The Experts below are selected from a list of 21582 Experts worldwide ranked by ideXlab platform
Lionel Soulhac - One of the best experts on this subject based on the ideXlab platform.
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the model sirane for atmospheric Urban Pollutant dispersion part iii validation against no 2 yearly concentration measurements in a large Urban agglomeration
Atmospheric Environment, 2017Co-Authors: Lionel Soulhac, Chi Vuong Nguyen, P Volta, Pietro SalizzoniAbstract:Abstract We present a validation study of an updated version of the SIRANE model, whose results have been systematically compared to concentrations of nitrogen dioxide collected over the whole Urban agglomeration of Lyon. We model atmospheric dispersion of nitrogen oxides emitted by road traffic, industries and domestic heating. The meteorological wind field is computed by a pre-processor using data collected at a ground level monitoring station. Model results are compared with hourly concentrations measured at 15 monitoring stations over the whole year (2008). Further 75 passive diffusion samplers were used during 3 periods of 2 weeks to get a detailed spatial distribution over the west part of the city. An analysis of the model results depending on the variability of the meteorological input allows us to identify the causes for peculiar bad performances of the model and to identify possible improvements of the parameterisations implemented in it.
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the model sirane for atmospheric Urban Pollutant dispersion part ii validation of the model on a real case study
Atmospheric Environment, 2012Co-Authors: Lionel Soulhac, Pietro Salizzoni, P Mejean, D Didier, I RiosAbstract:Abstract We analyse the performance of the model SIRANE by comparing its outputs to field data measured within an Urban district. SIRANE is the first Urban dispersion model based on the concept of street network, and contains specific parametrical law to explicitly simulate the main transfer mechanisms within the Urban canopy. The model validation is performed by means of field data collected during a 15 days measurement campaign in an Urban district in Lyon, France. The campaign provided information on traffic fluxes and cars emissions, meteorological conditions, background pollution levels and Pollutant concentration in different location within the district. This data set, together with complementary modelling tools needed to estimate the spatial distribution of traffic fluxes, allowed us to estimate the input data required by the model. The data set provide also the information essential to evaluate the accuracy of the model outputs. Comparison between model predictions and field measurements was performed in two ways. By evaluate the reliability of the model in simulating the spatial distribution of the Pollutant and of their time variability. The study includes a sensitivity analysis to identify the key input parameters influencing the performance of the model, namely the emissions rates and the wind velocity. The analysis focuses only on the influence of varying input parameters in the modelling chain in the model predictions and complements the analyses provided by wind tunnel studies focussing on the parameterisation implemented in the model. The study also elucidates the critical role of background concentrations that represent a significant contribution to local pollution levels. The overall model performance, measured using the Chang and Hanna (2004) criteria can be considered as ‘good’ except for NO and some of BTX species. The results suggest that improvements of the performances on NO require testing new photochemical models, whereas the improvement on BTX could be achieved by correcting their vehicular emissions factors.
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the model sirane for atmospheric Urban Pollutant dispersion part i presentation of the model
Atmospheric Environment, 2011Co-Authors: Lionel Soulhac, Pietro Salizzoni, Francoisxavier Cierco, R J PerkinsAbstract:In order to control and manage Urban air quality, public authorities require an integrated approach that incorporates direct measurements and modelling of mean Pollutant concentrations. These have to be performed by means of operational modelling tools, that simulate the transport of Pollutants within and above the Urban canopy over a large number of streets. The operational models must be able to assess rapidly a large variety of situations and with limited computing resources. SIRANE is an operational Urban dispersion model based on a simplified description of the Urban geometry that adopts parametric relations for the Pollutant transfer phenomena within and out of the Urban canopy. The streets in a city district are modelled as a network of connected street segments. The flow within each street is driven by the component of the external wind parallel to the street, and the Pollutant is assumed to be uniformly mixed within the street. The model contains three main mechanisms for transport in and out of a street: advection along the street axis, diffusion across the interface between the street and the overlying air flow and exchanges with other streets at street intersections. The dispersion of Pollutants advected or diffused out of the streets is taken into account using a Gaussian plume model, with the standard deviations σy and σz parameterised by the similarity theory. The input data for the final model are the Urban geometry, the meteorological parameters, the background concentration of Pollutants advected into the model domain by the wind and the emissions within each street in the network.
Pietro Salizzoni - One of the best experts on this subject based on the ideXlab platform.
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the model sirane for atmospheric Urban Pollutant dispersion part iii validation against no 2 yearly concentration measurements in a large Urban agglomeration
Atmospheric Environment, 2017Co-Authors: Lionel Soulhac, Chi Vuong Nguyen, P Volta, Pietro SalizzoniAbstract:Abstract We present a validation study of an updated version of the SIRANE model, whose results have been systematically compared to concentrations of nitrogen dioxide collected over the whole Urban agglomeration of Lyon. We model atmospheric dispersion of nitrogen oxides emitted by road traffic, industries and domestic heating. The meteorological wind field is computed by a pre-processor using data collected at a ground level monitoring station. Model results are compared with hourly concentrations measured at 15 monitoring stations over the whole year (2008). Further 75 passive diffusion samplers were used during 3 periods of 2 weeks to get a detailed spatial distribution over the west part of the city. An analysis of the model results depending on the variability of the meteorological input allows us to identify the causes for peculiar bad performances of the model and to identify possible improvements of the parameterisations implemented in it.
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the model sirane for atmospheric Urban Pollutant dispersion part ii validation of the model on a real case study
Atmospheric Environment, 2012Co-Authors: Lionel Soulhac, Pietro Salizzoni, P Mejean, D Didier, I RiosAbstract:Abstract We analyse the performance of the model SIRANE by comparing its outputs to field data measured within an Urban district. SIRANE is the first Urban dispersion model based on the concept of street network, and contains specific parametrical law to explicitly simulate the main transfer mechanisms within the Urban canopy. The model validation is performed by means of field data collected during a 15 days measurement campaign in an Urban district in Lyon, France. The campaign provided information on traffic fluxes and cars emissions, meteorological conditions, background pollution levels and Pollutant concentration in different location within the district. This data set, together with complementary modelling tools needed to estimate the spatial distribution of traffic fluxes, allowed us to estimate the input data required by the model. The data set provide also the information essential to evaluate the accuracy of the model outputs. Comparison between model predictions and field measurements was performed in two ways. By evaluate the reliability of the model in simulating the spatial distribution of the Pollutant and of their time variability. The study includes a sensitivity analysis to identify the key input parameters influencing the performance of the model, namely the emissions rates and the wind velocity. The analysis focuses only on the influence of varying input parameters in the modelling chain in the model predictions and complements the analyses provided by wind tunnel studies focussing on the parameterisation implemented in the model. The study also elucidates the critical role of background concentrations that represent a significant contribution to local pollution levels. The overall model performance, measured using the Chang and Hanna (2004) criteria can be considered as ‘good’ except for NO and some of BTX species. The results suggest that improvements of the performances on NO require testing new photochemical models, whereas the improvement on BTX could be achieved by correcting their vehicular emissions factors.
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the model sirane for atmospheric Urban Pollutant dispersion part i presentation of the model
Atmospheric Environment, 2011Co-Authors: Lionel Soulhac, Pietro Salizzoni, Francoisxavier Cierco, R J PerkinsAbstract:In order to control and manage Urban air quality, public authorities require an integrated approach that incorporates direct measurements and modelling of mean Pollutant concentrations. These have to be performed by means of operational modelling tools, that simulate the transport of Pollutants within and above the Urban canopy over a large number of streets. The operational models must be able to assess rapidly a large variety of situations and with limited computing resources. SIRANE is an operational Urban dispersion model based on a simplified description of the Urban geometry that adopts parametric relations for the Pollutant transfer phenomena within and out of the Urban canopy. The streets in a city district are modelled as a network of connected street segments. The flow within each street is driven by the component of the external wind parallel to the street, and the Pollutant is assumed to be uniformly mixed within the street. The model contains three main mechanisms for transport in and out of a street: advection along the street axis, diffusion across the interface between the street and the overlying air flow and exchanges with other streets at street intersections. The dispersion of Pollutants advected or diffused out of the streets is taken into account using a Gaussian plume model, with the standard deviations σy and σz parameterised by the similarity theory. The input data for the final model are the Urban geometry, the meteorological parameters, the background concentration of Pollutants advected into the model domain by the wind and the emissions within each street in the network.
J Barroso L De Aguiar - One of the best experts on this subject based on the ideXlab platform.
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incorporation of titanium dioxide nanoparticles in mortars influence of microstructure in the hardened state properties and photocatalytic activity
Cement and Concrete Research, 2013Co-Authors: S. S. Lucas, V M Ferreira, J Barroso L De AguiarAbstract:The environmental pollution in Urban areas is one of the causes for poor indoor air quality in buildings, particularly in subUrban areas. The development of photocatalytic construction materials can contribute to clean the air and improve sustainability levels. Previous studies have focused mainly in cement and concrete materials, disregarding the potential application in historic buildings. In this work, a photocatalytic additive (titanium dioxide) was added to mortars prepared with aerial lime, cement and gypsum binders. The main goal was to study the way that microstructural changes affect the photocatalytic efficiency. The photocatalytic activity was determined using a reactor developed to assess the degradation rate with a common Urban Pollutant, NOx. The laboratory results show that all the compositions tested exhibited high photocatalytic efficiency. It was demonstrated that photocatalytic mortars can be applied in new and old buildings, because the nanoadditives do not compromise the mortar hardened state properties.
R J Perkins - One of the best experts on this subject based on the ideXlab platform.
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the model sirane for atmospheric Urban Pollutant dispersion part i presentation of the model
Atmospheric Environment, 2011Co-Authors: Lionel Soulhac, Pietro Salizzoni, Francoisxavier Cierco, R J PerkinsAbstract:In order to control and manage Urban air quality, public authorities require an integrated approach that incorporates direct measurements and modelling of mean Pollutant concentrations. These have to be performed by means of operational modelling tools, that simulate the transport of Pollutants within and above the Urban canopy over a large number of streets. The operational models must be able to assess rapidly a large variety of situations and with limited computing resources. SIRANE is an operational Urban dispersion model based on a simplified description of the Urban geometry that adopts parametric relations for the Pollutant transfer phenomena within and out of the Urban canopy. The streets in a city district are modelled as a network of connected street segments. The flow within each street is driven by the component of the external wind parallel to the street, and the Pollutant is assumed to be uniformly mixed within the street. The model contains three main mechanisms for transport in and out of a street: advection along the street axis, diffusion across the interface between the street and the overlying air flow and exchanges with other streets at street intersections. The dispersion of Pollutants advected or diffused out of the streets is taken into account using a Gaussian plume model, with the standard deviations σy and σz parameterised by the similarity theory. The input data for the final model are the Urban geometry, the meteorological parameters, the background concentration of Pollutants advected into the model domain by the wind and the emissions within each street in the network.
I Rios - One of the best experts on this subject based on the ideXlab platform.
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the model sirane for atmospheric Urban Pollutant dispersion part ii validation of the model on a real case study
Atmospheric Environment, 2012Co-Authors: Lionel Soulhac, Pietro Salizzoni, P Mejean, D Didier, I RiosAbstract:Abstract We analyse the performance of the model SIRANE by comparing its outputs to field data measured within an Urban district. SIRANE is the first Urban dispersion model based on the concept of street network, and contains specific parametrical law to explicitly simulate the main transfer mechanisms within the Urban canopy. The model validation is performed by means of field data collected during a 15 days measurement campaign in an Urban district in Lyon, France. The campaign provided information on traffic fluxes and cars emissions, meteorological conditions, background pollution levels and Pollutant concentration in different location within the district. This data set, together with complementary modelling tools needed to estimate the spatial distribution of traffic fluxes, allowed us to estimate the input data required by the model. The data set provide also the information essential to evaluate the accuracy of the model outputs. Comparison between model predictions and field measurements was performed in two ways. By evaluate the reliability of the model in simulating the spatial distribution of the Pollutant and of their time variability. The study includes a sensitivity analysis to identify the key input parameters influencing the performance of the model, namely the emissions rates and the wind velocity. The analysis focuses only on the influence of varying input parameters in the modelling chain in the model predictions and complements the analyses provided by wind tunnel studies focussing on the parameterisation implemented in the model. The study also elucidates the critical role of background concentrations that represent a significant contribution to local pollution levels. The overall model performance, measured using the Chang and Hanna (2004) criteria can be considered as ‘good’ except for NO and some of BTX species. The results suggest that improvements of the performances on NO require testing new photochemical models, whereas the improvement on BTX could be achieved by correcting their vehicular emissions factors.
