Advanced Emission Model (AEM)
The Advanced Emission Model (AEM) is a standalone application, developed and maintained by the EUROCONTROL Experimental Centre.
It can estimate:
- the mass of fuel burned by the main engines of a specified type of aircraft with a specified type of engine flying a specified 4D trajectory;
- the corresponding masses of certain gaseous and particulate emissions which are produced by the burning of that fuel. The gases whose masses can be estimated include CO2, H2O, the oxides of nitrogen (NOx) and sulphur (SOx), unburnt hydrocarbons (HC), CO, benzene and some other volatile organic compounds (VOCs) and gases (TOGs).
Below 3,000 feet, the fuel burn calculation is based on the landing and take‑off (LTO) cycle defined by the ICAO Engine Certification specifications. The ICAO LTO cycle covers four modes of engine operation. They are used in AEM to model the following six phases of operation: taxi-out, taxi-in (idle), take-off, climb-out, approach and landing (approach). The ICAO Aircraft Engine Emissions Databank (AEED) for turbofan and turbojet engines, combined with the FOCA databank for pistons (and potentially FOI for turboprops), provides emission indices and fuel flow for a very large number of aircraft engines. The AEM links each aircraft appearing in the input traffic sample to one of the engines in the AEED.
Above 3,000 feet, during the climb, cruise, descent (CCD) phases of flight, the fuel burn calculation is based on EUROCONTROL’s Aircraft Database (BADA). Emission calculations are based on the AEED, but emission factors and fuel flow are adapted to the atmospheric conditions at altitude by using a method initially developed by Boeing (The Boeing Fuel Flow Method 2 – BFFM2). BFFM2 makes it possible to estimate emissions for the NOX, HC, and CO pollutants.
The emissions for the H2O and CO2 pollutants are a direct result of the oxidation process of the carbon and hydrogen contained in the fuel with the oxygen contained in the atmosphere. The SOX emissions depend directly on the sulphur content of the fuel used. All three are directly proportional to the amount of fuel burned. Benzene emissions, as well as VOC, TOG and all pollutants derived from VOC-TOG, are proportional to the HC emissions. Particulate matter (PM) emissions result from the incomplete combustion of fuel.