What are the emissions from aircraft?

The exhaust fumes from jet and turbopropeller aircraft contain the same substances as emissions from other engines. These include, for example, carbon dioxide (CO2), nitrogen oxides (NOx), unburned hydrocarbons (HC), carbon monoxide (CO), water vapour, sulphur oxides (SOx) and particles.

Aviation petrol, i.e. kerosene, is used as the fuel in turbine engines. The amount of carbon dioxide and water vapour created in the combustion of fuel is directly proportional to the amount of fuel. In the combustion process, one kilogramme of kerosene yields 3.2 kg of carbon dioxide and 1.3 kg of water vapour. The amount of other emissions varies at different stages of the flight, and are also affected by such factors as the type of aircraft and engines and the take-off weight of the plane.

The amount of emissions from air traffic

Carbon dioxide emissions from air traffic can be compared, for example, to the amount of emissions that are currently included in the EU’s emissions trading scheme (air traffic is not currently included). The EU’s emissions trading involves around 12,000 fixed installations that produce around 2,200 million tonnes of CO2 emissions per year. Emissions from all internal European flights, including domestic flights within member countries, totals 52 million tonnes, i.e. approximately 2.4% of the emissions included in emissions trading. The emissions from all aircraft departing and arriving in the EU and overflying the EU area totals 162 million tonnes, which is around 7.4% of the emissions included in emissions trading. The information is from a report commissioned by the EU Commission, which is available via the following Links.

The total CO2 emissions from the entire Finnish economy in 2003 were 86 million tonnes. CO2 emissions from domestic air traffic amount to around 0.3 million tonnes per year. The emissions from all flights departing and arriving in Finland, excluding overflights, total approximately 2 million tonnes, i.e. roughly one per cent of the emissions of flights from the current EU-25.

Energy efficiency of aircraft

The consumption of fuel by aircraft per seat has decreased by around 70 per cent over the last 40 years.

The current rule of thumb on fuel consumption is that an intercontinental flight consumes fuel in the region of 3 litres/passenger/100 km, if the plane is full. On shorter flights, a jet passenger plane consumes fuel in the region of 3–5 litres/passenger/100 km, if the plane is full.

For example, a return flight with a full plane from Helsinki to the Canary Islands consumes in the region of 200 kg of fuel per passenger, i.e. around 250 litres. Similarly, a return flight from Helsinki to Ivalo consumes in the regions of 80 kg of fuel per passenger, i.e. around 100 litres. If the plane is not full, the consumption of fuel per passenger is naturally greater.
 

Emissions from individual flights

 
The International Civil Aviation Organization (ICAO) has developed a methodology to calculate the carbon dioxide emissions from air travel. The emission calculator can be found here. Some airlines have also created similar type of calculatiors on their websites. Typically the results from different calculators are slightly different due to the type of the backround data.

Emission trends

It has been forecast that emissions from air traffic will increase. The consultation report of the EU used general estimates, according to which emissions from air traffic would increase 4 per cent per year up to 2012. The estimate mainly concerns Europe.

Air traffic in the US is increasing more slowly than in Europe. The most rapid growth in air traffic is in the Far East.