quantities of pollen grains. It has been widely used for fibre (hemp), bird food (hempseed), essential oils and narcotics. The origin of Cannabis pollen grains has been established by calculating back trajectories at the altitudes of: 750, 1500 and 2500 m above mean sea level (m amsl); 350, 500 and 650 m amsl; and 10, 100 and 250 m amsl, using the HYSPLIT model. Considering this data, 29 days of Cannabis pollen potentially originating in Africa were identified in Cartagena, 19 days in Murcia and 15 days in Lorca. Of the remaining days, the air mass back trajectories showed local or regional pollen origins. These were 83 days in Cartagena, 61 days in Murcia and 57 days in Lorca. The presence of Cannabis in the bioaerosol of the Region of Murcia is irregular, and it is considered a minority pollen type. However, from 2017 to 2020, concentrations increased, with a positive and significant trend of 90% in the Annual Pollen Integral. The pollen season can be defined between June and August. This increase in the concentration of Cannabis pollen grains during this period coincides with an increase in local transport, suggesting the possibility of increased Cannabis cultivation in the study area.

Airborne particulate matter such as mineral dust comes mainly from natural sources, and the arid regions of Sahara and Sahel in Africa release large amounts of the aerosols dispersed worldwide. There is evidence of concomitant presence of desert dust particles and bioaerosols such as pollen grains in the atmosphere, which produce a significant decline in air quality during the dust intrusions events. However, there is little knowledge about the influence of dust episodes on pollen exposure in allergy sufferers as well as the causes that may produce a potential effect of the intrusions on airborne pollen levels. This potential effect on the airborne pollen concentrations is analysed in the Iberian Mediterranean region in this study. Mediterranean countries are strongly affected by Saharan-Sahel dust intrusions, and the Iberian territory, specially the central and southern areas, suffer frequently great incidence of dust episodes due to its geographic location. In this study firstly, the simultaneous occurrence between airborne pollen peaks and Saharan-Sahel dust intrusions were analysed and compared with the behaviour in the days before and after the dust intrusions in the central and south-eastern Iberian Peninsula. Secondly, the weather conditions favouring high pollen concentrations during dust episodes namely prevalent winds, air mass pathways and variations in other meteorological variables like air temperature, relative humidity or atmospheric pressure were studied.Pollen peaks often coincided with dust episodes during the pollen season in the central Iberian Peninsula. The increase of the airborne pollen concentrations during the dust episodes is clear in inland Iberian areas, although this was not the case in coastal areas of the southeast where pollen concentrations could even be seen to decrease when easterly winds from the sea prevailed during dust intrusions. Total pollen concentrations and also pollen types such as Olea, Poaceae and Quercus showed an increase in the central Iberian Peninsula during the dust episodes when two meteorological phenomena occurred simultaneously: 1) prevailing winds came from large areas of the main wind-pollinated pollen sources at medium or short scale (mainly from western and southwestern areas); and 2) optimal meteorological conditions that favoured pollen release and dispersal into the atmosphere (mainly high temperatures and low humidity). Both these conditions often occur during Saharan-Sahel dust intrusions in the centre. The findings suggest that the proportion of long-range transport is lower than those produced in medium and short distance by dust intrusions of air masses. Therefore, maximum pollen peaks are most likely to occur during dust episodes in the central Iberian Peninsula dramatically increasing the risk of outbreaks of pollinosis and other respiratory diseases in the population. The negative effects of the mineral dust on public health are well known, even more so when allergenic biological agents are co-transported together by the air mass movements coming from desert areas. The findings of this study have very relevant implications for defining health-emergency alerts for severe Saharan-Sahel dust outbreaks.

Olea pollen concentrations have been studied in relation to the typology of air masses, pollen grain sources and marine nature during advections in a coastal enclave in the south-eastern Iberian Peninsula. Since Spain is the world's leading olive producer, and olive growing extends throughout the Mediterranean basin, this location is ideal for the study of long-distance transport events (LTD) during the main pollen season (MPS). The air masses were classified using the calculation of 48-h back trajectories at 250, 500 and 750 m above ground level using the HYSPLIT model. After that, the frequency of LDT events from Africa and Europe was found to be 8.7% of the MPS days. In contrast, regional air masses were found in 38.6% of the MPS days. This was reflected in pollen concentrations, with significantly higher concentrations (p-value

Settleable particulate matter (SPM) was collected at two sampling points within an urban area highly affected by nearby industrial activities. Total deposition values up to 386 mg ·m−2·d−1 were registered, the majority of samples exceeding the limit value established in the legislation in force in Spain until 2002 (300 mg·m−2·d−1). Dry deposition values showed high variability (8.6–830.3 mg·m−2·d−1). Forty-one metals and metalloids were analysed in the dry fraction of SPM, the main being Fe and Ca (maximums: 304.4 and 68.6 mg·m−2·d−1, respectively), followed by Al, Mg, Na, K, Mn, Ti, P and Zn. Trace elements like As and Pb reached up to 7.3 and 76.3 μg· m−2·d−1, respectively. Strong correlations (r > 0.90, p-value Furthermore, a human health risk study was carried out to assess the potential carcinogenic and non-carcinogenic risks of exposure to thirteen elements in these particles (Al, As, Cd, Co, Cu, Mn, Mo, Ni, Pb, Sb, Sr, V and Zn). The highest levels of risk seemed to be associated with the presence of As, Pb and Sb.

The aim of this study was to evaluate the enhancement of biogas production from cattle manure (CM) at pilot-plant scale using: a) ultrasound pretreatment (US) (520 kJ/kg Total Solids (TS); 409.59 kJ), b) co-digestion with crude glycerine (Gly) from the biodiesel industry (6% w/w), and c) US pretreatment (520 kJ/kg TS; 340.84 kJ), applied to the aforementioned mixture of both substrates prior to anaerobic co-digestion. The reactor used for this purpose was an Induced Bed Reactor (IBR), with a useful volume of 1250 L. Methane production from CM was enhanced by the application of low-energy ultrasound pretreatment (520 kJ/kg TS) (from 0.29 to 0.46 m3 CH4/kg Volatile Solids (VSadded)), and by co-digestion with Gly (from 0.29 to 0.44 m3 CH4/kg VSadded). The best results were obtained when the mixture of CM + Gly was pretreated by US (up to 0.59 m3 CH4/kg VSadded). Observation by Scanning Electron Microscopy (SEM) of the microstructural changes the CM underwent after pretreatment and/or co-digestion with crude glycerine enabled the discussion and justification of the results obtained in the present study.

This study investigates the human health risk of Al, As, Fe, Mn, Ni, Pb, Sb and Sr in the dry deposition fraction of settleable particulate matter (DSPM). Sixty samples were collected at an industrial suburban site (‘EMA’) and a waterfront urban site (‘Naval’) in Gijon, a coastal city in northern Spain. Up to 4898.4 mg·m-2·d-1 were measured at the station closer to industrial activity. The levels of the eight elements were greater at this site. Fe and Al were the major constituents, comprising up to 50% of DSPM. The human health risk posed by DSPM was assessed using a U.S.EPA methodology. The level of exposure to the metals/metalloids in this atmospheric pollutant was studied via ingestion, inhalation, and dermal contact. The results showed that ingestion was the main exposure pathway for the residents at the two locations, followed by dermal contact and inhalation. For adults, the non-carcinogenic hazard indexes and the carcinogenic risk levels of the eight elements were within the acceptable levels (1 and 10-5, respectively). Nevertheless, in the case of children, the non-carcinogenic hazard indexes of Fe and Pb as well as the carcinogenic risk level of As via ingestion were higher than those thresholds. Despite its importance, little research has focused on assessing the human risk posed by metals/metalloids in DSPM. Although there are uncertainties regarding the exposure factors and toxicity values, the outcomes of this study provide useful knowledge for regulatory authorities to establish appropriate mitigation measures to reduce DSPM emissions in urban and suburban environments.

Airborne particulate matter such as mineral dust comes mainly from natural sources, and the African regions of Sahara and Sahel originate large amounts of the aerosols dispersed worldwide. There is little knowledge about the influence of dust episodes on airborne pollen concentrations, and although the centre and southeast of the Iberian Peninsula are frequently affected by dust intrusions, until now, no specific works have analysed the effect of these episodes on airborne pollen concentrations in these areas. The aims of this study were to analyse the simultaneous occurrence of airborne pollen peaks and Saharan-Sahel dust intrusions in the central and south-eastern Iberian Peninsula, and to study the weather conditions – air mass pathways and conditions of air temperature, relative humidity and atmospheric pressure – that influence the airborne pollen concentrations during dust episodes. The results showed that the rise in airborne pollen concentrations during dust episodes is apparent in inland Iberian areas, although not in coastal areas in the southeast where pollen concentrations are even observed to decrease, coinciding with prevailing easterly winds from the sea. Total pollen concentrations and specific pollen types such as Olea, Poaceae and Quercus showed an increase in the central Iberian Peninsula during dust episodes when two meteorological phenomena concur: 1) prevailing winds from extensive areas of major wind-pollinated pollen sources over a medium or short distance (mainly from western and southwestern areas); and 2) optimal meteorological conditions that favour pollen release and dispersal into the atmosphere (mainly high temperatures and subsequently low humidity in central areas). Both conditions often occur during the Saharan-Sahel dust intrusions in the centre. Maximum pollen peaks are therefore most likely to occur during dust episodes in the central Iberian Peninsula, thus dramatically increasing the risk of outbreaks of pollinosis and other respiratory diseases in the population.

The Olea pollen is currently an important allergy source. In some regions of Southern Spain, olive pollen is the main cause of allergic sensitization exceeding 40% of the sensitized individuals. Due to the scarce presence of olive trees in Northern Spain, limited to some cultivated fields in the South of the Galicia region where they also grow wild, only 8% of the sensitized individuals showed positive results for Olea pollen. The aim of the paper was to assess the behaviour pattern of the Olea pollen and its aeroallergens in the atmosphere, as this information could help us to improve the understanding and prevention of clinical symptoms. Airborne Olea pollen and Ole e 1 allergens were quantified in Cartagena (South-eastern Spain) and Ourense (North-western Spain). A volumetric pollen trap and a Burkard Cyclone sampler were used for pollen and allergen quantification. The Olea flowering took place in April or May in both biometeorological sampling areas. The higher concentrations were registered in the Southern area of Spain, for both pollen and Ole e 1, with values 8 times higher for pollen concentrations and 40 times higher for allergens. An alternate bearing pattern could be observed, characterized by years with high pollen values and low allergen concentrations and vice versa. Moreover, during some flowering seasons the allergen concentrations did not correspond to the atmospheric pollen values. Variations in weather conditions or Long Distance Transport (LDT) processes could explain the discordance. The back trajectory analysis shows that the most important contributions of pollen and allergens in the atmosphere are coincident with air masses passing through potential source areas. The exposure to olive pollen may not be synonym of antigen exposure.

Thirty-two chemical species were determined in PM10 sampled at a suburban site on the north coast of Spain. Enrichment factors were applied to infer their soil/non-soil origin. The geochemical ratios were calculated using two databases: soil composition from locations in the surroundings of the sampling station and the Earth’s average upper-crust composition. In the present study, dissimilarities were found between the enrichment factors obtained using these two databases. Al, Ti, La and Ce were taken as the reference elements to normalise the data, reaching analogous conclusions. Bi, Cd, Cu, Sb, Se, Sn and Zn were associated with predominantly non-soil apportionments. As the relevance of soil/non-soil sources for the other analysed elements was found to be variable, they were probably of mixed origin. Furthermore, pairs of elements showed strong relationships, thus pointing to a common origin. Na–Mg and Co–Ni, with Pearson correlation coefficients above 0.9, were respectively related to marine and industrial apportionments. Enrichment factors have proved to be a useful tool to distinguish the soil/non-soil origin of chemical species present in airborne particulate matter. However, the choice of the reference database for soil composition considerably determined the accuracy of the conclusions.

There is growing interest in investigating the human health risk associated with metals in airborne particulate matter. The objective of this paper is the health risk assessment of Al, Be, Sb, Sn, Ti and Tl in PM10 under different advections of air masses. These metals/semi-metal were studied in samples collected in an area influenced by industrial activities in northern Spain with the aim of analysing the variations in PM10 metal/semi-metal. Elemental concentrations were assessed over a period of one year in terms of air mass origin by means of back trajectories (HYSPLIT), the conditional probability function, polar plots, PM concentration roses, aerosol maps (NAAPs) and receptor modelling. The mean concentrations of Al, Be, Sb, Sn, Ti and Tl were 254, 0.02, 1.30, 1.15, 15.3 and 0.20 ng/m3, respectively, and were within the usual range for suburban stations in Europe. The highest levels were recorded during conditions of regional air mass origin, highlighting the importance of sources not far from the station. Under these circumstances, the renovation of air masses was not produced. The main sources of metals were anthropogenic, mostly related to the use of coal and coke production. In general, the cancer and non-cancer risk values obtained in this study fell within accepted precautionary criteria in all trajectory groups. However, in order to improve air quality and reduce risks to human health, the impact resulting from the joint inhalation of Al, Be, Sb, Sn, Ti and Tl should not be ignored when air masses are fundamentally of regional origin.

Olive cultivation is of great importance in Southern Europe but olive pollen is the leading cause of allergy in many regions where it is grown. The best preventive measure for allergic patients is to avoid exposure. Thus, aerobiological monitoring networks must supply realistic pollen classes for the different types of allergic pollen. Even though those pollen classes are defined, they do not necessarily fit local data. Altogether, they should use predictive models to assess flowering intensity in advance. In this study, the Olea pollen degree of exposure classes (OPDEC) are defined based on percentiles and a predictive model is suggested for Cartagena, Spain. 24year (1993-2016) Olea pollen counts series was used to characterize the Main Pollen Season (MPS). The aerobiological samples were processed following the methodology proposed by Hirst and developed by the Spanish Aerobiology Network. The aerobiological database was completed with the meteorological data supplied by AEMET (Spanish State Meteorological Agency). MPS evolution over time, and its relation with temperature and rainfall, has been analysed. The study showed an increase in MPS duration and the amount of Olea pollen grains collected both in MPS and the peak day. The OPDEC should fit local data to improve preventive measures. Based on the 24year series, the proposed OPDEC for Cartagena are: Low (≤10grains/m3), Medium (between 10 and 50grains/m3), High (between 51 and 100grains/m3) and Very High (≥100grains/m3). Olea pollen estimations in the MPS and in the peak day were obtained by means of three Regression Methods and climatic factors. The analysis reveals that the Bagging for Regression Trees (BRT) method is a good predictive alternative and stablishes the importance for each meteorological variable.

The incidence of pollinosis in developed countries has been on the rise for the past few decades. It is an illness that leads to a large number of missed work and school days. Therefore, in addition to the direct costs associated therewith, it also causes significant indirect costs. Avoidance to exposure is the most effective preventive measure. With aerobiological data for homogeneous geographical areas, sick people can both take preventive measures and optimize the period of usage of drugs and thus improve the quality of their life. Aerobiological networks have to decide how to provide this information. In the case of information intended for the general public, it is more useful to give it as concentration ranges adjusted to categories of low, medium and high/very high threshold values than as specific numerical values, which might not achieve the desired goal.In this paper we have analyzed the data generated by the Aerobiological Network of the Region of Murcia, Spain, from aerobiological databases in the 2010-2016 period. Based on the analysis of the 90, 95, 97 and 99 percentiles of the time series, we have proposed threshold values —in four levels (low, medium, high and very high), for the Poaceae and Urticaceae pollen types in the towns of Cartagena, Lorca and Murcia— that enhance the information supplied by said Aerobiological Network and are aimed at allowing allergic people to take avoidance and pharmacological treatment measures. La prevalencia de la polinosis está aumentando en los países desarrollados en las últimas décadas, siendo una enfermedad que ocasiona un gran número de días de pérdida de actividad laboral o de asistencia a la escuela, por lo que, además de los costes directos ligados a la enfermedad, ocasiona importantes costes indirectos. La evitación de la exposición es la medida preventiva más eficaz. El disponer de datos aerobiológicos para áreas geográficas homogéneas permite a los enfermos, tanto poner en marcha medidas preventivas, como optimizar el periodo de uso de medicamentos y mejorar la calidad de vida. Las redes aerobiológicas deben decidir el modo en que suministra la información. En el caso de información destinada a la población general, es más útil difundirla como intervalos de concentraciones ajustados a categorías de valores umbrales bajos, medios, altos o muy altos, que a un dato numérico concreto que puede no alcanzar el objetivo perseguido.En este trabajo hemos analizado esta información para los datos generados en la Red Aerobiológica de la Región de Murcia y a partir de las bases de datos aerobiológicas del periodo 2010-2016 hemos propuesto, basado en el análisis de los percentiles 90, 95, 97 y 99 de la serie temporal, unos valores umbrales, en cuatro escalones, bajo, medio, alto y muy alto para los tipos polínicos Poaceae y Urticaceae en la ciudades de Cartagena, Murcia y Lorca, que mejoran la información suministrada por la Red Aerobiológica de la Región de Murcia encaminada a que los pacientes alérgicos emprendan las medidas de evitación y el tratamiento farmacológico. A prevalência da polinose tem vindo a aumentar nos países desenvolvidos nas últimas décadas, sendo uma doença que ocasiona um grande número de dias de absentismo laboral ou escolar, pelo que, além dos custos diretos associados à doença, determina consideráveis custos indiretos. Evitar a exposição é a medida preventiva mais eficaz. Dispor de dados aerobiológicos para áreas geográficas homogéneas permite aos doentes quer adotar medidas preventivas, quer otimizar o período do uso de medicamentos, melhorando a sua qualidade de vida. As redes aerobiológicas devem decidir a forma como disponibilizam a informação. No caso de informação destinada à população em geral é mais útil difundi-la como intervalos de concentrações ajustados a categorias de valores limite baixos, médios, altos ou muito altos, considerando que um dado numérico concreto pode não atingir o objetivo pretendido.Neste trabalho foi analisada esta informação para os dados gerados na Rede Aerobiológica da Região de Múrcia, já a partir das bases de dados aerobiológicas no período 2010-2016. Baseados na análise dos percentis 90, 95, 97 e 99 da série temporal, foram propostos valores limites, em quatro escalões (baixo, médio, alto e muito alto), para os tipos polínicos Poaceae e Urticaceae, nas cidades de Cartagena, Múcia e Lorca, visando melhorar a informação disponibilizada pela Rede Aerobiológica da Região de Múrcia, destinada a que os pacientes alérgicos empreendam medidas de redução da exposição e o tratamento farmacológico.

PM10 samples were collected at two suburban locations in northern Spain, a traffic-industrial suburban (TIS) station located in the coastal city of Gijon and an industrial suburban (IS) station in Langreo, about 25 km inland. The aerosol samples were chemically analysed to determine ambient air concentrations of As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Se, V and Zn. The results showed that the mean levels of As, Co, Cu, Fe, Mn, Ni, Pb and Se recorded at the IS location were higher than those at the TIS station. Mean levels of Fe and Zn in PM10 were higher than all other species at both the TIS and IS sampling sites (467 and 353 ng Fe/m3 and 46 and 282 ng Zn/m3, respectively). Human exposure to these twelve potentially toxic elements through PM10 was assessed for both children and adults using the U.S.EPA method, considering three pathways: ingestion, dermal contact and inhalation. In general, the IS location presented higher non-cancer risks than the TIS site. However, at both suburban locations, cancer and non-cancer risk values were in the acceptable range for adults, some exceptions being found. Greater health risk was estimated in the case of children. For this sector of the population, ingestion, dermal contact and/or inhalation of As, Pb and Zn in PM10 may pose a health hazard owing to possible carcinogenic/non-carcinogenic effects.

Species of the Amaranthaceae family are abundant in the Southeast of Spain, one of the driest areas in Europe. The Amaranthaceae include species of interest from the point of view of allergic diseases. With the expansion of aridity, many species belonging to this family will be favoured. The objectives of this study were: first, to define the prevalence of sensitization to Amaranthaceae pollen in allergic patients in the Southeast of Spain; second, to present the aerobiological features of this taxon; and, finally, to demarcate those periods of increased risk of suffering allergic symptoms with the aim of improving the diagnosis and prevention of hay fever. Skin prick tests with extracts of pollen were performed on patients with symptoms of respiratory allergy referred for consultation for the first time in Almeria and Murcia. Samples of the atmospheric bioaerosol were taken using a Lanzoni VPPS 2000 volumetric sampler, samples treatment and subsequent counts being carried out according to the methodology approved by the Spanish Aerobiological Network. The statistical significance of the correlation between aerobiological and meteorological data from this arid region in 2010–2014 was determined. The aerobiological study revealed the presence of two distinct peaks responsible for pollen symptoms. The flowering of this taxon is especially noteworthy in the city of Cartagena, where it supposes 94% of the total pollen collected in these periods. This situation converts Amaranthaceae pollen in the second leading cause of hay fever in the Southeast of Spain. With the expansion of aridity, an increase in the presence of these species is expected. Bearing in mind their prevalence in the spring and summer/autumn periods and their extensive presence in the bioaerosol, this makes data from Southeastern Spanish a benchmark with respect to the aerobiology of this type of pollen.

To increase the production of methane, when cattle manure (CM) is digested, pretreatments can be applied and/or the manure can be co-digested with other wastes. In this research work, a mixture of CM, food waste (FW) and raw glycerine (Gly) in a proportion in weight of 87% CM, 10% FW and 3% Gly was digested, (a) without pretreatment and (b) with pretreatment by ultrasound, applying a sonication energy of 1040 kJ/kg total solids. Specific methane production was 290 L CH4/kg volatile solids (VS) without pretreatment and 520 L CH4/kg VS with pretreatment. With respect to the volumetric methane production, 1.07 L CH4/Lreactor.day was produced in the first case, and in the second case, 1.98 L CH4/Lreactor.day. We can conclude that the application of ultrasound pretreatment significantly improved the production of biogas.

PM10 was sampled at a suburban location affected by traffic and industry in the north of Spain. The samples were analysed to determine the chemical components of PM10 (organic and elemental carbon, soluble chemical species and metals). The aim of this study was to assess the toxicity of PM10 in terms of the bulk analysis and the physico-chemical properties of the particles. Total carbon, sulphates, ammonium, chlorides and nitrates were found to be the major constituents of PM10. The contribution of the last of these was found to increase significantly with PM10 concentration (Pearson coefficient correlation of 0.7, p-value 0.001). Individual airborne particles were characterised morphologically and chemically via a combination of Scanning Electron Microscopy and Energy-Dispersive X-ray spectroscopy (SEM-EDX). The subsequent image analysis revealed C-rich particles with shapes that pointed to combustion processes. Moreover, carbonaceous particles seemed to act as vehicles for sulphur compounds and metals (S, Na, Fe, Ca, Mg, K, Al, Mn, Zn and Cu). Coarse particles were found to be mainly constituted by crustal material and marine and carbonaceous particles. Although most of the studied individual particles in PM10 samples (86.0%) had a diameter within the 0.1-2.5 μm range, 1.8% of them had sizes lower than 0.1 μm 40.2% of the total studied particles were estimated to be inhaled and deposited in the human respiratory tract; 12.3% of these particles would reach the deepest zones, thereby posing a major risk to human health.

African dust outbreaks over the Iberian Peninsula have been related to four synoptic patterns responsible for the advection of dust: 1. A North African high located at surface level. 2. An Atlantic depression centered over northwestern Africa, western Iberia or the southwest of the Portuguese coast with an associated high or ridge over the Mediterranean Sea. 3. A North African depression. 4. A North African high located at upper levels. Consequently, particulate matter (PM) levels in Iberia are expected to rise when any of these atmospheric synoptic scenarios prevail. Nevertheless, PM levels might not increase due to wet deposition, as Spain receives the most African-derived dust rain events of any European country. In this study, a meteorological scenario different than the above situations is evaluated.

The aim of this research study was to analyse the effect of applying inverted phase fermentation (IPF) prior to the anaerobic digestion of cattle manure and sewage sludge. IPF promotes the endogenous bacteria present in waste and hence enzymatic hydrolysis, producing a solid-liquid separation. The clarified bottom layer or liquid phase (LP, 70% volume in manure and 65% in sludge), and the thickened top layer or solid phase (SP, 30% volume in manure and 35% in sludge) were digested separately. Operating at 37 °C, the time needed to digest the LP from manure was shorter (10 days) than that needed to digest the corresponding SP or the untreated substrate (22 days in both cases). The time needed to digest the separated phases of sludge (LP: 2 days, SP: 15 days) was lower than that needed to digest manure. Biogas production rates for the manure after pretreatment were 0.5 L/L·day for the SP and 0.7 L/L·day for the LP, allowing higher OLR (4.5-4.8 gCOD/L·day) than when digesting untreated manure and increasing biogas production by 17%. IPF applied to sewage sludge led to a production of 1.8 L/L·day at an OLR of 6.2 gCOD/L·day for the SP and 2.0 L/L·day at 12.9 gCOD/L·day for the LP. Assuming a conventional OLR of 2-3 gCOD/L·day, the advantage of applying IPF to sewage sludge resides in the possibility of operating digesters at much higher OLR.

Source apportionment analysis was used to identify the factors contributing to atmospheric pollution at a monitoring location in the Southeast of Spain, a well documented area with an arid climate and high insolation favouring two sources of particulate matter: secondary transformation in the atmosphere and resuspension of crustal dry soils to the air. These conditions are further complicated by numerous industrial facilities in the area of the historical city of Cartagena. This paper describes the air quality of an area which includes a zinc metallurgical industry, a petrochemical factory, an oil power station, a shipyard and natural phenomena including African dust transport and resuspension of regional and/or local crustal materials. Major and trace element concentrations in PM10 and PM2.5 were determined at two monitoring stations in Cartagena (one PM10 sampler located at a traffic hotspot and the PM2.5 sampler at a suburban station), during 2004 and 2005. Results showed that in the PM10 fraction, the zinc metallurgical activity was linked to high levels of Cd, Zn and Pb; shipyard emission was associated with high levels of Cr and Ni; and high Ni and V levels were associated with the secondary aerosol indicating the contribution from oil combustion (oil-fired power station or petrochemical facilities). In the PM2.5 size fraction, the zinc source is defined by Zn and Pb; V, Ni and As appear with the oil combustion emissions. In contrast to PM10, shipyard activity is not consistently defined. Consistent sources found in both size fractions include crustal materials and traffic emissions.

Despite their significant role in source apportionment analysis, studies dedicated to the identification of tracer elements of emission sources of atmospheric particulate matter based on air quality data are relatively scarce. The studies describing tracer elements of specific sources currently available in the literature mostly focus on emissions from traffic or large-scale combustion processes (e.g. power plants), but not on specific industrial processes. Furthermore, marker elements are not usually determined at receptor sites, but during emission. In our study, trace element concentrations in PM10 and PM2.5 were determined at 33 monitoring stations in Spain throughout the period 1995–2006. Industrial emissions from different forms of metallurgy (steel, stainless steel, copper, zinc), ceramic and petrochemical industries were evaluated. Results obtained at sites with no significant industrial development allowed us to define usual concentration ranges for a number of trace elements in rural and urban background environments. At industrial and traffic hotspots, average trace metal concentrations were highest, exceeding rural background levels by even one order of magnitude in the cases of Cr, Mn, Cu, Zn, As, Sn, W, V, Ni, Cs and Pb. Steel production emissions were linked to high levels of Cr, Mn, Ni, Zn, Mo, Cd, Se and Sn (and probably Pb). Copper metallurgy areas showed high levels of As, Bi, Ga and Cu. Zinc metallurgy was characterised by high levels of Zn and Cd. Glazed ceramic production areas were linked to high levels of Zn, As, Se, Zr, Cs, Tl, Li, Co and Pb. High levels of Ni and V (in association) were tracers of petrochemical plants and/or fuel-oil combustion. At one site under the influence of heavy vessel traffic these elements could be considered tracers (although not exclusively) of shipping emissions. Levels of Zn–Ba and Cu–Sb were relatively high in urban areas when compared with industrialised regions due to tyre and brake abrasion, respectively.

Project AEMEP (Ref. No. 200800050084725), This paper presents a study of the effect of applying ultrasound pre-treatment in the production of methane when co-digesting mixtures of cattle manure with food waste and sludge. A series of experiments were carried out under mesophilic and thermophilic conditions in continuously stirred-tank reactors containing 70% cattle manure, 20% food waste and 10% sewage sludge. Ultrasound pre-treatment allows operating at lower HRT, achieving higher volumetric methane yields: 0.85 L CH4/L day at 36 C and 0.82 CH4/L day at 55 C, when cattle manure and sewage sludge were sonicated. With respect to the non-sonicated waste, these values represent increases of up to 31% and 67% for mesophilic and thermophilic digestion, respectively, Spanish Ministry for the Environment, Rural and Maritime Affairs

Biochemical methane potential (BMP) tests have been carried out on sewage sludge from two wastewater treatment plants to assess the effect of additives (FeCl 3 and two cationic polyelectrolytes) used in sludge dewatering. BMP tests were also carried out on the concentrated solid phase from the enzymic hydrolysis pre-treatment (42 °C, 48 h). FeCl 3 had no significant effect on specific methane production, obtaining 242–246 LCH 4 /kgVS o . The effect of the combination of polyelectrolyte and FeCl 3 depended on the polyelectrolyte and the sludge, but generally led to an increase in specific methane production (25–40%). When enzymic hydrolysis was applied as a pre-treatment, specific methane production increased from 6.8% in the sludge containing FeCl 3 to 20% in the sludge without FeCl 3 , although the increases were not statistically significant. In terms of LCH 4 /kgVS rem , a general improvement was achieved both by means of additives and by enzymic hydrolysis. However, this improvement was only significant in the case of sludge which had undergone previous enzymic hydrolysis (62%) and in the untreated sludge containing a polyelectrolyte and FeCl 3 (24%). Cationic polyelectrolytes inhibited solid–liquid separation during enzymic hydrolysis and, although the presence of only FeCl 3 did not affect this separation, a significant decrease (32%) in LCH 4 /kgVS rem was observed.

Average ranges of particulate matter (PM10 and PM2.5) concentrations and chemical composition in Spain show significant variations across the country, with current PM10 levels at several industrial and traffic hotspots exceeding recommended pollution limits. Such variations and exceedances are linked to patterns of anthropogenic and natural PM emissions, climate, and reactivity/stability of particulate species. PM10 and PM2.5 concentrations reach 14–22 μg PM10 m−3 and 8–12 μg PM2.5 m−3 at most rural/regional background sites, 25–30 μg PM10 m−3 and 15–20μg PM2.5 m−3 at suburban sites, 30–46 μg PM10 m−3 and 20–30 μg PM2.5 m−3 at urban background and industrial sites, and 46–50 μg PM10 m−3 and 30–35 μg PM2.5 m−3 at heavy traffic hotpots. Spatial distributions show sulphate and carbon particle levels reach maxima in industrialised areas and large cities (where traffic emissions are higher), and nitrate levels increase from the Atlantic to the Mediterranean (independent of the regional NOx emissions). African dust outbreaks have an influence on the number of exceedances of the daily limit value, but its additional load on the mean annual PM10 levels is only highly significant in Southern Iberia and Canary and Balearic islands. The marine aerosol contribution is near one order of magnitude higher in the Canaries compared to the other regions. Important temporal influences include PM intrusion events from Africa (more abundant in February–March and spring–summer), regional-scale pollution episodes, and weekday versus weekend activity. Higher summer insolation enhances (NH4)2SO4 but depletes particulate NO3− (as a consequence of the thermal instability of ammonium nitrate in summer) and Cl− (due to HCl volatilisation resulting from the interaction of gaseous HNO3 with the marine NaCl), as well as generally increasing dry dust resuspension under a semi-arid climate. Average trace metal concentrations rise with the highest levels at industrial and traffic hotspots sites, in some cases (Ti, Cr, Mn, Cu, Zn, As, Sn, W, and Pb) exceeding rural background levels by over an order of magnitude.

Ultrasound treatment is often applied to enhance the anaerobic digestion of sludge. Optimal conditions for organic matter solubilisation of primary, secondary and mixed sludge were assessed by implementing ultrasound disruption at different specific energies (from 3,500 to 21,000 kJ/kgTS). The variation in soluble chemical oxygen demand (sCOD) and ammonium nitrogen (NH4+-N) was monitored following the treatment, and after a subsequent fermentation (24 h, 37 °C). The effect of the treatment was clearly more pronounced in secondary sludge than in the other types of sludge. Relatively minimal values in solubility were found when applying ultrasound at different energies depending on the sludge (3,500-7,000 kJ/kgTS in primary sludge and 10,500-14,000 kJ/kgTS in secondary sludge). This minimal value was not so noticeable in mixed sludge. The addition of inoculum was not required after ultrasound disruption in order to perform the subsequent fermentation. After this final stage, no general pattern in terms of sCOD was observed. Increases and decreases were conditioned by the coverage of the ultrasound irradiation; NH4+-N values increased notably during the fermentation.

PM10 and black smoke were monitored at a suburban sampling station located in the northern Spanish city of Gijón. Thirty-two metals and total carbon (TC) (i.e., organic carbon (OC) and elemental carbon (EC)) were analyzed over a year. The study of air-mass origin based on 5-day back trajectories was carried out to assess its influence on the recovery data. Different strategies were implemented to infer the influence of traffic in the area. On average, TC accounted for 29 % of the PM10 fraction, with OC forming 77 % of this TC. The influence of traffic was clearly reduced during intense Atlantic advection episodes, when OC and EC decreased up to 0.39 and 0.22 μg C/m3, respectively. In contrast, the highest values were reported during regional episodes, exceeding 10 μg C/m3 of OC and 2 μg C/m3 of EC. The correlation between EC and OC was found to notably improve when considering the days with high traffic flow (from R2 = 0.46 to R2 = 0.74). This pattern was also reproduced by black smoke and EC (from R2 = 0.49 to R2 = 0.59). Cu and Sn were found to be reliable traffic tracers given their high dependence on EC (R2 = 0.82 and R2 = 0.79, respectively). Nevertheless, Sn, Ba, and Sb showed a better correlation with Cu than EC, suggesting a common origin. In the case of Sn, R2 improved from 0.79 to 0.91. The Cu/Sb ratio had a mean value of 6.6 which agrees with diagnostic criterions for brake wear particles. The relationships and ratios between EC, Cu, Sb, Sn, Ba, and Bi pointed out to non-exhaust emissions, playing a significant role in the chemical composition of PM10. Brake wear was presented as the most likely origin for Cu, Sb, and Sn. Electronic supplementary material The online version of this article (doi:10.1007/s11356-015-5955-8) contains supplementary material, which is available to authorized users.