Aircraft movements in the landing and take-off phases, airport activities, infrastructures and surrounding road traffic affect air quality. The substances emitted are primarily carbon dioxide (CO2), nitrogen oxides (NOx), carbon monoxide (CO), volatile organic compounds (VOC) and fine particles. The air protection ordinance (OPair) specifies a maximum emission value for some pollutants.

Since 1996, the EOLE station has been measuring air quality on the runway edge at the position where jet engine thrust is greatest. An optical system (Differential Optical Absorption Spectroscopy - DOAS) enables the concentration of various pollutants at runway level to be recorded continuously. Since 2004, a microbalance device (Tapered Element Oscillating Microbalance – TEOM) has been measuring concentrations of fine particles with an aerodynamic diameter of 10 micrometers or less (PM10).

A network of 16 diffusive samplers was installed in 2003 along the flight-path within the airport enclosure and beyond to obtain a better assessment of the nitrogen dioxide (NO2) concentrations.

Gaseous immissions measured by the EOLE station are incorporated in the atmospheric pollution observation network of Geneva canton (ROPAG), which includes eight fixed stations at different sites in Geneva canton. Measurements of EOLE and the diffusive samplers are validated and processed by the Air Protection Service of Geneva canton (SPAir).

Measures to limit or reduce gaseous emissions are taken at source. They have a long term effect when they involve changes in the way air transport operators work or a change in the behaviour of airport users and personnel. Genève Aéroport is implementing actions appropriate to the sources of pollution in question in the following fields:

• Financial incentive for airlines
• Limitation of emissions at the airport
• Surface access: promoting sustainable modes of transport.

Since 1998, a surcharge on gaseous emissions has been levied on airlines to encourage them to fly to and from Geneva with their least polluting aircraft. Aircraft are divided into classes (five for jets, five for turboshaft and piston engines) according to their charging emission factor. Swiss and Swedish airports were among the first to introduce a surcharge of this kind, adding to other charges (calculation sheet).

Revenue from the surcharge on gaseous emissions and the noise surcharge are paid into the "Environment Fund" of Genève Aéroport and assigned to the financing of measures implemented in the environmental management.

Fixed systems for the supply of electricity and preconditioned air (GPSS) to aircraft are available at all 21 main aircraft stands. The use of Auxiliary Power Units (APU) is thus strictly limited, thereby considerably reducing pollution and noise from aircraft on the ground.

Priority is given to less polluting vehicles when renewing the airport vehicle fleet. A "green" vehicle purchasing policy has been clearly defined for Genève Aéroport. Each year Genève Aéroport buys on average 2 to 4 electric cars or vehicles with hybrid engines (electric-petrol).

A range of measures intended to encourage third parties operating at the airport to modernise their vehicle fleet is planned over the coming years.

Since 2008, diesel distributed at the airport has included 5% of biodiesel produced in Switzerland.

The optimisation and renewal of heating and air conditioning systems make it possible to limit energy consumption and gaseous emissions.

On the occasion of the renewal of its Swiss federal operating concession, Genève Aéroport committed itself to actively promoting public transport and non-motorised transport (bike, walk) aiming at the airport personnel, passengers and visitors. This strategy implies a substantial improvement of public transport services to the airport and efficient encouraging measures.

Since 2002, Genève Aéroport acts in favour of modes of sustainable transport (public transport and non-motorised transport) within its mobility plan of airport personnel in conjunction with Unireso and the Federal Railways (CFF). As a result, the employees of airport authorities and companies are able to benefit from reduced-price tickets on public transport and the use of a free shuttle service which operates early in the morning and late at night. Non-motorised transport is encouraged by appropriate infrastructures and promotional campaigns. Car park passes are allocated to airport employees according to strict criteria and prices are gradually being increased. The result of these measures is encouraging and points to an increase in the usage rate of sustainable modes of transport.

Genève Aéroport has also encouraged the use of public transport by airline passengers by proposing a range of offers. In particular, passengers arriving at the airport can use buses, trams, trains and boats in Geneva free of charge for 80 minutes.

Measures and incentives aimed at airport personnel and airline passengers will be reinforced and extended over the coming years.

In 2009, the airport's mobility plan won two prizes: The European mobility plan prize awarded by EPOMM (European Platform On Mobility Management), and the swiss cyclophile company award which recognises swiss companies for their efforts to promote cycling.