Flights that originate and terminate in Pacific airspace result in the creation of far higher levels of ozone pollution than those that originate and terminate in other parts of the world, new research from the Massachusetts Institute of Technology has found. Specifically — the region of Pacific airspace that encompasses Australia and New Zealand is some of the most sensitive to the creation of ozone as a result of aircraft pollution, and as a result, individual flights in this area create larger amounts of ozone than flights anywhere else in the world.
Ozone is a powerful greenhouse gas with short-term effects that are comparable to those of CO2. Aircraft pollution is a strong driver of ozone production.
The new work was done by utilizing a “global chemistry-transport model to investigate which parts of the world are specifically sensitive to the creation of ozone”. What the work found, was that an area over the Pacific — about 1000 km to the east of the Solomon Islands — was a good deal more sensitive to aircraft emissions than anywhere else.
According to the researchers, one kg of aircraft emissions in this region — specifically oxides of nitrogen (NOx) such as nitric oxide and nitrogen dioxide — results in roughly fifteen kg of extra ozone being produced in a one-year time-span. What that means is that the sensitivity in this region is about “five times higher than the sensitivity in Europe and 3.7 times higher than the sensitivity in North America.”
Steven Barrett, lead author of the new research paper, stated: “Our findings show that the cleanest parts of the atmosphere exhibit the most dramatic response to new emissions. New emissions in this part of the Pacific will result in a relatively larger response from the atmosphere.”
The press release provides more:
In an analysis of around 83,000 individual flights, the researchers found that the 10 highest ozone-producing flights either originated, or were destined for, either New Zealand or Australia. A flight from Sydney to Bombay was shown to produce the highest amount of ozone — 25,300 kg — as the majority of the flight passed through the area in the Pacific where the sensitivity was the highest.
Furthermore, the aircraft leaving and entering Australia and New Zealand are usually very large and the flight times are often very long, meaning more fuel would be burnt and more NOx emitted.
Ozone is a relatively short-lived greenhouse gas, and its production and destruction relies heavily on the local chemical state of the atmosphere, so its effects are felt in specific regions at specific times rather than on a global scale. The researchers found that flights in October cause 40 percent more NOx emissions than flights in April.
“There have been many studies of the total impact of civil aviation emissions on the atmosphere, but there is very little knowledge of how individual flights change the environment,” Barret said. “The places that the sensitivities are highest now are the fastest growing regions in terms of civil aviation growth, so there could potentially be ways to achieve significant reductions in the climate impact of aviation by focusing on re-routing aircraft around the particular regions of the world where ozone formation is highly sensitive to NOx emissions..”
“Of course, longer flights are going to burn more fuel and emit more CO2, so there will be a trade-off between increasing flight distance and other climate impacts, such as the effect of ozone. The scientific underpinning of this trade-off needs further investigation so that we have a better understanding and can see whether such a trade-off can be justified,” Barrett explained.
The new findings were just published in IOP Publishing’s journal Environmental Research Letters.
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