90 research outputs found
Impact of the vertical emission profiles on background gas-phase pollution simulated from the EMEP emissions over Europe
International audienceFive one-year air quality simulations over a domain covering Europe have been performed using the CHIMERE chemistry transport model and the EMEP emission dataset for Europe. These five simulations differ only by the representation of the effective emission heights for anthropogenic emissions: one has been run using the EMEP standard recommendations, three others with vertical injection profiles derived from the EMEP recommendations but multiplying the injection height by 0.75, 0.50 and 0.25, respectively, while the last one uses vertical profiles derived from the recent literature. It is shown that using injection heights lower than the EMEP recommendations leads to significantly improved simulation of background SO2, NO2 and O3 concentrations when compared to the Airbase station measurements. © 2013 Author(s)
Biofiltration vs conventional activated sludge plants: what about priority and emerging pollutants removal?
International audience: This paper compares the removal performances of two complete wastewater treatment plants (WWTPs) for all priority substances listed in the Water Framework Directive and additional compounds of interest including flame retardants, surfactants, pesticides, and personal care products (PCPs) (nâ=â104). First, primary treatments such as physicochemical lamellar settling (PCLS) and primary settling (PS) are compared. Similarly, biofiltration (BF) and conventional activated sludge (CAS) are then examined. Finally, the removal efficiency per unit of nitrogen removed of both WWTPs for micropollutants is discussed, as nitrogenous pollution treatment results in a special design of processes and operational conditions. For primary treatments, hydrophobic pollutants (log K owâ>â4) are well removed (>70Â %) for both systems despite high variations of removal. PCLS allows an obvious gain of about 20Â % regarding pollutant removals, as a result of better suspended solids elimination and possible coagulant impact on soluble compounds. For biological treatments, variations of removal are much weaker, and the majority of pollutants are comparably removed within both systems. Hydrophobic and volatile compounds are well (>60Â %) or very well removed (>80Â %) by sorption and volatilization. Some readily biodegradable molecules are better removed by CAS, indicating a better biodegradation. A better sorption of pollutants on activated sludge could be also expected considering the differences of characteristics between a biofilm and flocs. Finally, comparison of global processes efficiency using removals of micropollutants load normalized to nitrogen shows that PCLSâ+âBF is as efficient as PSâ+âCAS despite a higher compactness and a shorter hydraulic retention time (HRT). Only some groups of pollutants seem better removed by PSâ+âCAS like alkylphenols, flame retardants, or di-2-ethylhexyl phthalate (DEHP), thanks to better biodegradation and sorption resulting from HRT and biomass characteristics. For both processes, and out of the 68 molecules found in raw water, only half of them are still detected in the water discharged, most of the time close to their detection limit. However, some of them are detected at higher concentrations (>1Â ÎŒg/L and/or lower than environmental quality standards), which is problematic as they represent a threat for aquatic environment
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The autophagy protein ATG9A promotes HIV-1 infectivity.
BACKGROUND: Nef is a multifunctional accessory protein encoded by HIV-1, HIV-2 and SIV that plays critical roles in viral pathogenesis, contributing to viral replication, assembly, budding, infectivity and immune evasion, through engagement of various host cell pathways. RESULTS: To gain a better understanding of the role of host proteins in the functions of Nef, we carried out tandem affinity purification-mass spectrometry analysis, and identified over 70 HIV-1 Nef-interacting proteins, including the autophagy-related 9A (ATG9A) protein. ATG9A is a transmembrane component of the machinery for autophagy, a catabolic process in which cytoplasmic components are degraded in lysosomal compartments. Pulldown experiments demonstrated that ATG9A interacts with Nef from not only HIV-1 and but also SIV (cpz, smm and mac). However, expression of HIV-1 Nef had no effect on the levels and localization of ATG9A, and on autophagy, in the host cells. To investigate a possible role for ATG9A in virus replication, we knocked out ATG9A in HeLa cervical carcinoma and Jurkat T cells, and analyzed virus release and infectivity. We observed that ATG9A knockout (KO) had no effect on the release of wild-type (WT) or Nef-defective HIV-1 in these cells. However, the infectivity of WT virus produced from ATG9A-KO HeLa and Jurkat cells was reduced by ~âfourfold and eightfold, respectively, relative to virus produced from WT cells. This reduction in infectivity was independent of the interaction of Nef with ATG9A, and was not due to reduced incorporation of the viral envelope (Env) glycoprotein into the virus. The loss of HIV-1 infectivity was rescued by pseudotyping HIV-1 virions with the vesicular stomatitis virus G glycoprotein. CONCLUSIONS: These studies indicate that ATG9A promotes HIV-1 infectivity in an Env-dependent manner. The interaction of Nef with ATG9A, however, is not required for Nef to enhance HIV-1 infectivity. We speculate that ATG9A could promote infectivity by participating in either the removal of a factor that inhibits infectivity or the incorporation of a factor that enhances infectivity of the viral particles. These studies thus identify a novel host cell factor implicated in HIV-1 infectivity, which may be amenable to pharmacologic manipulation for treatment of HIV-1 infection
A unifying framework for iterative approximate best-response algorithms for distributed constraint optimization problems
Overview of the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Forcing on the Mediterranean Climate (ChArMEx/ADRIMED) summer 2013 campaign
The Chemistry-Aerosol Mediterranean Experiment (ChArMEx; http://charmex.lsce.ipsl.fr) is a collaborative research program federating international activities to investigate Mediterranean regional chemistry-climate interactions. A special observing period (SOP-1a) including intensive airborne measurements was performed in the framework of the Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region (ADRIMED) project during the Mediterranean dry season over the western and central Mediterranean basins, with a focus on aerosol-radiation measurements and their modeling. The SOP-1a took place from 11 June to 5 July 2013. Airborne measurements were made by both the ATR-42 and F-20 French research aircraft operated from Sardinia (Italy) and instrumented for in situ and remote-sensing measurements, respectively, and by sounding and drifting balloons, launched in Minorca. The experimental setup also involved several ground-based measurement sites on islands including two ground-based reference stations in Corsica and Lampedusa and secondary monitoring sites in Minorca and Sicily. Additional measurements including lidar profiling were also performed on alert during aircraft operations at EARLINET/ACTRIS stations at Granada and Barcelona in Spain, and in southern Italy. Remote-sensing aerosol products from satellites (MSG/SEVIRI, MODIS) and from the AERONET/PHOTONS network were also used. Dedicated meso-scale and regional modeling experiments were performed in relation to this observational effort. We provide here an overview of the different surface and aircraft observations deployed during the ChArMEx/ADRIMED period and of associated modeling studies together with an analysis of the synoptic conditions that determined the aerosol emission and transport. Meteorological conditions observed during this campaign (moderate temperatures and southern flows) were not favorable to producing high levels of atmospheric pollutants or intense biomass burning events in the region. However, numerous mineral dust plumes were observed during the campaign, with the main sources located in Morocco, Algeria and Tunisia, leading to aerosol optical depth (AOD) values ranging between 0.2 and 0.6 (at 440 nm) over the western and central Mediterranean basins. One important point of this experiment concerns the direct observations of aerosol extinction onboard the ATR-42, using the CAPS system, showing local maxima reaching up to 150Mm(-1) within the dust plume. Non-negligible aerosol extinction (about 50Mm(-1)) has also been observed within the marine boundary layer (MBL). By combining the ATR- 42 extinction coefficient observations with absorption and scattering measurements, we performed a complete optical closure revealing excellent agreement with estimated optical properties. This additional information on extinction properties has allowed calculation of the dust single scattering albedo (SSA) with a high level of confidence over the western Mediterranean. Our results show a moderate variability from 0.90 to 1.00 (at 530 nm) for all flights studied compared to that reported in the literature on this optical parameter. Our results underline also a relatively low difference in SSA with values derived near dust sources. In parallel, active remote-sensing observations from the surface and onboard the F-20 aircraft suggest a complex vertical structure of particles and distinct aerosol layers with sea spray and pollution located within the MBL, and mineral dust and/or aged North American smoke particles located above (up to 6â7 km in altitude). Aircraft and balloon-borne observations allow one to investigate the vertical structure of the aerosol size distribution showing particles characterized by a large size (> 10 ÎŒm in diameter) within dust plumes. In most of cases, a coarse mode characterized by an effective diameter ranging between 5 and 10 ÎŒm, has been detected above the MBL. In terms of shortwave (SW) direct forcing, in situ surface and aircraft observations have been merged and used as inputs in 1-D radiative transfer codes for calculating the aerosol direct radiative forcing (DRF). Results show significant surface SW instantaneous forcing (up to (-90)Wm(-2) at noon). Aircraft observations provide also original estimates of the vertical structure of SW and LW radiative heating revealing significant instantaneous values of about 5 K per day in the solar spectrum (for a solar angle of 30 ) within the dust layer. Associated 3-D modeling studies from regional climate (RCM) and chemistry transport (CTM) models indicate a relatively good agreement for simulated AOD compared with observations from the AERONET/PHOTONS network and satellite data, especially for long-range dust transport. Calculations of the 3-D SW (clear-sky) surface DRF indicate an average of about -10 to -20Wm(-2) (for the whole period) over the Mediterranean Sea together with maxima (-50Wm(-2)) over northern Africa. The top of the atmosphere (TOA) DRF is shown to be highly variable within the domain, due to moderate absorbing properties of dust and changes in the surface albedo. Indeed, 3-D simulations indicate negative forcing over the Mediterranean Sea and Europe and positive forcing over northern Africa. Finally, a multiyear simulation, performed for the 2003 to 2009 period and including an oceanâatmosphere (OâA) coupling, underlines the impact of the aerosol direct radiative forcing on the sea surface temperature, OâA fluxes and the hydrological cycle over the Mediterranean.French National Research Agency (ANR)
ANR-11-BS56-0006ADEMEFrench Atomic Energy CommissionCNRS-INSU and Meteo-France through the multidisciplinary programme MISTRALS (Mediterranean Integrated Studies aT Regional And Local Scales)CORSiCA project - Collectivite Territoriale de Corse through Fonds Europeen de Developpement Regional of the European Operational ProgramContrat de Plan Etat-RegionEuropean Union's Horizon 2020 research and innovation program
654169Spanish Ministry of Economy and Competitivity
TEC2012-34575Science and Innovation
UNPC10-4E-442European Union (EU)Department of Economy and Knowledge of the Catalan Autonomous Government
SGR 583Andalusian Regional Government
P12-RNM-2409Spanish Government
CGL2013-45410-R
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In situ functionalization of a cellulosic-based activated carbon with magnetic iron oxides for the removal of carbamazepine from wastewater
The main goal of this work was to produce an easily recoverable waste-based magnetic activated carbon (MAC) for an efficient removal of the antiepileptic pharmaceutical carbamazepine (CBZ) from wastewater. For this purpose, the synthesis procedure was optimized and a material (MAC4) providing immediate recuperation from solution, remarkable adsorptive performance and relevant properties (specific surface area of 551 m2 g-1 and saturation magnetization of 39.84 emu g-1) was selected for further CBZ kinetic and equilibrium adsorption studies. MAC4 presented fast CBZ adsorption rates and short equilibrium times (<â30-45 min) in both ultrapure water and wastewater. Equilibrium studies showed that MAC4 attained maximum adsorption capacities (qm) of 68â±â4 mg g-1 in ultrapure water and 60â±â3 mg g-1 in wastewater, suggesting no significant interference of the aqueous matrix in the adsorption process. Overall, this work provides evidence of potential application of a waste-based MAC in the tertiary treatment of wastewaters.publishe
Aerosol indirect effects on summer precipitation in a regional climate model for the Euro-Mediterranean region
Aerosols affect atmospheric dynamics through their direct and
semi-direct effects as well as through their effects on cloud microphysics
(indirect effects). The present study investigates the indirect effects of
aerosols on summer precipitation in the Euro-Mediterranean region, which is
located at the crossroads of air masses carrying both natural and
anthropogenic aerosols. While it is difficult to disentangle the indirect
effects of aerosols from the direct and semi-direct effects in reality, a
numerical sensitivity experiment is carried out using the Weather Research
and Forecasting (WRF) model, which allows us to isolate indirect effects, all
other effects being equal. The Mediterranean hydrological cycle has often
been studied using regional climate model (RCM) simulations with
parameterized convection, which is the approach we adopt in the present
study. For this purpose, the Thompson aerosol-aware microphysics scheme is
used in a pair of simulations run at 50âŻkm resolution with extremely high
and low aerosol concentrations.
An additional pair of simulations has been
performed at a convection-permitting resolution (3.3âŻkm) to examine these
effects without the use of parameterized convection.
While the reduced radiative flux due to the direct effects of the aerosols is
already known to reduce precipitation amounts, there is still no general
agreement on the sign and magnitude of the aerosol indirect
forcing effect on precipitation,
with various processes competing with each other. Although some processes
tend to enhance precipitation amounts, some others tend to reduce them. In
these simulations, increased aerosol loads lead to weaker precipitation in
the parameterized (low-resolution) configuration. The fact that a similar
result is obtained for a selected area in the convection-permitting
(high-resolution) configuration allows for physical interpretations. By
examining the key variables in the model outputs, we propose a causal chain
that links the aerosol effects on microphysics to their simulated effect on
precipitation, essentially through reduction of the radiative heating of the
surface and corresponding reductions of surface temperature, resulting in
increased atmospheric stability in the presence of high aerosol loads
Aerosol forecast over the Mediterranean area during July 2013 (ADRIMED/CHARMEX)
The ADRIMED (Aerosol Direct Radiative Impact on the regional climate
in the MEDiterranean region) project was dedicated to study the atmospheric composition during
the summer 2013 in the European Mediterranean region. During its campaign
experiment part, the WRF (Weather Research and Forecast Model) and CHIMERE models were used in the forecast mode in
order to decide whether intensive observation periods should be triggered.
Each day, a simulation of 4 days was performed, corresponding to (<i>D</i>-1) to
(<i>D</i>+2) forecast leads. The goal of this study was to determine whether the
model forecast spread is lower or greater than the model biases compared to
observations. It is shown that the differences between observations and the
model are always higher than those between the forecasts. Among all forcing
types used in the chemistry-transport model, it is shown that the strong bias
and other related low forecast scores are mainly due to the forecast accuracy
of the wind speed, which is used both for the mineral dust emissions (a
threshold process) and for the long-range transport of aerosol: the surface
wind speed forecast spread can reach 50%, leading to mineral dust
emission forecast spread of up to 30%. These variations are responsible
for a moderate forecast spread of the surface PM<sub>10</sub> (a few percentage points) and
for a large spread (more than 50%) in the mineral dust concentration at
higher altitudes, leading to a mean AOD (aerosol optical depth) forecast spread of ±10%
The CHIMERE v2020r1 online chemistry-transport model
International audienceThe CHIMERE chemistry-transport model v2020r1 replaces the v2017r5 version and provides numerous novelties. The most important of these is the online coupling with the Weather Research and Forecasting (WRF) meteorological model via the OASIS3 â Model Coupling Toolkit (MCT) external coupler. The model can still be used in offline mode; the online mode enables us to take into account the direct and indirect effects of aerosols on meteorology. This coupling also enables using the meteorological parameters with sub-hourly time steps. Some new parameterizations are implemented to increase the model performance and the user's choices: dimethyl sulfide (DMS) emissions, additional schemes for secondary organic aerosol (SOA) formation with volatility basis set (VBS) and H2O, improved schemes for mineral dust, biomass burning, and sea-salt emissions. The NOx emissions from lightning are added. The model also includes the possibility to use the operator-splitting integration technique. The subgrid-scale variability calculation of concentrations due to emission activity sectors is now possible. Finally, a new vertical advection scheme has been implemented, which is able to simulate more correctly long-range transport of thin pollutant plumes
Source contributions to 2012 summertime aerosols in the Euro-Mediterranean region
In the Mediterranean area, aerosols may originate from anthropogenic or
natural emissions (biogenic, mineral dust, fire and sea salt) before
undergoing complex chemistry. In case of a huge pollution event, it is
important to know whether European pollution limits are exceeded and, if so,
whether the pollution is due to anthropogenic or natural sources. In this
study, the relative contribution of emissions to surface PM<sub>10</sub>, surface
PM<sub>2.5</sub> and total aerosol optical depth (AOD) is quantified. For Europe
and the Mediterranean regions and during the summer of 2012, the WRF and
CHIMERE models are used to perform a sensitivity analysis on a 50 km
resolution domain (from â10° W to 40° E and from
30° N to 55° N): one simulation with all sources
(reference) and all others with one source removed. The reference simulation
is compared to data from the AirBase network and two ChArMEx stations, and
from the AERONET network and the MODIS satellite instrument, to quantify the
ability of the model to reproduce the observations. It is shown that the
correlation ranges from 0.19 to 0.57 for surface particulate matter and from
0.35 to 0.75 for AOD. For the summer of 2012, the model shows that the region
is mainly influenced by aerosols due to mineral dust and anthropogenic
emissions (62 and 19 %, respectively, of total surface PM<sub>10</sub> and 17
and 52 % of total surface PM<sub>2.5</sub>). The western part of the
Mediterranean is strongly influenced by mineral dust emissions (86 % for
surface PM<sub>10</sub> and 44 % for PM<sub>2.5</sub>), while anthropogenic emissions
dominate in the northern Mediterranean basin (up to 75 % for PM<sub>2.5</sub>).
Fire emissions are more sporadic but may represent 20 % of surface
PM<sub>2.5</sub>, on average, during the period near local sources. Sea salt mainly
contributes for coastal sites (up to 29 %) and biogenic emissions mainly
in central Europe (up to 20 %).
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The same analysis was undertaken for the number of daily exceedances of the
European Union limit of 50 ÎŒg m<sup>â3</sup> for PM<sub>10</sub> (over the
stations), and for the number of daily exceedances of the WHO recommendation
for PM<sub>2.5</sub> (25 ÎŒg m<sup>â3</sup>), over the western part of Europe
and the central north. This number is generally overestimated by the model,
particularly in the northern part of the domain, but exceedances are captured
at the right time. Optimized contributions are computed with the
observations, by subtracting the background bias at each station and the
specific peak biases from the considered sources. These optimized
contributions show that if natural sources such as mineral dust and fire
events are particularly difficult to estimate, they were responsible
exclusively for 35.9 and 0.7 %, respectively, of the exceedances for
PM<sub>10</sub> during the summer of 2012. The PM<sub>25</sub> recommendation of
25 ÎŒg m<sup>â3</sup> is exceeded in 21.1 % of the cases because of
anthropogenic sources exclusively and in 0.02 % because of fires. The
other exceedances are induced by a mixed contribution between mainly mineral
dust (49.5â67 % for PM<sub>10</sub> exceedance contributions, 4.4â13.8 %
for PM<sub>2.5</sub>), anthropogenic sources (14.9â24.2 % and
46.3â80.6 %), biogenic sources (4.1â15.7 % and 12.6â30 %) and
fires (2.2â7.2 % and 1.6â12.4 %)
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