Annual nitrogen dioxide levels at Gatwick fell from 32 to 31 micrograms per cubic metre in 2014 – well below the legal limit of 40, according to a new report.
The study tracks Gatwick’s progress on a series of environmental targets as the airport pushes its green credentials against rival Heathrow in the battle to win government approval for expansion.
Heathrow is being backed by the Airports Commission to build a third runway over expanding Gatwick with a decision due by the government before the end of the year.
Gatwick has guaranteed not to breach legal air quality measures if allowed to build a second runway.
The West Sussex airport claims it can do this as it is located in a more sparsely populated area and also attracts airlines operating one of the cleanest aircraft fleets in Europe.
Chief executive, Stuart Wingate, said: “Air quality is more relevant to the expansion debate than it has ever been.”
He claimed that “illegal air quality” has stopped expansion at Heathrow in the past.
“Given it is even worse today than ever it is hard to see how expansion could legally go ahead there with millions more car journeys – yet alone all the construction traffic,” Wingate added.
Gatwick’s ‘Decade of Change’ report also shows that it is using less water, electricity and gas, and that more passengers are using public transport to get to the airport.
Gatwick’s directly controlled carbon emissions also remained steady last year despite an 8% increase in passenger numbers – keeping the airport on track to achieve its goal of reducing these carbon emissions by 50% by 2020.
Wingate, said: “Today’s positive figures are further proof that Gatwick expansion can be delivered lawfully.
“Gatwick has operated within legal air quality limits for more than a decade and can guarantee that it will continue to meet these legal limits even with a second runway.”