Towards a better characterization of submicron aerosol in the Mediterranean basin

Programa de Doctorat en Física / Tesi realitzada a l'Institut de Diagnòstic Ambiental i Estudis de l'Aigua (IDAEA - CSIC)[eng] Atmospheric aerosol is an ensemble of atmospheric pollutants with a severe impact on human health and Earth climate. Particulate Matter (PM) effects vary depending on the composition and size. However, current air quality guidelines (AQG) from WHO and from the EU Commission only define threshold standards for bulk PM10 and PM2.5 concentrations. In terms of health, the smaller the particles, the deeper they penetrate into the respiratory system, and they can even diffuse into the bloodstream and circulate to other parts of the organism. The adverse effects on the tissues in which they are deposited depend on the PM composition. Regarding climate, PM size and composition relevantly affect many aerosol-radiation direct and indirect interactions, which regulate troposphere temperature. Consequently, the consideration of these properties is relevant for present and future climate descriptions. Barcelona, the city where this study focuses, is located in the Mediterranean basin, a region with high complexity in terms of air pollution, hence, the nature of this enclave requires thorough monitoring of PM in order to protect the population from exposition accurately. This dissertation focuses on submicronic aerosol evolution over the last decade, with a more detailed study for May 2014-May 2015 and September 2017-October 2018. The objective of this thesis is to describe the PM1 sources in Barcelona by means of source apportionment (SA) techniques. The Positive Matrix Factorisation (PMF) algorithm is one of the most widely used approaches for SA and is the tool used in this dissertation. A secondary aim of this study is the improvement of the SA methodology itself. This is accomplished by testing the outcomes of new methodologies involving the more automatic analysis and dataset junction with several approaches. A field-deployed aerosol mass spectrometer was used at the Barcelona site for continuous PM1 measurements, and SA was performed on Organic Aerosol (OA). First, SA was tackled from a conventional methodology, the seasonal PMF, then, the novel rolling PMF methodology was tested and compared to the fore one. Finally, a comprehensive PM1 SA was performed based on an ensemble of different datasets coming from a variety of measurement techniques. These steps enabled a progressive aerosol composition understanding and acknowledgement of subsequent aerosol trends. A PM1 concentrations decrease was found in the 2014-2018 period, a trend confirmed by other studies at the site. Its relative composition changed significantly; a decrease was found for SO42-, BC, and NH4+, while NO3- increased and OA levels were found stable. The OA SA revealed that its sources were: secondary OA (SOA, >55-70%), road traffic OA (12-19%), cooking-like OA (14-18%), and biomass burning OA (4-6%). These sources are similar to those reported in other sites across the Mediterranean region. In this study, all the primary OA sources were found in a clear decrease from 2014 to 2018. An increasing SOA proportion and SOA oxidation state were also observed. These increments could be explained by a likely increase in the oxidation capacity of the atmosphere, related to the accumulation of oxidative radicals reported in many cities. In order to bridge the possible inter-annual variability in that period, the time period was elongated (2014-2021) detecting the same underlying trends. With the aim of further climate and health impact aerosol impact assessment, this thesis provides mid-term PM1 sources diagnosis. SOA is especially concerning in terms of health effects, hence this pollutant is to be continuously monitored to deeply understand its precursors and formation mechanisms to design effective abatement policies.[cat] L’aerosol atmosfèric és un conjunt de contaminants atmosfèrics amb un impacte sever sobre la salut humana i el clima. Els efectes del material particulat (PM) varien depenent de la seva composició i mida. Barcelona, la ciutat en què es centra aquest estudi, està localitzada a la conca mediterrània, una regió d’alta complexitat en termes de contaminació de l’aire. Per tant, requereix un monitoratge conscienciós del PM per tal de protegir la població acuradament de la seva exposició. Aquesta tesi es focalitza en l’evolució del PM submicrònic (PM1) al llarg de l’última dècada, amb un estudi més detallat per als períodes maig 2014 - maig 2015 i setembre 2017 - octubre 2018. L'objectiu d'aquesta tesi és descriure les fonts de PM1 a Barcelona per mitjà de tècniques de contribució de fonts (SA). L'algoritme de Factorització de Matriu Positiva (PMF) és un dels enfocaments més utilitzats per al SA o és l'eina emprada per a aquesta dissertació. Un objectiu secundari d'aquesta tesi és la millora de la pròpia metodologia del SA. Això és executat per mitjà del testatge a través de diferents metodologies. Les mesures de PM1 es van dur a terme a través d’un espectròmetre de masses instal·lat a l'estació de Barcelona. El SA va ser executat per a l'Aerosol Orgànic (OA) submicrònic mesurat a partir d’aquest instrument, aplicant diferents metodologies per a avaluar-ne l’exactitud. Finalment, un estudi detallat del SA de PM1 va ser executat basat en un conjunt de dades provinents de diferents tècniques de mesura. Aquests passos van permetre la comprensió progressiva de la composició i el reconeixement de les tendències subjacents de l'aerosol. Un dels resultats més rellevants consisteix en la detecció d'una tendència creixent del SOA independentment de la disminució del PM1, relacionat amb el decreixement de l'OA primari. A més, pel que fa al SA, aquesta tesi proposa diverses modificacions del protocol. El SOA és especialment preocupant pels seus efectes en la salut, per tant, aquest contaminant ha de ser contínuament monitorejat amb tècniques de SA per tal d'entendre els seus precursors i mecanismes de formació amb l'objectiu de dissenyar mesures de mitigació efectives

Towards a better characterization of submicron aerosol in the Mediterranean basin

[eng] Atmospheric aerosol is an ensemble of atmospheric pollutants with a severe impact on human health and Earth climate. Particulate Matter (PM) effects vary depending on the composition and size. However, current air quality guidelines (AQG) from WHO and from the EU Commission only define threshold standards for bulk PM10 and PM2.5 concentrations. In terms of health, the smaller the particles, the deeper they penetrate into the respiratory system, and they can even diffuse into the bloodstream and circulate to other parts of the organism. The adverse effects on the tissues in which they are deposited depend on the PM composition. Regarding climate, PM size and composition relevantly affect many aerosol-radiation direct and indirect interactions, which regulate troposphere temperature. Consequently, the consideration of these properties is relevant for present and future climate descriptions. Barcelona, the city where this study focuses, is located in the Mediterranean basin, a region with high complexity in terms of air pollution, hence, the nature of this enclave requires thorough monitoring of PM in order to protect the population from exposition accurately. This dissertation focuses on submicronic aerosol evolution over the last decade, with a more detailed study for May 2014-May 2015 and September 2017-October 2018. The objective of this thesis is to describe the PM1 sources in Barcelona by means of source apportionment (SA) techniques. The Positive Matrix Factorisation (PMF) algorithm is one of the most widely used approaches for SA and is the tool used in this dissertation. A secondary aim of this study is the improvement of the SA methodology itself. This is accomplished by testing the outcomes of new methodologies involving the more automatic analysis and dataset junction with several approaches. A field-deployed aerosol mass spectrometer was used at the Barcelona site for continuous PM1 measurements, and SA was performed on Organic Aerosol (OA). First, SA was tackled from a conventional methodology, the seasonal PMF, then, the novel rolling PMF methodology was tested and compared to the fore one. Finally, a comprehensive PM1 SA was performed based on an ensemble of different datasets coming from a variety of measurement techniques. These steps enabled a progressive aerosol composition understanding and acknowledgement of subsequent aerosol trends. A PM1 concentrations decrease was found in the 2014-2018 period, a trend confirmed by other studies at the site. Its relative composition changed significantly; a decrease was found for SO42-, BC, and NH4+, while NO3- increased and OA levels were found stable. The OA SA revealed that its sources were: secondary OA (SOA, >55-70%), road traffic OA (12-19%), cooking-like OA (14-18%), and biomass burning OA (4-6%). These sources are similar to those reported in other sites across the Mediterranean region. In this study, all the primary OA sources were found in a clear decrease from 2014 to 2018. An increasing SOA proportion and SOA oxidation state were also observed. These increments could be explained by a likely increase in the oxidation capacity of the atmosphere, related to the accumulation of oxidative radicals reported in many cities. In order to bridge the possible inter-annual variability in that period, the time period was elongated (2014-2021) detecting the same underlying trends. With the aim of further climate and health impact aerosol impact assessment, this thesis provides mid-term PM1 sources diagnosis. SOA is especially concerning in terms of health effects, hence this pollutant is to be continuously monitored to deeply understand its precursors and formation mechanisms to design effective abatement policies.[cat] L’aerosol atmosfèric és un conjunt de contaminants atmosfèrics amb un impacte sever sobre la salut humana i el clima. Els efectes del material particulat (PM) varien depenent de la seva composició i mida. Barcelona, la ciutat en què es centra aquest estudi, està localitzada a la conca mediterrània, una regió d’alta complexitat en termes de contaminació de l’aire. Per tant, requereix un monitoratge conscienciós del PM per tal de protegir la població acuradament de la seva exposició. Aquesta tesi es focalitza en l’evolució del PM submicrònic (PM1) al llarg de l’última dècada, amb un estudi més detallat per als períodes maig 2014 - maig 2015 i setembre 2017 - octubre 2018. L'objectiu d'aquesta tesi és descriure les fonts de PM1 a Barcelona per mitjà de tècniques de contribució de fonts (SA). L'algoritme de Factorització de Matriu Positiva (PMF) és un dels enfocaments més utilitzats per al SA o és l'eina emprada per a aquesta dissertació. Un objectiu secundari d'aquesta tesi és la millora de la pròpia metodologia del SA. Això és executat per mitjà del testatge a través de diferents metodologies. Les mesures de PM1 es van dur a terme a través d’un espectròmetre de masses instal·lat a l'estació de Barcelona. El SA va ser executat per a l'Aerosol Orgànic (OA) submicrònic mesurat a partir d’aquest instrument, aplicant diferents metodologies per a avaluar-ne l’exactitud. Finalment, un estudi detallat del SA de PM1 va ser executat basat en un conjunt de dades provinents de diferents tècniques de mesura. Aquests passos van permetre la comprensió progressiva de la composició i el reconeixement de les tendències subjacents de l'aerosol. Un dels resultats més rellevants consisteix en la detecció d'una tendència creixent del SOA independentment de la disminució del PM1, relacionat amb el decreixement de l'OA primari. A més, pel que fa al SA, aquesta tesi proposa diverses modificacions del protocol. El SOA és especialment preocupant pels seus efectes en la salut, per tant, aquest contaminant ha de ser contínuament monitorejat amb tècniques de SA per tal d'entendre els seus precursors i mecanismes de formació amb l'objectiu de dissenyar mesures de mitigació efectives

Lensing effect on Black Carbon particles by secondary organic aerosols and sulfates in Barcelona

Black carbon (BC) or elemental carbon (EC) is considered the second most important climate warming agent after CO2. BC is one of the components of ambient particulate matter (PM). The high absorption efficiency of BC is due to its electronic structure and composition that allows BC particles to absorb electromagnetic radiation over a wide range of wavelengths. The mass absorption crosssection (MAC) represents the efficiency that a BC particle has for absorbing light at a given wavelength and it is related to EC via eq. 1. Photochemical ageing of BC due to mixing with nonabsorbing (or less absorbing) particles, such as sulfate or organic aerosols, can increase the apparent MAC of BC above that of an uncoated BC particle.Peer reviewe

Changes in air quality during the lockdown in Barcelona (Spain) one month into the SARS-CoV-2 epidemic

Lockdown measures came into force in Spain from March 14th, two weeks after the start of the SARS-CoV-2 epidemic, to reduce the epidemic curve. Our study aims to describe changes in air pollution levels during the lockdown measures in the city of Barcelona (NE Spain), by studying the time evolution of atmospheric pollutants recorded at the urban background and traffic air quality monitoring stations. After two weeks of lockdown, urban air pollution markedly decreased but with substantial differences among pollutants. The most significant reduction was estimated for BC and NO2 (−45 to −51%), pollutants mainly related to traffic emissions. A lower reduction was observed for PM10 (−28 to −31.0%). By contrast, O3 levels increased (+33 to +57% of the 8 h daily maxima), probably due to lower titration of O3 by NO and the decrease of NOx in a VOC-limited environment. Relevant differences in the meteorology of these two periods were also evidenced. The low reduction for PM10 is probably related to a significant regional contribution and the prevailing secondary origin of fine aerosols, but an in-depth evaluation has to be carried out to interpret this lower decrease. There is no defined trend for the low SO2 levels, probably due to the preferential reduction in emissions from the least polluting ships. A reduction of most pollutants to minimal concentrations are expected for the forthcoming weeks because of the more restrictive actions implemented for a total lockdown, which entered into force on March 30th. There are still open questions on why PM10 levels were much less reduced than BC and NO2 and on what is the proportion of the abatement of pollution directly related to the lockdown, without meteorological interferences.The present work was supported by the Spanish Ministry of Agriculture, Fishing, Food and Environment, Madrid City Council and Madrid Regional Government, by the Ministry of Economy, Industry and Competitiveness and FEDER funds under the project HOUSE (CGL2016-78594-R), and by the Generalitat de Catalunya (AGAUR 2015 SGR33), and by the Spanish Ministry of Sciences, Innovation and Universities (EQC2018-004598-P).Peer reviewe

Compositional changes of PM2.5 in NE Spain during 2009–2018: a trend analysis of the chemical composition and source apportionment

In this work, time-series analyses of the chemical composition and source contributions of PM2.5 from an urban background station in Barcelona (BCN) and a rural background station in Montseny (MSY) in northeastern Spain from 2009 to 2018 were investigated and compared. A multisite positive matrix factorization analysis was used to compare the source contributions between the two stations, while the trends for both the chemical species and source contributions were studied using the Theil–Sen trend estimator. Between 2009 and 2018, both stations showed a statistically significant decrease in PM2.5 concentrations, which was driven by the downward trends of levels of chemical species and anthropogenic source contributions, mainly from heavy oil combustion, mixed combustion, industry, and secondary sulfate. These source contributions showed a continuous decrease over the study period, signifying the continuing success of mitigation strategies, although the trends of heavy oil combustion and secondary sulfate have flattened since 2016. Secondary nitrate also followed a significant decreasing trend in BCN, while secondary organic aerosols (SOA) very slightly decreased in MSY. The observed decreasing trends, in combination with the absence of a trend for the organic aerosols (OA) at both stations, resulted in an increase in the relative proportion of OA in PM2.5 by 12% in BCN and 9% in MSY, mostly from SOA, which increased by 7% in BCN and 4% in MSY. Thus, at the end of the study period, OA accounted for 40% and 50% of the annual mean PM2.5 at BCN and MSY, respectively. This might have relevant implications for air quality policies aiming at abating PM2.5 in the study region and for possible changes in toxicity of PM2.5 due to marked changes in composition and source apportionment

Protective factors of ethical conflict during a pandemic-quali-ethics-COVID-19 research part 2: an international qualitative study

Aims and Objectives: To determine which factors can be considered protective ofethical conflicts in intensive care unit healthcare professionals during a pandemic. Background: The COVID-19 pandemic gave rise to new ethical concerns in relation to the management of public health and the limitations on personal freedom. Continued exposure to ethical conflict can have a range of psychological consequences.Design: A qualitative design based on phenomenological approach.Methods: A total of 38 nurses and physicians who were regular staff members of Barcelona and Milan's public tertiary university hospitals and working in intensive care units during the first wave of the COVID-19 pandemic. Semi-structured online indepth interviews were conducted. A thematic analysis was performed by two independent researchers following the seven steps of Colaizzi's methods. We adhere COREQ guidelines.Results: One theme 'Protective factors of ethical conflict in sanitary crisis' and four subthemes emerged from the data: (1) knowledge of the infectious disease, (2) good communication environment, (3) psychological support and (4) keeping the same work team together. Conclusions: Four elements can be considered protective factors of ethical conflict for healthcare professionals during a sanitary crisis. While some of these factors have already been described, the joint identification of this set of four factors as a single element is, in itself, novel. This should help in ensuring the right mechanisms are inplace to face future pandemics and should serve to improve institutional organisation and guarantee safe and high-quality patient care in times of heath care crisis. Relevance to Clinical Practice: Future strategies for the prevention of ethical conflict during sanitary crises, pandemics or other catastrophes need to consider a set of four factors as a single element. These factors are the knowledge of the infectious disease,a good communication environment, psychological support and keeping the same work team together into joint consideration

Guia de medicaments d’Atenció Primària que requereixen una vigilància especial per la seva dispensació en pacients amb funció renal disminuïda.

Projecte: AVCRI 279 Requeriments tècnics: L’entorn és l’EXCEL de Microsoft. L'accés al codi no estarà disponible fins la fi de la data d'embargament. Si esteu interessats a accedir-hi, contacteu amb idea(at)fbg.ub.eduAquesta Base de Dades (Guia de Medicaments) recull informació per tal d’indicar quins medicaments són susceptibles d'ajustos de dosi per evitar la iatrogènia medicamentosa en pacients amb deteriorament de la funció renal. Aquesta informació s'ha consensuat entre farmacèutics i metges nefròlegs a partir de la informació disponible en diferents bases de dades nacionals i internacionals. Per agilitzar l'ús de la Guia s'ha consensuat categoritzar en nivell baix, moderat o alt el risc que suposa pel pacient l’ús d'aquests medicaments segons el seu filtrat glomerular. A més la Guia recull els ajustos de dosi a realitzar, les interaccions medicamentoses i la simptomatologia per sobre dosificació en pacients amb funció renal disminuïda. A partir d'aquesta Base de Dades, s'ha dissenyat una aplicació web que facilita al professional sanitari la presa de decisions per a l'ajust de dosis de medicaments en funció del filtrat glomerular del pacient

Macromolecular crowding upon in-vivo-like enzyme-kinetics: effect of enzyme-obstacle size ratio

In the present work, the volume exclusion phenomenon, also known as macromolecular crowding, has been applied to the field of enzyme kinetics. It has been approached by adding polymeric obstacles in the media of different enzymatic reactions. The concentration and size of these obstacles have been changed systematically in order to obtain kinetic information about each reaction. Results indicate that the performance of a certain enzyme always depends on the amount of excluded volume. However, only large, oligomeric proteins display an obstacle size-dependent behavior. Besides, crowding can hinder diffusion to the extent of being capable of shifting reaction control from activation to diffusion

Molecular in-depth on the epidemiological expansion of SARS-CoV-2 XBB.1.5

Since the beginning of the pandemic, the generation of new variants periodically recurs. The XBB.1.5 SARS-CoV-2 variant is one of the most recent. This research was aimed at verifying the potential hazard of this new subvariant. To achieve this objective, we performed a genome-based integrative approach, integrating results from genetic variability/phylodynamics with structural and immunoinformatic analyses to obtain as comprehensive a viewpoint as possible. The Bayesian Skyline Plot (BSP) shows that the viral population size reached the plateau phase on 24 November 2022, and the number of lineages peaked at the same time. The evolutionary rate is relatively low, amounting to 6.9 × 10−4 subs/sites/years. The NTD domain is identical for XBB.1 and XBB.1.5 whereas their RBDs only differ for the mutations at position 486, where the Phe (in the original Wuhan) is replaced by a Ser in XBB and XBB.1, and by a Pro in XBB.1.5. The variant XBB.1.5 seems to spread more slowly than sub-variants that have caused concerns in 2022. The multidisciplinary molecular in-depth analyses on XBB.1.5 performed here does not provide evidence for a particularly high risk of viral expansion. Results indicate that XBB.1.5 does not possess features to become a new, global, public health threat. As of now, in its current molecular make-up, XBB.1.5 does not represent the most dangerous variant