Influence of crustal dust and sea spray supermicron particle concentrations and acidity on inorganic NO_3^- aerosol during the 2013 Southern Oxidant and Aerosol Study

Inorganic aerosol composition was measured in the southeastern United States, a region that exhibits high aerosol mass loading during the summer, as part of the 2013 Southern Oxidant and Aerosol Study (SOAS) campaign. Measurements using a Monitor for AeRosols and GAses (MARGA) revealed two periods of high aerosol nitrate (NO_^3−) concentrations during the campaign. These periods of high nitrate were correlated with increased concentrations of supermicron crustal and sea spray aerosol species, particularly Na^+ and Ca^(2+), and with a shift towards aerosol with larger (1 to 2.5 μm) diameters. We suggest this nitrate aerosol forms by multiphase reactions of HNO_3 and particles, reactions that are facilitated by transport of crustal dust and sea spray aerosol from a source within the United States. The observed high aerosol acidity prevents the formation of NH_4NO_3, the inorganic nitrogen species often dominant in fine-mode aerosol at higher pH. Calculation of the rate of the heterogeneous uptake of HNO_3 on mineral aerosol supports the conclusion that aerosol NO_3^− is produced primarily by this process, and is likely limited by the availability of mineral cation-containing aerosol surface area. Modeling of NO_3^− and HNO_3 by thermodynamic equilibrium models (ISORROPIA II and E-AIM) reveals the importance of including mineral cations in the southeastern United States to accurately balance ion species and predict gas–aerosol phase partitioning

Eastern Pacific Emitted Aerosol Cloud Experiment

Aerosol–cloud–radiation interactions are widely held to be the largest single source of uncertainty in climate model projections of future radiative forcing due to increasing anthropogenic emissions. The underlying causes of this uncertainty among modeled predictions of climate are the gaps in our fundamental understanding of cloud processes. There has been significant progress with both observations and models in addressing these important questions but quantifying them correctly is nontrivial, thus limiting our ability to represent them in global climate models. The Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE) 2011 was a targeted aircraft campaign with embedded modeling studies, using the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft and the research vessel Point Sur in July and August 2011 off the central coast of California, with a full payload of instruments to measure particle and cloud number, mass, composition, and water uptake distributions. EPEACE used three emitted particle sources to separate particle-induced feedbacks from dynamical variability, namely 1) shipboard smoke-generated particles with 0.05–1-μm diameters (which produced tracks measured by satellite and had drop composition characteristic of organic smoke), 2) combustion particles from container ships with 0.05–0.2-μm diameters (which were measured in a variety of conditions with droplets containing both organic and sulfate components), and 3) aircraft-based milled salt particles with 3–5-μm diameters (which showed enhanced drizzle rates in some clouds). The aircraft observations were consistent with past large-eddy simulations of deeper clouds in ship tracks and aerosol– cloud parcel modeling of cloud drop number and composition, providing quantitative constraints on aerosol effects on warm-cloud microphysics

Primary marine aerosol-cloud interactions off the coast of California

Primary marine aerosol (PMA)-cloud interactions off the coast of California were investigated using observations of marine aerosol, cloud condensation nuclei (CCN), and stratocumulus clouds during the Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE) and the Stratocumulus Observations of Los-Angeles Emissions Derived Aerosol-Droplets (SOLEDAD) studies. Based on recently reported measurements of PMA size distributions, a constrained lognormal-mode-fitting procedure was devised to isolate PMA number size distributions from total aerosol size distributions and applied to E-PEACE measurements. During the 12 day E-PEACE cruise on the R/V Point Sur, PMA typically contributed less than 15% of total particle concentrations. PMA number concentrations averaged 12 cm^(−3) during a relatively calmer period (average wind speed 12 m/s^1) lasting 8 days, and 71 cm^(−3) during a period of higher wind speeds (average 16 m/s^1) lasting 5 days. On average, PMA contributed less than 10% of total CCN at supersaturations up to 0.9% during the calmer period; however, during the higher wind speed period, PMA comprised 5–63% of CCN (average 16–28%) at supersaturations less than 0.3%. Sea salt was measured directly in the dried residuals of cloud droplets during the SOLEDAD study. The mass fractions of sea salt in the residuals averaged 12 to 24% during three cloud events. Comparing the marine stratocumulus clouds sampled in the two campaigns, measured peak supersaturations were 0.2 ± 0.04% during E-PEACE and 0.05–0.1% during SOLEDAD. The available measurements show that cloud droplet number concentrations increased with >100 nm particles in E-PEACE but decreased in the three SOLEDAD cloud events

ERCP in Total Situs Viscerum Inversus

A 69-year-old cholecystectomized female with known total situs viscerum inversus presented recurrent colicky pain in the left upper abdominal quadrant and jaundice. Laboratory parameters showed increased neutrophils and coniugated bilirubin of 5.53 mg/dl. US and MRCP confirmed total situs viscerum inversus and a dilatation of the intra- and extrahepatic ducts with a peripapillary 13 mm stone. ERCP, sphincterotomy and successful common bile duct stone extraction were performed in the conventional way. ERCP was carried out successfully despite situs inversus maintaining the patient in the prone position with the endoscopist on the right side of the table. Some authors have reported similar cases in whom ERCP was performed in other positions, while this report shows that an experienced endoscopist can achieve the same results in the conventional way as it is possible when anatomical changes, Billroth II or Roux-en-Y, or different positions of the patient, supine or on the left side, are present

Sources, Occurrence and Characteristics of Fluorescent Biological Aerosol Particles Measured Over the Pristine Southern Ocean.

In this study, we investigate the occurrence of primary biological aerosol particles (PBAP) over all sectors of the Southern Ocean (SO) based on a 90-day data set collected during the Antarctic Circumnavigation Expedition (ACE) in austral summer 2016-2017. Super-micrometer PBAP (1-16 µm diameter) were measured by a wide band integrated bioaerosol sensor (WIBS-4). Low (3σ) and high (9σ) fluorescence thresholds are used to obtain statistics on fluorescent and hyper-fluorescent PBAP, respectively. Our focus is on data obtained over the pristine ocean, that is, more than 200 km away from land. The results indicate that (hyper-)fluorescent PBAP are correlated to atmospheric variables associated with sea spray aerosol (SSA) particles (wind speed, total super-micrometer aerosol number concentration, chloride and sodium concentrations). This suggests that a main source of PBAP over the SO is SSA. The median percentage contribution of fluorescent and hyper-fluorescent PBAP to super-micrometer SSA was 1.6% and 0.13%, respectively. We demonstrate that the fraction of (hyper-)fluorescent PBAP to total super-micrometer particles positively correlates with concentrations of bacteria and several taxa of pythoplankton measured in seawater, indicating that marine biota concentrations modulate the PBAP source flux. We investigate the fluorescent properties of (hyper-)fluorescent PBAP for several events that occurred near land masses. We find that the fluorescence signal characteristics of particles near land is much more variable than over the pristine ocean. We conclude that the source and concentration of fluorescent PBAP over the open ocean is similar across all sampled sectors of the SO

Corrigendum to "Size-resolved observations of refractory black carbon particles in cloud droplets at a marine boundary layer site" published in Atmos. Chem. Phys., 15, 1367–1383, 2015

No abstract available

Ferric chloride for enhanced coagulation and removal of enteroparasites in water

En los últimos años ha tomado relevante importancia la remoción de materia orgánica natural del agua. Está asociada a la producción de olores y gustos desagradables, constituye un sustrato para crecimiento bacteriano, incrementa la necesidad de insumos; pero lo más importante es que genera en el tratamiento de potabilización, subproductos de la desinfección potencialmente cancerígenos. Su eliminación, durante la coagulación, constituye una meta relevante en las plantas de tratamiento. Teniendo en cuenta que la coagulación es una etapa clave en la remoción de enteroparásitos, es importante evaluar si su modificación tiene alguna consecuencia en la efectividad de la eliminación de estos patógenos. Los objetivos del presente trabajo fueron: 1) Evaluar modificaciones de pH en la etapa de coagulación con cloruro férrico, a fin de optimizar la remoción de materia orgánica. 2) Comprobar si estas modificaciones afectan la eliminación de enteroparásitos. Se trabajó con equipo de laboratorio para ensayos de coagulación. Para el recuento de enteroparásitos se aplicó el método de inmunofluorescencia con anticuerpos monoclonales. Se halló que a pH más ácidos la remoción de materia orgánica es mayor Además, se comprobó que la modificación de pH no interfiere en la eliminación de quistes y ooquistes de enteroparásitos en el proceso de coagulación. Se intenta mediante este trabajo realizar aportes a fin de contribuir a disminuir los riesgos que conllevan los subproductos de la cloración, y a su vez minimizar los concernientes a la infección por parásitos.The removal of natural organic matter (NOM) from water has become greatly important. NOM is associated with the production of odors and tastes. It also provides a substrate for bacterial growth and increases chemical costs. However, the fact that it produces potentially carcinogenic disinfection by-products during drinking water treatment is the most relevant. NOM removal during coagulation is an important goal in treatment plants. Considering that coagulation is a key step in the removal of enteroparasites, it is important to evaluate whether its modification has any impact on the effective elimination of these pathogens. The objectives of this study were: 1) to evaluate pH changes in the ferric chloride coagulation stage in order to optimize NOM removal; 2) to determine whether these changes affect the elimination of enteroparasites. Laboratory equipment for coagulation tests was used. Immunofluorescence methods using monoclonal antibodies were applied for counting enteroparasites. It was found that NOM removal was increased at lower pH. It was verified that pH modification does not interfere with the removal of cysts and oocysts in enteroparasites during the coagulation process. This work was done to make a contribution to the issue of reducing the risks involved in disinfection by-products and minimizing those resulting from parasite infections.Comité de Medio Ambient

Ferric chloride for enhanced coagulation and removal of enteroparasites in water

En los últimos años ha tomado relevante importancia la remoción de materia orgánica natural del agua. Está asociada a la producción de olores y gustos desagradables, constituye un sustrato para crecimiento bacteriano, incrementa la necesidad de insumos; pero lo más importante es que genera en el tratamiento de potabilización, subproductos de la desinfección potencialmente cancerígenos. Su eliminación, durante la coagulación, constituye una meta relevante en las plantas de tratamiento. Teniendo en cuenta que la coagulación es una etapa clave en la remoción de enteroparásitos, es importante evaluar si su modificación tiene alguna consecuencia en la efectividad de la eliminación de estos patógenos. Los objetivos del presente trabajo fueron: 1) Evaluar modificaciones de pH en la etapa de coagulación con cloruro férrico, a fin de optimizar la remoción de materia orgánica. 2) Comprobar si estas modificaciones afectan la eliminación de enteroparásitos. Se trabajó con equipo de laboratorio para ensayos de coagulación. Para el recuento de enteroparásitos se aplicó el método de inmunofluorescencia con anticuerpos monoclonales. Se halló que a pH más ácidos la remoción de materia orgánica es mayor Además, se comprobó que la modificación de pH no interfiere en la eliminación de quistes y ooquistes de enteroparásitos en el proceso de coagulación. Se intenta mediante este trabajo realizar aportes a fin de contribuir a disminuir los riesgos que conllevan los subproductos de la cloración, y a su vez minimizar los concernientes a la infección por parásitos.The removal of natural organic matter (NOM) from water has become greatly important. NOM is associated with the production of odors and tastes. It also provides a substrate for bacterial growth and increases chemical costs. However, the fact that it produces potentially carcinogenic disinfection by-products during drinking water treatment is the most relevant. NOM removal during coagulation is an important goal in treatment plants. Considering that coagulation is a key step in the removal of enteroparasites, it is important to evaluate whether its modification has any impact on the effective elimination of these pathogens. The objectives of this study were: 1) to evaluate pH changes in the ferric chloride coagulation stage in order to optimize NOM removal; 2) to determine whether these changes affect the elimination of enteroparasites. Laboratory equipment for coagulation tests was used. Immunofluorescence methods using monoclonal antibodies were applied for counting enteroparasites. It was found that NOM removal was increased at lower pH. It was verified that pH modification does not interfere with the removal of cysts and oocysts in enteroparasites during the coagulation process. This work was done to make a contribution to the issue of reducing the risks involved in disinfection by-products and minimizing those resulting from parasite infections.Comité de Medio Ambient

Source-specific light absorption by carbonaceous components in the complex aerosol matrix from yearly filter-based measurements.

Understanding the sources of light-absorbing organic (brown) carbon (BrC) and its interaction with black carbon (BC) and other non-refractory particulate matter (NRPM) fractions is important for reducing uncertainties in the aerosol direct radiative forcing. In this study, we combine multiple filter-based techniques to achieve long-term, spectrally resolved, source- and species-specific atmospheric absorption closure. We determine the mass absorption efficiency (MAE) in dilute bulk solutions at 370 nm to be equal to 1.4m2 g1 for fresh biomass smoke, 0.7m2 g1 for winter-oxygenated organic aerosol (OA), and 0.13m2 g1 for other less absorbing OA. We apply Mie calculations to estimate the contributions of these fractions to total aerosol absorption. While enhanced absorption in the near-UV has been traditionally attributed to primary biomass smoke, here we show that anthropogenic oxygenated OA may be equally important for BrC absorption during winter, especially at an urban background site. We demonstrate that insoluble tar balls are negligible in residential biomass burning atmospheric samples of this study and thus could attribute the totality of the NR-PM absorption at shorter wavelengths to methanol-extractable BrC. As for BC, we show that the mass absorption cross-section (MAC) of this fraction is independent of its source, while we observe evidence for a filter-based lensing effect associated with the presence of NR-PM components. We find that bare BC has a MAC of 6.3m2 g1 at 660 nm and an absorption Ångström exponent of 0.930.16, while in the presence of coatings its absorption is enhanced by a factor of 1.4. Based on Mie calculations of closure between observed and predicted total light absorption, we provide an indication for a suppression of the filter-based lensing effect by BrC. The total absorption reduction remains modest, 10 %–20% at 370 nm, and is restricted to shorter wavelengths, where BrC absorption is significant. Overall, our results allow an assessment of the relative importance of the different aerosol fractions to the total absorption for aerosols from a wide range of sources and atmospheric ages. When integrated with the solar spectrum at 300–900 nm, bare BC is found to contribute around twothirds of the solar radiation absorption by total carbonaceous aerosols, amplified by the filter-based lensing effect (with an interquartile range, IQR, of 8 %–27 %), while the IQR of the contributions by particulate BrC is 6 %–13% (13 %–20% at the rural site during winter). Future studies that will directly benefit from these results include (a) optical modelling aiming at understanding the absorption profiles of a complex aerosol composed of BrC, BC and lensing-inducing coatings; (b) source apportionment aiming at understanding the sources of BC and BrC from the aerosol absorption profiles; (c) global modelling aiming at quantifying the most important aerosol absorbers