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Emission inventory of air pollutants in Tehran
Air pollutants are emitted into the atmosphere from stationary, area and mobile sources. Stationary sources include utility, industrial, institutional and commercial facilities.
Examples are electric power plants, oil – gas refineries, phosphate processing plants, pulp and paper mills, and municipal waste combustors. Area sources include many individually small activities such as gasoline service stations, small paint shops, consumer solvent use, open burning associated with agriculture, etc. Mobile sources, especially from on-road vehicular traffic, constitute a major source of air pollution in towns and cities.
In the current study, pollutant emissions are estimated for the year 2005 for CO, PM10, PM2.5, NOx, SOx, and NMVOC which are emitted from point, area and mobile sources in the Greater Tehran Area (GTA).
According to a recent estimate, there are more than 2 million vehicles and some 300 thousand industrial factories and offices in Tehran. Although there are few inventories of pollution sources available in Tehran, those available suggest that concentration of CO, NO, NO2, SO2, O3 and suspended particulate matter (SPM) in the GTA are well beyond the World Health Organization (WHO) standard. Particularly, the CO concentration often exceeded the 80 ppm limit.
While a variety of sources contribute to air pollutants, it is estimated that mobile source emissions account for almost 85% of the air pollution in the GTA and are particularly important, since these emissions occur in the vicinity of the city population. Accordingly, new standards for mobile sources have been enacted to address this problem.
Mobile Source Emissions Inventory survey
Mobile sources mainly consist of on-road motor vehicles and other mobile sources include boats and ships, trains, aircraft and off-road equipments (garden, farm and construction).
Key literature analysis of studies (Cooper, 1989; Beaton et al., 1992; Bose, 1996; Cernuschi et al., 1995; Derwent et al., 1995; Joumard et al., 1995; Lawson et al., 1990; Mitsoulis et al., 1994; Onursal and Gautam, 1997; Riveros et al., 1995; Stein and Toselli, 1996; Sturm et al., 1997) relating to traffic pollution in urban centers indicate that studies concerning detailed impact of vehicle emissions on the ambient air quality are few outside north America and Europe. This is due to the complexity of organizing and integrating information on:
-emission of pollutants to the atmosphere from a dynamic EDB (Emission DataBase),
– meteorological conditions,
-processes affecting pollutant concentrations spatially at differnt location and time.
On-Road Motor Vehicles
On-road motor vehicles consist of passenger cars, trucks, buses, motorcycles, etc. Emissions from on-road motor vehicles are a major portion of the emission inventory and are estimated by using available vehicles and traffic data bases and related emission factors. Vehicle emissions are directly related to the variations in the traffic flow pattern, which vary in location and time. The characterization of the temporal variability of emissions is difficult because it requires an accurate dynamic EDB.
Emission standards
An emission performance standard is an upper limit that should not be exceeded by emissions from a regulated source. To that end, different types of emission control technologies have been implemented on vehicles. Evaluations of vehicular emissions are conducted using a special driving cycle to simulate road driving on a dynamometer chassis, and by measuring their air pollutants emissions. Dynamometer is tuned in a way that braking power is compatible with striking the barriers as it is on actual roads and using the real vehicle weight.
Table of contents :
Abstract
Acknowledgements
Table of contents
Chapter 1: Introduction
1.1 Scale and the urban surface
1.2 The urban boundary layer
1.3 Urban canopy parameterization in MMMs
1.4 Urban air quality
1.5 Overview of Tehran characteristics
1.6 Thesis outline
References
Chapter 2: Development and Evaluation of a High Resolution Emission Inventory for Air Pollutants and Heat Generation
2.1 Introduction
2.2 Emission inventory of air pollutants in Tehran
2.2.1 Mobile Source Emissions Inventory survey
2.2.1.1 On-Road Motor Vehicles
2.2.1.1.1 Emission standards
2.2.1.1.2 Vehicles and traffic data base
2.2.1.1.2.1 Categories and subcategories of vehicles
2.2.1.1.2.2 Traffic data
2.2.1.1.3 Emission factors
2.2.1.1.4 On-Road emissions
2.2.1.2 Railway emissions inventory
2.2.1.3 Aircraft emission inventory
2.2.2 Stationary emissions inventory survey
2.2.3 Results and discussion
2.3 Emission inventory of anthropogenic heating in Tehran
2.3.1 Overview
2.3.2 Calculation methodology
2.3.2.1. Heating from vehicular traffic
2.3.2.2. Heating from electricity consumption
2.3.2.3. Heating from fuels consumption
2.3.2.4. Heating from human metabolism
2.3.3 Results and discussion
References
Chapter 3: Local Meteorology and Urbanization Effects
3.1 Introduction
3.1.1 Topography of the region
3.1.2 Main features of the climate and meteorology in the region
3.2 Model and methods
3.2.1 MM5 GSPBL scheme modifications
3.2.1.1 Momentum equation
3.2.1.2 Thermal equation
3.2.1.3 Humidity equation
3.2.1.4 Turbulent kinetic energy equation
3.2.1.5 Turbulent length scale (TLS)
3.2.2 Description of the SM2-U(3D) Model
3.2.2.1 Mean heat flux inside the canopy
3.2.2.2 Net radiation flux
3.2.2.3 Latent heat flux from paved surfaces
3.2.2.4 Sensible and net radiative fluxes
3.3 Model configuration
3.4 Case study simulations and results
3.4.1 Synoptic condition during episode
3.4.2 Numerical experiments and observation data
3.4.2.1 Analyses of the Vertical Profiles inside the PBL
3.4.2.2 Surface Meteorological Fields
3.4.2.3 Meteorological Fields within and above the Canopies
3.4.2.3.1 Within the canopy
3.4.2.3.2 Above the canopy
3.4.2.4 Analyses of the PBL height
3.4.2.5 Analyses of local circulations
3.5 Conclusions
References
Chapter 4: Sensitivity and improvements of Tehran air quality calculations using different meteorological inputs
4.1 Introduction
4.2 Model and methods
4.3 Case study simulations and results
4.4 Conclusions
References
Chapter 5: Conclusions and Perspectives
