Characteristics And Temporal Variations Of Organic And Elemental Carbon Aerosols In A High–Altitude, Tropical Latin American Megacity

Bogota is a Latin American megacity located at an average altitude of 2600 m in the tropical Andes. It registers frequent episodes of poor air quality due to high PM10 concentrations. The carbonaceous fraction is the main PM10 component (>50%), but there is a lack of specific studies analyzing the characteristics and temporal variability of organic carbon (OC) and elemental carbon (EC) aerosols. In this study, daily samples (24±1h) were collected from June 2015 to May 2016 (a total of 308 samples) at an urban background site during an El Niño year, and the quartz filters were analyzed using a thermal-optical method. Results showed that EC and organic matter accounted for ~60% of the PM10 mass. The OC and EC averages were 8.92 ± 4.52 μg/m3 and 3.25 ± 1.59 μg/m3, respectively. The months with the highest average OC values were January to March, while EC concentrations were relatively constant throughout the year. Regarding daily values, the highest mean concentrations of OC (10.2 ± 5.13 μg/m3) and EC (3.73 ± 1.74 μg/m3) were obtained on Thursdays, and the lowest on Sundays (OC = 6.67 ± 3.04 μg/m3 and EC = 2.46 ± 0.94 μg/m3). The OC/EC ratio ranged from 1.66 (June) to 4.88 (March), with an annual average of 3.16 ± 2.01. The secondary organic carbon (SOC) contributions, measured using the EC-tracer method, accounted for 45% of the total OC. The effective carbon ratio, which indicates an association between carbonaceous particles and climate change, ranged from 0.12 (July) to 0.74 (May). The study of air-mass origins revealed that days with air mass from E + NE registered the highest OC concentrations. This research provides new data on the variability of carbonaceous aerosols over the course of a year. It also highlights forest fires as a significant source of OC and EC, and indicates the high impact of SOC on OC concentration at the sampling site

Physicochemical Characterization And Sources Of The Thoracic Fraction Of Road Dust In A Latin American Megacity

Road dust has been identified as one of the main sources of outdoor PM10 in Bogota (a Latin American megacity), but there are no studies that have analyzed the physicochemical characteristics and origins of its respirable fraction. A characterization of inorganic compounds (water soluble ions, major and trace elements, organic and elemental carbon) and an analysis of source contributions to the PM10 fraction of road dust were carried out in this study. A total of twenty road dust samples, selected from representative industrial, residential and commercial areas, were swept and resuspended to obtain the thoracic fraction. Size distribution by laser diffraction and individual particle morphology by Scanning Electron Microscopy were also evaluated. The data obtained revealed that the volume (%) of thoracic particles was higher in samples from industrial zones where heavy vehicular traffic, industrial emissions and deteriorated pavements predominated. Crustal elements were the most abundant species, accounting for 49–62% of the thoracic mass, followed by OC (13–29%), water-soluble ions (1.4–3.8%), EC (0.8–1.9%) and trace elements (0.2–0.5%). The Coefficient of Divergence was obtained to identify the spatial variability of the samples. A source apportionment analysis was carried out considering the variability of chemical profiles, enrichment factors and ratios of Fe/Al, K/Al, Ca/Al, Ti/Al, Cu/Sb, Zn/Sb, OC/TC and OC/EC. By means of a PCA analysis, five components were identified, including local soils and pavement erosion (63%), construction and demolition activities (13%), industrial emissions (6%), brake wear (5%) and tailpipe emissions (4%). These components accounted for 91% of the total variance. The results provide data to understand better one of the main sources of PM10 emissions in Bogota, such as road dust. These data will be useful to optimize environmental policies, and they may be used in future studies of human health and air quality modeling

MEGARA cryogenic system

MEGARA (Multi Espectrógrafo en GTC de Alta Resolución para Astronomía) is the new integral field unit (IFU) and multi-object spectrograph (MOS) instrument for the Gran Telescopio Canarias (GTC). The selected cryogenic device to harbor the CCD detector for the MEGARA spectrograph is a liquid nitrogen open-cycle cryostat. The LN2 open-cycle cryostat is a custom made product which has been designed by the INAOE astronomical instrumentation group. The proposed cryostat offers modular stages for easy assembly and testing whilst also allowing future modifications to accommodate the required CCDs, electronics and optics

Forest Fires, Land Use Changes and Their Impact on Hydrological Balance in Temperate Forests of Central Mexico

Temperate forests play a fundamental role in the provision, regulation, and support of hydrological environmental services, but they are subject to constant changes in land use (clearing, overgrazing, deforestation, and forest fires) that upset the hydrological balance. Through scenarios simulated with the Water Evaluation and Planning (WEAP) hydrological model, the present study analyzes the effects of forest fires and land use changes on the hydrological balance in the microwatersheds of central Mexico. The land use changes that took place between 1995 and 2021 were estimated, and projections based on the current scenario were made. Two trend scenarios were proposed for 2047: one with a positive trend (forest permanence) and the other with a negative trend (loss of cover from forest fires). The results show that with permanence or an increase in forest area, the surface runoff would decrease by 48.2%, increasing the base flow by 37% and the soil moisture by 2.3%. If forest is lost, surface runoff would increase up to 454%, and soil moisture would decrease by 27%. If the current forest decline trends continue, then there will be negative alterations in hydrological processes: a reduction in the interception of precipitation by the canopy and an increase in the velocity and flow of surface runoff, among others. The final result will be a lower amount of water being infiltrated into the soil and stored in the subsoil. The provision of hydrological environmental services depends on the maintenance of forest cover

Lessons from the COVID-19 air pollution decrease in Spain: Now what?

We offer an overview of the COVID-19 -driven air quality changes across 11 metropolises in Spain with the focuson lessons learned on how continuing abating pollution. Trafficflow decreased by up to 80% during the lockdownand remained relatively low during the full relaxation (June and July). After the lockdown a significant shift frompublic transport to private vehicles (+21% in Barcelona) persisted due to the pervasive fear that using publictransport might increase the risk of SARS-CoV-2 infection, which need to be reverted as soon as possible. NO2levels fell below 50% of the WHO annual air quality guidelines (WHOAQGs), but those of PM2.5were reducedless than expected due to the lower contributions from traffic, increased contributions from agricultural and do-mestic biomass burning, or meteorological conditions favoring high secondary aerosol formation yields. Evenduring the lockdown, the annual PM2.5WHOAQG was exceeded in cities within the NE and E regions withhigh NH3emissions from farming and agriculture. Decreases in PM10levels were greater than in PM2.5due to reduced emissions from road dust, vehicle wear, and construction/demolition. Averaged O3daily maximum 8-h(8hDM) experienced a generalized decrease in the rural receptor sites in the relaxation (June–July) with−20%reduced mobility. For urban areas O38hDM responses were heterogeneous, with increases or decreases depend-ing on the period and location. Thus, after canceling out the effect of meteorology, 5 out of 11 cities experiencedO3decreases during the lockdown, while the remaining 6 either did not experience relevant reductions or in-creased. During the relaxation period and coinciding with the growing O3season (June–July), most cities expe-rienced decreases. However, the O3WHOAQG was still exceeded during the lockdown and full relaxationperiods in several cities. For secondary pollutants, such as O3and PM2.5, further chemical and dispersion model-ing along with source apportionment techniques to identify major precursor reduction targets are required toevaluate their abatement potential

Nutrición enteral domiciliaria en España: registro Nadya del año 2011-2012

Objective: To describe the results of the home enteral nutrition (HEN) registry of the NADYA-SENPE group in 2011 and 2012. Material and methods: We retrieved the data of the patients recorded from January 1st 2011 to December 31st 2012. Results: There were 3021 patients in the registry during the period from 29 hospitals, which gives 65.39 per million inhabitants. 97.95% were adults, 51.4% male. Mean age was 67.64 ± 19.1, median age was 72 years for adults and 7 months for children. Median duration with HEN was 351 days and for 97.5% was their first event with HEN. Most patients had HEN because of neurological disease (57.8%). Access route was nasogastric tube for 43.5% and gastrostomy for 33.5%. Most patients had limited activity level and, concerning autonomy, 54.8% needed total help. Nutritional formula was supplied from chemist’s office to 73.8% of patients and disposables, when necessary, was supplied from hospitals to 53.8% of patients. HEN was finished for 1,031 patients (34.1%) during the period of study, 56.6% due to decease and 22.2% due to recovery of oral intake. Conclusions: Data from NADYA-SENPE registry must be explained cautiously because it is a non-compulsory registry. In spite of the change in the methodology of the registry in 2010, tendencies regarding HEN have been maintained, other than oral routeObjetivos: Describir los resultados del registro de nutrición enteral domiciliaria (NED) del grupo NADYASENPE de los años 2011 y 12. Material y métodos: Se recopilaron los datos introducidos en el registro desde el 1 de enero de 2011 al 31 de diciembre de 2012. Resultados: Hubo 3021 pacientes en el registro durante el periodo, procedentes de 29 hospitales, lo que da una prevalencia de 65,39 casos por millón de habitantes. 97.95% fueron adultos, 51,4% varones. La edad media fue 67,64 ± 19,1 años y la mediana 72 años para los adultos y 7 meses para los niños. La duración media de la NED fue 351 días y para el 97,5% fue el primer episodio con NED. La mayoría de pacientes tenían NED por una enfermedad neurológica (57,8%). La vía de acceso fue sonda nasogástrica para el 43,5% y gastrostomía para el 33,5%. La mayoría de pacientes tuvieron un nivel de actividad física limitado y, respecto a la autonomía, 54,8% necesitaba ayuda total. La fórmula de nutrición se suministró desde las oficinas de farmacia para el 73,8% y los fungibles, cuando fueron necesarios, desde los hospitales para el 53,8%. La NED se suspendió en 1.031 pacientes (34,1%) durante el periodo de estudio, 56,6% debido a fallecimiento y 22,2% debido a recuperación de la vía oral. Conclusiones: Los datos del registro NADYA-SENPE deben ser interpretados con precaución ya que se trata de un registro voluntario. A pesar del cambio de metodología del registro en 2010, las tendencias en NED se han mantenido, salvo la importancia cuantitativa de la vía ora

A genome-wide association study follow-up suggests a possible role for PPARG in systemic sclerosis susceptibility

Introduction: A recent genome-wide association study (GWAS) comprising a French cohort of systemic sclerosis (SSc) reported several non-HLA single-nucleotide polymorphisms (SNPs) showing a nominal association in the discovery phase. We aimed to identify previously overlooked susceptibility variants by using a follow-up strategy.<p></p> Methods: Sixty-six non-HLA SNPs showing a P value <10-4 in the discovery phase of the French SSc GWAS were analyzed in the first step of this study, performing a meta-analysis that combined data from the two published SSc GWASs. A total of 2,921 SSc patients and 6,963 healthy controls were included in this first phase. Two SNPs, PPARG rs310746 and CHRNA9 rs6832151, were selected for genotyping in the replication cohort (1,068 SSc patients and 6,762 healthy controls) based on the results of the first step. Genotyping was performed by using TaqMan SNP genotyping assays. Results: We observed nominal associations for both PPARG rs310746 (PMH = 1.90 × 10-6, OR, 1.28) and CHRNA9 rs6832151 (PMH = 4.30 × 10-6, OR, 1.17) genetic variants with SSc in the first step of our study. In the replication phase, we observed a trend of association for PPARG rs310746 (P value = 0.066; OR, 1.17). The combined overall Mantel-Haenszel meta-analysis of all the cohorts included in the present study revealed that PPARG rs310746 remained associated with SSc with a nominal non-genome-wide significant P value (PMH = 5.00 × 10-7; OR, 1.25). No evidence of association was observed for CHRNA9 rs6832151 either in the replication phase or in the overall pooled analysis.<p></p> Conclusion: Our results suggest a role of PPARG gene in the development of SSc

Material particulado en España: niveles, composición y contribución de fuentes

El estudio llevado a cabo en un elevado número de emplazamientos de medida de material particulado (PM) en España ha permitido determinar las importantes variaciones que se producen en los niveles medios de concentración de PM10 y PM2,5 y en su composición química, entre sus distintas regiones geográficas. En diferentes entornos industriales y de tráfico considerados “hotspots”, los niveles medios de PM10 registrados llegan a superar normalmente los valores límite de concentración recomendados. La variabilidad existente entre los distintos emplazamientos de medida en lo que se refiere a niveles de concentración de PM y a la superación de los valores límite de concentración está relacionada con la existencia de distintos patrones, tanto de emisión de las fuentes de material particulado naturales y antropogénicas, como patrones climáticos y de reactividad/ estabilidad de algunas especies presentes en la composición del PM.Este estudio ha sido financiado mediante convenios de colaboración de la Dirección General de Calidad y Evaluación Ambiental del Ministerio de Medio Ambiente y del Plan Nacional de I+D del Ministerio de Educación y Ciencia (CGL2004-05984_C07-02/CLI, REN2001-0659-C03-03), y contratos de investigación respaldados por Comunidades Autónomas de Andalucía, Cataluña, Madrid, y Valencia