According to Transport & Environment non-CO2 effects account for approximately two-thirds of aviation’s total climate impact, but no mitigation measures have so far made it into the EU’s aviation climate package, with some airlines even opposing the monitoring of contrails altogether.
When we think about the environmental impact of aviation, carbon dioxide (CO2) emissions often take centre stage. And rightly so, as CO2 is a major contributor to climate change. However, there’s another side to the story that often goes unnoticed: non-CO2 emissions.
Non-CO2 emissions from aviation include a variety of pollutants such as nitrogen oxides (NOx), sulphur oxides (SOx), particulate matter (PM), and water vapor. While these emissions may not stay in the atmosphere as long as CO2, they can have significant short-term effects on the environment and human health.
Contrails
Contrails are the thin clouds formed by water vapour in aircraft exhaust. In certain conditions, specifically where aeroplanes fly through areas that are both very cold and very humid, contrails are generated that can trap heat, contributing to global warming. The overall impact of contrails on climate change is still being studied, but it’s clear that they play a role in atmospheric dynamics.
NOx
One of the primary non-CO2 emissions from aircraft is NOx. These pollutants are formed when nitrogen in the air reacts with oxygen during the combustion process in engines. NOx emissions contribute to the formation of ground-level ozone and particulate matter, which can lead to respiratory problems and other health issues for nearby communities.
SOx
Although modern aircraft use low-sulphur fuels to reduce SOx emissions, they can still have an impact, especially near airports and heavily trafficked flight paths. Sox can contribute to acid rain and have negative effects on ecosystems and human health.
Particulate matter
These tiny particles can penetrate deep into the lungs when inhaled, leading to respiratory and cardiovascular problems. While aircraft engines have become more efficient over the years, they still produce PM emissions, particularly during take off and landing.
Addressing non-CO2 emissions in aviation requires a multi-faceted approach. From technological advancements to operational changes, there are several strategies that can help mitigate the environmental impact of air travel.
Unlike conventional aircraft, Airlander is an innovative hybrid aircraft that operates at much lower altitudes, offering a unique solution to the problem of non-CO2 emissions in aviation.
Even in an all-kerosene engine configuration Airlander takes less than half the energy of a conventional aeroplane to carry the same number of passengers the same distance, due to its inherently efficient design. This means Airlander also generates more than a 50% reduction in NOx, SOx, and particulates. This will be reduced to zero when the all-electric configuration of Airlander is introduced by 2030.
Traditional jets typically cruise at high altitudes to maximise fuel efficiency, but this comes with a trade-off in terms of non-CO2 emissions. At higher altitudes, jet engines produce more nitrogen oxides (NOx) and contrails, contributing to air pollution and climate change.
In contrast, Airlander operates at altitudes of around 10,000 feet. By flying closer to the ground, Airlander avoids the atmospheric conditions that lead to the formation of contrails and reduces its NOx emissions. This makes Airlander a promising alternative for industries and applications where flying at a high altitude is not required.
As technology continues to evolve and demand for eco-friendly transportation grows, Airlander will play an important role in shaping the aviation industry's environmental impact.