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A comprehensive characterisation of atmospheric aerosols in the subtropical eastern North Atlantic has been carried out using long-term ground-based Aerosol Robotic NETwork (AERONET) photometric observations over the period 2005–2020 from a unique network made up of four stations strategically located from sea level to 3555 m on the island of Tenerife. This site can be considered a sentinel for the passage of airmasses going to Europe from Africa, and therefore the aerosol characterisation performed here adds important information for analysing their evolution during their path toward Northern Europe. Two of these stations (Santa Cruz de Tenerife – SCO – at sea level and La Laguna – LLO – at 580 m a.s.l.) are located within the marine atmospheric boundary layer (MABL), and the other two (Izaña – IZO – at 2373 m a.s.l. and Teide Peak – TPO – at 3555 m a.s.l.) are high mountain stations within the free troposphere (FT). Monthly climatology of the aerosol optical depth (AOD), Ångström exponent (AE), aerosol concentration, size distribution and aerosol optical properties has been obtained for the MABL and FT. Measurements that are quite consistent across the four sites have been used to categorise the main atmospheric scenarios, and these measurements confirm an alternation between predominant background conditions and predominant dust-loaded Saharan air mass conditions caused by seasonal dust transport over the subtropical North Atlantic. Background conditions prevail in the MABL and FT for most of the year, while dust-laden conditions dominate in July and August. The MABL under background conditions appears as a well-mixed layer with a low aerosol concentration (the volume concentration, VolCon, ranges from 0.02 ± 0.01 to 0.04 ± 0.02 µm3 µm−2), a predominance of coarse-mode marine aerosols (the effective radius, Reff, changes from 1.60 ± 0.19 to 1.91 ± 0.34 µm), and a volume contribution of the fine-mode fraction Vf/Vt . The clean FT is characterised by remarkably low aerosol loading and a predominant impact of fine-mode aerosols throughout the year (Vf/Vt has a maximum value of 0.93 ± 0.13), with an average Reff of 0.16 ± 0.02 µm. However, under dust-laden conditions and mainly in summer, we observe a predominance of coarse-mode aerosols with maximum VolCon values of 0.26 ± 0.23 µm3 µm−2 for the MABL and 0.16 ± 0.12 (0.06 ± 0.05) µm3 µm−2 for IZO (TPO), and a similar and quite consistent fine-mode fraction of 0.12 ± 0.03 in the vertical within the MABL and FT. Similarities in micro-physical and optical intensive aerosol properties confirm that the Saharan Air Layer (SAL) is a well-mixed layer in terms of the particulate composition. An estimation of the difference in the aerosol loading in the 1 km layer between IZO and TPO (in terms of VolCon and AOD) is performed in this study, and this shows that aerosol loading at IZO is double that at TPO, but they have similar fine-mode fractions, effective radii and intensive optical properties. The long-term trend analysis at SCO shows a significant negative trend in the fine-mode AOD between 2005 and 2020 (−1.8 ± 0.5) × 10−5 yr−1, which might be linked to the large reduction in oil-refining SO2 emissions from the SCO refinery in 2012.

By injecting aerosols and gases into the atmosphere, volcanoes significantly affect global climate, force changes in atmospheric dynamics, and influence many distinct cycles such as hydrological, carbon, and biogeochemical cycles. However, the irregular temporal and spatial distributions of volcanic processes and their effects are still poorly characterised. The volcanic eruption on La Palma (Canary Islands, Spain), which occurred in the autumn of 2021, presented an outstanding opportunity to improve the current understanding of these natural phenomena. The special conditions at the Izaña Observatory (IZO, Tenerife) and its proximity to La Palma (∼140 km) make it a strategic site for the comprehensive study of the almost unperturbed volcanic plume including the climate effects.In this context, the present work deals with the experimental estimation of the solar spectral direct radiative forcing (ΔF) and efficiency (ΔFEff) during the volcanic eruption based on radiation measurements performed with an EKO MS-711 grating spectroradiometer during three events characterised by the presence of different types of aerosols: fresh volcanic aerosols, Saharan mineral dust, and a mixture of volcanic and Saharan dust aerosols. Three case studies were identified using ground-based (lidar) data, satellite-based (Sentinel-5P Tropospheric Monitoring Instrument, TROPOMI) data, reanalysis data (Modern-Era Retrospective Analysis for Research and Applications, version 2, MERRA-2), and backward trajectories (Flexible Trajectories, FLEXTRA), and subsequently characterised in terms of optical and micro-physical properties using ground-based sun-photometry measurements. Despite the ΔF of the volcanic aerosols being greater than that of the dust events (associated with the larger aerosol load present), the ΔFEff was found to be lower. The spectral ΔFEff values at 440 nm ranged between −1.9 and −2.6 Wm−2nm−1AOD−1 for the mineral dust and mixed volcanic and dust particles, and between −1.6 and −3.3 Wm−2nm−1AOD−1 for the volcanic aerosols, considering solar zenith angles between 30∘ and 70∘, respectively.

The La Palma 2021 volcanic eruption was the first subaerial eruption in a 50-year period in the Canary Islands (Spain), emitting ~1.8 Tg of sulphur dioxide (SO2) into the troposphere over nearly 3 months (19 September-13 December 2021), exceeding the total anthropogenic SO2 emitted from the 27 European Union countries in 2019. We conducted a comprehensive evaluation of the impact of the 2021 volcanic eruption on air quality (SO2, PM10 and PM2.5 concentrations) utilising a multidisciplinary approach, combining ground and satellite-based measurements with height-resolved aerosol and meteorological information. High concentrations of SO2, PM10 and PM2.5 were observed in La Palma (hourly mean SO2 up to ~2600 μg m−3 and also sporadically at ~140 km distance on the island of Tenerife (> 7700 μg m−3) in the free troposphere. PM10 and PM2.5 daily mean concentrations in La Palma peaked at ~380 and 60 μg m−3. Volcanic aerosols and desert dust both impacted the lower troposphere in a similar height range (~ 0–6 km) during the eruption, providing a unique opportunity to study the combined effect of both natural phenomena. The impact of the 2021 volcanic eruption on SO2 and PM concentrations was strongly influenced by the magnitude of the volcanic emissions, the injection height, the vertical stratification of the atmosphere and its seasonal dynamics. Mean daily SO2 concentrations increased during the eruption, from 38 μg m−3 (Phase I) to 92 μg m−3 (Phase II), showing an opposite temporal trend to mean daily SO2 emissions, which decreased from 34 kt (Phase I) to 7 kt (Phase II). The results of this study are relevant for emergency preparedness in all international areas at risk of volcanic eruptions; a multidisciplinary approach is key to understand the processes by which volcanic eruptions affect air quality and to mitigate and minimise impacts on the population., The authors gratefully acknowledge the extraordinary effort carried out by the AEMET staff (both in La Palma and in support of the activities in La Palma) during the volcanic eruption, from the Izaña Atmospheric Research Center and the Delegation of AEMET in the Canary Islands. We thank the CSIC deployment service during the eruption and its coordination by Manuel Nogales. We also gratefully acknowledge the dedication and information provided by the PEVOLCA Scientific Committee and all the support received from the insular and local governments (Cabildo Insular de La Palma and the Ayuntamientos de Tazacorte, Los Llanos de Aridane and El Paso). The authors would also like to thank the Canary Islands Government for data from their Air Quality Monitoring Network and the MPL Network (MPLNET) for their support to the lidar measurements used in this paper. The authors also acknowledge the support from ACTRIS and ACTRIS-Spain, the Spanish Ministry of Science and Innovation and the support from the European Union H2020 program through the following projects (PID2019-104205GB-C21/AEI/10.13039/501100011033, EQC2018-004686-P, PID2019-103886RB-I00/AEI/10.13039/501100011033 and PID2020- 521-118793GA-I00) and programs (GA No. 654109, 778349, 871115, 101008004 and 101086690). Research activities of the CSIC staff during the eruption were funded by CSIC through the CSIC-PIE project with ID numbers PIE20223PAL009 and PIE20223PAL013 (Real Decreto 1078/2021, de 7 de diciembre). Part of this study was performed within the framework of the project AERO-EXTREME (PID2021-125669NBI00) funded by the Spanish State Research Agency (AEI) and ERDF funds.

Numerical weather prediction systems depend on Hyperspectral Infrared Sounder (HIS) data, yet the impacts of dust-contaminated HIS radiances on weather forecasts has not been quantified. To determine the impact of dust aerosol on HIS radiance assimilation, we use a modified radiance assimilation system employing a one-dimensional variational assimilation system (1DVAR) developed under the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) Numerical Weather Prediction–Satellite Application Facility (NWP-SAF) project, which uses the Radiative Transfer for TOVS (RTTOV). Dust aerosol impacts on analyzed temperature and moisture fields are quantified using synthetic HIS observations from rawinsonde, Micropulse Lidar Network (MPLNET), and Aerosol Robotic Network (AERONET). Specifically, a unit dust aerosol optical depth (AOD) contamination at 550 nm can introduce larger than 2.4 and 8.6 K peak biases in analyzed temperature and dewpoint, respectively, over our test domain. We hypothesize that aerosol observations, or even possibly forecasts from aerosol predication models, may be used operationally to mitigate dust induced temperature and moisture analysis biases through forward radiative transfer modeling.

A comprehensive characterization of atmospheric aerosols in the Subtropical Eastern North Atlantic has been carried out using long-term ground-based Aerosol Robotic NETwork (AERONET) photometric observations from a unique network made up of four stations strategically located from the sea level to 3555 m height on the island of Tenerife over the period 2005–2020. This site is can be considered a sentinel of the passage of airmass going to Europe from Africa and therefore the aerosol characterization performed here adds important information to analyse their evolution during the path toward Northern Europe. Two of these stations (Santa Cruz de Tenerife –SCO- at sea level and La Laguna –LLO- at 580 m asl) are located within the Marine Boundary Layer 5 (MBL) and the other two (Izana –IZO- at 2373 m asl and Teide Peak –TPO- at 3555 m asl) are high mountain stations within the Free Troposphere (FT). Monthly climatology of Aerosol Optical Depth (AOD), Angstrom Exponent (AE), aerosol concentration, size distribution, and aerosol optical properties has been obtained for the MBL and FT. Quite consistent measurements at the four sites have been used to categorise the main atmospheric scenarios confirming the predominance of the alternating background to dust-loaded Saharan air mass conditions seasonally affecting the sites as a result of the seasonal dust transport over the Subtropical North Atlantic. Background conditions prevail in the MBL and FT most of the year while dust-laden conditions dominate in July and August. The MBL under background conditions appears as a well-mixed layer with low aerosol concentration (volume concentration, VolCon, ranging from 0.02±0.01 to 0.04±0.02 μm3 · μm−2) with a predominance of coarse mode marine aerosols (effective radius, Re ff, changing from 1.60±0.19 to 1.91±0.34 μm) and fine mode fraction < 0.35. The clean FT has been characterised by remarkably low aerosol loading and a predominant impact of fine mode aerosols throughout the year (V f / V t with a maximum value of 0.93±0.13) with an average Re ff of 0.16±0.02 μm. However, under dust-laden conditions, we observe the predominance of coarse mode aerosols, mainly in summer, with maximum VolCon values of 0.26±0.23 μm3 · μm−2 for MBL and 0.16±0.12 (0.06±0.05) μm3 · μm−2 for IZO (TPO) and a similar and quite consistent fine mode fraction of 0.120.03 in the vertical within MBL and FT. Similarities in micro-physical and optical intensive aerosol properties confirm the Saharan Air Layer (SAL) as a well-mixed layer in terms of the particulate composition. An estimation of the difference in the aerosol loading in the 1-km layer between IZO and TPO (in terms of VolCon and AOD) is performed in this study, showing that aerosol loading at IZO is double that of TPO but with similar fine mode fraction, effective radius and optical intensive properties. The long-term trend analysis at SCO shows a negative significant trend in the fine AOD mode between 2005 and 2020 (-1.8±0.5) ·10−5 yr−1, which might be linked to the large reduction of oil refining SO2 emissions at SCO refinery in 2012.

The management of natural hazards is a vital concern for the sustainable development of any country and information is the single most important factor to tackle the risks from natural hazards within the risk reduction phase, and to manage response during a crisis. To cope with these challenges it is required, on one hand, to collect baseline information on the natural systems to understand their current state, to identify changes and predict or forecast their future behaviour and, on the other hand, to update information during crisis to review and determine management strategies.One major difficulty to this approach is the economic weight of the classic monitoring systems, requiring heavy investments, costly maintenance, and substantial human resources. To overcome these obstacles, an alternative concept was developed based on low-cost and fast deployable wireless sensors networks made by autonomous devices, each capable to communicate to a cloud computing service that compiles and processes data, producing information readily accessible via web.The 2021 eruption of the Cumbre Vieja volcano presented an excellent opportunity for a proof of concept of this idea. A trial run was set up on this challenging environment, focusing mainly on the detection and measurement of eruptive products, targeting the measurement of eruptive plume components, such as carbon dioxide (CO2), sulphur dioxide (SO2) and ash (particle matter, PM), and the monitoring of lava flows entering the sea. Besides the sensor’s setups, also the automatic data processing and different communications were tested.The experiment consisted of a proximal network of different stations measuring CO2, SO2, PM10, PM2.5, temperature, and humidity; a set of trials to intercept the eruptive plume with weather balloons to measure in-situ the same parameters; a distal aethalometer to detect particles from the distal plume; and a set of buoys to monitor hydroacoustic and environmental parameters in the proximity of the lava deltas. The proximal network allowed for a continuous monitoring with information immediately available via web, with good spatial and temporal correlations between different parameters. The atmospheric soundings allowed to measure particle mass concentrations and sulphur dioxide along a profile of the eruptive plume and characterize its vertical profile, with in situ measurements, while back trajectory of air parcel analyses and aethalometer measurements carried out at Izaña Atmospheric Observatory (2367 m.a.s.l.) showed attenuation variability that could be associated with small volcanic particles transported to at least 140 km from the source. The buoys trial allowed to record the acoustic environment near the lava deltas and to test the design and configurations of the device regarding sensors integration and communications.The Cumbre Vieja eruption experiment allowed to try-out a fast deployment low-cost multi-sensor system with good results on volcanic plume characterization and real-time data production that proved to be useful for managing volcanic crisis and demonstrated the relevance of this alternative monitoring concept.

El propósito de esta guía es presentar las bases para el establecimiento de protocolos de control y prevención, para mitigar el impacto en la salud de la exposición a la contaminación del aire de origen volcánico, y su aplicación en el Observatorio Atmosférico de Izaña (OAI). La guía se ha desarrollado a partir del protocolo que se elaboró de urgencia en el OAI para dar una respuesta rápida a los posibles problemas asociados a los efectos de la erupción del volcán de La Palma en Septiembre de 2021 sobre el Observatorio, aportando una explicación motivada a los umbrales y acciones descritas en la misma, ya que no existía material en castellano que aglutinara dicha información. Para ello se han consultado guías internacionales publicadas principalmente por departamentos de salud de zonas habitualmente expuestas a este tipo de contaminación (Hawaii, Islandia, etc.), así como información de la “International Volcanic Health Hazard Network (IVHHN)” (Red Internacional de Riesgos Volcánicos para la Salud).

In the brain, canonical excitatory neurotransmission is mediated by L-glutamate and its ionotropic (iGluR) and metabotropic (mGluR) receptors. The wide diversity of these often limits the development of glutamatergic drugs. This is due to the arduousness of achieving selectivity with specific ligands. In the present article, encouraged by reports of bioactive organoboron compounds, a diphenylboroxazolidone derived from quinolinate (BZQuin) was evaluated. BZQuin was synthesized with a yield of 87%. Its LD50 was 174 mg/kg in male CD-1 mice, as estimated by a modified Lorke’s method. BZQuin exerted a reduced ability to cause seizures when compared against its precursor, quinolinate. The latter suggested that it does not directly stimulate the ionotropic NMDA receptors or other ionic channels. The observation that the antiglutamatergic drugs riluzole and memantine displaced the BZQuin effect left the mGluRs as their possible targets. This is in line with results from molecular-docking simulations. During these simulations, BZQuin bound only to orthosteric sites on mGluR1, mGluR2, and mGluR7, with higher affinity than quinolinate. The survival of the neurons of mice previously administered with BZQuin or quinolinate was quantified in four neuroanatomical structures of the brain. The BZQuin effect was more appreciable in brain regions with a high expression of the previously mentioned mGluRs, while both antiglutamatergic drugs exerted a neuroprotective effect against it. Together, these results suggest that BZQuin exerts a positive influence on glutamatergic neurotransmission while selectively interacting with certain mGluRs.

Boron-containing compounds (BCC) exert effects on neurons. After the expanding of both the identification and synthesis of new BCC, novel effects in living systems have been reported, many of these involving neuronal action. In this review, the actions of BCC on neurons are described; the effects have been inferred by boron deprivation or addition. Also, the effects can be related to those mediated by interaction on ionic channels, G-protein coupled receptors, or other receptors exerting modification on neuronal behavior. Additionally, BCC have exhibited effects by the modulation of inflammation or oxidative processes. BCC are expanding as drugs. Deprivation of boron sources from the diet shows the role of some natural BCC. However, the observations of several new synthesized compounds suggest their ability to act with attractive potency, efficacy, and long-term action on neuronal receptors or processes related with the origin and evolution of neurodegenerative processes. The details of BCC-target interactions are currently being elucidated in progress, as those observed from BCC-protein crystal complexes. Taking all of the above into account, the expansion is presumably near to having studies on the application of BCC as drugs on specific targets for treating neurodegenerative diseases.

One of the challenges in studying desert dust aerosol along with its numerous interactions and impacts is the paucity of direct in-situ measurements, particularly in the areas most affected by dust storms. Satellites typically provide columnintegrated aerosol measurements, but observationally-constrained continuous 3D dust fields are needed to assess dust variability, climate effects and impacts upon a variety of socio-economic sectors. Here, we present a high resolution regional reanalysis data set of desert dust aerosols that covers Northern Africa, the Middle East and Europe along with the Mediterranean sea and parts of Central Asia, and the Atlantic and Indian Oceans between 2007 and 2016. The horizontal resolution is 0.1° latitude × 0.1° longitude, and the temporal resolution is 3 hours. The reanalysis was produced using Local Ensemble Transform Kalman Filter (LETKF) data assimilation in the Multiscale Online Non-hydrostatic AtmospheRe CHemistry model (MONARCH) developed at the Barcelona Supercomputing Center (BSC). The assimilated data are coarse-mode dust optical depth retrieved from the Moderate Resolution Imaging Spectroradiometer (MODIS) Deep Blue Level 2 products. The reanalysis data set consists of upper air (dust mass concentrations and extinction coefficient), surface (dust deposition and solar irradiance fields, among them) and total column (e.g., dust optical depth and load) variables. Some dust variables, such as concentrations and wet and dry deposition, are expressed for a binned size distribution that ranges from 0.2 to 20 μm in particle diameter. Both analysis and first-guess (analysis-initialized simulation) fields are available for the variables that are diagnosed from the state vector. A set of ensemble statistics is archived for each output variable, namely the ensemble mean, standard deviation, maximum and median. The spatial and temporal distribution of the dust fields follows well-known dust cycle features controlled by seasonal changes in meteorology and vegetation cover. The analysis is statistically closer to the assimilated retrievals than the first-guess, which proves the consistency of the data assimilation method. Independent evaluation using AERONET dust-filtered optical depth retrievals indicates that the reanalysis data set is highly accurate (mean bias = −0.05, RMSE = 0.12, r = 0.81 when compared to retrievals from the spectral de-convolution algorithm on a 3-hourly basis). Verification statistics are broadly homogeneous in space and time with regional differences that can be partly attributed to model limitations (e.g., poor representation of small-scale emission processes), presence of aerosols other than dust in the observations used in the evaluation, and differences in the number of observations among seasons. Such a reliable high-resolution historical record of atmospheric desert dust will allow a better quantification of dust impacts upon key sectors of society and economy, including health, solar energy production and transportation. The reanalysis data set (Di Tomaso et al., 2021) is distributed via a Thematic Real-time Environmental Distributed Data Service (THREDDS) at BSC and freely available at http://hdl.handle.net/21.12146/c6d4a608-5de3-47f6-a004-67cb1d498d98.

At the end of 2015, a CO2/CH4/CO cavity ring-down spectrometer (CRDS) was installed at the Izaña Global Atmosphere Watch (GAW) station (Tenerife, Spain) to improve the Izaña Greenhouse Gases GAW Measurement Programme, and to guarantee the renewal of the instrumentation and the long-term maintenance of this program. We present the results of the CRDS acceptance tests, the raw data processing scheme applied, and the response functions used. Also, the calibration results, the implemented water vapor correction, the target gas injection statistics, the ambient measurements performed from December 2015 to July 2017, and their comparison with other continuous in situ measurements are described. The agreement with other in situ continuous measurements is good most of the time for CO2 and CH4, but for CO it is just outside the GAW 2 ppb objective. It seems the disagreement is not produced by significant drifts in the CRDS CO World Meteorological Organization (WMO) tertiary standards. The more relevant contributions of the present article are (1) determination of linear relationships between flow rate, CRDS inlet pressure, and CRDS outlet valve aperture; (2) determination of a slight CO2 correction that takes into account changes in the inlet pressure/flow rate (as well as its stability over the years), and attributing it to the existence of a small spatial inhomogeneity in the pressure field inside the CRDS cavity due to the gas dynamics; (3) drift rate determination for the pressure and temperature sensors located inside the CRDS cavity from the CO2 and CH4 response function drift trends; (4) the determination of the H2O correction for CO has been performed using raw spectral peak data instead of the raw CO provided by the CRDS and using a running mean to smooth random noise in a long water-droplet test (12 h) before performing the least square fit; and (5) the existence of a small H2O dependence in the CRDS flow and of a small spatial inhomogeneity in the temperature field inside the CRDS cavity are pointed out and their origin discussed.

The objective is to derive methane (CH4) emissions of the metropolitan city Madrid Spain from the CH4 enhancements seen by the space-borne and the ground-based instruments. This study applies satellite-based measurements from the TROPOspheric Monitoring Instrument (TROPOMI) and the Infrared Atmospheric Sounding Interferometer (IASI) together with measurements from the ground-based COllaborative Carbon Column Observing Network (COCCON) instruments. In 2018, a two-week field campaign for measuring the atmospheric concentrations of greenhouse gases was performed in Madrid in the framework of Monitoring greenhousE Gas EmIssions of Madrid city (MEGEI-MAD) project. Five COCCON instruments were deployed at different locations around the Madrid city center enabling the observation of total column averaged CH4 mixing ratios (XCH4). Using available wind data, the differences between CH4 columns observed at these locations allow to estimate the emissions emerging from the surrounded area. In addition, based on the dominating wind direction in the Madrid region, we calculate the difference of the satellite data maps for two opposite wind regimes (northeast – southwest, NE – SW). In the following, we refer to the resultant signal as the wind-assigned anomaly. We use TROPOMI tropospheric nitrogen dioxide (NO2) observations as a test to verify our method of wind-assigned anomaly and its implementation, taking advantage of the much better detectability of the plume due to the short lifetime and low background concentrations of NO2. Pronounced bipolar plumes are found along NE and SW wind direction, which implies that our method of wind-assigned anomaly is working as expected. The wind-assigned TROPOMI XCH4 anomaly shows much weaker symmetric plumes than NO2 due to the long lifetime of CH4 and in consequence a high accumulated background of CH4 in the atmosphere. The wind-assigned plume method is also applied to the tropospheric and upper tropospheric/stratospheric column averaged CH4 mixing ratio products (in the following referred to as TXCH4 and UTSXCH4) derived from a-posteriori merged Infrared Atmospheric Sounding Interferometer (IASI) profile and TROPOMI total column data. Based on the NE and SW wind fields, we developed a simple plume model locating the source at three waste disposal sites east of Madrid for CH4. As CH4 emission strength we estimate 7.4 × 1025 ± 6.4 × 1024 molec s−1 from the TROPOMI XCH4 data and 7.1 × 1025 ± 1.0 × 1025 molec s−1 from the TROPOMI&IASI merged TXCH4 data. The COCCON observations indicate a weaker CH4 emission strength of around 3.7 × 1025 molec s−1 from local source (near to the Valdemingómez waste plant) in accordance with observations in a single day and. All emission rates estimated from the different observations are significantly larger than the emission rates provided via the official Spanish Register of Emissions and Pollutant Sources.

Precipitable water vapor retrievals are of major importance for assessing and understanding atmospheric radiative balance and solar radiation resources. On that basis, this study presents the first PWV values measured with a novel EKO MS-711 grating spectroradiometer from direct normal irradiance in the spectral range between 930 and 960 nm at the Izaña Observatory (IZO, Spain) between April and December 2019. The expanded uncertainty of PWV (UPWV) was theoretically evaluated using the Monte-Carlo method, obtaining an averaged value of 0.37 ± 0.11 mm. The estimated uncertainty presents a clear dependence on PWV. For PWV ≤ 5 mm (62% of the data), the mean UPWV is 0.31 ± 0.07 mm, while for PWV > 5 mm (38% of the data) is 0.47 ± 0.08 mm. In addition, the EKO PWV retrievals were comprehensively compared against the PWV measurements from several reference techniques available at IZO, including meteorological radiosondes, Global Navigation Satellite System (GNSS), CIMEL-AERONET sun photometer and Fourier Transform Infrared spectrometry (FTIR). The EKO PWV values closely align with the above mentioned different techniques, providing a mean bias and standard deviation of −0.30 ± 0.89 mm, 0.02 ± 0.68 mm, −0.57 ± 0.68 mm, and 0.33 ± 0.59 mm, with respect to the RS92, GNSS, FTIR and CIMEL-AERONET, respectively. According to the theoretical analysis, MB decreases when comparing values for PWV > 5 mm, leading to a PWV MB between −0.45 mm (EKO vs. FTIR), and 0.11 mm (EKO vs. CIMEL-AERONET). These results confirm that the EKO MS-711 spectroradiometer is precise enough to provide reliable PWV data on a routine basis and, as a result, can complement existing ground-based PWV observations. The implementation of PWV measurements in a spectroradiometer increases the capabilities of these types of instruments to simultaneously obtain key parameters used in certain applications such as monitoring solar power plants performance. This study has been performed thanks to regular funds from the State Meteorological Agency of Spain (AEMET) to the World Meteorological Organization (WMO) Commission for Instruments and Methods of Observations (CIMO) Izaña Testbed for Aerosols and Water Vapor Remote Sensing Instruments and the European Community Research Infrastructure Action under the FP7 ACTRIS grant, agreement no. 262254.

High-resolution Fourier transform infrared (FTIR) solar observations are particularly relevant for climate studies, as they allow atmospheric gaseous composition and multiple climate processes to be monitored in detail. In this context, the present paper provides an overview of 20 years of FTIR measurements taken in the framework of the NDACC (Network for the Detection of Atmospheric Composition Change) from 1999 to 2018 at the subtropical Izaña Observatory (IZO, Spain). Firstly, long-term instrumental performance is comprehensively assessed, corroborating the temporal stability and reliable instrumental characterization of the two FTIR spectrometers installed at IZO since 1999. Then, the time series of all trace gases contributing to NDACC at IZO are presented (i.e. C2H6, CH4, ClONO2, CO, HCl, HCN, H2CO, HF, HNO3, N2O, NO2, NO, O3, carbonyl sulfide (OCS), and water vapour isotopologues H162O, H182O, and HD16O), reviewing the major accomplishments drawn from these observations. In order to examine the quality and long-term consistency of the IZO FTIR observations, a comparison of those NDACC products for which other high-quality measurement techniques are available at IZO has been performed (i.e. CH4, CO, H2O, NO2, N2O, and O3). This quality assessment was carried out on different timescales to examine what temporal signals are captured by the FTIR records, and to what extent. After 20 years of operation, the IZO NDACC FTIR observations have been found to be very consistent and reliable over time, demonstrating great potential for climate research. Long-term NDACC FTIR data sets, such as IZO, are indispensable tools for the investigation of atmospheric composition trends, multi-year phenomena, and complex climate feedback processes, as well as for the validation of past and present space-based missions and chemistry climate models. The Izaña FTIR station has been supported by the German Bundesministerium für Wirtschaft und Energie (BMWi) via DLRunder grants 50EE1711A and by the Helmholtz Society via the research program ATMO. In addition, this research was funded by the European Research Council under FP7/(2007-2013)/ERC Grant agreement nº 256961 (project MUSICA), by the Deutsche Forschungsgemeinschaft for the project MOTIV (GeschaFTIRzeichen SCHN 1126/2-1), by the Ministerio de Economía y Competitividad from Spain through the projects CGL2012-37505 (project NOVIA) and CGL2016-80688-P (project INMENSE), and by EUMETSAT under its Fellowship Programme (project VALIASI).

Every year, large-scale African dust outbreaks frequently pass over the Canary Islands (Spain). Here we describe the seasonal evolution of atmospheric aerosol extinction and meteorological vertical profiles at Tenerife over the period 2007–2018 using long-term Micropulse Lidar (MPL-3) and radiosondes observations. These measurements are used to categorise the different patterns of dust transport over the subtropical North Atlantic and, for the first time, to robustly describe the dust vertical distribution in the Saharan Air Layer (SAL) over this region. Three atmospheric scenarios dominate the aerosol climatology: dust-free (clean) conditions, the summer-Saharan scenario (Summer-SAL) and the winter-Saharan scenario (Winter-SAL). A relatively well-mixed marine boundary layer (MBL) was observed in the case of clean (dust-free) conditions; it was associated with lidar extinction coefficients (α) ∼ 0.030 km−1 with minimum α (−1) in the free troposphere (FT). The Summer-SAL has been characterised as a dust-laden layer strongly affecting both the MBL (∆α = 48 % relative to clean conditions) and the free troposphere. The Summer-SAL appears as a well-stratified layer, relatively dry at lower levels but more humid at higher levels compared with clean FT (CFT) conditions (∆r ∼ −44 % at the SAL’s base and ∆r ∼ +332 % at 5.3 km, where is the water vapour mixing ratio), with a peak of α > 0.066 km−1 at ∼ 2.5 km. Desert dust is present up to ∼ 6.0 km, the SAL top based on the altitude of SAL’s temperature inversion (STI). In the Winter-SAL scenario, the dust layer is confined to lower levels, below 2 km altitude. This layer is characterized by a dry anomaly at lower levels (∆r ∼ −38 % in comparison to the clean scenario) and a dust peak at ∼ 1.3 km height. CFT conditions were found above 2.3 km. Our results reveal the important role that both dust and water vapour play in the radiative balance within the Summer- and Winter-SAL. The dominant dust-induced shortwave (SW) radiative warming in summer (heating rates up to +0.7 K day−1) is found slightly below the dust maximum. However, the dominant contribution of water vapour was observed as a net SW warming observed within the SAL (from 2.1 km to 5.7 km) and as a strong cold anomaly near the SAL’s top (−0.6 K day−1). The conventional description of the Summer-SAL as a “dry layer” might lead to underestimating the importance of the atmospheric water vapour radiative effect. In the case of the Winter-SAL, we observed a dust-induced radiative effect dominated by SW heating (maximum heating of +0.7 K day−1 at 1.5 km, near the dust peak); both dust and atmospheric water vapour impact heating in the atmospheric column. This is the case of the SW heating within the SAL (maximum near the r peak), the dry anomaly at lower levels (∆r ∼ −38 % at 1 km) and the thermal cooling (∼ 0.3 K day−1) from the STI upwards. Finally, we hypothesise that the SAL can impact heterogeneous ice nucleation processes through the frequent occurrence of mid-level clouds observed near the SAL top at relatively warm temperatures. A dust event that affected Tenerife in August 2015 is simulated using the regional DREAM model to assess the role of dust and water vapour carried within SAL in the ice nucleation processes. The modelling results reproduce the arrival of the dust plume and its extension over the island and confirm the observed relationship between the Summer-SAL conditions and the formation of mid- and high-level clouds.

Extracting globally representative trend information from lower tropospheric ozone observations is extremely difficult due to the highly variable distribution and interannual variability of ozone, and the ongoing shift of ozone precursor emissions from high latitudes to low latitudes. Here we report surface ozone trends at 27 globally distributed remote locations (20 in the Northern Hemisphere, 7 in the Southern Hemisphere), focusing on continuous time series that extend from the present back to at least 1995. While these sites are only representative of less than 25% of the global surface area, this analysis provides a range of regional long-term ozone trends for the evaluation of global chemistry-climate models. Trends are based on monthly mean ozone anomalies, and all sites have at least 20 years of data, which improves the likelihood that a robust trend value is due to changes in ozone precursor emissions and/or forced climate change rather than naturally occurring climate variability. Since 1995, the Northern Hemisphere sites are nearly evenly split between positive and negative ozone trends, while 5 of 7 Southern Hemisphere sites have positive trends. Positive trends are in the range of 0.5–2 ppbv decade–1, with ozone increasing at Mauna Loa by roughly 50% since the late 1950s. Two high elevation Alpine sites, discussed by previous assessments, exhibit decreasing ozone trends in contrast to the positive trend observed by IAGOS commercial aircraft in the European lower free-troposphere. The Alpine sites frequently sample polluted European boundary layer air, especially in summer, and can only be representative of lower free tropospheric ozone if the data are carefully filtered to avoid boundary layer air. The highly variable ozone trends at these 27 surface sites are not necessarily indicative of free tropospheric trends, which have been overwhelmingly positive since the mid-1990s, as shown by recent studies of ozonesonde and aircraft observations. The IAGOS program acknowledges the European Commission for its support of the MOZAIC project (1994–2003) the preparatory phase of IAGOS (2005–2013) and IGAS (2013–2016).

Recent studies have found increases in the cardiovascular mortality rates during poor air quality events due to outbreaks of desert dust. In Tenerife, we collected (2014&ndash, 2017) data in 829 patients admitted with a heart failure diagnosis in the Emergency Department of the University Hospital of the Canaries. In this region, concentrations of PM10 and PM2.5 are usually low (~20 and 10 &micro, g/m3), but they increase to 360 and 115 &mu, g/m3, respectively, during Saharan dust events. By using statistical tools (including multivariable logistic regressions), we compared in-hospital mortality of patients with heart failure and exposure to PM10 and PM2.5 during dust and no-dust events. We found that 86% of in-hospital heart failure mortality cases occurred during Saharan dust episodes that resulted in PM10 &gt, 50 &micro, g/m3 (interquartile range: 71&ndash, 96 &micro, g/m3). A multivariate analysis showed that, after adjusting for other covariates, exposure to Saharan dust events associated with PM10 &gt, g/m3 was an independent predictor of heart failure in-hospital mortality (OR = 2.79, 95% CI (1.066&ndash, 7.332), p = 0.03). In conclusion, this study demonstrates that exposure to high Saharan dust concentrations is independently associated with in-hospital mortality in patients with heart failure.

Air pollution has many adverse effects on health and is associated with an increased risk of mortality. Desert dust outbreaks contribute directly to air pollution by increasing particulate matter concentrations. We investigated the influence of desert dust outbreaks on air quality in Santa Cruz de Tenerife, a city located in the dust export pathway off the west coast of North Africa, using air-quality observations from a six-year period (2012&ndash, 2017). During winter intense dust outbreaks PM 10 mean (24-h) concentrations increased from 14 &mu, g m - 3 to 98 &mu, g m - 3 , on average, and PM 2 . 5 mean (24-h) concentrations increased from 6 &mu, g m - 3 to 32 &mu, g m - 3 . Increases were less during summer outbreaks, with a tripling of PM 10 and PM 2 . 5 daily mean concentrations. We found that desert dust outbreaks reduced the height of the marine boundary layer in our study area by &gt, 45%, on average, in summer and by &sim, 25%, on average, in winter. This thinning of the marine boundary layer was associated with an increase of local anthropogenic pollution during dust outbreaks. NO 2 and NO mean concentrations more than doubled and even larger relative increases in black carbon were observed during the more intense summer dust outbreaks, increases also occurred during the winter outbreaks but were less than in summer. This has public health implications, local anthropogenic emissions need to be reduced even further in areas that are impacted by desert dust outbreaks to reduce adverse health effects.

Aerosol Optical Depth (AOD) and the Ångström Exponent (AE) have been calculated in the near infrared (NIR) and short-wave infrared (SWIR) spectral regions over a period of one year (May 2019–May 2020) at the high-mountain Izaña Observatory (IZO) from Fourier Transform Infrared (FTIR) solar spectra. The high-resolution FTIR measurements were carried out coincidentally with Cimel CE318-T photometric observations in the framework of the Aerosol Robotic Network (AERONET). A spectral FTIR AOD was generated using two different approaches: by means of the selection of seven narrow FTIR micro-windows (centred at 1020.90, 1238.25, 1558.25, 1636.00, 2133.40, 2192.00, and 2314.20 nm) with negligible atmospheric gaseous absorption, and by using the CE318-AERONET’s response function in the near-coincident bands (1020 nm and 1640 nm) to degrade the high-resolution FTIR spectra. The FTIR system was absolutely calibrated by means of a continuous Langley–Plot analysis over the 1-year period. An important temporal drift of the calibration constant was observed as a result of the environmental exposure of the FTIR’s external optical mirrors (linear degradation rate up to 1.75% month−1). The cross-validation of AERONET-FTIR databases documents an excellent agreement between both AOD products, with mean AOD differences below 0.004 and root-mean-squared errors below 0.006. A rather similar agreement was also found between AERONET and FTIR convolved bands, corroborating the suitability of low-resolution sunphotometers to retrieve high-quality AOD data in the NIR and SWIR domains. In addition, these results demonstrate that the methodology developed here is suitable to be applied to other FTIR spectrometers, such as portable and low-resolution FTIR instruments with a potentially higher spatial coverage. The spectral AOD dependence for the seven FTIR micro-windows have been also examined, observing a spectrally flat AOD behaviour for mineral dust particles (the typical atmospheric aerosols presented at IZO). A mean AE value of 0.53 ± 0.08 for pure mineral dust in the 1020–2314 nm spectral range was retrieved in this paper. A subsequent cross-validation with the MOPSMAP (Modeled optical properties of ensembles of aerosol particles) package has ensured the reliability of the FTIR dataset, with AE values between 0.36 to 0.60 for a typical mineral dust content at IZO of 100 cm−3 and water-soluble particle (WASO) content ranging from 600 to 6000 cm−3. The new database generated in this study is believed to be the first long-term time series (1-year) of aerosol properties generated consistently in the NIR and SWIR ranges from ground-based FTIR spectrometry. As a consequence, the results presented here provide a very promising tool for the validation and subsequent improvement of satellite aerosol products as well as enhance the sensitivity to large particles of the existing databases, required to improve the estimation of the aerosols’ radiative effect on climate. This study has been performed thanks to regular funds from the State Meteorological Agency of Spain (AEMET) to the World Meteorological Organization (WMO) Commission for Instruments and Methods of Observations (CIMO) Izaña Testbed for Aerosols and Water Vapor Remote Sensing Instruments, dedicated resources from SIELTEC S.L., and the European Community Research Infrastructure Action under the FP7 ACTRIS grant, agreement no. 262254. The authors also acknowledge the support from the Ministerio de Economía y Competitividad from Spain through the project INMENSE (CGL2016-80688-P) and Izaña staff for maintaining the instrumentation, thus ensuring the quality of the data.

It was previously shown that during August the export of Saharan dust to the Atlantic was strongly affected by the difference of the 700-hPa geopotential height anomaly between the subtropics and the tropics over North Africa, which was termed the North African Dipole Intensity (NAFDI). In this work a more comprehensive analysis of the NAFDI is performed, focusing on the entire summer dust season (June–September), and examining the interactions between the mid-latitude Rossby waves (MLRWs) and NAFDI. Widespread and notable aerosol optical depth (AOD) monthly anomalies are found for each NAFDI-phase over the dust corridors off the Sahara, indicating that NAFDI presents intra-seasonal variability and drives dust transport over both the Mediterranean basin and the North Atlantic. Those summer months with the same NAFDI-phase show similar AOD-anomaly patterns. Variations in NAFDI-phase also control the displacement of the Saharan Heat Low (SHL) westwards or eastwards through horizontal advection of temperature over Morocco-Western Sahara or eastern Algeria-Western Libya, respectively. The connection between the SHL and the NAFDI is quantified statistically by introducing two new daily indexes that account for their respective phases (NAFDI daily index -NAFDIDI-, and SHL longitudinal shift index -SHLLSI-) and explained physically using the energy equation of the atmospheric dynamics. The Pearson's correlation coefficient between the one–day-lag SHLLSI and the NAFDIDI for an extended summer season (1980–2013) is 0.78. A positive NAFDI is associated with the West-phase of the SHL, dust sources intensification on central Algeria, and positive AOD anomalies over this region and the Subtropical North Atlantic. A negative NAFDI is associated with the East-phase of the SHL, and positive AOD anomalies over central-eastern Sahara and the central-western Mediterranean Sea. The results point out that the phase changes of NAFDI at intra-seasonal time scale are conducted by those MLRWs that penetrate deeply into the low troposphere. This work is part of the research activities developed by the WMO SDS-WAS Regional Centre for Northern Africa, Middle East and Europe, held by AEMET and BSC-CNS. This study also contributes to Copernicus Atmosphere Monitoring Service (CAMS). Our acknowledgment to ECMWF for providing MACC-dust reanalysis. The authors wish to thank NCEP/NCAR Reanalysis Project. We acknowledge NASA LADS for providing MODIS data. The University of Granada (Spain) and its “Physics and Space Sciences” PhD Programme are acknowledged by A. J. Gómez-Peláez and E. Cuevas. AEROATLAN project (CGL2015-17 66229-P), co-funded by the Ministry of Economy and Competitiveness of Spain and the European Regional Development Fund contributed to this study. Sara Basart acknowledges the CICYT project (CGL2013-46736). 3.708 JCR (2017) Q1, 54/241 Environmental Sciences, 16/86 Meteorology and Atmospheric Sciences UEC

A new zenith-looking narrow-band radiometer based system (ZEN), conceived for dust aerosol optical depth (AOD) monitoring, is presented in this paper. The ZEN system comprises a new radiometer (ZEN-R41) and a methodology for AOD retrieval (ZEN-LUT). ZEN-R41 has been designed to be stand alone and without moving parts, making it a low-cost and robust instrument with low maintenance, appropriate for deployment in remote and unpopulated desert areas. The ZEN-LUT method is based on the comparison of the measured zenith sky radiance (ZSR) with a look-up table (LUT) of computed ZSRs. The LUT is generated with the LibRadtran radiative transfer code. The sensitivity study proved that the ZEN-LUT method is appropriate for inferring AOD from ZSR measurements with an AOD standard uncertainty up to 0.06 for AOD500 nm ∼ 0.5 and up to 0.15 for AOD500 nm ∼ 1.0, considering instrumental errors of 5 %. The validation of the ZEN-LUT technique was performed using data from AErosol RObotic NETwork (AERONET) Cimel Electronique 318 photometers (CE318). A comparison between AOD obtained by applying the ZEN-LUT method on ZSRs (inferred from CE318 diffuse-sky measurements) and AOD provided by AERONET (derived from CE318 direct-sun measurements) was carried out at three sites characterized by a regular presence of desert mineral dust aerosols: Izaña and Santa Cruz in the Canary Islands and Tamanrasset in Algeria. The results show a coefficient of determination (R2) ranging from 0.99 to 0.97, and root mean square errors (RMSE) ranging from 0.010 at Izaña to 0.032 at Tamanrasset. The comparison of ZSR values from ZEN-R41 and the CE318 showed absolute relative mean bias (RMB) R2 higher than 0.97.

Cirrus (Ci) cloud properties can change significantly from place to place over the globe as a result of weather processes, reflecting their likely different radiative and climate implications. In this work Cirrus clouds (Ci) features observed in late autumn/early winter season at both subtropical and polar latitudes are examined and compared to CALIPSO/CALIOP observations. Lidar measurements were carried out in three stations: Sao Paulo (MSP, Brazil) and Tenerife (SCO, Canary Islands, Spain), as subtropical sites, and the polar Belgrano II base (BEL, Argentina) in the Antarctic continent. The backscattering ratio (BSR) profiles and the top and base heights of the Ci layers together to their Cirrus Cloud Optical Depth (CCOD) and Lidar Ratio (LR) for Ci clouds were derived. In addition, temperatures at the top and base boundaries of the Ci clouds were also obtained from local radiosoundings to verify pure ice Ci clouds occurrence using a given temperature top threshold ( 70 km far), inferring the irregular extension and inhomogeneity of the Ci clouds over each study area. These considerations can be useful for assimilation of the Ci features into climate models and evaluation of future space-borne lidar observations of Ci clouds, especially for the future ESA/Copernicus-Sentinel and ESA/EarthCARE missions.

Spectral direct UV-Visible normal solar irradiance (DNI) measured with an EKO MS-711 spectroradiometer at the Izaña Atmospheric Observatory (IZO, Spain) has been used to determine aerosol optical depth (AOD) at several wavelengths (340, 380, 440, 500, 675 and 870 nm) between April and September 2019 that have been compared with synchronous AOD measurements from a reference Cimel-AERONET (Aerosol RObotic NETwork) sunphotometer. The EKO MS-711 has been calibrated at Izaña Observatory using the Langley-Plot method during the study period. Although this instrument has been designed for spectral solar DNI measurements, and therefore has a field of view (FOV) of 5° that is twice that recommended in solar photometry for AOD determination, the AOD differences compared against the AERONET Cimel reference instrument (FOV ∼ 1.2°), are fairly small. The comparison results between AOD Cimel and EKO MS-711 present a root mean square (RMS) of 0.013 (24.6 %) at 340, and 380 nm, and 0.029 (19.5 %) for longer wavelengths (440, 500, 675 and 870 nm). However, under relatively high AOD, near forward aerosol scattering might be significant because of the relatively large circumsolar radiation (CSR) due to the large EKO MS-711 FOV, resulting in a small but significant AOD underestimation in the UV range. The AOD differences decrease considerably when CSR corrections, estimated from LibRadtran radiative transfer model simulations, are performed, obtaining RMS of 0.006 (14.9 %) at 340 and 380 nm, and 0.005 (11.1 %) for longer wavelengths. The percentage of 2-minute synchronous EKO AOD–Cimel AOD differences within the World Meteorological Organization (WMO) traceability limits were ≥ 96 % at 500 nm, 675 nm and 870 nm with no CSR corrections. After applying the CSR corrections, the percentage of AOD differences within the WMO traceability limits increased to > 95 % for 380, 440, 500, 675 and 870 nm, while for 340 nm the percentage of AOD differences showed a poorer increase from 67 % to a modest 86 %.

Background Asian dust and air pollution have been recently recognized as triggers in the incidence of acute myocardial infarction. The inflow of dust from the Sahara into Spain causes an increase in particulate matter (PM) levels in the atmosphere. The proximity to the Western Coast of Morocco and the Sahara Desert promotes the seasonality arrival of natural PM on the Canary Islands (Spain), leading to high concentrations of PM with an aerodynamic diameter over 10μm (PM10). The association of dust transport from the Sahara to the Atlantic Ocean and Mediterranean areas over the incidence of acute coronary syndromes (ACS), is unknown. Purpose The aim of the present study was to elucidate whether Saharan dust events in the dust belt - Canary Islands - is associated with the incidence of ACS. Methods We retrospectively collected data of hospitalizations due to ACS in 2416 consecutive patients from a tertiary care hospital in Tenerife (Canary Islands–Spain), from December 2012 to December 2017. Taking advantage of Canary Islands location, we characterized the Saharan dust events using PMx measurements and dust modeling. Concentrations of PM10 and reactive gases are measured in the Air Quality Network of the Canary Islands by using the European reference method. We applied the time-stratified case crossover design to examine the association between Saharan dust events and the incidence of ACS. This design allows us to adjust for individual confounders, season, time trend and the day of week. Using conditional Poisson regression models, we estimated the impact of PM10 Saharan dust events on the incidence of ACS. Because the effects of Saharan dust events could persist over the course of a few days, we examined the lag effect from Day 0 to Day 5. Results The occurrence of Saharan dust events observed 0–5 days before the ACS was not significantly associated with the incidence of ACS. PM10 (μg/m3) effect was: lag 0 (IRR: 0.999, 95% CI: 0.977–1.022), lag 1 (IRR: 1.025, 95% CI: 0.988–1.063), lag 2 (IRR: 0.98, 95% CI: 0.928–1.042), lag 3 (IRR: 0.976, 95% CI: 0.944–1.011), lag 4 (IRR: 0.996, 95% CI: 0.983–1.008) and lag 5 (IRR: 0.996, 95% CI: 0.984–1.007). (Figure 1) Poisson regression model of PM10 Conclusions This negative study, the first to assess the impact of Saharan dust events as a potential trigger in the onset of ACS, shows that African dust is unlikely to be associated with the incidence of ACS.

Light transport in a dilute photonic crystal is considered. The analytical expression for the transmission coefficient is derived.Straightening of light under certain conditions in a one-dimensional photonic crystal is predicted. Such behavior is caused by the formation of a localized state in transversal motion. The main contribution to the central diffracted wave transmission coefficient is due to states, that either close to the conductance bands bottom or deeply localized in the forbidden gap. Both these states suppress mobility in the transverse direction and force light to be straightened. Straightening of light in the optical region along with small reflection make these systems very promising for use in solar cells., Comment: 8pages, 2figures

To explore whether episodes of exposure to atmospheric Saharan dust is a risk factor for hospitalization in patients with acute heart failure (AHF) attended in a hospital emergency department (ED).Single-center retrospective study of patients with AHF. The cohort was analyzed in 2 groups: ED patients hospitalized with AHF and patients discharged home from the ED. Air pollution on the 5 days leading to ED admission for AHF was recorded as the average concentration of breathable particulate matter with an aerodynamic diameter of no more than 10 µm (PM10) in the following ranges: fine PM (diameter less than 2.5 µm) or coarse PM (diameters between 2.5 and 10 µm). High Saharan dust pollution exposure was defined by mean daily PM10 concentrations between 50 and 200 µg/m3. Multivariable analysis was used to estimate risk for AHF in relation to PM10 exposure in the 5 days before the ED visit.A total of 1097 patients with AHF were treated in the ED; 318 of them (29%) were hospitalized and 779 (71%) were discharged home. Hospitalized patients were older, had more concomitant illnesses, and more episodes of exposure to Saharan dust (P.0001). Multivariable analysis confirmed the association between Saharan dust exposure and hospital admission in these patients (odds ratio, 2.36; 95% CI, 1.21-4.58; P = .01).In the absence of prospective studies, the results of this series suggest that exposure to high levels of Saharan dust (PM10 concentrations between 50 and 200 µg/m3) may be a precipitating factor for hospitalization in AHF episodes.Evaluar si la exposición a episodios de polvo sahariano predice los ingresos hospitalarios de los pacientes con insuficiencia cardiaca aguda (ICA) atendidos en un servicio de urgencias hospitalario (SUH).Estudio unicéntrico, de cohorte retrospectiva, de pacientes con ICA atendidos en un SUH. La población de estudio se dividió en 2 grupos: pacientes ingresados por ICA y pacientes con ICA dados de alta directa a domicilio desde el SUH. Se analizaron las concentraciones medias de material partículado (PMx) (respirables, diámetro aerodinámico, da10 µm), PM2,5 (finas, da2,5 µm) y PM2,5-10 (gruesas, da 2,5-10 µm) desde el día de la llegada al SUH hasta 5 días previos. Se definió exposición intensa al polvo sahariano cuando las concentraciones medias diarias de PM10 estaban entre 50 y 200 µg/m3. La relación para estimar el riesgo de ingresar por ICA en función de la exposición de PMx durante los 5 días previos a su llegada a urgencias se analizó mediante análisis multivariable.Se incluyeron 1.097 pacientes con ICA, ingresaron 318 pacientes (29%), 779 (71%) se dieron de alta. Los pacientes ingresados por ICA tenían mayor edad, elevada comorbilidad y mayor proporción de pacientes expuestos a episodios intensos de polvo sahariano (p0,0001). En el análisis multivariable la exposición a episodios de polvo sahariano intensos se relacionó con el ingreso hospitalario en los pacientes con ICA (OR = 2,36; IC 95% 1,21-4,58; p = 0,01).En ausencia de estudios prospectivos, los resultados obtenidos de la serie analizada sugieren que la presencia de concentraciones elevadas de polvo sahariano (PM10: 50-200 µg/m3) puede constituir un factor precipitante de ingreso por ICA.