A strategy to reduce emissions from aircraft at Heathrow is reaching its limits, meaning that further emissions reductions need to happen from road traffic cuts.
Researchers at Imperial College London’s civil engineering department have been studying how emissions from aircraft during take off have been reduced at Heathrow Airport.
Pilots can choose the “thrust” setting during take off, which is the force required to propel the aircraft forwards. By using “reduced thrust”, pilots can lower the force generated by the engines during take off, if the aircraft is not full.
Using “reduced thrust” settings reduces nitrogen oxide (NOx) and black carbon (BC) emissions, and increases fuel efficiency, according to a report by researchers at Imperial College London.
But researchers also suggested that reduced thrust is deployed well at Heathrow and so is reaching its limits in terms of effectiveness. It means that reducing traffic around the airport will be a quicker way to achieve emissions reductions while advances in engine technology catch up.
“Now that the Government has backed the expansion of Heathrow there is a need for a close examination of how we can tackle the projected overall increase in emissions around the airport in the future,” said the report’s co-author Marc Stettler, a lecturer in transprt and the environment at Imperial’s department of civil and environmental engineering.
“Our study indicates that significant improvements in air quality, specifically NOx, can only be achieved with a strategy that fully addresses road traffic emissions around the airport, which is the major emissions source.”
The draft Airports National Policy Statement (NPS), which is currently out for public consultation, sets out requirements for landside traffic around Heathrow to be kept at today’s levels, ensuring that 50% of journeys are made using public transport by 2030.
“Heathrow takes air quality issues seriously and as part of our plans for expansion will transform public transport to the airport to fight the real source of emissions – road vehicles,” said a spokesperson for Heathrow Airport Ltd.
“We are so confident in our mitigation plans that we are calling on the Government to set up independent regulation to further scrutinise our plans and hold us to our promises.”
Researchers analysed 3,336 reduced thrust take offs at Heathrow Airport for the report, published in the journal Transportation Research. It found that reduced thrust decreased fuel consumption by around 23%, NOx by up to almost 48% and BC emissions by up to 71%.