A SURVEY OF AIR QUALITY DISPERSION MODELS FOR PROJECT LEVEL CONFORMITY ANALYSIS (original) (raw)
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Sensitivity Analysis of CALINE4 and ISCST3 -Air Pollutant Dispersion Models
The present paper is focused on the sensitivity analysis of California line source model 4 (CALINE4) and Industrial source complex short-term model 3 (ISCST3) by changing one input variable at a time while keeping other variables as constant to identify the effect of each input variable on predicted PM 10 and NOx concentrations. State Highway (SH-17) length of 3.3 km passing through the industrial area of Mysuru with six receptor points has been considered in the present study. The sensitivity analysis of CALINE4 and ISCST3 model showed pollutant concentrations were more influenced by meteorological factors such as wind speed, wind direction, atmospheric stability conditions; source strength such as traffic volume, emission factors (WEF) and pollutants emission rates. However, it was also found that pollutant concentrations were less influenced by mixing height, road width, and surface roughness coefficient.
The California Department of Transportation (Caltrans), the California Air Resources Board (ARB), and the University of California, Davis have worked over the past three years to improve mobile source emissions inventory modeling. The research is motivated by two historical problems that exist in California, that of estimating facility-specific (e.g., freeway) emissions using tools developed to represent emissions from entire trips, and that of determining conformity by comparing air agency emissions budgets created with one model (BURDEN) to transportation agency emissions estimates created with a separate model (DTIM). This paper reports on the work scope, progress to date, and status of the new modeling tools. Future papers will describe specific elements of the program in more detail. One of the project's major accomplishments to date includes the collection of over 260 hours of target-vehicle driving behavior data. Data were collected in large metropolitan areas (Los Angeles, San Francisco), a medium-sized area (Sacramento), and more rural communities (San Joaquin Valley). In comparison, mobile source emissions modeling tools currently used in California include emission factors based on 15 hours of target-vehicle driving data collected in Los Angeles during 1992 ("LA92" data set). The CAMP project expands the fundamental data available to evaluate driving behavior and construct mobile source emissions factors, a contribution with national implications.
Ambient Air Quality (AAQ) has been monitored over a period of 8 months from November, 2016 to June, 2017, considering winter, summer and monsoon seasons at three identified locations along the highway passing through industrial area of Mysuru city, India. The number of 2W vehicles were found to be maximum (13620 nos./d) followed by 4W (4654 nos./d), HDV (2410 nos./d) and LDV (2024 nos./d). During weekdays the peak traffic volumes were observed at 08:00–10:00 hours and 17:00–20:00 hours. All the monitored pollutant concentrations were found to be well within National Ambient Air Quality Standard (NAAQS) in all the seasons, except during winter season PM 10 and PM 2.5 at receptor R1 were found to be exceeding the NAAQS. The comparison between observed values with Industrial source complex short term model 3 (ISCST3) and California line source model 4 (CALINE4) predictions showed ISCST3 model prediction found to be good agreement with observed NOx and SO 2 concentration, however, CALINE4 model prediction was good agreement with observed PM 10 concentration. It was also observed that, NOx and PM 10 was contributing ~86% and ~68% from line sources and ~14% and ~32% from point sources, respectively, however, SO 2 was contributing ~67% from point sources and ~33% from line sources. The statistical analysis of ISCST3 model was found to be within the acceptable values, indicating a good agreement with the observed pollutant concentrations.
Application of CALINE4 for Modeling Dispersion of Roadside Co and NO2 Emissions in Szeged, Hungary
REZUMAT. În această lucrare este prezentat un studiu al calităţii aerului din regiunea Szeged, pentru o perioadă cuprinsă între 1995 şi 2007. Parametrii utilizaţi sunt după cum urmează: cei meteorologici, caracteristicile drumului şi poziţii ale receptorilor. Efectele calităţii aerului de la emisiile de trafic au fost evaluate folosind un model de dispersie-CALINE4. Cuvinte cheie: calitatea aerului, model de dispersie, CALINE4.
Methodology for Evaluating Highway Air Pollution Dispersion Models
NCHRP Report, 1981
This report describes the development and application of a comprehensive methodology for assessing the performance of dispersion models used to estimate highway-related air pollution. Specifically, the goals of the study were to: Develop methods for evaluating the performance of highway air-pollution dispersion models; Assembel and document a data base to be used to assess model performance; and Demonstrate the application of the model evaluation procedure by performing a preliminary evalaution of selected models. The report is organized into seven chapters and seven technical appendixes that include mathematical derivations and user's guides to the software and data base. The findings of the study are discussed in Chapters Two through Four. Chapter Two describes the development of the statistical methodology. Sensitivity analysis is discussed in data base. The application of the methodology is described in Chapter Five. Conclusions and recommendations are given in Chapter Six. ...
1976
At the request of the Washington State Department of Highways a study was conducted to evaluate three computer models specifically designed to predict carbon monoxide (CO) concentration at receptor points along roadways. The models were evaluated on their ability to predict values obtained from a monitoring network established along various roadways in the State of Washington. Monitoring consisted of 12 ground level CO stations, 2 meteorological stations and traffic counters. Traffic speeds were sampled for conformity during peak hours. The final selected models, CALINE II and EPA's HIWAY, were given calibration factors to be used when calculating Receptor Concentrations for Impact Assessments.
A comparison of three highway line source dispersion models
Atmospheric Environment (1967), 1978
paper compares three idealized line source dispersion models that predict carbon monoxide concentrations near highways. The models are EPA HIWAY , the original California Line Source CALINE2 (Ward, 1975). The comparison includes a sensitivity analysis and model validation. A sensitivity analysis refers to an analysis of the dependence of normalized concentration to variations of several independent input parameters. Model validation is accomplished by comparing measured carbon monoxide concentrations with concentrations predicted by the models. The sensitivity analysis indicates that the EPA HIWAY model predicts higher pollutant concentrations than the two California models for oblique and crosswind cases. For parallel wind conditions, the California Line Source model predicts higher pollutant concentrations. A comparison of predicted and measured concentrations shows that all of the models overestimate concentrations for parallel wind conditions and underestimate concentrations for oblique and crosswind conditions.
atmosphere, 2021
Transportation sources are a major contributor to air pollution in urban areas, and the role of air quality modeling is vital in the formulation of air pollution control and management strategies. Many models have appeared in the literature to estimate near-field ground level concentrations from mobile sources moving on a highway. However, current models do not account explicitly for the effect of wind shear (magnitude) near the ground while computing the ground level concentrations near highways from mobile sources. This study presents an analytical model (SLINE 1.0) based on the solution of the convective–diffusion equation by incorporating the wind shear near the ground for gaseous pollutants. The dispersion coefficients for stable and unstable atmospheric conditions are based on the near-field parameterization. Initial vertical dispersion coefficient due to the wake effect of mobile sources is incorporated based on a literature review. The model inputs include emission factor, wind speed, wind direction, turbulence parameters, and terrain features. The model is evaluated based on the Idaho Falls field study (2008). The performance of the model is evaluated using several statistical parameters. Results indicate that the model performs well against this dataset in predicting concentrations under both the stable and unstable atmospheric conditions. The sensitivity of the model to compute ground-level concentrations for different inputs is presented for three different downwind distances. In general, the model shows Type III sensitivity (i.e., the errors in the input will show a corresponding change in the computed ground level concentrations) for most of the input variables using the ASTM (American Society for Testing and Materials) method. However, some recalibration of the model constants is needed using several field datasets to make sure that the model is acceptable for computing ground-level concentrations in engineering applications.
Development of an emission model for
1994
This paper describes an emission model, developed at the National Autonomous University of Mexico (UN AM) to feed a CO-dispersion model for Mexico City. At this moment, the emission model generates hourly vehicular CO-emissions in the valley of Mexico, taking into account vehicular composition and volume, mean velocity, traffic fluxes and their hourly changes. A distinction is made between primary and secondary roads. Fixed emissions are not taken into account at the moment.