AirWare On-line Manuals: Emission factors combustion

AirWare On-line Reference Manual

Release Level	5.3.0 beta
Release Date	2007 06
Revision Level	1.1

Emission factors

Emissions for combustion related sources are taken by the models from the emission data base; these values are either directly entered with the respective soucre, or can be estimates from source specififc data on

fuel type
annual fuel consumption

together with the temporal emisison patterns

The Emission factors are stored in the data base (DATA BASE: XX; TABLE: XDX)

DATA BASE DESCRIPTION

The set of fuel types the system uses and offers as choices for editing with each emission source is defined as a set of values for a Descriptor fuel_type in the Knowledge Base; the user can add or delete fuel types as required;

The set of pollutants considered is driven by the descriptor emission_pollutant,
and can be changed in the Knowledgebase. The current deafult set includes:

CO, CO2, NO, NOx, NO2, PM10, PM2.5, VOC.

Database:       AIR
Table:             EMISSION_FACTOR
                                                                                                                                    
Structure:
ID            int(10) unsigned
DESCRIPTOR    varchar(64)
VALUE         varchar(255)
primary key   (ID, DESCRIPTOR)
                                                                                                                                    
Valid descriptor/ value pairs are:
                                                                                                                                    
LOCATIONID=53
NAME=Text
OWNER=Text (=username)
DESCRIPTION=Text

Combustion:  CLASSID=82
em_factor_type=combustion
Factors are stored as 'pollutant + _emission_factor_ +  fuel_type'
eg.: NO2_emission_factor_coal

The calculation strategy

The basic emission estimates are implemented as follows: the emission factor defines the amount of pollutant generated (in g) from burning one kilo of fuel. This is then converted to the required emission unit of g/s by correcting for the number of seconds in a year and the annual fuel consuption data values.

The emission inventory primarily uses direct emission estimtes; If and only IF no direct emission estimate is in the data base (for any or all of the pollutants), the estimation is attempted IF and only IF fuel type and annual fuel consumption are both defined. Then, whenever the emission inventory ir recalculated (the button: RECALCULATE) is pressed) missing, undefined emission values will be replaced with the value estimated from fuel type, consumption, and the emission factor if defined in the data base. derived estimates wherever possible.

Emission factor editing

The emission factor can directly be edited in the data base (DATA BASE: XX; TABLE: XXX). An interactive editor with rule-based assistance and analytical functions are under development.