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AbstractUnderstanding the chemical composition of volatile organic compounds (VOCs) near emission sources and in the background atmosphere above the mixing layer height (MLH) provides insight into the fate of VOCs and is essential for developing effective air pollution control strategies. Unfortunately, knowledge of the qualitative and quantitative changes of VOCs and their vertical transport in the atmosphere is limited due to challenging experimental setups. In this study, an innovative method using tethered balloons was tested and implemented to sample 40 VOCs and O3 below and above the MLH at an industrial site in Spain. VOC and O3 samples were collected with different types of sorbent cartridges and analyzed using chromatographic techniques. Overall, a decrease in VOC concentration with altitude was observed along with a homogeneous chemical composition up to 300 m AGL. This decrease with altitude denoted the primary origin of these VOCs, which were strongly influenced by industrial processes and the traffic emissions in the area. Conversely, O3 concentrations were notably higher at balloon level and increased during nighttime temperature inversion episodes in those samples collected above the mixing layer. Ground samples contained freshly emitted pollutants of industrial origin, while balloon samples consisted of aged pollutants from traffic, other combustion sources, or from a secondary origin. This study is the first to assess the vertical composition of VOCs at a site of these characteristics and demonstrates that tethered balloons are a cost-effective method for studying air pollution dynamics from the ground to higher altitudes in the low troposphere.

In this study, we analyzed the sources of ambient PM inorganic and organic components near a cement plant using fossil fuels as well as alternative fuels, such as sewage sludge and biomass. Source apportionment methodologies, i.e., principal component analysis (PCA) and multivariate curve resolution by alternating least squares (MCR-ALS), and carbon isotope analysis (δ13C) were used to determine the potential sources and their contributions. Four sources of PM10 main tracer compounds constituents were identified: Marine and secondary inorganic aerosol, cement plant/industrial, traffic and crustal. The contributions of those sources varied significantly depending on the period of the year. However, the inorganic tracer PM species in the area were mainly released by combustion sources, namely traffic and the activity of the cement plant, especially in winter months. The analyses of tracer organic compounds also indicated combustion sources, i.e., biomass burning and fossil fuel combustion, as the predominant contributors to ambient air PM (62, 59 and 69%, in PM10, PM2.5 and PM1, respectively). Organic dust was a significant source of PM10 (33%) while its contribution was found to be minor in the finest fractions (9 and 2% in PM2.5 and PM1, respectively). Results of δ13C corroborated a significant contribution of combustion sources, traffic or biomass fuel as well as a higher influence of mineral (calcite) powder in larger particles. © Taiwan Association for Aerosol Research. ; This study was financed by the Spanish Ministry of Economy and Competitiveness (MINECO), as part of the projects CTM2012-32778 (F. S?nchez-Sober?n received a doctoral scholarship as part of the project above mentioned), CTM2015-65303 and CGL2014-57215-C4-1-R, as well as by the Catalan Government, through the projects 2014SGR90 and 2014SGR1456. The authors also want to thank LAFARGE CEMENTOS SAU for their help during the sampling. ; Peer reviewed

PM10 was collected during an EMEP winter campaign of 2017-2018 in two urban background sites in Barcelona (BCN) and Granada (GRA), two Mediterranean cities in the coast and inland, respectively. The concentrations of PM10, organic carbon (OC), elemental carbon (EC), and organic molecular tracer compounds such as hopanes, anhydro-saccharides, polycyclic aromatic hydrocarbon, and several biogenic and anthropogenic markers of secondary organic aerosols (SOA) were two times higher in GRA compared to BCN and related to the atmospheric mixing heights in the areas. Multivariate curve resolution (MCR-ALS) source apportionment analysis identified primary emissions sources (traffic + biomass burning) that were responsible for the 50% and 20% of the organic aerosol contributions in Granada and Barcelona, respectively. The contribution of biomass burning was higher in the holidays than in the working days in GRA while all primary combustion emissions decreased in holidays in BCN. The MCR-ALS identified that oxidative species and SOA formation processes contributed to 40% and 80% in Granada and Barcelona, respectively. Aged SOA was dominant in Granada and Barcelona under stagnant atmospheric conditions and in presence of air pollution. On the other hand, fresh SOA contributions from α-pinene oxidation (cis-pinonic acid) were three times higher in Barcelona than Granada and could be related to new particle formation, essentially due to overall cleaner air conditions and elevated air temperatures. ; Financial support for this study was provided by the Cooperative Programme for Monitoring and Evaluation of the Long-Range Transmission of Air Pollution in Europe (EMEP) and the European Union's Horizon 2020 research project ACTRIS2 (654109) and supported by research projects from the Plan Nacional de IyD of the Spanish Ministry of Science and Innovation INTEMPOL (PGC2018-102288-B-I00), HOUSE (CGL2016-78594-R), and BioCloud (RTI2018.101154.A.I00). IDAEA-CSIC is a Severo Ochoa Centre of Research Excellence (Spanish Ministry of Science and Innovation, CEX2018-000794-S). ; Peer reviewed

The present work assesses indoor air quality in stations of the Barcelona subway system. PM2.5 concentrations on the platforms of 4 subway stations were measured during two different seasons and the chemical composition was determined. A Positive Matrix Factorization analysis was performed to identify and quantify the contributions of major PM2.5 sources in the subway stations. Mean PM2.5 concentrations varied according to the stations design and seasonal periods. PM2.5 was composed of haematite, carbonaceous aerosol, crustal matter, secondary inorganic compounds, trace elements, insoluble sulphate and halite. Organic compounds such as PAHs, nicotine, levoglucosan and aromatic musk compounds were also identified. Subway PM2.5 source comprised emissions from rails, wheels, catenaries, brake pads and pantographs. The subway source showed different chemical profiles for each station, but was always dominated by Fe. Control actions on the source are important for the achievement of better air quality in the subway environment. © 2015 The Authors. ; The present study was supported by the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 315760 HEXACOMM, the Spanish Ministry of Economy and Competitiveness and FEDER funds ( METRO CGL2012-33066 ), and the IMPROVE LIFE project ( LIFE13 ENV/ES/000263 ). Fulvio Amato is beneficiary of an AXA Research Fund postdoctoral grant. The authors would like to thank the Transports Metropolitans de Barcelona METRO staff who arranged the sampling campaign and contributed actively to this work. Appendix A ; Peer reviewed

Background Polycyclic aromatic hydrocarbons (PAHs) have been proposed as environmental risk factors for attention deficit hyperactivity disorder (ADHD). The effects of these pollutants on brain structures potentially involved in the pathophysiology of ADHD are unknown. Objective The aim of this study was to investigate the effects of PAHs on basal ganglia volumes and ADHD symptoms in school children. Methods We conducted an imaging study in 242 children aged 8–12 years, recruited through a set of representative schools of the city of Barcelona, Spain. Indoor and outdoor PAHs and benzo[a]pyrene (BPA) levels were assessed in the school environment, one year before the MRI assessment. Whole-brain volumes and basal ganglia volumes (caudate nucleus, globus pallidus, putamen) were derived from structural MRI scans using automated tissue segmentation. ADHD symptoms (ADHD/DSM-IV Scales, American Psychiatric Association 2002) were reported by teachers, and inattentiveness was evaluated with standard error of hit reaction time in the attention network computer-based test. Results Total PAHs and BPA were associated with caudate nucleus volume (CNV) (i.e., an interquartile range increase in BPA outdoor level (67 pg/m3) and indoor level (76 pg/m3) was significantly linked to a decrease in CNV (mm3) (β = − 150.6, 95% CI [− 259.1, − 42.1], p = 0.007, and β = − 122.4, 95% CI [− 232.9, − 11.8], p = 0.030 respectively) independently of intracranial volume, age, sex, maternal education and socioeconomic vulnerability index at home). ADHD symptoms and inattentiveness increased in children with higher exposure to BPA, but these associations were not statistically significant. Conclusions Exposure to PAHs, and in particular to BPA, is associated with subclinical changes on the caudate nucleus, even below the legislated annual target levels established in the European Union. The behavioral consequences of this induced brain change were not identified in this study, but given the caudate nucleus involvement in many crucial cognitive and behavior processes, this volume reduction is concerning for the children's neurodevelopment.

Background Polycyclic aromatic hydrocarbons (PAHs) have been proposed as environmental risk factors for attention deficit hyperactivity disorder (ADHD). The effects of these pollutants on brain structures potentially involved in the pathophysiology of ADHD are unknown. Objective The aim of this study was to investigate the effects of PAHs on basal ganglia volumes and ADHD symptoms in school children. Methods We conducted an imaging study in 242 children aged 8–12 years, recruited through a set of representative schools of the city of Barcelona, Spain. Indoor and outdoor PAHs and benzo[a]pyrene (BPA) levels were assessed in the school environment, one year before the MRI assessment. Whole-brain volumes and basal ganglia volumes (caudate nucleus, globus pallidus, putamen) were derived from structural MRI scans using automated tissue segmentation. ADHD symptoms (ADHD/DSM-IV Scales, American Psychiatric Association 2002) were reported by teachers, and inattentiveness was evaluated with standard error of hit reaction time in the attention network computer-based test. Results Total PAHs and BPA were associated with caudate nucleus volume (CNV) (i.e., an interquartile range increase in BPA outdoor level (67 pg/m3) and indoor level (76 pg/m3) was significantly linked to a decrease in CNV (mm3) (β = − 150.6, 95% CI [− 259.1, − 42.1], p = 0.007, and β = − 122.4, 95% CI [− 232.9, − 11.8], p = 0.030 respectively) independently of intracranial volume, age, sex, maternal education and socioeconomic vulnerability index at home). ADHD symptoms and inattentiveness increased in children with higher exposure to BPA, but these associations were not statistically significant. Conclusions Exposure to PAHs, and in particular to BPA, is associated with subclinical changes on the caudate nucleus, even below the legislated annual target levels established in the European Union. The behavioral consequences of this induced brain change were not identified in this study, but given the caudate nucleus involvement in many crucial cognitive and behavior processes, this volume reduction is concerning for the children's neurodevelopment. © 2017 The Authors ; Marion Mortamais is supported by a Marie Sk?odowska-Curie Individual Fellowship (H2020-MSCA-IF-2014; EU project 656294). This work was supported by the European Research Council under the ERC [grant number 268479]?the BREATHE project. The Agency of University and Research Funding Management of the Catalonia Government participated in the context of Research Group SGR2014-1673. We also thank the Caixa Foundation for their financial support in the PAHs analyses. ; Peer reviewed

Background: Polycyclic aromatic hydrocarbons (PAHs) have been proposed as environmental risk factors for attention deficit hyperactivity disorder (ADHD). The effects of these pollutants on brain structures potentially involved in the pathophysiology of ADHD are unknown. Objective: The aim of this study was to investigate the effects of PAHs on basal ganglia volumes and ADHD symptoms in school children. Methods: We conducted an imaging study in 242 children aged 8–12 years, recruited through a set of representative schools of the city of Barcelona, Spain. Indoor and outdoor PAHs and benzo[a]pyrene (BPA) levels were assessed in the school environment, one year before the MRI assessment. Whole-brain volumes and basal ganglia volumes (caudate nucleus, globus pallidus, putamen) were derived from structural MRI scans using automated tissue segmentation. ADHD symptoms (ADHD/DSM-IV Scales, American Psychiatric Association 2002) were reported by teachers, and inattentiveness was evaluated with standard error of hit reaction time in the attention network computer-based test. Results: Total PAHs and BPA were associated with caudate nucleus volume (CNV) (i.e., an interquartile range increase in BPA outdoor level (67 pg/m3) and indoor level (76 pg/m3) was significantly linked to a decrease in CNV (mm3) (β = − 150.6, 95% CI [− 259.1, − 42.1], p = 0.007, and β = − 122.4, 95% CI [− 232.9, − 11.8], p = 0.030 respectively) independently of intracranial volume, age, sex, maternal education and socioeconomic vulnerability index at home). ADHD symptoms and inattentiveness increased in children with higher exposure to BPA, but these associations were not statistically significant. Conclusions: Exposure to PAHs, and in particular to BPA, is associated with subclinical changes on the caudate nucleus, even below the legislated annual target levels established in the European Union. The behavioral consequences of this induced brain change were not identified in this study, but given the caudate nucleus involvement in many crucial cognitive and behavior processes, this volume reduction is concerning for the children's neurodevelopment. ; This work was supported by the European Research Council under the ERC [grant number 268479]—the BREATHE project. The Agency of University and Research Funding Management of the Catalonia Government participated in the context of Research Group SGR2014-1673. We also thank the Caixa Foundation for their financial support in the PAHs analyses.