Stansted Airport has been awarded the Carbon Trust Standard after introducing a range of energy-saving programmes.
The Essex airport gained the certification after achieving a two percent emissions reduction from its buildings and vehicles between January 2007 and December 2009.
Stansted has implemented a number of initiatives in recent years, including the installation of biomass technology as part of its £50 million terminal extension.
Meanwhile, its staff have been encouraged to turn off electrical items overnight, while low-energy lighting has been installed on the airfield.
Andy Jefferson, Stansted’s head of health, safety and environment, said he is "extremely proud" that the Carbon Trust Standard can be added to the airport’s "portfolio of environmental credentials".
"While celebrating this success, we also know there is more we can and must do," he explained.
"Around 92 percent of emissions from our buildings are generated by electricity use, so we’ve set a challenging target to reduce 2010 levels by five percent compared to 2009."
In July, the Civil Aviation Authority granted Stansted Code F status, which gives the go ahead for Boeing 747-8 and Airbus A380 aircraft to land at the airport.