Determining the Aethalometer multiple scattering enhancement factor C from the filter loading parameter.

Light-absorbing aerosols heat the atmosphere; an accurate quantification of their absorption coefficient is mandatory. However, standard reference instruments (CAPS, MAAP, PAX, PTAAM) are not always available at each measuring site around the world. By integrating all previous published studies concerning the Aethalometers, the AE33 filter loading parameter, provided by the dual-spot algorithm, were used to determine the multiple scattering enhancement factor from the Aethalometer itself (hereinafter CAE) on an yearly and a monthly basis. The method was developed in Milan, where Aethalometer measurements were compared with MAAP data; the comparison showed a good agreement in terms of equivalent black carbon (R2 = 0.93; slope = 1.02 and a negligible intercept = 0.12 µg m-3) leading to a yearly experimental multiple scattering enhancement factor of 2.51 ± 0.04 (hereinafter CMAAP). On a yearly time base the CAE values obtained using the new approach was 2.52 ± 0.01, corresponding to the experimental one (CMAAP). Considering the seasonal behavior, higher experimental CMAAP and computed CAE values were found in summer (2.83 ± 0.12) whereas, the lower ones in winter/early-spring (2.37 ± 0.03), in agreement with the single scattering albedo behavior in the Po Valley. Overall, the agreement between the experimental CMAAP and CAE showed a root mean squared error (RMSE) of just 0.038 on the CMAAP prediction, characterized by a slope close to 1 (1.001 ± 0.178), a negligible intercept (-0.002 ± 0.455) and a high degree of correlation (R2 = 0.955). From an environmental point of view, the application of a dynamic (space/time) determination of CAE increases the accuracy of the aerosol heating rate (compared to applying a fixed C value) up to 16 % solely in Milan, and to 114 % when applied in the Arctic at 80°N.

Analysis of Error Potentials generated by a lower limb exoskeleton feedback in a BMI for gait control.

Brain-machine interfaces (BMIs) based on motor imagery (MI) for controlling lower-limb exoskeletons during the gait have been gaining importance in the rehabilitation field. However, these MI-BMI are not as precise as they should. The detection of error related potentials (ErrP) as a self-tune parameter to prevent wrong commands could be an interesting approach to improve their performance. For this reason, in this investigation ErrP elicited by the movement of a lower-limb exoskeleton against subject's will is analyzed in the time, frequency and time-frequency domain and compared with the cases where the exoskeleton is correctly commanded by motor imagery (MI). The results of the ErrP study indicate that there is statistical significative evidence of a difference between the signals in the erroneous events and the success events. Thus, ErrP could be used to increase the accuracy of BMIs which commands exoskeletons.Clinical Relevance- This investigation has the purpose of improving brain-machine interfaces (BMIs) based on motor imagery (MI) by means of the detection of error potentials. This could promote the adoption of robotic exoskeletons commanded by BMIs in rehabilitation therapies.

Transfer Learning with CNN Models for Brain-Machine Interfaces to command lower-limb exoskeletons: A Solution for Limited Data.

This study evaluates the performance of two convolutional neural networks (CNNs) in a brain-machine interface (BMI) based on motor imagery (MI) by using a small dataset collected from five participants wearing a lower-limb exoskeleton. To address the issue of limited data availability, transfer learning was employed by training models on EEG signals from other subjects and subsequently fine-tuning them to specific users. A combination of common spatial patterns (CSP) and linear discriminant analysis (LDA) was used as a benchmark for comparison. The study's primary aim is to examine the potential of CNNs and transfer learning in the development of an automatic neural classification system for a BMI based on MI to command a lower-limb exoskeleton that can be used by individuals without specialized training.Clinical Relevance- BMI can be used in rehabilitation for patients with motor impairment by using mental simulation of movement to activate robotic exoskeletons. This can promote neural plasticity and aid in recovery.

Consistent determination of the heating rate of light-absorbing aerosol using wavelength- and time-dependent Aethalometer multiple-scattering correction.

Accurate and temporally consistent measurements of light absorbing aerosol (LAA) heating rate (HR) and of its source apportionment (fossil-fuel, FF; biomass-burning, BB) and speciation (black and brown Carbon; BC, BrC) are needed to evaluate LAA short-term climate forcing. For this purpose, wavelength- and time-dependent accurate LAA absorption coefficients are required. HR was experimentally determined and apportioned (sources/species) in the EMEP/ACTRIS/COLOSSAL-2018 winter campaign in Milan (urban-background site). Two Aethalometers (AE31/AE33) were installed together with a MAAP, CPC, OPC, a low volume sampler (PM2.5) and radiation instruments. AE31/AE33 multiple-scattering correction factors (C) were determined using two reference systems for the absorption coefficient: 1) 5-wavelength PP_UniMI with low time resolution (12 h, applied to PM2.5 samples); 2) timely-resolved MAAP data at a single wavelength. Using wavelength- and time-independent C values for the AE31 and AE33 obtained with the same reference device, the total HR showed a consistency (i.e. reproducibility) with average values comparable at 95% probability. However, if different reference devices/approaches are used, i.e. MAAP is chosen as reference instead of a PP_UniMI, the HR can be overestimated by 23-30% factor (by both AE31/AE33). This became more evident focusing on HR apportionment: AE33 data (corrected by a wavelength- and time-independent C) showed higher HRFF (+24 ± 1%) and higher HRBC (+10 ± 1%) than that of AE31. Conversely, HRBB and HRBrC were -28 ± 1% and -29 ± 1% lower for AE33 compared to AE31. These inconsistencies were overcome by introducing a wavelength-dependent Cλ for both AE31 and AE33, or using multi-wavelength apportionment methods, highlighting the need for further studies on the influence of wavelength corrections for HR determination. Finally, the temporally-resolved determination of C resulted in a diurnal cycle of the HR not statistically different whatever the source- speciation- apportionment used.

Aerosol optical properties in the Arctic: The role of aerosol chemistry and dust composition in a closure experiment between Lidar and tethered balloon vertical profiles.

A closure experiment was conducted over Svalbard by comparing Lidar measurements and optical aerosol properties calculated from aerosol vertical profiles measured using a tethered balloon. Arctic Haze was present together with Icelandic dust. Chemical analysis of filter samples, aerosol size distribution and a full set of meteorological parameters were determined at ground. Moreover, scanning electron microscopy coupled with energy-dispersive X-ray (SEM-EDS) data were at disposal showing the presence of several mineralogical phases (i.e., sheet silicates, gypsum, quartz, rutile, hematite). The closure experiment was set up by calculating the backscattering coefficients from tethered balloon data and comparing them with the corresponding lidar profiles. This was preformed in three subsequent steps aimed at determining the importance of a complete aerosol speciation: (i) a simple, columnar refractive index was obtained by the closest Aerosol Robotic Network (AERONET) station, (ii) the role of water-soluble components, elemental carbon and organic matter (EC/OM) was addressed, (iii) the dust composition was included. When considering the AERONET data, or only the ionic water-soluble components and the EC/OM fraction, results showed an underestimation of the backscattering lidar signal up to 76, 53 and 45% (355, 532 and 1064 nm). Instead, when the dust contribution was included, the underestimation disappeared and the vertically-averaged, backscattering coefficients (1.45 ±â€¯0.30, 0.69 ±â€¯0.15 and 0.34 ±â€¯0.08 Mm-1 sr-1, at 355, 532 and 1064 nm) were found in keeping with the lidar ones (1.60 ±â€¯0.22, 0.75 ±â€¯0.16 and 0.31 ±â€¯0.08 Mm-1 sr-1). Final results were characterized by low RMSE (0.36, 0.08 and 0.04 Mm-1 sr-1) and a high linear correlation (R2 of 0.992, 0.992 and 0.994) with slopes close to one (1.368, 0.931 and 0.977, respectively). This work highlighted the importance of all the aerosol components and of the synergy between single particle and bulk chemical analysis for the optical property characterization in the Arctic.

Laparoscopic versus Open Surgery in Complicated Appendicitis in Children Less Than 5 Years Old: A Six-Year Single-Centre Experience.

Introduction. Acute appendicitis is the most common surgical emergency in the pediatric population. The peak incidence occurs in the first decade of life, while it is uncommon to face appendicitis in children younger than 5 years of age. Laparoscopy is now demonstrated to be the optimal approach also to treat complicated appendicitis, but in very young children this standardized operation is not always easy to perform. Material and Methods. From January 2009 to December 2015 we operated on 525 acute appendicitis, with 120 patients less than 5 years of age. Results. 90 children had a complicated appendicitis (localized or diffuse peritonitis): 43 (48%) were operated on by open approach and 47 (52%) by laparoscopy. The overall incidence of postoperative complications was greater in the open appendectomy group (63% versus 26%) and all severe complications requiring reintervention (6% of cases: 3 postoperative abscesses resolved with ultrasound guided percutaneous abscess drainage; 1 tubal surgery for salpingitis; 1 adhesion-related ileus requiring relaparotomy) were mostly associated with open surgery. Conclusions. Laparoscopic surgery resulted as the best approach for treating complicated appendicitis also in younger children, with minor and less severe postoperative complications compared to open surgery.

Tinnitus and its relationship with muscle tenderness in patients with headache and facial pain.

OBJECTIVE: This study aimed to examine tinnitus prevalence in patients with different types of headache and the relationship between tinnitus and the pericranial muscle tenderness and cervical muscle tenderness scores. METHODS: A cross-sectional study was conducted of 1251 patients with migraine and/or myogenous pain, arthrogenous temporomandibular joint disorders and tension-type headache. Standardised palpation of the pericranial and cervical muscles was carried out and univariable and multivariable analysis was used to measure the odds ratio of suffering tinnitus by the different diagnoses and muscular tenderness grade. RESULTS: A univariable analysis showed that myogenous pain, pericranial muscle tenderness and cervical muscle tenderness scores, sex, and age were associated with tinnitus. When a multivariable model including only age, sex and a headache diagnosis was used, myogenous pain, migraine and age were found to be associated with tinnitus. When muscle tenderness scores were also included, only the cervical muscle tenderness and pericranial muscle tenderness scores were found to be significantly associated with tinnitus. CONCLUSION: In a population of patients with headache and craniofacial pain, tinnitus was related to increased cervical muscle tenderness and pericranial muscle tenderness scores, rather than to any particular form of headache.

Semivolatile PAH and n-alkane gas/particle partitioning using the dual model: up-to-date coefficients and comparison with experimental data.

The gas/particle partitioning coefficient K p, of a semivolatile compound is a key parameter for its atmospheric fate. The most complete method of predicting K p for polycyclic aromatic hydrocarbons (PAHs) is offered by the dual model, as it describes both the adsorption on soot and absorption into organic matter processes. However, experimental and model data exist almost exclusively for PAHs. In order to bridge this gap, experimental data on the phase partitioning of both PAHs and n-alkanes were collected at an urban and a remote site. Moreover, all the necessary parameters (e.g., octanol-air and soot-air partitioning coefficients) for the dual model have been collected and updated or (if missing) estimated for the first time. The results point out that both absorption and adsorption seem to contribute to the partitioning of PAHs and n-alkanes. However, it seems that the dual model always underestimates the particle sorption not only for PAHs but also for n-alkanes.

Data handling of GC/MS signals for characterization of PAH sources in Northern Italy aerosols.

The paper describes the characterization of polycyclic aromatic hydrocarbons (PAHs) in atmospheric aerosol samples using Gas Chromatography-Mass Spectrometry analysis. A data handling of GC/MS signals based on Experimental Autocovariance Function (EACVF) is described in order to directly characterize PAHs with a simple and reliable method suitable for processing large batches of samples. The method was successfully applied to 42 aerosol samples collected in different seasons (summer, fall and winter) in two locations in Northern Italy: Milan, a large urban area, and Oasi Le Bine, a rural site. The reliability of the EACVF results was verified by comparison with the values computed with the conventional GC/MS signal treatment and the data of independent studies. Two main emission sources were identified and described by PAH concentration profiles: the road traffic source (TR), characterized by high contributions of FLNT, PYR and CHR, and the residential combustion (COMB) mainly containing pyrogenic high molecular weight PAHs, i.e., CHR, BaP, BeP, BbF and BkF. In addition, some PAH diagnostic ratios were directly computed for the EACVF plot, to distinguish between traffic and combustion dominated emissions, i.e. the ratios CHR/BaP, PYR/BaP and PYR/BeP.

Particle size, chemical composition, seasons of the year and urban, rural or remote site origins as determinants of biological effects of particulate matter on pulmonary cells.

Particulate matter (PM), a complex mix of chemical compounds, results to be associated with various health effects. However there is still lack of information on the impact of its different components. PM2.5 and PM1 samples, collected during the different seasons at an urban, rural and remote site, were chemically characterized and the biological effects induced on A549 cells were assessed. A Partial Least Square Discriminant Analysis has been performed to relate PM chemical composition to the toxic effects observed. Results show that PM-induced biological effects changed with the seasons and sites, and such variations may be explained by chemical constituents of PM, derived both from primary and secondary sources. The first-time here reported biological responses induced by PM from a remote site at high altitude were associated with the high concentrations of metals and secondary species typical of the free tropospheric aerosol, influenced by long range transports and aging.

Sources of high PM2.5 concentrations in Milan, Northern Italy: molecular marker data and CMB modelling.

In Milan (MI), the largest city in Northern Italy, the annually average PM2.5 concentration is above 25 µg m(-3), the value that the EU established as a target for 2010, and the upper limit from 2015 onwards (2008/30/CE). Over a three-year period (2006-2009) PM concentrations and chemical compositions were measured in an urban site (MI), a rural site (OB) and a remote site (ASC) in Northern Italy. Chemical characterization (EC/OC, inorganic ions, elements, C20-C32 n-alkanes, C2-C5 mono and dicarboxylic acids, levoglucosan and PAHs) was carried out on PM2.5 samples from the three sites, and PM10 from MI. Molecular markers were used in Chemical Mass Balance (CMB) modelling to estimate the contributions of primary sources to OC, and then PM mass from each source was reconstructed in MI, OB and ASC for different seasons. Estimates of the traffic (TR) source contribution to PM2.5 mass ranged from 4.1 (± 2.0) µg m(-3) during the summer, to 13.3 (± 6.7) µg m(-3) during the winter in MI. TR was the main primary source for PM2.5 concentrations in MI (17-24%). Its contribution was lower at the OB site (7-9%) and at the remote ASC site (3-4%). TR is a local source, while biomass burning (BB) is a diffuse regional source in Northern Italy: during fall and winter, BB was 25-30% and 27-31% of PM2.5 at MI and OB respectively. Other primary sources accounted for a small amount of the PM2.5, i.e. natural gas combustion (0-1%), plant debris (0-4%), road dust (RD=0-4%; but 15% at ASC during winter and 10% of PM10 at MI during summer) and sea salt (0-1%). Secondary inorganic+organic aerosol constituted the major part of the PM2.5 mass during spring and summer (50-65%) at the three sites.

Vertical distribution of hydrocarbons in the low troposphere below and above the mixing height: tethered balloon measurements in Milan, Italy.

A novel approach for measuring vertical profiles of HCs and particle number concentrations was described and applied in the low troposphere over Milan (Italy) during typical spring and summer days. Particle profiles yielded nearly homogeneous concentrations below the mixing height, with level-to-ground concentration ratios of 92-97%, while HCs showed a more pronounced decrease (74-95%). Vertical mixing and photochemical loss of HCs were demonstrated to cause these gradients. Much lower concentrations were observed for the profiles above the mixing height, where the HC mixtures showed also a different composition, which was partially explained by the horizontal advection of air with HC sources different to those prevailing at the site. The application of pseudo-first order kinetics for reactions between HCs and the hydroxyl radical allowed for the estimation of the vertical mixing time scale in the order of 100 ± 20 min.

Vertical profiles of aerosol absorption coefficient from micro-Aethalometer data and Mie calculation over Milan.

Vertical profiles of aerosol number-size distribution and black carbon (BC) concentration were measured between ground-level and 500m AGL over Milan. A tethered balloon was fitted with an instrumentation package consisting of the newly-developed micro-Aethalometer (microAeth® Model AE51, Magee Scientific, USA), an optical particle counter, and a portable meteorological station. At the same time, PM(2.5) samples were collected both at ground-level and at a high altitude sampling site, enabling particle chemical composition to be determined. Vertical profiles and PM(2.5) data were collected both within and above the mixing layer. Absorption coefficient (b(abs)) profiles were calculated from the Aethalometer data: in order to do so, an optical enhancement factor (C), accounting for multiple light-scattering within the filter of the new microAeth® Model AE51, was determined for the first time. The value of this parameter C (2.05±0.03 at λ=880nm) was calculated by comparing the Aethalometer attenuation coefficient and aerosol optical properties determined from OPC data along vertical profiles. Mie calculations were applied to the OPC number-size distribution data, and the aerosol refractive index was calculated using the effective medium approximation applied to aerosol chemical composition. The results compare well with AERONET data. The BC and b(abs) profiles showed a sharp decrease at the mixing height (MH), and fairly constant values of b(abs) and BC were found above the MH, representing 17±2% of those values measured within the mixing layer. The BC fraction of aerosol volume was found to be lower above the MH: 48±8% of the corresponding ground-level values. A statistical mean profile was calculated, both for BC and b(abs), to better describe their behaviour; the model enabled us to compute their average behaviour as a function of height, thus laying the foundations for valid parametrizations of vertical profile data which can be useful in both remote sensing and climatic studies.

Treatment of acute appendicitis with one-port transumbilical laparoscopic-assisted appendectomy: a six-year, single-centre experience.

BACKGROUND: Laparoscopic appendectomy is a feasible and safe alternative to open appendectomy for uncomplicated appendicitis. In the past decade several laparoscopic procedures have been described using one or more ports. We report our experience in treating acute appendicitis with one-port transumbilical laparoscopic-assisted appendectomy (TULAA). PATIENTS AND METHODS: We performed 231 TULAA on patients in the period from November 2001 to September 2007. We introduced an 11 mm Hasson's port using open technique; an operative channel with 10 mm telescope and an atraumatic grasper were used. After intra-abdominal laparoscopic dissection, the appendix was exteriorised through the umbilical access. The appendectomy was performed outside the abdomen as in the open procedure; the operation was completed using only one port in 227 patients (98%), two and three ports in two patients (1%) while conversion to open surgery was needed in two patients (1%). RESULTS: The average operating time was 38 minutes and the median time to discharge was three days. Four (1, 7%) early postoperative complications (two suppuration of the umbilical wound) with no major complications were observed. CONCLUSIONS: Our results demonstrate that TULAA, which combines the advantages of both open and laparoscopic procedures, is a valid alternative form of treating uncomplicated appendicitis. If appendectomy cannot be completed with only one port, insertion of one or more ports may be necessary to safely conclude the procedure.

Indication of a deeply bound and compact K- pp state formed in the pp- -> pLambdaK+ reaction at 2.85 GeV.

We have analyzed data of the DISTO experiment on the exclusive pp --> pLambdaK+ reaction at 2.85 GeV to search for a strongly bound compact K- pp(approximately = X) state to be formed in the pp --> K+ + X reaction. The observed spectra of the K+ missing mass and the pLambda invariant-mass with high transverse momenta of p and K+ revealed a broad distinct peak of 26-sigma confidence with a mass M(X)=2267+/-3(stat)+/-5(syst) MeV/c2 and a width Gamma(X)=118+/-8(stat)+/-10(syst) MeV. The enormously large cross section indicates formation of a compact K- pp with a large binding energy of B(K)=103 MeV, which can be a possible gateway toward cold and dense kaonic nuclear matter.

Distribution of n-alkanes in the Northern Italy aerosols: data handling of GC-MS signals for homologous series characterization.

The paper describes the characterization of n-alkane homologous series present in PM samples performed by gas chromatography-mass spectrometry analysis. The PM samples were collected in three locations in northern Italy: Milan, a large urban area, Oasi Bine, a rural site far from big city centers, and Alpe San Colombano, a remote, high altitude site in the Alps. They represent different particle sizes (PM(1), PM(2.5), PM(10)) and seasons (summer, fall, and winter). The analyzed samples were characterized in terms of PM total mass, total concentration of C(20)-C(32) n-alkanes and carbon preference index, CPI, to quantify the relative abundance of odd versus even n-alkanes. As alternative to the conventional method based on peak integration, a chemometric approach based on autocovariance function (EACVF) computation was found reliable to characterize the homologous series. In particular two parameters have proven useful chemical markers for tracking the biogenic and anthropogenic origins of n-alkanes: CPI(EACVF) and series %, estimating the % n-alkanes abundance relative to total alkane concentration. The investigated samples display a large variation in the n-alkanes relative abundance: the lowest values (series % = 1-14%) were found in summer and the highest (series % = 24-48%) in winter. In addition, a considerable seasonal variation of CPI(EACVF) values can be identified for all the sampling sites: the CPI(EACVF) values are close to 1 (CPI(EACVF) = 0.8-1.2) in the cold seasons, revealing a strong contribution from anthropogenic emissions, while spreader values (CPI(EACVF) = 0.9-3) were found in the warm season, that is, reflecting a variable contribution from biogenic sources in combination with anthropogenic emissions.

The COLIPA in vitro UVA method: a standard and reproducible measure of sunscreen UVA protection.

There is a continuing need to measure and communicate reliably the UVA protection offered by commercial sunscreens. To that end, the COLIPA (European Cosmetics Trade Association) 'In Vitro Sun Protection Methods' group has developed a new in vitro method for measuring UVA protection in a standardized, reproducible manner. The method is based on in vitro UV substrate spectrophotometry and convolution of resulting absorbance data with the action spectrum for the in vivo Persistent Pigment Darkening (PPD) endpoint to provide an in vitro UVA protection factor (UVAPF) which is correlated with an in vivo measure. This method has been published as a COLIPA guideline, used currently in European geographies for testing and labelling sunscreen products. This article summarizes two 'ring' studies, involving eight separate testing laboratories, which both defined critical parameters for the method and validated it. In Ring Study 1, eight laboratories tested the in vitro UV transmission of a total of 24 sunscreens and, from the data, a unit dose of UVA (D(0) of 1.2 J cm(-2)) was defined to provide a single irradiation step which, by taking into account potential sunscreen photo-instability, gave the closest agreement with in vivo UVAPF values. In Ring Study 2, eight laboratories tested the in vitro UV transmission of a total of 13 sunscreens using this single irradiation step and established a very good correlation (r(2) = 0.83; slope = 0.84, P < 0.0001) between resulting in vitro UVAPF values and corresponding values derived from the in vivo PPD method. This new method, therefore, can be used to provide a reliable in vitro metric to describe and label UVA efficacy in sunscreen products, in line with the EU Commission recommendation 2006/247/EC.

Neumonía grave por virus influenza H1N1 / Severe pneumonia due to H1N1 flu virus

No disponible

No disponible

Sperm count of young men surgically treated for cryptorchidism in the first and second year of life: fertility is better in children treated at a younger age.

INTRODUCTION: Recent data has indicated the usefulness of performing orchiopexy in the first years of life. In this study, we evaluated testicular function in young men operated on for cryptorchidism in the first year of life. To our knowledge, this is the first report on the effects of such an early treatment. MATERIALS AND METHODS: Testicular function was assessed in a group of young men operated for cryptorchidism during the first year of life (Group A, n=13) and during the second year of life (Group B, n=16). RESULTS: Total sperm counts were clearly higher in Group A (52.3+/-14.3 million/ml vs. 30.4+/-23.5 million/ml, p=0.005) as was sperm motility (36.2+/-8.7 vs. 23.1+/-15.7%, p=0.009). A clear inverse relationship was found between age at orchiopexy and total sperm count (r=-0.394, p=0.034) and sperm motility (r=-0.382, p=0.041). The relationship between volume of testes, position at surgery, uni/bilaterality of cryptorchidism, evidence of Ad spermatogonia at biopsy performed during surgery and treatment with LHRH and hCG performed before surgery and fertility was not significant. The latter findings may be partially explained by the low number of patients participating in the study and need further investigation. CONCLUSIONS: We obtained, for the first time, results showing the benefit of treating cryptorchidism during the first year of life rather than in the second year or even later.

MODIS and OMI satellite observations supporting air quality monitoring.

Within the framework of air quality monitoring, measurements by Earth-observing satellite sensors are combined here with regional meteorological and chemical transport models. Two satellite-derived products developed within the QUITSAT project, regarding significant pollutants including PM(2.5) and NO(2), are presented. Estimates of PM(2.5) concentrations at ground level were obtained using moderate resolution imaging spectroradiometer (Terra-Aqua/NASA) aerosol optical properties. The semi-empirical approach adopted takes into account PM(2.5) sampling and meteorological descriptions of the area studied, as simulated by MM5, to infer aerosol optical properties to PM projection coefficients. Daily maps of satellite-based PM(2.5) concentrations over northern Italy are derived. Monthly average values were compared with in situ PM(2.5) samplings showing good agreement. Ozone monitoring instrument (OMI) (Aura/NASA) NO(2) tropospheric contents are merged using the GAMES chemical model simulations. The method employs a weighted rescaling of the model column in the troposphere according to the OMI observations. The weightings take into account measurement errors and model column variances within the satellite ground pixel. The obtained ground-level concentrations of NO(2) show good agreement with the environmental agencies' in situ.