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Integrated GISIntegrated GIS--based based

ExperimentalExperimental--Computational Computational

Methods for Urban Air PollutionMethods for Urban Air Pollution

Faculty of Environment

Methods for Urban Air Pollution Methods for Urban Air Pollution

ModelingModelingAmir M. Yadghar

24 Dec. 2008

PhD Candidate

University of Western Ontario

Air Pollution Air Pollution Definition

از اعم آالينده نوع هر وجود از ستا عبارت هوا يآلودگكيفيتكهيزمانمدتدرومقدار به هوا در گاز و مايع ،جامد ييزروربورزويعج ي به يا و اندازد خطر به جانداران ديگر و انسان يبرا را يزندگ.آورد وارد خسارت ،اموال و يباستان آثار

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مدل آلودگي هوا چرا؟–مدلسازي آلودگي هواها برآورد انتشار آالينده) 1

چرا؟–مدلسازي آلودگي هواارزيابي استراتژي هاي كنترلي جايگزين) 3صحيح منابع شناسايي) 2

چرا؟–مدلسازي آلودگي هواتخمين اثرات مضر بر سالمتي) 5نظارت مؤثر) 4

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چگونه؟–مدلسازي كيفيت هوا

محدوده هاي الزم براي مدل سازي

فاكتورهاي مشترك در مدل ها

1. Empirical Equations (US EPA, ASHRAE)

2. Physical models (water flume, wind tunnel, etc.)

مدلسازي

3. Computational Fluid Dynamics (CFD)

Numerical (computer) models:

1. Gaussian models (ISC3, AERMOD, SCREEN3)

2. Puff models (CALPUFF)

هاي كيفيت هوا مدلDispersion Modeling - These models are typically used in the permittingprocess to estimate the concentration of pollutants at specified ground-levelreceptors surrounding an emissions source.

Photochemical Modeling - These models are typically used in regulatory orpolicy assessments to simulate the impacts from all sources by estimatingpollutant concentrations and deposition of both inert and chemically reactivepollutants over large spatial scales.

Receptor Modeling - These models are observational techniques which usethe chemical and physical characteristics of gases and particles measured atsource and receptor to both identify the presence of and to quantify sourcecontributions to receptor concentrations.

Experimental Methods

Different kinds

Different fields

Why?

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فيزيكيمدلسازي تونل بادA wind tunnel is a research tool developed to assist

with studying the effects of air moving over or

around solid objects.

اليه مرزي–تونل باد

Atmospheric Boundary Layer (ABL)

كاربرد–تونل باد

Pedestrian-level Wind Environment

Wind Climate studies

Snow and Ice studies

Indoor Air Quality studies

Simulation of Downburst

Atmospheric dispersion of gaseous pollutants in complex terrain

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GPS Dropwindsondeدستگاه Computational Fluid Dynamics (CFD) is one of the

branches of fluid mechanics that uses numerical methods

and algorithms to solve and analyze problems that involve

fluid flows Computers are used to perform the millions of

CFD

fluid flows. Computers are used to perform the millions of

calculations required to simulate the interaction of fluids and

gases with the complex surfaces used in engineering. Even

with simplified equations and high-speed supercomputers,

only approximate solutions can be achieved in many cases.

Ongoing research, however, may yield software that improves

the accuracy and speed of complex simulation scenarios such

as transonic or turbulent flows.

CFD

The tests and modelings demonstrate the possibilities of CFD

techniques in solving a broad range of air pollution problems. The

CFD techniques are rather complex, but capable of handling

situations where due to complex geometry, thermal effects or flow

conditions other simpler methods fail.

CFD Methods Consideration

• Topography and complex geometry: choose of the co-ordinate

system and computer grid;

• Turbulence closure for air pollution modelling: modified k-ε modelg

for stable stratified ABL;

• Boundary conditions for vertical profiles of velocity for stable-

stratified atmosphere;

• Effects of the radiation and thermal budget of inclined surfaces to

dispersion of pollutants;

• Artificial sources of air dynamics and circulation

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Navier-Stokes: معادله حاكم CFD Modeling

FLUENT

CFDنمونه اي از مدلسازي با Wind Tunnel Tests

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Wind Tunnel Tests Wind Tunnel Tests

Wind Tunnel Tests Eulerian Advection/Diffusion Models

Wind speeds and concentrations are specified in a

stationary co-ordinate system (i.e. as “fields”)y y ( )

Wind speed field is found using computational fluid

dynamics (CFD)

Advection diffusion equation solved for concentration

field.

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Geographical Information System

نرم افزار، سخت از اي يافته سازمان ي مجموعه جغرافيايي، اطالعات سيستم جهت كه است متخصص انساني نيروي و روش جغرافيايي، اطالعات افزار، تلفيق و تحليل پردازش، سازي، هنگام به ذخيره، سازماندهي، ورود،كسب،

و ذخيره بر عالوه جغرافيايي اطالعات سيستم اين بنابر .شود مي ايجاد اطالعات به و سريع بازيابي امكانات و رقومي شكل به جغرافيايي اطالعات سازماندهي

ها، پردازش انواع براي را الزم قابليتهاي و ابزار اطالعات، سازي هنگام.سازد مي فراهم جغرافيايي اطالعات سازي مدل و تلفيق فضايي، هاي تحليل

GISGIS

Traffic Demand&

Road Network

Driving cycles&

Fleet composition

Meteorological&

Climatic Data

GIS STRUCTURE FOR AIR POLLUTION MODELLING

GEOGRAPHIC INFORMATION SYSTEM

Traffic Model

Emission Model

Dispersion Model

Traffic Flows Mapping

Emissions Mapping

Concentrations Mapping

Topography Traffic Routes Data Layer

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Urban Blocks Land Use GIS Model 1 – Example 2

CO – Cell Modeling CO (LDV) – Buffer Modeling

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CO – Ordinary Kriging Model

ل ل Aت l i

نتايج

Analysingتحليل

Verifyingبررسي

Integration between computational methods,

پيشنهادهايي براي آينده

experiments and numerical methods in

environmental modeling especially air pollution

modeling, is an area in its infancy.

از توجه شما متشكرم