The King's modelling team has a wealth of experience in developing emissions inventories that can provide the answers to complex air pollution problems.
The London Atmospheric Emissions Inventory (LAEI) is an excellent example of the application of one such inventory.
- Emissions of NOX, NO2, CO, VOC, PM10 exhaust, PM2.5 exhaust, PM10,2.5 break wear, PM10,2.5 tyre wear, PM10,2.5 resuspension and CO2, between 1995 and 2035.
- The LAEI provides an emissions inventory that reflects the geography of the roads in London. This enables the accurate assessment of population exposure and health impacts as well as providing compatibility with other map products commonly used within GIS systems.
- Vehicle speed and vehicle flow are provided separately on each road link using GPS based vehicle speed.
- Detailed treatment of traffic flow using trend smoothing techniques and generalise additive models.
- The LAEI is the first inventory to make predictions of primary NO2 emissions and is developing measurement based corrections for uncertainty non-exhaust PM emissions such as those for brake, and tyre wear and resuspension.
- Advanced data use such as automatic number plate recognition data to enhance vehicle stock information.
- Incorporation of iBus trip information and vehicle stock for a highly detailed route based emissions estimate for these vehicles.
- Upwards of 400 vehicle types in the model, including hybrid and retrofit technologies.
- Use of a multitude of alternative emissions factors, from UK/European COPERT factors to Swiss/German handbook factors and King’s own roadside measurement based emission factors (RSD).
Road Traffic emissions for Great Britain
Many of the LAEI emissions methods have been used in the creation of a Great Britain emissions inventory for road traffic. The model is based upon DfT’s manual count/trip start/vehicle km data and calculates individual link and 1x1 km2 emissions totals for Great Britain for all LAEI pollutants between 1995 and 2035.
A complete description of the GB emissions inventory is given in:
Trends in NOX and NO2 emissions from road traffic in Great Britain
The modelling team calculate Heathrow and London City Airport emissions for the LAEI.
Aircraft emissions are produced by combining: emission factors and fuel flow rates from the ICAO databank, LTO (Landing and Takeoff) cycles composed of several phases, detailed aircraft data from the Civil Aviation Authority (CAA) including registration number, flight date and time, runway identifier (arrival or departure), stand number and the total plane movements disaggregated by plane and engine type.
It accounts for the effect of ambient conditions, the forward speed emissions effect, aircraft brake and tyre wear, a method to estimate total start-up emissions, aircraft refuelling and APU emissions.
The LAEI also includes emissions from non aircraft sources such as airside vehicles, engine testing, heating plant, staff car parks and fire training. This is consistent with the PSDH (Project for the Sustainable Development at Heathrow) and with the air quality work undertaken for the British Airports Authority (BAA).
The modelling team has also developed a new passenger shipping methodology for the LAEI 2010, a source not included in previous iterations of the LAEI.
Emissions from passenger shipping were calculated using spatially disaggregated and vessel specific fuel consumption data - developed by combining annual fuel consumption data with timetabled movements and engine specifications.