Air quality modelling, simulation, and computational methods: a review

2013 ◽  
Vol 21 (3) ◽  
pp. 149-179 ◽  
Author(s):  
Mohanad El-Harbawi
Keyword(s):  
Air Quality ◽  
Computational Methods ◽  
Atmospheric Chemistry ◽  
Web Sites ◽  
Remote Sensing Data ◽  
Reference Source ◽  
Air Quality Modelling ◽  
Quality Models ◽  
Wide Range ◽  
Recent Developments

The objective of this paper is to provide a comprehensive theoretical review with regard to history, existing approaches, recent developments, major research, associated computational methods, and applications of air quality models. A wide range of topics is covered, focusing on sources of air pollution, primary and secondary pollutants, atmospheric chemistry, atmospheric chemical transport models, computer programs for dispersion modelling, online and offline air quality modelling, data assimilation, parallel computing, applications of geographic information system in air quality modelling, air quality index, as well as the use of satellite and remote sensing data in air quality modelling. Each of these elements is comprehensively discussed, covered, and reviewed with respect to various literature and methods related to air quality modelling and applications. Several major commercial and noncommercial dispersion packages are extensively reviewed and detailed advantages and limitations of their applications are highlighted. The paper includes several comparison summaries among various models used in air quality study. Furthermore, the paper provides useful web sites, where readers can obtain further information regarding air quality models and (or) software. Lastly, current generation of air quality models and future directions are also discussed. This paper may serve as a compendium for scientists who work in air quality modelling field. Some topics are generally treated; therefore, the paper may also be used as a reference source by many scientists working with air quality modelling.

scholarly journals VISUALISING URBAN AIR QUALITY USING AERMOD, CALPUFF AND CFD MODELS: A CRITICAL REVIEW

2020 ◽  
Vol XLIV-4/W3-2020 ◽  
pp. 355-363
Author(s):  
N. Ridzuan ◽  
U. Ujang ◽  
S. Azri ◽  
T. L. Choon
Keyword(s):  
Air Quality ◽  
Urban Area ◽  
Air Pollutants ◽  
Dispersion Model ◽  
Ambient Air ◽  
Urban Air Quality ◽  
Urban Air ◽  
Air Quality Modelling ◽  
Modeling Tools ◽  
Wide Range

Abstract. Degradation of air quality level can affect human’s health especially respiratory and circulatory system. This is because the harmful particles will penetrate into human’s body through exposure to surrounding. The existence of air pollution event is one of the causes for air quality to be low in affected urban area. To monitor this event, a proper management of urban air quality is required to solve and reduce the impact on human and environment. One of the ways to manage urban air quality is by modelling ambient air pollutants. So, this paper reviews three modelling tools which are AERMOD, CALPUFF and CFD in order to visualise the air pollutants in urban area. These three tools have its own capability in modelling the air quality. AERMOD is better to be used in short range dispersion model while CALPUFF is for wide range of dispersion model. Somehow, it is different for CFD model as this model can be used in wide range of application such as air ventilation in clothing and not specifically for air quality modelling only. Because of this, AERMOD and CALPUFF model can be classified in air quality modelling tools group whereas CFD modelling tool is classified into different group namely a non-specific modelling tool group which can be implemented in many fields of study. Earlier air quality researches produced results in two-dimensional (2D) visualization. But there are several of disadvantages for this technique. It cannot provide height information and exact location of pollutants in three-dimensional (3D) as perceived in real world. Moreover, it cannot show a good representation of wind movement throughout the study area. To overcome this problem, the 3D visualization needs to be implemented in the urban air quality study. Thus, this paper intended to give a better understanding on modeling tools with the visualization technique used for the result of performed research.

Evaluation of aromatic oxidation reactions in seven chemical mechanisms with an outdoor chamber

2013 ◽  
Vol 10 (3) ◽  
pp. 245 ◽  
Author(s):  
Harshal M. Parikh ◽  
Harvey E. Jeffries ◽  
Ken G. Sexton ◽  
Deborah J. Luecken ◽  
Richard M. Kamens ◽  
...  
Keyword(s):  
Air Quality ◽  
Aromatic Ring ◽  
Aromatic Hydrocarbons ◽  
Urban Areas ◽  
Ring Opening ◽  
Chamber Wall ◽  
Oxidation Reactions ◽  
Quality Models ◽  
Chemical Mechanisms ◽  
Wide Range

Environmental context Regulatory air quality models used to develop strategies to reduce ozone and other pollutants must be able to accurately predict ozone produced from aromatic hydrocarbons. In urban areas, major sources of aromatic hydrocarbons are gasoline and diesel-powered vehicles. Our findings show that the representation of aromatic hydrocarbon chemistry in air quality models is an area of high uncertainty Abstract Simulations using seven chemical mechanisms are intercompared against O3, NOx and hydrocarbon data from photooxidation experiments conducted at the University of North Carolina outdoor smog chamber. The mechanisms include CB4–2002, CB05, CB05-TU, a CB05 variant with semi-explicit aromatic chemistry (CB05RMK), SAPRC07, CS07 and MCMv3.1. The experiments include aromatics, unsaturated dicarbonyls and volatile organic compound (VOC) mixtures representing a wide range of urban environments with relevant hydrocarbon species. In chamber simulations the sunlight is characterised using new solar radiation modelling software. A new heterogeneous chamber wall mechanism is also presented with revised chamber wall chemical processes. Simulations from all mechanisms, except MCMv3.1, show median peak O3 concentration relative errors of less than 25% for both aromatic and VOC mixture experiments. Although MCMv3.1 largely overpredicts peak O3 levels, it performs relatively better in predicting the peak NO2 concentration. For aromatic experiments, all mechanisms except CB4–2002, largely underpredict the NO–NO2 crossover time and over-predict both the absolute NO degradation slope and the slope of NO2 concentration rise. This suggests a major problem of a faster and earlier NO to NO2 oxidation rate across all the newer mechanisms. Results from individual aromatic and unsaturated dicarbonyl experiments illustrate the unique photooxidation chemistry and O3 production of several aromatic ring-opening products. The representation of these products as a single mechanism species in CB4–2002, CB05 and CB05-TU is not adequate to capture the O3 temporal profile. In summary, future updates to chemical mechanisms should focus on the chemistry of aromatic ring-opening products.

scholarly journals Global sea-surface iodide observations, 1967–2018

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Rosie J. Chance ◽  
Liselotte Tinel ◽  
Tomás Sherwen ◽  
Alex R. Baker ◽  
Thomas Bell ◽  
...  
Keyword(s):  
Air Quality ◽  
Observational Data ◽  
Atmospheric Chemistry ◽  
Tropospheric Ozone ◽  
Sea Surface ◽  
Digital Form ◽  
Quality Models ◽  
Surface Ocean ◽  
Data Points ◽  
Global Surface

AbstractThe marine iodine cycle has significant impacts on air quality and atmospheric chemistry. Specifically, the reaction of iodide with ozone in the top few micrometres of the surface ocean is an important sink for tropospheric ozone (a pollutant gas) and the dominant source of reactive iodine to the atmosphere. Sea surface iodide parameterisations are now being implemented in air quality models, but these are currently a major source of uncertainty. Relatively little observational data is available to estimate the global surface iodide concentrations, and this data has not hitherto been openly available in a collated, digital form. Here we present all available sea surface (<20 m depth) iodide observations. The dataset includes values digitised from published manuscripts, published and unpublished data supplied directly by the originators, and data obtained from repositories. It contains 1342 data points, and spans latitudes from 70°S to 68°N, representing all major basins. The data may be used to model sea surface iodide concentrations or as a reference for future observations.

scholarly journals Improvement in Modeling of OH and HO2 Radical Concentrations during Toluene and Xylene Oxidation with RACM2 Using MCM/GECKO-A

Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 732
Author(s):  
Victor Lannuque ◽  
Barbara D’Anna ◽  
Florian Couvidat ◽  
Richard Valorso ◽  
Karine Sartelet
Keyword(s):  
Air Quality ◽  
Atmospheric Chemistry ◽  
Oxidation Mechanism ◽  
Chemical Mechanism ◽  
Flow Tube ◽  
Quality Models ◽  
Pollutant Formation ◽  
Master Chemical Mechanism ◽  
Kinetics Of ◽  
Ho2 Radical

Due to their major role in atmospheric chemistry and secondary pollutant formation such as ozone or secondary organic aerosols, an accurate representation of OH and HO2 (HOX) radicals in air quality models is essential. Air quality models use simplified mechanisms to represent atmospheric chemistry and interactions between HOX and organic compounds. In this work, HOX concentrations during the oxidation of toluene and xylene within the Regional Atmospheric Chemistry Mechanism (RACM2) are improved using a deterministic–near-explicit mechanism based on the Master Chemical Mechanism (MCM) and the generator of explicit chemistry and kinetics of organics in the atmosphere (GECKO-A). Flow tube toluene oxidation experiments are first simulated with RACM2 and MCM/GECKO-A. RACM2, which is a simplified mechanism, is then modified to better reproduce the HOX concentration evolution simulated by MCM/GECKO-A. In total, 12 reactions of the oxidation mechanism of toluene and xylene are updated, making OH simulated by RACM2 up to 70% more comparable to the comprehensive MCM/GECKO-A model for chamber oxidation simulations.

scholarly journals Time-resolved emission reductions for atmospheric chemistry modelling in Europe during the COVID-19 lockdowns

2020 ◽  
Author(s):  
Marc Guevara ◽  
Oriol Jorba ◽  
Albert Soret ◽  
Hervé Petetin ◽  
Dene Bowdalo ◽  
...  
Keyword(s):  
Air Quality ◽  
Atmospheric Chemistry ◽  
Emission Reduction ◽  
Power Plants ◽  
Road Traffic ◽  
Urban Background ◽  
Emission Reductions ◽  
Time Resolved ◽  
Wide Range ◽  
Reduction Factors

Abstract. We quantify the reductions in primary emissions due to the COVID-19 lockdowns in Europe. Our estimates are provided in the form of a dataset of reduction factors varying per country and day that will allow modelling and identifying the associated impacts upon air quality. The country- and daily-resolved reduction factors are provided for each of the following source categories: energy industry (power plants), manufacturing industry, road traffic and aviation (landing and take-off cycle). We computed the reduction factors based on open access and near-real time measured activity data from a wide range of information sources. We also trained a machine learning model with meteorological data to derive weather-normalised electricity consumption reductions. The time period covered is from 21 February, when the first European localised lockdown was implemented in the region of Lombardy (Italy), until 26 April 2020. This period includes five weeks (23 March until 26 April) with the most severe and relatively unchanged restrictions upon mobility and socio-economic activities across Europe. The computed reduction factors were combined with the Copernicus Atmosphere Monitoring Service's European emission inventory using adjusted emission temporal profiles in order to derive time-resolved emission reductions per country and pollutant sector. During the most severe lockdown period, we estimate the average emission reductions to be −33 % for NOx, −8 % for NMVOC, −7 % for SOx and −7 % for PM2.5 at the EU-30 level (EU-28 plus Norway and Switzerland). For all pollutants more than 85 % of the total reduction is attributable to road transport, except SOx. The reductions reached −50 % (NOx), −14 % (NMVOC), −12 % (SOx) and −15 % (PM2.5) in countries where the lockdown restrictions were more severe such as Italy, France or Spain. To show the potential for air quality modelling we simulated and evaluated NO2 concentration decreases in rural and urban background regions across Europe (Italy, Spain, France, Germany, United-Kingdom and Sweden). We found the lockdown measures to be responsible for NO2 reductions of up to −58 % at urban background locations (Madrid, Spain) and −44 % at rural background areas (France), with an average contribution of the traffic sector to total reductions of 86 % and 93 %, respectively. A clear improvement of the modelled results was found when considering the emission reduction factors, especially in Madrid, Paris and London where the bias is reduced with more than 90 %. Future updates will include the extension of the COVID-19 lockdown period covered, the addition of other pollutant sectors potentially affected by the restrictions (commercial/residential combustion and shipping) and the evaluation of other air quality pollutants such as O3 and PM2.5. All the emission reduction factors are provided in the supplementary material.

scholarly journals Time-resolved emission reductions for atmospheric chemistry modelling in Europe during the COVID-19 lockdowns

2021 ◽  
Vol 21 (2) ◽  
pp. 773-797
Author(s):  
Marc Guevara ◽  
Oriol Jorba ◽  
Albert Soret ◽  
Hervé Petetin ◽  
Dene Bowdalo ◽  
...  
Keyword(s):  
Air Quality ◽  
Atmospheric Chemistry ◽  
Emission Reduction ◽  
Power Plants ◽  
Road Traffic ◽  
Urban Background ◽  
Emission Reductions ◽  
Time Resolved ◽  
Wide Range ◽  
Reduction Factors

Abstract. We quantify the reductions in primary emissions due to the COVID-19 lockdowns in Europe. Our estimates are provided in the form of a dataset of reduction factors varying per country and day that will allow the modelling and identification of the associated impacts upon air quality. The country- and daily-resolved reduction factors are provided for each of the following source categories: energy industry (power plants), manufacturing industry, road traffic and aviation (landing and take-off cycle). We computed the reduction factors based on open-access and near-real-time measured activity data from a wide range of information sources. We also trained a machine learning model with meteorological data to derive weather-normalized electricity consumption reductions. The time period covered is from 21 February, when the first European localized lockdown was implemented in the region of Lombardy (Italy), until 26 April 2020. This period includes 5 weeks (23 March until 26 April) with the most severe and relatively unchanged restrictions upon mobility and socio-economic activities across Europe. The computed reduction factors were combined with the Copernicus Atmosphere Monitoring Service's European emission inventory using adjusted temporal emission profiles in order to derive time-resolved emission reductions per country and pollutant sector. During the most severe lockdown period, we estimate the average emission reductions to be −33 % for NOx, −8 % for non-methane volatile organic compounds (NMVOCs), −7 % for SOx and −7 % for PM2.5 at the EU-30 level (EU-28 plus Norway and Switzerland). For all pollutants more than 85 % of the total reduction is attributable to road transport, except SOx. The reductions reached −50 % (NOx), −14 % (NMVOCs), −12 % (SOx) and −15 % (PM2.5) in countries where the lockdown restrictions were more severe such as Italy, France or Spain. To show the potential for air quality modelling, we simulated and evaluated NO2 concentration decreases in rural and urban background regions across Europe (Italy, Spain, France, Germany, United-Kingdom and Sweden). We found the lockdown measures to be responsible for NO2 reductions of up to −58 % at urban background locations (Madrid, Spain) and −44 % at rural background areas (France), with an average contribution of the traffic sector to total reductions of 86 % and 93 %, respectively. A clear improvement of the modelled results was found when considering the emission reduction factors, especially in Madrid, Paris and London where the bias is reduced by more than 90 %. Future updates will include the extension of the COVID-19 lockdown period covered, the addition of other pollutant sectors potentially affected by the restrictions (commercial and residential combustion and shipping) and the evaluation of other air quality pollutants such as O3 and PM2.5. All the emission reduction factors are provided in the Supplement.

scholarly journals Evaluation of nitrogen oxides sources and sinks and ozone production in Colombia and surrounding areas

2019 ◽  
Author(s):  
Johannes G. M. Barten ◽  
Laurens N. Ganzeveld ◽  
Auke J. Visser ◽  
Rodrigo Jiménez ◽  
Maarten C. Krol
Keyword(s):  
Air Quality ◽  
Nitrogen Oxides ◽  
Atmospheric Chemistry ◽  
Urban Areas ◽  
Model Comparison ◽  
Anthropogenic Activities ◽  
Remote Sensing Data ◽  
Ozone Production ◽  
Spatial And Temporal Variability ◽  
Baseline State

Abstract. In Colombia, industrialization and a shift towards intensified agriculture have led to increased emissions of air pollutants. However, the baseline state of air quality in Colombia is relatively unknown. In this study we aim to assess the baseline state of air quality in Colombia with a focus on the spatial and temporal variability in emissions and atmospheric burden of nitrogen oxides (NOx = NO + NO2) and evaluate surface NOx, ozone (O3) and carbon monoxide (CO) mixing ratios. We quantify the magnitude and spatial distribution of the four major NOx sources (lightning, anthropogenic activities, soil biogenic emissions and biomass burning), by integrating global NOx emission inventories into the mesoscale meteorology and atmospheric chemistry model WRF-Chem. The comparison with in situ measurements is bound to urban areas whereas the use of remote sensing data allows to also evaluate air quality in remote regions. WRF-Chem was set up for a domain centered over Colombia with a similar resolution as OMI observed NO2 vertical columns as well as the EDGAR anthropogenic emission inventory, both providing information on a ~20 km resolution. However, this apparently poses a challenge regarding comparison with these urban observations. Air mass factors were recalculated based on the vertical distribution of NO2 within WRF-Chem, with respect to the coarse (1° x 1°) a priori profiles. The main reason for recalculation is a more consistent satellite-model comparison but it also reduced the mean bias. WRF-Chem was, on average, able to provide good estimates for tropospheric NO2 columns with an averaged difference of 0.02 x 1015 molecules cm-2, which is

Recycling and Reuse in the Roman Economy

2020 ◽  
Keyword(s):  
Building Materials ◽  
Computational Modelling ◽  
Late Antique ◽  
Roman Economy ◽  
Wide Range ◽  
The Status ◽  
Recent Developments ◽  
Methodological Approaches ◽  
First Time ◽  
Site Types

The recycling and reuse of materials and objects were extensive in the past, but have rarely been embedded into models of the economy; even more rarely has any attempt been made to assess the scale of these practices. Recent developments, including the use of large datasets, computational modelling, and high-resolution analytical chemistry, are increasingly offering the means to reconstruct recycling and reuse, and even to approach the thorny matter of quantification. Growing scholarly interest in the topic has also led to an increasing recognition of these practices from those employing more traditional methodological approaches, which are sometimes coupled with innovative archaeological theory. Thanks to these efforts, it has been possible for the first time in this volume to draw together archaeological case studies on the recycling and reuse of a wide range of materials, from papyri and textiles, to amphorae, metals and glass, building materials and statuary. Recycling and reuse occur at a range of site types, and often in contexts which cross-cut material categories, or move from one object category to another. The volume focuses principally on the Roman Imperial and late antique world, over a broad geographical span ranging from Britain to North Africa and the East Mediterranean. Last, but not least, the volume is unique in focusing upon these activities as a part of the status quo, and not just as a response to crisis.

scholarly journals Bio-Based Alternatives to Phenol and Formaldehyde for the Production of Resins

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2237 ◽  
Author(s):  
P. R. Sarika ◽  
Paul Nancarrow ◽  
Abdulrahman Khansaheb ◽  
Taleb Ibrahim
Keyword(s):  
Raw Materials ◽  
Phenol Formaldehyde ◽  
Raw Material ◽  
Wood Industry ◽  
Suitable Material ◽  
The Past ◽  
Wide Range ◽  
Recent Developments ◽  
Sustainable Materials ◽  
Materials Used

Phenol–formaldehyde (PF) resin continues to dominate the resin industry more than 100 years after its first synthesis. Its versatile properties such as thermal stability, chemical resistance, fire resistance, and dimensional stability make it a suitable material for a wide range of applications. PF resins have been used in the wood industry as adhesives, in paints and coatings, and in the aerospace, construction, and building industries as composites and foams. Currently, petroleum is the key source of raw materials used in manufacturing PF resin. However, increasing environmental pollution and fossil fuel depletion have driven industries to seek sustainable alternatives to petroleum based raw materials. Over the past decade, researchers have replaced phenol and formaldehyde with sustainable materials such as lignin, tannin, cardanol, hydroxymethylfurfural, and glyoxal to produce bio-based PF resin. Several synthesis modifications are currently under investigation towards improving the properties of bio-based phenolic resin. This review discusses recent developments in the synthesis of PF resins, particularly those created from sustainable raw material substitutes, and modifications applied to the synthetic route in order to improve the mechanical properties.

Recent Developments in Computational Methods for the Analysis of Ducted Propellers in Open Water

2019 ◽  
Vol 63 (4) ◽  
pp. 219-234
Author(s):  
João Baltazar ◽  
José A. C. Falcão de Campos ◽  
Johan Bosschers ◽  
Douwe Rijpkema
Keyword(s):  
Computational Methods ◽  
Open Water ◽  
Boundary Element Methods ◽  
Navier Stokes ◽  
Hydrodynamic Analysis ◽  
Numerical Predictions ◽  
Ducted Propeller ◽  
Recent Developments ◽  
Propeller Performance ◽  
Ducted Propellers

This article presents an overview of the recent developments at Instituto Superior Técnico and Maritime Research Institute Netherlands in applying computational methods for the hydrodynamic analysis of ducted propellers. The developments focus on the propeller performance prediction in open water conditions using boundary element methods and Reynolds-averaged Navier-Stokes solvers. The article starts with an estimation of the numerical errors involved in both methods. Then, the different viscous mechanisms involved in the ducted propeller flow are discussed and numerical procedures for the potential flow solution proposed. Finally, the numerical predictions are compared with experimental measurements.

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