This paper summarises the management and procedural issues that led to the successful development of AERMOD and CALPUFF and how they will come to be approved regulatory models by the US-EPA in the next few months. The legal requirements for constantly updating models is contained in the 1977 Clean Air Act that requires the US-EPA to publish a "Modelling Guideline" and to hold a hearing ...
A local air quality management system, and the use of dispersion modelling as a tool for the system, are described. The Turkish town of Gehze is used as a model.Keywords: air pollution, air quality management, dispersion modelling, ...
An urban dispersion model (ADMS?Urban) was run to calculate PM10 and NO2 concentration during a one-year period, on a district of Bologna, Italy. Moreover, the exposure of 333 children was estimated using model outputs corrected with observations. The model was able to correctly simulate the long-term statistical properties of roadside observed concentrations (such as annual mean and frequency ...
As an air pollutant is transported, the pollutant disperses into the surrounding air so that it arrives at a lower concentration than it was on leaving the source. Strict environmental regulations worldwide resulted in a growing concern about the validity of air quality dispersion models. The present work is a try to evaluate the applicability of some dispersion models on the emission from an ...
This paper describes some modifications to a mesoscale model surface scheme to better account for urban heat–storage. The approach involves integrating the Subgrid Town Energy Budget (STEB) with the Regional Atmospheric Modelling System (RAMS). The integrated system has been applied to the investigation of the Urban Heat Island (UHI) of Rome, Italy, and the surrounding area (Lazio Region), ...
This study describes in brief the latest extensions of the Danish Geographic Information System (GIS)–based air pollution and human exposure modelling system (AirGIS), which has been developed in Denmark since 2001 and gives results of an evaluation with measured air pollution data. The system shows, in general, a good performance for both long–term averages (annual and monthly averages), ...
The concentration fluctuations of a dispersing hazardous gaseous pollutant in the atmospheric boundary layer, and the hazard associated with short–term concentration levels, demonstrate the necessity of estimating the magnitude of these fluctuations using predicting models. To predict and estimate the maximum expected dosage and the exposure time within which the dosage exceeds certain health ...
Wind tunnel measurements over a regular array of cubes were carried out to investigate the influence of surface inhomogeneities on the development of the urban boundary layer. Two idealised cases were investigated. The first one was in terms of a strong step change in roughness from very smooth to very rough with a low turbulent approach flow and a thin approach boundary layer. For this case it ...
A Gaussian atmospheric dispersion model, Industrial Source Complex Short Term (ISCST3), was used to estimate ground-level concentrations of sulphur dioxide (SO2) emitted from source categories of industrial and domestic heating in the city of Izmir, Turkey. Predictions were estimated for the year 2000 across a study area of 80 km x 100 km. Statistical analyses were carried out to evaluate the ...
Air quality modelling near airports has received attention due to the impact of emissions from aircrafts near ground level. This work is part of the model inter-comparison study undertaken for the Department of Transport in connection with air quality near Heathrow Airport. Results formed part of a submission to the UK government in July 2006. The Emissions and Dispersion Modelling System (EDMS) ...
Parameters related with natural and traffic producing turbulences are estimated for four street canyons considering all wind directions. Available data include air pollution concentrations measured in Göttinger Strasse (Hannover, Germany), Schildhornstrasse (Berlin, Germany), Jagtvej (Copenhagen, Denmark) and Hornsgatan (Stockholm, Sweden), background pollution, wind speed and direction measured ...
Canarina DISPER Software · air quality dispersion model Symbol / Definition Ly= Initial plume length for Schulman-Scire downwash sources with enhanced lateral plume spread (m) Lb= Lesser of the building height and crosswind projected building width (m) _= Alongwind length of open pit source (m) P(x,y)= Profile adjustment factor (dimensionless) p= Wind speed power law profile ...
We observed the turbulence and vertical profile of temperature in and above the roughness sublayer (RS) using a tower, a tethered balloon and a Doppler sodar in Himeji City. A 3–D ultrasonic anemometer–thermometer was sited at a height of 54 m on the tower. The present results showed that in the RS, the ratio of friction velocity to wind speed, u* /u, observed under unstable conditions of −4.2 ...
In the more than 200 air quality modeling analyses that ALL4 meteorologists have conducted, demonstrating compliance with the annual nitrogen dioxide (NO2) National Ambient Air Quality Standard (NAAQS) of 53 parts per billion (ppbv) has rarely been an issue. The relative ease for demonstrating compliance with the annual NO2 NAAQS is due to two (2) factors. First, the NAAQS for NO2 is an annual ...
This research establishes an approach to modelling a congested road network for air quality management, which enables the assessment of traffic management solutions that may create only subtle changes in the traffic flow regimes. Road network emissions have been calculated using standard factors taking into account details of vehicle fleet composition, average speeds and road type. Additionally, ...
The main goal of this study was to predict the airflow in a street canyon surrounded by an urban area using CFD modelling. In the street geometry described in the main part, the actual airflow directly influences air infiltration into buildings. Different models of turbulence were tested as well as specific wind boundary conditions. A correct assignment of boundary conditions (i.e., mainly wind ...
The Mixing Height (MH) is one of the most important parameters that characterise the range of the atmospheric turbulence. This parameter shows characteristic diurnal variation but cannot be measured immediately. Therefore, it is evaluated indirectly by measuring other quantities. The measurement of radon concentration in the atmospheric air is one of the methods using natural occurring ...
The simulations of hourly 222Rn concentrations are performed with the EMEP model to validate different parameterization schemes for vertical mixing. In addition to recently evaluated non–local vertical diffusion schemes, a new scheme which is a local and based on total turbulent energy (TTE) has been implemented in the model and evaluated. Due to its properties 222Rn is commonly used to ...
Most modern cities practically consist of street canyons, making monitoring of the level of their pollution an important issue. In this study, a Computational Fluid Dynamics (CFD) simulation of pollutant dispersion was performed for a real, complex-geometry street canyon for various wind directions and speeds. Typical street-canyon effects – like the formation of a longitudinal vortex for wind ...
During the development phase of an air quality dispersion model and in subsequent upgrades, model performance is constantly evaluated. These evaluations generally compare simulation results using simple methods that do not account for the fact that models only predict a portion of the variability seen in the observations. To fill a part of this void, the US Environmental Protection Agency (EPA) ...